Final Professional MBBS — Ophthalmology (complete, 12 chapters). Explanation-first answers with anatomical, optics, neuro & public-health diagrams, classifications, comparison tables, drug doses, clinical pearls and key-point recaps from Khurana's Comprehensive Ophthalmology, Parsons' Diseases of the Eye and Park's PSM.
12chapters144questions39High-Yield
THE CONCEPT
Uveitis is inflammation of the uveal tract (iris, ciliary body and choroid). Anterior uveitis — inflammation of the iris (iritis) and ciliary body (cyclitis), together called iridocyclitis — is the commonest form. It may be acute or chronic, and granulomatous or non-granulomatous, and it presents as a painful red eye that must be distinguished from other causes of red eye.
CAUSES
Many cases are idiopathic, but important associations are HLA-B27 spondyloarthropathies (ankylosing spondylitis, reactive arthritis, psoriatic arthritis, inflammatory bowel disease), juvenile idiopathic arthritis (a chronic, painless uveitis in children), sarcoidosis, tuberculosis, herpes, Behçet's disease, syphilis and trauma.
SYMPTOMS & SIGNS
The patient has a painful red eye with photophobia, watering and blurred vision (chronic forms, such as JIA, may be almost symptomless). The signs are characteristic:
Ciliary (circumcorneal)
congestion
Keratic precipitates
(on endothelium, inferior)
Small, irregular
pupil (miosis +
synechiae)
Signs of acute anterior uveitis (iridocyclitis): deep ciliary (circumcorneal) congestion, keratic precipitates deposited on the lower corneal endothelium, and a small, irregular pupil from miosis and posterior synechiae. The aqueous also shows cells and 'flare'.
Ciliary (circumcorneal) congestion — a deep, violaceous redness around the limbus.
Keratic precipitates (KPs) — inflammatory cells on the corneal endothelium (mutton-fat in granulomatous, fine in non-granulomatous disease).
Aqueous cells and flare — the hallmark of active anterior-chamber inflammation.
Miosis and posterior synechiae — a small, irregular pupil that dilates poorly (a 'festooned' pupil).
Iris nodules (Koeppe, Busacca) in granulomatous disease, and a hypopyon in severe cases (e.g. Behçet's, HLA-B27).
MANAGEMENT
The two pillars of treatment are:
Topical corticosteroids (prednisolone acetate) — the mainstay to suppress inflammation, tapered slowly.
Cycloplegic/mydriatic drops (atropine, homatropine, cyclopentolate) — to relieve painful ciliary spasm and to prevent and break posterior synechiae.
Plus treating any underlying cause, controlling raised IOP, and periocular/systemic steroids or immunosuppression for severe or posterior involvement.
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CLINICAL PEARL: Acute anterior uveitis is a painful, photophobic red eye with ciliary congestion, keratic precipitates, aqueous cells and flare, miosis and posterior synechiae. Think HLA-B27 (ankylosing spondylitis and related), sarcoidosis, TB, herpes and Behçet's — and JIA (chronic, painless) in children. Treat with topical steroids plus a cycloplegic, treat the cause, and watch for synechiae → glaucoma, cataract and cystoid macular oedema.
UNDERSTANDING 'CELLS AND FLARE'
The single most important sign of active anterior uveitis is cells and flare in the anterior chamber, and it is worth understanding what these are. Normally the aqueous is optically empty. When the inflamed iris and ciliary vessels become leaky (a breakdown of the blood–aqueous barrier), inflammatory cells spill into the aqueous (seen as tiny motes drifting in the slit-lamp beam) and leaked protein makes the beam itself look hazy or smoky ('flare'). The number of cells grades the activity of the inflammation and is used to monitor the response to treatment, while flare reflects the protein leak. Recognising and grading cells and flare is therefore central to diagnosing and following anterior uveitis.
DISTINGUISHING IT FROM OTHER RED EYES
A crucial clinical skill is separating anterior uveitis from the other causes of an acute red eye — conjunctivitis and acute angle-closure glaucoma — because their treatments differ completely and getting it wrong is dangerous. Uveitis has ciliary (circumcorneal) congestion, a small pupil, normal or slightly reduced vision, cells and flare, and a normal or soft eye; conjunctivitis has superficial peripheral redness, discharge, a normal pupil and normal vision; while acute angle-closure has a hazy cornea, a fixed mid-dilated pupil, a stony-hard eye and severe pain with haloes. Sorting the red eye by the pattern of congestion, the pupil, the cornea and the pressure is a core examination competency.
A NOTE ON THE HLA-B27 CONNECTION
The strongest and most examinable association of acute anterior uveitis is with HLA-B27. A large proportion of patients with a recurrent, acute, unilateral (alternating), non-granulomatous anterior uveitis are HLA-B27 positive, and this links the eye to the seronegative spondyloarthropathies — ankylosing spondylitis, reactive arthritis, psoriatic arthritis and inflammatory bowel disease. Such attacks can be severe, sometimes with a hypopyon and fibrin, but typically respond well to treatment and recur in either eye over the years. Recognising this pattern prompts appropriate questions about back pain and stiffness, joints, skin and bowel symptoms, and appropriate referral, so that the systemic disease is not missed behind the recurrent red eye.
Treat with topical steroids + cycloplegic + the underlying cause; watch for synechiae→glaucoma, cataract, cystoid macular oedema.
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SOURCES: Khurana's Comprehensive Ophthalmology; Parsons' Diseases of the Eye.
THE CONCEPT
Uveitis is inflammation of the uveal tract, but because the uvea is intimately related to the retina, cornea and sclera, uveitis is really inflammation of the whole inner eye. A systematic classification — by anatomy, clinical type, course and cause — is essential because it guides the investigation and treatment of what is otherwise a bewilderingly varied group of diseases.
The uveal tract (uvea)
Iris
Ciliary body
Choroid
Uvea = iris + ciliary body + choroid — the pigmented, highly vascular middle coat
The uveal tract (uvea) is the pigmented, highly vascular middle coat of the eye, formed by the iris and ciliary body in front (the anterior uvea) and the choroid behind (the posterior uvea). Uveitis is inflammation of any part of this tract.
ANATOMICAL CLASSIFICATION (the SUN system)
Anterior uveitis — iritis/iridocyclitis (the commonest).
Intermediate uveitis — inflammation of the vitreous and pars plana (pars planitis).
Posterior uveitis — choroiditis, retinitis or chorioretinitis.
Panuveitis — inflammation involving all parts.
CLINICAL CLASSIFICATION
Uveitis is also divided into granulomatous (insidious, with mutton-fat KPs and iris nodules — e.g. TB, sarcoidosis, sympathetic ophthalmia, VKH, syphilis) and non-granulomatous (acute, with fine KPs and no nodules — e.g. HLA-B27, idiopathic, trauma), and by course (acute, recurrent or chronic).
CAUSES
Infective — TB, syphilis, herpes (HSV/VZV), toxoplasmosis (the commonest posterior uveitis), CMV (in the immunocompromised), toxocara.
Masquerade syndromes — intraocular lymphoma, leukaemia and (in children) retinoblastoma, which can mimic uveitis.
Traumatic, lens-induced and sympathetic uveitis.
PRACTICAL APPROACH
A careful history and examination localise the uveitis and suggest a cause. A single, mild, unilateral, non-granulomatous anterior attack often needs no investigation, whereas recurrent, bilateral, granulomatous or posterior uveitis warrants a tailored work-up (HLA-B27, chest imaging and ACE for sarcoid, TB testing, syphilis serology, and specific serology as indicated).
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CLINICAL PEARL: Classify every uveitis three ways: anatomically (anterior/intermediate/posterior/pan — the SUN system), clinically (granulomatous vs non-granulomatous), and by cause. Remember anterior is commonest and toxoplasmosis is the commonest posterior uveitis; think infective (TB, syphilis, herpes, toxoplasma), autoimmune (HLA-B27, sarcoid, Behçet, VKH, JIA) and masquerade (lymphoma, retinoblastoma). Investigate the recurrent, bilateral, granulomatous or posterior cases.
WHY CLASSIFICATION MATTERS FOR INVESTIGATION
The value of classifying uveitis is that it prevents both over- and under-investigation. A young adult with a first, mild, unilateral, acute non-granulomatous anterior uveitis that settles quickly needs no laboratory tests at all — investigating them is wasteful and often misleading. By contrast, a recurrent, bilateral, granulomatous or posterior uveitis, or one with systemic symptoms, must be worked up because it is far more likely to reflect a treatable systemic disease. The anatomical and clinical classification therefore acts as a filter that targets investigation at the patients most likely to benefit, which is why establishing the type precedes ordering any tests.
A NOTE ON MASQUERADE SYNDROMES
An important safety point built into the classification is the group of masquerade syndromes — non-inflammatory conditions that imitate uveitis. In an older patient with an atypical, steroid-resistant 'uveitis', intraocular lymphoma must be considered; in a child, retinoblastoma or leukaemia can present with pseudo-inflammation. Missing these is dangerous because they are malignant and life-threatening. This is why a uveitis that behaves atypically — the wrong age, unusually resistant to treatment, or with atypical features — prompts a search for a masquerade, rather than simply escalating anti-inflammatory therapy. Building this caution into the diagnostic approach can be life-saving.
A NOTE ON THE ROLE OF INVESTIGATIONS
When investigation is warranted, it should be directed by the clinical picture, not a blanket screen. Useful, targeted tests include HLA-B27 (recurrent acute anterior uveitis), a chest X-ray/CT and serum ACE or calcium (sarcoidosis), tuberculin/interferon-gamma release assay (TB), syphilis serology (VDRL/TPHA), and specific serology or imaging for suspected toxoplasmosis, herpes or other causes. The principle is that the history and examination generate a short differential, and only the relevant tests are ordered to confirm or exclude it. This targeted strategy avoids the low yield and false positives of indiscriminate testing, and it is why establishing the anatomical and clinical class of the uveitis comes first.
Investigate recurrent, bilateral, granulomatous or posterior uveitis; a single mild anterior attack often needs none.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Sympathetic ophthalmia is a rare but devastating bilateral, granulomatous panuveitis that follows a penetrating injury (or intraocular surgery) to one eye. The injured eye is called the 'exciting eye' and the fellow eye, which becomes inflamed, the 'sympathising eye'. The tragedy is that a hopelessly injured eye can, through this reaction, cost the patient the sight of their good eye.
MECHANISM
It is an autoimmune (T-cell-mediated) reaction against uveal/retinal antigens that are normally hidden from the immune system but become exposed by the penetrating injury. The sensitised immune system then attacks the same antigens in the healthy fellow eye. It typically develops 2 weeks to 3 months after the injury (with a range from days to decades).
CLINICAL FEATURES
The sympathising eye develops an insidious anterior uveitis (photophobia, blurring, redness) that progresses to a panuveitis, with mutton-fat keratic precipitates, and characteristic yellow-white Dalen–Fuchs nodules (at the level of the retinal pigment epithelium), papillitis and exudative retinal detachment. The exciting eye remains inflamed.
PREVENTION & TREATMENT
Prevention — enucleation of a blind, badly-injured eye within about 10–14 days of injury (before sympathetic ophthalmia can develop) is the classic teaching, together with meticulous primary repair of any salvageable eye.
Treatment (once established) — high-dose systemic corticosteroids plus long-term immunosuppression, with topical steroids and cycloplegics; aggressive treatment can preserve useful vision in the sympathising eye.
Enucleation of the exciting eye after sympathetic ophthalmia has begun is controversial and reserved for an eye with no useful vision.
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CLINICAL PEARL: Sympathetic ophthalmia is a bilateral granulomatous panuveitis after a penetrating injury/surgery to one eye — an autoimmune reaction to exposed uveal antigens spreading from the exciting eye to the sympathising eye. Look for Dalen–Fuchs nodules. Prevent it by early enucleation of a blind injured eye (within ~2 weeks) or meticulous repair; treat established disease with systemic steroids and immunosuppression.
WHY THE INJURED EYE IS THE KEY TO PREVENTION
The whole importance of sympathetic ophthalmia lies in prevention, and understanding the timeline explains why. There is a latent interval (usually a fortnight to three months) between the injury and the onset of disease in the fellow eye. This creates a window in which a blind, irreparably injured eye can be removed before it sensitises the immune system and endangers the good eye. Hence the classic teaching to enucleate a hopelessly damaged eye within about 10–14 days. Once sympathetic ophthalmia has already begun, however, removing the exciting eye no longer reliably helps (the immune process is established), which is why the emphasis is on early decision-making about the injured eye and on meticulous repair of any eye that might be saved.
THE RELATIONSHIP TO VOGT–KOYANAGI–HARADA
It is worth knowing that sympathetic ophthalmia is closely related, both clinically and immunologically, to Vogt–Koyanagi–Harada (VKH) disease — the two share a bilateral granulomatous panuveitis with Dalen–Fuchs nodules and exudative retinal detachment, and both are directed against melanocyte/uveal antigens. The key difference is that sympathetic ophthalmia follows a penetrating injury or surgery, whereas VKH arises spontaneously and is accompanied by systemic features (meningism, hearing loss, vitiligo, poliosis and alopecia). Recognising this relationship helps explain the shared appearance and the shared treatment principle of prolonged systemic steroids and immunosuppression.
A NOTE ON THE HISTOPATHOLOGY
The histopathology of sympathetic ophthalmia is characteristic and helps explain the disease. There is a diffuse granulomatous inflammation of the whole uveal tract, composed of lymphocytes with epithelioid cells and multinucleate giant cells, which classically spares the choriocapillaris and the retina in the early stages. The small nodular collections of epithelioid cells and pigment-laden macrophages beneath the retinal pigment epithelium are the Dalen–Fuchs nodules seen clinically as yellow-white dots. This granulomatous, antigen-driven pattern — targeting melanocyte-associated antigens throughout the uvea of both eyes — accounts for the bilateral, chronic, relapsing nature of the disease and for its overlap with VKH.
A NOTE ON THE MODERN OUTLOOK
The outlook for sympathetic ophthalmia has improved dramatically with modern treatment. Before effective immunosuppression it was a common cause of bilateral blindness, but with prompt, aggressive and prolonged systemic corticosteroids and steroid-sparing immunosuppressants (such as ciclosporin, azathioprine, mycophenolate or biologic agents), many sympathising eyes now retain useful vision. The disease nonetheless tends to be chronic and relapsing, requiring long-term specialist follow-up and careful monitoring for both recurrences and drug side-effects. This transformation — from a feared cause of blindness to a treatable condition — underlines why the emphasis remains on prevention through early management of the injured eye and on early, adequate immunosuppression once the disease appears.
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KEY POINTS / NUMBERS (viva)
Sympathetic ophthalmia = bilateral granulomatous panuveitis after penetrating injury/surgery to one eye (exciting → sympathising eye).
Autoimmune (T-cell) reaction to exposed uveal/retinal antigens; onset usually 2 weeks–3 months (range days–decades); Dalen–Fuchs nodules.
Prevent: enucleate a blind badly-injured eye within ~10–14 days, or meticulous repair; treat: high-dose systemic steroids + long-term immunosuppression.
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KEY POINTS TO REMEMBER
Sympathetic ophthalmia = rare bilateral granulomatous panuveitis after a penetrating injury/surgery to one eye.
SOURCES: Khurana's Comprehensive Ophthalmology; Parsons' Diseases of the Eye.
THE CONCEPT
Endophthalmitis is a severe infection/inflammation of the inner cavities of the eye (the aqueous and, especially, the vitreous). Panophthalmitis is more extensive still — inflammation of all the coats of the eye including the sclera, and spread into the orbit (Tenon's space). Both are ophthalmic emergencies that can rapidly destroy the eye.
ENDOPHTHALMITIS — TYPES & ORGANISMS
Exogenous — organisms enter from outside: post-operative (after cataract surgery — the commonest cause), post-traumatic (penetrating injury/intraocular foreign body), post-intravitreal injection, or from a perforated corneal ulcer.
Endogenous — blood-borne spread in the immunocompromised, intravenous drug users or those with systemic sepsis (including Candida).
Common organisms are coagulase-negative staphylococci (acute post-cataract), streptococci, Gram-negatives, fungi, and Bacillus (aggressive, post-trauma).
CLINICAL FEATURES & MANAGEMENT
Endophthalmitis presents with rapidly worsening pain, marked visual loss, redness, lid swelling, a hypopyon, and vitritis (loss of the red reflex). It is diagnosed by an aqueous/vitreous tap for Gram stain and culture (with ultrasound to assess vitritis). Treatment is an emergency: immediate intravitreal antibiotics (vancomycin + ceftazidime), with vitrectomy in severe cases (or when vision is reduced to light perception), and intravitreal antifungals for fungal disease.
PANOPHTHALMITIS
Panophthalmitis adds signs of spread beyond the globe — severe pain, proptosis, restricted and painful eye movements, chemosis and systemic upset (fever). The eye is usually beyond saving and ends in phthisis; treatment is systemic antibiotics and evisceration (removing the contents but leaving the scleral shell) to relieve pain — enucleation is avoided because of the risk of spreading infection intracranially.
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CLINICAL PEARL: Endophthalmitis is infection of the inner eye, most often after cataract surgery: pain, hypopyon, vitritis and sudden visual loss — an emergency needing intravitreal antibiotics (vancomycin + ceftazidime) ± vitrectomy. Panophthalmitis is inflammation of all coats plus the orbit (proptosis, restricted movements, systemic signs), managed with systemic antibiotics and evisceration (not enucleation).
A NOTE ON ACUTE VS CHRONIC POST-OPERATIVE ENDOPHTHALMITIS
A useful distinction is between acute and chronic (delayed) post-operative endophthalmitis. The acute form appears within days to a couple of weeks of surgery, is usually caused by virulent organisms (staphylococci, streptococci, Gram-negatives), and is fulminant — the picture of pain, hypopyon and rapid visual loss that constitutes the classic emergency. The chronic form appears weeks to months later, is caused by low-virulence organisms (notably Propionibacterium acnes or fungi) sequestered in the capsular bag, and presents as a smouldering, granulomatous, partially steroid-responsive inflammation that is easily mistaken for ordinary post-operative uveitis. Recognising the chronic form prevents prolonged mistreatment with steroids alone.
THE IMPORTANCE OF PROMPT ACTION & PROGNOSIS
The prognosis in endophthalmitis is dictated by how quickly treatment is started, because the infection destroys retinal tissue rapidly. This is why any increasing pain and falling vision after intraocular surgery or injury is treated as endophthalmitis until proven otherwise, with an immediate tap and intravitreal antibiotics rather than waiting for culture results. The landmark evidence also showed that early vitrectomy benefits eyes presenting with vision as poor as light perception. The take-home message — mirrored in the way patients are warned at discharge — is that speed, not perfection of diagnosis, saves the eye, since even a few hours' delay can be the difference between useful vision and loss of the eye.
A NOTE ON PREVENTION IN SURGERY & TRAUMA
Because endophthalmitis is so destructive, prevention is central. In elective intraocular surgery this means preoperative povidone-iodine antisepsis, sterile technique, secure wound construction, and intracameral antibiotics (e.g. cefuroxime), together with treating any lid or lacrimal-sac infection beforehand. In penetrating trauma, prevention rests on prompt wound closure, removal of any intraocular foreign body, and prophylactic (often systemic and intravitreal) antibiotics, with a especially high index of suspicion for aggressive organisms such as Bacillus in soil-contaminated injuries. This preventive emphasis reflects the reality that, once established, endophthalmitis often damages vision despite optimal treatment — so avoiding it is far better than treating it.
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KEY POINTS / NUMBERS (viva)
Endophthalmitis = infection of inner eye (aqueous+vitreous); exogenous (post-cataract commonest, trauma, injection) or endogenous (blood-borne, Candida).
Pain, visual loss, hypopyon, vitritis (loss of red reflex); tap for Gram/culture; EMERGENCY intravitreal antibiotics (vancomycin + ceftazidime) ± vitrectomy.
Choroidal (uveal) melanoma is a malignant tumour arising from the melanocytes of the uveal tract. It is the commonest primary intraocular malignancy in adults, and although it can arise in the iris or ciliary body, the choroid is by far the commonest site. It is important because it is both sight- and life-threatening (it can metastasise).
Choroidal melanoma
'collar-stud' / mushroom shape
(breaks through Bruch's membrane)
Detached retina
(subretinal fluid)
Sclera
Choroid
Choroidal melanoma classically forms a pigmented, dome-shaped mass that, on breaking through Bruch's membrane, assumes a 'collar-stud' (mushroom) shape and lifts the overlying retina with subretinal fluid (a secondary retinal detachment).
CLINICAL FEATURES
Many are asymptomatic and found on routine examination. Symptomatic tumours cause blurred vision, a field defect, floaters or flashes (especially if the macula or a secondary retinal detachment is involved); an iris melanoma appears as a visible pigmented iris nodule. Larger tumours may cause secondary retinal detachment or glaucoma.
SIGNS & INVESTIGATION
The classic sign is a pigmented (occasionally amelanotic), elevated, dome-shaped choroidal mass; when it breaks through Bruch's membrane it forms a characteristic 'collar-stud' (mushroom) shape, often with an overlying serous retinal detachment and orange lipofuscin pigment. Investigation is largely non-invasive:
B-scan ultrasonography — shows the dome/collar-stud shape, low internal reflectivity and choroidal excavation (a key diagnostic test).
Fundus photography, fluorescein angiography and OCT for characterisation.
Systemic staging — the tumour spreads haematogenously (the eye has no lymphatics) to the LIVER (commonest) and lung, so liver imaging is done. Biopsy is generally avoided.
MANAGEMENT & PROGNOSIS
Treatment depends on size and location: small tumours may be observed or treated with laser; medium tumours with plaque brachytherapy or proton-beam radiotherapy; and large tumours by enucleation. Prognosis worsens with large size, epithelioid cell type, extraocular extension and monosomy 3 (a strong genetic predictor of metastasis).
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CLINICAL PEARL: Choroidal melanoma is the commonest primary intraocular malignancy in adults — a pigmented, dome-shaped or 'collar-stud' (mushroom) choroidal mass that breaks through Bruch's membrane, with low internal reflectivity on B-scan and an overlying serous detachment. It spreads haematogenously to the LIVER. Treat by size (observation/brachytherapy/enucleation); remember monosomy 3 predicts metastasis.
THE DIFFERENTIAL OF A PIGMENTED FUNDUS LESION
A practical clinical problem is distinguishing a small choroidal melanoma from a benign choroidal naevus, which is extremely common. Features that suggest malignancy (and warrant referral/monitoring) are summarised in the mnemonic 'To Find Small Ocular Melanoma': Thickness >2 mm, Fluid (subretinal), Symptoms, Orange pigment (lipofuscin), and Margin touching the disc. A flat, uniformly pigmented lesion with drusen and no fluid or symptoms is more likely a benign naevus. Because early, small melanomas are the most treatable, recognising these risk factors for growth — rather than dismissing every pigmented spot — is an important skill, and suspicious lesions are referred for ultrasound and serial observation.
A NOTE ON METASTASIS & LIFELONG SURVEILLANCE
A sobering feature of uveal melanoma is its tendency to metastasise late and almost exclusively to the liver, sometimes many years after apparently successful treatment of the eye. Because the eye has no lymphatic drainage, spread is haematogenous, and micrometastases may already be present at diagnosis even when the eye is cured. This is why genetic/cytogenetic profiling of the tumour (especially monosomy 3 and gene-expression class) is used to stratify metastatic risk, and why patients undergo long-term systemic surveillance with liver imaging. It also explains why local control of the eye tumour, though important for the eye, does not by itself guarantee cure — a crucial point when counselling patients about prognosis.
A NOTE ON THE OTHER INTRAOCULAR TUMOURS
It helps to place choroidal melanoma among the other intraocular tumours. In children, the important primary intraocular malignancy is retinoblastoma (presenting with leukocoria and strabismus), not melanoma. In adults, aside from primary uveal melanoma, the eye is a site for metastatic tumours (which are actually the commonest intraocular malignancy overall — typically from breast in women and lung in men, often multiple and bilateral), and for choroidal haemangioma and metastatic deposits. Distinguishing a solitary pigmented melanoma from an amelanotic metastasis or a benign naevus/haemangioma relies on the history, the appearance, and ultrasound characteristics — which is why a careful systemic history and examination accompany the ocular assessment of any choroidal mass.
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KEY POINTS / NUMBERS (viva)
Choroidal melanoma = commonest primary intraocular malignancy in adults; choroid > ciliary body > iris.
Posterior synechiae are inflammatory adhesions between the posterior surface of the iris and the anterior capsule of the lens. They form when the fibrinous exudate of anterior uveitis (iritis) glues the iris to the lens, and are a common and important complication of iridocyclitis.
Pupil dilates but stays tethered at points (red) → irregular 'festooned' shape
Posterior synechiae: inflammatory adhesions bind the iris to the front of the lens at several points (red), so on dilation the pupil is pulled into an irregular, scalloped ('festooned') shape instead of a smooth circle.
CONSEQUENCES
They make the pupil irregular and slow to dilate ('festooned'). If adhesions form all the way around the pupil margin (360°) — seclusio pupillae — aqueous can no longer pass from the posterior to the anterior chamber; pressure then bows the iris forward ('iris bombé') and closes the angle, causing secondary angle-closure glaucoma. If exudate covers the whole pupil, it is called occlusio pupillae.
PREVENTION & TREATMENT
The key is prevention with cycloplegic/mydriatic drops (atropine) during active uveitis — keeping the pupil dilated and mobile stops synechiae forming and can break fresh ones — together with steroids to control the inflammation.
A NOTE ON PERIPHERAL ANTERIOR SYNECHIAE
It is worth distinguishing posterior synechiae (iris-to-lens) from peripheral anterior synechiae (PAS), which are adhesions of the iris root to the trabecular meshwork/cornea at the angle. Whereas posterior synechiae distort the pupil and can cause pupil-block (iris bombé) glaucoma, PAS directly obstruct the drainage angle and cause a synechial (secondary angle-closure) glaucoma. Both result from inflammation and both raise the pressure, but by different mechanisms — a distinction made on gonioscopy and one that influences how the secondary glaucoma is managed.
THE BOTTOM LINE
Posterior synechiae bind the iris to the lens in anterior uveitis, distorting the pupil and, if complete, causing pupil-block (iris bombé) glaucoma — which is why cycloplegics to keep the pupil mobile are given alongside steroids.
IN PRACTICE
In practice, the presence of posterior synechiae is documented after attempting dilation, and the aim of treatment is to break fresh, filmy adhesions early with intensive mydriasis before they become fixed and organised — because established synechiae are permanent and predispose to the pupil-block glaucoma that makes uveitis sight-threatening.
Finally, the finding of any posterior synechiae signals that the inflammation is significant and warrants firm treatment, and their number and permanence help gauge the chronicity and severity of the underlying uveitis at a glance.
A further point is that synechiae can be broken pharmacologically even after they form, using intensive short-acting mydriatics (such as phenylephrine and cyclopentolate together, sometimes with subconjunctival mydricaine), provided they are recent and filmy; long-standing, organised synechiae, however, are permanent and may need surgical division at the time of cataract surgery. This is why early, vigorous dilation during an acute attack of iritis is emphasised — the chance to prevent or reverse them is greatest at the outset.
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KEY POINTS TO REMEMBER
Posterior synechiae = adhesions between the iris and the anterior lens capsule from inflammatory exudate in anterior uveitis.
Cause an irregular, poorly-dilating ('festooned') pupil.
Prevent/break with cycloplegic-mydriatic drops (atropine) + treat the uveitis with steroids.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Choroiditis is inflammation of the choroid (the posterior uvea), and because the choroid lies directly beneath the retina it almost always involves the retina too (chorioretinitis). Unlike anterior uveitis it is usually painless and without redness (no anterior-segment involvement), but it directly threatens vision.
CAUSES & FEATURES
The commonest cause is toxoplasmosis (a focal necrotising retinochoroiditis); others include tuberculosis, sarcoidosis, syphilis, CMV (in the immunocompromised), Vogt–Koyanagi–Harada and sympathetic ophthalmia. Symptoms are floaters, blurred vision and scotomata. Signs are vitritis (cells/haze), yellow-white active choroidal/retinal lesions, and pigmented scars where old lesions have healed. In toxoplasmosis an active lesion beside an old pigmented scar gives the classic 'headlight in the fog' appearance.
MANAGEMENT
Treatment is directed at the cause — for example pyrimethamine, sulfadiazine and steroid for sight-threatening toxoplasmosis, and systemic steroids/immunosuppression for the autoimmune causes.
A NOTE ON CONGENITAL VS ACQUIRED TOXOPLASMOSIS
Toxoplasma retinochoroiditis deserves a further note because it has two forms. Congenital toxoplasmosis (from transplacental infection) classically causes bilateral macular scars and may be part of a wider picture (hydrocephalus, intracranial calcification), reactivating later in life beside the old scars. Acquired toxoplasmosis produces focal lesions too. The characteristic recurrence of an active fluffy lesion at the edge of a pigmented scar is the classic sign, and treatment is reserved for sight-threatening lesions (near the macula or disc) or heavy vitritis, since many peripheral lesions heal spontaneously in the immunocompetent.
THE BOTTOM LINE
Choroiditis is a painless, sight-threatening posterior uveitis (commonest cause toxoplasmosis) recognised by vitritis and yellow-white lesions with pigmented scars, and treated according to its cause.
IN PRACTICE
When assessing posterior uveitis, the pattern and location of the lesions guides the cause — a solitary lesion beside a scar suggests toxoplasma, multifocal choroiditis with systemic features suggests sarcoid or VKH, and a necrotising retinitis in an immunocompromised patient suggests CMV — so the fundus appearance itself is a major diagnostic clue.
In immunocompromised patients a necrotising retinitis needs urgent identification because CMV and progressive outer retinal necrosis can blind rapidly, so posterior uveitis in this group is treated as an emergency until an infective cause is excluded or specifically treated.
It is also worth noting that posterior uveitis is investigated more readily than a first anterior attack, because it is more often bilateral, chronic and linked to a systemic or infective cause; targeted serology, chest imaging and, where a masquerade is suspected, vitreous sampling help establish the diagnosis so that sight-threatening lesions near the macula or disc are treated promptly and appropriately.
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KEY POINTS TO REMEMBER
Choroiditis = inflammation of the choroid (posterior uvea), usually with the retina (chorioretinitis); painless, no redness, but sight-threatening.
Commonest cause toxoplasmosis; also TB, sarcoid, syphilis, CMV (immunocompromised), VKH, sympathetic ophthalmia.
Floaters, blurred vision, scotomata; vitritis, yellow-white active lesions, pigmented healed scars; toxoplasma = 'headlight in the fog'.
Treat the cause (toxoplasma → pyrimethamine + sulfadiazine + steroid; autoimmune → systemic steroids/immunosuppression).
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Intermediate uveitis is inflammation centred on the vitreous, the peripheral retina and the pars plana (the region behind the ciliary body). When it is idiopathic it is called pars planitis. It typically affects young adults and is usually painless with a white, quiet-looking eye, so it can be overlooked.
FEATURES & CAUSES
Patients present with floaters and blurred vision. The characteristic signs are vitritis with 'snowballs' (inflammatory aggregates in the vitreous) and 'snowbanking' (a whitish exudate over the inferior pars plana). It may be idiopathic or associated with sarcoidosis, multiple sclerosis, Lyme disease or tuberculosis. The main threat to vision is cystoid macular oedema.
MANAGEMENT
Treatment follows a step-ladder: periocular or systemic corticosteroids, then immunosuppression for resistant cases, along with treating any underlying systemic cause.
A NOTE ON THE MULTIPLE SCLEROSIS LINK
A clinically important association to remember is between intermediate uveitis (pars planitis) and multiple sclerosis. A young adult presenting with intermediate uveitis has a recognised increased likelihood of harbouring, or later developing, MS, and may also have retinal periphlebitis. This makes it worth asking about neurological symptoms and, in appropriate cases, arranging further evaluation. It is a good example of how an ocular inflammation can be the presenting clue to a systemic (here neurological) disease, reinforcing why intermediate uveitis is investigated rather than simply treated locally.
THE BOTTOM LINE
Intermediate uveitis (pars planitis) is a painless vitreous inflammation of young adults with snowballs and snowbanking, threatening vision mainly through cystoid macular oedema and sometimes signalling multiple sclerosis.
IN PRACTICE
Because vision in intermediate uveitis is threatened mainly by macular oedema rather than the vitreous cells themselves, monitoring and treatment are directed at the macula (with OCT), and a stepwise escalation from periocular to systemic steroids and then immunosuppression is used to preserve central vision.
Snowbanking over the inferior pars plana is best seen with indirect ophthalmoscopy and scleral indentation, and its extent, together with the degree of macular oedema, is used to judge disease activity and the need to escalate treatment.
Finally, because intermediate uveitis runs a prolonged, relapsing course in young people, long-term follow-up and steroid-sparing immunosuppression are often needed to control it while avoiding the cataract and glaucoma that chronic steroid use itself can cause — a balance that typifies the management of all chronic uveitis.
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KEY POINTS TO REMEMBER
Intermediate uveitis = inflammation of the vitreous, peripheral retina and pars plana; idiopathic form = pars planitis.
Young adults; usually painless, white eye; floaters and blurred vision.
Signs: vitritis with 'snowballs' and inferior 'snowbanking'; main sight threat = cystoid macular oedema.
Associations: sarcoidosis, multiple sclerosis, Lyme, TB; treat with periocular/systemic steroids, then immunosuppression.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Fuchs' heterochromic iridocyclitis is a chronic, low-grade, usually unilateral anterior uveitis with a distinctive, deceptively mild picture. Its hallmark is heterochromia — the affected iris becomes lighter in colour because chronic inflammation causes iris stromal atrophy.
DISTINGUISHING FEATURES
It is characteristically a painless, white (non-congested) eye, with diffuse fine stellate keratic precipitates scattered over the whole corneal endothelium (not just the inferior triangle), and — importantly — a characteristic ABSENCE of posterior synechiae. Its main complications are cataract (very common) and secondary glaucoma. A rubella-virus association is recognised.
MANAGEMENT
The uveitis itself responds poorly to (and rarely needs) steroids; management focuses on the complications — cataract surgery (which generally has a good outcome) and control of glaucoma.
A NOTE ON WHY IT IS OFTEN MISSED
Fuchs' heterochromic iridocyclitis is frequently overlooked or misdiagnosed, and understanding why is instructive. Because the eye is white and painless, it does not present as an obvious 'red eye'; instead it often comes to attention only when the patient develops gradual visual loss from cataract, or when glaucoma is detected. The subtle heterochromia may be missed unless both irides are compared in good light (and can be hard to see in brown-eyed patients). Recognising the triad of a quiet eye, diffuse fine KPs and absent synechiae avoids the common error of treating it with escalating steroids, to which it does not respond, and directs attention instead to its treatable complications.
THE BOTTOM LINE
Fuchs' heterochromic iridocyclitis is a quiet, chronic, unilateral uveitis with iris heterochromia, diffuse fine KPs and no synechiae, whose importance lies in its cataract and glaucoma rather than the (steroid-unresponsive) inflammation.
IN PRACTICE
A helpful clinical tell is that the fine KPs of Fuchs' are distributed diffusely across the whole cornea rather than in the inferior Arlt's triangle of ordinary uveitis, and that fine iris and angle vessels may bleed slightly during cataract surgery (Amsler's sign) — features that, with the absent synechiae, confirm the diagnosis.
Because cataract surgery in Fuchs' generally gives a good visual result despite the chronic inflammation, recognising the condition reassures both patient and surgeon and shifts the focus firmly onto managing the lens and the pressure rather than chasing the low-grade uveitis with steroids.
An additional clinical clue is that, unusually for a uveitis, the intraocular pressure in Fuchs' is often raised rather than low, and the glaucoma can be difficult to control; combined with the characteristic cataract, this means these patients are followed long-term for pressure and lens changes even though the inflammation itself is mild and stable.
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KEY POINTS TO REMEMBER
Fuchs' heterochromic iridocyclitis = chronic, low-grade, usually unilateral anterior uveitis with iris heterochromia (lighter iris from stromal atrophy).
Painless white eye; diffuse fine stellate KPs over the whole cornea; characteristic ABSENCE of posterior synechiae.
Main complications: cataract (common) and secondary glaucoma; rubella association recognised.
Responds poorly to steroids (rarely needed); manage cataract (good surgical outcome) and glaucoma.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
The importance of treating uveitis promptly lies in its complications, which arise from chronic or recurrent inflammation and are a major cause of the visual loss associated with the disease. They can be grouped by the structure affected.
Secondary glaucoma (inflammatory trabecular blockage, synechial, or steroid-induced) — or, conversely, hypotony from ciliary shutdown.
Complicated cataract — a posterior subcapsular cataract from chronic inflammation and steroid use.
Cystoid macular oedema — a leading cause of reduced vision in uveitis.
Band-shaped keratopathy — especially in chronic childhood (JIA) uveitis.
Cyclitic membrane → tractional retinal detachment → phthisis bulbi (a shrunken, blind, disorganised eye) in end-stage disease.
PREVENTION
These are largely prevented by prompt, adequate treatment (steroids plus cycloplegics) and control of recurrences, which is why uveitis is treated actively rather than left to settle.
A NOTE ON CYSTOID MACULAR OEDEMA
Among the complications, cystoid macular oedema (CMO) deserves emphasis because it is the commonest cause of reduced central vision in uveitis. Persistent inflammation makes the perifoveal capillaries leaky, and fluid collects in cystic spaces at the macula, blurring central vision even when the front of the eye has settled. It is detected on OCT (and fluorescein angiography) and treated by controlling the underlying inflammation (topical/periocular/systemic steroids, sometimes with acetazolamide or anti-VEGF). Because CMO can persist and cause permanent damage, its recognition and treatment are central to preserving vision in chronic uveitis.
THE BOTTOM LINE
The complications of uveitis — synechiae/glaucoma, complicated cataract, cystoid macular oedema, band keratopathy and phthisis — are what cause its visual loss, and are largely prevented by prompt, adequate treatment.
IN PRACTICE
Anticipating these complications changes management: uveitis is treated actively and tapered slowly to prevent rebound, the intraocular pressure and macula are monitored at each visit, and recurrences are suppressed — because it is the cumulative damage of repeated or under-treated inflammation, rather than a single attack, that ultimately blinds.
Documenting the intraocular pressure, lens and macula at every visit, and treating flares promptly, is therefore the practical way these sight-threatening sequelae are kept at bay across the long course of a chronic uveitis.
It is also useful to remember that some complications are iatrogenic — prolonged topical steroids used to treat the uveitis can themselves cause cataract and steroid-induced glaucoma — so treatment is titrated to the minimum effective dose and steroid-sparing agents are introduced early in chronic disease to limit this double jeopardy.
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KEY POINTS TO REMEMBER
Uveitis complications drive its visual loss and arise from chronic/recurrent inflammation.
Secondary glaucoma (inflammatory/synechial/steroid-induced) or hypotony; complicated (posterior subcapsular) cataract.
Cystoid macular oedema (leading cause of reduced vision), band keratopathy (esp JIA), cyclitic membrane → tractional RD → phthisis bulbi.
Prevent by prompt treatment (steroids + cycloplegics) and controlling recurrences.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
An iris coloboma is a congenital gap or defect in the iris, caused by failure of closure of the embryonic (optic/choroidal) fissure during development. Because that fissure lies inferonasally, a typical coloboma is located inferonasally, giving the pupil a 'keyhole' or 'cat's-eye' shape.
ASSOCIATIONS & FEATURES
It may be isolated, or part of a larger coloboma extending to involve the ciliary body, choroid, retina and optic disc if the fissure fails to close more extensively — in which case vision is affected. It can be associated with systemic syndromes (notably CHARGE syndrome). A typical (congenital) coloboma must be distinguished from a surgical or traumatic (acquired) coloboma.
MANAGEMENT
An isolated iris coloboma is largely a cosmetic and glare problem, managed if needed with a coloured (cosmetic/painted) contact lens; associated posterior colobomas and any amblyopia or refractive error are managed on their merits.
A NOTE ON THE EMBRYOLOGY
The location of a typical coloboma is explained by embryology. During development the optic cup has a groove — the embryonic (choroidal/optic) fissure — on its inferonasal aspect, through which blood vessels enter and which normally closes around the sixth week. If closure fails, a gap persists in the structures derived from that region, which is why typical colobomas are inferonasal and why a single developmental error can produce a coloboma affecting the iris, ciliary body, choroid, retina and optic disc together. Understanding this makes sense of both the position and the frequently combined nature of colobomata, and distinguishes them from acquired defects in other locations.
THE BOTTOM LINE
An iris coloboma is a congenital inferonasal iris gap from failed fissure closure, usually cosmetic when isolated but potentially vision-limiting and syndromic when it extends to the choroid, retina and disc.
IN PRACTICE
When a coloboma is found, the whole eye is examined to determine its extent (iris alone versus a full chorioretinal coloboma reaching the disc), the fellow eye and systemic features are checked for syndromic associations, and any resulting refractive error or amblyopia in a child is treated to give the best possible vision.
Where the coloboma is purely cosmetic, patients are simply reassured and offered a coloured contact lens, but any reduced vision prompts a careful search for an associated posterior (chorioretinal or optic-disc) coloboma that explains it.
For completeness, a coloboma of the lens (a notch in its edge from a local zonular defect) or of the eyelid may coexist, and the term 'coloboma' simply denotes any such developmental gap; recognising the typical inferonasal position and checking for these associated defects distinguishes a true congenital coloboma from acquired iris defects due to surgery or trauma.
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KEY POINTS TO REMEMBER
Iris coloboma = congenital iris gap from failure of closure of the embryonic (optic) fissure; typically inferonasal ('keyhole'/'cat's-eye' pupil).
May be isolated or extend to ciliary body, choroid, retina and optic disc (then vision is affected).
Can be part of systemic syndromes (e.g. CHARGE); distinguish from surgical/traumatic (acquired) colobomas.
Isolated form is mainly cosmetic/glare (coloured contact lens); manage posterior colobomas, amblyopia and refractive error.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
This is a clinical classification of uveitis by the character of the inflammation, and it is useful because it narrows the likely cause and directs investigation. The two patterns differ in their onset, the type of keratic precipitates, the presence of nodules, and their typical causes.
Recognising a uveitis as granulomatous (mutton-fat KPs and iris nodules) should prompt a search for tuberculosis, sarcoidosis, syphilis, VKH or sympathetic ophthalmia, whereas an acute non-granulomatous anterior uveitis points more toward the HLA-B27 spondyloarthropathies or an idiopathic cause.
A NOTE ON HOW THE DISTINCTION GUIDES TREATMENT
Beyond narrowing the cause, the granulomatous/non-granulomatous distinction has practical treatment implications. An acute non-granulomatous anterior uveitis often responds briskly to a course of topical steroids and a cycloplegic and may need no systemic work-up on a first episode. A granulomatous uveitis, by contrast, tends to be chronic, more often bilateral or posterior, and driven by a systemic disease, so it usually requires investigation and frequently systemic steroids or immunosuppression. Thus a single clinical observation at the slit lamp — the character of the KPs and the presence of nodules — meaningfully shapes both how far one investigates and how aggressively one treats.
THE BOTTOM LINE
Classifying uveitis as granulomatous or non-granulomatous from the KPs and nodules narrows the likely cause and shapes both the extent of investigation and the intensity of treatment.
IN PRACTICE
Ultimately the two categories are ends of a spectrum rather than rigid boxes, and some diseases can show features of both; nonetheless, describing a uveitis by this simple clinical character remains one of the quickest ways to prioritise the differential diagnosis at the slit lamp.
In short, it is a rapid, bedside way of triaging a uveitis toward its most likely causes and appropriate work-up, used alongside the anatomical location to build the full clinical classification.
As a final caveat, the character of a uveitis can change over time or with treatment — an initially non-granulomatous picture may become granulomatous, or partly-treated granulomatous disease may look bland — so the classification is reassessed at each visit rather than fixed at the first, and is always interpreted together with the anatomical location and the clinical course.
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KEY POINTS TO REMEMBER
Uveitis is clinically classified as non-granulomatous or granulomatous — this narrows the likely cause.
Non-granulomatous: acute, painful, fine KPs, no nodules; HLA-B27, idiopathic, trauma.