Q2 LONG ANSWER 10M ★ High-yield

Describe senile cataract with its types, stages, clinical features and complications.

Ophthalmology · 3rd Professional

Types of Age-related Cataract

Type	Features and symptoms
Nuclear sclerotic	Progressive hardening and yellowing of the nucleus, becoming amber, brown (brunescent) and finally black (cataracta nigra). Causes a rise in refractive index and therefore index myopia — producing the phenomenon of "second sight", in which an elderly presbyope finds they can read without glasses again. Distance vision fails first; colours are desaturated and the world looks yellow-brown. Vision is often better in dim light.
Cortical (cuneiform)	Wedge-shaped ("cuneiform") radial spoke-like opacities beginning at the periphery and pointing toward the centre, with water clefts and vacuoles. Because the opacities are peripheral, central vision is preserved until late; the dominant symptom is glare, especially from oncoming headlights at night, and monocular diplopia or polyopia from irregular refraction through the clefts
Posterior subcapsular (cupuliform)	A granular, plaque-like opacity in the central posterior cortex, immediately in the visual axis. Therefore causes early and disproportionate visual loss for its size. Characteristically worse in bright light and for near work — because the pupil constricts and the opacity occupies the whole aperture. Occurs in younger patients, and is the type associated with steroids, diabetes, uveitis, radiation and high myopia
Anterior subcapsular	Beneath the anterior capsule; follows anterior uveitis, chlorpromazine, amiodarone and miotics
Christmas-tree (polychromatic)	Needle-like refractile polychromatic deposits in the deep cortex; associated with myotonic dystrophy

The Three Types of Age-related Cataract Compared

Feature	Nuclear	Cortical	Posterior subcapsular
Site	Central nucleus	Peripheral cortex, spreading inward	Central, immediately in front of the posterior capsule
Age group	Elderly	Elderly	Younger patients
Effect on refraction	Index myopia — "second sight"	Little, until advanced	Little
Vision affected first	Distance	Preserved until late; glare is the complaint	Near and reading, early and disproportionately
Effect of light	Better in dim light (pupil dilates around the nucleus)	Worse with oncoming headlights at night	Worse in bright light and for near (pupil constricts onto the opacity)
Characteristic symptom	Colour desaturation; second sight	Glare; monocular polyopia	Early loss of reading vision out of proportion to the appearance
Associations	Age, smoking, myopia	Age, ultraviolet exposure, diabetes	Steroids, diabetes, uveitis, radiation, high myopia, vitrectomy
Appearance	Yellow to brown (brunescent) to black	Radial cuneiform spokes and water clefts	Granular plaque at the posterior pole, best seen on retroillumination

Stages of Cortical Cataract

1.
Incipient (early) — lamellar separation, water clefts and vacuoles; wedge-shaped cuneiform opacities at the periphery, or a saucer-shaped cupuliform opacity posteriorly.
Vision is minimally affected unless the opacity is posterior and axial → 2.

Symptoms, Signs and Assessment

Symptoms — painless, progressive, painless loss of vision, which is the cardinal feature; glare and difficulty with oncoming headlights; coloured haloes, which have to be told apart from those of glaucoma; monocular polyopia or diplopia, which persists on covering the other eye and is diagnostic of a lenticular cause; frequent changes of spectacles; "second sight" in nuclear cataract; loss of contrast and colour desaturation; and black spots that do not move with eye movement, unlike vitreous floaters
Signs — reduced acuity not improving with a pinhole beyond a point; a dull or absent red reflex on distant direct ophthalmoscopy, with the opacity seen as a black shadow against the red glow; the opacity itself on slit-lamp examination after dilation; and leucocoria in a mature cataract
Preoperative assessment of the posterior segment is essential, because the outcome depends on the retina and optic nerve rather than on the lens: perception of light with accurate projection of rays in all four quadrants; pupillary reactions with a careful search for a relative afferent pupillary defect, which if present indicates optic nerve or extensive retinal disease and a poor prognosis; and, where the fundus cannot be seen, a B-scan ultrasound to exclude retinal detachment, vitreous haemorrhage and a mass

Complications of Untreated Cataract

Complication	Mechanism
Phacomorphic glaucoma	The intumescent swollen lens pushes the iris forward, causing pupil block and acute angle closure. Presents as acute angle-closure glaucoma with a cataract; treated medically and then by urgent lens extraction
Phacolytic glaucoma	In a hypermature lens, high-molecular-weight lens protein leaks out through an intact capsule; macrophages engorged with protein then CLOG the trabecular meshwork. An open-angle glaucoma with a deep anterior chamber, no keratic precipitates and no synechiae. Treated by lens extraction
Phacoantigenic (phacoanaphylactic) uveitis	After the capsule ruptures, exposed lens protein — to which the body is not tolerant — provokes a zonal granulomatous inflammation
Subluxation or dislocation	Zonular weakness in a hypermature sclerotic lens
Uveitis and secondary glaucoma	From chronic leakage of lens material

These complications are the reason not to let a cataract go to hypermaturity — the older teaching of "waiting until it is ripe" belongs to the era of intracapsular surgery, and is now actively harmful.
Iris shadow present means immature and absent means mature, and the test takes seconds with an oblique slit beam
Second sight signals a developing nuclear cataract, and an elderly patient reading without glasses again should be examined

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