Cortical Cataract

Cortical cataract is opacification of the lens cortex, appearing as spoke like or wedge shaped opacities from the periphery toward the centre.

• Mechanism: disruption of lens fibre membranes and ion balance (calcium influx, protein loss), with hydration and vacuolation of the cortical fibres.
• Risk factors: ultraviolet B exposure, diabetes, hypocalcaemia, high sodium diet, dehydration episodes, family history, steroid use, and Fabry disease.
• Frequently coexists with nuclear and subcapsular opacities.
• Stages: incipient (vacuoles and water clefts), immature, mature (total opacity), and hypermature (liquefied cortex with a Morgagnian nucleus, leakage of proteins).

• Glare, haloes and visual disturbance from light scatter by the peripheral spokes, often while central acuity remains good; difficulty at night and with oncoming headlights.
• Monocular diplopia, particularly in early disease.
• Visual loss is slow until the spokes reach the visual axis.
• Slit lamp and retroillumination: dark spokes against the red reflex; water clefts and vacuoles; cortical opacity progression to a white lens.
• Hypermature cataract: wrinkled anterior capsule, sinking nucleus, and risk of phacolytic glaucoma (macrophages blocking the trabecular meshwork), inflammation and rupture.

• Visual acuity in bright and dim light, glare testing, contrast sensitivity.
• Retroillumination photography and LOCS III cortical grading (C1 to C5).
• Slit lamp for capsule integrity, zonular weakness (common in hypermature stages), and anterior chamber depth.
• Intraocular pressure and gonioscopy, especially with swollen or hypermature lens.
• Check for diabetes (glucose and HbA1c) and calcium disorders when opacities are bilateral and early.

• Optical measures: spectacles, anti-glare coatings, brimmed hats, ultraviolet blocking sunglasses (UV-protective lenses).
• Surgery when glare or visual loss interferes with function; hydrodissection and hydrodelineation, then complete aspiration of cortex using bimanual or coaxial irrigation aspiration, with careful attention to cortical clean up to prevent posterior capsule opacification.
• Mature or hypermature (white) cataract: trypan blue 0.06 percent capsule staining, a small capsulorhexis with extra care, use of dispersive viscoelastic to pressurise the bag, and capsular tension ring when zonules are weak. Early surgery avoids the complications.
• Phacolytic glaucoma: reduce pressure first (timolol 0.5 percent twice daily, dorzolamide 2 percent three times daily, brimonidine 0.2 percent twice daily, acetazolamide 250 to 500 mg orally or 500 mg intravenously), topical steroid (prednisolone acetate 1 percent every 2 hours), then urgent cataract extraction.
• Control diabetes and correct calcium disorders.
• Postoperative regimen: prednisolone acetate 1 percent four times daily tapered over 4 weeks, NSAID drops, antibiotic drops.