## Cortical Cataract: Definition and Morphology **Key Point:** Cortical cataracts affect the lens cortex and present with a characteristic white, opaque appearance at the periphery (cortical spokes) while the nucleus remains clear initially, allowing relatively preserved central vision until advanced stages. ### Clinical Features | Feature | Cortical Cataract | Nuclear Sclerotic | Posterior Subcapsular | | --- | --- | --- | --- | | **Location** | Lens cortex (periphery) | Lens nucleus (center) | Posterior lens capsule | | **Appearance** | White spokes radiating from nucleus | Brown/amber discoloration | Granular opacities at posterior pole | | **Vision impact** | Glare, monocular diplopia early | Myopic shift, dim vision | Disproportionate vision loss despite minimal opacity | | **Prevalence** | Most common age-related type | Second most common | Less common | ### Pathophysiology Cortical cataracts develop due to: 1. Osmotic imbalance in cortical lens fibers 2. Influx of sodium and water → fiber swelling and disruption 3. Liquefaction of cortical proteins 4. Formation of cortical "spokes" (radial opacities) **High-Yield:** Cortical cataracts classically cause **glare and monocular diplopia** (from multiple refractive surfaces) early, while central vision remains relatively preserved until the opacity reaches the visual axis. **Clinical Pearl:** Patients with cortical cataracts often report better vision in dim light (pupillary constriction reduces glare) and worse vision in bright sunlight — this is a key diagnostic clue. ### Why Cortical is Most Common Cortical cataracts account for approximately 40–50% of age-related cataracts, making them the most frequent type encountered in clinical practice [cite:Khurana Comprehensive Ophthalmology Ch 7]. 
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