A 58-year-old Indian woman presents with progressive blurring of vision over 2 years, predominantly affecting her near vision initially. On examination, she has a white opacity in the lens nucleus with a brownish discoloration. The patient reports no history of diabetes, trauma, or prolonged corticosteroid use. Visual acuity is 6/24 in both eyes. What is the most likely type of cataract?

Explanation

## Diagnosis: Nuclear Sclerotic Cataract ### Clinical Presentation The patient presents with: - Progressive vision loss over 2 years (insidious onset) - **Initial presbyopia-like symptoms** (near vision affected first) - White opacity with **brownish discoloration** of the nucleus - No systemic risk factors (diabetes, steroids, trauma) ### Key Features of Nuclear Sclerotic Cataract **Key Point:** Nuclear sclerotic cataracts are the most common type of age-related cataract, accounting for ~50% of all cataracts in the elderly population. | Feature | Nuclear Sclerotic | Cortical | Posterior Subcapsular | |---------|-------------------|----------|----------------------| | **Onset** | Insidious, slow | Variable | Often rapid | | **Initial symptom** | Myopic shift, presbyopia | Glare, dysphotopsia | Difficulty with near vision, reading | | **Appearance** | Brown/amber nucleus | Radial spokes, vacuoles | Plaque-like opacity at posterior pole | | **Progression** | Gradual hardening | Variable | Can progress rapidly | | **Associated factors** | Age | Age, metabolic disease | Steroids, trauma, uveitis | ### Pathophysiology **High-Yield:** Nuclear sclerosis occurs due to: 1. Accumulation of lens proteins in the nucleus 2. Increased density and refractive index of the nucleus 3. Protein cross-linking and denaturation 4. Loss of lens elasticity (presbyopia precedes visual loss) ### Clinical Pearl **Myopic shift phenomenon:** Patients with nuclear sclerotic cataracts often report temporary improvement in near vision ("second sight of the aged") due to increased refractive power of the hardened nucleus—a characteristic feature that helps distinguish this type from others. ### Why Nuclear Sclerotic? The **brownish discoloration** is pathognomonic for nuclear sclerotic cataract and results from oxidation and cross-linking of lens proteins over decades. The insidious 2-year progression and initial presbyopic symptoms are also classic for this type.