## Predisposing Factors for Rhegmatogenous Retinal Detachment **Key Point:** High myopia (≥6 diopters) is the single most common predisposing factor for RRD globally and in the Indian population. ### Why High Myopia Increases RRD Risk **High-Yield:** Myopic eyes have the following structural abnormalities: 1. **Increased axial length** — elongation of the globe stretches the retina and vitreous 2. **Posterior staphyloma** — outward bulging of the posterior pole increases tractional forces 3. **Vitreous liquefaction** — myopic eyes undergo earlier and more extensive vitreous degeneration 4. **Retinal thinning** — the retina is stretched over a larger surface area, becoming thinner and more fragile 5. **Lattice degeneration** — more common in myopes; areas of retinal thinning predispose to breaks ### Comparative Risk Profile | Factor | RRD Risk | Mechanism | |--------|----------|----------| | High myopia (>6D) | **Very high** | Axial elongation, vitreous degeneration, retinal thinning | | Lattice degeneration | High | Localized retinal thinning; often secondary to myopia | | Post-cataract surgery | Moderate | Vitreous loss, zonular damage, increased vitreous mobility | | Posterior vitreous detachment | Moderate | Can cause vitreous traction and retinal breaks | | Aphakia | Moderate | Loss of lens support; increased vitreous mobility | **Clinical Pearl:** In India, the prevalence of myopia is rising, making myopic RRD an increasingly common presentation. Myopic patients account for 40–50% of all RRD cases in tertiary eye centers. ### Mnemonic: **MYOPIA** — **M**ost **Y**ielding **O**ptic **P**athology **I**ncreasing **A**detachment risk **Warning:** Do not confuse lattice degeneration (a consequence of myopia) with myopia itself as the primary factor. While lattice is a risk factor, myopia is the underlying predisposing condition. 
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