A 68-year-old patient undergoes uncomplicated phacoemulsification with posterior chamber IOL implantation. Six weeks later, he complains of halos and glare at night, especially with oncoming headlights. The IOL used was a diffractive multifocal IOL. The most appropriate counselling is:
- A Halos indicate posterior capsular opacification requiring Nd:YAG laser capsulotomy immediately
- B This is cystoid macular oedema and requires topical NSAIDs
- C The halos are likely permanent optic side effects inherent to diffractive multifocal IOL design and occur due to light energy split between distance and near focal points ✓
- D IOL exchange with a monofocal lens is the first-line treatment
Explanation
Diffractive multifocal IOLs split incoming light into multiple focal points (typically far and near), inherently sacrificing some optical quality at each focal point. This creates dysphotopsia — halos around lights at night due to unfocused rings of light energy. These symptoms are most pronounced in the first 3–6 months; neuroadaptation over months leads to reduced perception for most patients. Patients must be counselled pre-operatively. PCO would cause progressive blurring rather than selective glare; CME causes central blurring; IOL exchange is reserved for severe, unresponsive cases after neuroadaptation failure.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.