A patient reports glare and halos after multifocal IOL implantation. This dysphotopsia is primarily caused by:

• A Incorrect IOL power selection causing residual myopia
• B Posterior capsule opacification reducing optical clarity
• C Light energy split between multiple focal points by diffractive or refractive rings creating concentric interference patterns that reduce contrast sensitivity ✓
• D IOL decentration causing prismatic effects

Explanation

Multifocal IOLs (diffractive or refractive types) split incoming light between two or more focal points (near, intermediate, distance). This splitting means that at any given fixation distance, light intended for other focal distances reaches the retina as defocused light — creating concentric rings of out-of-focus light that manifest as halos and glare, particularly in low-luminance/high-contrast conditions (e.g., oncoming headlights at night). Contrast sensitivity is also reduced compared to monofocal IOLs. Posterior capsule opacification causes diffuse glare rather than the characteristic concentric haloing pattern. Decentration causes coma-type aberrations.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.