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Off-axis edge glare in pseudophakic dysphotopsia
Minas T Coroneo1, Therese Pham, L Stephen Kwok
1Department of Ophthalmology, Prince of Wales Hospital, The University of New South Wales, Sydney, Australia.
Journal of Cataract and Refractive Surgery
|November 8, 2003
Summary
Oblique off-axis light can focus intensely on the nasal edge of intraocular lenses (IOLs), creating glare and potentially disturbing vision. Reevaluating IOL edge design may minimize this pseudophakic dysphotopsia.
Area of Science:
- Ophthalmology
- Optical Engineering
- Visual Optics
Background:
- Pseudophakic dysphotopsia is a visual disturbance often experienced by patients with intraocular lenses (IOLs).
- The edge-glare phenomenon is a common complaint, potentially linked to how light interacts with the IOL periphery.
Purpose of the Study:
- To investigate the optical focusing of oblique, off-axis light at the edge of an intraocular lens (IOL).
- To characterize the contribution of peripheral light focusing to the edge-glare phenomenon in pseudophakic dysphotopsia.
Main Methods:
- Utilized nonsequential optical ray-tracing (OptiCAD) on a model pseudophakic human eye.
- Simulated off-axis light rays incident on the temporal cornea at various angles (0-120 degrees).
- Calculated peripheral light focusing and intensity gains at the IOL and retina.
Main Results:
- Oblique temporal corneal light focused intensely (2.56x gain) on the nasal IOL edge and retina.
- A critical incidence window (71-89 degrees) was identified for this focusing effect.
- Up to three secondary images formed, potentially visible under scotopic conditions, contributing to glare.
Conclusions:
- Off-axis light focusing on the IOL nasal edge creates intense glare sources, potentially impairing vision.
- These findings suggest off-axis light is a significant factor in disability glare.
- IOL edge design requires reevaluation to mitigate dysphotopsia caused by peripheral focusing effects.