Abstract
Purpose :
To introduce and validate a new system and methodology to evaluate photic phenomena (halos, glare and starbursts) induced by different intraocular lens (IOL) technologies using a “see-through” IOL analyzer system in phakic subjects.
Methods :
The IOL Telescope Type 1 (IT1) system allows subjects to look through the optics of an IOL. It consists of an eye model into which an IOL is loaded and then attached to a system of relay optics that allows a subject to “look through” the IOL and view a scene including any photic phenomena induced by the IOL.
Twenty subjects looked through the IT1 system under different conditions. Five different IOL designs with different clinical levels of photic phenomena were evaluated by the subjects.
Subjects performed the following tests: First, a subjective rating of the level of bother perceived in a natural scene with a central glare source. After, a ring test was conducted where the size of a ring was adjusted to match the size of the veiling luminance perceived by the subject around the glare source. Two brightness levels were used for the rings, one brighter (Inner) and one dimmer ring (Outer).
The results of this study were compared to the clinical outcomes of the subjective perception of halo, glare and starbursts of implanted cataract patients.
Results :
The outer ring test provided results that were well correlated with the clinical questionnaire levels of halo (R2= 0.97), glare (R2=0.99) and starbursts (R2=0.81) bother. The inner ring test showed much lower correlation with the clinical levels (R2 < 0.48). Correlations between subjective grading and clinical responses were strongly dependent on the luminance level of the glare source and the photic phenomena evaluated, being R2=0.72 in the best of cases.
Conclusions :
The results of this study show that the IT1 system can be used to simulate photic phenomena induced by different IOL technologies in phakic eyes. Certain quantitative methods showed a high correlation with the subjective perception of photic phenomena found in cataract patients implanted with the same IOL models.
However, exact conditions under which the tests are performed (glare source brightness, scene selection/brightness, subject expectations/variability) can have large effects on test results. The exact visual experience of an implanted subject may not directly map onto the subjective impression in this and similar “see-through” systems.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.