Abstract
Purpose :
We aimed to optimise a multifocal power profile (MPP) based on through-focus image quality scores (IQS) of simulated images.
Methods :
Twenty subjects scored the quality of computationally blurred images following a 5-items continuous scale (three high-contrast letters of 0.4 logMAR) through their sphero-cylindrical correction and a 3 mm artificial pupil. Simulated images were calculated from -4 to +2D each 0.25D and for a 4.5 mm pupil diameter using a numerical eye model. Twenty seven MPP were simulated, they differed by the radius from which the power begins to be more positive (2.25/1.87/1.29 mm) and by the position (i.e. Radial Distance (RD) of 2.25/1.87/1.29 mm and Sagittal Power (SP) of 0/0.625/1.25/1.875/2.50 D) of an intermediate point between the last one and a SP of 2.50D in the center of the profile.
Results :
We calculated the ratio between the area of pupil where the SP was lower than 0.5D (i.e. distance area) and the total area of the pupil. We found a high correlation (i.e. R2 = 0,85) between this criterion and the peak of IQS at distance. We also calculated the ratio between the area of pupil where the SP was higher than 1.87D (i.e. near area) and the total area of the pupil. The peak of IQS occuring at near rapidly increased when enlarging the near area and then remained quite unchanged with larger near area. A good near IQS was observed when the near area covered at least around 25% of the pupil. We calculated the area under the through-focus subjective quality of vision curve (AUC) higher than 40 (i.e. level from which the quality of vision becomes acceptable). This criterion was normalised by the naked eye condition (i.e. Profile’s AUC divided by naked eye’s AUC). The 1.87RD1.29SP0.625 profile showed the highest level of total benefit, but this profile was not balanced between the 3 distances of vision (i.e. distance, intermediate and near). The most balanced profiles were 1.87RD1.29SP1.875 and 1.87RD1.29SP2.50. We also measured the width of the through-focus curves (i.e. Depth-of-Focus - DoF) where an acceptable IQS is obtained (i.e. score higher than 40). The best benefit/DoF were observed with 1.87RD1.29SP0.625, 1.87RD1.29SP1.875, 1.87RD1.29SP2.50 and 2.25RD1.87SP0.625.
Conclusions :
The more central area of the pupil is more effective than the periphery. The 1.87RD1.29SP1.875 is the most optimised profile.
This is a 2020 ARVO Annual Meeting abstract.