Purpose
How does a patient actually sees once he has been placed an intraocular lens (IOL) is a subjective evaluation sometimes difficult to understand by the clinicians. An objective way to know how an IOL is performing would be to create a schematic eye that could show us with real images how the patient is perceiving those images. Here we present a proposed novel schematic eye where different IOLs can be placed, and images of different targets can be taken in order to objectively analyze them.
Methods
A schematic eye consisting of a optical microscope with a camera, a platform holding the IOL, a diaphragm that simulates the pupil with a range of aperture of 2-5mm, a pattern target (simulating an optotype) and a light source (See figure 1) were arranged so the images taken by the camera could be in focus with the target. In this schematic eye, the target can be lowered, elevated or in a fixed position, in the latter the images stay in focus while opening and closing the diaphragm simulating a pupil, like that, the differences from the same image taken with different diaphragm diameters can be analyzed. Also at the lens position any kind of IOL can be placed. For this study parallel or concentric line targets were used, and a refractive - diffractive - apodized IOL was placed in the schematic eye and images were recorded.
Results
ubjectively with 2 and 3 mm diaphragm diameters, the images were clear in the central and peripheral areas of the image. When the diaphragm was opened wider, the central image lost quality and the peripheral image increased its sharpness. When elevating or lowering the target a similar effect was found, with the peripheral and central image changing in sharpness.
Conclusions
This novel schematic eye is an alternative to study the images produced by different IOLs at variable diaphragm diameters. Images can be analyzed qualitatively and in the future with the appropriate software quantitatively. This schematic eye will help clinicians and researchers to make better analysis of the behavior and performance of optics systems related to cataract surgery, intraocular lenses either focal or multifocal and it variations with pupil size.
Keywords: 567 intraocular lens •
630 optical properties •
667 pupil