Evaluation of the Quality of Peripheral Fundus Images Observed through a Goldmann 3-Mirror Type Contact Lens Using a Slit-Lamp Microscope

Abstract

Abstract: : Purpose: To evaluate the quality of the peripheral fundus images in pseudophakic eyes observed through a Goldmann 3-mirror type contact lens using a slit-lamp microscope. Methods: Simulated geometric point spread functions (geometric PSFs) and modulation transfer functions (MTFs) of peripheral fundus images in three wavelengths (C-line, 656.27 nm; E-line, 546.07 nm; F-line, 486.13 nm) that were to be observed through a Goldmann 3-mirror type contact lens with a slit-lamp microscope (SL-7F; Topcon, Japan) were calculated from optical data using the ray-tracing method. That calculation is based on the model eye of LeGrand in which the lens is replaced with a standard intraocular lens (20-D, polymethylmethacrylate, 6.0 mm diameter). Estimated astigmatism by the geometric PSF and MTF profiles in X and Y directions were compared with those aberrations corrected with supplementary systems using variable cross-cylinder (VCC) lenses for astigmatism in the slit-lamp microscope. Results: Oblique astigmatism and other aberrations were induced to significantly degrade the quality of the fundus images. Estimated spot diagrams were substantially, but not completely, improved by correction of the astigmatism with VCC lenses. Conclusions: Oblique aberrations including astigmatism degrade the quality of peripheral fundus images observed through a Goldmann 3-mirror type contact lens in pseudophakic eyes. The quality of the fundus images might be improved by correction of the astigmatism.

Keywords: vitreoretinal surgery • laser • optical properties