Abstract
Purpose: :
Generally, visual field measurement is performed by fixing the subject’s eyes on the center of a bowl-shaped instrument called a perimeter placed 30-33 cm in front of the subject, using visual correction if necessary, so the projected area is clearly seen. There was a difference in the light field area between younger individuals with amplitude of accommodation and middle-aged individuals without it. Furthermore, the influence of aberration on peripheral vision may result in larger point images being formed on the retina, which may cause a difference in the measured threshold. In the present study, we investigated point spread function (PSF) of central and peripheral vision in eyes with various optical systems by comparing perimetry measurements of young eyes, eyes with presbyopia, eyes that received laser in situ keratomileusis (LASIK) and eyes with intraocular lenses.
Methods: :
The subjects were a female in her 20s with uncorrected vision of 1.2, a female in her 20s who had received LASIK, two males with presbyopia in their 40s and 50s, and a female in her 50s with intraocular lenses. Using a PSF-1000 (TOPCON Co.), a different diameter double-pass PSF with 1.3 mm of incidence diameter, 3.0 mm and 4.0 mm of output diameter was measured in 0.25D steps to obtain single-pass PSF. The measurement sites were the center and 10, 20, 30, 40 and 45 degrees horizontally from the temporal and nasal sides.
Results: :
The astigmatism and coma aberration in the peripheral vision were remarkably larger in the eyes that received LASIK and the eyes with intraocular lenses than in the young or presbyopic eyes. Furthermore, the object distances in which the circle of least confusion was obtained in the center of the field of the eyes with IOL and the eyes that received LASIK were -2.0D and -1.0D respectively, which of in the temporal 40 degrees were -4.0D and -5.0D respectively.
Conclusions: :
In peripheral vision, there were astigmatism and coma aberrations, and the point images that were projected onto the retina differed depending on the measurement sites. It was suggested that the aberration influenced the results of threshold measurements in the peripheral vision.
Keywords: aberrations • visual fields • imaging/image analysis: clinical