Effect of Astigmatism on Apparent Accommodation in Pseudophakic Eyes

Abstract

Eyes with smaller pupil diameter and eyes with greater corneal multifocality are more predisposed to have greater apparent accommodation. However, from clinical and optical viewpoints, corneal or refractive astigmatism does not significantly contribute to apparent accommodation after cataract surgery, suggesting that it may be of less significance that the astigmatism is consciously retained in consideration of this accommodation in astigmatic eyes.

Apparent accommodation in pseudophakic eyes with refractive against-the-rule, with-the-rule and minimum astigmatism

“…In 1983, Nakazawa and Ohtsuki2 reported that pupil diameter was the most important factor in apparent accommodation; smaller pupils were associated with greater apparent accommodation in pseudophakic eyes. In a larger study with 62 pseudophakic eyes, Kamiya et al 4 also confirmed that pupil diameter was the most relevant variable to apparent accommodation using multivariate analysis. Although these previous studies did not investigate the influence of different astigmatism axis orientation, our results demonstrated similar tendency in eyes with ATR astigmatism.…”

“…Nawa et al 3 compared the results of apparent accommodation measurements using 20/20 or 20/30 near vision optotypes, and demonstrated that apparent accommodation decreased when a smaller optotype was used. Kamiya et al 4 measured mean apparent accommodation using a 20/20 near vision optotype, and reported values of 1.58±0.65 D. In contrast, Elder et al ,1 Fukuyama et al 9 and Oshika et al 10 measured mean apparent accommodation with a 20/30 near vision optotype, and found values of 2.72±1.10, 2.00±0.92 and 2.03±0.93 D, respectively. In the present study, we used a 20/30 optotype, and obtained apparent accommodation of 2.53±1.38 D in whole patients, which is in good agreement with the results of previous studies.…”

“…There have been several other reports on the significant relationship between corneal multifocality and apparent accommodation in pseudophakic eyes 4 9 10. Furthermore, in the stepwise multiple regression analysis, corneal multifocality was selected as the most relevant variable, followed by trefoil RMS.…”

“…Corneal astigmatism and topography were obtained using a corneal topographer (TMS-4 Advance; TOMEY Co, Nagoya, Japan). Within the subjects’ pupillary area, the difference between the maximum and minimum corneal optical power was calculated and recorded as the refractive gradient of the cornea, which was used as an index of corneal multifocality 4 9 10. The near point of apparent accommodation was determined in each eye using an accommodometer (HS-9G; KOWA Co, Nagoya, Japan), while the fellow eye was occluded.…”

“…There has been a general belief that astigmatism adds depth of focus and broadens the range of clear vision, and several studies reported a significant relationship between myopic astigmatism and apparent accommodation in pseudophakic eyes 5–8. In contrast, other studies contradicted such a relationship 4 9–11. Thus, the role of astigmatism in apparent accommodation in pseudophakic eyes remains controversial.…”