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Na, Choi, Yang, Lee, and Kim: The Relationship Between Asphericity and Visual Acuity After Wearing Reverse-Geometry Lens
Original Article

J Korean Ophthalmol Soc 2009;50(5):670-676.

Published online: 7 September 2009

DOI: https://doi.org/10.3341/jkos.2009.50.5.670

The Relationship Between Asphericity and Visual Acuity After Wearing Reverse-Geometry Lens

Jung Hwa Na, MD, Jeong Hoon Choi, MD, Ji Wook Yang, MD, Young Chun Lee, MD, Su Young Kim, MD

Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Korea

Address reprint requests to Su Young Kim, MD Department of Ophthalmology, Uijengbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea #65-1 Geumo-dong, Uijeongbu 480-717, Korea Tel: 82-31-820-3587, Fax: 82-31-847-3418, E-mail: cassiopeia@catholic.ac.kr

Received 13 June 2008       Accepted 10 February 2009

Copyright © 2009 Korean Ophthalmological Society

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To report the change of corneal asphericity and the relationship between asphericity and visual acuity after wearing the reverse-geometry lens.

Methods

The authors reviewed outpatient records of 37 consecutive patients wearing reverse-geometry lenses. The patients were followed up from July 2004 to December 2007. The unaided visual acuity (VA), spherical equivalent (SE) and asphericity before and after wearing the lens were compared. The relationship of SE and final VA, initial astigmatism and final VA, and asphericity and final VA was also analyzed. In addition, the relationship between the increment of VA and asphericity was determined.

Results

VA and SE improved and the asphericity decreased after wearing the lens (p＜0.05). There was high correlation between the spherical equivalent and final visual acuity (p＜0.001), and no correlation between asphericity and final visual acuity (p=0.358) was observed. However, the lower the initial asphericity, the greater the increment of visual acuity observed (p=0.048).

Conclusions

Initial corneal asphericity can be a predictor of increment of VA after wearing reverse-geometry lenses.

Keywords: Corneal asphericity, Corneal eccentricity, Orthokeratology, Reverse-geometric lens, Spherical equivalent

References

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Figure 1.
The relationship of the initial SE and the final VA. This graph shows that the eyes are more myopic, the visual acuity is worse.
jkos-50-670f1.tif
Figure 2.
The relationship of the final SE and the final VA. This graph closely resembles the figure 1. Similarly the myopia is more severe, the visual acuity is worse.
jkos-50-670f2.tif
Figure 3.
The relationship of the initial astigmatism and the final VA. This graph illustrates that the astigmatism is higher, the final visual acuity tends to be lower.
jkos-50-670f3.tif
Figure 4.
The relationship of the initial asphericity and the final VA. Initial asphericity did not affect the final visual acuity.
jkos-50-670f4.tif
Figure 5.
The relationship of the final asphericity and the final VA. The final asphericity did not have an effect on final visual acuity.
jkos-50-670f5.tif
Figure 6.
The relationship of the initial asphericity and the increment of VA. As the initial asphericity was lower, the increment of visual acuity was higher.
jkos-50-670f6.tif
Figure 7.
The relationship of the final asphericity and the increment of VA. The lower the final asphericity, the higher the increment of visual acuity.
jkos-50-670f7.tif
Table 1.
Demographics of patients
Variables Patients
N (Eyes) 37 (68)
Male /Female 7/30
OD/OS 35/33
Age (SD) 16.9 (7.63)
Median (Range) 15.0 (7.0∼32.0)
Follow up months (SD) 9.2 (6.7)
Median (Range) 8.0 (1.0∼31.0)
Table 2.!
Comparison of the unaided visual acuity, spherical equivalent and asphericity
Variables Before wearing lens After wearing lens p-value
Visual acuity (SD) (LogMAR) 1.02 (0.34) 0.05 (0.15) 0.000
Median (Range) 1.10 (0.30∼1.52) 0.00 (0.00∼0.82)
Spherical Equivalent (SD) (D) −3.47 (1.73) −0.64 (0.70) 0.000
Median (Range) −3.25 (−7.25∼-1.00) −0.38 (−2.88∼0.00)
Asphericity (SD) −0.34 (0.14) −0.40 (0.19) 0.023
Median (Range) −0.36 (−0.60∼-0.01) −0.40 (−0.87∼-0.01)

The visual acuity and myopia improved after wearing the lens. The asphericity decreased after lens wearing. This result means that the eyes become more prolate after wearing the reverse-geometry lens.

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