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Small-aperture intraocular lens tolerance to induced astigmatism

Authors Ang RE

Received 28 April 2018

Accepted for publication 10 July 2018

Published 4 September 2018 Volume 2018:12 Pages 1659—1664

DOI https://doi.org/10.2147/OPTH.S172557

Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Justinn Cochran

Peer reviewer comments 4

Editor who approved publication: Dr Scott Fraser


Robert Edward Ang

Department of Cornea and Refractive Surgery, Asian Eye Institute, Makati City, Philippines

Purpose: This prospective, single-site study aimed to assess the corresponding change in monocular visual acuity with induced astigmatic defocus in subjects implanted with a small-aperture intraocular lens (IOL).
Patients and methods: Ten subjects with a mean age of 65.1 years were recruited. Eleven eyes of these 10 subjects were implanted (9 unilaterally, 1 bilaterally) with an IC-8 small-aperture IOL. Baseline manifest refraction and best-corrected distance visual acuity were measured with a Snellen chart (Tumbling E chart). Astigmatic defocus was induced in the same axis as the manifest sphere-cylinder refraction or at 180° for a spherical refraction. Cylinder defocus was reduced in 0.50 D steps from -2.50 D, and distance visual acuity was measured at each level of defocus.
Results: Mean distance visual acuity was 0.08 logarithm of minimum angle of resolution (logMAR) ±0.08 (20/24) at 1.50 D of defocus, 0.18 logMAR ±0.08 (20/30) at 2.00 D of defocus, and 0.24 logMAR ±0.07 (20/35) at 2.50 D of defocus. Eight out of 10 subjects achieved 20/25 or better vision with 1.50 D of cylinder defocus, and all subjects were 20/30 or better. Ten out of 11 subjects were 20/40 or better with 2.50 D of defocus.
Conclusion: The IC-8 IOL shows good tolerance to astigmatic defocus with minimal effect on visual acuity. Overall, 20/25 or better distance acuity was maintained through 1.50 D cylinder defocus.

Keywords: multifocal intraocular lenses, extended depth of focus lenses, refractive errors, cataract

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