Korean J Ophthalmol.  2017 Feb;31(1):16-24. 10.3341/kjo.2017.31.1.16.

Clinical Outcomes of an Optimized Prolate Ablation Procedure for Correcting Residual Refractive Errors Following Laser Surgery

• Chung B
• Lee H
• Choi BJ
• Seo KR
• Kim EK
• Kim DY
• Kim TI

• KMID: 2368674
• DOI: http://doi.org/10.3341/kjo.2017.31.1.16

Abstract

PURPOSE
The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery.
METHODS
We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months.
RESULTS
Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured.
CONCLUSIONS
The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.

Keyword

Optimized prolate ablation; Refractive surgery; Residual refractive errors

MeSH Terms

Coma
Humans
Keratectomy, Subepithelial, Laser-Assisted
Keratomileusis, Laser In Situ
Laser Therapy*
Phosmet*
Photorefractive Keratectomy
Refractive Errors*
Refractive Surgical Procedures
Treatment Outcome
Visual Acuity
Phosmet

Figure

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  Fig. 1 Postoperative stability of refractive errors. D = diopters; Preop = preoperative.

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  Fig. 2 Postoperative changes in spherical equivalent of manifest refraction. Preop = preoperative; D = diopters.

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  Fig. 3 Postoperative changes in spherical equivalent of manifest refraction. Preop = preoperative; D = diopters.

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  Fig. 4 Postoperative changes in astigmatic error of manifest refraction. Preop = preoperative; D = diopters.

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  Fig. 5 Postoperative distribution of uncorrected visual acuity. Preop = preoperative; VA = visual acuity.

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  Fig. 6 Attempted versus achieved postoperative spherical equivalent. D = diopters.

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  Fig. 7 Postoperative changes in ocular aberrations. (A) Total ocular HOA RMS, (B) ocular and corneal spherical aberration, (C) total coma aberrations, (D) total trefoil aberrations. HOA = higher-order aberration; RMS = root mean square; Preop = preoperative; SA = spherical aberration. *p < 0.05. All aberrations are reported for a 6.0-mm pupil plotted to the eighth Zernike order. Root-mean-square values are reported.

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