Ocular Evidence
Procedures / PRK
Surface ablation

PRK outcomes

The corneal epithelium is removed to expose the stromal layer, which is then reshaped with an excimer laser.

Source: U.S. Food and Drug Administration
Find overlapping cohorts
8studies represented
9study arms
811reported enrolled eyes*
10 yearslongest standardized follow-up

* Descriptive sum of reported arm counts. Missing eye counts are not treated as zero, and overlapping cohorts may not be additive.

How the operation changes the eye
Three-stage medical illustration showing epithelial removal, excimer laser reshaping, and a bandage contact lens after PRK
Original explanatory illustration. Simplified anatomy; exact devices and technique vary.
How the operation works

The corneal surface is removed, then reshaped

PRK reshapes the front of the cornea directly, without creating a flap.

  1. The surgeon removes the cornea’s thin surface-cell layer, called the epithelium.
  2. An excimer laser removes a planned amount of the exposed tissue to change corneal curvature.
  3. A bandage contact lens usually protects the surface while the epithelium grows back.
Clinical reference: US FDA — PRK patient information booklet

Study-specific outcomes

Percentages are displayed individually. They are not pooled or averaged.

MODERATE evidenceRCTVerified evidence

Transepithelial Versus Conventional PRK: A Randomized Controlled Study (2025)

Conventional PRK35 enrolled eyesDevice not reported
3 months35 eyes observed
Not reportedUncorrected 20/20 or better
Not reportedRefraction within ±0.50 D
Not reportedRefraction within ±1.00 D
Not reportedLost at least 2 lines of CDVA
Additional source-reported outcomes
0.26 DSource
Mean absolute prediction error
MODERATE evidenceRCTVerified evidence

Transepithelial Versus Epithelium-off Photorefractive Keratectomy in High Compound Myopic Astigmatism (2024)

Epithelium-off PRK30 enrolled eyesDevice not reported
6 months30 eyes observed
Not reportedUncorrected 20/20 or better
Not reportedRefraction within ±0.50 D
Not reportedRefraction within ±1.00 D
Not reportedLost at least 2 lines of CDVA
Additional source-reported outcomes
0.67 DSource
Mean residual cylinder
50.0%
15/30 eyes
Source
Residual cylinder within 0.50 D
HIGH evidenceFDA PIVOTALVerified evidence

FDA pivotal clinical study of PRK with the ALLEGRETTO WAVE EYE-Q (2016)

ALLEGRETTO WAVE EYE-Q PRK320 enrolled eyesALLEGRETTO WAVE EYE-Q
3 months317 eyes observed
90.9%
288/317 eyes
Source · 29
Uncorrected 20/20 or better
92.4%
293/317 eyes
Source · 27
Refraction within ±0.50 D
99.4%
315/317 eyes
Source · 27
Refraction within ±1.00 D
0.30%
1/317 eyes
Source · 16
Lost at least 2 lines of CDVA
6 months314 eyes observed
93.0%
292/314 eyes
Source · 29
Uncorrected 20/20 or better
93.3%
293/314 eyes
Source · 27
Refraction within ±0.50 D
99.7%
313/314 eyes
Source · 27
Refraction within ±1.00 D
0%
0/314 eyes
Source · 16
Lost at least 2 lines of CDVA
12 months311 eyes observed
94.5%
294/311 eyes
Source · 29
Uncorrected 20/20 or better
94.5%
294/311 eyes
Source · 28
Refraction within ±0.50 D
99.4%
309/311 eyes
Source · 28
Refraction within ±1.00 D
0%
0/311 eyes
Source · 16
Lost at least 2 lines of CDVA
MODERATE evidencePROSPECTIVE COHORTVerified evidence

Single-Step Transepithelial PRK vs Alcohol-Assisted PRK in Myopia and Compound Myopic Astigmatism Correction (2016)

Alcohol-assisted PRK103 enrolled eyesDevice not reported
3 months90 eyes observed
94.0%
90 eyes
Source
Uncorrected 20/20 or better
Not reportedRefraction within ±0.50 D
Not reportedRefraction within ±1.00 D
Not reportedLost at least 2 lines of CDVA
Additional source-reported outcomes
21.0%
90 eyes
Source
Loss of 1 line of corrected visual acuity
-0.12 DSource
Mean postoperative spherical equivalent
MODERATE evidencePROSPECTIVE COHORTVerified evidence

Chronic dry eye in photorefractive keratectomy and laser in situ keratomileusis: Manifestations, incidence, and predictive factors (2015)

PRK cohortEye count not reportedDevice not reported
12 monthsFollow-up sample not reported
Not reportedUncorrected 20/20 or better
Not reportedRefraction within ±0.50 D
Not reportedRefraction within ±1.00 D
Not reportedLost at least 2 lines of CDVA
Additional source-reported outcomes
Chronic dry-eye incidence
MODERATE evidencePROSPECTIVE COHORTVerified evidence

Single-Step Transepithelial ASLA (SCHWIND) With Mitomycin-C for the Correction of High Myopia: Long-Term Follow-Up (2015)

Alcohol-assisted PRK29 enrolled eyesAMARIS
12 months29 eyes observed
Not reportedUncorrected 20/20 or better
Refraction within ±0.50 D
Not reportedRefraction within ±1.00 D
Not reportedLost at least 2 lines of CDVA
Additional source-reported outcomes
-0.20 D
29 eyes
Source · Abstract
Mean postoperative spherical equivalent
0.060 logMAR
29 eyes
Source · Abstract
Mean uncorrected distance visual acuity
MODERATE evidenceRETROSPECTIVEVerified evidence

Ten-year follow-up of photorefractive keratectomy for myopia of less than -6 diopters (2008)

Myopic PRK225 enrolled eyesDevice not reported
10 years225 eyes observed
Not reportedUncorrected 20/20 or better
Not reportedRefraction within ±0.50 D
75.0%
169/225 eyes
Source
Refraction within ±1.00 D
Not reportedLost at least 2 lines of CDVA
Additional source-reported outcomes
92.0%
207/225 eyes
Source
MRSE within ±2.00 D of target
42.0%
95/225 eyes
Source
Retreatment rate