Ocular Evidence
Cohort similarity search

Which published cohorts overlap my inputs?

This retrieves evidence from populations with overlapping reported ranges. It does not predict an individual outcome or assess candidacy.

Follow-upAll reported follow-ups
ProceduresPRK
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May describe a treatment site, institution or author affiliation. Confirm the linked publication before interpreting it geographically.

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No age, sphere or cylinder filter was applied. Results use only the selected procedure, machine, publication-place and follow-up filters.

9 relevant study cohorts

795 observed eyes across matching follow-ups

Compare results

Percentages are results a study reported for its own patients, not a prediction for you. Where a study measured an outcome more than once, the latest matching follow-up is shown. “Not reported” means the study did not publish that number; it does not mean zero.

What do these outcomes mean?Hide what these outcomes mean
20/20 vision or better without glasses

Share of checked eyes that could see 20/20 or better without glasses or contact lenses after treatment.

Within half a diopter of the target

Share of checked eyes that landed within half a diopter of the correction the study aimed for.

Within one diopter of the target

Share of checked eyes that landed within one diopter of the correction the study aimed for.

Dry eye reported

Share meeting that study’s definition of dry eye; questionnaires, tests and thresholds can differ.

Halos reported

Share reporting rings around lights under the questions and symptom threshold used by that study.

Glare reported

Share reporting uncomfortable or scattered brightness under the questions and threshold used by that study.

Starbursts reported

Share reporting rays or streaks around lights under the questions and threshold used by that study.

Corneal haze reported

Share of checked eyes with postoperative corneal haze under the grading threshold and observation window used by that study. Transient and persistent haze are not interchangeable.

Infectious keratitis reported

Share of treated eyes diagnosed with infectious keratitis during the study’s observation window. Case definitions and follow-up duration may differ.

Endophthalmitis reported

Share of treated eyes diagnosed with postoperative endophthalmitis during the study’s observation window. Exact event counts and follow-up are essential for this rare serious event.

Corneal ectasia reported

Share diagnosed with post-surgery corneal weakening during the period that study observed its patients.

Normal OSDI result

Share whose dry-eye questionnaire score fell within the range that study defined as normal; this is not automatically the inverse of a dry-eye diagnosis rate.

Ocular Surface Disease Index (OSDI)

A questionnaire score about dry-eye symptoms and their effect on daily life; lower scores generally mean fewer symptoms.

Tear-breakup time

Seconds before the tear film starts to break apart after a blink; longer times generally indicate a more stable tear film.

Schirmer test

Millimetres of wetting on a paper strip used to assess tear production; testing protocols can differ between studies.

Dry-eye questionnaire score

A patient-reported dry-eye symptom score using the questionnaire selected by that study; scales are not interchangeable.

Filter match

PRK · ALLEGRETTO WAVE EYE-Q

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

Eyes
320
Follow-up
3 months, 6 months, 12 months
Location
United States

How well people saw afterwards

20/20 vision or better without glasses94.5%
294 of 311 eyes · at 12 months · source-reported · Source · 29
Within half a diopter of the target94.5%
294 of 311 eyes · at 12 months · source-reported · Source · 28
Within one diopter of the target99.4%
309 of 311 eyes · at 12 months · source-reported · Source · 28

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

Who the study enrolled: Myopia or myopia with astigmatism treated for elimination of up to -6.0 D spherical equivalent, with up to -6.0 D sphere and up to -3.0 D astigmatism at the spectacle plane.
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PRK

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

Eyes
225
Follow-up
10 years
Location
Spain

How well people saw afterwards

20/20 vision or better without glassesNot reported
Within half a diopter of the targetNot reported
Within one diopter of the target75.0%
169 of 225 eyes · at 10 years · source-reported · Source

Side effects and related measurements

Retreatment rate42.0%
95 of 225 eyes
Reported at/by 10 years
Source

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

Who the study enrolled: Preoperative spherical equivalent between plano and -6.00 D.
Read the publication
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PRK

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

Eyes
103
Follow-up
3 months
Location
Not reported

How well people saw afterwards

20/20 vision or better without glasses94.0%
90 eyes assessed · at 3 months · source-reported · Source
Within half a diopter of the targetNot reported
Within one diopter of the targetNot reported

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

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PRK

Twelve-Month Outcomes of Wavefront-Optimized PRK for High Myopic Correction Compared with Low-to-Moderate Myopia (2021)

Eyes
40
Follow-up
12 months
Location
Thailand

How well people saw afterwards

20/20 vision or better without glasses97.5%
39 of 40 eyes · at 12 months · source-reported · Source
Within half a diopter of the targetNot reported
Within one diopter of the target100.0%
40 of 40 eyes · at 12 months · source-reported · Source

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

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PRK

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

Eyes
35
Follow-up
3 months
Location
Philippines

How well people saw afterwards

20/20 vision or better without glassesNot reported
Within half a diopter of the targetNot reported
Within one diopter of the targetNot reported

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

Who the study enrolled: Adults with myopia and MRSE ≤1.5 D or hyperopia and MRSE ≥+1.5 D.
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Filter match

PRK

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

Eyes
30
Follow-up
6 months
Location
Not reported

How well people saw afterwards

20/20 vision or better without glassesNot reported
Within half a diopter of the targetNot reported
Within one diopter of the targetNot reported

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

Who the study enrolled: Myopia with spherical equivalent at least -2.50 D and 3.00 D cylindrical refractive error.
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PRK

Twelve-Month Outcomes of Wavefront-Optimized PRK for High Myopic Correction Compared with Low-to-Moderate Myopia (2021)

Eyes
29
Follow-up
12 months
Location
Thailand

How well people saw afterwards

20/20 vision or better without glasses89.7%
26 of 29 eyes · at 12 months · source-reported · Source
Within half a diopter of the targetNot reported
Within one diopter of the target100.0%
29 of 29 eyes · at 12 months · source-reported · Source

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

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PRK · AMARIS

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

Eyes
29
Follow-up
12 months
Location
Emmetropia Mediterranean Eye Institute, Heraklion, Crete · Greece

How well people saw afterwards

20/20 vision or better without glassesNot reported
Within half a diopter of the target85.7%
29 eyes assessed · at 12 months · source-reported · Source · Abstract
Within one diopter of the targetNot reported

Side effects and related measurements

Not reported: dry eye, halos, glare, starbursts, haze, keratitis, ectasia.

Who the study enrolled: Matched high-myopia control eyes; myopia greater than 6.00 D with astigmatism below 3.50 D.
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Filter match

PRK

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

Eyes
Not reported
Follow-up
12 months
Location
United States

How well people saw afterwards

20/20 vision or better without glassesNot reported
Within half a diopter of the targetNot reported
Within one diopter of the targetNot reported

Side effects and related measurements

Dry eye reported5.0%
Denominator not reported
Reported at/by 12 months
Source · Abstract — Results

Not reported: halos, glare, starbursts, haze, keratitis, ectasia.