Related Experiment Videos
Visual performance requirements for post-PRK police recruits.
Robert J Jacobs1, Peter L Hendicott, Bryre Murphy
1Department of Optometry and Visual Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
Clinical & Experimental Optometry
|December 17, 2002
Summary
New Zealand Police refractive surgery standards were tested. Low luminance visual acuity limits were found to be more lenient than previously estimated, with two post-photorefractive keratectomy applicants failing this specific test.
Area of Science:
- Ophthalmology
- Optometry
- Vision Science
Background:
- New Zealand Police regulations permit unaided visual acuity of 6/12 post-refractive surgery.
- Eligibility requires normal performance in glare disability, contrast sensitivity, and low luminance visual acuity tests, one year post-surgery.
- Exclusions include radial keratotomy and keratoplasty.
Purpose of the Study:
- To validate the established visual performance limits for refractive surgery applicants.
- To assess the effectiveness of current New Zealand Police standards for post-photorefractive keratectomy (PRK) applicants.
- To determine normative data for glare disability, contrast sensitivity, and low luminance visual acuity.
Main Methods:
- Eighty healthy young adults underwent tests for glare disability, contrast sensitivity, and low luminance visual acuity to establish 95% confidence limits.
- Thirty-four police applicants who had undergone PRK were evaluated using the same criteria.
- Tests included the Mentor Brightness Acuity Tester, Melbourne Edge Test, and Bailey-Lovie charts under varying contrast and luminance conditions.
Main Results:
- Established 95% confidence limits for normal performance: glare disability (≤10 letters loss), contrast sensitivity (≤12 letters difference, edge contrast ≥20 dB).
- Determined a 95% confidence limit for low luminance visual acuity of 24 letters loss (approx. 5 lines).
- Two of 34 post-PRK applicants failed: one for uncorrected acuity, another for low luminance visual acuity, not glare or contrast sensitivity.
Conclusions:
- The established confidence limits for glare disability and contrast sensitivity align with current police standards.
- The 95% confidence limit for low luminance visual acuity is significantly wider (approx. 5 lines loss) than previously estimated from literature.
- Current standards appear adequate, with low luminance visual acuity being a critical factor for post-PRK police applicants.