Evaluation of Refractive Measurements Using a Handheld Autorefractor (Retinomax K+ Screen) Versus Streak Retinoscopy...

Area of Science:

• Veterinary ophthalmology
• Ophthalmic diagnostics
• Refractive error assessment

Background:

• Accurate refractive assessment is crucial for diagnosing ocular conditions in dogs.
• Handheld autorefractors offer potential for rapid, non-invasive measurements.
• Evaluating new diagnostic tools is essential for improving veterinary eye care.

Purpose of the Study:

• To compare the accuracy of the Retinomax K+ Screen handheld autorefractor with manual streak retinoscopy in non-cyclopleged dogs.
• To assess the clinical applicability and reliability of the autorefractor for canine refractive error evaluation.

Main Methods:

• Thirty-four dogs (68 eyes) underwent ophthalmic examination and refractive assessment.
• Measurements were obtained using both streak retinoscopy and the Retinomax K+ Screen handheld autorefractor.
• Statistical analyses included Wilcoxon signed-rank test, Bland-Altman analysis, and Spearman's rank correlation.

Main Results:

• Autorefraction was successful in 57 of 68 eyes; 11 were excluded due to poor quality.
• Autorefraction systematically overestimated hyperopia compared to retinoscopy (0.98 D vs 0.13 D).
• Wide limits of agreement (-2.52 to 4.10 D) and moderate correlation (ρ=0.49) indicated substantial variability.

Conclusions:

• The Retinomax K+ Screen provides rapid measurements but overestimates hyperopia in dogs.
• Considerable variability and reduced reliability limit its clinical precision.
• Its use as a screening tool in clinical settings is questionable due to inconsistent results.