Refractive changes during off-the-axis retinoscopy in myopia

Area of Science:

• Ophthalmology
• Optometry
• Refractive Error Analysis

Background:

• Retinoscopy is a common method for determining refractive error.
• Off-axis measurements may introduce variability in refractive assessment.
• Understanding these variations is crucial for accurate ocular examinations.

Purpose of the Study:

• To investigate the refractive shift during off-axis retinoscopy in myopic patients.
• To quantify the impact of cycloplegic drugs on these measurements.
• To analyze the accuracy of retinoscopy at different eccentricities.

Main Methods:

• Prospective cross-sectional study involving 10 myopic patients with refractive errors ≤ -3.00 D.
• Cycloplegic refraction performed at 0°, 10°, and 20° by a single examiner.
• Statistical analysis using descriptive data and paired t-test for on-axis vs. off-axis comparisons.

Main Results:

• A mean myopic shift of approximately 7% at 10° and 18% at 20° eccentricity was observed.
• Mean spherical equivalent refractions were -2.5495 D (0°), -2.737 D (10°), and -3.0265 D (20°).
• Statistically significant differences (P < 0.05) were found between on-axis and off-axis measurements.

Conclusions:

• Increased eccentricity during retinoscopy induces greater errors in refractive assessment.
• Off-axis measurements can lead to an overestimation of myopia.
• Clinical practice should consider the impact of retinoscopy angle on refractive outcomes.