Intra-examiner repeatability and agreement in accommodative response measurements

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Clinical measurement of accommodative response (AR) is crucial for understanding visual function.
• Determining the repeatability of AR measurements is essential for reliable clinical assessment.
• Several methods exist for measuring AR, including retinoscopy and autorefractometry.

Purpose of the Study:

• To assess the intraexaminer repeatability of four clinical methods for measuring AR: Nott retinoscopy, monocular estimate method (MEM) retinoscopy, binocular crossed cylinder (BCC) test, and near autorefractometry.
• To evaluate the agreement between AR measurements obtained using these different clinical techniques.

Main Methods:

• Sixty-one visually normal subjects (mean age 19.7 years) underwent repeated AR measurements of the right eye at 2.50 D accommodation.
• The Bland-Altman method was used to estimate intraexaminer repeatability (coefficient of repeatability, COR) and agreement (coefficient of agreement, COA).
• Mean differences (MD) and 95% limits of agreement were calculated for each method.

Main Results:

• Nott retinoscopy (-0.10 +/- 0.66 D) and BCC (-0.05 +/- 0.75 D) demonstrated the best intraexaminer repeatability with the lowest mean differences and narrowest limits of agreement.
• Overall limits of agreement across all methods ranged from +/- 0.92 to +/- 1.00 D, considered clinically significant.
• Dynamic retinoscopy techniques (Nott and MEM) showed better agreement (COA = +/-0.64 D), but MEM exhibited low repeatability (COR = +/-0.98 D).

Conclusions:

• Nott retinoscopy is the most suitable method for clinical assessment of AR due to its high repeatability.
• The BCC technique is also a repeatable and recommended method for clinical practice.
• Despite good agreement between Nott and MEM retinoscopy, poor agreement among other methods precludes their interchangeable clinical use.