Comparing Autorefractors for Measurement of Accommodation

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Accurate measurement of accommodative response is crucial for diagnosing and managing refractive errors and binocular vision anomalies.
• Autorefractors are widely used tools for objective refraction, but their performance in measuring dynamic and static accommodation can vary.
• Understanding the differences between autorefractors like the WAM-5500 and PowerRef-II is important for clinical decision-making.

Purpose of the Study:

• To compare the static and dynamic accommodative responses measured by the WAM-5500 and PowerRef-II autorefractors.
• To evaluate the agreement between subjective refraction and objective measurements from both instruments.

Main Methods:

• Monocular static and dynamic accommodative responses were measured in 30 pre-presbyopic individuals using the WAM-5500 and PowerRef-II.
• Static measurements involved spherical equivalent determination at 0.00, 2.50, and 5.00 diopters (D) of accommodative stimulus.
• Dynamic measurements assessed accommodation and disaccommodation velocities during vergence changes, with PowerRef-II data analyzed at 5 Hz and 25 Hz sampling frequencies.

Main Results:

• Static measurements showed good agreement between subjective refraction and WAM-5500 (0.07 ±0.21 D), but less agreement with PowerRef-II (0.70 ±0.47 D) at distance.
• Differences between instruments were not significant at 2.50 D static stimulation but were significant at 5.00 D (-0.32 ±0.48 D).
• The PowerRef-II, particularly at 25 Hz, recorded significantly faster mean and peak velocities for accommodation and disaccommodation compared to the WAM-5500.

Conclusions:

• The WAM-5500 demonstrates good agreement with subjective refraction for static accommodation.
• The PowerRef-II tends to produce more hyperopic static results and captures faster dynamic accommodative responses, likely due to its higher sampling frequency.
• Clinical use of the PowerRef-II should consider its higher sensitivity to dynamic changes and potential for more hyperopic static readings.