Predicting Accommodative Response Using Paraxial Schematic Eye Models.

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Previous ultrasound biomicroscopy (UBM) studies established linear relationships for predicting accommodative optical response (AOR) from biometric changes.
• These predictions had a standard deviation below 0.55D in young and pre-presbyopic populations.

Purpose of the Study:

• To construct paraxial schematic eyes (SE) using measured accommodative ocular biometry.
• To determine if these SE models improve the prediction of AOR compared to previous methods.

Main Methods:

• Ocular biometry parameters were measured using OCT, A-scan, and UBM in 48 subjects (24 young, 24 pre-presbyopic).
• Individual paraxial SEs were constructed for each subject using three lens equivalent refractive index methods.
• Calculated AOR from individual SEs were compared against Grand Seiko (GS) autorefractor measurements.

Main Results:

• A linear relationship was found between SE-calculated and GS-measured AOR (young: r=0.86; pre-presbyopic: r=0.55).
• The mean absolute difference in AOR between GS and individual SEs was 0.50D for both young and pre-presbyopic subjects.
• Average SEs showed a larger mean absolute difference (0.77D for young, 0.51D for pre-presbyopic).

Conclusions:

• Individual paraxial SEs predict AOR with a standard deviation of 0.50D in both young and pre-presbyopic populations.
• This predictive model, while marginally better than linear regressions, comprehensively integrates all ocular biometric parameters.