Registration tolerance of a custom correction to maintain visual acuity

Area of Science:

• Ophthalmology
• Optical Engineering
• Vision Science

Background:

• Wavefront-guided (WFG) correction offers personalized vision correction.
• Accurate alignment (registration) is critical for WFG device efficacy.
• Understanding tolerance limits prevents unintended visual acuity loss.

Purpose of the Study:

• Develop a predictive model for WFG correction registration tolerance.
• Quantify the relationship between alignment errors and visual acuity changes.
• Demonstrate the model's utility in keratoconic eyes.

Main Methods:

• Plotted log visual Strehl change against translation error for WFG correction rotations.
• Defined contour lines for predicted one- and two-line visual acuity losses.
• Validated the model by comparing predicted vs. measured acuity loss from residual wavefront errors.

Main Results:

• The predictive model accurately estimated acuity changes (R² = 0.91).
• Optical tolerance to movement was asymmetric and dependent on specific optical errors.
• Registration error impact varied with wavefront error, WFG design, and alignment precision.

Conclusions:

• Log visual Strehl changes predict registration tolerance for stable acuity.
• Tolerance limits are specific to each wavefront error and WFG design.
• This model aids in optimizing WFG correction alignment protocols.