'Ease of adaptation' predicts preferred spectacle prescriptions better than visual acuity: a retrospective analysis.

Clinical relevance: Factors predicting patient acceptance of a new spectacle prescription need to be determined to make optimal prescribing decisions.

Background: Clinicians usually prescribe for best visual acuity. However, for some patients, a partial change is prescribed to ease adaptation, despite providing suboptimal visual acuity. This study seeks to develop an understanding of which factors predict patient preference between spectacle prescriptions by using a retrospective analysis to compare ease of adaptation, subjective quality of distance vision and optimal distance visual acuity.

Methods: A retrospective analysis utilised a 196-patient data set in which participants wore two prescriptions, one based on the subjective refraction of an optometrist modified by judgement and one on autorefractor results modified for ease of adaptation by an algorithm. Spectacles were worn for 3 weeks each, and participants responded to questions about which prescription they preferred and their quality of distance vision and ease of adaptation (on a 0-10 scale) with each prescription. A logistic regression analysed which variables predicted whether participants responded yes or no to the question 'If you had purchased these spectacles for $100 (US$200 adjusted to 2023 value), would you be happy with them?'

Results: There was a significant difference between the preferred and non-preferred prescriptions for the subjective quality of distance vision rating (medians 9 vs. 8; Z = -7.80, p < 0.0001) and ease of adaptation rating (medians 8 vs. 5; Z = -8.32, p < 0.0001) but the distance binocular visual acuity was not significantly different (both means = -0.09 logMAR; Z = -0.60, p = 0.55). Of all participants, 94% preferred the prescription deemed easier to adapt to but only 59% preferred the prescription with better subjective quality of distance vision and best visual acuity.

Conclusion: Distance visual acuity was not found to be a useful predictor of participant preference to a new prescription and is likely over-relied upon in practice. The results support the adjustment of the subjective prescription where appropriate to aid patient adaptation and comfort.