'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.

Distance spectacle-wearing habits in older patients in England.

PURPOSE: To report the proportion of older people in England who wear distance spectacles full time, part time and rarely, and to investigate factors that influence how much the distance vision (DV) correction is worn. METHODS: A two-part questionnaire investigating the spectacle-wearing habits of older people was developed and completed by 322 participants (age 72 years ±7.7, range 60-94). A subcohort of 209 DV correction wearers with a mean spherical equivalent (MSE) of <±4.00DS was selected for a logistic regression to investigate which factors influence how much the DV correction is used. RESULTS: In total, 43% of emmetropic, and 55% of pseudophakic, DV spectacle wearers wear their correction full time. Lens type, MSE and the age that participants first wore a DV correction significantly predicted DV correction wearing habit (adjusted R2 = 0.36), with lens type being the strongest predicting factor and progressive users wearing their spectacles 37% more than those using single vision lenses. CONCLUSIONS: Many patients appear to consider convenience more important than being spectacle independent at distance, with lens type the most significant influencing factor of how much those with low/moderate refractive error wear their distance correction. Many emmetropes and pseudophakes choose to wear their progressive or bifocal spectacles full time, and the emmetropia provided by cataract surgery does not provide independence from full-time spectacle wear for many patients. The optometrist has a key role in discussing both choice of spectacle lens correction and the refractive outcome options of cataract surgery with patients.

The Visual Impact of Lens-Induced Astigmatism is Linked to Habitual Axis.

PURPOSE: Many studies have assessed the visual impact of astigmatism by inducing it using loose trial lenses at set axes. There are conflicting opinions and some confusion about the results, but the reduction in vision is typically least with lens-induced with-the-rule astigmatism. In this study, we determined whether a participant's habitual astigmatism influences the impact of lens-induced astigmatism on distance visual acuity (VA). METHODS: Participants included 35 adults (age range 19-79, average 41.3 ± 15.4 years), who were either astigmats (≥0.75DC; N = 21) or non-astigmatic controls (N = 14). Distance VA was measured using an automated FrACT (Freiburg VA) system with the participant's habitual correction, and then with the addition of a +1.00DC lens at either 90 or 180 degrees (control) or at and perpendicular to the axis of habitual astigmatism (astigmats). RESULTS: The reduction in VA with induced astigmatism was significantly affected by whether the participant was a with-the-rule astigmat, against-the-rule astigmat, or non-astigmat (p = 0.006). Lens-induced astigmatism axis ≈ 180 (160-20°) reduced the VA less than axis ≈ 90 (70-120°) in the control group (reduction in mean VA of 0.32 SD ± 0.10 with 95% confidence intervals of [0.27,0.37] compared to 0.42 ± 0.09 [0.37,0.47] logMAR) and with-the-rule astigmats (reduction in VA of 0.31 SD ± 0.06 [0.27,0.35] compared to 0.45 SD ± 0.12 [0.38,0.52] logMAR). The against-the-rule astigmats had a very similar reduction in VA with the ≈+1.00DC axis 180 condition compared to the ≈+1.00DC axis 90 condition (reduction in VA of 0.26 SD ± 0.09 [0.21,0.31] compared to 0.25 SD ± 0.14 [0.17,0.33] logMAR). CONCLUSIONS: The impact of lens-induced astigmatism was dependent on the refractive status of the participants. When investigating the impact of lens-induced astigmatism, it is important to consider the participants' habitual axis of astigmatism.