Analysis of the relation between facial asymmetry and users' preference between standard versus customized inset progressive addition lenses

Abstract

Aims/Purpose: User adaptation to progressive addition lenses (PALs) wear requires accurate facial measurements, mainly naso or interpupillary distances, usually measured with a frame ruler. But facial asymmetries are usually ignored. Measurement of foveal fixation axis (FFA) ‐the line linking directly the fixation point and the fovea‐ allows precise facial asymmetry assessment. This study aimed to compare users' preference between standard versus customized inset PALs in patients with and without facial asymmetry according to their FFA measurement.Methods: A crossed, double blind, randomized study was conducted. Participants were classified according to previous experience with PALs (neophytes, PALs users, dropout, and uncomfortable PALs users) and with (>1.0 mm) or without (≤1.0 mm) facial asymmetry. After a complete eye test, two different PALs (LifeStyle 3i, Hoya) were prescribed in a randomized and masked order (2.5 mm standard inset and FFA customized inset PALs). PAL users' preference between both lenses was collected (subjective opinion) after 30 days of wear. Statistical analysis was performed using SPSS 26 (Chicago, USA). ANOVA was used to compare different groups and Chi‐square was used to analyse the frequency of choice of both PALs.Results: 71 participants (37 women and 34 men) were included. 49 with FFA asymmetry; 56% of them (95%CI 42–71%) preferred customized inset lens (Figure 1) (p = 0.05), in dropout group 67% (95%CI 33–100%). No differences (p > 0.05) in clinical parameters were found between patients with or without FFA asymmetry.Conclusions: Participants with FFA asymmetry preferred customized inset lens, especially dropout patients. Facial asymmetry could be a relevant factor in PALs adaptation and FFA measurement could improve users' satisfaction with customized PALs in patients with facial asymmetry.FIGURE 1 (Left). PALs choice according to the patients' facial asymmetry. (Right). PALs choice according to the patients previous use of PALs.imageFIGURE 1 (Left). PALs choice according to the patients' facial asymmetry. (Right). PALs choice according to the patients previous use of PALs.