Evaluating the visual benefits of toric soft contact lenses using a novel pupil-controlled vision testing system

Cont Lens Anterior Eye. 2025 Apr;49(2):102604. doi: 10.1016/j.clae.2025.102604. Epub 2026 Jan 23.

ABSTRACT

PURPOSE: This study investigated the clinical astigmatism threshold at which toric soft contact lenses (CLs) provide superior visual acuity (VA) compared with spherical CLs, and how pupil size affects this. A novel pupil-controlled vision testing system (PUCS) was developed to assess VA across different pupil sizes by dynamically adjusting lighting conditions.

METHODS: A randomised, crossover, partially participant-masked clinical study was conducted with 53 habitual soft CL wearers (84 eyes; ages 20-40). Eyes were categorised into seven astigmatism groups (0.00 to -1.50 DC in 0.25 DC steps). Each eye was tested with three corrections: spherical soft CLs, custom toric soft CLs, and full-correction spectacles. VA was assessed using PUCS at five pupil diameters (2.5 mm, 4.0 mm, 5.5 mm, maximum, and minimum). The primary outcome was the between-correction difference in PUCS logMAR visual acuity, assessed at each pupil diameter. Secondary measures included conventional VA, subjective ratings, and lens preference.

RESULTS: PUCS VA decreased significantly with increasing pupil diameter across all corrections (p< 0.0001). Toric CLs provided significantly better PUCS VA than spherical CLs for astigmatism of -0.75 DC and greater, regardless of pupil diameter (p< 0.001). The mean toric-spherical difference was approximately 0.06 logMAR (≈3 letters) at -0.75 DC and 0.12 logMAR (≈6 letters) at -1.50 DC. Toric CL performance was comparable to spectacle correction across all cylinder groups. Participants favoured toric CLs over spherical lenses from -0.75 DC upwards, with no participants preferring spherical CLs at -1.25 DC or greater (p< 0.001). Toric CLs demonstrated excellent rotational stability.

CONCLUSIONS: The PUCS system provided robust evidence that toric CLs offer significant visual benefits at -0.75 DC or greater (within the tested range up to -1.50 DC), irrespective of pupil diameter. These findings support routine soft toric CL prescribing for astigmatism correction at or above this threshold to optimise visual performance and patient satisfaction.

CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov (Identifier: NCT04613882).

PMID:41579512 | DOI:10.1016/j.clae.2025.102604