Femtosecond Laser Liquid Optics Interface as Low Vision Optical Resource

To assess the efficacy of a low-cost optical magnifier created from the repurposed femtosecond laser interface used in cataract surgery to reduce healthcare waste and financial burden for low-vision patients.

This prospective study included 16 Brazilian patients from the Low Vision Department of the Irmandade da Santa Casa de Misericórdia de São Paulo. Participants had visual acuity between +0.5 and +1.3 logMAR and visual field constrictions under 20°. The Catalys^® femtosecond laser interface lens, usually discarded after surgery, was sterilized and attached to a recyclable support to create a magnifying device. Patients were trained to use it for 30 days. Visual function was assessed with the NEI VFQ-25, and reading performance was measured using the MNREAD-P test.

Thirteen patients (81.25%) completed the study. The use of the optical device led to significant improvements in all MNREAD-P parameters. Reading acuity improved from 0.74 ± 0.19 logMAR (20/110 Snellen) to 0.41 ± 0.22 logMAR (20/50 Snellen) (p < 0.001). Critical print size decreased from 0.85 ± 0.19 logMAR (20/140 Snellen) to 0.56 ± 0.24 logMAR (20/70 Snellen) (p < 0.001). Maximum reading speed increased from 41.4 ± 18.0 words per minute (wpm) to 56.2 ± 25.2 wpm (p < 0.001). NEI VFQ-25 scores improved from 32.7 ± 13.8 to 46.9 ± 15.0 (p < 0.001), with increases observed in all subcategories, particularly in "Reactions to Vision Problems."

Repurposing the femtosecond laser interface lens as a low-cost magnifier showed promising improvements in reading and visual function for low-vision patients while addressing healthcare waste. Further studies with larger samples are recommended to validate and expand this sustainable approach in visual rehabilitation.