Factors Affecting Visual Acuity Outcomes in Corneal Inlay Patients
Narrative Responses:
Purpose
Evaluate the impact of femtosecond laser settings in the long-term visual outcomes of patients receiving a small-aperture corneal inlay.
Methods
Multi-center, prospective, non-randomized clinical study of 507 emmetropic presbyopes (pre-op spherical equivalent refraction: +0.50D to -0.75D). The inlay was implanted monocularly into a femtosecond created lamellar pocket. The laser spot/line separation varied from 4x4 to 9x9 um; attempted depth varied from 180-220 um. Spot/line separation, or equivalent, was used to group the femtosecond-pocket patients into sub-groups: 6x6 or less (N=153) and larger than 6x6 (N=249). Uncorrected distance, intermediate and near visual acuities from 36-month follow-up are presented.
Results
In the <6x6 group, 100%, 93% and 91% of patients achieved 20/40 or better uncorrected distance, intermediate or near vision. In the >6x6 group, 98%, 89% and 84% of patients achieved 20/40 or better uncorrected distance, intermediate or near vision. At 36 months, mean uncorrected distance (p=0.0005), intermediate (p=0.0002) and near (p=0.0363) visual acuities were significantly different between the <6x6 and >6x6 groups. Mean distance, intermediate and near visual acuities were approximately one line better with the tighter spot/line separation.
Conclusion
Tighter spot/line settings, creating a smoother interface, provided a significantly higher proportion of subjects achieving better uncorrected visual acuities 36 months after inlay implantation.