Profocal Cornea: Mechanism and Clinical Performance of Transparent Intracorneal Inlay
Narrative Responses:
Purpose
To demonstrate with clinical data and ray-trace simulations the intermediate and near vision improvement with an intracorneal profocal inlay.
Methods
177 presbyopes implanted with a hydrogel intra-corneal inlay in their non-dominant eye (Raindrop Near Vision Inlay, ReVision Optics, Lake Forest, CA), at two OUS clinical sites. Major outcome measures were uncorrected ETDRS visual acuity for distance, intermediate and near, and task performance assessed with self-administered questionnaires. Using ray-trace (Zemax) in a finite eye model, we simulated letter charts to observe the dynamics of rays in order to understand the range of good near VA as a function of pupil size and spectacle defocus. The inlay induced anterior corneal surface change was derived from the postop – preop wavefront measurements.
Results
Mean preop UNVA (logMAR) was 0.51 and by 3 months improved to 0.06 (p<0.001). Similarly, UIVA improved 2.5 lines (0.38 preop to 0.12 at 3 months, p<0.001). Near task performance and near satisfaction improved after inlay implantation (p<0.001). Zemax simulations in bright light (3 mm pupil) predicted near acuity of 20/20 for at distances between 24 cm and 40 cm; in mesopic conditions (5 mm), a near acuity of 20/32 between 25 cm and 44 cm was obtained.
Conclusion
The Raindrop hydrogel intracorneal inlay creates a smooth steepening in the central cornea (“Profocal” cornea) that generates a gradient of power. This smooth elevation provides good near and intermediate visual acuity, good near task performance, and patient satisfaction.