Abstract
Purpose:
To retrospectively investigate the effect of implantation depth in the cornea, with the Raindrop Near Vision Inlay*, on outcomes of presbyopic emmetropes at one year postoperative. *CAUTION: Investigational device. Limited by Federal (US) law to investigational use.
Methods:
373 presbyopic emmetropes were implanted with the Raindrop corneal inlay in the non-dominant eye beneath a femtosecond corneal flap as part of a prospective, multicenter, US clinical trial. The meniscus shape of the inlay is designed to improve near vision by changing the curvature of the anterior cornea to progressively increase refractive power from the pupil center. The implantation depth was calculated by dividing the corneal flap thickness targeted with the laser by the preoperative central corneal pachymetry. Trace corneal haze (grade 1) was measured by slit lamp examination, uncorrected visual acuities with Optec 6500, and wavefront topography also evaluated the optical effect of the inlay. Multivariate statistics determined the effect of implantation depth on these visual outcomes one year after Raindrop implantation.
Results:
The incidence of trace haze is strongly associated with implantation depth (p < 0.001), with significantly lower incidence for deeper implantations. The proportion of trace haze at least once during the first year was (i) 50% (5/10) of patients for the corneal depth from 22.0% to 24.9%, (ii) 23% (19/82) of patients at 25.0% to 27.9% depth, (iii) 11% (20/187) of patients at 28.0% to 30.9% depth, and (iv) 3% (2/61) of patients at 31.0% to 34.0% depth. Topography demonstrated a slightly weaker inlay effect for the deeper implantations, but patients still obtained a similar, significant improvement in near and intermediate acuities across all depths.
Conclusions:
Surgeons should target their femtosecond flap at 33% corneal thickness to optimize the visual outcomes with the Raindrop Near Vision Inlay. At this implantation depth, central corneal haze is minimized while still obtaining significant improvement in near and intermediate visual acuity for presbyopic emmetropes.