Treatment of Presbyopia in Emmetropes Using a Shape-Changing Corneal Inlay

Contrast Sensitivity in Emmetropic Presbyopes with Small-Aperture Inlay Implantation: Normative Values and Postoperative Outcomes

“…Additionally, the postoperative CS was maintained within normative range established from preoperative means in all CS conditions throughout 36 months. These results were generally comparable to a report on another presbyopia-correcting intra-corneal device [19]. Whitman et al reported that there was some CS loss in the Raindrop Near Vision Inlay ("Raindrop") eye at high spatial frequencies (-0.19 logCS at 12 cpd and -0.23 logCS at 18 cpd) in monocular photopic condition and a smaller loss at high spatial frequencies in monocular mesopic condition.…”

“…We demonstrated that the mild reductions in monocular CS in KAMRA inlay eyes were within the normative ranges and were comparable to those from other presbyopia-correcting procedures such as shape-changing corneal inlay [19]. Binocular CS in KAMRA inlay subjects were well maintained after surgery and CS has been stable through three years postoperatively.…”

“…Whitman et al reported that there was some CS loss in the Raindrop Near Vision Inlay ("Raindrop") eye at high spatial frequencies (-0.19 logCS at 12 cpd and -0.23 logCS at 18 cpd) in monocular photopic condition and a smaller loss at high spatial frequencies in monocular mesopic condition. That study [19] also measured CS using Optec 6500 Vision Tester but did not specify how they scored subjects who could not see any patches to account for the floor effect. The postoperative CS loss in KAMRA inlay eyes was smaller compared to Raindrop eyes in the photopic condition, and was a little bigger in mesopic conditions.…”

“…The postoperative CS loss in KAMRA inlay eyes was smaller compared to Raindrop eyes in the photopic condition, and was a little bigger in mesopic conditions. This reversed impact from lighting condition can be explained by the different mechanisms of action of these two inlays: KAMRA inlay is a 3.8 mm opaque annular ring with a 1.6 mm central aperture and provides extended depth of focus from near through far by restricting unfocused light from reaching the retina; Raindrop Near Vision Inlay is a 2 mm meniscus-shaped inlay whose volume biomechanically raises anterior corneal surface over the inlay and it creates a profocal power profile to provide near vision in the most steeply curved central area, intermediate vision around the central area, and distance vision in the periphery beyond approximately a 3-mm diameter [19]. Theoretically, KAMRA inlay eyes may experience only a very mild impact on distance vision and photopic distance CS due to diffraction from the 1.6 mm central aperture, similar to the report of constricted pupils mildly reducing CS [20], and the reduced illumination on the retina in KAMRA inlay eyes may additively exemplify its impact on CS under low light.…”

“…As shown in simulations, this hydrogel inlay creates a pupil-dependent trade-in image quality in exchange for enhanced depth of focus [23] similar to what has been found with center near multifocal contact lenses [24] thus affects distance vision and photopic distance CS. With this optical design, however, the negative impact on CS may be less evident under mesopic conditions where the pupil enlarges, because distance vision is viewed through the periphery of the cornea, that is, the area of available peripheral distance zone increases with larger pupils and as a result reduces the loss of mesopic distance CS [19].…”