Evaluation of the small-aperture intracorneal inlay: Three-year results from the cohort of the U.S. Food and Drug Administration clinical trial

Abstract

The small-aperture corneal inlay was found to be safe and effective, improving near vision both monocularly and binocularly with minimal effect on distance visual acuity.

Pinholes and presbyopia: solution or sideshow?

“…Laboratory studies demonstrate that, in near vision, binocular acuity closely follows that of the eye with the smaller pupil . Although, as expected theoretically, the inlay causes a small loss in visual sensitivity across the visual field, effects are minor . Kamra‐type corneal inlays are primarily intended for use with phakic patients but have also been used in patients with monofocal IOLs .…”

“…In general, as discussed earlier, small‐aperture optics would be expected to be less useful when light levels are low. Little quantitative work has been carried out on this aspect, although good levels of subjective satisfaction have been reported by patients with Kamra inlays for both day and night driving . If problems arise with small‐aperture corneal inlays, it is claimed that they are relatively easy to remove without any deleterious after–effects but explantation of small‐aperture IOLs is a more invasive procedure.…”

“…Typically, patients have ages 45–60 years, mean spherical errors between +0.50 and −0.75 D and cylindrical errors ≤0.75 D, and would normally have reading additions of +1.00 to +2.50 D. Residual accommodation may help to improve near performance of the younger phakic patients. Clinical reports show that the devices improve binocular near and intermediate vision to a level which is adequate for most tasks without compromising distance vision . Reading performance is improved and there is a high degree of spectacle independence for most tasks .…”

“…Surgical variants of small‐aperture corrections (a) the Kamra corneal inlay (b) the IC‐8 intraocular lens and (c) the Xtrafocus implant . The Kamra implant and the Extrafocus implant have zero refractive power.…”

“…Monocular through‐focus photopic visual acuities. Cases shown include: mean data for 114 subjects before and after implantation with the Kamra corneal inlay (Vukich et al ., 2018; Vilupuru et al ., 2015); and mean data for 12 subjects with the IC‐8 IOL (Grabner et al ., 2015). Defocus values have been adjusted so that best focus occurs at zero defocus for all subjects and patients.…”