Complications of Small Aperture Intracorneal Inlays: A Literature Review

Abstract

Presbyopia can be defined as the refractive state of the eye in which, due to a physiological decrease in the ability to accommodate, it is not possible to sustain vision without fatigue in a prolonged manner, along with difficulty focusing near vision. It is estimated that its prevalence in 2030 will be approximately 2.1 billion people. Corneal inlays are an alternative in the correction of presbyopia. They are implanted beneath a laser-assisted in situ keratomileusis (LASIK) flap or in a pocket in the center of the cornea of the non-dominant eye. The purpose of this review is to provide information about intraoperative and postoperative KAMRA inlay complications in the available scientific literature. A search was conducted on PubMed, Web of Science, and Scopus with the following search strategy: ("KAMRA inlay" OR "KAMRA" OR "corneal inlay pinhole" OR "pinhole effect intracorneal" OR "SAICI" OR "small aperture intracorneal inlay") AND ("complication" OR "explantation" OR "explanted" OR "retired"). The bibliography consulted shows that the insertion of a KAMRA inlay is an effective procedure that improves near vision with a slight decrease in distance vision. However, postoperative complications such as corneal fibrosis, epithelial iron deposits, and stromal haze are described.

Keywords: KAMRA inlay; SAICI; corneal inlay pinhole; intraoperative complications; postoperative complications; presbyopia; refractive surgery; small aperture intracorneal inlay.

Figure 1

Slit-lamp examination. Decentration of a KAMRA inlay toward nasal area. A temporary area of the cornea free of the KAMRA is observed, which allows light to pass through.

Figure 2

SD-AS-OCT of the anterior segment, revealing nasal decentration of the small-aperture corneal inlay. From left to right the nasal and temporal images are observed.

Figure 3

SD-AS-OCT of the anterior segment revealing a stromal hyperreflective signal. Caliper measurements from left to right (in µm): Total peripheral pachymetry (680), nasal KAMRA pocket depth (215), total central pachymetry (653), temporal KAMRA pocket depth (197).

Figure 4

Slit-lamp examination at 2 months after removal. Stromal leukoma-shaped 360 degree ring (stromal footprint) associated with the KAMRA and corneal epithelial iron deposits in a half-moon shape (similar to a Fleischer ring).