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From Beyoglu Eye Research and Training Hospital, Istanbul, Turkey (AA, AD, HUÇ, KIÇ, NBÇ, DY, IY); Private Practice, Istanbul, Turkey (ÖFY); and AcuFocus, Inc., Irvine, California (CVDP).
Dr. OFYilmaz is a consultant for and Dr. van de Pol is an employee of AcuFocus, Inc. The remaining authors have no financial or proprietary interest in the materials presented herein.
Current surgical approaches for presbyopia involve lens-based (most frequently intraocular lenses implanted after cataract extraction) and corneal-based procedures in phakic eyes.1-6 The AcuFocus ACI-7000 intracorneal inlay (AcuFocus, Inc., Irvine, CA), later named the KAMRA corneal inlay, increases the depth of field through the principle of small-aperture optics with the goal of improving intermediate and near vision without markedly affecting distance vision.7 The first efficacy and safety data were published by Yilmaz et al. in 2008.7 However, it is not known if implantation of the KAMRA corneal inlay changes biomechanical properties of the cornea and its effects on intraocular pressure (IOP) measurements are not studied well in the literature. Therefore, it is important to understand the effects of KAMRA corneal inlay implantation on these parameters to monitor IOP after surgery.
The Ocular Response Analyzer (ORA) (Reichert, Inc., Buffalo, NY) is designed to obtain in vivo measurements of corneal biomechanical properties and IOP.8 Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated IOP (IOP<subscript>g</subscript>), and corneal-compensated IOP (IOP<subscript>cc</subscript>) are metrics used in this device to describe biomechanical properties of the cornea and IOP.
The purpose of this study was to compare CH, CRF, IOP<subscript>g</subscript>, IOP<subscript>cc</subscript>, and IOP measurements obtained by Goldmann applanation tonometry in eyes implanted with the KAMRA corneal inlay versus non-implanted fellow eyes, and study changes in these parameters during the follow-up period in implanted eyes.
<bold>Patients and Methods</bold>
This retrospective study was performed at the Beyoglu Eye Training and Research Hospital in Istanbul, Turkey. The hospital's ethics committee approved the study. Medical records of patients who underwent small aperture corneal inlay implantation at our clinic were reviewed retrospectively. Patients with emmetropia who had the implant in a stromal pocket and preoperative and postoperative CH, CRF, IOP<subscript>cc</subscript>, and IOP<subscript>g</subscript> measurements using the ORA were included in the study. Patients who had any accompanying ocular disease or previous history of any other surgical intervention were excluded. There were...