INTRACORNEAL INLAY

Outcomes data for presbyopia correction using a small aperture intracorneal inlay (KAMRA, AcuFocus) show excellent safety and efficacy that account for high rates of patient satisfaction and a low rate of removal. However, should any patient desire inlay explantation, the removal procedure is also very safe and results in rapid return to pre-inlay levels of near and corrected distance visual acuity, according to a retrospective analysis presented by Minoru Tomita MD, PhD, at the 2014 ARVO meeting in Orlando, US.

Dr Tomita conducted a review of 63 patients who underwent inlay removal. All patients had the device placed into a femtosecond laser-created pocket at one month after LASIK to correct ametropia. Mean time to removal was 11.3 ± 7.4 months, and all patients were followed to six months.

LogMAR UCDVA was 0.13 ± 0.26 pre-removal, decreased slightly at one week post-removal, but was 0.14 ± 0.26 at one month and stable thereafter. LogMAR UCNVA had returned to the pre-inlay level at one week and was unchanged through follow-up. Manifest refraction did not change significantly.

Mean BCDVA was significantly lower at one week and one month post-removal compared to the pre-inlay level, but had recovered by three months and remained stable. BCDVA was ≥20/25 in all eyes prior to placement of the inlay and in 97 per cent of eyes at six months; three eyes had a BCDVA loss of two lines at six months.

“More than 20,000 inlays have been implanted worldwide, and after moving from a flap-based procedure to inlay placement in a femtosecond laser-created lamellar pocket one month after thin-flap LASIK, the removal rate has decreased from six per cent to just 1.2 per cent,” said Dr Tomita.

“During consultation, patients interested in the inlay are informed of the benefits and risks. They are told that 95 per cent of our patients are satisfied and only a small proportion use glasses occasionally for reading. However, we also discuss the possibility of removal, including the potential reasons and outcomes. Based on our experience, patients are told that their vision is expected to recover to baseline, but that an enhancement procedure may be needed for optimal vision, and they are also counselled that other treatment options will remain available to address the presbyopia after inlay removal.”

TECHNIQUE

Dr Tomita said the inlay removal rate has decreased with use of the current inlay technique that is associated with more reliably predictable results, improved refractive stability, decreased recovery time and less dry eye. The primary reasons for inlay removal have been, in descending order, visual acuity, visual symptoms and adaptation failure.

“Some patients have concerns about night vision in the first months after surgery and are encouraged to wait because these symptoms usually resolve by six months. However, some patients still want to have the inlay removed immediately despite having excellent visual acuity,” Dr Tomita said.

Dr Tomita noted the inlay is easily visualised under the operating microscope because it is opaque, and the removal procedure is simple. “Removing the inlay is easier than the implantation procedure and definitely easier than implanting and removing a phakic or pseudophakic IOL,” he said.

Since the inlay adheres well to the stroma, which virtually eliminates the possibility for unwanted migration, it must first be released using a spatula. Then, it is grasped with the insertion forceps and pulled out of the pocket. Post-removal, patients are placed on a medication regimen similar to that used post-LASIK.

Dr Tomita also reinforced that, as with all surgical procedures, appropriate patient selection is a critical factor underlying success with the small aperture inlay. He suggested the AcuTarget HD is a useful screening aid for evaluating the optical quality of the eye and identifying early lens changes and ocular surface issues that can compromise short- and longer-term outcomes.

The Kamra implant is available in Europe and Asia.

Minoru Tomita:
tomita@eyecanmedical.com