Optimal keratoplasty (Opti-K, NTK Enterprises), a novel non-invasive laser keratoplasty procedure, is a safe and promising treatment for presbyopia in emmetropes and low hyperopes, reported Sherry L. Audycki, OD, recently.
Performed using a proprietary continuous-wave thulium fiber laser with a sapphire applanation window, the procedure reshapes the cornea and creates a multifocal effect to provide clear distance and near vision, without causing any epithelial disruption and its associated risks and morbidity.
The treatment benefit is not permanent, but its safety and tolerability allow the treatment to be repeated. The retreatments are effective and can be titrated over time to allow for any natural refractive shift, Dr. Audycki said.
Dr. Audycki is a clinical optometrist with Advanced Eye Centers, in Dartmouth, MA, one of two sites participating in a U.S. IDE clinical trial monitored by the FDA. Harry Glen, MD, is the principal investigator at Advanced Eye Centers and treated nine patients. James J. Salz, MD, Los Angeles, is the other principal investigator and treated one patient.
"Optimal keratoplasty is a simple, fast, comfortable, low power laser treatment that is meant to be repeatable. Per protocol, the patients enrolled in our study were treated only in their dominant eye. Now they are excited to have a repeat treatment and treatment in their fellow eye," she said.
Patients participating in the U.S. IDE study were presbyopes with mild hyperopia (SE +1.00 D to +2.00 D). They were scheduled to return for monthly visits; five eyes received a planned secondary treatment to date.
Twelve-month post-primary treatment data showed mean distance uncorrected visual acuity (UCVA) was 20/28.9, representing a mean gain of 2.9 lines from baseline; distance UCVA for these eyes should be further improved following planned secondary treatments. Binocularly, these patients had mean distance UCVA of 20/22.5, even though their fellow eyes have yet to be treated.
Twelve-month post-secondary treatment data are only available for two eyes due to one patient dropout and two patients with large control eye refractive changes (presumably due to progressive hyperopic shift). For those two eyes, mean UCVA was 20/29.0 monocularly and 20/23.8 binocularly.
The patients are undergoing comprehensive evaluations to document the safety of the procedure. So far, there have been no adverse effects; at 18 months, corrected distance BCVA was 20/20 or better in all eyes. Astigmatism increased > 0.5 D in two patients, which appeared to be a temporary change and resolved to pre-treatment levels.
Tear osmolarity was unchanged. Endothelial cell density decreased slightly, but the change was not different from that recorded in the control eyes. Patients had no subjective complaints of pain, discomfort, dryness, or halos while driving at night.
A pilot study of the procedure enrolling emmetropic presbyopes was performed in the Bahamas, where K. Jonathan Rodgers, FRCS(C), DABO, was principal investigator. The procedure is now being offered to patients in the Bahamas outside of the study protocol. It also received the CE mark in Europe and is being performed in Bermuda, Italy, and Switzerland.
"Good results are being achieved in patients treated outside of the United States, and hopefully will provide us with more data to understand the variability in the duration of the treatment effect and allow us to perhaps identify predictive factors that can be used for patient counseling," Dr. Audycki said.
Histological studies in animal eyes show the treatment does not destroy the cornea or cause collagen shrinkage. Rather, it is thought that a change in corneal hydration underlies its clinical effect and that regression occurs over time as a result of rehydration.
Sherry L. Audycki, OD
Dr. Audycki has no financial interest in the subject.