It has been my experience that the later in life my patients get their spectacles, the more they dislike wearing them. The emmetropic presbyope is among the oldest patient population to need their first pair of spectacles. As our society has come to the realization that it is okay to have eye surgery to reduce spectacle dependence, many new and exciting technologies have surfaced for this patient subset. I believe that the PresView system (Refocus Group, Inc., Dallas) will have an excellent future position in presbyopia management.

PresView is designed to improve near vision ability, without impacting distance vision in phakic, natural, or postsurgical, emmetropic presbyopes. The system is composed of four PresView scleral implants, an automated sclerotome that creates tunnels for them to be placed into, and assorted surgical hand instruments. The implants—placed through a 75% depth sclera at the lens equator in the oblique quadrants—are designed to enlarge the diameter of the sclera around the lens, allowing for better near vision. No eye tissue is removed, and the self-fitting implants are designed to be stable in the eye.

EARLY PROCEDURES
The earliest surgeries with PresView took place in the 1990s, however, the implants tended to flip and/or subluxate from their tunnels. Results were good, until the implant moved. Since this time, numerous changes in implant design (ie, self-correcting for centering in the tunnel, and the requirement of a greater force to sublux) have ensured stability in the eye, culminating in the current self-centering implant.

Since the availability of the Visante OCT, (Carl Zeiss Meditec AG, Jena, Germany), we embarked upon a huge effort to scan patients who had the older implants to determine the optimal scleral implant position and design. We were able to correlate the change in the results of some patients to the subluxation of the implant. In these patients, the implants were initially repositioned and sutured in place, and an improvement in reading ability was restored. We have had the opportunity to replace the older implants that had subluxed with the new style; again, we restored results that the patient experienced prior to the subluxation.

With the new PresView implants, approximately 85% of patients read 20/40 or better Snellen near postoperatively. It is important to note that the PresView should only be used in phakic and emmetropic patients. Previous excimer vision correction is allowed. Some patients have improved seven lines of near visual acuity, and many are able to read 20/25. We are not affecting distance visual acuity, nor are we changing patients' axial length or distance refraction. We are analyzing our position data on optical coherence tomography to better determine placement and have improved the sclerotome design to get more reliable tunnel anatomy.

Currently, PresView is Conformiteé-Européenne (CE) marked, however, the US Federal Drug Administration (FDA) has not yet approved the device. An FDA Investigational Drug Exemptions phase 3 clinical trial for presbyopia that has enrolled approximately half of the 330-patient series, and a Canadian trial for glaucoma, are currently underway. Eight investigators are testing this device as part of the Investigational Drug Exemptions trial. The company is also expanding its European market, and during the Winter European Society of Cataract and Refractive Surgeons meeting in Athens, the company will train European surgeons on how to use the PresView.

At this time, we have noticed a slow learning curve associated with the PresView. During this time, the surgeon must devote adequate time to the surgery, instead of rushing through to get the implants in. The placement of the implants is of most importance, because they must be carefully positioned over the lens equator at 75% depth to achieve their optimal result.

The PresView is unlike most other vision correction surgeries, however, it has been compared with presby-LASIK or bifocal IOLs. One major difference is that the anatomy in all four tunnels must be perfect to have an effect on the space around the lens. Furthermore, the population for PresView surgeries are emmetropic to start—and 20/20. These may be difficult patients to treat with IOL technology, because (1) there are quality of vision issues with current bifocal implants, and (2) power determination is needed in patients who are postexcimer emmetropes. Although the phakic and emmetropic presbyope is historically hard to treat, the PresView implant is a great option for presbyopia correction in this population. I believe that this technology will be further used in the future, after US clinical trials are completed.

Barrie D. Soloway, MD, FACS, is Director of Vision Correction at the New York Eye and Ear Infirmary, and Assistant Professor of Ophthalmology at the New York Medical College. He states that he is a paid consultant to Refocus Group, Inc. Dr. Soloway may be reached at +1 212 758 3838; bsolowaymd@pol.net.