Scleral implants improve presbyopic near vision

Niagara Falls, NY-Implantation of presbyopia scleral implants (PresView, Refocus Group) using a scleral spacing procedure with limbal-relaxing incisions is providing marked improvements in near vision in patients with presbyopia.

Michael J. Endl, MD, talked about the results achieved with implantation of this technology and a hypothetical theory about how the procedure works to increase.

 “The scleral-spacing procedure is beneficial over other surgical options for presbyopia in that it provides a full range of focus and it is reversible. It is an extraocular procedure sparing the visual axis, and the cornea remains untouched,” said Dr. Endl, in private practice in Niagara Falls, NY.

The implants are positioned 4 mm posterior to the limbus in the four quadrants between the extraocular muscles.

“They are less invasive in that they are not implanted inside the eye and they are an alternative to IOLs. The implants are not associated with serious adverse events, such as endophthalmitis or retinal detachment, or development of halos and glare that are associated with contrast sensitivity changes with IOLs,” he explained.

Initially, the procedure required a full conjunctival peritomy, which was associated with an extended healing time. In the current procedure, creation of small pockets, into which the implants are positioned, spares the inferior and superior conjunctiva. In the United States, the spaces are closed with 8-0 Vicryl sutures; in Europe, surgeons are using tissue glues that are not yet available in the United States, according to Dr. Endl.

A recent improvement in the procedure has the implants shaped like a dog bone. The original implants were oblong with a half arc at the end, which did not hold the implants in the preplaced scleral loop. The implant can now be locked in place to prevent it from slipping. Dr. Endl reported that no implants have slid out of place in the 18 months of the FDA study.

The procedure is associated with little patient discomfort. Subconjunctival hemorrhages and slight irritation are possible for the first 7 to 10 postoperative days.

The study was designed to evaluate the improvement in near acuity with the presbyopia implants and the scleral-sparing procedure using a limbal-sparing approach. The patients ranged in age from 50 to 60 years with a best-corrected distance visual acuity of 20/20 or better. The preoperative near vision ranged from 20/50 to 20/100. All patients were close to plano with an upper level of astigmatism of 1 D.

“All patients who have been followed for 18 months had either more than two lines of visual improvement in near vision from baseline or 20/40. The average improvement was 2.92 lines of vision; 45% of patients achieved four lines of improvement (average, 20/40 to 20/32),” Dr. Endl said.

The average at 12 months was an improvement in the average preoperative vision of 20/63 to almost 20/30, which represents about three lines of improvement in the near vision.

“It is important to note that we don’t know exactly why this procedure works to improve accommodation, but we are seeing improvements in the near vision. The thought is that by increasing the circumlental space between the ciliary body and the lens, which narrows with aging, we can tighten the underlying ciliary body and allow it to work and extend the youthful accommodation a bit longer,” Dr. Endl said.

The importance of this study, he pointed out, is that what is happening in the eye is being measured. Refocus Group is conducting studies to determine when patients see the difference when moving from distance to near vision and to determine the mechanism of the visual improvement.

Dr. Endl has no financial interest in any product mentioned in this article. The inlays, which have a CE mark in Europe, are currently in phase III trials in the United States.

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