New implants may give presbyopes another option

In limited studies, RestorVision Reading Implants have been shown to correct presbyopia in both eyes, although only one eye has the implant.

AURORA, Colo. — The RestorVision Reading implant is showing signs of being an effective surgical treatment for presbyopia in early clinical studies.

The RestorVision Reading Implant clinical study has been under way for several years. The implants were invented by Howard N. Straub, DO, in private practice here.

The reading implants are small and “dolphin shaped.” The design apparently requires implantation in only one eye to generate an effect in both, according to Dr. Straub.

A powerful treatment

“Since the days of Fyodorov, we’ve known that if you alter the sclera there’s a change to the vision. The only thing we really understand is that it works, but not really how it works,” Dr. Straub said.

His surgical technique uses two to four reading implants placed in only one of the patient’s eyes, within scleral tunnels, made tangentially to the corneal limbus at specific areas, in the region of the pars plana at a depth of 350 µm to 400 µm.

The difference in this implant vs. others is the design Dr. Straub said. This implant uses a smooth arch with a tapered back, and also features a textured underside to keep the implant from backing out. It is made of PMMA and is computer-generated and tumble-polished.

“The eye doesn’t even know they’re there. This keeps the body from rejecting it, encapsulating it or trying to absorb it. It basically forces the eye to ignore it,” Dr. Straub said.

The implants are smaller than a grain of rice. They feature a dolphin tail, which keeps the implant from pulling through and from turning over. It has the added benefit of keeping the implants on the outside of the sclera in the unlikely event they enter the globe during surgery.

“We get good correction with this design and material. We’re not quite sure where we’re getting these forces, but we’re working to find out. We think it may be using the Helmholtz theory. Or we may be using science that has not been presented yet. We’ve been working on this for several years. We’ve worked closely with the Food and Drug Administration, and we’re confident with the performance of the product,” Dr. Straub said.

Dr. Straub has applied for an Investigational Device Exemption to begin clinical trials in the United States. He said he also expects to receive the CE Mark from the European Union this summer.

RestorVision data

Reading Implants have been inserted in the dominant eye, nondominant eye and in both eyes. When the surgery is performed on one eye, reading vision improves in both eyes, Dr. Straub said. Every patient to date has been able to read at least 20/25, without correction, immediately after surgery.

When four implants were placed in both eyes, some patients had mild convergence difficulties, which was believed to be from too much power produced by the implant. Removability and reversibility have been demonstrated on two patients who are still being followed in the international study.

In January, the technique was changed to implanting only two implants superiorly in one eye. Patients continued to read immediately after the surgery in each eye without correction.

The two-implant technique in one eye is particularly inviting because there is less chance of compression of the anterior segment vasculature, Dr. Straub said.

The surgical procedure time, which was running approximately 45 minutes to an hour for four implants, is now significantly less, he said.

There is much less conjunctival injection and subconjunctival hemorrhage postoperatively, since most of it is under the upper eyelid and not as noticeable cosmetically. There also appears to be less postop lid edema, according to Dr. Straub.

If reading implants extrude, the extrusion has been observed to be outward and not inward into the globe. Extrusion of the implant is usually due to placing the implants too superficially or not having adequate coverage by both conjunctiva and Tenon’s capsule.

To date, 152 Reading Implants have been implanted in 39 eyes of 33 patients. Eighteen patients have been followed more than 2 years and are continuing to read well. The range in ages has been from 44 years to 64 years. Dr. Straub said with increasing age there appears to be no significant lessening of effect.

There have been no distance visual acuity losses as a result of the Reading Implants, and all patients to date read immediately following the procedure.

So far the complication rate has been low, Dr. Straub said. Complications in the four-implant study include three eyes of 39 eyes, which had two of the four implants extrude. Two patients remain with 20/25 or better uncorrected near in each eye. The third patient had the other two implants removed because their superficial placement led to conjunctival irritation. Another patient had the implants removed early in the study due to their superficial placement.

After removal of implants, the patients lost reading correction gradually over a 6-month period and returned uneventfully to wearing near vision correction. Four patients had mildly increased IOPs (highest pressure 30 mm Hg). Dr. Straub attributed this to steroid response from the use of 1% prednisolone acetate postop.

In the international study so far, 46% of the patients are over 2 years postop. Distance visual acuity remains stable. Near visual acuity remains improved.

Future of the RestorVision implant

Of the studies, Dr. Straub said, “I’m so into the project right now. This has been entrepreneurial. There are no major corporations behind us. Just like the good old days, just a lot of ophthalmologists working together on a project.”

With almost 50% of patients reading perfectly as far as 3 years out, Dr. Straub said he is more concerned that the implants work first. While he and the other investigators are exploring why the uncorrected eye reads better than the corrected eye or why the corrected eye reads at all, they have seen that the RestorVision implants get better acuities at 7 inches vs. other implants that use a 40-inch test to monitor reading.

“Our patients can read at comfortable distances. We’ve focused on getting the job done; we’ll work on theory next,” he said.

“Our protocol was to do surgeries only on the dominant eye with four implants per eye. We realized, after a late postop extrusion involving one of the surgeries, that just two implants could be used to make a difference,” he added.

In January, Dr. Straub’s international investigators began researching the use of two implants only.

“However, what we’re going to do with the FDA is continue to work with four implants. The two-implant system seems a little safer for protecting the anterior segment from an accident. However, for this study it’s important to use four implants as a baseline,” he said.

Reading Implants are small and “dolphin shaped.” The design requires implantation in only one eye to generate an effect in both. They are made of PMMA and are computer-generated and tumble-polished.	Two to four Reading Implants are placed in only one of the patient’s eyes, within scleral tunnels, made tangentially to the corneal limbus at specific areas, in the region of the pars plana at a depth of 350 µm to 400 µm.
Patient at 1 month postop.	Patient at 1 year postop.
Patient at 3 months postop.	Patient at 10 months postop. Distance visual acuity remains stable. Near visual acuity remains improved.

Same patient at 10 months postop. Patient can read well.

For Your Information:

• Howard N. Straub, DO, can be reached at 750 Potomac Street, Suite 223, Aurora, CO 80011; (303) 344-0295; fax: (303) 344-0307; e-mail: HStraub628@aol.com. Dr. Straub has a direct financial interest in the RestorVision Reading Implants.