XXXI Congress of the European Society of Cataract and Refractive Surgeons: Scleral implants reduce IOP

Nov 01, 2013

Preliminary results suggest that the PresVIEW ScleraI Implant, a two-part clear plastic locking implant designed to provide secure placement in the eye, is safe and effective for presbyopic emmetropes and has demonstrated interesting intraocular pressure (IOP) reduction capabailities.

Preliminary results suggest that the PresVIEW ScleraI Implant (Refocus Group; Dallas, Texas, USA), a two-part clear plastic locking implant designed to provide secure placement in the eye, is safe and effective for presbyopic emmetropes and has demonstrated interesting intraocular pressure (IOP) reduction capabailities. These findings were announced by Dr James Katz (Midwest Center for Sight; Des Plaines, Illinois, USA) during the 'New evaluation tools in refractive surgery' session, which was held on the second morning of this year's ESCRS meeting.

Study details

Dr Katz discussed the details of the controlled, multicentre, 2-year investigational device exemption (IDE) clinical trial, which is taking place across 14 sites in the USA. "The idea of this study is to evaluate the effect that bilateral implantation of the scleral implant has on distance corrected near visual acuity (DCNVA)," he explained. The minimally invasive procedure involves the placement of PresVIEW ScleraI Implants in the primary eye, circumferentially in oblique quadrants of the sclera just posterior to the calculated lens equator; the fellow eye is implanted ≥15 days after the placement in the primary eye.

Very interesting findings

Patients already involved in the study were followed for up to 24 months after placement of the scleraI Implant. Dr Katz revealed that there was an improvement over time of visual acuity that led to an improvement of 20/40 (DCNVA) or better bilaterally at the final follow up of 24 months. "So, a large improvement," he confirmed. "We really demonstrated the improvement over time from 6 months to 2 years and we continue to see improvement."

This was also similarly found using the ETDLS charts, where Dr Katz noted that there was on average an improvement from baseline of around 40 letters to nearly 60 letters at 24 months.

"What's interesting, however, is that we found a mean change of IOP from baseline," he asserted. "So, we looked at the IOP of all the patients, including 645 eyes, and saw pressures randing from 6 mmHg all the way to 23 mmHg at baseline." At 6 months the mean IOP was 13.4 mmHg (–8.5%, n = 595; range: 6–22 mmHg, at 12 months it was 12.9 mmHg (–11.8%, n = 325; range: 6–21 mmHg), at 18 months it was 12.6 mmHg (–14.3%, n = 213; range: 6–19 mmHg) and at 24 months it was 12.5 mmHg (–14.9%, n = 132; range: 6–20 mmHg).

"We also had a cohort of patients with IOP of 18 to 23 mmHg and when we looked at baseline and tracked it out through the follow up period, we noted an almost 30% reduction in IOP over this period of time," Dr Katz emphasized. The mean IOP for this group was 15.2 mmHg (–19.1%, n = 107; range: 8–21 mmHg) at 6 months, 14.2 mmHg (–24.6%, n = 56; range: 8–20 mmHg) at 12 months, 13.9 mmHg (–6.3%, n = 34; range: 8–19 mmHg) at 18 months and 13.4 mmHg (–29.0%, n = 24; range: 8–18 mmHg) at 24 months.

"This was a very interesting finding for us. The study was not designed to control or demonstrate a reduction in IOP, it was not one of the primary endpoints," he asserted. "So, a new study was designed to show a reduction in IOP among patients with ocular hypertension (OHT) or primary open-angle glaucoma (POAG)."

What are the next steps?

The specifically designed clinical trial is now underway in the UK to obtain data related to the implantation of PresVIEW ScleraI Implants in patients with OHT and POAG who are managing their disease with 1–3 medications. As well as evaluating whether it can reduce IOP in the treatment of glaucoma and OHT, the trials are designed to determine if implantation of the PresVIEW ScleraI Implant device in the eye via the Refocus Procedure will reduce or eliminate the need for reading glasses that arises from presbyopia.

"In conclusion, this procedure shows promise as a potential surgical solution for age-related presbyopia and near emmetropia patients without affecting distance VA. Near vision improvement is maintained and improved throughout the 2 years of this study," concluded Dr Katz.

Dr Katz has indicated that there has been significant investment interest, travel and research have been funded, fully or partially, and consultancy fees are received.

x