Refinements made to the scleral spacing procedure that uses a scleral implant and a limbal-sparing incision have improved the long-term efficacy of the procedure.
All patients treated with this new technique internationally had greater than 3 lines of improvement in the near vision, with the vision improving up to 7 lines in some patients, said Michael J. Endl, MD, who is in private practice in Niagara Falls, NY. Dr Endl discussed the results of this study on behalf of Barrie D. Soloway, MD, New York Eye and Ear Infirmary, New York.
"Presbyopia can be addressed by static corrections of the cornea, by multifocal ablations or implantation of multifocal IOLs, or by dynamic corrections involving implantation of an accommodating IOL (Crystalens, Bausch + Lomb) or by SSP, which changes the architecture of the sclera over the ciliary body to attempt to improve the focusing power of the lens," Dr. Endl said.
The original SSP technology was slightly flawed in that the oblong implant design allowed the implant to shift postoperatively out of the scleral belt loops. The design was refined to improve the stability of the implant by including a locking mechanism that resembles a dog bone at the end of the implant and that keeps it from slipping out of the scleral belt loop, Dr. Endl explained.
Patients who have undergone SSP with the original implants had achieved from 1 to 3 D of improved near focusing, but this diminished in those patients that had implant slippage. The cohort of patients who received the new scleral implant show better near focus ability with time and no evidence of slippage.
Another refinement involves the marking technique, which has been improved and is now much easier and reproducible through the use of a barrel that allows placing of reproducible scleral marks 4.25 mm from the limbus.
In addition, the blade guard was shaved out of the way, which allows the sclera and the positioning marks to be better visualized when placing the instrument prior to performing the scleral tunneling step. Additional improvements in the grips on the underside of the footplate allows it to envelop more to the bottom and are flatter against the surface of the eye.
"This allows the surgeon better visibility, a better grip on the sclera, and more reproducibility," Dr. Endl said.
In the limbal-sparing conjunctival approach, incisions are made for 70° centered at the 3 o'clock and the 9 o'clock positions and no longer include the 360° full peritomy.
"This is a big improvement for glaucoma surgeons because it spares the conjunctival tissue superiorly and interiorly," he said.