IFS CATARACT INCISIONS

The femtosecond laser can be used to create precise clear corneal incisions for cataract surgery using a proprietary software algorithm, Shamik Bafna MD, of the Cleveland Eye Clinic, Ohio, US, told the 2013 American Society of Cataract and Refractive Surgery annual symposium. In a prospective trial, the device cut true tri-planar main and paracentesis incisions that measured on average less than 0.1mm of intended size, and were watertight immediately after surgery and the next day. The IRB-approved study involved 37 patients at two centres who received tri-planar main and single-plane paracentesis incisions cut with an iFS femtosecond laser (Abbott Medical Optics). The device was approved last year for arcuate incisions for astigmatism treatment with cataract surgery, and some surgeons have used it off-label for cataract entry incisions, Dr Bafna noted. This trial was a test of an AMO incision programme for accuracy and wound sealing.

All patients underwent cataract removal and intraocular lens placement surgery the same day incisions were made. Some 19 patients received incisions and surgery in the same centre, while another 18 had incisions cut at one centre and were transported to another about three kilometres away for surgery. Between incisions and surgery, patients were examined at the slit lamp and by OCT. Seidel tests for aqueous leakage were performed immediately after incisions and one day after cataract surgery, Dr Bafna said. In all cases, both clear corneal entry and paracentesis incisions were observed at the slit lamp immediately after cataract surgery, Dr Bafna reported. All eyes were negative for aqueous leakage after incisions and the next day. 100 per cent of incisions were intact. Cataract removal and IOL placement were successful in all cases, and no adverse events were observed.

In terms of accuracy, the results were excellent. For clear corneal incisions, the average programmed anterior width was 2.74mm and the average achieved 2.75mm, a difference of just 0.01mm. Posterior CCI widths were nearly as good, with an average difference of just 0.04mm. Anterior paracentesis widths differed an average of 0.10mm while posterior width differences averaged 0.01mm. “Pretty much what you programmed was what you got,” Dr Bafna said. OCT images confirmed that tri-planar main incisions were achieved in all cases, Dr Bafna said. “You can clearly define how the incisions go down vertically, and then horizontally in three planes.”

No complications

OCT and Seidel tests after incisions took time, so the average lag between incision creation and surgery was 91 minutes overall, Dr Bafna noted. However, the time for patients treated at the centre that required transport between the incision and surgery were on average 29 minutes longer than the 77 minutes averaged at the facility with both laser and surgery suite in-house. No incidents of complications were noted with transport, though AMO recommends placement of an eye shield, which was done for this study, Dr Bafna said. “The main thing we did notice was the importance of marking the patient’s eyes prior to performing incision creation in order to locate the exact location of the incisions.”