Transcleral or endoscopic cyclophotocoagulation support glaucoma therapy

Orlando, FL-Results from a retrospective review of outcomes after transscleral or endoscopic cyclophotocoagulation (TCP or ECP) for a variety of glaucoma conditions provide additional information on the efficacy and safety of these procedures, including in select subgroups composed of eyes with either neovascular glaucoma or better than count fingers vision. However, the data need to be interpreted carefully given the study's limitations, said Robert M. Beardsley, MD, at the annual meeting of the American Academy of Ophthalmology.

The analyses included 42 eyes that underwent ECP and 44 eyes treated by TCP at Jules Stein Eye Institute, UCLA School of Medicine, Los Angeles. In both treatment groups, patients were using an average of three glaucoma medications at baseline and had an average follow-up of 18 months.

However, the TCP group had more severe baseline disease than the ECP eyes with a higher mean IOP (45.3 versus 26.6 mm Hg) and worse vision (no light perception [NLP], 50% versus 2.4%). Twelve percent of ECP eyes underwent combined cyclophotocoagulation/cataract surgery versus none in the TCP group.

Compared with the ECP group, the TCP group had a significantly higher rate of progression to phthisis (20.5% versus 0%), said Dr. Beardsley, ophthalmology resident, who collaborated on the research with JoAnn Giaconi, MD, assistant clinical professor of ophthalmology, Jules Stein Eye Institute.

Subgroup analysis

Results of a subgroup analysis focusing on eyes with neovascular glaucoma (ECP, 7 eyes; TCP, 18 eyes) showed TCP also had a much greater IOP lowering effect than ECP in this setting (33 versus 3 mm Hg). However, ECP was better tolerated than TCP as there were no cases of progression to phthisis or hypotony after ECP compared with event rates of 39% and 11%, respectively, in the TCP group.

In another subgroup analysis of eyes with better than count fingers (CF) vision at baseline (ECP, 18 eyes; TCP, 7 eyes), TCP appeared safe, was more effective in lowering IOP, and was associated with less loss of vision and progression to NLP than ECP. Among ECP eyes, IOP was essentially unchanged, and almost 40% had a BCVA loss of more than 2 lines, including one eye that progressed to NLP vision, although that eye had repeated retinal detachments associated with Stickler's syndrome. In the TCP group, BCVA was stable, IOP decreased by about 50%, and no eyes progressed to NLP.

"This retrospective study was designed to evaluate and compare the IOP-lowering effects and complications of ECP and TCP, and the data confirm recent literature reports showing that ECP is generally safer than TCP, especially in eyes with neovascular glaucoma," Dr. Beardsley said. "However, while TCP is usually reserved for use in eyes with more advanced glaucoma, our subgroup analysis indicates it may be well-tolerated in eyes with better vision, which might support broadened use.

"However, our study has several limitations, the most important ones being related to its retrospective design, baseline differences in treatment groups, and small numbers in the subgroup analyses," he added. "Ideally, ECP and TCP would be compared in a prospective, randomized study."

ECP was done using an 810-nm laser endoscope (E2 Micro-Probe, Endo Optiks); 38 of the 42 cases were performed through a clear corneal incision and four were done through the pars plana in eyes that underwent combined vitrectomy. There were 13 eyes that had ECP combined with phacoemulsification or tube removal.

The TCP procedures were done using a proprietary 810-nm laser (OcuLight SL, Iridex) with a contact probe placed on the sclera (G-Probe, Iridex), and the treatment effect was titrated by adjusting both time and power.