Transscleral cyclophotocoagulation may lower IOP after tube shunt failure

J Glaucoma. 2012;21(2):83-88.

Transscleral cyclophotocoagulation significantly reduced IOP but did not improve mean visual acuity after previous tube shunt failure, according to a study.

Perspective from Steven J. Gedde, MD
OSN Glaucoma Board Member

"[Transscleral cyclophotocoagulation] has a significant ocular hypotensive effect on glaucoma refractory to both tube shunt and medical therapy. The safety of this intervention remains unclear in this high risk patient population and warrants further study," the study authors said.

The retrospective study included 32 eyes of 31 patients with uncontrolled glaucoma. Median patient age was 66.3 years. Each eye had previously undergone implantation of an aqueous tube shunt and was undergoing the maximally tolerated medication.

The mean interval between tube shunt implantation and transscleral cyclophotocoagulation was 2.7 years.

Eyes underwent transscleral cyclophotocoagulation with an Iridex diode laser with a maximum 360° of treatment. Mean follow-up was 17.1 months. Final analysis included 30 eyes.

Study results showed that mean IOP diminished from 28.6 mm Hg to 16.8 mm Hg at 3 months and 14.7 mm Hg at 1 year. Both reductions were statistically significant (P < .0001).

Mean number of IOP medications was reduced from 2.7 to 1.7 at 3 months and 1.8 at 1 year.

Mean logMAR best corrected visual acuity diminished 0.19 at 3 months; the change was significant (P = .022).

Complications included hypotony in four patients, hyphema in two patients, failed corneal transplant in one patient and loss of light perception in five patients.

Further study with a longer follow-up interval is warranted, the authors said.

Perspective

Steven J. Gedde, MD<br>OSN Glaucoma Board Member

The popularity of tube shunts is growing. Medicare data demonstrate that these devices are being increasingly utilized in the surgical treatment of glaucoma. However, the management of patients who have failed tube shunt surgery is complex and generally involves placement of a second tube shunt or cyclodestruction.

Ness and colleagues have published the largest case series to date on the use of transscleral cyclophotocoagulation (TSCPC) after tube shunt failure. Diode TSCPC produced significant intraocular pressure reduction in eyes with glaucoma refractory to both tube shunt implantation and adjunctive medical therapy, although 22% of patients required more than one treatment to achieve a pressure response.

It is desirable to err on the side of initial undertreatment with TSCPC to avoid ocular hypotony, but this means that repeat treatment is not unexpected. It is concerning that a decrease of two or more lines of best-corrected visual acuity occurred in 56% of patients at last follow-up, but this high rate of vision loss may be related to the refractory population that was treated in this study.

The authors are to be congratulated for providing valuable information that describes the outcomes of TSCPC in patients who failed tube shunt surgery.

Steven J. Gedde, MD<br>OSN Glaucoma Board Member

Disclosures: Dr. Gedde has no relevant financial disclosures.