Diode laser cyclophotocoagulation: dose-standardized therapy in end-stage glaucoma.

BACKGROUND

Ciliary body ablation in end-stage glaucoma has been widely performed with cryotherapy and neodymium:yttrium aluminium garnet (Nd:YAG) laser, both techniques frequently involving considerable pain and postoperative inflammation, with an unpredictable final intraocular pressure (IOP) and a significant risk of phthisis. Diode laser cyclophotocoagulation (cyclodiode laser) has recently been introduced in an attempt to avoid some of these problems.

METHODS

Thirty patients with uncontrolled IOP and advanced glaucoma were divided on clinical grounds into two groups and were treated with either a half or a full standardized dose of laser (40 x 1500 mW for 1500 ms) and monitored for IOP control, visual acuity, postoperative inflammation and phthisis. Success of IOP control was defined as IOP < 22 mmHg or a decrease in IOP of > 30%; preservation of visual acuity or control of pain in blind eyes was also assessed.

RESULTS

A sustained lowering of IOP was achieved in 90% of patients, with a mean follow up of 10.4 months. For the full treatment cases (group A), mean (+/-SD) pre-operative and postoperative IOP was 49.4 +/- 11.2 and 25.8 +/- 17.7 mmHg, respectively (a 48% reduction); 55% of patients achieved IOP < 22 mmHg and 68% gained an IOP reduction of > 30%. For the half-treatment cases (group B). the mean pre-operative and postoperative IOP was 29.4 +/- 4.3 and 18.9 +/- 5.7 mmHg, respectively (a 36% reduction); 63% of patients achieved IOP < 22 mmHg and 50% gained an IOP reduction of > 30%. Neovascular glaucoma was present in 60% of patients; the full-treatment subgroup of these patients achieved a mean lowering of IOP of 58%. Of 22 sighted eyes, 11 (50%) recorded no change in vision; seven (32%) eyes lost and four (18%) eyes gained vision; pain control was achieved in six of eight blind eyes (75%). There was no significant postoperative inflammation, one case of hypotony and no suggestion to date of sympathetic ophthalmia.

CONCLUSION

Diode laser cyclophotocoagulation appears to be simple, safe and is frequently successful in the control of IOP in end-stage glaucoma. Optimum dosage parameters remain to be determined.