Molteno tube implantation for neovascular glaucoma. Long-term results and factors influencing the outcome

Abstract

Background: The Molteno implant has been shown to be useful in the treatment of neovascular glaucoma. However, a wide range of success rates has been reported. This is related to the use of differing criteria for success, varying periods of follow-up, and difficulty in quantifying the preoperative condition of the eye.

Methods: The authors studied the long-term results of the Molteno single-plate implant in 60 eyes with neovascular glaucoma using Kaplan-Meier life-table analysis. Age, visual acuity, underlying retinal diseases, and preoperative retinal ablation treatment were evaluated to establish factors influencing the surgical outcome. The criteria for success included a postoperative intraocular pressure (IOP) of less than or equal to 21 mmHg and maintenance of vision.

Results: The success rate was 62.1% at 1 year, 52.9% at 2 years, 43.1% at 3 years, 30.8% at 4 years, and 10.3% at 5 years. The main causes for failure were loss of light perception in 48% of eyes (29/60), progression to phthisis bulbi in 18% (11/60), and encapsulation of the filtering bleb in 10% (6/60). The long-term surgical outcome was significantly better in patients older than 55 years of age (P = 0.048) and in those with a preoperative visual acuity equal to or better than 6/60 (P = 0.019). Eyes with neovascular glaucoma secondary to diabetic retinopathy had a better prognosis than those with a central retinal vein occlusion (P = 0.003).

Conclusion: Although the IOP can be significantly reduced after Molteno implantation, this study suggests that in severely compromised eyes with neovascular glaucoma the main advantage of Molteno implantation is pain relief and avoidance of enucleation.