Transpupillary thermotherapy (TTT) for age-related macular degeneration (AMD) – Is it time to say good-bye?

Purpose

To evaluate the effectiveness of transpupillary thermotherapy (TTT) for the closure of classic and occult subfoveal choroidal neovascularization (CNV) and to discuss whether TTT is a useful treatment modality for age-related macular degeneration (AMD).

Materials and methods

The present paper is a retrospective review of the clinical results from a patient group which was treated with TTT in the University Eye Clinic in Mainz. From January 2000 to December 2002, a total of 20 eyes of 20 patients with subfoveal CNV (due to AMD in 16 eyes, due to pathologic myopia in 4 eyes) received TTT. The procedure was delivered using an infrared diode laser at 810 nm, equipped with a modified slit-lamp adapter with an adjustable beam width of 1.2, 2.0 and 3.0 mm. The spot size was selected so that the treatment beam entirely encompassed the lesion. For a 3 mm spot size, up to 800 mW was delivered to the treatment area using a wide-field contact lens. Power was adjusted in such a way that a barely detectable, light-gray appearance of the lesion was seen after 60 s. Patients were seen in follow-up at 6–8 weeks and re-treatment was considered at 12 weeks postoperatively, if persistence or worsening in the leakage of the lesion was observed.

Results

Twenty eyes with subfoveal CNV were treated with TTT and the healing process was followed for at least 6 months. After an average of 2.5 treatment sessions in 14/20 eyes, a rapid decline of CNV activity was observed with resolution of subretinal fluid accompanied by reduction of central scotoma and a significant relief of metamorphopsia. Four eyes with classic subfoveal CNV, due to pathologic myopia, showed closure of the CNV and no visual loss (more than 2 lines) in all cases. In the 16 eyes with occult subfoveal CNV in AMD, closure of the neovascular membrane was achieved in 10/16 eyes leading to a visual stabilization (within 2 lines) during the 6 months follow-up. Six of 16 eyes with AMD became legally blind despite repeated TTT treatment sessions (mean: 4.6 sessions; range: 3–6 sessions). A loss of central vision was due to persistence of macular leakage accompanied by choroidal bleeding, atrophy of the retinal pigment epithelium or progressive subfoveal fibrosis.

Conclusion

The results from this retrospective study demonstrate that occlusion of the neovascular membranes could be observed after TTT for subfoveal CNVs in AMD, as well for highly myopic eyes. Review of the literature shows that the success rate of TTT in AMD (60% after 6 months) is in accordance with the natural progression of occult CNVs in AMD.