Strontium plaque irradiation of subfoveal neovascular membranes in age-related macular degeneration.

PURPOSE

To determine the effect of focal strontium-90 plaque radiotherapy on subfoveal choroidal neovascularization in patients with age-related macular degeneration.

METHODS

Twenty patients with age-related macular degeneration, presenting with a recent subfoveal neovascular membrane, were treated with local episcleral radiotherapy using a strontium-90 applicator. The applicator was applied to the sclera under the macular region and held there tightly for 54 min to obtain a dose of 15 Gy at a depth of 1.75 mm. The main parameters evaluated at follow-up after 3, 6 and 12 months were visual acuity and changes in fluorescein angiography. Twelve untreated patients with the same criteria were followed as controls.

RESULTS

Early effects of radiation could be seen at 3 months, but became more obvious after follow-up for 6 and 12 months. At 6 months, regression of the choroidal neovascularization was detected in 14/19 patients (74%) as a decrease in the size of the lesion or as diminished leakage in late-phase fluorescein angiography. Likewise, in 14/19 patients (74%) at 12 months the neovascular membrane was partially or totally occluded. In all patients showing regression of the choroidal neovascular membrane, the neurosensory detachment had also dried. Visual acuity was unchanged (within 1 line) or improved in 11/20 (55%) and 9/20 (45%) treated patients after 6 and 12 months, respectively. In the controls, the choroidal neovascularization had increased in size in 9/12 patients (75%) at the last follow-up (mean 12.0 months). Visual acuity was unchanged in 3/12 patients (25%).

CONCLUSION

Local low-energy beta irradiation with a strontium-90 applicator can induce regression of choroidal neovascularization. The effect of irradiation is seen as a decrease in the size of the choroidal neovascular membrane and disappearance of the neurosensory detachment and exudates.