Abstract
Abstract: :
Purpose: To evaluate transpupillary thermotherapy (TTT) as a treatment for occult choroidal neovascularization in age-related macular degeneration (AMD). Methods: This prospective study comprised 109 patients referred for occult CNV in exudative AMD. Fluorescein angiography (FA) at baseline disclosed 51 eyes with occult CNV and 58 eyes with minimally classic CNV. Visual acuity (VA) was assessed using the ETDRS logMAR chart. TTT was carried out with a diode laser (810 nm, power 550-800 mW for a 3 mm spot, duration 60 sec). Follow-up included clinical examination with biomicroscopy and FA at 2-3 and 6 months. Results: In the entire case material (n=109), the mean preoperative VA was 20/100 (49.3 letters) and postoperative VA 20/160 (40.8 letters) yielding a decay of 8.5 letters. Eyes with purely occult CNV (n=51) lost on average 4.8 letters (from 20/125 to 20/160), whereas those with minimally classic and occult CNV lost 11.8 letters (from 20/100 to 20/160) (p=0.016). TTT was delivered on average 1.3 times to the former group, 1.6 times to the latter one. In occult CNV the VA improved in 14% and deteriorated in 31%, as compared to 3% and 48%, respectively, in the minimally classic group. The proportion of eyes losing at least 15 letters was 22% in the occult versus 38 in the minimally classic group. A subgroup of minimally classic and occult lesions with a greatest linear dimension of ≷3.o mm responded poorly in this study setting. Stabilization of VA was achieved in 69% of the occult and in 52% of minimally classic CNV, in most cases concomitant with regression of fluorescein leakage to staining only. Conclusion: This pilot study indicates that eyes with purely occult CNV respond significantly better to TTT than those with minimally classic and occult CNV. This difference was most pronounced when the minimally classic and occult lesion had a greatest linear dimension exceeding 3.o mm. To define the most efficacious laser power and optimal treatment intervals further evaluation is warranted. A randomized controlled trial is in progress.