Transpupillary thermotherapy (TTT) for the treatment of choroidal neovascularisation

Abstract

Aim: To assess the effectiveness of transpupillary thermotherapy (TTT) for the treatment of classic and occult choroidal neovascularisation (CNV).

Method: In a retrospective, case selected, open label trial 44 eyes of 42 patients with CNV secondary to age related macular degeneration (ARMD) were studied. 44 eyes with angiographically defined CNV were treated with diode laser (810 nm) TTT. Laser beam sizes ranged between 0.8 and 3.0 mm and power settings between 250-750 mW. Treatment was given in one area for 1 minute, the end point being no visible change, or a slight greying of the retina. Outcome was assessed with Snellen visual acuity and clinical examination; in 24/44 patients angiographic follow up was available.

Results: 12 predominantly classic CNV and 32 predominantly occult membranes were followed up for a mean of 6.1 months (range 2-19). Mean change in vision for classic membranes was -0.75 (SD 1.75) Snellen lines and occult membranes was -0.66 Snellen lines (2.1) (p>0.05). Predominantly classic membranes were closed in 75% (95% CI: 62.5-87.5) of eyes, remained persistent in 25% (95% CI: 12.5-37.5); no recurrences occurred. Predominantly occult membranes were closed in 78% (95% CI: 70.1-85.3) of eyes, remained persistent in 12.5% (95% CI: 6.6-18.5), and were recurrent in 5.1% (95% CI: 4.2-14.3).

Conclusions: Transpupillary thermotherapy is a potential treatment for CNV. It is able to close choroidal neovascularisation while maintaining visual function in patients with classic and occult disease. Further trials of TTT are needed to compare this intervention with the natural history and other treatment modalities.

Figure 1

(Top left and right) Colour and fluorescein images showing a small classic juxtafoveal membrane. (Bottom left and right) Colour and fluorescein images following TTT with resolution of the membrane; the patient's initial vision improved from 6/12 to 6/9 3 months after treatment.

Figure 2

(Top left and right) Colour and fluorescein images showing an occult subfoveal membrane. (Bottom left and right) Colour and fluorescein images following TTT, with complete closure of the CNV. The patient's vision was stabilised 3 months following treatment.

Figure 3

(Top left and right) Colour and fluorescein images showing an occult subfoveal membrane with extensive subretinal haemorrhage. (Bottom left and right) Colour and fluorescein images showing resolution of the CNV and absorption of subretinal haemorrhage 6 weeks following TTT treatment. The patient's vision improved from 6/60 to 6/24.

Figure 4

(A) Change in visual acuity following transpupillary thermotherapy for classic CNV. There was no significant deterioration in vision between the pretreatment group (VA = 6/32.4) and the post-treatment group (6/40) (p=0.1). (B) Change in visual acuity following transpupillary thermotherapy for occult CNV. There was no significant deterioration in vision between the pretreatment group (VA = 6/24.0) and the post-treatment group (6/26.4) (p=0.1).

Figure 5

Kaplan-Meyer estimates of the cumulative proportion of eyes treated with TTT with moderate visual acuity loss (⩾ 3 Snellen lines).