Abstract
Abstract: :
Purpose: To assess retinal sensitivity following the use of transpupillary thermotherapy (TTT) for treating occult subfoveal choroidal neovascularisation (NVC) secondary to age-related macular degeneration. Method: 40 eyes in 40 patients with occult NVC were treated with TTT. Preoperative tests were logMAR visual acuity (VA), fluorescein angiography, contrast sensitivity and computerised static perimetry. For treatment we used an 810-nm diode laser (IRIDEX Medical Instruments, Mountain View, CA) with a slit lamp adapter; power setting 320-800 mW; diameter 1.2, 2, 3 mm. We set a spot diameter suitable for covering the entire angiographically visible lesion. We delivered 800 mW through a contact lens for a spot diameter of 3 mm, reducing the energy parameters accordingly for a smaller spot diameter. Static perimetry was used to assess retinal sensitivity (Octopus 1-2-3, V14.16. Interzeag, Schlieren, Switzerland), analysing a total of 81 points limited to the central 10° in two different stages. Taking into account VA and leakage after treatment, we established the following efficacy parameters: Healing (disappearance of exudation with VA improved or unchanged), success (persistence of exudation with >VA or disappearance of exudation with VA diminished <1 line), failure (vision diminished >1 line). Follow-up appointments were scheduled at 1, 3, 6 and 9 months. In cases of persistent leakage we repeated the treatment after a minimum interval of 3 months. Results: Mean sensitivity: The mean increase was +3.46 dB (20 eyes: 50%) and -4.62 dB (20 eyes: 50%). Mean defect: The mean increase was +4.54 dB (20 eyes: 50%) and -3.42 dB (20 eyes: 50%). Loss of variance and loss of corrected variance: Worsened in 31 eyes (78%). The means were 15 dB and 11.6 dB respectively. The mean increase in contrast sensitivity was +0.26 (18 eyes: 45%) and -0.4 (22 eyes: 55%). According to our efficacy parameters, the results were healing in 16 eyes (40%), success in 12 eyes (30%) and failure in 12 eyes (30%). Conclusions: TTT deepens the scotoma caused by NVC accompanied by a reduction in subretinal exudation. This effect may result in stabilisation or improvement of average retinal sensitivity.
Keywords: choroid: neovascularization • laser • perimetry