Abstract
Purpose: :
To evaluate the potential of a subthreshold, low irradiance, long exposure duration, large spot size, infrared diode laser (LSDT) for the treatment of diabetic macular edema.
Methods: :
A pilot observational case series of fifteen patients with ischemic or diffuse diabetic macula edema treated with a variable single spot long–pulse 810–nm diode laser infrared radiation adjusted for chorioretinal pigmentation, macular elevation and media clarity (OPTO Dual–Mode, 4.3 mm spot, 60–90 sec, 800 –1200mW, Ocular Mainster–PDT lens). For main outcome measures changes in logMar of best correct visual acuity and central macular thickness obtained using optical coherence tomography were series–measured over a 1–year follow–up. Pre and post–treatment multifocal electroretinogram (mERG), color photography, fluorescein and indocyanine green angiography were evaluated. Potential treatment complications, including retinal phototoxicity, were closed monitored.
Results: :
Three eyes (19%) showed a two–or–more–line improvement in visual acuity over a period of 12 months suggesting a trend towards improved BCVA. Visual acuity remained stable (no change or one–line improvement) in nine treated eyes (56%). The remaining four eyes (25%) showed a decline (equal to one–line worsening or greater) in visual acuity. Fifteen eyes (94%) demonstrated decreased exudation on fluorescein angiography, optical coherence tomography, and/or clinical examination. No clinically or ERG deleterious side effects were observed, although, a transient choroidal ischemia was present in the initial treatment cases when the proper laser parameters were being tested.
Conclusions: :
The findings from our study neither advocate nor support the use of LSDT for the treatment of diabetic macular edema, but do imply that it may be of benefit in the management of poor prognosis–macular edema providing an alternative to conventional laser therapy and merits further evaluation.
Keywords: diabetic retinopathy • laser • macula/fovea