Abstract
Purpose: :
To compare three laser photocoagulation techniques for treatment of diabetic macular edema: the modified Early Treatment Diabetic Retinopathy Study (ETDRS) direct/ grid photocoagulation technique and a normal density (a mild macular grid is placed throughout the macula and the microaneurysms are not treated directly) or high density ( increased number of spots to potentially enhace the area of retinal pigment epithelium activation) sub-threshold micro pulsed 810 nm diode laser technique.
Methods: :
In this prospective, double-masked, controlled trial, ninety subjects with previously untreated diabetic macular edema were randomly assigned to receive laser photocoagulation by the modified ETDRS (30 eyes), normal (29 eyes) or high density (31 eyes) micro pulsed technique (Opto FastPulsetm Laser). Visual acuity, fluorescein angiography, and optical coherence tomography (OCT) measurements were obtained at baseline and at 1, 3, 6, and 12 months. As main outcome measures, changes in central macular thickness and visual acuity were measured over a 12-month follow-up. Retreatment was allowed for persistent diabetic macular edema.
Results: :
Central macular thickness decreased by an average of 97 µm in the modified ETDRS group; by 33 µm in the normal density sub-threshold micro pulsed technique (NDSF); and by 146 µm in the high density sub-threshold micro pulsed technique (HDSF). At 12 months mean change in visual acuity was 0 (zero) letter in the modified ETDRS group; 3 letters worse in the NDSF technique group; and 2 letters improved in the HDSF technique group.
Conclusions: :
The findings from our study neither advocate nor support the use of sub-threshold laser treatment of diabetic macular edema, but imply a short-term clinical perfomance clearly favoring HDSF technique over the modified ETDRS technique for the anatomic and functional aspects of improvement tested in this investigation. A rationale for the HDSF as a preferable approach is suggested and as experience grows guided by optimized treatment guidelines and comprehensive trials, the precise role of sub-threshold laser treatment may become more defined.
Clinical Trial: :
www.clinicaltrials.gov NCT00552435
Keywords: laser • diabetic retinopathy • edema