Comparative use of diode and argon laser for panretinal photocoagulation in diabetic retinopathy

The recently introduced semiconductor diode laser is portable, more compact, and cheaper to maintain than other laser systems. It is unclear whether its wavelength characteristics in the near infrared (810 nm) lead to different clinical results of retinal photocoagulation. In a prospective study ten diabetics (3 type I and 7 type II) ranging in age from 26 to 72 years with bilateral proliferative or severe nonproliferative diabetic retinopathy and visual acuity better than 6/18 in both eyes underwent panretinal photocoagulation. One eye was treated with the diode laser, the fellow eye with argon green (514 nm). Follow-up was documented by best-corrected visual acuity, fundus photography and fluorescein angiography. Mean duration of follow-up was 12 months. In neither group was there a significant difference in the response of retinopathy and neovascularization to the treatment, or in the course of visual acuity. Fluorescein angiography revealed the more profound effects of the diode laser in the choroid. Compared to argon laser treatment, patients found diode laser treatment more painful, but appreciated the absence of bright flashes during therapy. Photocoagulation for diabetic retinopathy using the diode laser was as effective as using the argon system in this initial pilot study.