Krypton vs Argon Laser Photocoagulation for Diabetic Retinopathy Neovascularization Regression
Data Collection
Cardiovascular Diseases+14
+ Diabetes Mellitus
+ Diabetic Angiopathies
Treatment Study
Summary
Study start date: December 1, 1984
Actual date on which the first participant was enrolled.The KARNS study is a large clinical trial that aims to compare the effectiveness of two types of laser treatments, argon and krypton, in treating diabetic retinopathy, a condition that affects the eyes of people with diabetes. Specifically, the study focuses on a complication called neovascularization on the disc (NVD), where new, abnormal blood vessels grow on the optic disc. The main advantage of the krypton laser is that it can penetrate blood and may be more effective in making burns in the pigment epithelium in eyes with vitreous hemorrhage. The study involves patients with diabetic retinopathy and NVD of one-third disc area or greater. The goal is to determine if the krypton laser can be as effective as the argon laser in causing regression of diabetic neovascularization, but with fewer side effects, such as less loss of central visual acuity. In this study, participants are randomly assigned to receive either argon or krypton laser scatter photocoagulation. The treatment involves placing 1,600 to 2,000 burns of moderate intensity and 500 microns in size at the retina. These burns are applied to the retinal periphery, keeping a safe distance from the center of the fovea and the margin of the optic disc. After the initial examination, a baseline examination and fundus photographs are obtained within 1 week before the application of photocoagulation. Study follow-up visits occur at 3 months and 1 year after entry into the study, with additional visits scheduled as clinically necessary. The primary endpoint is the regression of NVD, as assessed on the 3-month visit stereo fundus photographs of the disc, to less than one-third disc area in extent.
Protocol
This section provides details of the study plan, including how the study is designed and what the study is measuring.Treatment Study
Eligibility
Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.Any sex
Biological sex of participants that are eligible to enroll.From 18 to 79 Years
Range of ages for which participants are eligible to join.Healthy volunteers not allowed
If individuals who are healthy and do not have the condition being studied can participate.Conditions
Pathology
Criteria
Men and women ages 18 through 79 diagnosed with diabetes mellitus and who had neovascularization on the optic nerve head (NVD) were eligible. NVD in one or both eyes of each patient had to be greater than or equal to DRS Standard Photograph 10A. NVD was defined as new vessels on the surface of the retina, further forward in the vitreous cavity over the disc, or within one disc diameter of the disc in any direction. Patient's ocular media must have been clear enough for fundus photography, which allowed the extent of neovascularization on the optic nerve head to be assessed. (If vitreous hemorrhage or other media opacity prevented adequate visualization of the neovascularization, it would greatly impair the ability to assess the effect of photocoagulation.) Another requirement for patient eligibility was the presence of an area of at least three quadrants of the retina in which full argon or krypton laser panretinal photocoagulation could be placed. (Vitreous hemorrhage and/or traction retinal detachment that interfered with treatment was less than one quadrant in extent.)