Citations: CVOS Group. Evaluation of Grid Pattern Photocoagulation for Macular Edema in Central Vein Occlusion: The Central Vein Occlusion Study Group M Report. Ophthalmology, Volume 102, Issue 10, 1425 - 1433
To evaluate the visual outcomes of macular grid laser photocoagulation for the treatment of macular edema in CVO patients with a visual acuity of 20/50 or worse.
Multicenter, randomized, controlled trial
3 years or until end of the study
- Central Retinal Vein Occlusion (CVO) as noted on fundus photographs (4 quadrants of retinal hemorrhages and venous dilation)
- CVO of at least 3 months’ duration
- Macular edema involving fovea as determined by the Reading Center on FA
- VA of 20/50 to 5/200 (as measured by ETDRS)
- No improvement in VA on 2 consecutive visits prior to entry
- IOP of < 30 mm Hg
Major inclusion criteria:
- Previous treatment with laser photocoagulation
- Concurrent ocular disease that may affect VA over study period
- Presence of diabetic retinopathy (either eye), vitreous hemorrhage, retinal neovascularization or other retinal vascular diseases in study eye
- Peripheral anterior synechiae
- Inability to discontinue heparain/warfarin for duration of study
- Aphakia, pseudophakia or significant lens opacity
- Macular non perfusion noted on FA
Major exclusion criteria:
Randomization scheme and interventions:
- (a) Grid macular argon laser photocoagulation
- (b) No laser photocoagulation
- Method of Grid Laser: The settings were the following: spot size 100 microns, moderate intensity, 0.1 second duration, 0.5-1 burn width apart. FA guided laser over area of capillary leakage within 2 disc diameters of the foveal center was performed; laser could not extend beyond 2 disc diameters from fovea or within foveal avascular zone.
- Fluorescein angiograms were obtained at baseline, 4 month visit, and annually for 3 years. Fundus photographs were taken at each visit and 48 hours after treatment. If VA improvement was 9 letters or less and treatable macular edema was still present on angiography, then the patient was retreated.
- Study Duration: 3 years or until end of the study
- Visual Acuity (VA)— as measured by ETDRS
- 155 patients (77 grid laser and 78 controls-no treatment)
- No significant differences in mean VA or change in VA between grid laser and observation at any follow up visit (baseline, 4 months, each annual visit up to 3 years).
NOTABLE SECONDARY OUTCOMES
- 23 of 77 patients (30%) required a retreatment
- No difference in VA outcomes in patients with < 1 year versus > 1 year duration of CRVO
- There was a statically reduction in macular edema in the treated versus untreated eyes (31% versus 0% with complete resolution).
- There was an age interaction based on treatment: VA deteriorated in patients > 60 years that were treated and VA tended to improve in younger patients that were treated. However, this interaction went away after controlling for other potential interactions.
- None reported
- Grid argon laser photocoagulation does not improve visual acuity outcomes in CVO patients with macular edema and a VA of 20/50 or worse compared to observation