Intravitreal triamcinolone for macular edema secondary to perfused central retinal vein occlusion

Central retinal vein occlusion (CRVO) is an important cause of vision loss. The 15-year cumulative incidence of CRVO was 0.5% in the Beaver Dam Study. Macular edema is a common cause of visual loss in CRVO. There is no proven treatment for macular edema from CRVO. Grid laser treatment showed anatomical improvement in CRVO study, but was not associated with visual improvement. Currently observation is considered standard of care in the management of macular edema secondary to CRVO. SCORE Study evaluated 4 mg and 1 mg triamcinolone acetonide (TA) injection against observation in a randomized clinical trial.

Methods: 271 patients with nonischemic CRVO were randomized to 4 mg or 1 mg intravitreal triamcinolone or observation. Mean duration of CRVO was 4 months, 40% had macular edema for less than three months. Mean visual acuity was 20/100 (range 20/40 to 20/400). Mean central point thickness by OCT was 659 microns. All eyes had less than 10 disk areas of capillary nonperfusion by fluorescein angiogram. Repeat injections were given every four months, if needed and patients were followed for at least one year.

Results. Both TA groups received an average of 2 injections prior to month 12. The percentage of patients gaining 3 or more lines of vision was 6.8%, 26.5% and 25.6% in observation, 1 mg and 4 mg TA groups respectively. Compared to a mean loss of vision of 12 letters in the control group, both TA groups had a mean loss of 1.2 letters of vision at 12 months. Percentage of patients losing three or more lines of vision was 44%, 25.3% and 25.6% respectively in observation, 1 mg and 4 mg TA groups respectively. All three groups had similar decrease in central point thickness by OCT. 35% and 20% eyes in 4 mg and 1 mg TA group respectively required IOP lowering medications. About 33% and 4% eyes in 4 mg and 1 mg TA group required cataract surgery by 24 months.

Conclusion: Both 4 mg and 1 mg TA intravitreal injections were superior to placebo. 1 mg TA was safer than 4 mg. About a quarter of patients in both TA groups gained three or more lines of vision, similar number lost three or more lines of vision and half the patients had central point macular thickness at 12 months. These results indicate that there is a need to develop a better treatment for macular edema caused by CRVO.