The aim of this study was to investigate the efficacy and safety of intravitreal injection of anti-vascular endothelial growth factor (VEGF) agent——ranibizumab in combination with dexamethasone for cystoid macular oedema (CMO) secondary to central retina vein occlusion (CRVO).

51 patients (51 eyes) with CMO secondary to CRVO diagnosed at Qingdao Eye Hospital of Shandong First Medical University from June 2014 to June 2020 were enrolled. Among of them, 27 cases (27 eyes) were male and 24 cases (24 eyes) were female with the average age of (54.65±13.37)years (ranged from 21 to 83 years) . All of the eyes underwent intravitreous injection of ranibizumab combined with dexame-thasone and performed as needed after treatments according to the extent of CMO. Fundoscopy, best corrected visual acuity (BCVA) and central retinal thickness (CMT) were performed before treatment and after treatment for 1 week, 1 month. Treatment frequency, interval time of repeat treatments and complications were recorded. BCVA and CMT were expressed by ±s. The paired t test was used to compare the changes of BCVA and CMT before and after treatment. Much more attentions were paid to analyze the changes of BCVA, CMT, treatment number during 6 months, repeated measurement data, interval time after treatment for 1 week, 1 months and last follow-up, and compare the efficacy of intravitreal injection of ranibizumab or dexamethasone alone in previous literature reports. Pearson correlation coefficient was used to evaluate the correlation of terminal BCVA and BCVA before and after the first three treatments.

The baseline BCVA was (29.43±17.99)ETDRS letters. BCVA of patients after the first vitreous injection for one week and one month was (43.36±21.85)ETDRS letters and (46.88±20.79)ETDRS letters, respectively, which were both improved. The difference was statistically significant (t=10.94, 10.32; P<0.05). The final BCVA was (45.00±19.10)ETDRS letters, which was improved (15.53±15.34)ETDRS letters than baseline. The difference was statistically significant (t=13.50, P<0.05 ). There were 32 eyes of patients improved in BCVA, 14 eyes stabilized, and 2 eyes decreased. The mean CMT of baseline, and after the first intravitreal injection for 1 week, 1 month was (695.33±204.90)μm, (317.00±71.05)μm, (315.34±66.80)μm, respectively. Compared with the baseline CMT, the difference was statistically significant (t=14.12, 13.43; P<0.05). CMT of patients was (236.51±63.95)μm at final follow-up, which was decreased (458.82±216.83)μm than baseline and the difference was statistically significant (t=16.76, P<0.05). The average number of treatments was (7.19±3.95) and mean interval between injections was (62.24±22.30) d. Serious adverse events such as significant progression of cataracts, intraocular infections, cardiovascular complications were not observed.

Intravitreous injection of Anti-VEGF agent combined with dexamethasone for the treatment of CMO secondary to CRVO was safe and effective in improving BCVA and decreasing CMT. The combined therapy also helps to reduce the treatment frequency and prolong the interval of repeated therapy.