ObjectiveTo observe the short-term efficacy and safety of a new strategy of dexamethasone intravitreal implant (DEX) combined with ranibizumab in the treatment of retinal vein occlusion (RVO) secondary to macular edema (ME) (RVO-ME). MethodsA prospective clinical interventional study. From May 2020 to September 2021, 78 RVO-ME patients with 78 eyes diagnosed in the eye examination of Department of Ophthalmology of The First Affiliated Hospital of Anhui University of Science&Technology were included in the study. Among them, there were 35 males and 43 females, all with monocular disease. Branch retinal vein occlusion (BRVO) was found in 40 patients with 40 eyes; central retinal vein occlusion (CRVO) was found in 38 patients with 38 eyes. According to the treatment strategies, patients were randomly divided into DEX and ranibizumab combination therapy group (initial combination therapy group), DEX monotherapy group and ranibizumab monotherapy group, with 29 eyes, 26 eyes and 23 eyes respectively. Different types of RVO were divided into different treatment groups of BRVO and CRVO. Best corrected visual acuity (BCVA) and frequency domain optical coherence tomography were performed. The BCVA examination was carried out using the international standard visual acuity chart, which was converted into the logarithmic minimum angle of resolution (logMAR) visual acuity during statistics. There were no significant differences in logMAR BCVA (χ2=2.376) and central retinal thickness (CRT) (F=0.052) among the three groups (P＞0.05). After treatment, the patients were followed up every month for 6 months. The changes of BCVA, CRT and the incidence of adverse reactions were observed during follow-up. One-way ANOVA and Kruskal-Wallis H test were used to compare the differences. ResultsDuring the follow-up period, compared with the baseline, the BCVA of the eyes in the initial combination treatment group, DEX treatment group and ranibizumab treatment group were significantly improved (Z=110.970, 90.359, 207.303), and CRT was significantly decreased (F=107.172, 88.418, 61.040), the difference was statistically significant (P＜0.01). At 1, 2, 3, 4, 5, and 6 months after treatment, there were significant differences in the mean changes in BCVA between the initial combined treatment group, DEX treatment group, and ranibizumab treatment group (χ2=34.522, 29.570, 14.199, 7.000, 6.434, 6.880; P＜0.05); 1, 2, 3, and 6 months after treatment, the differences were statistically significant (F=4.313, 7.520, 3.699, 3.152; P＜0.05). The time required to improve BCVA by 0.1 logMAR units in the initial combination treatment group, DEX treatment group, and ranibizumab treatment group was 5.73 (3.21, 8.48), 9.97 (6.29, 18.78), and 20.00 (9.41, 37.89) d, respectively; The time required for CRT to drop to 300 μm was 24.31 (21.32, 26.15), 29.42 (25.65, 31.37), and 29.17 (25.28, 36.94) d, respectively. The BCVA improvement of 0.1 logMAR unit and the time required for CRT to decrease to 300 μm in the eyes of initial combined treatment group were shorter than those in the eyes of DEX treatment group and the ranibizumab treatment group, and the differences were statistically significant (Z=－3.533, －4.445, －3.670, －4.030; P＜0.01). Different BRVO treatment groups: 1, 2, 3, 5, and 6 months after treatment, the mean BCVA changes were significantly different (χ2=24.989, 21.652, 11.627, 7.054, 9.698; P＜0.05); CRVO was different treatment group: 1 and 2 months after treatment, there were significant differences in mean BCVA changes (χ2=11.137, 9.746; P＜0.05). Two months after treatment, there were significant differences in CRT changes between BRVO and CRVO groups with different treatment regimens (F=3.960, 3.722; P＜0.01). The time required to improve BCVA by 0.1 logMAR unit in the eyes of BRVO and CRVO combined treatment group was shorter than that in the eyes of BRVO, CRVO DEX treatment group and the BRVO, CRVO ranibizumab treatment group, and the differences were statistically significant (BRVO: Z=－2.687, －3.877; P＜0.05; CRVO: Z=－2.437, －3.575; P＜0.05). The time required for CRT to drop to 300 μm in the CRVO combined treatment group was significantly shorter than that in the CRVO DEX treatment group and the CRVO ranibizumab treatment group, and the difference was statistically significant (F=6.910, P＜0.010); there was no statistically significant difference between the different BRVO treatment groups (F=1.786, P＞0.05). The number of re-treated eyes in the initial combined treatment group and DEX treatment group was less than that in the ranibizumab treatment group, and the difference was statistically significant (χ2=18.330, 7.224; P＜0.05). The retreatment interval of the eyes in the initial combined treatment group was significantly longer than that in the DEX treatment group and the ranibizumab treatment group, and the difference was statistically significant (P＜0.01). There was no significant difference in the incidence of intraocular hypertension among the initial combined treatment group, DEX treatment group and ranibizumab treatment group (χ2=0.058, P＞0.05). ConclusionsThe new strategy of initial combination therapy with DEX and ranibizumab in the treatment of RVO-ME has a better short-term effect. Compared with the monotherapy group, the retreatment interval is shorter, the visual and anatomical benefits are faster, the efficacy lasts longer, and the safety is better.