AIM: To investigate the changes of choroidal thickness in patients with severe non-proliferative diabetic retinopathy(NPDR)after vitreous injection of ranibizumab, and to analyze the relationship between the thickness of choroid and the visual acuity of the patients.

METHODS: Eighty patients with severe non-proliferative diabetic retinopathy were selected from January 1, 2014 to January 1, 2017. All patients were divided into observation group and control group according to the random number table, 40 cases in each group. The control group was treated in a conventional manner, and the observation group was injected with ranibizumab in the vitreous. The thickness of the choroid in the macular area and the thickness of the retinal neuroepithelium in the macular area were compared between the two groups before and after treatment. The changes of the corrected visual acuity were analyzed at 1mo before and after treatment. The relationship between the thickness of the choroid and the thickness of the retinal neuroepithelium and the best corrected visual acuity were compared. The complications and adverse events were compared between the two groups after 6wk of treatment.

RESULTS: The thickness of the choroid and the retinal neuroepithelium in the macular area before were 219.57±51.24μm and 474.76±95.56μm, respectively, in the observation group and the control group, 217.56±50.36μm and 473.27±96.48μm, respectively. The thickness of the choroid and the thickness of the retinal neuroepithelium in the macular area after treatment were 180.15±42.06μm and 382.18±84.26, 202.48±48.28μm and 407.88±44.25μm, respectively. The difference between the two groups was statistically significant(P<0.05). The best corrected visual acuity in the observation group and the control group were 0.47±0.19 and 0.53±0.25 respectively(P<0.05). There was a positive correlation between the choroidal thickness and the best corrected visual acuity in the macular fovea(regression coefficient=1.12, S=0.48, OR=1.376, P<0.05). There was a positive correlation between retinal neuroepithelial thickness and best corrected visual acuity in the macular area(regression coefficient =0.95, S=0.27, OR=1.020, P<0.05). There were 2 eyes(5%)with subconjunctival hemorrhage, 1 eyes(2.5%)of glaucoma, 1 eyes(2.5%)of vitreous hemorrhage, 0 of choroidal detachment, retinal detachment in 0 in observation group at 6wk after treatment. There were 4 eyes(10%)with subconjunctival hemorrhage, 2 eyes(5%)of glaucoma, 2 eyes of vitreous hemorrhage(5%), 2 eyes of choroidal detachment(5%), retinal detachment in 2 eyes(5%)in the control group, and the difference between the two groups on the complications and adverse reactions was statistically significant(P<0.05).

CONCLUSION: The choroidal thickness of patients with macular edema in severe non-proliferative diabetic retinopathy is correlated with the best corrected visual acuity. Intravitreal injection of ranibizumab can effectively reduce the macular fovea choroidal thickness, reduce macular edema and improve vision, and less complications.