[Analysis of visual prognosis and correlative factors in retinal vein occlusion]

Abstract

Objective: To investigate the visual prognosis, risk factors, complications and the causes of visual deterioration in patients with various types of retinal vein occlusion (RVO).

Methods: Nine hundred and forty-four eyes of 913 patients with various types of RVO were analyzed. The age range of patients was 15 - 89 years (average 52.8 +/- 11.9), and the average follow-up was 20.7 months. The data of the patients were studied by SPSS software.

Results: (1) RVO was classified into central RVO (CRVO) in 406 eyes of 391 cases (43.0%), hemi-RVO (HRVO) in 60 eyes of 60 cases (6.4%) and branch RVO (BRVO) in 478 eyes of 462 cases (50.6%). (2) They were subdivided into ischemic type in 633 eyes (67.1%) and non-ischemic type in 311 eyes (32.9%). (3) The visual prognosis: the average initial visual acuity (VA) in CRVO, HRVO and BRVO was 0.36, 0.38 and 0.40 respectively. The average final VA was 0.40 in CRVO (P > 0.05), 0.50 in HRVO (P > 0.05) and 0.58 in BRVO (P < 0.05). (4) The initial VA and prognosis: there was close relationship between initial VA and visual prognosis. If the initial VA >/= 0.5, the final acuity maintained >/= 0.5 in 70.6% in CRVO, 75.0% in HRVO and 84.9% in BRVO. The patients with initial VA </= 0.l had final VA worse than 0.1 in 66.2% of CRVO, 35.7% of HRVO and 25.3% of BRVO (P < 0.01). (5) Low vision and the rate of blindness in RVO: Among the 205 eyes with low vision (21.7%), there were 27.6% with CRVO, 31.7% with HRVO and 17.2% with BRVO (P < 0.01). Among the 160 eyes with blindness (16.9%), There were 27.6% with CRVO, 11.7% with HRVO and 8.6% with BRVO (P < 0.01). (6) The visual prognostic comparison between ischemic type and non-ischemic type: there were 189 of 633 eyes with ischemic type (29.9%) and only l6 of 311 eyes with non-ischemic type (5.1%) had low vision. In the ischemic type, 157 eyes had blindness (25.1%) and 3 eyes with non-ischemic type (1.0%) had blindness (P < 0.01). (7) Risk factors of RVO were hypertension (57.8%), arteriosclerosis (67.4%), high blood viscosity (24.6%), diabetes (6.2%) and primary glaucoma (1.5%). (8) Complications of RVO: cystoid macular edema (CME) 46.7%, retinal neovascularization (RNV) 21.5%, vitreous hemorrhage 11.4% and neovascular glaucoma (NVG) 9.6% (39/406) in CRVO and 1.7% (1/60) in HRVO. (9) Low vision caused by CME was 37.9%, and RNV 29.9%; blindness in CME 19.5% and RNV 23.0%. In 40 eyes with NVG, the final VA was worse than 0.05 in 38 eyes (95.0%).

Conclusion: The rate of blindness of RVO is high, and the visual prognosis of ischemic type is worse. There is close relationship between the level of initial VA and visual prognosis. CME, RNV and NVG are important causes of blindness.