Axial Lenth of Eye as a Risk Factor of the Branch Retinal Vein Occlusion

ABSTRACT

Branch retinal vein occlusion(BRVO), along with central retinal vein occlusion, is second only to diabetic retinopathy as a cause of retinal vascular disease. It has been suggested that eyes with shorter axial length have smaller lamina cribrosa and a narrower scleral canal through which the central retinal vein and artery could pass, causing physical blockage in the vein which predisposes to thrombus formation. The subsequent narrowing of the venous lumen will lead to trubulence. reduced flow, venous stasis and thrombus formation at the level of the arteriovenous crossing. This study was conducted to determine whether there was any difference between the axial lengths of eyes with BRVO and those of control eyes. The axial lengths of the eyes in the group of 37 patients with a unilateral BRVO was compared with those of eyes in the control group. The BRVO group consisted of 23 male and 14 female patients and their mean ages were 61.5+/-7.0 years(51~75years) in male and 63.7+/-7.0 years(52~76years) in female. The control group consisted of 46 male and 28 female patients and their mean ages were 62.5+/-6.5 years(50~73years) in male and 63.9+/-6.1 years(52~75years) in female. The mean axial length of eyes of the BRVO group was 23.08+/-0.57mm(21.92~24.19mm) in male and 22.71+/-0.65mm(21.08~24.00mm) in female. The mean axial length of control eyes was 23.74+/-0.73mm(22.46~25.24mm) in male and 23.18+/-0.81mm(21.62~24.76mm) in female. The difference between the mean axial length of eyes of the BRVO group and that of control eyes was statistically significant(p<0.05). In conclusion, the short axial length may play as a risk factor in the occurrence of a BRVO.