FOVEAL AVASCULAR ZONE IN MACULAR BRANCH RETINAL VEIN OCCLUSION

The mean area of the foveal avascular zone (FAZ) in normal subjects wa s reported as 0.231 mm(2) to 0.405 mm(2) using fluorescein angiography . The FAZ enlarges in vaso-occlusive diseases, especially diabetic ret inopathy, sickle cell retinopathy, talc retinopathy and branch retinal vein occlusion. In the present study the FAZ of 20 patients affected by macular branch retinal vein occlusion (MBRVO) was compared with the FAZ of 41 control subjects. The FAZ mean area was 0.56 +/- 0.34 mm(2) SD in the MBRVO group, while 0.26 +/- 0.07 mm(2) SD in the control gr oup, with a statistically significant difference (p < 0.001). The FAZ mean perimeter was 4.77 +/- 1.90 mm SD in the MBRVO group, and 2.36 +/ - 0.32 mm SD in the control group, with a statistically significant di fference (p < 0.001). Taking into account the MBRVO group, a statistic al correlation was found between visual acuity impairment and FAZ enla rgement (p = 0.02), but not between visual acuity impairment and macul ar edema (p = 0.41). In 14 cases (70%) secondary avascular microzones located in the macular sector correspondent to MBRVO were also evident . MBRVO causes an irregular enlargement of the FAZ which seems to repr esent the most important feature related to visual acuity impairment.