PT  - JOURNAL ARTICLE
AU  - A Harris
AU  - Y Ishii
AU  - H S Chung
AU  - C P Jonescu-Cuypers
AU  - L J McCranor
AU  - L Kagemann
AU  - H J Garzozi
TI  - Blood flow per unit retinal nerve fibre tissue volume is lower in the human inferior retina
AID  - 10.1136/bjo.87.2.184
DP  - 2003 Feb 01
TA  - British Journal of Ophthalmology
PG  - 184--188
VI  - 87
IP  - 2
4099  - http://bjo.bmj.com/content/87/2/184.short
4100  - http://bjo.bmj.com/content/87/2/184.full
SO  - Br J Ophthalmol2003 Feb 01; 87
AB  - Aim: To determine if perfusion per unit tissue volume of retinal nerve fibre layer and optic nerve head in the inferior sector is lower than in the superior sector. Methods: Heidelberg retinal tomogram (HRT) for topographic measurement of optic nerve head and retinal nerve fibre layer and Heidelberg retinal flowmeter (HRF) for retinal blood flow were performed on 19 normal healthy subjects. Measurements from the superior and inferior sectors were compared. The perfusion/nerve fibre ratio (PNR); the blood flow per unit retinal nerve fibre tissue volume, was calculated in each sector with a formula; HRF flow measurements divided by HRT measurements. Results: Retinal nerve fibre layer thickness in the inferior retina was significantly higher than in the superior retina (p<0.05). There were, however, no differences in retinal blood flow between the superior and inferior retinal sectors. The PNR in the inferior sector were significantly lower than in the superior sector (p=0.047 for HRF mean flow/rim volume and p = 0.0282 for HRF 75th percentile flow/rim volume). Conclusions: The inferior sector of retinal nerve fibre layer and optic nerve head may have lower blood flow per unit nerve tissue volume compared to the superior sector. This result suggests that the inferior sector is more vulnerable to elevated intraocular pressure (IOP) and ischaemic insults in glaucomatous optic neuropathy.