Effect of axial length on retinal vascular network geometry.
OBJECTIVE
To explore the association between axial length and retinal vascular network geometry (arteriovenous diameter ratio [AVR], arteriolar branching angles, and junctional exponents).


METHODS
Prospective, cross-sectional study.


METHODS
Patients were recruited from a pseudophakic population that had preexisting axial length measurements. Mean arterial blood pressure and previous medical history were recorded. Fundal photographs were taken. Digital image analysis was used to determine the AVR, mean arteriolar bifurcation angle, and junctional exponent for each subject.


RESULTS
In total, 52 subjects were analyzed. Axial length had no association with AVR (R = -0.01, P = .941), mean angles at arteriolar bifurcations (R = -.134, P = .342), or junctional exponents (R = .003, P = .982). However, increased axial length was associated with a trend for lower measured retinal venular and arteriolar diameters (R = -.28, P = .04 and R = -.23, P = .10, respectively). Junctional exponents correlated with both the AVR (R = .32, P = .019) and vascular bifurcation angles (omega) (R = .317, P = .022).


CONCLUSIONS
Increased axial length is associated with narrowing of both arteriolar and venular diameters, but not on the AVR, or vessel junctions. Future studies exploring the influence of systemic disease on retinal vascular topography do not need to consider axial length as a potential confounding variable when utilizing measures such as AVR or vessel junctions. Vascular arteriolar junctional exponents may serve as a good measure of overall altered retinal vascular geometry in cardiovascular disease.
Patton
Niall
N
Sir Charles Gairdner Hospital, Perth, Western Australia. niallpatton@hotmail.com
Maini
Rishma
R
MacGillivary
Tom
T
Aslam
Tariq M
TM
Deary
Ian J
IJ
Dhillon
Baljean
B
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D001837:Body Weights and Measures; D002318:Cardiovascular Diseases / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005123:Eye / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000379:methods; D011446:Prospective Studies; D012039:Regional Blood Flow; D012171:Retinal Vessels / Q000503:physiopathology*