Abstract
Purpose: :
To test the hypotheses that micro-irregularities in retinal vessel structure using Fast Fourier Transform (FFT) analysis of continuous retinal vessel diameter recordings is firstly different in subjects with coronary artery disease (CAD) compared to smokers and normals, and secondly varies with age.
Methods: :
Two groups comprised of 21 smokers (mean age 32 yrs, ±9) and 30 CAD patients (mean age 56 yrs, ±9); groups 1 and 2 respectively, were compared with age-matched control groups (control 1: 30 individuals, mean age 36 yrs, ±10 and control 2: 30 individuals, mean age 53 yrs, ±9). All individuals underwent dynamic retinal diameter assessment using the retinal vessel analyser (RVA) (Imedos GmbH, Germany). Systemic blood pressure was measured using sphygmomanometry and intraocular pressure using the TonopenXL (PMS Instruments, UK). FFTs along retinal arteries and veins were obtained at 3 different points using 30 second baseline recordings of retinal artery diameter (RAD) and retinal vein diameter (RVD).
Results: :
There was no difference in RAD between the smokers, 122µm ±15 and age-matched controls, 120µm ±20 (p=0.369). Similarly no difference was found between CAD (group 2) patients and controls (118µm ±16 and 114µm ±18). The RVD was increased in smokers and CAD patients compared their controls; smokers: 161µm ±16, versus controls 149µm ±17 and CAD: 157µm ±22 versus controls 147µm ±17. The increase in RVD in smokers was significant (p=0.004). No defined frequency calculated by FFT was detectable in either retinal arteries or veins in participants who smoked or who had CAD compared to their respective control groups.
Conclusions: :
The lack of detectable pulsation frequency would indicate changes in retinal blood vessel wall properties and their dynamic behaviour in the regulation of blood flow. This could be explained by a loss of endothelial function occurring with age, smoking and the presence of CAD. These changes may be a surrogate marker for vascular pathologies.
Keywords: retina • pathology: human • retina