Jonathan Lam, Geoffrey Chan, William H Morgan,Martin Hazelton, Brigid Betz-Stablein, Dao Yi Yu

Purpose:
The retinal tissue characteristics associatedwith venous pulsations in the human eye remainsunknown. Using modern techniques which map thelocation and amplitude of venous pulsations, weexamined the physical properties of the human retinalveins at sites of pulsation.

Method:
365 locations were analysed from 25normal human eyes. Video recordings of venous pul-sations centered upon the optic disk were recorded.Green channel densitometry measurements thatre?ect haemoglobin absorption timed to cardiac cyclewas used to calculate a densitometry map re?ectingthe amplitude of pulsation at individual locations. Sur-rounding tissue characteristics (distance to cup margin,vessel length from pulsation point to vein exit, tissuethickness overlying vein, proximity to artery, and veindiameter) were quantitatively studied on correspond-ing ocular coherence tomography scans. Comparisonswere made between high and low amplitude venouspulsation sites.

Results:
Increased venous pulsation amplitudes wereassociated with larger ODF (p = 0.043), increasingvenous diameter (p = 0.003) and decreasing cupmargin distance (p = 0.001). There was no signi?cantcorrelation of venous pulsation amplitude to tissuethickness or proximity to retinal artery (bothp > 0.188).

Conclusion:
Tissue thickness overlying the vein andother tissue relations had no detectable effect uponpulsation. The cup margin was a peak area of veinpulsation which may represent altered haemody-namics secondary to pulse wave re?ection, induced bychange in vein direction at the cup edge. Site ofmaximal venous pulsation appears to be determinedby ?uid dynamic factors and venous geometry.