Abstract
Purpose:
The force required to induce venous pulsation is a significant predictor of glaucoma progression. It is not known whether alterations in intraocular pressure affect these vein pulsation properties.
Methods:
Glaucoma and suspect patients had two retinal vein ophthalmodynamometric force (ODF) measurements at least 40 days apart. All subjects had Humphrey visual fields, scanning laser tomography, central corneal thickness (CCT) and IOP recorded at the initial visit. The time intervals between ODF measurements and age were calculated. The upper and lower hemivein ODF was measured. The change in ODF and change in IOP was calculated. Data from each eye was analysed using a linear mixed model with random factors to account for left and right eye, upper and lower correlation.
Results:
Thirty two subjects fulfilled the criterion (20 females). The mean time interval between measurements was 14.3 (± 9.9) months and mean age was 60 (± 11 years). Multivariate linear regression analysis demonstrated that change in mean ODF was significantly associated with change in intraocular pressure (coefficient = 0.55 mmHg/mmHg, p=0.0009). Other parameters: central corneal thickness (p=0.31), initial IOP (p=0.79), hemi-neuroretinal rim area (p=0.26), age (p=0.66), mean hemifield defect (p=0.33) and time interval (p=0.38) were not significantly associated with change in ODF.
Conclusions:
Change in ODF is strongly associated with change in IOP such that a reduced intraocular pressure is associated with a subsequent reduction in venous ODF. This implies that favourable changes in central retinal vein properties are occurring when intraocular pressure is reduced.
Keywords: 627 optic disc •
436 blood supply •
568 intraocular pressure