Abstract
Purpose :
The loss of retinal venous pulsation is associated with worse glaucoma and greater glaucomatous progression. Photo-plethysmography (PPG) can measure pulse amplitudes, which we use to explore possible relationships between retinal vessel pulse amplitudes and glaucoma progression.
Methods :
Patients were followed for five years in a prospective trial, having three visual field tests per year. At the end of the study PPG was performed on each patient over a range of induced intraocular pressures by ophthalmodynamometry. Pulse amplitudes at each point along the vessel were calculated by Fourier analysis. Maximum and mean pulse amplitudes along each hemivessel were calculated. Rates of visual field loss were calculated by both point wise linear regression on individual field loci to isolate maximum significant rates of loss or averaging sensitivity values across a hemifield and calculating linear regression slopes on the mean hemifield sensitivity corresponding to the respective hemi vessel. Linear mixed modelling was used with usual glaucomatous explanatory variables, including vessel pulse amplitudes and baseline mean hemifield sensitivity.
Results :
91 eyes from 55 patients had full data sets with good quality video recordings enabling PPG. Hemivein mean (p=0.0158) but not maximum (p=0.0708) pulse amplitudes were associated with maximum locus rates of visual field loss, finding that for each mean log unit pulse amplitude loss 0.28 dB/yr greater rates of locus field loss occurred. Hemivein mean (p=0.0001) pulse amplitude was associated with hemifield mean sensitivity loss rate, finding that for each log unit pulse amplitude loss 0.11dB/yr greater rate of field loss occurred. Hemiartery maximum (p=0.0451) and mean (p=0.0148) pulse amplitudes were associated with maximum locus rates of visual field loss, finding that for each log unit pulse amplitude loss, 0.39dB/yr greater rates of loss occurred. Hemiartery maximum (p=0.0108) but not mean (p=0.0573) pulse amplitude was associated with hemifield mean sensitivity loss rate, finding that for each log unit maximum pulse amplitude loss, 0.06dB/yr greater rate of field loss occurred.
Conclusions :
PPG calculated venous pulse amplitudes are associated with significantly altered rates of visual field loss in glaucoma. Unexpectedly, arterial pulse altitudes appear to have similar associations.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.