Abstract
Purpose::
The ocular pulse amplitude is an indirect indicator for the choroidal perfusion and reflects the ocular blood flow corresponding to the heart pulse as a function of time. The Ocular Hypertension Treatment Study demonstrated that visual field damage and IOP asymmetries are significantly related to primary open-angle glaucoma (POAG) onset. The aim of this study was to evaluate ocular pulse amplitude (OPA) using dynamic contour tonometer (DCT) in patients with asymmetric POAG and asymmetric IOP.
Methods::
The participants consisted of 48 patients (96 eyes) with asymmetric POAG. Three measurements of IOP and OPA were taken with DCT (Pascal dynamic contour tonometer; Swiss Microtechnology AG, Port, Switzerland), only measurements with quality 1 readings were used. The OPA data used in this study consist of the average of these 3 consecutive measurements. The diagnosis of asymmetry required a difference of glaucomatous visual field loss greater than 8 dB in the global index mean deviation (MD) and a difference of 5 mm Hg in IOP by Goldmann applanation tonometry (GAT) between the more affected and the contra-lateral eye of the same patient. Standard achromatic perimetry was performed by the Humphrey Field Analyser II 750 (Humphrey Systems Inc, Dublin, CA) using full-threshold 24-2 program. All participants underwent full ophthalmologic clinical assessment including ultrasonic pachymetry (Humprey ultrasonic pachometer, model 885; Humphrey System Inc, Dublin, CA). Only patients with a minimum best-corrected visual acuity of 20/25 or better and clear media were selected. Exclusion criteria were corneal diseases or scars, topical or systemic glaucomatous medications, and previous ocular surgery. Statistical package for social sciences (SPSS Inc., Chicago, IL) was used for statistical analysis.
Results::
The OPA values of the better eyes group (mean: 3.32 mm Hg, SD: +/- 1.14 mm Hg) were significantly lower (p < 0.05) than those obtained on worse eyes group (mean: 3.82 mm Hg, SD: +/- 1.27 mm Hg). No difference (p < 0.05) was found between the central corneal thickness values of the better eyes group (mean: 536.87 µm, SD: +/- 29.31 µm) and worse eyes group (mean: 534.00 µm, SD: +/- 29.61 µm).
Conclusions::
OPA was significantly higher in the worse eyes. According to this data there was no evidence that the OPA could play a protective role in asymmetric POAG.
Keywords: intraocular pressure