Comparison of Ocular Pulse Amplitude Measured Using Dynamic Contour Tonometry and Ocular Blood Flow Analyzer

PURPOSE: To compare ocular pulse amplitude (OPA) measured using dynamic contour tonometry (DCT) and ocular blood flow analyzer (BFA). METHODS: Thirty-five eyes of 35 patients were enrolled in this cross-sectional and retrospective study. OPA was measured using DCT. Pulse amplitude (PA) and pulsatile ocular blood flow were measured using BFA. RESULTS: OPA measured using DCT (2.79 +/- 0.89 mm Hg) was not significantly different from PA measured with BFA (3.02 +/- 0.90 mm Hg; p = 0.082) and both were significantly correlated (r = 0.663, p < 0.001). Mean difference +/- limit of agreement was -0.22 +/- 1.44 mm Hg between OPA and PA. OPA correlated significantly with intraocular pressure (IOP) measured using Goldmann applanation tonometry (r = 0.330, p = 0.047) but not PA (r = 0.057, p = 0.745). Both PA and OPA did not show significant correlation with the spherical equivalent of refractive error and central corneal thickness. CONCLUSIONS: Although both OPA and PA measure IOP fluctuation and are not significantly different, they showed different relationships with IOP.

Positional Change of Intraocular Pressure and Its Relationship to Ocular Pulse Amplitude

PURPOSE: To investigate the postural change of intraocular pressure (IOP) from sitting to supine position and determine the relationship to other ocular parameters including ocular pulse amplitude (OPA) in glaucoma suspect and open angle glaucoma patients. METHODS: The present study included 46 eyes of 46 patients. First, we measured IOP and OPA using Goldmann applanation tonometer (GAT), Pascal dynamic contour tonometer and TonoPen(R). Using TonoPen(R), the IOP was measured immediately after the subjects were placed in a supine position and 10 minutes and 30 minutes thereafter. We also investigated the correlation between positional change of IOP and axial length (AL), refractive error (RE), and OPA. RESULTS: IOPs of patients in a sitting position measured with GAT and TonoPen(R) were 15.3 +/- 3.3 mm Hg and 16.6 +/- 2.9 mm Hg, respectively, and OPA was 2.57 +/- 0.89 mm Hg. IOPs measured with TonoPen(R) were 17.6 +/- 2.9 mm Hg immediately after position change, 18.2 +/- 3.7 mm Hg after 10 minutes and 17.5 +/- 2.7 mm Hg after 30 minutes. Each IOP change was statistically significant and the largest change was after 10 minutes. Changes of IOP after 10 minutes were positively correlated with OPA (R = 0.340) and RE (R = 0.330) and negatively correlated with AL (R = -0.410). CONCLUSIONS: When placed in a supine position, the IOP of patients increased and then decreased over time. Positional IOP change was influenced by AL and OPA and variable hemodynamic factors and apparently influenced OPA and ocular perfusion pressure.

Repeatability of Peripapillary Atrophy Parameters Measured Using Optic Disc Stereophotography and Evaluation of Its Diagnostic Ability

PURPOSE: To investigate the measurement repeatability of peripapillary atrophy (PPA) parameters obtained by optic disc stereophotography (ODP) and evaluate the usefulness of PPA parameters to differentiate open-angle glaucoma (OAG) from normal eyes in patients with PPA. METHODS: Sixty-five eyes of 65 patients with PPA were examined. Disc area, cup area, rim area, vertical cup to disc (CD) ratio, CD area ratio, PPA area, zone beta (beta) area and zone alpha (alpha) area were obtained by ODP using intrinsic algorithms. The area under the receivers operating characteristic (AUROC) curves was used to compare the PPA parameters with that of the disc parameters to differentiate OAG from normal eyes. Two examiners analyzed PPA parameters to confirm reproducibility and repeatability of ODP. RESULTS: Vertical CD ratio (VCD), area CD ratio, zone beta area, zone beta area per PPA area, zone beta area per disc area and axial length were significantly larger in OAG patients (p 0.997). CONCLUSIONS: The PPA measurement obtained by ODP has good reproducibility and consistency and can be a useful tool in monitoring PPA changes in glaucoma patients.

Comparison of Dorzolamide-Timolol Fixed Combination and Latanoprost, Effects on Intraocular Pressure and Ocular Pulse Amplitude

PURPOSE: To compare dorzolamide-timolol fixed combination (DTFC) and latanoprost with regard to their effects on intraocular pressure (IOP) and ocular pulse amplitude (OPA). METHODS: Sixty eyes of 60 patients with open angle glaucoma or glaucoma suspect were included in the present study. Patients were divided into 2 groups, DTFC-treated (n = 30) and latanoprost-treated (n = 30). IOP and OPA were measured with dynamic contour tonometer (DCT) and Goldmann applanation tonometer (GAT), before and at least 1 month after treatment. RESULTS: GAT IOP, DCT IOP and OPA decreased by 2.25 +/- 2.23 mm Hg, 1.97 +/- 2.06 mm Hg, and 0.14 +/- 0.88 mm Hg, respectively in the DTFC-treated group. In the latanoprost-treated group, GAT IOP, DCT IOP and OPA was reduced by 2.74 +/- 2.96 mm Hg, 2.06 +/- 3.50 mm Hg, and 0.69 +/- 1.07 mm Hg, respectively. There was no significant difference (p = 0.311) in the decline of IOP between the 2 groups, but OPA of the DTFC-treated group decreased less than the latanoprost-treated group (p = 0.032). CONCLUSIONS: No significant differences were observed in the short-term decline of IOP between the 2 medications. However, the influence of DTFC on OPA appeared negligible in the latanoprost-treated group.

The Ability of Disc-to-Fovea Distance to Disc-Diameter Ratio to Estimate Optic Disc Size

PURPOSE: To investigate the usefulness of the measurement of disc-to-fovea distance to disc-diameter ratio (DF/DD ratio) in detecting large and small discs. METHODS: A total of 300 randomly selected subjects were included in the present study. All patients underwent stereoscopic disc photography and DF/DD ratio, which is the shortest distance between disc margin and fovea divided by mean disc diameter was determined by planimetry. The diagnostic accuracy of DF/DD ratio was evaluated using areas under the receiver operating characteristics curves (AUCs), sensitivity, and specificity. RESULTS: No significant differences in disc-to-fovea distance were observed among small and large disc groups. The DF/DD ratio was significantly lower in subjects with large discs (1.74 +/- 0.27) compared with subjects with small discs (2.70 +/- 0.15). AUCs of the DF/DD ratio were 0.942 and 0.947 in detecting large and small discs, respectively. In detecting disc size by a fixed DF/DD ratio of 2.0, sensitivity was 100% for both large and small discs, and specificity was 70.1% and 40.9% for the large and small discs, respectively. CONCLUSIONS: The DF/DD ratio may be a simple and useful clinical aid in detecting large and small discs. The 2.0 fixed DF/DD ratio, showed 100% sensitivity in detecting both large and small discs, although medium discs may be misdiagnosed as small discs more often than as large discs.

The Effect of Cataract Surgery on Ocular Pulse Amplitude

PURPOSE: To investigate the change of intraocular pressure (IOP) and ocular pulse amplitude (OPA) measured by dynamic contour tonometry (DCT) after cataract surgery and to identify the influencing factors related with OPA change after cataract extraction. METHODS: The present study included 32 patients who underwent unilateral cataract surgery and the non-operated fellow eyes were used as control. IOP was measured by Goldman applanation tonometry (GAT) and Pascal DCT preoperatively, and 3 months postoperatively. Additionally, OPA was measured by Pascal DCT preoperatively, and 3 months postoperatively. Axial length (AL), anterior chamber depth (ACD), and central corneal thickness (CCT) were measured preoperatively. RESULTS: After cataract surgery, IOP by GAT, IOP by DCT, and OPA decreased significantly with a mean decrement of 1.3 mm Hg, 1.6 mm Hg, and 0.5 mm Hg, respectively (p 0.05) postoperatively. The most important factor influencing the decrement of IOP by GAT, IOP by DCT, and OPA after cataract surgery was the preoperative level of their measurements (r = 0.382, p < 0.05 in GAT, r = 0.807, p < 0.001 in DCT, r = 0.627, p < 0.001 in OPA). In addition, the OPA decrement after cataract surgery was significantly correlated with age (r = -0.370, p = 0.037), and was not correlated with AL, ACD, and CCT. CONCLUSIONS: Both IOP and OPA decreased after cataract surgery, which appears to influence the relationship between IOP and OPA. The correlation between OPA decrement and age may be related to increased ocular rigidity with aging.

The Effect of Cataract Surgery on Ocular Pulse Amplitude

PURPOSE: To investigate the change of intraocular pressure (IOP) and ocular pulse amplitude (OPA) measured by dynamic contour tonometry (DCT) after cataract surgery and to identify the influencing factors related with OPA change after cataract extraction. METHODS: The present study included 32 patients who underwent unilateral cataract surgery and the non-operated fellow eyes were used as control. IOP was measured by Goldman applanation tonometry (GAT) and Pascal DCT preoperatively, and 3 months postoperatively. Additionally, OPA was measured by Pascal DCT preoperatively, and 3 months postoperatively. Axial length (AL), anterior chamber depth (ACD), and central corneal thickness (CCT) were measured preoperatively. RESULTS: After cataract surgery, IOP by GAT, IOP by DCT, and OPA decreased significantly with a mean decrement of 1.3 mm Hg, 1.6 mm Hg, and 0.5 mm Hg, respectively (p 0.05) postoperatively. The most important factor influencing the decrement of IOP by GAT, IOP by DCT, and OPA after cataract surgery was the preoperative level of their measurements (r = 0.382, p < 0.05 in GAT, r = 0.807, p < 0.001 in DCT, r = 0.627, p < 0.001 in OPA). In addition, the OPA decrement after cataract surgery was significantly correlated with age (r = -0.370, p = 0.037), and was not correlated with AL, ACD, and CCT. CONCLUSIONS: Both IOP and OPA decreased after cataract surgery, which appears to influence the relationship between IOP and OPA. The correlation between OPA decrement and age may be related to increased ocular rigidity with aging.