Evaluation of Parameters Affecting Measurement Quality of Dynamic Contour Tonometry

Objective: To evaluate factors affecting measurement quality of dynamic contour tonometry (DCT). Material and Methods: Three hundred patients took part in this prospective clinical study. For each patient, measurements for one eye were included in the study. Of the participants, 116 had ocular hypertension, 114 had glaucoma, and 70 had normal eyes. We used automatic refractokeratometry, ultrasonic pachimetry, Goldmann applanation tonometry, and DCT measurements to investigate the effects of age, corneal astigmatism, refractive error, central corneal thickness (CCT), intraocular pressures (IOP), and ocular pulse amplitude (OPA) on DCT measurement quality (Q). Logistic regression analysis was used for statistical analysis. Results: For 159 patients, the DCT Q score was 1 (group 1). For the remaining 141 patients, the Q score was 2&ndash;3 (group 2). The following values were determined for the two groups, respectively: mean age 58.9&plusmn;9.9 and 61.4&plusmn;10.6; mean corneal astigmatisms &minus;0.78&plusmn;0.67 and &minus;0.92&plusmn;0.77 diopter; mean spherical equivalents 0.33&plusmn;1.87 and &minus;0.01&plusmn;2.02 diopter; mean CCT 547.0&plusmn;35.2 and 549&plusmn;38.7 &mu;m. Measurements with DCT provided mean IOPs of 18.5&plusmn;3.70 and 21.27&plusmn;6.19 mm Hg and mean OPA 3.5&plusmn;1.4 and 3.2&plusmn;1.2 mm Hg. By logistic regression analysis, we determined that the parameters affecting measurement quality were age, DCT measurement level, and OPA (p=0.015, p=0.000, and p=0.000, respectively). Conclusion: High IOP values, advanced age, and low OPA values can lead to decreased DCT measurement quality.

Keywords:

Dynamic contour tonometry ocular rigidity, Q score,

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