Abstract
Abstract: :
Purpose: To evaluate the effect of central corneal thickness (CCT) determination upon the clinical management of patients with diagnoses of glaucoma and glaucoma suspect. Methods: A cross-sectional retrospective study was performed on 188 consecutive patients seen at an academic medical center glaucoma practice. Three consecutive ultrasound pachymetry measurements of CCT were obtained from each patient’s right eye and an average value computed. Corresponding Goldmann applanation tonometry measurements were also obtained. Intraocular pressure (IOP) measurements were then adjusted for CCT using .545 mm as the "standard" or "reference" CCT value. The IOPs were corrected using both linear and exponential algorithms. Based on literature review, the linear correction scale added or subtracted 2 mmHg for every .05 mm difference in CCT from the reference value of .545 mm. In addition, a log-linear formula (Orssengo Pye algorithm) was employed. Clinically significant outcomes were defined as an adjustment of IOP between 1.5 and 3 mmHg and outcomes significant results were defined as an adjustment of greater than or equal to 3 mmHg. Changes in therapy such as the addition/subtraction of drops and addition/cancellation of laser therapy or surgery were then noted for those individuals with clinically or outcomes significant changes. Results: Using the linear correction scale 82 out of the 188 eyes, (44%) had either a clinically significant or an outcomes significant adjustment made to their IOP measurements: 63 (34%) of the patients had a clinically significant adjustment of their IOP measurements and 19 (10%) of them had an outcomes significant IOP adjustment. Of the total patients, 15 (8%) had a change in drop therapy, 3 (2%) had the addition/subtraction of laser therapy, and 5 (3%) had a change in the decision regarding glaucoma surgery. Using the exponential correction scale, similar percentages were obtained. Of the 188 eyes, 90 (48%) had either a clinically significant or an outcomes significant adjustment of their IOP measurements. 68 (36%) of the patients had a clinically significant adjustment, while 22 (12%) of them had an outcomes significant IOP adjustment. Of the total patients, 19 (10%) had a change in their drop regimen, 4 (2%) had deferment of laser treatment, and 5 (3%) did not require additional glaucoma surgery. Conclusions: Pachymetry measured-CCT has a significant impact upon the clinical management of patients with diagnoses of glaucoma and glaucoma suspect.
Keywords: cornea: clinical science • clinical (human) or epidemiologic studies: sys • intraocular pressure