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Abstract #12026 Published in IGR 7-1
Central corneal thickness: will one measurement suffice?
Wickham L; Edmunds B; Murdoch IEOphthalmology 2005; 112: 225-228
OBJECTIVE: To evaluate the measurement of central corneal thickness (CCT) in a cohort of glaucoma patients over a 3-month period. Measurements were then applied to the criteria described in the Ocular Hypertension Treatment Study (OHTS). DESIGN: Cohort study. PARTICIPANTS AND METHODS: Fifty-one patients were recruited from a glaucoma clinic at Moorfields Eye Hospital. Central corneal thickness was measured using an ultrasonic handheld pachymeter by a trained observer. Patients' CCTs were measured at 2 consecutive clinic visits. MAIN OUTCOME MEASURE: Mean central corneal thickness. RESULTS: The readings showed clear fluctuation over the 3-month period, with a mean difference in corneal thickness of 9.6 ± 26.9 μm in the right eye and 19.0±29.2 μm in the left eye. In addition, there was a systematic bias towards increased corneal thickness being recorded at the second reading in both eyes. This reached statistical significance in both the right eye (P = 0.02) and the left eye (P = 0.0003). The criteria used to categorize the risk of patients developing glaucoma in the OHTS were then applied to these results. On the basis of the second reading, 32% of eyes required recategorization in both the right and left eyes. CONCLUSIONS: Measurements of CCT taken within a clinical setting by a trained observer may show significant variability. For CCT to become a valuable addition to the assessment of glaucoma suspects, more than one reading may be required. Failure to do so may result in misclassification and, thus, an inaccurate assignment of risk.
Dr. L. Wickham, Moorfields Eye Hospital, London, United Kingdom. louisa.w@tiscali.co.uk
Classification:
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)