![]() ![]() This cross-sectional study was composed of 35 patients (70 eyes) who had been previously diagnosed with glaucoma. The aim of the present study was therefore to evaluate the accuracy of the CCT measurements performed by three different observers using both OCT and USP in patients diagnosed with glaucoma. The only confirming study regarding CCT measurements with OCT in glaucomatous eyes was that of Garcia-Median et al. ![]() Previous studies were performed in normal eyes or eyes suffering from keratoconus. However, it is not known how repeatable and stable the measurements are. OCT is now widely used at ophthalmology departments, mostly for measuring thickness in the retina but the OCT instrument can be used for measuring thicknesses in the cornea and the nerve fiber layer. One type is the optical coherence tomography (OCT) instrument. Newer instruments are currently available that have the advantage of being the non-contact type. ![]() Moreover, this instrument is a contact type pachymeter, requiring aseptic precautions and anesthetizing the cornea, and the further possibility of injury to the cornea. Before USP measurements, topical anesthesia must be instilled and this could induce bias in the measurements. Its accuracy depends on the placement of the probe on the cornea, and the perpendicularity of the probe in relation to the cornea is often difficult to ascertain. However, ultrasound pachymetry (USP) has several possible sources of error. Ĭurrently, ultrasound corneal thickness measurement (pachymetry) is the most frequently used clinical technique and the gold standard to assess CCT. According to the results of the Ocular Hypertension Treatment Study, an individual with a CCT measuring 40 μm thinner than the average has a 71 % greater risk of developing glaucoma. Moreover, CCT is the most predictive factor for progression of ocular hypertension to glaucoma. Most studies have found that increased or decreased CCT could lead to overestimating or underestimating the true intraocular pressure (IOP). OCT might be used as an alternative method for pachymetry in glaucoma patients.Ĭentral corneal thickness (CCT) measurement has become an important test in the diagnosis and management of glaucoma. ConclusionsĪgreement among the three observers using OCT or USP for pachymetry measurements was good. The intraclass correlation coefficients were, for OCT, 0.99, and for USP, 0.97 (CI: 0.95–0.98). The differences between OCT and USP were not significant ( t-test, p = 0.32). The average age was 74 ± standard deviation (SD) 10.88, the average pachymetry value with OCT was 536 ± 29 μm, and the average pachymetry with USP was 532 ± 32 μm. Seventy eyes of 35 patients were included. ![]() The patients CCTs were measured with OCT and USP by three different examiners. Glaucoma was defined as patients who had at least two repeatable Humphrey visual fields showing glaucoma damage using the software 24–2, and with the optic nerve showing typical glaucoma damage. Patients who had been previously diagnosed with glaucoma participated in this cross-sectional study. The aim of the present study was therefore to evaluate the accuracy of the CCT measurements performed by three different observers, both with the OCT and ultrasound pachymetry (USP), in patients suffering from glaucoma. Newer instruments are currently available including the optical coherence tomography (OCT) instrument. Currently, ultrasound corneal thickness measurement (pachymetry) is the most frequently used clinical technique and the gold standard to assess CCT. Central corneal thickness (CCT) measurement has become an important test in the diagnosis and management of glaucoma. ![]()
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