Comparion of Central Corneal Thickne uing Anterior egment Optical Coherence Tomography v Ultraound Pachymetry Original Reearch Article

Purpoe To determine if there i a ytematic difference in central corneal thickne (CCT) meaured uing anterior egment optical coherence tomography (A-OCT) a compared with ultraound pachymetry. Deign Propective obervational tudy. Method Conecutive ubject with clinically normal cornea underwent CCT meaurement by both ultraound and A-OCT while participating in a population-baed tudy in Ghana, Wet Africa. One eye of each ubject wa randomly elected for analyi. Two meaurement were taken and averaged. Agreement and interoberver variability were alo analyzed. Reult One hundred and fifty-five ubject of African ethnicity and average age 57 year (tandard deviation [D] 12; range, 40 to 98 year) were included. Meaurement by A-OCT and U were taken a mean of 15 day (maximum, ix week) apart. The mean (D) [range] U CCT wa 525.3 μm (33.5) [422, 653] and 499.0 μm (32.0) [428, 613] with A-OCT. Meaurement by the two modalitie were trongly correlated (r2 = 0.82; P < .001), and a ignificant difference wa oberved between mean U and A-OCT CCT (D) [range] of 26.3 μm (14.2) [−63, 12] (P < .001). The width of the limit of agreement wa 28 μm, about 6% of the average pachymetry reading. In 50 eye randomly remeaured with OCT by a econd oberver, the intracla correlation coefficient wa 0.91. There wa a mall but ignificant ytematic difference between oberver (mean 6.9 μm, D 10.9 μm), or 1.4% (P < .001), increaing the difference noted above. Concluion There i a reproducible ytematic difference between CCT meaurement taken with ultraound and OCT. It i important to note in clinical practice, that meaurement acquired by thee two modalitie are not directly interchangeable.