Comparing Ocular Coherence Tomography Relational Thickness Metrics of Normal and Suspect Eyes
To compare Spectral-Domain Ocular Coherence Tomography (SD-OCT, Optovue, Inc.) superior-inferior (S-I) and central corneal thickness minus thinnest point (CCT – TP) values between normal and suspicious eyes to determine if these thickness variables are helpful in identifying increased ectasia susceptibility for refractive surgery screening.
Retrospective, consecutive series of 304 eyes from 152 patients presenting for refractive surgical evaluation were evaluated with SD-OCT. The eyes were then divided into two groups based on the ectasia risk score screening system. 100 eyes were labeled normal and 204 eyes were labeled suspicious based on an ectasia risk score ≥ 3. The SD-OCT S-I and CCT-TP values were averaged for each group and compared between groups. A two-tailed, Student’s t-test was used for statistical comparison.
The average S-I value of normal eyes was 10.27 ± 15.49 and the average S-I value of suspicious eyes was 26.64 ± 17.01 (p < 0.0001). The average CCT-TP value of normal eyes was 7.76 ± 4.91 and the average CCT-TP value of suspicious eyes was 4.76 ± 36.8 (p = 0.25).
The S-I thickness metric may be beneficial in identifying asymmetric thinning in refractive surgical screening to detect increased ectasia susceptibility but the CCT-TP value was not useful.