Abstract
Purpose:
To validate a technique for obtaining specular microscopy (SM) readings in children under general anaesthesia (GA).
Methods:
This was a prospective, investigator-masked cohort study. Patients undergoing general anaesthesia for different ophthalmological surgical indications were prospectively recruited for this study. Specular microscopy images of the right eye of all subjects were obtained using the noncontact Konan specular microscope (Konan Medical, Inc. Hyogo, Japan) in the lateral decubitus position immediately after anaesthesia induction. A total of four good quality images were taken for each patient in the following manner: two consecutive images were first taken after approaching the patient’s head to the machine and without moving the patient head back to the supine position between acquisitions in order to assess intra-session variability. Another two images were then captured by placing the patient back and forth in the supine position, in order to assess inter-session variability. All images were analyzed by trained graders for endothelial cell counts using the centre method. Repeatability (intra-session variability) and reproducibility (inter-session variability) were evaluated using intraclass correlation coefficient (ICC) with a 95% confidence interval (CI).
Results:
Fifteen patients (15 eyes) were included in the study. The mean patient age was 5.7 ± 4 years (range: 1 to 14 years). The ICC’s for intra-session and inter-session variability were: 0.923 (CI 0.787 - 0.973, p = 0.001) and 0.841 (CI 0.590 - 0.943, p = 0.028), respectively. Measurement variability was further assessed by comparing randomly selected images; one from the first SM session and one out of the second and third measurement sessions. This yielded an ICC of 0.901 (CI 0.733 - 0.966, p = 0.003). The percentage variance was 2.35% and 3.42% for the intra-session and inter-session measurements, respectively.
Conclusions:
Specular microscopy measurements using a non-contact specular microscope under GA (non-fixating eye) are repeatable and reproducible and have similar variance as reported in the literature for awake adult patients. This is of great importance since our current understanding of the natural history of endothelial cell loss in early life is based on histological studies. We are now able to study paediatric endothelial cell natural history and response to intraocular surgery in-vivo.
Keywords: 481 cornea: endothelium •
479 cornea: clinical science •
550 imaging/image analysis: clinical