Enhanced Depth Imaging Optical Coherence Tomography in Uveitis: An Intravisit and Interobserver Reproducibility Study

Abstract

Purpose: To determine the intravisit and interobserver reproducibility of subfoveal choroidal thickness (SFCT) measurements in patients with noninfectious uveitis.

Design: Reliability analysis.

Methods: Two consecutive enhanced depth imaging optical coherence tomography (EDI-OCT) scans were obtained at a single clinic visit for 97 uveitic eyes from patients ≥16 years of age with noninfectious anterior (n = 10), intermediate (n = 11), posterior (n = 26), and panuveitis (n = 13) at the National Eye Institute. SFCT was manually measured by 2 ophthalmologists using manufacturer's software. Intravisit and interobserver reproducibility of SFCT measurements were assessed by using the Bland-Altman method to determine the estimate of bias (mean difference in SFCT measurements), 95% limits of agreement, and coefficients of repeatability. The reproducibility of these measurements was also compared between groups by anatomic location and clinical activity.

Results: Of 97 eyes, 65 (67.0%) were clinically quiet, 18 (18.6%) were minimally active, and 14 (14.4%) were active at the time the scans were obtained. Manual SFCT measurements were reproducible within 32.4 ± 3.8 μm between sessions for the same observer and 51.4 ± 8.5 μm between observers for the same session. Coefficients of repeatability did not differ significantly by anatomic location or disease activity.

Conclusions: Manual SFCT measurements obtained by EDI-OCT are reproducible in uveitis patients, with coefficients of repeatability that are nearly comparable to those published for normal eyes. This study provides guidance for using manual SFCT measurements in clinical practice, but further studies are still needed to determine their utility in clinical trials.

FIGURE 1

Measurement of subfoveal choroidal thickness by enhanced depth imaging optical coherence tomography in uveitis patients. Subfoveal choroidal thickness (double-headed arrow) is defined as the vertical distance from just outside the hyperreflective line corresponding to the outer border of the retinal pigment epithelium to the hyporeflective line corresponding to the inner scleral border. Bars represent 200 μm in length.

FIGURE 2

Representative scatterplots showing intraobserver, intravisit, and interobserver reproducibility of subfoveal choroidal thickness measurements using enhanced depth imaging optical coherence tomography for the right eye in uveitis patients. Mean subfoveal choroidal thickness (SFCT) is plotted against the difference in SFCT measurements at two different time points of measurement by a single observer (top left), between two sessions of enhanced depth imaging optical coherence tomography (EDI-OCT) for the same observer (top right and bottom left, respectively), and between two observers for the first EDI-OCT session (bottom right). The mean difference is denoted by a solid line, whereas the ideal mean difference of zero is shown by a dotted line. The upper and lower 95% limits of agreement are indicated by dashed lines, which correspond to two standard deviations (SD) from the mean difference. In all plots, the mean and SD of SFCT measurements appear relatively constant throughout the range of measurements.

FIGURE 2

Representative scatterplots showing intraobserver, intravisit, and interobserver reproducibility of subfoveal choroidal thickness measurements using enhanced depth imaging optical coherence tomography for the right eye in uveitis patients. Mean subfoveal choroidal thickness (SFCT) is plotted against the difference in SFCT measurements at two different time points of measurement by a single observer (top left), between two sessions of enhanced depth imaging optical coherence tomography (EDI-OCT) for the same observer (top right and bottom left, respectively), and between two observers for the first EDI-OCT session (bottom right). The mean difference is denoted by a solid line, whereas the ideal mean difference of zero is shown by a dotted line. The upper and lower 95% limits of agreement are indicated by dashed lines, which correspond to two standard deviations (SD) from the mean difference. In all plots, the mean and SD of SFCT measurements appear relatively constant throughout the range of measurements.

FIGURE 2

Representative scatterplots showing intraobserver, intravisit, and interobserver reproducibility of subfoveal choroidal thickness measurements using enhanced depth imaging optical coherence tomography for the right eye in uveitis patients. Mean subfoveal choroidal thickness (SFCT) is plotted against the difference in SFCT measurements at two different time points of measurement by a single observer (top left), between two sessions of enhanced depth imaging optical coherence tomography (EDI-OCT) for the same observer (top right and bottom left, respectively), and between two observers for the first EDI-OCT session (bottom right). The mean difference is denoted by a solid line, whereas the ideal mean difference of zero is shown by a dotted line. The upper and lower 95% limits of agreement are indicated by dashed lines, which correspond to two standard deviations (SD) from the mean difference. In all plots, the mean and SD of SFCT measurements appear relatively constant throughout the range of measurements.

FIGURE 2

Representative scatterplots showing intraobserver, intravisit, and interobserver reproducibility of subfoveal choroidal thickness measurements using enhanced depth imaging optical coherence tomography for the right eye in uveitis patients. Mean subfoveal choroidal thickness (SFCT) is plotted against the difference in SFCT measurements at two different time points of measurement by a single observer (top left), between two sessions of enhanced depth imaging optical coherence tomography (EDI-OCT) for the same observer (top right and bottom left, respectively), and between two observers for the first EDI-OCT session (bottom right). The mean difference is denoted by a solid line, whereas the ideal mean difference of zero is shown by a dotted line. The upper and lower 95% limits of agreement are indicated by dashed lines, which correspond to two standard deviations (SD) from the mean difference. In all plots, the mean and SD of SFCT measurements appear relatively constant throughout the range of measurements.

FIGURE 3

Boxplots showing mean subfoveal choroidal thickness measurements obtained by enhanced depth imaging optical coherence tomography for the right eye in uveitis patients, subcategorized by anatomical location and uveitic activity. Due to lower numbers of eyes in certain groups, measurements of eyes with anterior and intermediate uveitis and those of eyes with posterior and panuveitis are grouped together. Given similar representation of disease activity across all anatomic locations, measurements for eyes with any level of activity (i.e., minimally active, active) are also grouped together. (Left) Although no statistically significant difference is detected between groups by anatomical location of uveitis, a general trend of increasing subfoveal choroidal thickness (SFCT) towards the posterior segment is observed. (Right) Similarly, there is a non-significant trend of increasing SFCT with uveitic activity.

FIGURE 3

Boxplots showing mean subfoveal choroidal thickness measurements obtained by enhanced depth imaging optical coherence tomography for the right eye in uveitis patients, subcategorized by anatomical location and uveitic activity. Due to lower numbers of eyes in certain groups, measurements of eyes with anterior and intermediate uveitis and those of eyes with posterior and panuveitis are grouped together. Given similar representation of disease activity across all anatomic locations, measurements for eyes with any level of activity (i.e., minimally active, active) are also grouped together. (Left) Although no statistically significant difference is detected between groups by anatomical location of uveitis, a general trend of increasing subfoveal choroidal thickness (SFCT) towards the posterior segment is observed. (Right) Similarly, there is a non-significant trend of increasing SFCT with uveitic activity.