Author: Lydia Schwer (Germany)
Co-authors: Ahmend Almarzooqi, Katharina Blobner, Daniel Zapp, Katharina Kirchmair, Chris P. Lohmann, Stephen B. Kaye
Purpose
To assess repeatability and reproducibility of measuring the minimum linear diameter (MLD) of macular holes (MH) using horizontal linear and radial scan modes in optical coherence tomography (OCT).
Setting/Venue
Department of Ophthalmology, Hospital Rechts der Isar, Technical University of Munich (TUM), Germany
Methods
Patients with concurrent sets of radial and horizontal linear OCT volume scans were included. The MLD was measured twice in both scan modes by six raters of 3 different experience levels (groups). Outcome measures were the reliability and repeatability of MLD measurements.
Results
Fifty patients were included. Mean MLD was 317.21(±170.63) µm in the horizontal linear and 364.52 (±161.71) µm in the radial mode, a difference of 47.31 (±26.48) µm (p<0.001).The intra-group coefficients of repeatability (CR) for the horizontal linear mode were 23µm, 33µm and 45µm, and for the radial mode 25µm, 44µm and 57µm for group 1, 2 and 3, respectively. The inter-group CR, taking group 1 as reference standard for groups 2 and 3, were 74µm and 71µm for the linear mode, and 62µm and 78µm for the radial mode. For both the horizontal and the radial mode, there were no significant differences in MLD measurements, either within raters (p≥0.22 and p≥0.16) or groups (p≥0.91 and p≥0.31), or between raters (p=0.98 and p=0.97) and groups (p=0.76 and p=0.81). For both the linear and the radial mode, however, there was a significant increase in variability from group 1 to group 2 (p<0.01, p<0.01), group 1 to group 3 (p<0.01, p<0.01) and from group 2 to group 3 (p=0.015, p=0.003). In the radial scan mode, the MLD was identified within 15° of the horizontal meridian in 27% and within 15° of the vertical meridian in 26.7%, with the remainder (46.3%) in oblique meridians
Conlusions
The radial mode provides comparably good repeatability and reproducibility to the horizontal mode for measurement of MLD size of MH. The variability of measurements decreases in both modes as the experience of the raters increases. In a majority of cases the MLD does not lie in the horizontal meridian and would be underestimated using a horizontal OCT mode.
Financial Disclosure
no
Comments
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