Abstract
Purpose:
Full thickness macula hole (FTMH) size on optical coherence tomography (OCT) is commonly used for classification, to plan management and to offer prognoses of outcome. However, limited evidence exists regarding observer agreement on hole size measurement.
Methods:
Sixty-two OCT scans (Topcon 3D OCT 2000) of sixty patients with FTMH were reviewed by three ophthalmologists on two occasions separated by at least two weeks. The three observers were experienced in interpreting OCT images and used an agreed method of measurement. Base diameter (BD), minimum linear diameter (MLD) and macula hole inner opening (MHIO) were measured using the calliper function of the imaging software. Pearson’s Correlation Coefficient and Bland-Altman 95% limit of agreement (LA) were calculated.
Results:
There was a statistically significant correlation between all measurements for the three parameters: 0.82 to 0.98 (p≤0.0001). However, the 95% LA for BD were: -178 to +192µm, -146 to +147µm, -180 to +202µm (Inter Observer) and -158 to +140µm, -89 to +70µm, -153 to +87µm (Intra Observer); for MLD were: -93 to +81µm, -88 to +58µm, -139 to +95µm (Inter observer) and -126 to +137µm, -66 to +83µm, -47 to +83µm (Intra Observer); and for MHIO were -165 to +137µm, -193 to +91µm, -251 to +118µm (Inter observer) and -273 to +209µm, -187 to +86µm, -96 to 85µm (Intra observer).
Conclusions:
Despite correlation, there is substantial inter and intra observer variability in the measurement of macula hole size. We believe that caution should be exercised when using these parameters for classification and when drawing prognostic conclusions upon which to base management.
Keywords: 586 macular holes