Fig 1.
The measurement of the Disc-center–Fovea Angle (DFA) using the Image J program.
‘a’ is a horizontal line drawn from the optic disc center. ‘b’ is a line drawn from the optic disc center to the fovea. ‘θ’ is the angle between lines a and b.
Table 1.
Measurements of the Disc-center–Fovea Angle (DFA) in the intermittent exotropia (IXT), unilateral Superior Oblique Palsy (SOP), and control groups using different nonmydriatic photographic methods: Conventional Fundus Photography (CFP), Wide-field Fundus Photography (WFP), and Optical Coherence Tomography (OCT).
Data are mean±standard-deviation values in degrees.
Fig 2.
DFA values for all 278 enrolled eyes measured using Conventional Fundus Photography (CFP), Wide-field Fundus Photography (WFP), and Optical Coherence Tomography (OCT).
The DFA measured using WFP was larger than when using the other two imaging modalities (p<0.001). The horizontal line indicates the median value, the boxes indicate the interquartile interval (25th and 75th percentiles), and the whiskers indicate the range.
Fig 3.
Bland-Altman plots of the agreement of the DFA between CFP and WFP and between CFP and OCT.
(A) Differences of the DFA between WFP and CFP plotted against the mean of the two measurements. The mean difference was 2.9°, and the 95% confidence interval (CI) (1.96 × standard deviation) was from –6.8° to +12.7°. (B) The mean difference of the DFA between OCT and CFP plotted against the mean of the two measurements. The mean difference was –0.1° and the 95% CI was from –1.9° to +1.8°. SD, standard deviation.
Fig 4.
Examples of differences in the DFA according to fundus photographic methods in the same patient.
The DFAs measured in the right and left eyes were 6.8° and 9.17°, respectively, for CFP (A), 9.51° and 13.16° for WFP (B), and 6.51° and 8.86° for OCT (C). The amount of ocular extorsion was measured as being larger for WFP.