Relationship of inferior oblique overaction to macular and subfoveal choroidal thickness

PURPOSE To evaluate the macular and subfoveal choroidal thickness of eyes with inferior oblique muscle overaction (IOOA) using enhanced depth imaging spectral domain optical coherence tomography (EDT SD-OCT). METHODS The measurements of macular and subfoveal choroidal thickness obtained by EDI SD-OCT of patients with IOOA (24 patients) were compared with those of age- and sex-matched controls (25 subjects). RESULTS There were no morphological abnormalities of the macula in patients with IOOA or in control subjects. There were no statistically significant differences in macular and subfoveal choroidal thickness between the eyes with IOOA and the eyes of the control subjects (P > 0.05). When the patients with IOOA were assigned to two distinct groups according to the degree of IOOA, the macular thickness did not differ between groups (P = 0.66), whereas subfoveal choroidal thickness measures were significantly lower in eyes with severe IOOA compared to eyes of the controls (P = 0.01). CONCLUSIONS IOOA has no effect on the morphology and the thickness of the macula. Severe IOOA seems to be related to thinning of subfoveal choroid due to possible external mechanical effect.