The aim of this study is to investigate early findings of the choroidal effusion induced by topiramate use which is thought to be responsible for bilateral acute angle closure glaucoma. Enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT) recordings of 34 patients who has been used topiramate for the prophylaxis of migraines, before and after 2 weeks of drug use were retrospectively investigated. Alterations in subfoveal choroidal layer thicknesses and peripapillary retinal nerve fiber layer (RNFL) thickness were measured manually by two masked observers. The mean measurements of subfoveal choroidal layer thickness were 315.67 +/- 80.98 mu m before use of the drug and 314.89 +/- 76.40 mu m in 2nd week of drug use. However, this slight decrease was not statistically significant. The mean peripapillary RNFL thickness was 104.47 +/- 10.48 mu m before use of the drug, and significant thinning was found only in the temporal quadrant during follow-up after use of the drug (p=0.008). No subclinical subfoveal choroidal effusions were encountered using EDI SD-OCT in patients after 2 weeks of topiramate use. Further studies are needed to find out the cause of bilateral ciliochoroidal effusion related with topiramate use.