Purpose:.To study the clinical manifestations and the diag-nostic and differential diagnostic characteristics of acute idio-pathic blind spot enlargement syndrome (AIBSES).Methods:.Six patients diagnosed with AIBSES underwent complete eye examinations including fundus photography, fundus fluorescein angiography(FFA), indocyanine green an-giography (ICGA), optical coherence tomography (OCT), electroretinogram (ERG), and visual field examinations.Results: All patients had enlarged blind spots of variable sizes and densities..Three eyes had mild swelling of the optic disc and one eye had peripapillary scarring that corresponded to the permanent field defect. Two patients who underwent FFA had fluorescein leakage of blood vessels around the optic disc and ICGA highlighted diffuse, small hypofluorescent spots scatter-ing throughout the posterior pole..OCT showed that the inner and outer segment (IS / OS).line were absent in five patients and the middle cone outer segment tip line was absent in the nasal macular area in one eye.Conclusion: AIBSES is a rare outer retinopathy. Visual field examination and OCT are the most important means of detec-tion. ICGA and FAF can determine the range of lesions earli-er, and the progress of the disease should be taken into ac-count when making a diagnosis.(Eye Science 2014; 29:143-150)