The authors reviewed 93 consecutive cases with optic disc swelling (ODS) with the purpose of comparing the clinical manifestations and prognosis between cases. The aim was to understand the differences in frequency and clinical features of ODS, relating these to causes and patient demographics to help clinicians to determine the cause and predict outcomes for patients presenting in clinic. This is important because, although differential diagnosis of ODS includes various diseases, determination of the exact cause is critical due to the many possible vision or life threatening diseases that may be present. In this case review, among unilateral ODS patients ≥50 years old and without pain, anterior ischaemic optic neuropathy accounted for 87.5%. Furthermore, papilloedema (PE) presented unilateral ODS with an atrophic or hypoplastic disc in the opposite eye. In addition, despite no differences for age and initial visual acuity between PE and pseudopapilloedema, the two main causes of bilateral ODS, some PE patients showed poor visual prognosis. The authors conclude that there are characteristic clinical features related to the causes of unilateral and bilateral ODS and knowledge of their differences can help clinicians to determine cause and predict prognosis.