BackgroundStevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare and extremely serious drug-induced dermatological disorders. The ocular surface condition at the early stage has been little studied and should contribute to novel perspectives in early and effective topical therapy of these diseases. The objectives of the study were to evaluate the acute phase of ocular surface involvement and histopathologic changes in patients with acute SJS/TEN.MethodsTen patients with acute phase of SJS/TEN onset and eleven age- and sex-matched healthy volunteers were recruited. Ocular surface symptoms and signs, conjunctival impression cytology, and tear multi-cytokine were assessed.ResultsOcular surface objective signs were normal at the acute stage of SJS/TEN, while most patients have abnormal ocular surface subjective symptoms and meibomian gland secretion. Conjunctival impression cytology showed a significant decrease in goblet cell density and severe ocular surface squamous metaplasia in acute SJS/TEN patients. Tear multi-cytokine analysis showed all 21 pro- and anti-inflammatory cytokines all sharply elevated. Goblet cell density was significantly negatively correlated with tear C-X3-C motif chemokine ligand 1 (CX3CL1) and interleukin 13.ConclusionsSevere pathologic squamous metaplasia and inflammation onset in the ocular surface at the acute stage of the SJS/TEN, even if the ocular surface condition seemed basically normal with adequate systemic immunosuppressant and general supportive treatment. Early topical anti-inflammatory therapy should be carried out actively.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12886-023-03052-7.