purpose: to compare clinical characteristics and surgical out comes between keratoconus cases with and without acute hydrops (ah). methods: all keratoconus cases followed up at the hospital universitário ant？nio pedro - uff and at clinica oftamológica souza pena between 1982 and 2000 were reviewed. main analyzed outcome parameters were: visual acuity, follow-up time since diagnosis, type of visual correction, morphological and keratometric classification, and surgical results. results: the overall acute hydrops incidence was 5.8%. gender, keratoconus family history, atopy did not differ significantly between the two groups. among acute hydrops cases, 72.7% were classified as peripheral cones, against 21.4% of the control cases (p < 0.05). overall, 19% of the patients needed penetrating keratoplasty (pk). out of 1062 eyes that did not develop acute hydrops, 8.4% underwent pk, compared to 88.4 % of the acute hydrops eyes (p < 0.05). surgical outcomes showed no significant difference between the two groups. conclusion: peripheral cones were more frequently related to acute hydrops, and consequently, to pk. keratoconus surgical treatment results were similar in cases with and without acute hydrops.