Acute corneal hydrops in keratoconus: a national prospective study of incidence and management

Purpose To determine incidence and management of acute corneal hydrops in the UK. Methods We used the BOSU report card system to survey cases of acute corneal hydrops in patients with keratoconus that occurred in the UK between November 2009 and December 2010. Ophthalmologists who reported a case were sent an initial questionnaire, with a follow-up questionnaire after 6 months. We collected information on the demographics, complications, changes in visual acuity, and management. The 2011 National Census was used as a source for population and ethnicity in the UK. Results There were 73 incident cases of acute corneal hydrops, with a response to the initial questionnaire for 64 (88%) patients and follow-up data at 6 months for 57 (78%) patients. For the 64 confirmed cases the median (interquartile range) age of onset was 31.9 (23.2, 41.3) years and 48 (75%) of the cases occurred in males. A total of 42 (66%) patients were white, 14 (22%) were South Asian, and 7 (11%) were black. The proportion of South Asian and black patients with acute corneal hydrops was significantly higher than in the general population (P<0.001). The minimum estimated annual incidence of acute corneal hydrops in patients with keratoconus was estimated to be 1.43 (1.10, 1.83) per 1000. At 6 months following acute corneal hydrops a decision to proceed with keratoplasty had been made for 12 (20.3%) patients. Conclusions This is the first population-based estimate of the incidence of acute corneal hydrops in keratoconus.