PurposeTo determine the frequency of patients suffering harm due to delay in ophthalmic care in the UK over a 12-month period.MethodsPatients with deterioration in vision in at least one eye of 3 lines of Snellen acuity or 15 letters on ETDRS chart or deterioration in visual field deviation of 3 decibels due to health service initiated delay in review or care were ascertained through the BOSU using prospective active surveillance involving all UK consultant ophthalmologists. Demographic details, diagnosis, cause and length of delay, and vision loss were then sought by questionnaire.Results238 cases reported between March 2015 and February 2016. 197/238 questionnaires were returned (83%). Twenty-eight reports were out of the study period or did not meet the case definition. Median age was 76 years (range: 1 to 98 years). Median delay was 22 weeks (range: 2 days to 5½ years). Seventy two per cent experienced permanent reduction in visual acuity, 23% permanent deterioration in visual field. Main diagnoses were Glaucoma 42%, Age-related Macular Degeneration (AMD) 23%, and Diabetic Retinopathy (DR) 16%. Eighteen patients were eligible for Severely Sight Impaired (SSI) or Sight Impaired (SI) registration. Main causes were delayed follow-up (76%), lost referral (7%), and delayed treatment (8%).ConclusionPatients are suffering preventable harm due to health service initiated delay leading to permanently reduced vision. This is occurring in patients of all ages, but most consistently in those with chronic conditions. Delayed follow-up or review is the cause in the majority of cases indicating a lack of capacity within the hospital eye service.