Visit COVID-19 resources

[Skip to Content]

BOSU report shows patients losing sight to follow-up appointment delays

8 February 2017

The Royal College of Ophthalmologists publishes a surveillance report of patients losing vision due to delays in treatment and follow-up appointments

The research, conducted through the British Ophthalmological Surveillance Unit (BOSU), found patients suffering permanent and severe visual loss due to health service initiated delays1.  The research involving all UK consultant ophthalmologists, showed that up to 22 patients per month may be losing vision by such delays. These patients are from a vulnerable social group with chronic conditions requiring long-term routine follow-up such as glaucoma, age related macular degeneration and diabetic retinopathy.

Early diagnosis and successful new treatments have increased the demands placed upon the Hospital Eye Service meaning that regular follow-up appointments within the clinically recommended time are not always accommodated demonstrating a lack of capacity and compromising patient safety.

The surveillance study through the BOSU2 was able to establish diagnosis, length of delay and cause of vision loss over a 12-month period, March 2015 – February 2016. Of the 169 patients reported of preventable loss of vision, 132 experienced permanent deterioration of vision along with 15 unplanned surgical procedures and six emergency hospital admissions. 42 patients were registered as Severely Sight Impaired or Sight Impaired.

The Royal College of Ophthalmologists (RCOphth) has previously raised concerns of patients losing vision due to hospital delays based upon evidence available in reports from the National Reporting and Learning System (NRLS)3.  Ophthalmology is a highly efficient specialty, but over the last decade, there has been nearly a 40% increase in eye out-patient clinic attendances across the UK and eye patients account for 8% of the 89 million out-patient visits in 2015-16 in England4.

Hospital eye services are required to meet the legal target of referral to treatment within an 18-week timeframe. The lack of safeguards, such as the absence of routine data available about delayed appointments for follow-up patients, means that hospital eye services are unable to quantify the extent of the problem or the harm coming to this, often vulnerable, patient group.

Professor Carrie MacEwen said, ‘The BOSU survey has validated what our members have been telling us for some time, which is concerns that patients are experiencing preventable sight loss due to delayed or lost follow-up appointments.’

The RCOphth are calling for NHS England to collect and report on the intended follow-up appointment date in hospital eye services, which will alert the ophthalmic teams of when a patient is not being seen within their clinically recommended time.

Professor MacEwen continued, ‘The benefits of the data item reporting will improve individual patient safety and reduce overall risks for all out-patients.  Being able to measure and identify shortfall in overall capacity will mean hospital eye services can more easily identify system improvements and stimulate discussion around new ways of providing care.’

The research report is available publically for a limited period up to 2 March 2017. 


  1. BOSU Study: Authors B Foot and C MacEwen ‘Surveillance of sight loss due to delay in ophthalmic treatment or review: frequency, cause and outcome’
  1. The British Ophthalmological Surveillance Unit operates a globally unique system for the epidemiological investigation rare ophthalmic diseases. It allows researchers to establish he incidence and clinical features of rare eye conditions of public health or scientific importance in the UK. BOSU is celebrating its 20th anniversary this year 1997-2017
  1. Available data relating to loss of vision due to delayed or lost appointments:

In 2009 the National Patient Safety Agency (NSPA) identified that it had received 44 reports of concerns about patient safety due to delays in appointments for glaucoma patients, of whom 13 went blind over a four-year period. This stimulated a Rapid Response Report

The National Reporting and Learning System (NRLS) receives confidential reports of patient safety incidents from healthcare staff across England and Wales. Clinicians and safety experts analyse these reports to identify risks to patients and opportunities to improve patient safety. The system is particularly helpful in identifying widespread safety issues from national trends which may not be apparent to individual units or practitioners from their experience of small numbers of local incidents.

A search was undertaken of NRLS incidents related to delayed ophthalmology appointments occurring in a two-year period between 2011 and 2013, of which most were return appointments at hospital eye departments with a smaller number of delays between primary care and the hospital service. The search identified nearly 500 incidents describing loss or deterioration of vision (130 severe harm and 350 moderate harm) from such delays, although from the incident report summary data it is difficult to determine how much sight loss was caused by delay and how much by deterioration of the underlying condition, and if the harm was permanent or reversible with treatment.