Initially, the first 100 patients undergoing cataract surgery between May and July 2020 under five senior surgeons were studied in detail. In order to provide accurate data on the time spent in the department for consultant-delivered routine cataract surgery, patients undergoing combined procedures (e.g., phaco + istents, oculoplastics) and all patients on such mixed lists, and those undertaken by trainee surgeons were excluded.

All patients were contacted via telephone pre-operatively to discuss the risks of COVID-19 by a consultant surgeon. At the time of booking, all patients were asked COVID-19 screening questions. All patients had initially completed stage one of the consent process with a doctor at the clinic/listing stage.

All staff were required to have their temperature taken daily and to wear surgical masks at all times while in the department (prior to UK government directive mandating universal wearing).

An outpatient style flow through the department was created to ensure patients were in the hospital for the shortest possible time with staggered arrival times. In line with NHS England directives [4], as the patients were all treated as outpatients, patients were not required to undergo a two-week isolation period prior to surgery, nor did they undergo PCR swabbing for SARS-Cov2. On arrival, they had their temperature checked and COVID-19 screening questions were again asked. Once they had been booked into the department and initial checks were completed, a Mydriasert mydriatic device (Thea Pharmaceuticals) was inserted into the inferior fornix of the relevant eye(s) to be operated and the patient was asked to wait outside the department, often in their car, until pupil dilation was complete. Mydriasert is an insoluble ophthalmic insert for mydriasis that gradually releases its active ingredients of 0.25 mg tropicamide and 5.4 mg phenylephrine over up to a two-hour period, however, sufficient dilatation is typically achieved in 40 min [7]. The patients were then paged using a cleanable series of remote buzzer/pager devices to come back to the department to complete consent with the surgeon and then taken directly into surgery. This eliminated the use of a waiting area, as well as reducing time spent in the department.

The Toul Meditech Operio Mobile medical device was used in the clean room in order to filter the air and provide a sterile area within which to carry out cataract surgery, in line with Royal College of Ophthalmologists guidelines [8]. A representative from Toul advised on the positioning of the device. The risk of infection was further reduced by ensuring the door was kept closed for the duration of the surgery and that there was minimal talking while operating, with all staff wearing masks. Instruments were laid out in the clean room under the Toul Meditech Operio Mobile filter rather than in a separate room. The number of people in the room was minimised using one surgeon, one surgical assistant, one scrub nurse and usually one theatre support worker. Phacoemulsification was carried out using the Bausch & Lomb Stellaris, using 2.2 mm and 2.85 mm incisions, with copious dispersive viscoelastic on the cornea during surgery. All surgery was carried out with two-stage povidone iodine cleaning, careful draping and intracameral antibiotics.

The use of the clean room for surgery, in conjunction with the Toul Meditech Operio Mobile, was agreed with the local infection control team.

Patients’ various arrival and departure times were all collected prospectively. The initial 100 patients were contacted by telephone two weeks after cataract surgery to answer a short questionnaire regarding any post-operative complications, development of COVID symptoms and satisfaction (using a Likert scale). Departmental records regarding attendance with post-operative endophthalmitis were also interrogated.

After the initial 100 patients, another 215 consecutive patients underwent surgery in the same clean room, with all patients undergoing follow-up with local optometrists. The same equipment was then procured to reproduce the operating environment in two other geographic locations in Herefordshire, within outpatient clean rooms elsewhere. Using the same protocols as above, a further 954 consecutive patients underwent routine phacoemulsification surgery, with all using the Bausch & Lomb Stellaris and 2.2 mm incisions. All of these 954 patients were followed up in person by the operating surgeon in every case.