Quantification of aerosol generation during cataract surgery.

PURPOSE: To determine whether phacoemulsification cataract surgery is an aerosol-generating medical procedure (AGMP) and, therefore, to help determine the personal protective equipment required by healthcare providers in the era of the COVID-19. SETTING: The Surgery, Teaching and Research Wet Lab of the Department of Ophthalmology and Visual Sciences, Faculty of Medicine, UBC. DESIGN: Laboratory-based simulation. METHODS: Phacoemulsification cataract surgery was performed on porcine eyes. At a fixed distance, a DRX Aerosol Monitor 8534 (DustTrak) was used to measure particulate matter (PM) mass fractions for each of 3 particle sizes, PM1, PM2.5, and PM4 (in microns), every 2 seconds during surgery and for 1 minute after. The main outcome measure was an increase in the mass fraction of aerosolized particles of various sizes. RESULTS: There was no significant aerosolization of particles during cataract surgery for both the 2.4 and 2.75 mm wound sizes. CONCLUSIONS: Phacoemulsification cataract surgery was not found to be an AGMP. In the midst of the COVID-19 pandemic, ophthalmologists can continue to use droplet precautions while performing this surgery.

The use of dry amniotic membrane in pterygium surgery.

Pterygium is a fibrovascular growth of the bulbar conjunctiva that crosses the limbus and extends over the peripheral cornea, in some cases resulting in significant visual morbidity. When treatment is indicated, surgery is necessary, and several management options exist. These include excision, conjunctival autografting, and the use of adjuvant therapies. This paper reviews the incidence and prevalence of pterygia and also describes the various techniques currently used to treat this condition. These management options are compared to the use of dry amniotic membrane grafting (AMG), specifically with regard to recurrence rates, time to recurrence, safety and tolerability, as well as patient factors including cosmesis and quality of life. AMG has been used in the treatment of ocular surface disease due to a variety of benefits, including its anti-inflammatory properties, as well as its ability to promote epithelial growth and suppress transforming growth factor-ß signaling and fibroblast proliferation. However, rates of recurrence for AMG following pterygium excision still surpass other commonly used techniques, including conjunctival and limbal autografting. Nevertheless, there are circumstances in which AMG may be most beneficial to the patient, such as when preexisting conjunctival scarring is present, when the conjunctiva must be spared for future glaucoma filtering surgery, or in cases of large or double-headed pterygia. Therefore, surgeons should be prepared to offer this procedure as an option to their patients for the treatment of pterygia.

Paediatric infectious keratitis at tertiary referral centres in Vancouver, Canada.

OBJECTIVE: To report the clinical and microbiological profiles of paediatric patients with infectious keratitis in Vancouver, Canada. DESIGN: In this observational case series, the microbiology results and medical records of 17 eyes with microbial keratitis in 16 children aged 17 years or younger were retrospectively reviewed. These patients had undergone corneal scraping between May 2006 and April 2011 at BC Children's Hospital or Vancouver General Hospital Eye Care Centre in Vancouver, British Columbia, Canada. Demographic information, clinical features, predisposing factors, results of microbiology studies, antibiotic susceptibilities, treatment course and outcomes were analysed. RESULTS: The mean age of patients was 11±5.7 years (range 1-17 years) and the male:female ratio was 1.4:1. Major predisposing factors were contact lens wear (6/17; 35%), and pre-existing ocular surface conditions including blepharitis (3/17; 18%) and Stevens-Johnson syndrome (3/17; 18%). Four patients had a previous corneal ulcer. The most commonly isolated microorganisms were Staphylococcus epidermidis and Acanthamoeba. Acanthamoeba was isolated in 67% of contact lens-related corneal ulcers, while the remaining 33% of contact lens-related corneal ulcers were associated with infection with Pseudomonas aeruginosa. Final visual acuity was better than 20/60 in 9 out of 16 patients (56%). Three patients subsequently required surgical management with either penetrating keratoplasty or deep anterior lamellar keratoplasty for treatment of corneal scarring. CONCLUSIONS: Contact lens wear and pre-existing ocular surface conditions are significant risk factors for the development of infectious keratitis in our paediatric population. Knowledge of regional patterns of infection and susceptibility are essential in ensuring prompt treatment of this potentially sight-threatening condition.