The material chosen can be a consensus among ophthalmologists locally Our experience is that the film should ideally be transparent to allow the examiner and the patient to see each other, and firm enough The study found that the spectrum of suitable material ranges from those that are firmer and stiffer, e g acrylic, to softer and more flexible, e g document folders and binding covers made of polyvinyl chloride (PVC) or polypropylene Firm plastic is ideal as it minimises the chance of the film springing back and forth, the movement which can be easily caused by the examiner's hand accidentally touching the film during examination However, one should note that thicker plastic may not be able to fit and it is not possible to cut safely with office tools Sticking a few pieces of thinner films together by thermal lamination is therefore an option The study also suggested using X-ray or MRI photographic film One may also expose the film to achieve transparency The Centres for Disease Control and Prevention (CDC) guidelines for disinfecting face shields were observed as slit lamp shields serve a similar role Along with slit lamps and table surfaces, they were cleaned with wipes containing 70% alcohol and allowed to air dry after each clinic session