This post will just scratch the surface in its exploration of the diagnosis and management of corneal abrasions.
What is the best technique for getting the fluorescin into the eye?
First of all, please don’t jab the patient’s eye with the fluorescin strip itself. You can actually cause a corneal abrasion that way. In the past I would drip the tetracaine (or saline) over the strip and let two drops run into the eye. But, a recent post on Academic Life in Emergency Medicine opened my eyes to some alternative techniques. This does involve a two step process, but I think the precision of fluorescin application makes up for the time it takes.
Step 1: Make your fluorescin solution
This innovative technique involves putting 2-3mL of sterile saline in a sterile specimen cup. Then, dip the fluorescin strip into the saline and let it dissolve.
Step 2: Assemble the dropper
Then, you can draw the fluorescin infused saline into a 5mL syringe with a 24G angiocath tip attached.
Should I prescribe topical antibiotics? Are drops better than ointment?
The simple answer is yes – you should prescribe topical antibiotics. Prevention of superinfection or reduced time to healing is not necessarily supported by robust evidence however. Ointments (erythromycin – 3-4 times a day for 5 days) may have advantages as a lubricant, but it does blur vision after application. Drops are also an option, and may be easier to instill in some pediatric patients. Options are varied and include:
- Sulfacetamide 10%
Amionglycoside drops (gentamicin) are potentially toxic to the corneal epithelium – so avoid them if possible. Do not prescribe steroid combo drops, since these may slow healing and increase risk of superinfection.
What is the best option for pain control?
Small (<8mm) abrasion generally heal in <1-2 days – many time over night if the lid is closed (no fish sleeping). Acetaminophen or ibuprofen are great choices here. Larger abrasions (>1cm) may take 48 hours or more to heal, and the pain can be significant. They certainly won’t heal overnight in most cases. Consider acetaminophen/oxycodone or similar agents for more significant pain.
For the rare patient with an abrasion covering >50% of the corneal surface you’ll probably end up consulting ophtho – but nevertheless cycloplegic drops (that inhibit pupil constriction) can help with the photophobia. Cyclopentolate 0.5% to 1% twice daily (shortest duration of action – still lasts 24-36 hours!) or homatriptine 2.5 to 5% once daily are options. Scopolamine or atropine can interfere with accommodation for weeks! So it goes without saying that you should not use them unless you are board certified in ophthalmology.Remember that cycloplegics cause mydriasis and interfere with reading etc,. So, ultimately, most abrasion heal in <2 days and thus these drops have limited utility – especially when discharging a patient home from the ED.
Wait, why not tetracaine for pain control?
Tetracaine drops can absolutely help with the exam in the Emergency Department. But, you should not send a patient home with them. In fact, don’t leave the bottle behind in the room as unscrupulous patients may abscond with it. In animal studies repeated use of topical anesthetics like proparacaine 0.5% delay healing. Anecdotal evidence suggests that repeated use by human patients in a non-healing corneal injury may lead to ulceration, perforation or scarring.
It is true that in a small study patients randomized to proparacaine numbing drops had better pain control without delayed healing. However, the sample size was tiny, and the drops were diluted 10-fold by an eye doctor. Another study with tetracaine for 24 hours showed no difference in VAS pain scores – though patients seemed to like it more.
So, basically, prescribing topical anesthetics is not a good idea for many reasons – but if you need to justify this with the parents who says that “the drops worked so well in the Emergency Department – why can’t I have them?” I would recommend saying the following:
- Most small abrasions – which you will see way more of than anything else – heal overnight
- Dilute preparations may be safe – but numbing drops are hard to come by in outpatient pharmacies, and in the concentrations provided may delay healing, mask symptoms or further damage the cornea