The ‘acute red eye’ is a common ophthalmic presentation to primary health care. The majority of cases can safely and successfully be treated in the community. With the advent of combination preparations containing topical steroid and antibiotic such as Betnesol N® (betamethasone and neomycin) and Maxitrol® (dexamethasone and neomycin) there appear to be some who favour this ‘blanket’ treatment. Unfortunately, in doing so these patients run the small, but potentially devastating, risk of exacerbation of latent herpetic infection, secondary infection and increased intraocular pressures, the latter which may go unmonitored. While it is true that the majority of these patients who have been treated for red eye with these drops come to no harm, there are many potential pitfalls associated with this management strategy. Occasionally we encounter a few nasty and preventable surprises in patients presenting to an eye clinic with a history of topical steroid-antibiotic combination treatment for red eye of uncertain aetiology.
The main ophthalmic role of these preparations is for the prophylaxis of infection and inflammation after eye surgery and not in acute eye conditions, although even then their postoperative use is falling out of favour among some ophthalmologists due to the perceived corneal toxicity of neomycin.1
There are very few eye conditions that require initiation of topical ocular steroid therapy in the community. Red eye secondary to iritis in a patient with a long history of the condition who has learned to recognise the symptoms may be one rare indication, but caution needs to be exercised with an early hospital clinic review. Photosensitivity, tearing and red eye common to iritis can equally be symptoms of conditions such as herpes simplex keratitis, infective corneal ulcers and corneal abrasions where unsupervised improper use of topical steroids is known to be associated with adverse outcomes by masking symptoms, delaying wound healing, facilitating secondary infection and even causing progression of the condition.2
In herpes simplex keratitis, for example, the virus replicates more readily in the presence of topical steroids and under these conditions ulcers can develop3 (Figure 1) and worse, corneal stromal involvement with melting and perforation are possible sequelae. Permanent scarring can also result. The addition of an antibiotic such as neomycin does not make the treatment any safer and certainly makes the preparation even more toxic to the corneal epithelium.1
Figure 1 Herpes simplex corneal ulcer following 10 days of treatment with Maxitrol® (dexamethasone neomycin, polymyxin B) QDS for refractory red eye symptoms. This ulcer later perforated and the patient required emergency surgery followed by eventual corneal grafting.
With permission from the patient.
It needs to be highlighted that a high proportion of patients are ‘steroid-responders’,4 the mechanism of this rise in intraocular pressure secondary to medium-term topical corticosteroid use is not well understood. Patients with underlying primary open-angle glaucoma are at particular risk of these pressure spikes, which can lead to permanent sight loss from optic nerve damage.
There is certainly a role for using these drops in hospital settings where patients can be closely monitored, but in primary care they are less useful and significant caution needs to be exercised. For cases of red eye where the distinction between infective and inflammatory aetiologies is not clear cut the safest measure is to refer the patient to the local eye emergency service provider.
- © British Journal of General Practice, 2006.