Q: When a contact lens patient presents with a red eye and/or infiltrates, what should I look for first?

A:Consider the worst things first, says Art Epstein, O.D., of North Shore Contact Lens & Vision Consultants, Roslyn, N.Y. Your mindset needs to be: If the patient appears to have an infectious process, then the patient has an infectious process until proven otherwise.1

Take the patients history, but remember that he or she may not know what information to give you. Patients may present saying that they scratched their eye while removing their lenstheyre actually describing the sensation of removing their lens after contracting an infection, says Dr. Epstein. Its incumbent upon the clinician to translate the patients complaints.

Find out when the patients symptoms began, how long theyve been persisting, and if theres been any change in the level of pain. If the patient says, I woke up yesterday with minor discomfort, and by the afternoon, I took my lenses out and my eye was still hurting, and now its only continued to get worse, then youre probably looking at a bacterial infection, says Dr. Epstein.

Bacterial infection, or microbial keratitis (MK), is the worst-case scenario where you should start creating your differential diagnosis. The paradigm for diagnosing and treating: Your first expectation has to be bacterial, says Dr. Epstein. These can spiral out of control very quickly. Consider it bacterial unless you have reason to believe otherwise, such as contact with water or trauma involving vegetative material.

Look for worsening pain, redness, discharge, lid edema and a strong anterior chamber reaction.1 Lesions may not be central, but they will typically be greater than 1mm in diameter, with possible satellite lesions (in advanced cases).

If the patient has been experiencing discomfort for two weeks on and off, and it hasnt increased or decreased in severity, I might think fungal. Such infections tend to start slowly with intermittent, varying pain, says Dr. Epstein.2

Or, if the patient complains of constant pain that has improved after taking aspirin or using a cold compress, That generally means youre dealing with a sterile process, he says. Look for a lesion that is small, round and well-demarcated.1,3

But, early MK may produce an ulcer similar in appearance to a sterile infiltrate, and lesions in both infectious and sterile events will most likely scar the cornea.1,4

Dont rule out contact lens-induced acute red eye (CLARE). Patients may present with a very red eye and significant pain, says Dr. Epstein. Visual acuity will not be significantly affected, and while the patient may present with infiltrates, there is usually no anterior chamber reaction.5

CLARE is associated with non-virulent forms of gram-negative bacteria (e.g., Pseudomonas), so there is no infection, but a lot of inflammatory response, Dr. Epstein says.3 Go through the diagnostic workup for a red eye. What is causing the inflammation? he asks.

And remember, adds Dr. Epstein, Always start with the worst in your differential diagnosis.

Next month: Management, follow-up and prevention.

 

Typical Characteristics of Sterile vs. Infectious Infiltrates1,3
Sterile Infiltrates	Infectious Infiltrates
Smaller lesion ( < 1mm)	Larger lesion ( > 2mm)
More peripheral	More central
Minimal epithelial damage (Defect size is comparable to underlying infiltrate.)	Significant epithelial defect (Size of staining defect closely mirrors size of underlying stromal lesion.)
Little to no discharge, usually mucoid	Mucopurulent discharge
Less pain and photophobia	Pain and photophobia
Little to no anterior chamber reaction	Anterior chamber reaction
Little to no edema	Lid edema

1. Silbert JA. Is it an ulcer or an infiltrate? Rev Optom 2007 Jun 15;144(6):91-101.

2. Heinz T, Perfect J, Schell W, et al. Soft-tissue fungal infections: surgical management of 12 immunocompromised patients. Plast Reconstr Surg 1996 Jun;97(7):1391-9.

3. Stein RM, Clinch TE, Cohen EJ, et al. Infected vs. sterile corneal infiltrates in contact lens wearers. Am J Ophthalmol 1988 Jun 15;105(6):632-6.

4. Silbert JA. Corneal infiltrative complications associated with contact lens wear. Rev Optom 2004 Apr 15;141(4):95-102.

5. Bowling E, Russell G. Relieve red eyes right away. Rev Cornea Contact Lens 2008 May;144(4):22-6.