A 51 y.o. diabetic comes in with sudden onset of severe pain in the L eye

He is seen by ophthalmology and after their eval his eye appears in the picture below. US and eye pressures were normal.

What could be wrong?

Our patient had scleritis.  He had been dilated by ophthalmology using the usual 10% phenylephrine drops.  This normally vasoconstricts the surface of the eye so conjunctivitis or episcleritis would resolve but deeper inflammation( like scleritis) would still appear red. 

The eye has three basic layers: the fibrous layer or sclera, the vascular layer or uvea( iris, ciliary body and choroid)  and the nerve layer or retina.  Each of these can be involved in disease processes.

the sclera is the outer fibrous layer of the eye

Scleritis is a severe, destructive, inflammation causing severe pain.  Patients have photophobia and tearing.  It can be caused by immune processes including infectious processes like tuberculosis , herpes, syphilis, and  parasites or immune processes like rheumatoid arthritis,crohn’s disease, sarcoid,  or lupus.  Trauma, postsurgical inflammation or chemical exposure can also cause scleritis.

loa loa, a parasite being removed from the sclera

Scleritis is of several types with diffuse anterior such as in in our patient being most common. Nodular scleritis is the second most common form.  Necrotizing scleritis is the most severe  and can result in globe perforation.

necrotizing scleritis from rheumatoid arthritis.

Our patient was treated with prednisolone and cyclopentolate as well as ibuprofen 600mg tid .  His evaluation for autoimmune disease was negative and he recovered. 

While ophthalmologists use phenylephrine to test for scleritis,  other drugs will also “get the red out”.  The common drug used is Visine.  Its active ingredient is tetrahydrozoline which is a member of the imidazole family and causes hypotension if ingested.  In fact, it has been implicated in several murders. 

https://www.nytimes.com/2020/01/17/us/visine-eye-drop-poisoning.html

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Lin P, Bhullar S, Tessler H, et al. Immunologic markers as potential predictors of systemic arutoimmune disease in patients with idiopathic scleritis. Am J Ophthalmol 2008:145:463.