This patient has scleritis. Scleritis refers to inflammation of the sclera and surrounding vessels. While most commonly autoimmune in nature, it can also be infectious. In contrast to episcleritis, which is inflammation of the more superficial episclera, scleritis is associated with dull, boring, pain that is exacerbated by eye movements. It is most commonly associated with rheumatoid arthritis.
Another way to distinguish episcleritis from scleritis is with application of a topical drop of phenylephrine. With inflammation of more superficial tissue and vessels (as in episcleritis) blanching of the injection will occur. However, the injection will persist with scleritis due to inflammation of deeper tissues and vessels.
First line treatment for scleritis is oral NSAIDs. However, sometimes oral steroids are required to manage the inflammation. In recurrent cases, steroid sparing agents are required long term to control inflammation. Recurrent episodes of scleritis can lead to thinning of the sclera, which leads to a “bluish” hue of the thin sclera.
Other causes of “Red eye”
Other causes of red eye are listed in the differential diagnosis for this case including blepharitis, dry eye syndrome, conjunctivitis, subconjunctival hemorrhage, corneal ulcer, corneal abrasion, uveitis, pterygium, and preseptal cellulitis.
Chronic dry eye syndrome and blepharitis can cause redness of the conjunctiva which is usually diffuse and bilateral. Blepharitis refers to inflammation of the eyelids and meibomian glands which produce an essential part of the tear film, and leads to dryness symptoms. It may be characterized by crusting around the lashes. When one particular meibomian gland becomes clogged, this leads to build of tear film in the duct which forms a bump on the eyelid which is referred to as chalazion. Preseptal cellulitis refers to infectious inflammation of the eyelid which can be caused by a chalazion, but is not the only cause.
Subconjunctival hemorrhages are collections of red blood cells within the conjunctival from a broken conjunctival blood vessel. They hemorrhages are usually sectoral and form a solid red appearance. These commonly occur after eye rubbing, valsalva maneuver, and less frequently with poorly controlled hypertension. (side image credit, license: CC BY-SA 3.0)
A pterygium develop from UV exposure causing elastoid degeneration to the conjunctiva which then grows onto the cornea. These are benign growths but must be monitored for obstruction of the visual axis. If they are approaching the visual axis or frankly obstructing it, surgical excision is considered. However, they may recur. (side image credit, license: CC BY-SA 3.0)
Uveitis may cause sectoral or diffuse conjunctival redness, but is typically characterized by significant photophobia.
Conjunctivitis refers to inflammation of the conjunctiva which has myriad etiologies including infectious, inflammatory, allergic, and toxic (commonly topical medication induced). It is characterized by redness and inflammation of the entire conjunctiva, including the portion which lines the inner aspects of the eyelids. Associated purulent discharge is suggestive of a bacterial etiology, whereas viral etiologies may be accompanied by tearing but not discharge.
Hyphema refers to collection of red blood cells in the anterior chamber and is most commonly caused by trauma leading to iris vessel injury and bleeding into the anterior chamber. In this example image, there is a mild subconjunctival hemorrhage located inferiorly as well. (side image credit, license: CC BY-NC-ND 3.0)
Finally, corneal pathologies, such as abrasions and ulcers, may be cause conjunctival injection due to the eye’s inflammatory response to this insult. These are characterized by severe, sharp eye pain due to the significant innervation of the cornea. A corneal abrasion refers to de-epithelialization of the cornea while a corneal ulcer refers to a break in the epithelial with associated infiltrate. In addition to redness of the conjunctiva, breaks in the corneal epithelial will be highlighted by fluorescein staining and presence of infiltrate may cause an opaque appearance to portions of the affected cornea.
References and Additional Resources:
- “Eyewiki: Scleritis.” Available at: https://eyewiki.aao.org/Scleritis.
- Oray M, Meese H, Foster CS. Diagnosis and Management of Non-Infectious Immune Mediated Scleritis: Current Status and Future Prospects. Expert Rev Clin Immunol. 2016;12(8):827-37.
- Pflipsen M, Massaquoi M, Wolf S. Evaluation of the Painful Eye. Am Fam Physician. 2016;93(12):991-998.