OcuLearning › Cornea
Thygeson Superficial Punctate Keratitis
ROUTINE — Cornea
Symptoms
- foreign body sensation: mild-to-moderate "gritty" feeling
- photophobia and tearing: sensitivity to light without significant discharge
- white eye: strikingly, the patient has NO history of a "red eye" during flares
- chronic relapsing: symptoms come and go over months or years, often asymmetrically
Clinical Findings
The "quiet eye" sign (pathognomonic)
- white conjunctiva: the eye looks perfectly calm and uninfljected despite the corneal lesions
- no discharge: distinguishes it from viral or bacterial conjunctivitis
Characteristic lesions
- coarse opacities: snowflake-like or "stellate" (star-shaped) gray-white intraepithelial dots
- location: scattered predominantly across the central cornea (usually 5–30 lesions)
- raised surface: the dots are slightly elevated and can be "felt" with a fluorescein strip
- variable staining: active lesions stain lightly with fluorescein; older ones barely stain
Etiology
Idiopathic
- suspected viral or immune link, but no specific pathogen has been proven
- course: a decades-long cycle of exacerbations and remissions
- burnout: the disease eventually resolves on its own without leaving any scars or vision loss
Red Flags
- steroid side effects: chronic use of even mild steroids requires monitoring for IOP spikes and cataracts
- corneal thinning/infiltrates: if the cornea starts to thin or look "cloudy" (stromal), reconsider the diagnosis (e.g., HSV or Adenovirus)
- atypical response: failure to improve with low-dose steroids should trigger a referral for a corneal specialist
Investigations
Slit lamp exam
- identify the classic coarse, snowflake-like epithelial lesions
- confirm the total absence of conjunctival injection or corneal edema
Clinical history
- absence of prior "pink eye" or cold sores (HSV) helps confirm the diagnosis
Treatment
Acute management
- mild steroids: Fluorometholone or Loteprednol qid, then taper slowly as symptoms resolve
- lubrication: preservative-free artificial tears for comfort during minor flares
Long-term maintenance
- cyclosporine 0.05%: often the preferred treatment to prevent relapses without steroid risk
- avoid: high-potency steroids or unnecessary topical antivirals
Clinical Pearl
Thygeson is benign but relapses for years — reassure the patient that the coarse intraepithelial dots come and go, and resist the urge to chase it with strong topical steroids.
Differential Diagnosis
- • adenoviral keratitis (presents with red eye, follicles, and subepithelial infiltrates)
- • herpes simplex (hsv) (true dendrites with terminal bulbs; usually unilateral)
- • dry eye syndrome (staining is usually inferior or band-like, not coarse snowflake dots)
- • medicamentosa (toxicity from other eye drops; eye is usually red and irritated)