Case
A 46-year-old woman presents with a two-day history of a foreign body sensation in the left eye and blurred vision. There is no history of trauma or injury, but she has an ocular history of dry eyes.
Examination using fluorescein drops reveals a large corneal abrasion and the patient is treated with chloramphenicol and discharged.
She returns three days later with non-resolving symptoms. Again, examination shows a large corneal abrasion. At this visit her upper lid is everted, revealing a large concretion in the tarsal conjunctiva. The concretion is removed under topical anaesthetic using a needle; the patient is advised to continue with her chloramphenicol ointment for five days and discharged.
The problem
Conjunctival concretions – or lithiasis – are small white or yellow nodules lying within or beneath the tarsal conjunctiva. They are composed of the mucinous secretion of transformed conjunctival glands, mixed with the degenerative products of epithelial cells. They are associated with chronic ocular inflammatory conditions such as dry eyes and blepharitis. They are also seen in patients undergoing haemodialysis for chronic renal failure, due to calcium deposition in the conjunctiva.
Concretions are common – they are reportedly seen in 42% of the population. But only a small proportion of these will be symptomatic and only symptomatic patients need referral or treatment.
Features
- If symptomatic, patients experience a foreign body sensation or features of a corneal abrasion – pain, watering or red eye – with staining of the concretion and abrasion in the presence of fluorescein (see pic below)
- Symptoms do not respond to antibiotic drops
- Vision is rarely impaired unless the patient develops a large central corneal abrasion
- It is associated with conditions of chronic ocular inflammation, such as dry eye and blepharitis.
Differential diagnosis
- Corneal foreign body – usually associated with trauma, the foreign body may be seen on the cornea
- Conjunctivitis – usually bilateral, associated with discharge, often family members are affected
- Blepharitis
- Dry eye
- Microbial keratitis – painful, blurred vision, usually associated with contact lenses.
Examination
- Check visual acuity in each eye, with glasses on if needed
- Instil fluorescein, if possible, to identify any corneal abrasions – the abrasions seen in this patient are pictured online
- If the patient is in pain, instil proxymetacaine 0.5% to provide relief and permit measurement of vision and examination
- Evert upper lid under topical anaesthesia with proxymetacaine 0.5% to examine for concretions or foreign bodies, which will stain with the fluorescein.
Referral
- Urgent referral is not required unless the patient is in severe pain
- Early referral is recommended for foreign body symptoms
- If found incidentally in an asymptomatic patient, concretions do not require referral.
Treatment
Symptomatic concretions require removal under topical anaesthesia. Most GPs will delegate this task to the local ophthalmologist.
Following removal, the patient is given chloramphenicol ointment qds for five days. If the patient has a corneal abrasion they should be given chloramphenicol ointment qds for five days and warned that the eye will be sore until the abrasion heals.
During the healing phase of a corneal abrasion, some advocate patching the affected eye, but the evidence suggests that this is not necessary.1
No follow-up is required, although patients should be encouraged to return if the pain does not settle within two days.
Miss Claire Daniel is a consultant ophthalmic surgeon and Miss Lucy Barker is a specialist registrar, at Moorfields Eye Hospital, London.
References
1 Turner A, Rabiu M. Patching for corneal abrasion. Cochrane Database Syst Rev 2006; 19(2):CD004764
