Eyes that go 'ouch' in the night
In the last of his series on common eye problems, Dr Scott Fraser looks at conditions that result in loss of epithelium during the night
There are three eye conditions that are little known outside ophthalmology which can result in patients waking with a sudden pain in one or both eyes. Although each has a different mechanism, all result in a disturbance of the corneal epithelium. Because the area lost is small, it usually heals rapidly and the pain settles within a few hours. If the patient is seen later in the day the eye will no longer be sore and examination may be normal. Diagnosis is usually made on the history.
Recurrent epithelial erosion syndrome (RES)
This is seen fairly commonly in eye departments but many non-ophthalmologists are unaware of its existence. Sufferers complain of waking with a sudden pain in one eye that settles within a few hours. It may occur every night for some days or weeks and then settle or may only occur on occasional nights.
Most patients, when questioned, will give a history of a traumatic corneal abrasion. It is thought that this epithelium does not attach itself completely to its basement membrane.
For some reason, during sleep this abnormal area of epithelium comes away completely from the basement membrane creating a spontaneous
l If the abrasion remains when you see the patient, treat as any other corneal abrasion – some patients prefer an eye pad, but healing occurs just as quickly if you give antibiotic ointment four to six times a day. If the patient is in great pain give cyclopentolate drops (two to three times a day until comfortable). The patient should be warned not to drive until the eye feels normal.
l Explain to the patient what RES is – this is important for long-term compliance with treatment.
l Treatment aims to allow the abnormal area of epithelium to adhere properly to its basement membrane. Prescribe simple eye ointment to be used just before turning the light off to go to sleep. This coats the cornea and protects the epithelium. It is important for the patient to realise that they need to use this every night for at least three months to allow complete healing. Many patients stop when their eye feels fine.
l If they are following this regime but still getting attacks it may be worth substituting 5 per cent sodium chloride ointment – again it needs to be used for at least three months.
l If the patient, after trying this regime, is still getting attacks or the attacks are getting more frequent or disabling, they should be referred.
Floppy eyelid syndrome
Patients complain of irritation, redness and stringy discharge on waking. It is usually a bilateral condition but patients often complain of one eye being worse than the other.
The diagnosis is easily missed. It should be suspected in overweight patients (more frequently males) who wake with gritty, sore eyes. It is thought to be due to an excessively lax upper lid that spontaneously everts during sleep, leaving an area of conjunctiva or cornea exposed. This exposed area dries out and on waking, is uncomfortable for a variable amount of time.
l There may be little to find on examination but an important sign is that the upper lid can be very easily everted. In most young people, reflex squeezing of the lids makes it difficult to evert the upper lid, but in patients with floppy lid syndrome it is much easier.
l It is important to think of other differential diagnoses:
Infective conjunctivitis – this will have a shorter history and rather than a stringy discharge the eyelids will be stuck together in the mornings
Allergic conjunctivitis – itch is a more predominant symptom
Mucous fishing syndrome – this occurs when the sufferer attempts to remove mucous strands from their conjunctivae. This can cause mechanical damage to the conjunctiva, causing further mucous production, and a vicious cycle ensues. It is worth asking the patient directly if they are doing this and explaining why they should stop.
l Ocular treatment involves keeping the eye lubricated during sleep:
m Lubricating last thing at night with simple eye ointment
m Persist with this for a number of weeks
m Warn the patient that the eye may be a little smeary in the morning
l It is likely to be helpful if the patient loses weight.
l If symptoms persist despite these measures, refer to an ophthalmologist as lid surgery can help.
Lagophthalmos is incomplete closure of the eyelids and, again, can result in corneal exposure and drying with epithelial loss. It can occur in otherwise normal eyes but is more common after lid trauma, or with orbital abnormalities such as thyroid eye disease.
Suspicion is aroused when the patient complains of waking with painful eyes, which settle within a few hours. Examination may be normal, but if the patient is seen soon after the event they may have a small area of corneal staining when fluorescein is applied. Ask the patient to tightly close their lids and look for any areas of incomplete closure. It may be worth asking the patient's partner if they can observe the patient asleep to ascertain whether they are completely closing their lids.
A history of eyelid surgery or injury, facial palsy or thyroid eye disease may be a further clue. Examine the lids for notches, scarring and proptosis.
l Explain the condition. If the patient has lid abnormalities or proptosis of the globe they should be referred to an ophthalmologist.
l It is important to check if the patient has good Bell's phenomena. This is the normal reflex in which the eye rotates upwards when the lids are closed. It is a protective mechanism for the cornea and if lost in the presence of incomplete lid closure – for example facial nerve palsy or globe proptosis – the cornea is at much greater risk of being damaged. Bell's phenomena are examined by holding the patient's lid open and asking them to try to close their lids – if it is present the eye should be seen to roll upwards and cornea to become hidden.
If the reflex is not present you need to have a low threshold for referring the patient to an eye department.
l If the patient has good Bell's phenomena try simple eye ointment last thing at night. This coats the cornea and prevents drying.
l If this is not successful in alleviating symptoms the patient can try (gently) taping the lid shut
at night. It may be easier if they ask their partner
to do this.
l There is a trio of conditions that can cause patients to wake with pain in one or both eyes
l These conditions are often missed but the diagnosis is usually made from the history
l A common feature of them all is a disturbance of the corneal epithelium which causes the resulting symptoms
l Treatment is aimed at long-term protection of the epithelium by simple lubricants
l If the symptoms are not settling, if they are getting worse, or if the patient has reduced Bell's phenomena they should be referred to an ophthalmologist
Floppy lid syndrome www.emedicine.com/OPH/topic605.htm
Scott Fraser is consultant ophthalmologist at Sunderland Eye Infirmary and co-author of Eye Know How (BMJ Books, 2000)