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The typical patient with superior limbic keratoconjunctivitis (SLK) is a woman aged between 20 and 60 years of age with chronic red and irritable eyes.1 Although both eyes are usually affected, the condition maybe asymmetrical.1 After episodes of exacerbation and remission it usually resolves. The patient may also have abnormal thyroid function.2
SLK has been treated with silver nitrate or thermal cauterisation of the superior bulbar conjunctiva, pressure patching, and large diameter bandage contact lenses (BCL), topical trans-retinoic acid 0.1%, and recession or resection of the superior bulbar conjunctiva.1, 3 Over 50% of patients with SLK are said to have keratoconjunctivitis sicca4 and recently upper punctal plugs have been used to treat SLK.5
We report two cases in which a unilateral BCL wear ameliorated the symptoms of bilateral SLK and a possible explanation is discussed.
A 38 year old woman presented with a 3 month history of irritable photophobic eyes that were unresponsive to preserved lubricants. Her right eye was amblyopic. On systemic review she reported weight loss, heat intolerance, and insomnia.
Slit lamp examination revealed bilateral superior conjunctival hyperaemia, superior punctate epithelial erosions, and four to five filaments and micropannus on the superior cornea of each eye. Both superior tarsal conjunctivae had moderate papillary reactions. Schirmer's test without anaesthesia was 14 mm on the right and 15 mm on the left at 5 minutes. Non-preserved lubricants every 1–2 hours and Lacrilube ointment at night were prescribed. Thyroid function tests revealed hyperthyroidism and she was referred to an endocrinologist who commenced carbimazole.
Three months later she returned still complaining of persistent severe discomfort, photophobia, and a burning sensation in both eyes. The ocular examination was unchanged. A silicone hydrogel BCL (Pure Vision, Bausch and Lomb, 36% water content) was inserted into the right eye and within an hour she had symptomatic relief in both eyes. Non-preserved lubricants were continued for the left eye.
On review 2 months after insertion of the BCL she remained asymptomatic. Mild superior limbal hyperaemia on the right and punctate staining of the superior conjunctiva and adjacent cornea on the left were found on examination.
A 54 year old woman was referred with a 3 year history of sore, gritty eyes, worse on the left. The tear break up time was <10 seconds and Schirmer test without anaesthesia was right 0 mm and left 1 mm after 3 minutes. There was some relief from lubricants, though on occasion the pain was so severe that she required oral analgesia.
On examination punctate epithelial erosions were found on the superior bulbar conjunctiva of both eyes, but were more marked on the left (Fig 1). A silicone hydrogel BCL (Pure Vision, Bausch and Lomb) was inserted into the left eye, which rapidly ameliorated the symptoms in both eyes. Lubricants were continued for the right eye.
Three months later she remained asymptomatic and no fluorescein staining was seen. The BCL was removed. Within a month her bilateral ocular discomfort returned and the left BCL was refitted with immediate symptomatic relief in both eyes. Two months later the BCL was lost and her bilateral ocular discomfort recurred within 2 days. Since then her BCL has been replaced every 3 months. Occasionally she has used lubricants for the right eye.
One year following her presentation she became tachycardic and hyperthyroidism was diagnosed. Her endocrinologist commenced carbimazole and β blockers. Her treatment was later changed to propylthiouracil after she suffered from carbimazole induced arthralgia. Thyroid function tests were normal 6 months later and the propylthiouracil was stopped.
The pathogenesis of SLK is unclear. It may be the result of mechanical irritation from increased pressure of the upper eyelid against the globe and/or increased motility of the upper bulbar conjunctiva from hypothyroidism or ageing.2, 6 Increased upper eyelid tightness may be the result of thyroid eye disease or chronic inflammation and, in addition, may impair the normal turnover of bulbar conjunctival epithelial cells.2, 6 This may be aggravated, in some patients, by blepharospasm, which increases the force on the globe.1, 3
Therapeutic lenses can produce rapid symptom relief in SLK.2, 3 They may be helpful in the treatment of SLK as they relieve pain, facilitate healing of punctate epithelial erosions by protecting the ocular surface from the eyelids, reduce upper lid pressure on the globe, and alter tear dynamics.7 During blinking as the upper lid moves downwards to meet the lower lid significant forces are exerted on the globe.8 The lens can reduce the force on the superior limbus from blinking as it has a lower mechanical stiffness and elastic modulus.3, 9
In the first week of contact lens wear tear production increases dramatically and tear tonicity decreases.8 Tear production then normalises and tear tonicity rises as evaporation increases.8 A lens may then aid aqueous tear deficiency, which can accompany SLK,4 by ensuring a continuous precorneal tear film.7
It is difficult to be certain of the mechanism of bilateral symptom relief from unilateral BCL wear in SLK. One possible explanation is that BCL wear reduces the tactile corneal reflex, measurable 1–2 hours after lens insertion, and this reduction, which increases with the duration of lens wear, would then decrease bilateral reflex blinking.8, 10 This would protect the superior limbus in both eyes from the mechanical friction associated with blinking and may also break the cycle that leads to blepharospasm in SLK.3
It should not be forgotten that continuous BCL wear carries risks including microbial keratitis and corneal vascularisation.6, 11 New extended wear silicone BCL, as used in our patients, increase oxygen transfer and have been shown to reduce such risks.11