Corneal Clarity
Do you know SLK?
Superior limbic keratoconjunctivitis is under diagnosed among ocular surface diseases.
By Thomas John, MD
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Thomas John, MD, a world leader in lamellar corneal surgery, is a clinical associate professor at Loyola University at Chicago, and in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. Dr. John has financial relationships with Bausch + Lomb, Bio-Tissue, Inc. and iScience Corp.; he is a speaker for Allergan. His e-mail is tjcornea@gmail.com. |
Superior limbic keratoconjunctivitis (SLK) is an ocular surface disease, although if it doesn’t immediately spring to mind, don’t feel too badly; it is also under diagnosed and under treated. It is under diagnosed because SLK often exhibits general symptoms that may be common to many other OSDs, including superior conjunctivochalasis. Another significant reason, however, has to do with how we approach the clinical examination of the ocular surface. To recognize and diagnose SLK, we must reorder our examination pattern and more carefully scrutinize the signs the patient is exhibiting.
NEW ORDER OF THE EXAM
The three L’s
Let’s consider the exam. While we usually go straight for the corneal surface and maybe the bulbar conjunctiva during the slit-lamp examination, I believe it is clearly time for us to reverse our pattern of how we examine the ocular surface. When scanning the ocular surface as part of a clinical examination, I would urge you to focus first on the “three L’s”:
- Lid – upper.
- Lid – lower.
- Limbus.
The upper lid zone includes the OSDs SLK, conjunctivochalasis and blepharitis, while the lower eyelid zone includes dry eyes, conjunctivochalasis and blepharitis (both anterior and posterior). The limbus region houses limbal stem cell deficiency states. Hence, the three L’s for the most part encompass all the major OSDs. The bulbar conjunctival and corneal surface will provide more findings for dry eye states.
The order of the exam
When it comes to detecting SLK, it is imperative that you focus on the upper eyelid. In fact, if you do not lift the upper lid, you will miss the diagnosis of SLK. To avoid missing crucial information, here is the order I suggest you follow:
- First, lift the upper eyelid and check if SLK exists, then look at the upper lid margin for superior conjunctivochalasis; then glance at the upper lid margin to detect any anterior blepharitis.
- Move onto the lower lid margin and check the tear meniscus for any clue to aqueous-deficient dry eyes and conjunctivochalasis that may be present in the temporal or nasal quadrants, or along the entire lower eyelid margin. Lastly, look for both anterior and posterior blepharitis. The lower eyelid strip is more easily accessible to look for posterior blepharitis. Apply the squeeze test if needed to partially extrude the meibomian gland secretions.
- Having looked at the upper and lower eyelids, next examine the limbal region of the globe to check for limbal stem cell deficiency.
- Lastly, visit the most popular region of examination — the corneal and bulbar conjunctival surfaces.
This method of examination will help you make the correct diagnosis relating to ocular surface diseases, and for the most part not miss important clinical entities of the ocular surface.
THE SYMPTOM CONUNDRUM
Overlapping symptoms
Another hurdle in the ocular surface domain is the fact that symptoms are largely non-specific and overlap with various other OSDs. Overlapping symptoms among OSDs include irritation, discomfort, pain, blurred vision, redness and itching. The same general symptoms are common to OSDs such as Sjögren’s syndrome, conjunctivochalasis, ocular allergy, medicamentosa, chemical burns (acid and alkali), thermal burns, meibomian gland dysfunction that can contribute to evaporative dry eyes, ocular cicatricial pemphigoid, pterygium, Steven-Johnson syndrome, toxic epidermal necrolysis, limbal stem cell deficiency and ocular surface tumors. The SLK patient may complain of a burning sensation, foreign-body sensation, discomfort and photophobia.
Because these symptoms alone do not provide a definitive clinical diagnosis, you must go beyond the spectrum of ocular symptoms and look for ocular surface signs that may help in making a diagnosis and then determine a treatment. Otherwise, misdiagnosis can easily occur. You may miss conjunctivochalasis or mistake it for dry eyes. In such cases, treatment for dry eyes with tear substitute and tear stimulators may have little effect, if any, on conjunctivochalasis; in fact, it may make the symptoms of conjunctivochalasis worse.
Similarly, if a patient is on multiple glaucoma medications with preservatives that compromise the ocular surface epithelium, you may mistake it for dry eyes and treat it as such without any relief of the symptoms and signs. Further, the misdiagnosis ends up increasing the patient’s chair time. Making the correct diagnosis is the key to successful management of ocular surface diseases.
Rely on the signs
Clinical signs of SLK include superior bulbar conjunctival inflammation with significant involvement of the superior limbus, prominent superior bulbar conjunctival hyperemia with vertical blood vessel engorgement, superior bulbar conjunctival thickening or keratinization clearly visible with rose Bengal staining, superior corneal epithelial keratitis, punctate corneal epithelial erosions that involve the superior one-third of the cornea with or without filaments, and upper tarsal conjunctival fine papillary hypertrophy. Again, lifting the upper lid can clinch the diagnosis of SLK.
COURTESY: SCHEFFER TSENG, MD, PHD.
Superior bulbar conjunctiva in a case of SLK. The arrows show hyperemia with vertical blood vessel engorgement.
WHAT WE KNOW ABOUT SLK
The exact etiology and pathophysiology of SLK are not fully understood. Changes in the normal eyelid-globe mechanical interactions may all contribute to some of the findings noted. These changes can be secondary to the retracted upper eyelid exerting pressure on the superior limbus, lid retraction causing altered blinking, and changes in tear film production.
Differentiating conjunctivochalasis and SLK
Keep in mind that superior conjunctivochalasis may present with SLK-like findings clinically.1 Further, one study2 reported the association of conjunctivochalasis with SLK, although we do not fully understand the exact pathologic association between the two clinical entities.
SLK has redundant superior bulbar conjunctiva that may be secondary to the mechanical lid-rubbing friction theory as a cause of SLK.3 Some evidence for a mechanical theory of etiology for SLK also comes from the detection of snake-like chromatins reflecting mechanical stress within the nucleus of involved ocular surface cells4 and up-regulation of tenascin and transforming growth factor (TGF)-ß2 in the conjunctiva and integrin ß1 expression in the suprabasal region of the epithelium.1,4,5
Other investigators1,7 have reported cases with superior conjunctivochalasis to have SLK-like findings. These patients had all the classic findings of conjunctivochalasis, including poor adhesion between conjunctiva and sclera secondary to Tenon degradation, formation of a wrinkled conjunctiva on pressing the upper lid against the upper bulbar conjunctiva during slit-lamp examination, and the formation of “tenting” phenomenon when forceps were used during surgery.1 Some of these patients had ocular pain and photophobia that may be associated with SLK and absent in conjunctivochalasis.
Hence, the two disease entities, SLK and superior conjunctivochalasis, may coexist and be part of an extended disease spectrum.
Systemic involvement
Systemically, the patient may have thyroid abnormalities6–10 that require investigation as well. Most cases of SLK often go undiagnosed and under treated because the symptoms are nonspecific and the clinical evaluation inaccurate. Optimizing the diagnosis, ocular care and management dictates the need for a highly disciplined approach to the ocular surface evaluation using the biomicroscope.
SLK is an under-diagnosed and under treated member of the ocular surface disease family. SLK appears to have an association with superior conjunctivochalasis, and signs and symptoms of both diseases may exist concomitantly, so you must take care to distinguish one from the other. Critically, the upper eyelid masks everything beneath it, including SLK, so lift the lid or you’ll miss the diagnosis of SLK. OM
| Treatment approaches for SLK |
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Medical managementInitial management of SLK involves topical artificial tears and lubricating ophthalmic ointments, with or without topical corticosteroid drops. Additionally, a decrease in the upper tear meniscus has been detected in patients with SLK, so upper punctal occlusion may be indicated in appropriate cases.11 Other medical treatments include pressure patching, sliver nitrate solution, cyclosporine A, vitamin A preparations and autologous serum-derived drops. Botulinum injection of the overlying muscle of Riolan has been tried as a method of SLK treatment with some success. Supratarsal triamcinolone injection has been beneficial in some SLK patients. As a continued reminder, silver nitrate sticks should never be used on the eye because they can cause severe caustic injury. Bandage soft contact lenses can be helpful in relieving some of the symptoms of idiopathic SLK of Theodore. In patients with contact lens-related SLK, temporary discontinuation of the contact lens wear may be beneficial. In patients with thyroid-related proptosis, reversal of proptosis often provides symptomatic relief from SLK. Surgical treatmentsBecause medical treatment usually provides only temporary relief of symptoms, surgical intervention may often become necessary. Surgical approaches include conjunctival recession or resection,12 direct superior bulbar conjunctival cauterization,13 liquid nitrogen double freeze-thaw cycle14 and conjunctival resection with amniotic membrane transplantation.12 Intraoperative rose Bengal staining of the superior bulbar conjunctiva delineates the area of conjunctiva to be resected. |
REFERENCES
1. Kheirkhah A, Casas V, Esquenazi S, et al. New surgical approach for superior conjunctivochalasis. Cornea. 2007;26:685-691.
2. Yokoi N, Komuro A, Maruyama K, Tsuzuki M, Miyajima S, Kinoshita S, et al. New surgical treatment for superior limbic keratoconjunctivitis and its association with conjunctivochalasis. Am J Ophthalmol. 2003;135:303-308.
3. Wright P. Superior limbic keratoconjunctivitis. Trans Ophthalmol Soc UK. 1972;92:555-560.
4. Knop E, Reale E. Fine structure and significance of snakelike chromatin in conjunctival epithelial cells. Invest Ophthalmol Vis Sci. 1994;35:711-719.
5. Matsuda A, Tagawa Y, Matsuda H. TGF-beta2, tenascin, and integrin beta1 expression in superior limbic keratoconjunctivitis. Jpn J Ophthalmol. 1999;43:251-256.
6. Kadrmas EF, Bartley GB. Superior limbic keratoconjunctivitis. A prognostic sign for severe Graves ophthalmopathy. Ophthalmology. 1995;102:1472-1475.
7. Bartley GB. The epidemiologic characteristics and clinical course of ophthalmopathy associated with autoimmune thyroid disease in Olmsted County, Minnesota. Trans Am Ophthalmol Soc. 1994;92:477-588.
8. Wilson FM, Ostler HB. Superior limbic keratoconjunctivitis. Int Ophthalmol Clin. 1986;26:99-112.
9. Theodore FH. Comments on findings of elevated protein-bound iodine in superior limbic keratoconjunctivitis: I. Arch Ophthalmol. 1968;79:508.
10. Cher I. Clinical features of superior limbic keratoconjunctivitis in Australia. A probable association with thyrotoxicosis. Arch Ophthalmol. 1969;82:580-586.
11. Yang HY, Fujishima H, Toda I, et al. Lacrimal punctal occlusion for the treatment of superior limbic keratoconjunctivitis. Am J Ophthalmol. 1997;124:80-87.
12. Gris O, Plazas A, Lerma E, Güell JL, Pelegrín L, Elíes D. Conjunctival resection with and without amniotic membrane graft for the treatment of superior limbic keratoconjunctivitis. Cornea. 2010;29:1025-1030.
13. Udell IJ, Kenyon KR, Sawa M, Dohlman CH. Treatment of superior limbic keratoconjunctivitis by thermocauterization of the superior bulbar conjunctiva. Ophthalmology 1986;93:162-166.
14. Fraunfelder FW. Liquid nitrogen cryotherapy of superior limbic keratoconjunctivitis. Am J Ophthalmol. 2009;147:234-238.
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