The etiology of Thygeson superficial punctate keratitis (SPK) is unknown. Although many of the clinical features resemble those of a viral infection of the corneal epithelium, attempts to confirm viral particles by electron microscopy or culture have been unsuccessful. No inflammatory cells are evident. The rapid response of the lesions to corticosteroid therapy suggests that Thygeson keratitis is largely immunopathogenically derived.
Connell PP, O’Reilly J, Coughlan S, Collum LM, Power WJ. The role of common viral ocular pathogens in Thygeson’s superficial punctate keratitis. Br J Ophthalmol. 2007;91(8): 1038–1041.
This condition, first reported by Thygeson in 1950, is characterized by recurrent episodes of tearing, foreign-body sensation, photophobia, and reduced vision. It affects children to older adults and is typically bilateral, although it may develop initially in 1 eye or may be markedly asymmetric in some cases. The hallmark finding is multiple (up to 40 but as few as 2–3) slightly elevated corneal epithelial lesions with “negative staining,” which are noted during exacerbations. The epithelial lesions are round or oval conglomerates of gray, granular, or “crumblike” opacities associated with minimal conjunctival reaction, in contrast to adenoviral keratoconjunctivitis. High magnification reveals each opacity to be a cluster of multiple smaller pinpoint opacities (Fig 11-15). A characteristic feature is the waxing and waning appearance of individual epithelial opacities, which change in location and number over time. The greatest density of these lesions is typically found in the central cornea. The raised punctate epithelial lesions themselves stain faintly with fluorescein and rose bengal.
No conjunctival inflammatory reaction is noted during exacerbations, but occasionally patients have mild bulbar conjunctival hyperemia. In rare cases, a mild subepithelial opacity may develop under the epithelial lesion—more commonly in patients who have received topical antiviral therapy. The important facet of this condition is that the patient’s symptoms may far exceed the apparent signs; frequently, patients report severe photophobia and foreign-body sensation in the setting of only a few central epithelial lesions.
A, Thygeson superficial punctate keratitis. B, At higher magnification, each lesion is seen to consist of raised, granular opacities.
Supportive therapy with artificial tears is often adequate in mild cases. Treatment alternatives for persistently symptomatic cases include low-dose topical corticosteroids and bandage contact lenses. Currently, antiviral therapy is not the standard of care, as there are no firm data to associate this condition with an active replicative viral infection.
If a topical corticosteroid is prescribed, a very mild preparation may be effective (eg, fluorometholone 0.1%). Because the lesions are quite responsive to corticosteroids, treatment will hasten their resolution, but they frequently recur in the same or different locations on the cornea after the topical corticosteroids are stopped. Overall, corticosteroid use should be minimized in these cases and monitored closely because of their associated risks. Topical cyclosporine or tacrolimus ophthalmic preparations may also be effective in causing regression of the lesions. It is important to remember to treat the symptoms, not the clinical findings, in patients with Thygeson SPK.
Marquezan MC, Nascimento H, Vieira LA, et al. Effect of topical tacrolimus in the treatment of Thygeson’s superficial punctate keratitis. Am J Ophthalmol. 2015;160(4):663–668.
Vieira AC, Schwab IR. Superficial punctate keratitis of Thygeson. In: Mannis MJ, Holland EJ, eds. Cornea. Vol 1. 4th ed. Philadelphia: Elsevier; 2017:1030–1034.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.