Purpose. To describe the changes seen with the confocal microscope in Thygeson's superficial punctate keratopathy (TSPK).
Methods. Confocal microscopy was performed on six patients with TSPK presenting to Manchester Royal Eye Hospital from October 1999 to June 2001. Both eyes were examined including the normal fellow eyes of two patients with unilateral TSPK. Images were compared with age-matched controls.
Results. Irregular nerve fibers, masked by considerable haze, were seen in the subepithelial nerve plexus immediately above Bowman's membrane in TSPK. Generalized haze was also present in the anterior stroma along with areas of high reflectivity, microdots, and reflective bodies. Keratocytes had highly reflective nuclei and cell bodies of irregular size, orientation, and shape. The changes were related to the duration of TSPK, were not seen in normal fellow eyes, and were also present in areas without lesions.
Conclusion. Confocal imaging of TSPK demonstrated considerable abnormalities in the subepithelial nerve plexus, Bowman's membrane, and the anterior stroma that were related to disease duration. Similar changes have been reported in a variety of corneal diseases and following laser corneal surgery. Recent evidence has supported interactions between the epithelium and Bowman's membrane and the anterior stroma in corneal disease and after laser corneal surgery. We speculate that such interactions may have a role in TSPK.
Thygeson's superficial punctate keratopathy (TSPK) is a disease of unknown etiology. 1–3 Patients present with irritation, tearing, photophobia, and visual disturbance. 1,4,5 It is most commonly bilateral and has a chronic course with exacerbations and remissions. 1,3–6 To date, no systemic conditions have been associated with TSPK. 5
On slit-lamp biomicroscopy, elevated, coarsely granular opacities that stain with fluorescein are seen in the corneal epithelium. 1,5,7 The opacities typically lie close to the visual axis, can change their location with time, and may be present when the patient is asymptomatic. 1,7,8 Under higher magnification, numerous granular dots in oval or stellate patterns are visible. 9 Subepithelial opacity beneath the lesions has also been reported. 10 The bulbar conjunctiva is usually white or may have a very minimal flush during exacerbations. 1 Corneal and conjunctival sensitivity are normal. 6
Topical steroid therapy can induce remission but may prolong the course of TSPK. 1,3–5,11 Patching and therapeutic contact lens (CL) provide symptom relief, CL may also improve vision. 4–6,8 Recently, cyclosporin A has been used to treat TSPK. 2 Phototherapeutic keratectomy (PTK), in a single case, eliminated the lesions in the ablated area. 8
Information on histopathology is limited as corneal grafting is generally not required. Scraping of the lesions has shown slightly abnormal epithelial cells with vacuolated cytoplasm. 1 Confocal microscopy allows in vivo assessment of corneal pathology and is therefore ideal for TSPK; its use in this study is described.