Purpose: To evaluate the tear function and ocular surface alterations in patients with primary CIN before and after treatment with topical mitomycin (MMC).
Patients and methods: We describe seven patients with unilateral CIN treated with 0.04% topical MMC three times daily until full eradication of the lesion. The patients underwent tear and ocular surface examinations including Cochet-Bonnet corneal sensitivity measurements, tear film break-up time (BUT), Schirmer test, and Rose-Bengal staining before, at the time of resolution of the CIN, and at the final follow-up. Conjunctival impression cytology was performed before treatment and at the last visit.
Results: The mean pretreatment corneal sensitivity was 30.3 +/- 7.4 mm and improved to 55 +/- 5 mm at the final visit (P < 0.05). There were no aqueous-deficient eyes. The BUT values and Rose-Bengal staining scores also showed significant improvement at the last follow-up compared with the pretreatment values (P < 0.05). Initial impression cytology specimens showed goblet cell loss, higher grades of squamous metaplasia, areas of isolated keratinized, binucleated, and actively mitotic disfigured epithelial cells in all patients. The mean goblet cell density and squamous metaplasia grade were observed to improve significantly at the last visit (P < 0.05). MMC-induced cytologic changes were seen to persist long after cessation of treatment in some patients. All eyes remained free of recurrence and complications during the follow-up period.
Conclusion: We found 0.04% topical MMC treatment tid until full eradication to be effective in the management of CIN. The ocular surface disease of CIN was characterized by disturbance of tear film stability, goblet cell loss, and increased squamous metaplasia in all patients. Impression cytology proved useful in attaining the diagnosis of CIN, evaluating the effect of treatment, and showing MMC-related long-term changes on the ocular surface.