Effects of radiation therapy on the meibomian glands and dry eye in patients with ocular adnexal mucosa-associated lymphoid tissue lymphoma

BACKGROUND: Radiation therapy (RT) is the treatment of choice in patients with low-grade ocular adenexal mucosa-associated lymphoid tissue lymphoma (OAML) and many of them experience post-RT dry eye with varying severity. The purpose of the present study was to investigate ocular effects of RT on meibomian glands and dry eye by directly visualizing structural changes. Secondly, we focused on the comparison of two groups of patients according to tumor location and radiation technique. METHODS: Sixty-four eyes with OAML of conjunctiva, orbit, lacrimal gland, or lacrimal sac were grouped into conjunctival lymphoma and “orbital-type” lymphoma (i.e., orbit, lacrimal gland, and lacrimal sac). Subjects were investigated for morphological changes in meibomian glands by meiboscore grading system. Radiation technique was examined and Ocular Surface Disease Index (OSDI) questionnaire, Schirmer’s test, tear film break-up time (TBUT), slit lamp examination of corneal surface and lid margin abnormality were conducted before and after RT. RESULTS: The increase in meiboscore was statistically significant over time after RT in both groups (P < 0.001). The extent of increase in meiboscore was significantly greater in the “orbital-type” lymphoma group than in the conjunctival lymphoma group (P < 0.001). The changes in OSDI, TBUT, corneal fluorescein staining score and lid margin abnormality score after RT were significantly different across two groups (P = 0.042, 0.001, 0.035 and 0.001, respectively). Schirmer’s value decreased after RT in both groups. Dry eye symptoms were most severe right after RT in both groups, but a gradual resolution was noted in most patients with conjunctival lymphoma, whereas symptoms persisted in “orbital-type” lymphoma patients. The OSDI score and corneal fluorescein staining score were positively correlated with meiboscore in “orbital-type” patients at post-RT 6 months (r = 0.43, P = 0.04; r = 0.39, P = 0.03, respectively). CONCLUSIONS: Patients with OAML had different degrees of morphological changes in meibomian glands according to tumor location and radiation technique. “Orbital-type” lymphoma patients are more likely to experience severe injury to meibomian glands, which eventually leads to persistent dry eye. Patients with “orbital-type” lymphoma should be well informed of post-RT damage on meibomian glands and persistent dry eye.