Effect of systemic steroid and orbital radiotherapy on dry eye parameters in Thyroid Associated Orbitopathy (TAO)

Abstract

Purpose : More than two-third of the patients with TAO suffer from various degree of dry eye (DE). While pulse intravenous glucocorticoid (GC) therapy is the first-line treatment in active or progressive TAO, additional orbital radiotherapy (OR) was shown to improve diplopia and lower recurrence. However, potential effect of GC and OR on DE remains unknown. We evaluate their effects on dry eye parameters in TAO patients.

Methods : In a prospective cohort, patients were managed either conservatively (Group A), with GC (Group B) or GC and OR according to the clinical activity score (CAS) and degree of diplopia, assessed by the same oculoplastic surgeon. GC was given as 12 weekly pulse methyl-prednisolone infusion according to the EUGOGO protocol. OR were given in 20 Gy fractionated over 10 days. DE was evaluated by Ocular Surface Disease Index (OSDI), Tear Breakup Time (TBUT), and corneal staining at baseline, 3 and 6 months after treatment. Parameters were compared between time-points and treatment groups.

Results : Mean age of patients in Group A (n=86) was 50±15, Group B (n=20) 48±14 and Group C (n=136) 59±11 (p<0.05). More male patients were in Group C (30%, 35% and 50% respectively, p < 0.05). CAS was significantly higher in Group B (3.8±0.2) and C (2.4±1.6) compared to Group A (1.4±1.2) (p<0.01). Baseline DE was evident in 87% of patients when defined by OSDI score of ≥13, 51% were severe when defined by OSDI score of ≥33. OSDI and degree of corneal staining were comparable between groups at baseline (p > 0.05). Significant improvements were found at 6 months in Group B and C compared to baseline (both p <0.05) but not in Group A. Group B showed significant improvement in TBUT at 3 months compared to Group A and C (p >0.01) while Group C showed significant improvement in OSDI at 6 months compared to Group A (p<0.05).

Conclusions : Dry eye is highly prevalent in this cohort and improved significantly after GC with or without RT compared to baseline. Additional use of OR may have negative impact on TBUT at 3 months compared to those treated by GC alone, but no difference was found at 6 months or on OSDI. Patients should be advised on potential short-term worsening of DE when receiving additional OR for active or progressive TAO.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.