RESUMEN
PURPOSE: To evaluate the efficacy of transconjunctival botulinum toxin type A (BTX-A) in the treatment of upper eyelid retraction in the active inflammatory phase of dysthyroid orbitopathy, establish the ideal dose, and evaluate side effects. METHODS: This is a comparative, prospective study in patients with thyroid orbitopathy, conducted at the Conde Ophthalmology Institute in Valenciana, Mexico. The patients included had dysthyroid orbitopathy in the inflammatory phase, and they were treated with subconjunctival injection of botulinum toxin type A (BTX-A) in the upper eyelid. Five units (group 1) and ten units (group 2) of BTX-A, in a single subconjunctival dose were applied to the non-dominant eye. We evaluated visual acuity, margin-to-reflex distance (RPM1), crease height, ocular motility, diplopia and keratitis, before and after administration of the toxin. The patients were followed at one, 4 and 16 weeks, with the Student t-test as a statistical analysis. RESULTS: At week 4, 15 patients (100%) showed a reduced margin to reflex distance. The mean result for group 1 was -1.75mm (range -1 to -2.5mm) and group 2 was -2mm (range -1 to -4mm). Statistically significant differences were seen between pre-treatment and week 4 in both groups, but no differences between doses. Complete improvement of keratitis and lagophthalmos was observed in 5 and 2 patients, respectively. Visual acuity, ocular motility and crease height did not change in 93% of the patients. One patient (group 1) exhibited complete ptosis and vertical diplopia, which resolved spontaneously at week 6. CONCLUSION: Transconjunctival BTX-A application is safe and effective for the treatment of eyelid retraction in dysthyroid orbitopathy. No difference was found between doses. No severe side effects were reported.
