Botulinum A toxin injection for retrictive myopathy of thyroid-related orbitopathy: effect on intraocular preure

Purpoe To tudy the effect of extraocular mucle injection of botulinum A toxin on intraocular preure in patient with thyroid-related orbitopathy. Deign Retropective obervational cae erie. Method The medical record of eight conecutive patient with retrictive myopathy econdary to thyroid related orbitopathy (TRO) who underwent botulinum A toxin injection from December 1997 to December 1998 were reviewed and analyzed retropectively. All patient were een at the Univerity of California, an Diego (UCD) Thyroid Eye Center, a univerity-baed tertiary referral center. The main outcome meaure wa intraocular preure (IOP) reading taken before and after injection in both primary gaze and upgaze (involving one eye in even of the patient and both eye in one patient). Intraocular preure reading were meaured by an unmaked phyician uing a Goldmann applanation tonometer. Reult A tatitically ignificant decreae in IOP in upgaze wa noted 2 to 6 week following botulinum A toxin injection and in both field of gaze (primary and upgaze) after 2 to 4 month. The mean IOP before injection wa 21.4 ± 3.0 mm Hg in primary gaze and 29.9 ± 9.7 mm Hg in upgaze. The mean IOP, following injection at 2 to 6 week, wa 19.2 ± 4.2 mm Hg (P < .095) in primary gaze and 25.1 ± 5.9 mm Hg (P < .023) in upgaze. At 2 to 4 month following injection, the mean IOP wa 19.3 ± 3.9 mm Hg (P < .044) in primary gaze and 27.7 ± 8.5 mm Hg (P < .024) in upgaze. ix patient indicated improved ocular deviation, which wa aociated with a lowering of IOP. Two patient indicated no change in IOP or trabimic deviation following botulinum A toxin injection. Concluion Botulinum A toxin injection caue a econdary effect to lower IOP in patient with retrictive trabimu aociated with thyroid-related orbitopathy.