title: Safety of intravitreal triamcinolone acetonide: an electrophysiologic and histopathological study in rabbits.
abstract: OBJECTIVE
  To evaluate the retinal safety of various doses of intravitreal triamcinolone acetonide (TA) in rabbits.
  
  
  METHODS
  Thirty New Zealand albino rabbits were divided into five groups (six animals each). In group 1 (control group), each animal received a single intravitreal injection of 0.1mL phosphate buffered saline. In groups 2, 3, 4 and 5, each rabbit received a single intravitreal injection of 4, 8, 16 and 32mg of TA, respectively. Each dose was contained in 0.1mL phosphate buffered saline. Clinical ocular examinations were performed before the injection and on the 1st, 3rd, 10th and 17th post-injection days. A standard dark adapted electroretinogram (ERG) was obtained before injection and on the 3rd, 10th and 17th post-injection days. After 17d, animals were sacrificed and their eyes prepared for pathological examination.
  
  
  RESULTS
  By monitoring ERG as a functional index for the retina, intravitreal injection of 4mg TA showed no significant ERG changes. At doses of 8, 16 and 32, hyper-abnormal responses in a- and b- waves of ERG were detected on the 3rd post-injection day. These changes gradually returned back to normal limits after 17d. Histopathological examination of the retina of all animals showed no pathological changes.
  
  
  CONCLUSIONS
  High doses of intravitreal TA seemed to have enhancing effects on the retinal function with gradual return to normal limits with no pathological changes detected in examined eyes.
authors.affiliation: Department of Ophthalmology, Memorial Institute of Ophthalmology, 3-Al-Ahram Street, Giza, Cairo 12511, Egypt.
authors.forename: Laila Hassan M
authors.initials: LH
authors.lastname: El-Shazly
authors.affiliation: Department of Physiology, Research Institute of Ophthalmology, 2-Al-Ahram Street, Giza, Cairo 12511, Egypt.
authors.forename: Amal Ahmad
authors.initials: AA
authors.lastname: El-Gohary
authors.affiliation: Department of Pharmacology, Research Institute of Ophthalmology, 2-Al-Ahram Street, Giza, Cairo 12511, Egypt.
authors.forename: Ghada Ghanem
authors.initials: GG
authors.lastname: El-Hossary
keywords: electroretinogram; intravitreal injection; triamcinolone acetonide