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Updated: May 18, 2026

Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs
Published on: July 23, 2016
Repeated intravitreal dexamethasone implant (Ozurdex®) for retinal vein occlusion
Lea Querques1, Giuseppe Querques, Rosangela Lattanzio
1Department of Ophthalmology, University Scientific Institute San Raffaele, Milan, Italy.
Purpose:
To evaluate the effects of repeated intravitreal dexamethasone implant (IDI) (Ozurdex®) in eyes with macular edema (ME) due to retinal vein occlusion (RVO).
Methods:
We reviewed the charts of patients with RVO-related ME, who received repeated Ozurdex IDI (0.7 mg) on an 'as-needed' basis. Main outcome measures included changes in best-corrected visual acuity (BCVA), central macular thickness (CMT), retreatment interval, and incidence of side effects.
Results:
A total of 33 eyes were included for analysis. Retreatment with Ozurdex was judged necessary after 4.7 ± 1.1 months from the first IDI (1st IDI) and 5.1 ± 1.5 months from the second IDI (2nd IDI). Baseline BCVA was 0.65 ± 0.43 logMAR; it significantly improved to 0.50 ± 0.42 logMAR after 1.4 ± 0.7 months from the 1st IDI (peaking efficacy) (p < 0.001) and to 0.48 ± 0.44 logMAR after 1.8 ± 0.8 months from the 2nd IDI (peaking efficacy) (p < 0.001). CMT decreased from 636 ± 217 µm (baseline) to 300 ± 114 µm, 1.4 ± 0.7 months after the 1st IDI (p < 0.001), and to 298 ± 91 µm, 1.8 ± 0.8 months after the 2nd IDI (p < 0.001). A rebound effect was recorded in 7 eyes after the 1st IDI (mean 168 ± 158 µm) and in 4 eyes after the 2nd IDI (mean 215 ± 199 µm). All eyes with a rebound effect improved again after a 2nd intravitreal Ozurdex injection. No serious adverse events were observed; 12 eyes developed a transient IOP increase, and cataracts were extracted in 2 eyes.
Conclusion:
Repeated intravitreal Ozurdex on an 'as-needed' basis, with a retreatment interval <6 months, may produce long-term clinically meaningful benefits in the treatment of ME due to RVO, without other significant side effects than expected after intraocular corticosteroid treatment.
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