Related Experiment Video
Updated: Nov 24, 2025
Use of Rabbit Eyes in Pharmacokinetic Studies of Intraocular Drugs
Published on: July 23, 2016
The efficacy of dexamethasone implants following anti-VEGF failure for macular oedema in retinal vein occlusion
Timothy E Yap1,2, Salman Husein2, Juan Antonio Miralles de Imperial-Ollero2,3
1Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK.
Purpose:
To investigate the efficacy of intravitreal dexamethasone implants (DEX) after anti-VEGF failure in retinal vein occlusion macular oedema.
Methods:
Retrospective cohort study of DEX implant (0.7 mg) given after anti-VEGF 'failure'. Switch to DEX occurred if a ⩽ +5 ETDRS letter gain and ⩽20% reduction in central subfield thickness was present following ⩾6 consecutive anti-VEGF injections. The primary endpoint was VA change 30 days after DEX. Secondary outcomes were peak VA change, VA change at monthly timepoints, percentage achieving 15-letter gain, central subfield thickness (CST) and intraocular pressure (IOP).
Results:
Sixty-two injections in 62 patients associated with 26% central retinal vein occlusion (CRVO) and 74% branch retinal vein occlusion (BRVO) were eligible. There was a modest, significant improvement in mean VA change at 30 days compared to baseline (+6 letters, 95% CI +2.2 to +9.1 letters, p < 0.01). DEX implant significantly improved mean peak VA change compared to preceding anti-VEGF by +18.1 letters in CRVO (p = 0.002) and +13.2 letters in BRVO (p < 0.0001). IOP peaked between 30 and 60 days following injection, with 31% of CRVO and 11% of BRVO patients experiencing an IOP ⩾ 25 mmHg.
Conclusion:
DEX implant provides useful rescue therapy in cases of anti-VEGF 'failure' for macular oedema following retinal vein occlusion, resulting in improved functional outcomes at 30 days.
