Abstract
Purpose :
Dorzolamide-timolol drops decrease the production of aqueous humor, which may increase medication retention and subsequent duration of intravitreal injections. This study investigated whether topical dorzolamide-timolol use decreased frequency between injections of patients who received combination therapy of (dexamethasone implants and anti-VEGF agents) compared to patients who did not receive the drops.
Methods :
This retrospective study reviewed patients receiving combination therapy to treat RVOs from 2009 to 2016. Duration in days between combination therapy treatments was recorded for patients who were on topical dorzolamide-timolol and those who were not. The groups were then subdivided based on which anti-VEGF agent they received (ranibizumab or aflibercept). Independent 2-sample t-tests were used for statistical analysis.
Results :
Fifteen eyes with 30 injection intervals were assessed in the dorzolamide-timolol group, versus 66 eyes with 242 injection intervals in the control group. A previous study demonstrated that the mean interval between injections in this patient population was 126 days.1 There was no statistically significant difference in the days between cycles of combination therapy for those using the drops (129.07 ± 35.08) and control (137.10 ± 35.08) (p=0.36). Subgroup median analysis based on the anti-VEGF agent used showed no significant difference in number of days between injections for those with (136.32 ± 58.02) and without drops (136.32 ± 58.02) in the aflibercept group (p=1.00) and those with (109.13 ± 56.01) and without drops (137.13 ± 56.01) in the ranibizumab group (p=.18).
Conclusions :
The use of topical dorzolamide-timolol in patients who received combination therapy for RVOs did not significantly prolong the time interval between injections in patients. An article in JAMA Ophthalmology 2016 states that topical dorzolamide-timolol “may reduce central subfield thickness and subretinal fluid in eyes with persistent exudation despite consistent, fixed-interval intravitreous anti-VEGF treatment for neovascular AMD.”2 Our current study does not support these results in patients treated RVO.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.