Intravitreal dexamethasone implant: Effective in both vitrectomized and non-vitrectomized eyes

Intravitreal dexamethasone still seems to be effective for patients with diabetic macular edema have undergone a previous vitrectomy.

Kin-woo Kwon, MD, PhD, and Young-Gun Park, MD, PhD, reported that the intravitreal dexamethasone pharmacokinetics and pharmacodynamics differ between eyes that have been vitrectomized and those that have not. However, intravitreal dexamethasone still seems to be effective for patients with diabetic macular edema (DME) have undergone a previous vitrectomy. Drs. Kwon and Park are from, respectively, the Department of Ophthalmology, St. Vincent’s Hospital, College of Medicine, The Catholic University of Korea, and the Department of Ophthalmology, Seoul St. Mary’s Hospital, College of Medicine, Catholic University of Korea, both in Seoul, Korea.

The investigators undertook a retrospective observational study1 to determine the clinical outcomes of intravitreal dexamethasone implantation in eyes of patients with DME who had been treated with a previous vitrectomy.

In this study, Drs. Kwon and Park recorded the following parameters: central subfield thickness (CST), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) up to 12 months after the dexamethasone implantation. The duration of the implant’s action, IOP trends, and the prevalence of ocular hypertension (OHTN) after the first treatment with the implant were compared in the eyes that had and had not undergone a vitrectomy. Also compared were the CST, BCVA, number of treatments, and prevalence of OHTN between the two groups after 12 months, they recounted.

Results of the analysis

The CST, BCVA, and prevalence of OHTN during treatment did not differ between the groups. The investigators did find that the duration of action of the first dexamethasone treatment was significantly shorter in eyes that had undergone a vitrectomy. As a results those eyes needed more treatments during the 12-month follow-up period.

They also found another difference, that is, the highest average IOP occurred 2 months after the first dexamethasone treatment in the group that had not undergone a vitrectomy but the highest average IOP was seen at 1 month after the first dexamethasone treatment in the group treated with vitrectomy.

These findings led the authors to suggest that the pharmacokinetics and pharmacodynamics of the intravitreal dexamethasone implant differ between vitrectomized and non-vitrectomized eyes. However, considering the relatively long-lasting effectiveness of the treatment and the good clinical results, consecutive intravitreal dexamethasone treatments may be beneficial for patients with DME patients who had undergone a previous vitrectomy.

Reference

1. Kwon J-W, Park Y-G. Clinical features of intravitreal dexamethasone implantation in vitrectomized eyes of patients with diabetic macular edema. Retina. 2021; doi: 10.1097/IAE.0000000000003380