Hypotony Rates Higher With Implant Than Intravitreal Macular Edema Treatment

The rate of ocular hypotony, which causes transient visual impairment, is higher in vitrectomized eyes that received a dexamethasone (DEX) implant compared with those given intravitreal triamcinolone for macular edema, according to research published in Ophthalmology Retina.

Researchers conducted a retrospective, comparative case series to evaluate the rate of complications in eyes that received a DEX implant or intravitreal triamcinolone to treat post-vitrectomy macular edema. 

The team used medical records of patients who received intravitreal DEX (0.7 mg) or triamcinolone (2 mg) for post-vitrectomy macular edema between July 2014 and December 2021 and had a minimum follow-up duration of 3 months. They evaluated the types and rates of complications, including ocular hypotony (intraocular pressure [IOP] <6 mm Hg) and ocular hypertension (IOP >24 mm Hg).

A total of 148 eyes of 147 patients were included in the study. The DEX group included 75 eyes of 75 patients (mean age, 68.9±11.4 years; 57% men and 43% women) and had a mean follow up duration of 2.7±1.7 years. The triamcinolone group included 73 eyes of 72 patients (mean age, 70.6±12.9; 54% women and 46% women) and had a mean follow-up duration of 2.4±1.6 years. 

The researchers found the rate of transient ocular hypotony, both per eye and per injection, was significantly higher in the DEX group compared with the triamcinolone group (13% vs 3% of eyes; P =.039 and 7% vs 0.8% of injections P <.001). They observed a significant decrease in mean visual acuity at the time of ocular hypotony from 1.08±0.65 to 1.48±0.54 logMAR (P =.031) and a return to the mean preinjection level (1.19±0.55 logMAR; P =.688) following resolution of the hypotony after a median of 12 days. 

They report that the incidences of ocular hypertension, vitreous hemorrhage, and rhegmatogenous retinal detachment are not significantly different between the groups. 

“The visual acuity significantly improved throughout the study period after DEX treatment, while the visual acuity significantly improved by 6 months but did not significantly improve after 6 months following IVT treatment,” according to the report. “The mean CFT significantly improved throughout the study period in both the DEX and IVT groups. However, the rate of complications was more common after DEX.”

Limitations of the study include the retrospective design, lack of a protocol for re-injections, differing underlying pathologies, numbers of injections and follow-up durations, subconjunctival lidocaine injection prior to dexamethasone injection in some eyes, potential differences in injection techniques, and inability to evaluate the injection sites and their potential association with complications. 

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.