Retrospective Study Shows Potential of Dexamethasone Implant for Treatment-Resistant Diabetic Macular Edema

A study exploring the use of intravitreal dexamethasone as a treatment option for diabetic macular edema (DME) in patients who cannot use or benefit from anti-vascular endothelial growth factor (anti-VEGF) therapy found significant improvements supporting its potential as a personalized precataract surgical approach for DME management. 

Despite advancements in ophthalmology, treating DME remains challenging due to its variable response to treatment and the diverse profiles of affected patients. While laser photocoagulation used to be the primary treatment, new pharmacological therapies, such as anti-VEGF agents, have revolutionized DME management. However, for patients who cannot use or benefit from anti-VEGF therapy, alternative options like intravitreal corticosteroid therapy offer promise. The dexamethasone (Ozurdex) implant is approved and conveniently releases medication over 6 months.  

The retrospective study aims to explore the use of intravitreal dexamethasone for patients with treatment-resistant DME who can't use anti-VEGF therapy administered a month before cataract surgery.  

The study was conducted at a tertiary eye care center in India from December 2021 to April 2023. The study included patients aged 18 years or older with controlled diabetes and clinically significant cataracts, along with untreated diabetic macular edema. Patients also had a contraindication for intravitreal anti-VEGF therapy. Exclusion criteria included a history of ocular hypertension/glaucoma, prior ocular surgery/laser therapy, or other retinal pathologies.  

Patients received intravitreal DEX under topical anesthesia, followed by cataract surgery one month later. Follow-up visits were scheduled at various intervals to assess visual acuity, intraocular pressure, and other measures. The primary outcomes measured were changes in visual acuity and central macular thickness. Adverse events and changes in intraocular pressure were also recorded. Statistical analysis was performed using SPSS 23.0, with P values less than 0.05 considered statistically significant. 

The average age of the 20 participants was 57.2 years old. Most participants were male, accounting for 75% of the total. According to the early treatment of diabetic retinopathy study (ETDRS) criteria, 75% of the eyes had moderate nonproliferative DR (NPDR), 15% had severe NPDR, and 10% had proliferative diabetic retinopathy (PDR). A slightly higher percentage of patients had a history of myocardial infarction (55%), while the rest had a history of a stroke (45%) within the past 3 months.  

At the beginning of the study, the mean best-corrected visual acuity (BCVA) was 0.74 logMAR. However, after receiving DEX treatment, there was a significant improvement in visual acuity at days 30, 90, and 180. Furthermore, there was a decrease in retinal thickness at days 30, 90, and 180 compared to the baseline. Three eyes underwent pan-retinal photocoagulation at day 60, and 5 eyes experienced a recurrence of DME at the 90-day mark and received a second administration of DEX implant. 

In terms of safety, the mean intraocular pressure (IOP) increased significantly after DEX therapy, but none of the participants' eyes required topical anti-glaucoma medication or surgery for elevated IOP during the 180-day study period. Additionally, there were no reported ocular or systemic adverse events throughout the study. 

The unexpected improvements in visual acuity were notable despite the presence of cataracts. This sustained improvement is significant as it reduces the need for frequent interventions and enhances the quality of life for patients. Additionally, the reduction in macular thickness, which lasted up to day 180, is equally important and demonstrates the effectiveness of the DEX implant in reducing fluid accumulation and restoring retinal morphology. Furthermore, the study found a lower recurrence of ocular edema compared to similar studies with treatment-resistant cases, indicating the favorable safety profile of DEX. These findings support the use of DEX in treatment-naive DME patients with contraindications to anti-VEGF therapy and highlight its potential benefits as a pre-cataract surgical approach. 

“The study’s findings provide insights into improving visual acuity and reducing macular thickness, along with manageable IOP changes,” said researchers. “This personalized approach is a valuable addition to DME management, especially for complex medical cases, warranting further research and consideration for clinical practice.”  

Reference 

Chakraborty S, Ganguly S, Sheth JU. Role of intravitreal dexamethasone implant in the management of treatment-naive diabetic macular edema: a pre-cataract surgical approach for patients with systemic contraindications to anti-VEGF therapy. Clin Ophthalmol. 2024;18:227-233. doi:10.2147/OPTH.S449250