Patients with Macular Edema Benefit From Dexamethasone Implant Prior to Cataract Surgery

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Patients with macular edema due to diabetes or retinal vein occlusion (RVO) may benefit from intravitreal dexamethasone (DEX) implants prior to cataract surgery, according to new research.¹

The real-world analysis showed intraocular pressure (IOP) increased pre-surgery following baseline injection of the DEX implant, but returned to baseline at 6 months post-surgery, with no additional IOP-lowering drugs required.

“The findings of this and earlier studies suggest that DEX implants could be a potential therapy for diabetic patients with post-surgical macular edema,” wrote the investigative team, led by Shu-Chun Kuo, from the department of ophthalmology at National Cheng Kung University Hospital.

Patients with diabetes and RVO have a greater risk of combined cataracts and macular edema and make up a growing population of patients receiving cataract surgery. Cataract surgery has been associated with an increased risk of worsening existing macular edema due to post-surgical inflammation that can be further exacerbated by pre-existing diabetic retinopathy.

DEX intravitreal implants are biodegradable implants that deliver a smaller amount of dexamethasone over a 4 to 6-month period. Multiple trials have shown encouraging findings in clinicians utilizing intravitreal DEX implants to manage postoperative macular edema in patients with DME and RVO.²

Kuo and colleagues retrospectively examined the pre-operative use of intravitreal DEX implants in patients with macular edema undergoing cataract surgery study at the National Cheng Kung University Hospital in Taiwan. A total of 19 eyes of 16 patients with diabetic macular edema (DME) or macular edema associated with RVO were enrolled in the study. Only those who received DEX implant injections and cataract surgery within 3 months were included in the analysis.

All study participants received an intravitreal DEX implant at baseline and underwent cataract surgery, phacoemulsification, and posterior chamber intraocular lens implantation) within 3 months after its insertion. The investigative team evaluated best-corrected visual acuity (BCVA), central subfield thickness (CST), and intraocular pressure (IOP) changes between baseline, time of cataract surgery and postoperative months.

Most study participants were women (75%), had a mean age of 72.5 years, and were diagnosed with DME (68.8%) compared to RVO (31.2%). The analysis indicated 8 of 19 eyes (42.1%) had a recurrence of macular edema during follow-up and received a re-injection of the DEX implant. Intervals between re-injection and the baseline were an average of 122.4 days.

At baseline, the mean CST for all eyes was 357.8 µm, which decreased to 280.2 µm one week prior to cataract surgery and remained stable at 279.5 µm one month after cataract surgery. The reduction in mean CST value below baseline remained at postoperative month 6 (319.4 µm).

Kuo and colleagues suggest the “noted lower CST value may indicate that the impact of DEX not only slowed the progression of edema caused by the inflammatory processes that occur during surgery and especially in the post-cataract period, but it also helped cure the edema as well.”

Mean IOP measures were 16.0 mmHg at baseline and the numbers increased to 17.78 mmHg before cataract surgery. At 1 month following surgery, IOP decreased below baseline to 15.1 mmHg, was maintained through months 2 and 3, and ultimately, returned to baseline at months 6 post-surgery (16.2 mmHg).

Investigators noted, on average, no additional IOP-lowering drugs were needed during the follow-up at month 6 post-surgery.

The mean baseline BCVA measure was logMAR 0.943, before improving to logMAR 0.532 at 6 months post-surgery. All study participants experienced improvements in their vision, according to investigators.

Limitations in the number of study eyes led investigators to call for larger studies with enough statistical power to detect differences in outcomes after DEX implants in those receiving cataract surgery.

“More research is essential to distinguish between diabetic people who are more likely to acquire ME and to validate the long-term effects and tolerability of DEX implants followed by a simple cataract surgery,” investigators wrote.

References

1. Lai CC, Kuo SC. Real-world experience on intravitreal dexamethasone implant in patients with macular edema scheduled to undergo cataract surgery. BMC Ophthalmol. 2023;23(1):352. Published 2023 Aug 9. doi:10.1186/s12886-023-03093-y
2. Furino C, Boscia F, Niro A, Giancipoli E, Grassi MO, D’amico Ricci G et al. Combined phacoemulsification and intravitreal dexamethasone implant (Ozurdex®) in diabetic patients with coexisting cataract and diabetic macular edema. J Ophthalmol 2017;2017