Efficacy of Preoperative versus Intraoperative Dexamethasone Implantation in Pars Plana Vitrectomy Combined with Phacoemulsification for Idiopathic Epiretinal Membrane
This prospective randomized study of 53 eyes with idiopathic epiretinal membrane found that while preoperative dexamethasone implantation (7–14 days prior) more rapidly reduced early postoperative macular edema and shortened ERM peeling time compared to intraoperative or no treatment, it offered no significant long-term advantage in visual acuity or central macular thickness at three months over intraoperative administration.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The retina is the light-sensitive layer at the back of the eye that acts like the film in a camera, capturing images and sending them to the brain. Sometimes, a thin, transparent scar tissue called an epiretinal membrane forms on the surface of this delicate tissue. As this membrane grows, it can wrinkle and pull on the retina, distorting vision much like a crumpled piece of plastic wrap over a photograph. To fix this, surgeons perform a delicate procedure to peel away the membrane and clear the vitreous gel inside the eye. However, the act of peeling this tissue often triggers inflammation, causing the center of the retina to swell with fluid. This swelling, known as macular edema, can blur vision and delay recovery, even after the membrane is successfully removed. While doctors have long used steroid implants to calm this inflammation, the timing of when to place these implants has remained a question.
A team of researchers at the Second Affiliated Hospital of Harbin Medical University set out to find the best moment to introduce a dexamethasone implant, a small device that slowly releases a powerful anti-inflammatory steroid. They compared two specific approaches in patients who needed surgery for this membrane and also required cataract removal. One group received the implant a week to two weeks before the surgery began, while another group received it only at the very end of the operation. A third group received no implant at all, serving as a baseline for comparison. The study focused on 53 patients with advanced cases of the condition, tracking how quickly their vision improved, how much their retinal swelling decreased, and how the surgery itself unfolded.
The results revealed that giving the implant before the surgery offered distinct advantages during the operation and in the weeks immediately following it. Patients who received the implant preoperatively experienced significantly less bleeding on the surface of the retina while the surgeon was peeling away the membrane. The surgery itself was faster for this group, with the time required to remove the membrane being noticeably shorter than in the other groups. This suggests that the early dose of steroid may have softened the tissue or reduced the inflammation that makes the membrane stick so tightly, making the delicate work of removal easier and less traumatic.
In the weeks after the operation, the preoperative group also saw their retinal swelling decrease more rapidly than the other groups. By the second month after surgery, the center of the retina in these patients was significantly thinner and less swollen compared to those who received the implant during surgery or those who received none. This faster reduction in swelling indicates that the eye recovered its normal structure sooner. However, by the three-month mark, the final vision scores for all three groups had converged. Regardless of when the implant was given, every patient ended up with a similar level of visual improvement, suggesting that while the timing of the treatment changes the speed of recovery and the ease of the surgery, it does not alter the ultimate visual outcome.
The study also monitored eye pressure, a common concern when using steroid implants. While some patients in all groups experienced a temporary rise in pressure, it remained manageable and did not lead to long-term complications. The researchers noted that for patients with severe, tightly adherent membranes, the preoperative approach offers a way to smooth the path for the surgeon and accelerate early healing. For others with looser membranes, the standard approach of placing the implant at the end of the surgery remains a valid and simpler option. Ultimately, the findings provide a new tool for surgeons to consider, showing that a little preparation before the scalpel touches the eye can make the journey to recovery smoother and quicker.
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