Dr. Paul Walia Publishes Article Featured on the Retinal Physician’s Diabetes Ophthalmic eUPDATE

The September 2016 Diabetes Ophthalmic eUPDATE newsletter, a monthly email from the Publishers of Retinal Physician, published an article written by Dr. Paul Walia. Georgia Retina is proud to share Dr. this article on the Role of Vitrectomy in the Management of DME.

The Role of Vitrectomy in the Management of DME
No longer a therapy of last resort
By Harpreet (Paul) S. Walia, MD

Diabetic macular edema (DME) is a multifactorial disease driven by biochemical, inflammatory, vascular, and mechanical factors. While intravitreal pharmacotherapy has greatly augmented our armamentarium for treating DME, vitrectomy maintains a valuable role, particularly for reducing mechanical factors.

Vitrectomy Benefits:
The benefits of vitrectomy are three-fold. Removing the vitreous: 1) reduces the depot of chemokine and cytokine mediators involved in the DME cascade; 2) improves posterior segment oxygenation and subsequent macular perfusion, both of which may reduce DME; and 3) eliminates tractional factors when present, such as a taut posterior hyaloid and epiretinal membrane. Surgery enables us to remove the diabetic internal limiting membrane, which may be thickened and comprised of higher levels of collagen, fibronectin, and laminin, creating a barrier to effective pharmacotherapy.

Numerous retrospective series report that vitrectomy reduces central foveal thickness and improves vision.1 The Diabetic Retinopathy Clinical Research Network’s Protocol D study showed that vitrectomy reduced central foveal thickness nearly 200 microns, and 38% of eyes gained 10 or more letters at 6 months, while only 22% lost 10 or more letters.2,3 The absence of a standardized protocol and inclusion criteria of eyes undergoing vitrectomy for DME makes it challenging to apply these results to clinical practice.

Role in Combination Therapy:
Vitrectomy was previously considered a last resort treatment for chronic, refractory cases of DME, but that is not necessarily the case today. With advancements in vitreoretinal surgery, including small-gauge instrumentation and chromovitrectomy, typically we can expect a reduction in central foveal thickness and potentially improved vision with a faster postoperative recovery.

In addition, post-vitrectomy DME can be managed with focal laser and extended-release intravitreal steroid implants, such as dexamethasone 0.7 mg (Ozurdex, Allergan) and fluocinolone acetonide 0.19 mg (Iluvien, Alimera Sciences). There is some evidence to suggest that anti-VEGF agents do not have altered clearance rates in vitrectomized eyes and can still be utilized effectively after vitrectomy.4

Summary:
As the incidence of diabetic eye disease increases and with continued advancements in vitreoretinal surgery, retina specialists are reevaluating the role of vitrectomy in our treatment paradigms.

Reference(s)
1. Hassan TS. Is vitrectomy an appropriate treatment for DME in 2014? Retina Today. 2014;Jan-Feb:52-55.
2. Haller JA, Qin H, Apte RS, et al.; Diabetic Retinopathy Clinical Research Network Writing Committee. Vitrectomy outcomes in eyes with diabetic macular edema and vitreomacular traction. Ophthalmology. 2010;117:1087-1093.
3. Flaxel CJ, Edwards AR, Aiello LP, et al. Factors associated with visual acuity outcomes after vitrectomy for diabetic macular edema: diabetic retinopathy clinical research network. Retina. 2010;30:1488-1495.
4. Bressler SB, Melia M, Glassman AR, et al.; Diabetic Retinopathy Clinical Research Network. Ranibizumab plus prompt or deferred laser for diabetic macular edema in eyes with vitrectomy prior to anti-vascular endothelial growth factor therapy. Retina. 2015;35:2516-2528.