Outcomes After Vitrectomy in Eyes With Tractional Diabetic Macular Edema

Anatomical and Functional Outcomes After Vitrectomy in Eyes With Tractional Diabetic Macular Edema

1. assessment the outcomes of vitrectomy on retinal function by mf-ERG (multifocal electroretinogram) and anatomy by OCT (optical coherence tomography) in patients with tractional diabetic macular edema (TDME) .
2. To correlate the postoperative corrected distance visual acuity (CDVA) with the mf-ERG and OCT findings following vitrectomy surgery for TDME.

Diabetic retinopathy (DR) is one of the leading causes of vision loss worldwide [1]. In 2010, DR affected more than 93 million individuals worldwide, 28 million of whom experienced vision-threatening DR[2].

Diabetic macular edema (DME) is a common cause of visual loss in diabetic retinopathy (DR) and is a complication in any stages of DR including proliferative diabetic retinopathy (PDR)[3].

The terms vitreous traction maculopathy, vitreous induced diabetic macular edema and maculopathy due to posterior hyaloid traction are synonymous and describe a pattern of diabetic maculopathy which is characterized by: (1) The absence of complete posterior vitreous detachment; (2) An increased retinal thickness in the center of the macula, and (3) a characteristic reflex of the vitreoretinal interface[4]. there are multiple factors in the vitreomacular interface including ERM, taut posterior cortices, vitreoschisis, PVD, and adhesions [5]. Anomalous PVD generates antero-posterior and tangential traction forces at the vitreo-retinal interface that act upon the inner and outer retinal layers [6]. Until recently, the only treatment option available for VMA was vitrectomy[7].

Few studies have used the multifocal electroretinogram (mfERG) technique to investigate the effects of vitrectomy on macular visual function for DME [8]. Mf-ERG is an objective electrophysiologic technique that measures the electrical changes in the central retinal area. This technique accurately assess the electrophysiologic activity in multiple retinal areas, and gives us a topographic charting of retinal function [9] .

Inclusion Criteria:

• Age ≥18 years; type 1 or 2 diabetes
• TDME as the indication for vitrectomy; central foveal thickness (CFT) ≥300 µm as measured by spectral-domain optical coherence tomography (SD-OCT) , We defined VMIA on OCT as ERM, anomalous vitreomacular adhesions, or both , ), and possible visual acuity impairment attributed to foveal thickening due to DME.

Exclusion Criteria:

• A history of other retinal diseases; or active ocular inflammation or infection or glaucoma .
• Eyes with macular edema from etiologies other than diabetes
• Dense refractive media opacity before and after surgery, such as dense cataract, vitreous hemorrhage which can conceal fundus visualization and OCT measurements
• Central retinal ischemia detected by intravenous fluorescein angiograms.
• A history of vitrectomy
• A visual acuity worse than 1\60 and the duration of tractional ERM is more than 12 months.