diabetic%20retinopathy
DIABETIC RETINOPATHY
Diabetic retinopathy is an abnormality of the microvasculature of the retina that occurs to almost all patients with chronic diabetes mellitus.
It is one of the leading cause of blindness worldwide and principal cause of impaired vision in patients aged 25-75 years of age.
The abnormality causes microaneurysms, retinal hemorrhages, lipid exudates, macular edema & neovascular vessel growth that may lead to blindness.

Pharmacotherapy

Intravitreal Triamcinolone Acetonide (IVTA)

  • Studies showed that IVTA inhibits VEGF-induced breakdown of the blood retinal barrier
  • Also, studies have shown that although IVTA resulted in some reduction of macular edema, the long-term (2 yr) effect was not as good as focal laser photocoagulation
  • Used in visualization during vitrectomy
  • Under investigation for use in DME that persists after focal/grid laser treatment, in cases of extensive macular hard exudate deposition & adjunct to panretinal photocoagulation treatment of PDR
  • Complications may include increased intraocular pressure & cataract

Intravitreal Anti-Vascular Endothelial Growth Factor (Anti-VEGF)

  • Studies show that it inhibits the increase in retinal vascular permeability mediated in part by protein kinase C
  • Under investigation for use in managing PDR, CSME & more advanced retinal disease eg proliferative vascular changes & neovascularization in the cases of retinal ischemia
  • Bevacizumab & Ranibizumab are recombinant humanized antibodies
    • Studies have shown that these drugs reduce OCT macular thickness, PDR activity & severity, & improve visual acuity (1-2 lines on a Snellen chart)
    • Ranibizumab is currently being used in the treatment of DME
  • Pegaptanib is an RNA aptamer that specifically binds & inhibits VEGF-165, which is responsible for neovascularization & vascular permeability, & has been shown in studies to reduce OCT macular thickness & visual loss to DME

Intravitreal Ovine Hyaluronidase

  • Clinical trials have shown to be safe & modestly effective in the clearing of vitreous hemorrhage in PDR

Intravitreal Plasmin

  • Studies have shown that it cleaves the vitreoretinal junction & allows less traumatic removal of the posterior hyaloid

Intravitreal Glucocorticoids

  • Eg Fluocinolone
  • Studies have shown that they reduce neovascularization & retinal inflammation & may restore the integrity of the blood-retina barrier by increasing tight-junction protein expression
  • May cause high risk rates of increased IOP, cataract formation & endophthalmitis

Intravitreal Dexamethasone

  • Studies have shown that intravitreal Dexamethasone implant improves vision & vascular leakage from DME in victrectomized patients

Ruboxistaurin

  • Has been shown by studies to be associated w/ a reduction in retinal vascular leakage, as measured by vitreous fluorometry, but visual acuity was not affected
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