Intravitreal triamcinolone as adjunctive treatment to laser panretinal photocoagulation for concomitant proliferative diabetic retinopathy and clinically significant macular oedema

Margolis, Ron; Singh, Rishi P.; Bhatnagar, Pawan

doi:10.1111/j.1600-0420.2007.00940.x

Cited by 23 publications

(11 citation statements)

References 23 publications

(26 reference statements)

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“…These treatment modalities will decrease the leakage of proteins into the interstitial tissue compartment and help to restore the osmotic gradient between blood and tissue compartments. This will resolve edema formation according to Starling's law (134)(135)(136) (Fig. 8).…”

Section: How Do We Treat Edema?mentioning

confidence: 98%

Physiology of vitreous surgery

Stefánsson

2008

Graefes Arch Clin Exp Ophthalmol

250

195

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Vitreous surgery has various physiological and clinical consequences, both beneficial and harmful. Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Silicone oil is the exception that proves the rule: it is more viscous than vitreous humour, re-establishes the transport barrier to oxygen and VEGF, and reduces the risk for iris neovascularization in the vitrectomized-lentectomized eye. Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Retinal photocoagulation has repeatedly been shown to improve retinal oxygenation, as does vitrectomy. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids. Starling's law explains vasogenic edema, which is controlled by osmotic and hydrostatic gradients between vessel and tissue. It explains the effect of VEGF-induced vascular permeability changes on plasma protein leakage and the osmotic gradient between vessel and tissue. At the same time, it takes into account hemodynamic changes that affect the hydrostatic gradient. This includes the influence of arterial blood pressure, and the effect oxygen (laser treatment) has in constricting retinal arterioles, increasing their resistance, and thus reducing the hydrostatic pressure in the microcirculation. Reduced capillary hydrostatic pressure and increased osmotic gradient reduce water fluxes from vessel to tissue and reduce edema. Finally, Newton's third law explains that vitreoretinal traction decreases hydrostatic tissue pressure in the retina, increases the pressure gradient between vessel and tissue, and stimulates water fluxes from vessel into tissue, leading to edema.

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Section: How Do We Treat Edema?mentioning

confidence: 98%

Physiology of vitreous surgery

Stefánsson

2008

Graefes Arch Clin Exp Ophthalmol

250

195

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“…Among pharmacological treatments currently under investigation for DME, intravitreal injection (IVT) of triamcinolone acetonide (TA) [13][14][15][16][17][18][19] and of antiangiogenic agents such as bevacizumab, 20 -26 pegaptanib, 27 and ranibizumab 28 has been reported to be associated with favorable remodeling of the macular architecture and visual acuity improvement in primary DME. 6 -17 However, in cases of refractory DME, antivascular endothelial growth factor agents have been reported to have a very transient and subtle effect on best-corrected visual acuity (BCVA) improvement and central macular thickness (CMT) reduction, especially compared with intravitreal triamcinolone.…”

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confidence: 99%

Intravitreal Injection Versus Subtenon Infusion of Triamcinolone Acetonide During Cataract Surgery in Patients With Refractory Diabetic Macular Edema

Takata¹,

Messias²,

Folgosa³

et al. 2010

Retina

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“…17 In line with the previous study, Kaise et al reported that the addition of IVTA to PRP in the treatment of eyes with high-risk PDR and CSME may prevent PRP-induced foveal thickening and loss of vision. 18 To our knowledge, there is no study assessing the beneficial effect of IVTA as an adjunct treatment to PRP and MPC in high-risk PDR with CSME eyes. There is only one report about combined treatment in nonhighrisk PDR and CSME eyes, implying the beneficial role of IVTA as an adjunctive therapy to standard treatment.…”

Section: Discussionmentioning

confidence: 97%

Intravitreal Triamcinolone as an Adjunct to Standard Laser Therapy in Coexisting High-Risk Proliferative Diabetic Retinopathy and Clinically Significant Macular Edema

Mirshahi

Shenazandi²,

Lashay³

et al. 2010

Retina

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Intravitreal triamcinolone as adjunctive treatment to laser panretinal photocoagulation for concomitant proliferative diabetic retinopathy and clinically significant macular oedema

Abstract: The addition of IVTA to PRP in the treatment of eyes with high-risk PDR and CSMO may prevent PRP-induced foveal thickening and loss of vision.

Cited by 23 publications

References 23 publications

Physiology of vitreous surgery

Physiology of vitreous surgery

Intravitreal Injection Versus Subtenon Infusion of Triamcinolone Acetonide During Cataract Surgery in Patients With Refractory Diabetic Macular Edema

Intravitreal Triamcinolone as an Adjunct to Standard Laser Therapy in Coexisting High-Risk Proliferative Diabetic Retinopathy and Clinically Significant Macular Edema

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