Symmetry of peripheral retinal nonperfusion in diabetic retinopathy by ischemic index

Increasing prevalence of diabetes mellitus warrants recognition of factors related to asymmetric diabetic retinopathy (DR). This thematic synthesis based on an iterative literature review conducted in Medline and Google Scholar pertaining to diabetes with coexistent asymmetry of retinopathy included 45 original articles, 21 case reports and series, and 18 review articles from 1965 to 2020. Asymmetric DR is defined as proliferative DR (PDR) in one eye and nonproliferative, preproliferative, background, or no DR in the other eye lasting for at least 2 years. It is observed in 5%–10% of patients with PDR. Associated factors can be divided into (i) vascular: carotid obstructive disease, ocular ischemic syndrome, and retinal vascular diseases; (ii) Inflammatory: uveitis, endophthalmitis, and Fuchs’ heterochromic cyclitis; (iii) degenerative: posterior vitreous detachment, high myopia and anisometropia, uveal coloboma, retinal detachment, retinitis pigmentosa, and chorioretinal atrophy and scarring; (iv) cataract surgery and vitrectomy; and (v) miscellaneous: elevated intraocular pressure, glaucoma, amblyopia, retinal detachment, and optic atrophy. The gamut of diagnostic modalities for asymmetric DR includes thorough ocular examination, slit-lamp biomicroscopy, fundus photography, fundus fluorescein angiography, optical coherence tomography, and newer modalities such as ultra-widefield fluorescein angiography and optical coherence tomography angiography, along with a complete systemic evaluation and carotid Doppler studies. The differential diagnosis includes other causes of retinal neovascularization that may present in an asymmetric manner, such as sickle cell retinopathy, retinal vein occlusions, and featureless retina. This review discusses in detail the aforementioned considerations and draws a comprehensive picture of asymmetric DR in order to sensitize ophthalmologists to this important condition.

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“…Some of these limitations can be minimized by comparing UWF-FA to color UWF photographs obtained in the same sitting. [ 84 85 86 ]…”

Section: Diagnostic Toolsmentioning

confidence: 99%

“…Symmetry is defined as the “likeness of the total value of peripheral nonperfusion as measured by ischemic index in the right eye compared to the left eye.” However, no cutoff value of symmetry based on the ISI difference between the two eyes has been defined. [ 86 ]…”

Section: Diagnostic Toolsmentioning

confidence: 99%

Asymmetric diabetic retinopathy

Azad

Sinha

Nishant

2021

Indian Journal of Ophthalmology

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“…UWFA has been used to evaluate the peripheral retina for central retinal vein occlusion [7][8][9][10], branch and hemicentral retinal vein occlusion [11][12][13][14], diabetic retinopathy [15][16][17][18][19][20][21], and recalcitrant diabetic macular edema [22]. However, there is no prior study using UWFA to characterize newly diagnosed NVG.…”

Section: Introductionmentioning

confidence: 99%

Ischemic index and distribution of retinal capillary non-perfusion in neovascular glaucoma

DeBoer¹,

Wong²,

Ameri³

2022

Front. Biosci. (Landmark Ed)

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Introduction: Neovascular Glaucoma (NVG) is a condition normally caused by hypoxic posterior ocular disease, which produces angiogenic factors such as vascular endothelial growth factor (VEGF) that stimulate new vessel proliferation of the anterior segment and angle, eventually leading to angle closure, reduced outflow of aqueous humor and increased intraocular pressure. Without treatment elevated intraocular pressure can rapidly progress to loss of vision. Treatment includes addressing the intraocular pressure and reducing the ischemic drive with panretinal photocoagulation (PRP) of the ischemic retina. Recent imaging advancements allow for ultra-widefield fluorescein angiography (UWFA) which expand the amount of peripheral retina that can be evaluated for non-perfusion. Here we aim to study patterns of non-perfusion in NVG using a group of PRP naïve patients with recent onset NVG. Methods: This study is a retrospective single-center cross-sectional study of patients seen at LAC + USC Medical Center from January 2015 to April 2020 with new onset NVG, without PRP and with UWFA completed. The percentage of ischemic index of the retina was calculated from the UWFA and evaluated in three distinct zones centered on the fovea: the posterior pole, the mid periphery, and far periphery. To increase sample size, a confirmatory group was included, with PRP allowed prior to UWFA but not before diagnosis. In addition, the time between diagnosis and UWFA was increased to 6 months. Results: A total of 11 eyes met inclusion criteria for the primary group. Ischemic index was found to be 91% in the far periphery, 77% in the mid periphery, and 42% at the posterior pole. The total average ischemic index was 76%. There was a statistically significant difference between the far periphery and posterior pole and mid periphery and posterior pole. A total of 24 eyes met criteria for the confirmatory group. Ischemic index for the confirmatory group was found to be 93% in the far periphery, 75% in the mid periphery, and 35% at the posterior pole. There was a statistically significant difference between the far periphery, posterior pole and mid-periphery. Conclusion: This knowledge can be used to further guide treatment and understand risk for NVG.

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“…UWFA has been used to evaluate the peripheral retina for central retinal vein occlusion [7][8][9][10], branch and hemicentral retinal vein occlusion [11][12][13][14], diabetic retinopathy [15][16][17][18][19][20], and recalcitrant diabetic macular edema [21]. However, there is no prior study using UWFA to characterize newly diagnosed NVG.…”

Section: Introductionmentioning

confidence: 99%

“…al used levels of ischemia to set a threshold of 118.3 disc diameters of ischemia for identi cation of proliferative diabetic retinopathy[19]. Speilburg found increasing levels of ischemia with worsening retinopathy, with mild non-proliferative diabetic retinopathy (NPDR) having an ISI of 2.2% and PDR having an ISI of 18.6%[20]. This trend held true in patients with recalcitrant macular edema.…”

mentioning

confidence: 99%

Ischemic Index and Distribution of Retinal Capillary Non-perfusion in Neovascular Glaucoma: a Retrospective Study

DeBoer¹,

Wong²,

Ameri³

2021

Preprint

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Purpose: To evaluate the pattern of retinal ischemia in newly diagnosed neovascular glaucoma (NVG).Methods: This is a retrospective single-center cross-sectional study of patients seen at LAC+USC Medical Center from January 2015 to April 2020. Patients with newly diagnosed NVG and ultra-widefield fluorescein angiography (UWFA) without prior panretinal photocoagulation were included. A total of 11 eyes from 10 patients met inclusion criteria. Three zones centered on the fovea were defined: posterior pole (within 2 disc-fovea lengths), mid periphery (between 2 and 3 disc-fovea lengths), and far periphery (>3 disc-fovea lengths). Ischemic index was calculated in these zones using ImageJ software.Results: The etiology of NVG was from proliferative diabetic retinopathy (n=9) and central retinal vein occlusion (n=2). Patients were aged between 48-74 years old. Ischemic index was found to be 91% in the far periphery, 77% in the mid periphery, and 42% at the posterior pole. The total average ischemic index was 76%. There was a statistically significant difference between the far periphery and posterior pole and mid periphery and posterior pole.Conclusions: High levels of retinal ischemia were found with newly diagnosed NVG. The pattern of ischemia was more pronounced in the far periphery than posterior pole.

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Symmetry of peripheral retinal nonperfusion in diabetic retinopathy by ischemic index

Cited by 8 publications

References 16 publications

Asymmetric diabetic retinopathy

Asymmetric diabetic retinopathy

Ischemic index and distribution of retinal capillary non-perfusion in neovascular glaucoma

Ischemic Index and Distribution of Retinal Capillary Non-perfusion in Neovascular Glaucoma: a Retrospective Study

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