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Vitreoretinal
Published in Mostafa Khalil, Omar Kouli, The Duke Elder Exam of Ophthalmology, 2019
A break in the choroid may result from closed globe injury due to blunt trauma. There is usually disruption of the choroid, Bruch membrane and RPE; however, the neurosensory retina is unaffected. On examination, a crescent-shaped yellow subretinal streak is seen usually adjacent to the optic disc.
B
Published in Anton Sebastian, A Dictionary of the History of Medicine, 2018
Bruch Membrane A transparent membrane adjoining the retina, separating it from the capillaries of the choroid. Described in 1844 by Karl Wilhelm Ludwig Bruch (1819–1884), a German professor of anatomy at Basel and Giessen.
Effect of Nintedanib Nanothermoreversible Hydrogel on Neovascularization in an Ocular Alkali Burn Rat Model
Published in Current Eye Research, 2022
Xiaotian Liu, Shanjun Wu, Yan Gong, Lili Yang
In addition to corneal vascularization, the abnormal increase of neovascularization and the abnormally high expression of angiogenesis factors (VEGFA and CD31) in choroids also aroused our attention. Choroidal neovascularization may pass through the Bruch membrane into abnormal growth of the space beneath the retinal pigment epithelium or the subretinal retina. If the central retina, which is responsible for vision, is involved, choroidal neovascularization can lead to distorted vision, affecting central vision or even loss of vision.30 Choroidal neovascularization is also considered a complication after alkali burn. Effective control of choroidal neovascularization will benefit the treatment and recovery of the eye after an alkali burn.31,32 We believe this may be related to the massive inflammatory response of alkali burn. The intense storm of inflammatory factors after corneal burn will stimulate the formation of new blood vessels in the choroid.33 In this study, the levels of inflammatory cytokines were also measured, and the results showed that both nintedanib nanoparticles and thermosensitive adhesive significantly inhibited the secretion of inflammatory cytokines IL-6, IL-1β, and TNF-α in eyeball tissues. This plays an essential role in the inhibition of choroidal neovascularization. Moreover, nintedanib has been shown to have a wide range of anti-inflammatory effects.34–36 Therefore, we believe that the inhibition of choroidal neovascularization by NintedanIb may be due to the inhibition of inflammatory response in situ in corneal alkali burn.
Automatic Segment and Quantify Choroid Layer in Myopic eyes: Deep Learning based Model
Published in Seminars in Ophthalmology, 2022
Chung-Hao Hsiao, Yu-Len Huang, Siu-Lun Tse, Wei-Ping Hsia, Hung-Ju Chen, Yuan-Shao Cheng, Chia-Jen Chang
Deep learning algorithms were also utilized to segment the choroid layer. Masood et al.32 proposed a two-stage segmentation method to segment out the Bruch membrane and choroid and calculate the thickness map. A series of morphological operations were used to segment Bruch membrane, while the choroid was segmented using CNN. In their study, the unsigned border positioning errors were 1.39 ± 0.25 pixels for Bruch membrane extraction and 2.89 ± 1.05 pixels for choroid segmentation. Zhang et al.33 proposed a Biomarker-infused global-to-local Network (Bio-Net) for choroid segmentation in 20 different normal eyes, where thickness difference was 4.30 ± 0.02 pixels. Zheng et al.34 utilized modified residual U-Net architecture to segment the choroid boundaries. In their article, 95.68% images of the upper choroidal boundary and 90.57% images of the lower choroidal boundary had a difference within 0.08 mm between the location measured automatically and the ground truth.
Neuro-Ophthalmic Literature Review
Published in Neuro-Ophthalmology, 2022
David A. Bellows, Noel C.Y. Chan, John J. Chen, Hui-Chen Cheng, Peter W. MacIntosh, Michael S. Vaphiades, Xiaojun Zhang
Sildenafil citrate, a selective oral phosphodiesterase 5 inhibitor, is a widely used drug for erectile dysfunction that acts by elevating cyclic guanosine monophosphate levels and causing smooth muscle relaxation. It also has 10% activity against phosphodiesterase 6, a key enzyme in the phototransduction cascade in the retina. Recent ocular imaging developments have further revealed the influence of sildenafil on ocular haemodynamics, particularly choroidal perfusion. Choroidal thickness is increased, and choroidal perfusion is also enhanced by autoregulatory mechanisms that are further dependent on age and microvascular abnormalities. Studies demonstrating high intraocular pressure via a “parallel pathway” from increased choroidal volume and blood flow to the ciliary body have challenged previous concepts. Another new observation is the effect of sildenafil on bipolar cells and cyclic-nucleotide gated channels. The authors discuss potential deleterious effects (central serous chorioretinopathy, glaucoma, ischaemic optic neuropathy, and risks to recessive carriers of retinitis pigmentosa), potential beneficial effects (amelioration of choroidal ischaemia, prevention of thickening of Bruch membrane, and promotion of recovery of the ellipsoid zone) in macular degeneration, as well as potential drug interactions of sildenafil.