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An Approach to Visual Loss in a Child
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Muhammad Hassaan Ali, Stacy L. Pineles
Impaired vision in early childhood can be due to multiple causes that include congenital malformations, acquired ophthalmic disorders, or lesions of the anterior or posterior visual pathway. A careful examination of the patient can help the clinician identify some of the evident anterior segment disorders like congenital cataract, corneal opacities and refractive errors. However, some retinal pathologies like congenital stationary night blindness (CSNB), Leber's congenital amaurosis (LCA) and achromatopsia do not show any characteristic lesions on the retina in early stages and have to be diagnosed on the basis of electroretinography (ERG) (1–3). An important finding in all such cases is arteriolar narrowing and waxy disc pallor which should alert the clinician to order ERG in such cases (4). It is generally advised to wait till 1 year of life to derive conclusive findings from ERG owing to slow maturation of rod and cone maturation in the first year of life. Similarly, cerebral visual impairment may also be suspected clinically but demands detailed high-resolution neuroimaging for confirmation.
Pathological Processes of the Eye Related to Chemical Exposure
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
In properly examining the eyes of any animal species clinically, the observer must separately evaluate the ocular fundus and the anterior segment and adnexa. The ocular fundus refers to that portion of the eye extending posteriorly from the anterior edge of the retina; including the retinal vasculature, the choroid, the optic nerve, and in some instances, the sclera.1 The anterior segment includes the iris, the lens, the anterior chamber, and the cornea. The adnexa refers to the eyelids and lacrimal apparatus and the conjunctivae (palpebral and bulbar).2 Examination of these structures requires the use of appropriate instrumentation and, when indicated, mydriatics or staining agents.
Prenatal Cocaine Exposure and the Eye
Published in Richard J. Konkol, George D. Olsen, Prenatal Cocaine Exposure, 2020
William V. Good, Beatrice Latal Hajnal, Donna M. Ferriero
Briefly, substance-abusing mothers often cannot provide an honest or clear history concerning patterns of abuse. Assays for cocaine exposure can be performed on mothers and babies, but assays for other substances of abuse might be negative if performed more than days after the last episode of substance abuse. This is most obvious in the case of alcohol abuse. It is difficult to obtain accurate data regarding exposure to alcohol, and there is no good measurement of cumulative gestational exposure. Alcohol has been implicated in many of the visual defects seen with cocaine exposure, such as retinal vessel tortuosity and optic nerve hypoplasia.5,6 Strabismus, microophthalmia, and anterior segment dysgenesis have also been documented.
Smartphone-based Anterior Segment Imaging: A Comparative Diagnostic Accuracy Study of a Potential Tool for Blindness Prevalence Surveys
Published in Ophthalmic Epidemiology, 2022
Ashish Kumar, Ferhina S. Ali, Valerie M. Stevens, Jason S. Melo, N. Venkatesh Prajna, Prajna Lalitha, Muthiah Srinivasan, Gopal Bhandari, Sadhan Bhandari, Robi N. Maamari, Daniel A. Fletcher, Thomas M. Lietman, Jeremy D. Keenan
This study has limitations. The study was designed around corneal opacities, and thus the results cannot be extrapolated to other anterior segment pathology (e.g., cataract, pterygium). Moreover, none of the camera modalities image the posterior segment. A single SLR and smartphone camera were studied, and it is unclear whether other smartphones will perform as well, although it is reasonable to expect that more recent smartphones would generally have even better cameras than the smartphone used in this study. The eligibility for the study was based on a corneal scraping, so the results are likely only generalizable to patients with a corneal ulcer severe enough to present for care and undergo corneal cultures. The study’s generalizability outside the Indian subcontinent is also unclear given the severity of corneal ulcers in this part of the world. Moreover, although a random sample of patients was recalled for the study, not all potential participants were willing or able to return for the study, and it is possible that participants had systematically different levels of scarring than nonparticipants. However, even if the distribution of severity of ulcers was different than other settings, this should not affect the fundamental conclusions of the study given the stratified analyses.
The Role of Inflammatory Cytokines in Neovascularization of Chemical Ocular Injury
Published in Ocular Immunology and Inflammation, 2022
Alireza Shahriary, Milad Sabzevari, Khosrow Jadidi, Farshad Yazdani, Hossein Aghamollaei
Chemical injuries are known as a crucial form of damages with long-term complications to the vision. A great number of these injuries occur when the eye tissues are exposed to the chemical solid, liquid, or aerosol substances.1 Statistics have indicated that chemical injuries mostly happen among people with 20 to 40 years old that occupy in chemical industries, laboratories, and agricultural lands.2 Anterior segment of the eye including ocular surface epithelium, the cornea, and limbus are practically injured by chemical substances. The multilayered structure of the cornea covers the external segment of the eye. Both the cornea and lens in the anterior segment of the eye are avascular to allow light to pass.3 A thin layer of tears supplies oxygen to the non-keratinized epithelium of cornea through diffusion.4 After chemical exposure to the cornea, the surface epithelium is potent to rapid regeneration and renewing; however, severe chemical damage may lead to the initiate immunological reaction.5
Comparison of Intraocular Antibody Measurement, Quantitative Pathogen PCR, and Metagenomic Deep Sequencing of Aqueous Humor in Secondary Glaucoma Associated with Anterior Segment Uveitis
Published in Ocular Immunology and Inflammation, 2022
Li Wang, Zhujian Wang, Jinmin Ma, Qiongfang Li, Xueli Chen, Yuhong Chen, Xinghuai Sun
Anterior segment uveitis usually presents with acute unilateral eye pain, redness, blurring of vision, photophobia and tearing, or chronic asymptomatic or mild blurring of vision. Viral etiology is often suspected when anterior segment uveitis is accompanied by IOP elevation or iris dyspigmentation. The group of disease entity is so-called hypertensive anterior uveitis,27 virus-induced anterior uveitis,28 uveitic glaucoma,29 or uveitis-associated glaucoma.30 Clinical phenotypes cover Posner-Schlossman syndrome (PSS),2 Fuchs heterochromic iridocyclitis (FHI)5 and other anterior segment uveitis with granulomatous keratic precipitates (KPs) and keratitis.31 The most common viruses associated with anterior segment uveitis include human cytomegalovirus (HCMV), herpes simplex virus (HSV), varicella-zoster virus (VZV), and rubella virus (RV).27,31