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Radiological Interpretation in Neuro-Ophthalmology
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Chirag Kamal Ahuja, Paramjeet Singh
This chapter will dwell on the premise that neuro-ophthalmology covers essentially all aspects of the neural components of the orbit (essentially the eyeball), the entire visual axis up till the various participating CN nuclei as well as all the supranuclear higher brain structures involved. Additionally, brain disorders having secondary manifestations in the ocular examination will also be discussed. Before embarking on this further, a brief anatomical description of the visual pathway and the nerves contributing to mobility of the eyeball is being highlighted.
Charles Bonnet Syndrome
Published in Alexander R. Toftness, Incredible Consequences of Brain Injury, 2023
This syndrome usually appears as a person ages, and their vision deteriorates. It is most commonly associated with macular degeneration or cataracts, both of which are normal in aging eyes. Macular degeneration is damage to the cells at the back of the eyeball that leads to lower sensitivity to the light coming into the eye, while cataracts are cloudy lenses in the eye, which lead to less light entering the eyeball in the first place. The consequence is the same either way: a decrease in visual input from the eyes to the brain as the aging person loses their eyesight. Other causes of partial blindness can also lead to this syndrome (see Hemianopsia).
3rd Cranial Nerve Palsy
Published in K. Gupta, P. Carmichael, A. Zumla, 100 Short Cases for the MRCP, 2020
K. Gupta, P. Carmichael, A. Zumla
The 3rd cranial nerve (oculomotor nerve) supplies the medial rectus, superior rectus and the inferior oblique muscles. In addition it supplies the pupilloconstrictor and levator palpebrae muscles. It is important to understand the exact role of the extraocular muscles in the movements of the eyeball. For example, if a patient with right-sided 3rd nerve palsy is asked to look straight, the right eye will turn laterally because of the unopposed action of the lateral rectus (supplied by the 6th nerve) and diplopia results. When the patient is asked to look to the far right, both eyes can move in the right direction. If the patient is asked to look to the far left, the right eye (with the 3rd nerve palsy) fails to cross the midline because of the failed action of the medial rectus and diplopia results.
Hyaluronic acid-based nanoparticles to deliver drugs to the ocular posterior segment
Published in Drug Delivery, 2023
The eyeball has a distinct anatomical structure and physiological properties as a specific organ of the human body (Figure 2A). For intravitreal injection, there are several main obstacles in the vitreous and retina that need to be overcome before reaching the target cells. Pharmacological formulation effectiveness is dependent on a detailed understanding of ocular barriers and pharmacokinetics. After intravitreal administration, the drug distribution into the vitreous is affected by drug diffusion, convection, and protein binding. Previous research has examined the effects of particle physicochemical properties, vitreous liquefaction, and vitreous proteins. Intravitreal pharmacokinetics include drug distribution in the posterior segment and elimination via the ocular–blood barrier.
Retinal arcades in posterior microphthalmos: biometric correlation
Published in Clinical and Experimental Optometry, 2023
Ramesh Venkatesh, Pranjal Mishra, Harshita Nahata, Nikitha Gurram Reddy, Naresh Kumar Yadav, Jay Chhablani
One of the most characteristic findings noted with PM is presence of RPMF. RPMF is identified on clinical examination as blunting of foveal reflex with elevated and thickened macular fold with adjacent retinal striae.3,8,9 The formation of RPMF in PM can be explained based on the theory proposed by Boynton and Purnell.10 The inhibition in the eyeball growth causes the macular retinal fold formation and crowding of retinal structures, short axial length and high hyperopia.10 Based on a similar hypothesis, one would expect the retinal arcades at the posterior pole in PM eyes to be closer and narrower compared to normal age- and sex-matched controls. However, there appears to be no information in the literature which discussed this clinical aspect in PM eyes.
Circ_0080940 Regulates miR-139-5p/CTGF Pathway to Promote the Proliferation, Migration, Extracellular Matrix Deposition of Human Tenon’s Capsule Fibroblasts
Published in Current Eye Research, 2023
Yanxi Wang, Yinggui Yu, Manhua Xu, Juan Zhou, Gangjin Kang, Kaiming Li
According to the results of microarray analysis by Shen et al.,19 we selected 4 highly expressed circRNAs to detect their expression in the eyeball fascia tissues of glaucoma patients. The results showed that the expression of circ_0080940 was increased most significantly in glaucoma patients, so we chose circ_0080940 for this study (Figure 2(A)). In the eyeball fascia tissues (n = 9), circ_0080940 was confirmed to be highly expressed in glaucoma patients (Figure 2(B)). Under the treatment with different concentrations of TGF-β1, circ_0080940 expression was markedly increased in HTFs with a dose-dependent manner (Figure 2(C)). The results of RNase R assay and oligo (dT)18 primers indicated that circ_0080940 could resist the digestion of RNase R and could not be amplified with oligo (dT)18 primers (Figure 2(D,E)), indicating that circ_0080940 had the circular structure and no poly-A tail.