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Medical and Mathematical Background
Published in Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza, Computer-Aided Glaucoma Diagnosis System, 2020
Arwa Ahmed Gasm Elseid, Alnazier Osman Mohammed Hamza
The clinical examination of glaucoma has a wide variety of modalities that contribute to the identification of the disease. This variation of modalities arises from the complex nature of the glaucoma pathology, where no single modality can provide a definite decision. For example, measuring the IOP as a major risk factor for glaucoma is not sufficient because its increase could be due to other diseases. The examination relies on evaluating the major features of glaucoma, which are the visual function and the appearance of the optic disc. In addition, ocular hypertension is an important indicator of the likelihood of having glaucoma and a determining factor for its progression path.
Introduction to Glaucoma
Published in Neil T. Choplin, Carlo E. Traverso, Atlas of Glaucoma, 2014
Neil T. Choplin, Carlo E. Traverso
The diagnosis of glaucoma may be difficult to make, particularly on a single examination. Considering the progressive nature of the disease, observation of its progression may be necessary for confirmation. Consider the patient whose photograph of the right optic disc is shown in Figure 1.3a. This patient is an African-American male in his mid-50s with elevated intraocular pressure (mid-20s) in both eyes. His visual field examination was entirely within normal limits, and the other eye was identical, that is, symmetrical. He was started on medical therapy to lower his pressure and followed at regular intervals. Figure 1.3b and c are disc photographs of the same eye taken seven and nine years later, respectively. Each time, the visual field remained normal although there was a very subtle but steady decrease in mean sensitivity. The optic discs remained symmetrical. Taken as a series, these photographs demonstrate concentric enlargement of the cup over time, corresponding to the diffuse loss of sensitivity in the visual field. Each individual time period, viewed independently of the rest, is consistent with “ocular hypertension” and might be treated by periodic follow-up visits as with this patient. Viewed as a series, however, this patient clearly has progressive open-angle glaucoma. Glaucoma, therefore, may be like a movie depicting the destruction of the optic nerve with each examination representing but one frame from the movie.
Eczema and the Eye
Published in Donald Rudikoff, Steven R. Cohen, Noah Scheinfeld, Atopic Dermatitis and Eczematous Disorders, 2014
Kevin Stein, Frederick Perreira
Glaucoma occurs as a complication of elevated intraocular pressure. Normal intraocular pressure depends on a balance between the production and outflow of the aqueous humor in the anterior segment of the eye. The function of aqueous humor is to maintain the shape of the eye and to provide nourishment to the lens and cornea. Aqueous humor is formed by the ciliary body in the posterior chamber. From there, it flows through the pupil to the anterior chamber. It leaves the anterior chamber through a sponge-like system of pores called the trabecular meshwork, located at the junction of the cornea and the root of the iris. The trabecular meshwork causes a resistance to flow and elevation of pressure. From the trabecular meshwork, fluid moves into the canal of Schlemm and then to the venous system. Under physiological conditions, a balance exists between fluid production and fluid outflow such that enough internal pressure is present to maintain the overall round shape of the eye. The normal intraocular pressure is 15 mmHg (Lens et al. 1999, Kaufman and Alm 2003). An elevation of intraocular pressure with no other abnormalities is known as ocular hypertension. Ocular hypertension associated with visual field defects or observable damage to the optic nerve is considered glaucoma.
Retinal Vasculitis and Posterior Pole Preretinal Exudates in Exogenous Bacterial Endophthalmitis: Management and Visual Outcomes
Published in Ocular Immunology and Inflammation, 2022
Kuan-Jen Chen, Yen-Po Chen, Nan-Kai Wang, Ming-Hui Sun, Chi-Chin Sun, Wei-Chi Wu, Chi-Chun Lai
Final BCVA was 20/40 or higher (n = 14), 20/200 to 20/50 (n = 9), 2/200 to 19/200 (n = 6), CF (n = 4), LP (n = 3), and NLP (n = 4). Twenty-three eyes (57.5%) had favorable visual outcomes. Final BCVA (mean LogMAR 1.18 ± 0.97 [approximately 12/200], range: 0–2.9) improved from presenting VA (mean LogMAR 2.44 ± 0.19 [approximately worse than HM and better LP], range: 2.3–2.9) (P < .001). No eye ultimately underwent evisceration or enucleation. Significantly poor visual outcomes were observed in patients with retinal detachment (P = .005) or silicone oil tamponade (P = .004). Final mean BCVAs in non-ocular hypertension and ocular hypertension patients were LogMAR 0.67 ± 0.61 (approximately 20/100) and LogMAR 2.23 ± 0.68 (approximately CF), respectively (P < .001). In 13 patients with ocular hypertension at presentation, no eyes developed ocular hypertension during follow-up. The patients with ocular hypertension exhibited significantly poor visual outcomes than those without ocular hypertension (P < .001).
Sustained latanoprost release from PEGylated solid lipid nanoparticle-laden soft contact lens to treat glaucoma
Published in Pharmaceutical Development and Technology, 2022
Hui Dang, Chunyun Dong, Li Zhang
Latanoprost is an ester analogue that reduces the intra ocular pressure (IOP) by increasing the uveoscleral outflow (Watson et al. 1996). It is widely accepted for the treatment of ocular hypertension using eye drop solution (Rouland et al. 2013). However, eye drop therapy shows poor ocular bioavailability due to loss of drug via nasolacrimal drainage, improper absorption, and other associated corneal barriers (Desai et al. 2019; Lanier et al. 2021; Maulvi et al. 2021). The poor patient compliance and low adherence rate (<50%) contribute to irreversible vision loss (Schwartz and Quigley 2008; Friedman et al. 2009). The patient adherence to glaucoma therapy can be improved by developing therapeutic contact lenses to deliver drugs for the prolong period of time (Gupta and Aqil 2012; Holgado et al. 2020). The contact lens can improve ocular bioavailability up to 50% compared to eye drop solutions (Hiratani et al. 2005; Maulvi et al. 2021). Formulators have developed methods to incorporate ophthalmic drugs into the contact lenses, including molecular imprinting, use of vitamin E as a barrier, polymeric nanoparticles, application of supercritical fluids, implantation techniques, and coating (Guzman-Aranguez et al. 2013; Maulvi et al. 2016). Although these approaches afforded controlled and prolonged drug release profiles with improved ocular drug retention, they are not suitable for clinical application owing to alterations in the critical properties of the lens, such as swelling, oxygen permeability, and optical transparency (Lanier et al. 2020; Zhang et al. 2020).
Thyroid-Associated Orbitopathy: Management and Treatment
Published in Journal of Binocular Vision and Ocular Motility, 2022
Lauren Hennein, Shira L. Robbins
Corticosteroids are often the first-line treatment for active TAO patients. Initial therapy can include a trial of systemic corticosteroids (oral prednisone 1.0 to 1.5 mg/kg/day or intravenous methylprednisolone 1 g for a total of 3 doses).34 While steroids improve inflammation, the side effects of steroids are significant10 and thus shared decision-making with the patient and provider is important when considering steroid initiation. Oral corticosteroids are associated with significant systemic side effects including cushingoid features, diabetes mellitus, infections, osteoporosis, hypertension, hirsutism, and cataract formation.32 Ocular hypertension and glaucoma are also important considerations that require monitoring. The long-term side effects of oral corticosteroids are often more pronounced than IV corticosteroids since oral therapy is typically administered for a longer period of time.32 Radioiodine therapy in TAO patients may worsen ophthalmopathy, and there is some evidence that oral prednisone may prevent worsening of ophthalmopathy after radioiodine therapy.33,68