Ocular hypertension occurs when intraocular pressure (IOP) is greater than the normal range with no evidence of vision loss or damage to the optic nerve. Individuals with ocular hypertension have an increased risk for glaucoma. The mean normal IOP is 15 mmHg and the mean IOP of untreated glaucoma is 18 mmHg. Elevated IOP commonly occurs in patients over the age of 50 and is often due to enlargement of the lens, narrowing of the angle, iridolenticular apposition, and pigment liberation that obstructs the trabecular meshwork. Cataract surgery and lensectomy can lower IOP and reduce the risk of glaucoma. The global wealth inequality of Blacks has created health inequities that have led to decreased access to surgical care contributing to higher rates of blindness from glaucoma. Greater education on the benefits of early cataract surgery and trabecular bypass for higher risk patients, as well as addressing wealth and health inequities, can help to bend the curve of blindness from glaucoma.
Part of the book: Ocular Hypertension
Glaucoma is a common cause of blindness worldwide, affecting patients at an average age of 57 years old. This is a disease of ocular anatomy commonly caused by a blockage of trabecular meshwork leading to an increase in intraocular pressure and glaucomatous optic neuropathy. The lens enlarges in width with age, often contributing to this, with obstruction of the angle due to pupillary block in angle-closure glaucoma. In open-angle glaucoma, there is often increased pigment liberation and obstruction of the trabecular meshwork due to increased iridolenticular and zonular contact. Recent studies looking at cataract extraction, refractive lensectomy, and the Hydrus stent have demonstrated adequate safety and efficacy for the treatment of glaucoma. We review the latest glaucoma treatment algorithm and results with early cataract surgery/refractive lensectomy and microinvasive glaucoma surgery to be considered as initial treatment for patients with glaucoma over 50 years of age.
Part of the book: Refractive Surgery
Ocular hypertension (OHT) is characterized by elevated intraocular pressure (IOP), without any visible optic nerve damage or visual field loss. The mean normal intraocular pressure is 15 mm Hg, and the mean intraocular pressure in patients with untreated glaucoma is 18 mm Hg. However, simply having ocular hypertension does not necessarily lead to the development of glaucoma, instead, it is deemed a considerable risk factor. An example is a person with thick corneas who may have no glaucomatous damage with an IOP of 24 mm Hg. Thus, early detection and management of OHT and corneal pachymetry are imperative to help detect higher risk patients with thinner corneas with ocular hypertension or glaucoma early. The Laroche Glaucoma calculator is an effective inexpensive method to detect patients with glaucoma, glaucoma suspects, and ocular hypertensive with a higher risk of thinner corneas and older age. With respect to the physiology of ocular hypertension, the anterior chamber angle anatomy serves a crucial role in the regulation of IOP. Gonioscopy is an important technique for examining the angle structures, which provides essential information regarding the status of the trabecular meshwork and how this can affect aqueous outflow. This chapter will further explore the anatomy and physiology of the anterior chamber angle, specific principles, techniques, and interpretation of gonioscopy, the significance of early detection as well as the management of OHT.
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