• 10Jan

    Advanced glaucoma – what is it?

    The intra-ocular fluid or aqueous humour is produced by ciliary body of the eye, located in posterior chamber. Aqueous flows from the posterior chamber via the pupil into the anterior chamber, from where it exits the eye by two different routes. It drains into a canal at the margin of the cornea and is called canal of Schlemm. About 10% also drains via venous outflow of ciliary body, choroid and sclera. 


    Intra-ocular pressure

    The intra-ocular pressure depends on the rate of production and outflow of aqueous humour. The normal pressure is 11 to 21 mmHg.

    Glaucoma

    In this condition, raised intra-ocular pressure results in progressive optic nerve damage and visual field loss. It affects 2% of population above 40 years of age and 10% above the age of 80. In many cases this condition remains undiagnosed. Glaucoma is one of the commonest causes of blindness all over the world.

    Advanced glaucoma

    This is seen in late stage of glaucoma. About 10 to 40% of patients present with advanced disease. The loss of visual field and acuity are both affected. This reduces the performance of the patient. Advanced glaucoma can be defined on the basis of patient’s ability to perform activities of daily living. Functional tests are usually more useful than physical parameters for follow-up of patients with advanced glaucoma.

    Advanced glaucomaFundoscopy shows optic atrophy with cupping of the optic nerve head. If the progressive changes of glaucoma induced optic atrophy are not prevented by appropriate treatment to reduce the IOP, it eventually results in loss of all neural rim tissue. The final result is total cupping, which is seen on fundoscopy as a white disc with loss of all neural rim tissue and bending of all vessels at the margin of the disc. This is called bean pot cupping due to its appearance on cross section.

    Visual field defects in advanced glaucoma

    There is extensive loss of visual field which may progress to blindness. The natural progression of glaucomatous field loss involves the development of arcuate shaped blind spots, which fuse nasally at the horizontal axis and may extend to the peripheral limits in all areas except temporal fields. This results in central and temporal islands of vision in advanced glaucoma. With continued damage, these islands of vision diminish in size until the central island disappears completely. The temporal island of vision is more resistant and may persist long after central vision is lost. However, this may also ultimately disappear if the glaucoma is not controlled. This leaves the patient totally blind.

    Treatment options 

    The most effective method of treatment is to reduce intra-ocular pressure. The extent of lowering of IOP is related to changes in visual fields. Clinical studies have shown that that progression was least when IOP was maintained below 18 mm Hg. Clinical evidence also suggests that more advanced glaucoma is more likely to progress than earlier stages of the disease and may require greater IOP lowering to halt progression.

    The treatment options include medical therapy, laser therapy and surgery. The treatment is started with topical or intra-ocular eye-drops. The dose is titrated as per the IOP and symptomatic improvement. In a situation where the IOP control is not adequate, laser therapy or surgery is done. Argon or selective laser trabeculoplasty is usually done. Surgery lowers IOP more than medication as concluded by multiple clinical trials. Advanced Glaucoma Intervention Study data suggest that consistent, low IOPs with minimal IOP variation is associated with reduced progression of visual field in patients with advanced glaucoma.

    Glaucoma presents with reduction in visual field which progresses to blindness. Opinion of an ophthalmologist should be taken timely so as to delay the progression of visual loss and maintain an independent level of daily living.

    Anna L.

    It’s all about health!
    I have academic background in drugs related Chemical Technology, as well as extensive professional experience in pharma and medical companies. My main area of interest is everyday life medicine. The goal of my articles is to give people informative answers to the questions that bother them, to dispel doubts and some common misbeliefs and also to inspire everyone to keep healthy lifestyle.

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