Elsevier

The Lancet

Volume 363, Issue 9422, 22 May 2004, Pages 1711-1720
The Lancet

Seminar
Primary open-angle glaucoma

https://doi.org/10.1016/S0140-6736(04)16257-0Get rights and content

Summary

Primary open-angle glaucoma is a progressive optic neuropathy and, perhaps, the most common form of glaucoma. Because the disease is treatable, and because the visual impairment caused by glaucoma is irreversible, early detection is essential. Early diagnosis depends on examination of the optic disc, retinal nerve fibre layer, and visual field. New imaging and psychophysical tests can improve both detection and monitoring of the progression of the disease. Recently completed long-term clinical trials provide convincing evidence that lowering intraocular pressure prevents progression at both the early and late stages of the disease. The degree of protection is related to the degree to which intraocular pressure is lowered. Improvements in therapy consist of more effective and better-tolerated drugs to lower intraocular pressure, and more effective surgical procedures. New treatments to directly treat and protect the retinal ganglion cells that are damaged in glaucoma are also in development.

Section snippets

Epidemiology

It is estimated that glaucoma affects more than 66 million individuals worldwide with at least 6·8 million bilaterally blind.1 Vision loss caused by glaucoma is irreversible, and glaucoma is the second leading cause of blindness in the world. Of the many types of glaucoma, primary open-angle glaucoma is perhaps the most common, particularly in populations of European and African ancestry.2, 3 The disease is the leading cause of blindness in African-Americans.

In the USA, more than 7 million

Aqueous humour secretion and drainage

Intraocular pressure is regulated by a balance between the secretion and drainage of aqueous humour (figure 1). This fluid is secreted posterior to the iris by the ciliary body and then flows anteriorly to the anterior chamber. Aqueous humour provides nutrients to the iris, lens, and cornea. It exits the eye into the venous circulation via the trabecular meshwork and independently through the uveoscleral outflow pathway.

The optic nerve and inner retina

Axons of retinal ganglion cells comprise the retinal nerve fibre layer, the

Pathophysiology

Glaucoma is a neurodegenerative disease characterised by the slow, progressive degeneration of retinal ganglion cells.5 With glaucoma, the width of the neuroretinal rim decreases with concomitant enlargement of the cup. Other optic neuropathies usually result in pallor of the optic nerve head but, for unknown reasons, rarely show enlargement of the optic disc cup. Glaucomatous neuronal death is not limited to changes in the retinal ganglion cell axons, soma, and dendrites;6 neurons in the

Diagnosis

Primary open-angle glaucoma is a chronic, generally bilateral, but often asymmetrical, disease that is characterised by progressive damage of the optic nerve as shown by changes in the optic disc, retinal nerve fibre layer, or visual field. The disease has an adult onset, with open anterior chamber angles of normal appearance and an absence of other known explanations for the change in the optic nerve. If detected early, disease progression can frequently be arrested or slowed with medical and

Goals of glaucoma management

As described in the Preferred Practice Patterns of the American Academy of Ophthalmology70 and other guidelines, glaucoma care aims to enhance the patient's health and quality of life by preserving visual function without causing untoward effects from treatment. Specific goals are: (1) to document the status of optic nerve on presentation and during follow-up by assessment of the appearance of the optic disc, retinal nerve fibre layer, or both, and assessment of the visual field; (2) estimation

Conclusion

The worldwide prevalence of primary open-angle glaucoma is increasing. Although the pathophysiology of glaucoma is still not well understood, results of large-scale long-term clinical trials have shown that reduction of intraocular pressure prevents the progression of early and late glaucoma. These findings clearly show the importance of early diagnosis to initiate pressure-lowering treatment and early detection of progression to advance this treatment.

Search strategy and selection criteria

We systematically searched MEDLINE with terminology relating to primary open-angle glaucoma discussed in this review. Keywords used were glaucoma, open-angle glaucoma, primary open-angle glaucoma, glaucoma blindness, ocular hypertension. Articles were reviewed up to June, 2003, and studies reported in full and in abstract form have been reported.

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