Glaucoma Classification and external resources
The pink rim of disc contains nerve fibers. The white cup is a pit with no nerve fibers. As glaucoma advances, the cup enlarges until it occupies most of the disc area. Courtesy AgingEye Times
ICD-10	H40.-H42.
ICD-9	365
DiseasesDB	5226
eMedicine	oph/578
MeSH	D005901

Human eye cross-sectional view. Courtesy NIH National Eye Institute

Glaucoma is a group of diseases of the optic nerve involving loss of retinal ganglion cells in a characteristic pattern of optic neuropathy. Although raised intraocular pressure is a significant risk factor for developing glaucoma, there is no set threshold for intraocular pressure that causes glaucoma. One person may develop nerve damage at a relatively low pressure, while another person may have high eye pressure for years and yet never develop damage. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness. Image File history File links From http://www. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // H00-H59 - Diseases of the eye and adnexa (H00-H06) Disorders of eyelid, lacrimal system and orbit (H00) Hordeolum and chalazion (H000) Hordeolum and other deep inflammation of eyelid (H001) Chalazion (H01) Other inflammation of eyelid (H010) Blepharitis (H011) Noninfectious dermatoses of eyelid (H02) Other disorders of eyelid (H020) Entropion... // H00-H59 - Diseases of the eye and adnexa (H00-H06) Disorders of eyelid, lacrimal system and orbit (H00) Hordeolum and chalazion (H000) Hordeolum and other deep inflammation of eyelid (H001) Chalazion (H01) Other inflammation of eyelid (H010) Blepharitis (H011) Noninfectious dermatoses of eyelid (H02) Other disorders of eyelid (H020) Entropion... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Image File history File links Human_eye_cross-sectional_view_grayscale. ... Image File history File links Human_eye_cross-sectional_view_grayscale. ... National Institutes of Health Building 50 at NIH Clinical Center - Building 10 The National Institutes of Health (NIH) is an agency of the United States Ministry of Health and Human Services and is the primary agency of the United States government responsible for biomedical and health-related research. ... The National Eye Institute (NEI) is one of the US National Institutes of Health that was established in 1968. ... This article is about the anatomical structure. ... A ganglion cell (or sometimes called a gangliocyte) is a type of neuron located in the retina that receives visual information from photoreceptors via various intermediate cells such as bipolar cells, amacrine cells, and horizontal cells. ... Optic atrophy is a pathological term and somewhat misleading. ... Intraocular pressure (IOP) is the fluid pressure inside the eye. ... For other uses, see Eye (disambiguation). ... This article is about the anatomical structure. ... The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. ... This article is about the visual condition. ...

Glaucoma has been nicknamed "sneak thief of sight" because the loss of visual field often occurs gradually over a long time and may only be recognised when it is already quite advanced. Once lost, this damaged visual field can never be recovered. Worldwide, it is the second leading cause of blindness.^[1] Glaucoma affects one in two hundred people aged fifty and younger, and one in ten over the age of eighty.

Risk factors

A normal range of vision. Courtesy NIH National Eye Institute

The same view with advanced vision loss from glaucoma.

People with a family history of glaucoma have about a six percent chance of developing glaucoma. Diabetics and those of African descent are three times more likely to develop primary open angle glaucoma. Asians are prone to develop angle-closure glaucoma, and Inuit have a twenty to forty times higher risk than caucasians of developing primary angle closure glaucoma. Women are three times more likely than men to develop acute angle-closure glaucoma due to their shallower anterior chambers. Use of steroids can also cause glaucoma. human eyesight two children and ball normal vision Copyright: public domain, US gov. ... human eyesight two children and ball normal vision Copyright: public domain, US gov. ... National Institutes of Health Building 50 at NIH Clinical Center - Building 10 The National Institutes of Health (NIH) is an agency of the United States Ministry of Health and Human Services and is the primary agency of the United States government responsible for biomedical and health-related research. ... The National Eye Institute (NEI) is one of the US National Institutes of Health that was established in 1968. ... human eyesight two children and ball with glaucoma Copyright: public domain, US gov. ... human eyesight two children and ball with glaucoma Copyright: public domain, US gov. ... For other uses, see Inuit (disambiguation). ...

There is increasing evidence of ocular blood flow to be involved in the pathogenesis of glaucoma. Current data indicate that fluctuations in blood flow are more harmful in glaucomatous optic neuropathy than steady reductions. Unstable blood pressure and dips are linked to optic nerve head damage and correlate with visual field deterioration.

A number of studies also suggest that there is a correlation, not necessarily causal, between glaucoma and systemic hypertension (i.e. high blood pressure). In normal tension glaucoma, nocturnal hypotension may play a significant role. On the other hand there is no clear evidence that vitamin deficiencies cause glaucoma in humans, nor that oral vitamin supplementation is useful in glaucoma treatment (Surv Ophthalmol 46:43-55, 2001). For other forms of hypertension, see Hypertension (disambiguation). ...

The main risk factor of glaucoma demonstrated in animal models is recanalization of Hyaloid Canal. Hyaloid Canal and the tunica vascula lentis atrophy in the third trimester of gestation. Occasionally, its system may persist after birth. In some people with some anatomical problem of the eye, intraocular pressure can be rise higher than normal. This condition as Pascal's Rule can make reopenning of hyaloid canal and distiributes the pressure, impact directly to Optic nerve head as a "Locus Minoris". It might causes Glaucomatous Optic Neuropathy. ^[2] Intraocular pressure (IOP) is the fluid pressure inside the eye. ...

Those at risk for glaucoma are advised to have a dilated eye examination at least once a year.^[3] Dilated fundus examination (DFE) is diagnostic procedure that employs the use of mydriatic eye drops to dilate or enlarge the pupil in order to obtain a better view of the internal surface of the eye (i. ...

Diagnosis

Screening for glaucoma is usually performed as part of a standard eye examination performed by ophthalmologists and optometrists. Testing for glaucoma should include measurements of the intraocular pressure via tonometry, changes in size or shape of the eye, and an examination of the optic nerve to look for any visible damage to it, or change in the cup-to-disc ratio. If there is any suspicion of damage to the optic nerve, a formal visual field test should be performed. Scanning laser ophthalmoscopy may also be performed. Traditional Snellen chart used for visual acuity testing. ... Ophthalmology is the branch of medicine which deals with the diseases of the eye and their treatment. ... Optometrists are primary care practitioners for vision and ocular health concerns. ... Intraocular pressure (IOP) is the fluid pressure inside the eye. ... Tonometry is the measurement of tension or pressure[1]. A tonometer is an instrument for measuring tension or pressure[2]. In ophthalmology, tonometry is the procedure eye care professionals perform use to determine the intraocular pressure (IOP), the pressure found inside the eye. ... This article is about the anatomical structure. ... Measurement used in opthalmology to assess the progression of glaucoma. ... Perimetry is the systematic measurement of differential light sensitivity in the visual field by the detection of the presence of test targets on a defined background. ... Scanning laser ophthalmoscopy is a relatively new technology used in the diagnosis of glaucoma. ...

Owing to the sensitivity of some methods of tonometry to corneal thickness, methods such as Goldmann tonometry should be augmented with pachymetry to measure the cornea thickness. While a thicker-than-average cornea can cause a false-positive warning for glaucoma risk, a thinner-than-average cornea can produce a false-negative result. A false-positive result is safe, since the actual glaucoma condition will be diagnosed in follow-up tests. A false-negative is not safe, as it may suggest to the practitioner that the risk is low and no follow-up tests will be done. Tonometry is the measurement of tension or pressure[1]. A tonometer is an instrument for measuring tension or pressure[2]. In ophthalmology, tonometry is the procedure eye care professionals perform use to determine the intraocular pressure (IOP), the pressure found inside the eye. ... Traditional Snellen chart used for visual acuity testing. ...

Treatment

Although intraocular pressure is only one major risk factors of glaucoma, lowering it via pharmaceuticals or surgery is currently the mainstay of glaucoma treatment. In Europe, Japan, and Canada laser treatment is often the first line of therapy. In the U.S., adoption of early laser has lagged, even though prospective, multi-centered, peer-reviewed studies, since the early '90s, have shown laser to be at least as effective as topical medications in controlling intraocular pressure and preserving visual field.

Vascular flow and neurodegenerative theories of glaucomatous optic neuropathy have prompted studies on various therapeutic interventions including nutritional compounds some of which may be regarded by clinicians as safe for use now, others are on trial.

Drugs

Intraocular pressure can be lowered with medication, usually eye drops. There are several different classes of medications to treat glaucoma with several different medications in each class.

Each of these medicines may have local and systemic side effects. Adherence to medication protocol can be confusing and expensive; if side effects occur, the patient must be willing either to tolerate these, or to communicate with the treating physician to improve the drug regimen. Initially, glaucoma drops may reasonably be started in either one or in both eyes.^[4]

Poor compliance with medications and follow-up visits is a major reason for vision loss in glaucoma patients. Patient education and communication must be ongoing to sustain successful treatment plans for this lifelong disease with no early symptoms.

The possible neuroprotective effects of various topical and systemic medications are also being investigated.^{[5] [6] [7]}

Commonly used medications

• Prostaglandin analogs like latanoprost (Xalatan), bimatoprost (Lumigan) and travoprost (Travatan) increase uveoscleral outflow of aqueous humor.
• Topical beta-adrenergic receptor antagonists such as timolol, levobunolol (Betagan), and betaxolol decrease aqueous humor production by the ciliary body.
• Alpha2-adrenergic agonists such as brimonidine (Alphagan) work by a dual mechanism, decreasing aqueous production and increasing uveo-scleral outflow.
• Less-selective sympathomimetics like epinephrine and dipivefrin (Propine) increase outflow of aqueous humor through trabecular meshwork and possibly through uveoscleral outflow pathway, probably by a beta2-agonist action.
• Miotic agents (parasympathomimetics) like pilocarpine work by contraction of the ciliary muscle, tightening the trabecular meshwork and allowing increased outflow of the aqueous humour.
• Carbonic anhydrase inhibitors like dorzolamide (Trusopt), brinzolamide (Azopt), acetazolamide (Diamox) lower secretion of aqueous humor by inhibiting carbonic anhydrase in the ciliary body.
• Physostigmine is also used to treat glaucoma and delayed gastric emptying.

Synthetic prostaglandin analogues are molecules which are manufactured to bind to a prostaglandin receptor. ... Latanoprost (pronounced la-TA-noe-prost) ophthalmic solution is a topical medication used for controlling the progression of glaucoma or ocular hypertension, by reducing intraocular pressure. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... Travoprost ophthalmic solution is a topical medication used for controlling the progression of glaucoma or ocular hypertension, by reducing intraocular pressure. ... Beta blockers (sometimes written as β-blockers) are a class of drugs used for various indications, but particularly for the management of cardiac arrhythmias and cardioprotection after myocardial infarction. ... Timolol maleate is a non-selective beta-adrenergic receptor blocker. ... Betaxolol Ophthalmic is used to treat glaucoma, a condition in which increased pressure in the eye can lead to gradual loss of vision. ... Epinephrine Norepinephrine The adrenergic receptors (or adrenoceptors) are a class of G protein-coupled receptors that are targets of the catecholamines. ... Brimonidine (bri-MOE-ni-deen ) is a drug used to treat glaucoma. ... Sympathomimetics are a class of drugs whose properties mimic those of a stimulated sympathetic nervous system. ... Adrenaline redirects here. ... Dipivefrine (Dipivefrin in the United States) is a prodrug of adrenaline, which is used to treat glaucoma. ... Miosis should not be confused with meiosis, the cellular division process involved in sexual reproduction, or mitosis, the cellular division of somatic body cells. ... A parasympathomimetic is a drug or poison that acts by stimulating or mimicking the parasympathetic nervous system (PNS). ... Pilocarpine is a muscarinic alkaloid obtained from the leaves of tropical American shrubs from the genus Pilocarpus. ... This is an area of tissue located around the base of the cornea, near the ciliary body, and is responsible for draining the aqueous humour from the eye via the anterior chamber (the chamber on the front of the eye covered by the cornea). ... Wikipedia does not yet have an article with this exact name. ... Dorzolamide is a carbonic anhydrase inhibitor. ... Brinzolamide is a carbonic anhydrase inhibitor. ... Acetazolamide, sold under the trade name Diamox®, is a carbonic anhydrase inhibitor that is used to treat glaucoma, epileptic seizures, benign intracranial hypertension and altitude sickness. ... Physostigmine is a parasympathomimetic, specifically, an irreversible cholinesterase inhibitor obtained from the Calabar bean. ...

Compounds in research

Natural compounds

Natural compounds of research interest in glaucoma prevention or treatment include: fish oil and omega 3 fatty acids, bilberries, vitamin E, cannabinoids, carnitine, coenzyme Q10, curcurmin, Salvia miltiorrhiza, dark chocolate, erythropoietin, folic acid, Ginkgo biloba, Ginseng, L-glutathione, grape seed extract, green tea, magnesium, melatonin, methylcobalamin, N-acetyl-L cysteine, pycnogenols, resveratrol, quercetin and salt. ^{[5] [6] [7]} Magnesium, gingko, salt and fludrocortisone, are already used by some physicians. Fish Oil is oil derived from fishes. ... Binomial name Vaccinium myrtillus L. Bilberry is a name given to several species of low-growing shrubs in the genus Vaccinium (family Ericaceae) that bear tasty fruits. ... Tocopherol, or Vitamin E, is a fat-soluble vitamin in eight forms that is an important antioxidant. ... Cannabinoids are a group of terpenophenolic compounds present in Cannabis (Cannabis sativa L). ... This article or section contains information that has not been verified and thus might not be reliable. ... Coenzyme Q (CoQ), also known as ubiquinone or ubiquinol, is a biologically active quinone with an isoprenoid side chain, related in structure to vitamin K and vitamin E. The oxidized structure of CoQ, or Q, is given here: The various kinds of Coenzyme Q can be distinguished by the number... Binomial name Linnaeus Turmeric (Curcuma longa) is a rhizomatous herbaceous perennial plant of the ginger family, Zingiberaceae which is native to tropical South Asia. ... Binomial name Salvia miltiorrhiza Salvia miltiorrhiza (Traditional Chinese: , Simplified Chinese: , pinyin: dÇŽnshÄ“n), also known as Red sage, Chinese sage, tan shen, or dan shen, is a shade-growing perennial flowering plant in the genus Salvia, highly valued for its roots in traditional Chinese medicine (TCM). ... For other uses, see Chocolate (disambiguation). ... Erythropoietin (IPA pronunciation: , alternative pronunciations: ) or EPO is a glycoprotein hormone that is a cytokine for erythrocyte (red blood cell) precursors in the bone marrow. ... Folic acid and folate (the anion form) are forms of the water-soluble Vitamin B9. ... Binomial name Ginkgo biloba L. The Ginkgo (Ginkgo biloba), sometimes also known as the Maidenhair tree, is a unique tree with no living relatives. ... Species Subgenus Panax Section Panax Series Notoginseng Panax notoginseng Series Panax Panax bipinnatifidus Panax ginseng Panax japonicus Panax quinquefolius Panax vietnamensis Panax wangianus Panax zingiberensis Section Pseudoginseng Panax pseudoginseng Panax stipuleanatus Subgenus Trifolius Panax trifolius Ginseng field in Wisconsin Ginseng refers to species within Panax, a genus of 11 species... Glutathione (GSH) is a tripeptide. ... This article is about the fruits of the genus Vitis. ... For other uses, see Tea (disambiguation). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Melatonin, 5-methoxy-N-acetyltryptamine, is a hormone found in all living creatures from algae[1] to humans, at levels that vary in a diurnal cycle. ... Chemical structure of Vitamin B12 The term vitamin B12 (or B12 for short) is used in two different ways. ... Acetylcysteine (rINN) (IPA: ), also known as N-acetylcysteine (abbreviated NAC), is a pharmacological agent used mainly as a mucolytic and in the management of paracetamol overdose. ... Binomial name Pinus pinaster Aiton The Maritime Pine (Pinus pinaster) is a pine native to the western Mediterranean region. ... The cis-isomer of resveratrol Resveratrol is a phytoalexin produced naturally by several plants when under attack by bacteria or fungi. ... Quercetin is a flavonoid that forms the backbone for many other flavonoids, including the citrus flavonoids rutin, hesperidin, naringin and tangeritin. ... R-phrases 36 S-phrases none Flash point Non-flammable Related Compounds Other anions NaF, NaBr, NaI Other cations LiCl, KCl, RbCl, CsCl, MgCl2, CaCl2 Related salts Sodium acetate Supplementary data page Structure and properties n, εr, etc. ... Fludrocortisone acetate is a synthetic corticosteroid with moderate glucocorticoid potency and much greater mineralocorticoid potency. ...

Cannabis

Studies in the 1970s showed that marijuana, when smoked, lowers intraocular pressure.^[8] In an effort to determine whether marijuana, or drugs derived from marijuana, might be effective as a glaucoma treatment, the US National Eye Institute supported research studies from 1978 to 1984. These studies demonstrated that some derivatives of marijuana lowered intraocular pressure when administered orally, intravenously, or by smoking, but not when topically applied to the eye. Many of these studies demonstrated that marijuana — or any of its components — could safely and effectively lower intraocular pressure more than a variety of drugs then on the market. In 2003, the American Academy of Ophthalmology released a position statement asserting that "no scientific evidence has been found that demonstrates increased benefits and/or diminished risks of marijuana use to treat glaucoma compared with the wide variety of pharmaceutical agents now available." The study goes on to say, "studies demonstrated that some derivatives of marijuana did result in lowering of IOP when administered orally, intravenously, or by smoking, but not when topically applied to the eye.The duration of the pressure-lowering effect is reported to be in the range of 3 to 4 hours".^[9][8] A Cannabis sativa plant The drug cannabis, also called marijuana, is produced from parts of the cannabis plant, primarily the cured flowers and gathered trichomes of the female plant. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... The American Academy of Ophthalmology (AAO) is a medical association of ophthalmologists–medical doctors (MDs) specializing in eye care and surgery). ...

The first patient in the United States federal government's Compassionate Investigational New Drug program, Robert Randall, was afflicted with glaucoma and had successfully fought charges of marijuana cultivation because it was deemed a medical necessity (U.S. v. Randall) in 1976.^[10] The Compassionate Investigational New Drug program, or Compassionate IND, is the Investigational New Drug program allowing a limited number of patients to use National Institute on Drug Abuse-provided medical marijuana grown at the University of Mississippi. ... Medical necessity is generally considered that which is reasonable, necessary, and/or appropriate based on evidence-based clinical standards of care. ...

Surgery

Conventional surgery to treat glaucoma makes a new opening in the meshwork. This new opening helps fluid to leave the eye and lowers intraocular pressure.

Main article: Glaucoma surgery

Both laser and conventional surgeries are performed to treat glaucoma. Image File history File links Size of this preview: 643 × 599 pixelsFull resolution (900 × 839 pixel, file size: 63 KB, MIME type: image/jpeg) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Size of this preview: 643 × 599 pixelsFull resolution (900 × 839 pixel, file size: 63 KB, MIME type: image/jpeg) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Glaucoma is a group of diseases affecting the optic nerve that results in vision loss and is frequently characterized by raised intraocular pressure (IOP). ... For other uses, see Laser (disambiguation). ...

Surgery is the primary therapy for those with congenital glaucoma.^[11]

Generally, these operations are a temporary solution, as there is not yet a cure for glaucoma.

Canaloplasty

Canaloplasty is an advanced, nonpenetrating procedure designed to enhance and restore the eye’s natural drainage system to provide sustained reduction of IOP. Canaloplasty utilizes breakthrough microcatheter technology in a simple and minimally invasive procedure. To perform a canaloplasty, a doctor will create a tiny incision to gain access to a canal in the eye. A microcatheter will circumnavigate the canal around the iris, enlarging the main drainage channel and its smaller collector channels through the injection of a sterile, gel-like material called viscoelastic. The catheter is then removed and a suture is placed within the canal and tightened. By opening the canal, the pressure inside the eye will be relieved. [3] [4][5]

Laser surgery

Laser trabeculoplasty may be used to treat open angle glaucoma. It is a temporary solution, not a cure. A 50 μm argon laser spot is aimed at the trabecular meshwork to stimulate opening of the mesh to allow more outflow of aqueous fluid. Usually, half of the angle is treated at a time. Traditional laser trabeculoplasty utilizes a thermal argon laser. The procedure is called argon laser trabeculoplasty or ALT. A newer type of laser trabeculoplasty uses a "cold" (non-thermal) laser to stimulate drainage in the trabecular meshwork. This newer procedure is call selective laser trabeculoplasty or SLT. Studies show that SLT is as effective as ALT at lowering eye pressure. In addition, SLT may be repeated three to four times, whereas ALT can usually be repeated only once.

Laser peripheral iridotomy may be used in patients susceptible to or affected by angle closure glaucoma. During laser iridotomy, laser energy is used to make a small full-thickness opening in the iris. This opening equalizes the pressure between the front and back of the iris, causing the iris to move backward. This uncovers the trabecular meshwork. In some cases of intermittent or short-term angle closure this may lower the eye pressure. Laser iridotomy reduces the risk of developing an attack of acute angle closure. In most cases it also reduces the risk of developing chronic angle closure or gradual adhesion of the iris to the trabecular meshwork.

Trabeculectomy

The most common conventional surgery performed for glaucoma is the trabeculectomy. Here, a partial thickness flap is made in the scleral wall of the eye, and a window opening made under the flap to remove a portion of the trabecular meshwork. The scleral flap is then sutured loosely back in place. This allows fluid to flow out of the eye through this opening, resulting in lowered intraocular pressure and the formation of a bleb or fluid bubble on the surface of the eye. Scarring can occur around or over the flap opening, causing it to become less effective or lose effectiveness altogether. One person can have multiple surgical procedures of the same or different types. Trabeculectomy is a surgical procedure used in the treatment of glaucoma to relieve intraocular pressure by removing part of the eyes trabeculum. ...

Glaucoma drainage implants

There are also several different glaucoma drainage implants. These include the original Molteno implant (1966), the Baerveldt tube shunt, or the valved implants, such as the Ahmed glaucoma valve implant or the ExPress Mini Shunt and the later generation pressure ridge Molteno implants. These are indicated for glaucoma patients not responding to maximal medical therapy, with previous failed guarded filtering surgery (trabeculectomy). The flow tube is inserted into the anterior chamber of the eye and the plate is implanted underneath the conjunctiva to allow flow of aqueous fluid out of the eye into a chamber called a bleb.

• The first-generation Molteno and other non-valved implants sometimes require the ligation of the tube until the bleb formed is mildly fibrosed and water-tight^[12]This is done to reduce postoperative hypotony -- sudden drops in postoperative intraocular pressure (IOP).
• Valved implants such as the Ahmed glaucoma valve attempt to control postoperative hypotony by using a mechanical valve. Studies show that in severe cases of glaucoma, double plate Molteno implants are associated with lower mean IOP in the long term compared to the Ahmed glaucoma valve ^[13]
• Second and third generation Molteno implants incorporate a biological valve and studies show considerable improvement in postoperative outcome over the older style Ahmed and Molteno implants.

The ongoing scarring over the conjunctival dissipation segment of the shunt may become too thick for the aqueous humor to filter through. This may require preventive measures using anti-fibrotic medication like 5-fluorouracil (5-FU) or mitomycin-C (during the procedure), or additional surgery. The aqueous humour is the clear, watery fluid that fills the complex space in the front of the eye which is bounded at the front by the cornea and at the rear by the front surface or face of the vitreous humour. ... Fluorouracil (5-FU) is a drug that is used in the treatment of cancer. ... The mitomycins are a family of aziridine-containing natural products isolated from One of these compounds, mitomycin C, finds use as a chemotherapeutic agent by virtue of its antitumour antibiotic activity. ...

Major studies

• Advanced Glaucoma Intervention Study (AGIS) - large American National Eye Institute (NEI) sponsored study designed "to assess the long-range outcomes of sequences of interventions involving trabeculectomy and argon laser trabeculoplasty in eyes that have failed initial medical treatment for glaucoma." It recommends different treatments based on race.
• Early Manifest Glaucoma Trial (EMGT) -Another NEI study found that immediately treating people who have early stage glaucoma can delay progression of the disease.
• Ocular Hypertension Treatment Study (OHTS) -NEI study findings: "...Topical ocular hypotensive medication was effective in delaying or preventing onset of Primary Open Angle Glaucoma (POAG) in individuals with elevated Intraocular Pressure (IOP). Although this does not imply that all patients with borderline or elevated IOP should receive medication, clinicians should consider initiating treatment for individuals with ocular hypertension who are at moderate or high risk for developing POAG."
• Blue Mountains Eye Study "The Blue Mountains Eye Study was the first large population-based assessment of visual impairment and common eye diseases of a representative older Australian community sample." Risk factors for glaucoma and other eye disease were determined.

Linked with Alzheimer's Disease.

ScienceDaily (Aug. 7, 2007) — UK scientists have shown for the first time that key proteins involved in Alzheimer's disease are also implicated in glaucoma, the major cause of irreversible blindness worldwide. Research carried out at the UCL Institute of Ophthalmology and funded by the Wellcome Trust has also shown that novel drugs being trialled for Alzheimer's disease which target this protein may be used to treat glaucoma.

The research team has developed a new technology for visualising nerve cell damage in the retina, known as Detection of Apoptosing Retinal Cells. Using this technology, they demonstrated that the protein beta-amyloid, which causes the so-called "plaque" lesions in the brains of Alzheimer's patients, also leads to nerve cell death in the retina. The research is published online today in the journal Proceedings of the National Academy of Sciences of the USA.

"We've seen for the first time that there is a clear link between what causes Alzheimer's disease and one of the basic mechanisms behind glaucoma," says Dr Francesca Cordeiro from University College London, who led the study. Dr Cordeiro is also a consultant ophthalmologist at the Western Eye Hospital, London, specialising in glaucoma. "However, this doesn't mean that everyone with Alzheimer's will develop glaucoma or vice versa. Glaucoma has a number of risk factors."

Glaucoma affects over half a million in the UK and as many as 65 million people worldwide. Little is know about what exactly causes the disease, which causes damage to the optic nerve in the eye; although the disease is traditionally attributed to increased pressure in the eye (known as "intraocular pressure", and clinical treatments attempt to lower this pressure). However a significant number of patients continue to lose vision despite their pressure being well controlled. The new research opens up a new avenue of treatment in glaucoma which does not involve treating intraocular pressure.

Dr Cordeiro and colleagues have shown that drugs which work to prevent the build up of the beta-amyloid protein in Alzheimer brains can be used to treat glaucoma in animal models. One such drug, Bapineuzumab, is already being used in clinical trials to treat Alzheimer's patients by pharmaceutical companies Elan in Dublin and Wyeth in the US. However, the UK researchers have shown that when combined with two other novel Alzheimer's treatments, the effects on glaucoma are even stronger.

"We are trying a new approach which has never been tried before, not even to treat Alzheimer's disease," says Dr Cordeiro. "Our success in treating glaucoma in the lab by combining different Alzheimer's treatments represents a brand new treatment strategy."

Research carried out previously by Dr Cordeiro and colleagues and also funded by the Wellcome Trust suggested that the retina can provide a window into the brain, allowing doctors to diagnose Alzheimer's disease by looking for evidence of nerve cell death. Alzheimer's disease is the most common form of dementia. Nearly 700,000 people in the UK suffer from dementia and this is expected to exceed one million people by 2025(2).

"Many even within medicine fail to realise that the retina, commonly examined by high street opticians when they look at the back of the eye, is actually an extension of brain tissue, travelling down the optic nerve into the back of the eye," she says. " High street opticians have been routinely looking at the brain in a more direct way than has been possible by high tech brain scanners such as MRI and CAT."

Now, Dr Cordeiro believes that this knowledge may mean that the eye could also be used to test potential treatments for Alzheimer's disease.

"Since we have shown that drugs for Alzheimer's disease can tackle glaucoma, then potentially we could use damaged retina to screen Alzheimer's drugs that target beta-amyloid build up."

Adapted from materials provided by Wellcome Trust, via EurekAlert!, a service of AAAS.

Classification of glaucoma

Glaucoma has been classified into specific types:^[14]

Primary glaucoma and its variants (H40.1-H40.2)

• Primary glaucoma

• Primary open-angle glaucoma, also known as chronic open-angle glaucoma, chronic simple glaucoma, glaucoma simplex
• Low-tension glaucoma
• Primary angle-closure glaucoma, also known as primary closed-angle glaucoma, narrow-angle glaucoma, iris-block glaucoma, acute congestive glaucoma

• Acute angle-closure glaucoma
• Chronic angle-closure glaucoma
• Intermittent angle-closure glaucoma
• Superimposed on chronic open-angle closure glaucoma (combined mechanism)

• Variants of primary glaucoma

• Pigmentary glaucoma
• Exfoliation glaucoma, also known as pseudoexfoliative glaucoma or glaucoma capsulare

Primary open-angle glaucoma - This is caused by trabecular blockage which is where the Aqueous humor in the eye drains out. Because the microscopic passage ways are blocked, the pressure builds up in the eye and causes imperceptable very gradual vision loss. Peripheral vision is affected first but eventually the entire vision will be lost if not treated. Diagnosis is made by looking for cupping of the optic nerve. The treatment's goal is to release the fluid by opening uveoscleral passageways, which are acted upon by prostoglandin agonists. Beta blockers such as timolol, alpha 2 agonist, work by decreasing aqueous formation. Carbonic anhydrase inhibitors decrease bicarbonate formation from ciliary processes in the eye, thus decreasing formation of Aqueous humor. Parasympathetic analogs are drugs that work on the trabecular outflow by opening up the passageway and constricting the pupil.

Primary closed-angle glaucoma - This is caused by sudden blockage of the flow across the pupil. Pressure will rapidly build up in the eye causing pain and redness. Vision becomes blurred and halos are seen around bright objects. Accompanying symptoms include headache and vomiting. Diagnosis is made from obvious physical findings: pupils dilated, cornea swollen, reduced vision, redness, pain. Treatment is no longer focused on trabecular or uveoscleral passageways. The formation of fluid can be temporarily treated with carbonic anhydrase inhibitors which act on the ciliary process. But the patient will need surgery or laser treatment.

Developmental glaucoma (Q15.0)

• Developmental glaucoma

• Primary congenital glaucoma
• Infantile glaucoma
• Glaucoma associated with hereditary of familial diseases

Secondary glaucoma (H40.3-H40.6)

• Secondary glaucoma

• Inflammatory glaucoma

• Uveitis of all types
• Fuchs heterochromic iridocyclitis

• Phacogenic glaucoma

• Angle-closure glaucoma with mature cataract
• Phacoanaphylactic glaucoma secondary to rupture of lens capsule
• Phacolytic glaucoma due to phacotoxic meshwork blockage
• Subluxation of lens

• Glaucoma secondary to intraocular hemorrhage

• Hyphema
• Hemolytic glaucoma, also known as erythroclastic glaucoma

• Traumatic glaucoma

• Angle recession glaucoma: Traumatic recession on anterior chamber angle
• Postsurgical glaucoma

• Aphakic pupillary block
• Ciliary block glaucoma

• Neovascular glaucoma
• Drug-induced glaucoma

• Corticosteroid induced glaucoma
• Alpha-chymotrypsin glaucoma. Postoperative ocular hypertension from use of alpha chymotrypsin.

• Glaucoma of miscellaneous origin

• Associated with intraocular tumors
• Associated with retinal deatchments
• Secondary to severe chemical burns of the eye
• Associated with essential iris atrophy
• Toxic Glaucoma ^[15]

Absolute glaucoma (H44.5)

• Absolute glaucoma

See also

• List of eye diseases and disorders
• Ocular hypertension
• Glaucoma valves
• Mansour F. Armaly
• Laszlo Z. Bito
• Charles D. Phelps
• American Glaucoma Society

This is a partial list of human eye diseases and disorders. ... Ocular hypertension (OHT) is intraocular pressure higher than normal in the absence of optic nerve damage or visual field loss . Current consensus in ophthalmology defines normal introcular pressure (IOP) as that between 10 mmHg and 21 mmHg . Elevated IOP is the most important risk factor for glaucoma, so those with... A glaucoma valve is a medical shunt used in the treatment of glaucoma to reduce the eyes intraocular pressure (IOP). ... Mansour F. Armaly Mansour F. Armaly (February 25, 1927-August 19, 2005) was a physician who was globally recognized as a pioneering researcher in the modern medical treatment of glaucoma. ... Laszlo Z. Bito László Z. Bitó (born 7 September 1934, Budapest) is a physiologist and a writer. ... Charles D. Phelps, M.D., as department head, Department of Ophthalmology, University of Iowa, 1984 Charles Dexter Phelps (September 16, 1937-September 13, 1985) was a prominent American medical doctor, professor, and researcher in the field of ophthalmology, specializing in glaucoma. ... The American Glaucoma Society is a subspecialty society in ophthalmology that promotes education and research about glaucoma among physicians and scientists. ...

References

1. ^ "Global data on visual impairment in the year 2002" Bulletin of the World Health Organization Volume 82, Number 11, November 2004, 811-890
2. ^ Intraocular pressure measure on normal eyes by Pardianto G et al., in Mimbar Ilmiah Oftalmologi Indonesia.2005;2: 78-9.
3. ^ National Institutes of Health
4. ^ [ http://www.biomedcentral.com/1471-2415/7/17 Interpretation of uniocular and binocular trials of glaucoma medications]
5. ^ ^{a b} Ritch R. Natural compounds: evidence for a protective role in eye disease. Can J Ophthalmol. 2007 Jun;42(3):425-38.PMID 17508040
6. ^ ^{a b} Tsai JC, Song BJ, Wu L, Forbes M. Erythropoietin: a candidate neuroprotective agent in the treatment of glaucoma. J Glaucoma. 2007 Sep;16(6):567-71. PMID 17873720
7. ^ ^{a b} Mozaffarieh M, Flammer J. Is there more to glaucoma treatment than lowering IOP? Surv Ophthalmol. 2007 Nov;52 Suppl 2:S174-9. PMID 17998043
8. ^ ^{a b} American Academy of Ophthalmology. Complementary Therapy Assessment: Marijuana in the Treatment of Glaucoma. Retrieved August 2, 2006.
9. ^ Complementary Therapy Assessments : American Academy of Ophthalmology
10. ^ Irvin Rosenfeld and the Compassionate IND - Medical Marijuana Proof and Government Lies
11. ^ "Glaucoma, Congenital: GLC3 Buphthalmos." OMIM - Online Mendelian Inheritance in Man. Accessed October 17, 2006.
12. ^ Molteno AC, Polkinghorne PJ, Bowbyes JA. The vicryl tie technique for inserting a draining implant in the treatment of secondary glaucoma. Aust N Z J Ophthalmol. 1986 Nov;14(4):343-54 [1]
13. ^ Ayyala RS, Zurakowski D et al. Comparison of double-plate Molteno and Ahmed glaucoma valve in patients with advanced uncontrolled glaucoma. Ophthalmic Surg Lasers. 2002 Mar-Apr;33(2):94-101.[2].
14. ^ Paton D, Craig JA. "Glaucomas. Diagnosis and management." Clin Symp. 1976;28(2):1-47. PMID 1053095.
15. ^ Some difficulties on Glaucoma by Pardianto G et al., in Mimbar Ilmiah Oftalmologi Indonesia.2006;3: 48-9.

External links

• Glaucoma Resource Guide from the National Eye Institute (NEI).
• Global Association of International Glaucoma Societies - featuring a hymn about the successful treatment of glaucoma
• EUROPEAN GLAUCOMA SOCIETY
• Glaucoma Research Foundation
• Glaucoma - What is Glaucoma?. NLM. Retrieved on 2007-04-21. video
• Nonprofit Foundation for Glaucoma
• National Glaucoma Research
• Asia Ophthalmology Center
• DJO | Digital Journal of Ophthalmology
• Lions Eye Institute, Perth, Australia
• Mar 2008 BBC article on diagnosis advances
• Glaucoma Associates Of New York