The optic neuropathy known as glaucoma changes the optic nerve head and nerve fiber layer in a distinctive way. Characteristic visual field impairments appear as the condition worsens. It is a medical condition, to put it simply, that is characterized by excessive intraocular pressure, cupping, atrophy of the optic nerve head, and loss of vision which are the clinical symptoms of glaucoma. 

In the United States, Africa, and India, glaucoma is the second most typical cause of blindness. In the USA, glaucoma affects roughly 3 million people, 1 million of whom are unaware that they have the disease, and 80,000 of whom are blind as a result of it. Glaucoma affects 11.2 million Indians who are 40 years of age or older. Estimates place the prevalence of POAG, one of the glaucoma forms, at 6.48 million. There are 2.54 million people with other kinds of PACG in India.

Structure of eye-

Eye has 3 chambers – anterior, posterior and vitreous. Intraocular pressure is maintained by balance of inflow and outflow of aqueous humor produced by the ciliary body. It is this fluid that nourishes the transparent structures of the eye.

Groups at risk of glaucoma-

• Elderly people
• African-Americans
• Individuals with-

• Increased Intraocular pressure
• Those having first degree family members with glaucoma
• Ocular hypertension
• High myopia
• Diabetes

Types of glaucoma-

• Primary open angle glaucoma (POAG)
• Primary angle closure glaucoma (PACG)
• Congenital glaucoma
• Childhood glaucoma
• Secondary glaucoma

 

 

FLOWCHART DEPICTING TYPES OF GLAUCOMA 

Characteristics of primary open angle glaucoma-

• Most common type 
• 60-70% cases 
• Bilateral in both eyes
• Not always symmetric
• Optic nerve and visual field damage
• Adult-onset
• Open, normal appearing anterior chamber angles of eyes
• Absence of secondary causes such as trauma 

Etiology of primary open angle glaucoma-

Aqueous humor is produced by the ciliary body in a typical eye and passes through the pupil and anterior chamber before being emptied through the trabecular meshwork and a canal that leads to the venous system. However, increased trabecular meshwork resistance to aqueous humor outflow occurs in primary open angle glaucoma, which raises intraocular pressure and damages vulnerable patients' visual nerves. Most individuals do not seek therapy because there are no symptoms in the early stages of the disease. But by the time visual loss is noticed by patients, it is markedly high. Speed of progression of disease varies with patients and if left untreated, people affected may suffer optic nerve atrophy and blindness.

Characteristics or Symptoms of other glaucoma –

Angle closure glaucoma	Congenital glaucoma	Childhood glaucoma	Secondary glaucoma
Second most common type	Present in infants	Present in childhood or adolescence	Occurs in patients with ocular conditions
Cause is appositional closure of drainage angle of eye	More common in male infants , may be unilateral or bilateral	Asymptomatic in early stages of disease	Causes are trauma, uveitis, chronic steroid use, diabetic retinopathy and ocular vascular occlusion
Due to angle closure, aqueous humor does not leave the eye	Appear as tearing, photophobia, enlarged eye or hazed cornea	Causes total optic nerve atrophy and blindness	Management of intraocular pressure and underlying ocular condition should be done

 

EYES DEPICTING GLAUCOMA TYPES  OR WHAT DOES GLAUCOMA VISION LOOKS LIKE

 

Investigations-

• Done by ophthalmologist
• Visual acuity test
• Perimetry test
• Tonometry test

 

Clinical features for screening of main types of glaucoma along with treatments-

POAG	PACG
Painless fall of vision, patchy blind spots in both eyes, tunnel vision in advanced disease	Ocular pain with cloudy cornea, nausea, vomiting, blurring of vision
Frequent Change of near vision glasses	Hypermetropia complaining of headaches
Inappropriate near vision demand for age	Frequent headaches
Myopia	Headaches while watching movie in cinema hall
Diabetes mellitus	History of halos around lights
Family history	Red eye
Treatment is medication, laser and surgery	Treatment is medication, iridotomy with laser

 

PICTORIAL REPRESENTATION OF NORMAL EYE AND EYE WITH GLAUCOMA

 

Prevention of glaucoma-

• Get regular dilated eye examinations
• Know family eye health history
• Exercise safely
• Take prescribed eye drops regularly
• Wear eye protection or sunglasses regularly to ward off dust and sunlight from eyes

 

Summary-

A series of eye conditions known as glaucoma affect the optic nerve, whose health is essential for clear vision. High pressure in the eyes that is not normal often results in this injury. Glaucoma causes nerve damage and vision loss that cannot be repaired. But if it is detected in its earliest stages, there are treatments that can stop its progression and avoid visual loss. 

The pressure inside the eye is reduced by all treatments. Options for treatment of glaucoma include oral glaucoma medications, ocular drops, laser treatments, and traditional surgery. Both laser surgery and traditional surgery are available as surgical options. 

Acute angle closure glaucoma is a medical emergency because it might cause permanent blindness if it is not addressed. The risk factors for glaucoma are high blood pressure, increased pressure in the eye and family history. It has a gradual or sudden onset. Its symptoms are vision loss, eye pain, mild dilated pupils, redness of eye and nausea. Its differential diagnosis is keratitis , uveitis , trauma and conjunctivitis. 

About 70 million people have glaucoma globally. Some glaucoma tests are tonometry to measure inner eye pressure, dilated eye examination to observe shape and  color of optic nerve, perimetry which determines complete field of vision, pachymetry to see thickness of cornea, gonioscopy to see angle in eye where iris meets cornea and nerve fiber analysis to see thickness of nerve fiber layer. 

There are some glaucoma variants also like toxic glaucoma, developmental glaucoma, pigmentary glaucoma, exfoliation glaucoma etc. Glaucoma is an umbrella term for eye conditions and includes many other types and variants and is associated with many syndromes. 

 

Fact Check:

Frequency in India: Irreversible blindness is mostly caused by glaucoma, with 12 million Indians affected and nearly 1.2 million people blind. Approximately 90% of the cases remain undiagnosed.

PGC Resolution: 

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