Early detection and treatment by an ophthalmologist can prevent vision loss.
The most common type of glaucoma, open-angle, often shows no symptoms at first, which is why it’s important for patients to have regular eye exams with a specialist.

Symptoms of glaucoma can include:

• Slow loss of peripheral (side) vision
• Sudden, severe pain in one eye
• Reduced or cloudy vision
• Nausea or vomiting
• Halos around lights
• Redness or swelling of the eye
• Sensitivity to light
• Cloudy appearance in the front of the eye

Eye specialists can diagnose glaucoma through a comprehensive eye exam. The exam might include several of the following tests:

• Vision tests, including automated visual field tests to check peripheral (side) vision
• Dilated eye test to examine inside the eye
• Tonometry, a painless test that measures pressure inside the eye
• Slit-lamp exam to look at structures inside the eye, such as the retina, lens, cornea, iris, and anterior chamber
• Gonioscopy using a special lens to check the drainage angle for abnormalities
• Imaging, such as fundus photography, of the inside of the eye to examine the optic nerve and measure any changes over time
• Indirect ophthalmoscopy to evaluate the peripheral retina
  
  

Eye pressure is measured in millimeters of mercury (mm Hg). Normal eye pressure typically ranges from 10 to 22 mmHg. Pressure higher than 22 mmHg can indicate an increased risk for developing glaucoma. However, glaucoma can develop even when eye pressure measures in the normal range. 

In a healthy eye, a clear fluid (aqueous humor) fills the front of the eye and normally flows in and out through channels where the iris and cornea meet. Because glaucoma often results from high intraocular pressure, anything that blocks or slows the flow of this fluid increases pressure.

The major types of glaucoma are:

• Open-angle glaucoma: More than 90 percent of adults with glaucoma have this type. In open-angle glaucoma, fluid inside the eye pressure increases slowly over a long time, and patients often do not notice a change. As pressure on the optic nerve increases, it can damage the nerve and cause vision loss such as blind spots.
• Angle-closure glaucoma: Also known as closed-angle glaucoma, this type occurs when the fluid suddenly becomes blocked, leading to a quick, dramatic pressure increase inside the eye. Angle-closure glaucoma usually causes immediate, noticeable symptoms such as severe eye pain and blurry vision. This type of glaucoma is a medical emergency and requires immediate treatment to prevent blindness.
• Low- or normal-tension glaucoma: Some people with normal eye pressure can develop this type of glaucoma, a form of open-angle glaucoma.
• Congenital glaucoma: Some babies are born with a defect in the eye that slows the normal fluid drainage. Congenital glaucoma usually causes noticeable symptoms and signs very early, and prompt surgery provides children with an excellent chance for good vision.
• Secondary glaucoma: Either open- or closed-angle glaucoma can develop as a result of a known cause, such as another eye disease, a medical condition, an injury, or certain medications. Some types of secondary glaucoma include:
• Pigmentary glaucoma: In younger, nearsighted patients, pigment from the iris can dislodge and clog the eye’s internal drainage channels, leading to build up of pressure inside the eye and a secondary glaucoma.
• Traumatic glaucoma: Eye injuries can damage and block the fluid drainage system in the eye, which increases eye pressure and can lead to glaucoma. Traumatic glaucoma can develop immediately after an injury or even years later, so ongoing monitoring is important.

Routine dilated eye examinations with an eye specialist are the best way to detect glaucoma and can help prevent vision loss. The  Ophthalmologists recommends having an eye examination:

• Every 5 to 10 years for people under age 40
• Every 2 to 4 years for people ages 40 to 54
• Every 1 to 3 years for people ages 55 to 64
• Every 1 to 2 years for people age 65 and older or who have glaucoma risk factors
  
  

These self-care steps can help you detect glaucoma in its early stages, which is important in preventing vision loss or slowing its progress.

·        Get regular dilated eye examinations. Regular comprehensive eye exams can help detect glaucoma in its early stages, before significant damage occurs. As a general rule, the American Academy of Ophthalmology recommends having a comprehensive eye exam every five to 10 years if you're under 40 years old; every two to four years if you're 40 to 54 years old; every one to three years if you're 55 to 64 years old; and every one to two years if you're older than 65. If you're at risk of glaucoma, you'll need more frequent screening. Ask your doctor to recommend the right screening schedule for you.

·        Know your family's eye health history. Glaucoma tends to run in families. If you're at increased risk, you may need more frequent screening.

·        Exercise safely. Regular, moderate exercise may help prevent glaucoma by reducing eye pressure. Talk with your doctor about an appropriate exercise program.

·        Take prescribed eyedrops regularly. Glaucoma eyedrops can significantly reduce the risk that high eye pressure will progress to glaucoma. To be effective, eyedrops prescribed by your doctor need to be used regularly even if you have no symptoms.

·        Wear eye protection. Serious eye injuries can lead to glaucoma. Wear eye protection when using power tools or playing high-speed racket sports in enclosed courts.

The causes of open-angle glaucoma are unknown. Causes for other types of glaucoma include:

• Dilating eye drops
• Certain medications such as corticosteroids
• Eye diseases
• Other conditions such as diabetes
• Previous eye injury or eye surgery
• Congenital (present since birth) defect

Several factors can increase a person’s risk of developing glaucoma, such as:

• Advanced age
• Extreme nearsightedness
• African or Hispanic ancestry
• Extremely low blood pressure 
• Diabetes (in some cases)
• Family history of glaucoma
• Thin cornea (clear layer covering the front of the eye)

Unfortunately glaucoma is typically associated with painless and progressive loss of vision that may escape detection by the patient. This once again stresses the importance of a thorough eye history and examination, especially in patients with a family history of glaucoma. Only one type of glaucoma called angle-closure glaucoma is associated with a red, painful eye with blurred vision and even possibly nausea and vomiting. This is due to very high pressures resulting from a block in the drainage system of the eye. Most patients at risk for this type of glaucoma have structural differences in their eye which could be identified prior to an attack and preventative treatment could be performed. Rarely do patients with other types of glaucoma develop pressure high enough to have pain and redness.

Symptoms

The signs and symptoms of glaucoma vary depending on the type and stage of your condition. For example:

Open-angle glaucoma

·        Patchy blind spots in your side (peripheral) or central vision, frequently in both eyes
·        Tunnel vision in the advanced stages

Acute angle-closure glaucoma

·        Severe headache
·        Eye pain
·        Nausea and vomiting
·        Blurred vision
·        Halos around lights
·        Eye redness

The genetic inheritance of glaucoma is still unclear. However, a family history of glaucoma has been found in up to 50% of patients with the most common type of glaucoma, known as primary open-angle glaucoma. One type of glaucoma occurs in people who have had a history of being hit in the eye (e.g. soccer ball). Not only can they get a rise in pressure initially after the injury, but they also may develop glaucoma years later. All of these things stress the importance of regular eye exams.

Glaucoma is a group of eye conditions that damage the optic nerve, the health of which is vital for good vision. This damage is often caused by an abnormally high pressure in your eye. Glaucoma is one of the leading causes of blindness for people over the age of 60. It can occur at any age but is more common in older adults.

Many forms of glaucoma have no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is at an advanced stage. Because vision loss due to glaucoma can't be recovered, it's important to have regular eye exams that include measurements of your eye pressure so a diagnosis can be made in its early stages and treated appropriately. If glaucoma is recognized early, vision loss can be slowed or prevented. If you have the condition, you'll generally need treatment for the rest of your life.