In most cases, glaucoma has no symptoms because the disease develops slowly, and loss of peripheral vision is rarely noticed. By the time an individual experiences decreased vision, the disease is far advanced. Early warning signs of glaucoma are rare. Hence one must have regular eye examinations as one comes close to 40 years of age.

An acute form of glaucoma (acute angle closure) may develop severe symptoms because of a sudden rise in intra ocular pressure. Such patients may experience:

• Blurred vision, especially at night
• Halos or rainbows around lights
• Severe headaches or eye pain
• Nausea

It is at times difficult to diagnose a disease that has no symptoms until it far advanced. And because symptoms in the early stages of glaucoma are uncommon it is uncommon for people to present themselves for a thorough eye examination until too late.

Although glaucoma is most common in adults over the age of 40, susceptibility is not determined by age alone. A genetic predisposition of those with a family history of glaucoma exists. If a first degree relative -mother, father, sister, brother has glaucoma then the risk of developing glaucoma increases TEN times. Those at greater risk for glaucoma may fit one or more of the following criteria:

• Age over 40 years of age
• Glaucoma in the family
• Have diabetes/ thyroid disease / hypertension
• Have received steroid containing preparations: tablets/ drops/ ointments/ puffs/ injections
• See rainbow-coloured rings around bright light
• Rapid change of glasses
• Taking medication for sleep / anxiety / depression / asthma/ parkinsonism
• Injury to the face /eye
• Myopia
• Have headaches.

The common types of glaucoma are:-

• Open Angle Glaucoma: The drainage systems become clogged by deposits causing a gradual backflow of fluid with accumulation within the eye. Or there can be increased fluid production (mustard oil contamination), more that than what can be tackled by the outflow channels.

• Closed Angle Glaucoma: Here there is resistance to flow within different compartments of the eye at the level of the pupil.

The open and closed type represent the two basic types of glaucoma. As one who has glaucoma it’s important to know what type of glaucoma one has (open/closed) because they may differ in the way they manifest. More importantly, it is essential to know the type of glaucoma one has because treatment varies depending on the type of glaucoma.

The open type of glaucoma is usually treated first with drops failing which a glaucoma surgery may need to be done. The closed type of glaucoma is usually treated with a laser iridotomy. If required, medication in the form of drops may also be required (depending on the severity). When these don’t work a glaucoma surgery may need to be considered.

Glaucomas can be further classified as primary or secondary:-

• Primary glaucomas are usually not associated with an obvious systemic or other eye related disorder that could cause glaucoma. Usually, primary glaucomas affect both eyes and can have a predisposition to affect other family members. Secondary glaucomas are often associated with systemic or other eye related disorders that can cause glaucoma. They may affect one or both eyes and may or may not predispose other family members to develop glaucoma.

• In Secondary glaucoma usually there is an inciting condition like an injury, certain drugs like steroid containing preparations in any form, phenothiazine tranquilizers, anti depressants, anti histamincs, anti spasmolytics, antacids like cimetidine and ranitidine, antiparkinsonism drugs, sedatives and stimulants, sulfa containing drugs, sympathomimetic agents like salbutamol and ephedrine and mydriatics amongst others (in those predisposed), hemorrhages, tumors, and inflammations amongst others which can sometimes block outflow channels in the eye.

This may increase the eye pressure and lead to (secondary) glaucoma. The only known type of secondary glaucoma associated with an increased fluid production is due to mustard oil contamination. The toxin produces excess aqueous humor, more that than what can be tackled by the outflow channels. Glaucoma associated with mustard oil contamination is called “Epidemic dropsy”. Delhi has had several such epidemics.

Childhood Glaucomas (developmental glaucomas): Here the "outflow channels are poorly manufactured. This type of defect is seen in congenital glaucomas, where the drainage openings are abnormal from birth.

Developmental glaucomas can be further classified as primary congenital glaucoma where there is no obvious systemic or eye related abnormality as the causative factor. Since a child’s eye is more elastic than an adult's, when the pressure inside the eye increases, the easily stretchable eye of the child may enlarge. This can typically happen up to three years of age. With raised eye pressure’s, the front of the eye may become cloudy like fog on a windshield. The child may become sensitive to light and may have persistent watering. Though rare it still not so uncommon. It’s important to remember that large eyes may not always be beautiful eyes. They can at times harbor a glaucoma.

Secondary developmental glaucomas usually have additional systemic or eye related abnormalities which cause the glaucoma (Axenfeld Rieger syndrome, Aniridia, Sturge Weber syndrome etc).

The diagnosis of GLAUCOMA can often be missed if eye pressure is the only criteria.

Diagnosis is based on the TOPG test.

• Tonometry: Measuring the fluid pressure inside the eye with an instrument using blue light.

• Ophthalmoscopy to look at the optic nerve. This is supplemented with photographs and imaging devices.

• Perimetry: Measures a person’s side or peripheral vision. Lost peripheral vision may mean a person has glaucoma.

• Gonioscopy to assess the angle outflow structures. Gonioscopy is the only way to confirm what kind of glaucoma one has. The open type of glaucoma is usually treated first with drops failing which a glaucoma surgery may need to be done. The closed type of glaucoma is usually treated with a laser iridotomy and drops. When these don't work a glaucoma surgery may need to be considered.

Depending on the disease severity, glaucoma patients need monitoring once in 3-12 months. Monitoring glaucoma is all about assessing progression. Progression analysis in glaucoma includes eye pressure and optic nerve evaluation.

Treatments modalities used alone or in combination include:-

Eye Drops
Certain prescription eye drops decrease intraocular pressure by reducing the amount of fluid your eye produces. Several different classes of glaucoma medications are available to provide pressure reduction including beta-blockers, prostaglandin analogues, alpha-adrenergic agonists, miotics, Rho kinase inhibitors, and oral and topical carbonic anhydrase inhibitors. These medications work by either reducing the rate at which fluid in the eye is produced or by increasing the outflow of fluid from the eye.

Oral Medications
Like eye drops, oral prescription medications help reduce pressure inside your eye.

Laser Therapy
Using a laser beam, your ophthalmologist opens clogged channels inside the eye, releasing fluid build-up. Laser therapy is an outpatient procedure.

Filtering Surgery
Filtering surgery to create a new passage for fluid drainage. Surgery is usually reserved for cases that cannot be controlled by medication and after appropriate laser treatment.

Implant Surgery
To enhance filtering surgery, your ophthalmologist may insert tiny drainage devices or “aqueous shunts” to keep the surgically created drainage opening from closing.

MIGS
Minimally invasive glaucoma surgery (MIGS) has been developed in recent years to lower eye pressure and prevent progression of glaucoma. MIGS procedures are indicated in certain types of glaucoma and work by using microscopic-sized equipment and tiny incisions.
In some cases, a single surgery is not enough to slow down the progress of glaucoma. Repeat surgery / surgeries and /or continued treatment with medicines may be necessary. Without treatment, glaucoma can cause permanent blindness.

Cataract Surgery
Cataract surgery can reduce the eye pressure temporarily in some patients, but this effect is usually not sustained in the long run. In patients with glaucoma or those suspected to have glaucoma, cataract surgery requires a special understanding that cataract surgery can lead to a rise in eye pressure insome patients. Patients who have undergone glaucoma surgery previously need special care while undergoing cataract surgery.