Not long ago, the only way to correct refractive errors was wearing prescription glasses and contact lenses. Today, however, different surgical techniques have been invented which change the shape of the cornea to correct refractive errors. A common technique is treatment by laser in which the patient's quality of vision is enhanced.

What Are the Causes of Glaucoma?

In some cases, the cause of glaucoma is detectable, such as eye injury, some eye surgeries, and the closure of the angle of the eye. However, in most cases glaucoma is a disease with unknown causes and many genetic and environmental factors are involved in its development.

Types of Glaucoma
Glaucoma can be divided into two groups, open angle glaucoma and closed angle glaucoma. It is good to know that the part of the eye between the iris (the colored part of the eye) and the cornea (the transparent part) is called the angle of the eye. Typically, a clear fluid circulates in the front part of the eye. It is produced in the eye and flows out from the angle of the eye. If this angle is blocked or damaged, the fluid would not be able to flow out of the eye which results in an increased intraocular pressure and causes glaucoma.

In most cases, patients develop open angle glaucoma. However, a significant percent of patients also suffer from angle-closure.

Symptoms of Glaucoma

Symptoms vary depending on the type of glaucoma:

    Congenital glaucoma (infantile glaucoma): It appears with symptoms such as cloudy cornea, tearing, light sensitivity and the enlargement of the eye.
    Open-angle glaucoma: In most cases of chronic open-angle glaucoma (and also angle-closure glaucoma), patients are not aware of glaucoma, until it advances and leads to visual field defects.

Angle-closure glaucoma: This condition is featured by acute symptoms such as decreased vision, tearing, photo phobia, seeing halos and rainbows around lights, nausea and vomiting. In such circumstances, the patient should be emergent referred to ophthalmologists and undergo treatment immediately.

Glaucoma Diagnosis
In most cases, comprehensive clinical exams, including the measurement of EYE pressure, examination of the angle of the eye, checking the appearance of the optic nerve, and visual field tests are enough to diagnose glaucoma. However, in some cases, other tests such as retinal and optic disc photography are also required.

Glaucoma Treatment

During the progression of glaucoma, the optic nerve gradually deteriorates and nerve cells die slowly. In case of being diagnosed with glaucoma, there is no cure for the loss of optic nerve fibers at present. The main goal of glaucoma treatment is to prevent the progression of the disease and to preserve the remaining vision so that the patient can do his/her routine activities.

Glaucoma is treated using a step wise approach. It begins with medications and if not successful, laser therapy is performed to reduce intraocular pressure. In the acute cases, when laser therapy doesn’t work either, glaucoma surgery will be performed.
 
Medications

The most common type of initial glaucoma treatment is medication. Glaucoma medicines are prescription eye drops and pills. These medicines reduce the  EYE pressure in two ways. Some of them reduce aqueous humor production, and some increase its outflow from the eye.

Glaucoma Surgery for Reducing Intraocular Pressure
Trabeculectomy: It’s the most common non-laser surgical procedure which is performed to control the eye pressure if using eye drops, pills and trabeculoplasty is not successful.

Trabeculectomy creates a controlled drainage canal for aqueous humor to flow to the space under the conjunctiva. A blister-shaped flap is made at the border of the cornea and the sclera after the operation, in which the canal through which the fluid of the eye outflows into the space under conjunctiva will be created.

Non-penetrating Glaucoma Surgery and Viscocanalostomy: Both of these procedures are less invasive than filtration surgeries during which the posterior chamber will remain intact. In these two surgical procedures, a deep flap is created in the sclera (the outer white layer of the eye), and another one between the superficial and deeper parts of the sclera which acts as a reservoir for vitreous body. During viscocanalostomy, the surgeon injects a gel-like substance into the Schema’s canal to dilate it.

Trabeculotomy: This method is somehow similar to trabeculectomy, in which a piece of the tissue in the eye’s drainage angle is removed to create an opening to enhance the outflow of fluid. Trabeculotomy is usually used to treat congenital glaucoma when the cornea is cloudy. This procedure, as well as goniotomy, is proper for treating children because they are both less invasive.

Goniotomy: In this surgical technique the doctor uses a special lens called goniolens to have a view of the angle of the eye. This method is used to treat congenital glaucoma when the cornea is not cloudy. During this treatment process, a hole is created in the Eye meshwork (a set of fine tubes located in the drainage angle of the eye) which ultimately enhances the drainage of aqueous humor.

Implanting Shunts: Aqueous shunts are small plastic canals or tubes on one side connected to a reservoir which is a rounded or oval plate. The shunt acts as an artificial drainage system and is placed in the eye through a small incision. The shunt accumulates the aqueous humor in a place under the conjunctiva (a fine layer covering the inner part of the eyelids and white part of the eye). The aqueous humor is finally absorbed by the blood vessels.

Our ophthalmologists in Tehran Noor Eye Hospital in Iran will provide you with additional information on this treatment.

General Preoperative Recommendations
1. The night before the surgery, take a bath and wash your face with diluted baby shampoo or soap.
2. Observe nutritional considerations according to the time of surgery given to the patient by the team.
3. If you are taking any specific medicine, be sure to inform your ophthalmologist and anesthesiologist.

Notes:

    Anti-hypertensive and Lipid-lowering drugs should be taken based on previous instructions.
    Heart medications should be taken based on previous instructions. In case of taking aspirin and wayfaring, taking them should be stopped if possible. However, be sure to consult with your doctor in this regard.
    Inform your ophthalmologist in case of having diabetes.

4. Be ready for pre-operative examinations including blood tests and cardiovascular consultation.

General Post-operative Care
1. After being discharged, your eye will be dressed and covered by a plastic shield. Avoid taking off the dressing at home.

2. Plan to rest on the first day after the surgery. After glaucoma surgery, avoid lifting heavy objects (typically heavier than 2kg). If you have to climb the stairs, caution is advised as well as having a family member as companion by your side.

3. While resting, keep your head more elevated than usual.

4. Having light foods, hot liquids, vegetables and fruits is good to facilitate recovery.

5. After glaucoma surgeries, experiencing foreign body sensation is normal. Painkillers are prescribed to reduce the patient's discomfort.

Notes

    The patient should undergo a follow-up visit one day after the surgery.
    Glaucoma surgery will help preserve vision and prevent blindness. It does not improve vision.