Glaucoma

Glaucoma is a disease that causes irreversible damage to the eye’s optical nerve. The optical nerve connects with the retina and transmits signals to the brain, which are later interpreted as images.

Different risk factors can cause glaucoma, among them, the increase in intraocular pressure. Intraocular pressure is generally the result of problems in the drainage of the aqueous humor. The increased pressure leads to the alteration of the nervous fibers that comprise the optical nerve, which results in the development of glaucoma.

Nearly half of patients suffering from glaucoma are unaware of it. The disease usually presents no symptoms at the beginning and its proper and early treatment may help preserve vision.

Open-angle glaucoma
It occurs when the trabecular meshwork becomes less efficient in draining the fluid (aqueous humor). Pressure in the eye starts to increase and over time this may damage the optical nerve. Damage to the optical nerve can also happen with different ocular pressures in different persons. The physician will establish the ideal pressure for your eye. On the other hand, it is not only important to measure the eye pressure and essentially evaluate the vision, but also to examine the optical nerve to achieve a proper diagnosis, and once the diagnosis is done, conduct proper controls.

Normal-tension glaucoma
Pressure is considered ‘normal’ when it is 21 mmHg or lower. But some eyes with low ocular pressure suffer anyway from damage to the optical nerve and loss of the visual field (appearance of spots or black zones in vision). Likewise, in ocular hypertension the eye pressure is greater than 21 mmHg, but there is no damage to the optical nerve or the visual field. They are suspicious for glaucoma and should be closely monitored.

Narrow or ‘closed’-angle glaucoma
It happens when the ocular structures responsible for draining the intraocular fluid are too narrow and the iris (which colors the eyes) blocks the drainage meshwork. Should this drainage angle get completely blocked, ocular pressure would increase suddenly causing an ACUTE ATTACK or ACUTE CRISIS of glaucoma or ocular pressure. Symptoms include severe ocular pain irradiating to the forehead and the head, very red eye, blurry vision, vision impairment, halo vision or rainbow viewing around lights, headache, nausea and vomiting. An acute glaucoma attack is a MEDICAL EMERGENCY and must be treated urgently.

Secondary glaucoma
It occurs secondary to another eye pathology such as trauma, corticoid treatment, tumors, crystalline exfoliation syndrome, pigment syndrome, etc.

Congenital glaucoma
It is very rare and appears between birth and the age of 3; it is owed to a birth defect in the eye angle caused by a faulty development, which prevents the drainage of the aqueous humor. Parents begin to notice that the child has great sensitivity to light (photophobia), watery eyes and close their eyes frequently. As the disease unfolds, the eyes turn more dull and greater than normal.

• Age
• History of migraine, diabetes and low blood pressure
• African or Hispanic ethnicity
• Asian people have a higher risk of suffering from closed-angle glaucoma
• Hyperopia (far-sightedness), have a higher risk of suffering from closed angle
• Myopia (short-sightedness)
• Thin central cornea
• High ocular pressure
• Not attending ophthalmology medical checks

• Computerized visual field: functional test.
• Pachymetry: measures the thickness of the corneal center.
• Optical Coherence Tomography (OCT) of layers of fibers and ganglion cells: structural test.
• Retinography: optical nerve color.

Treatment of glaucoma will depend on the specific type and severity of glaucoma.

Drops
We have several drops available. It is of utmost importance that you tell the physician if you are taking any medication for another general pathology, such as diabetes, heart conditions, blood conditions, aspirins, psychiatric medication, etc., in order to choose the proper medication for you. Drops should be applied at all times, EVERY DAY, as indicated. Never interrupt the treatment and if any problem arises go immediately to the clinic to ask for assistance.

Peripheral iridotomy with Yag Laser
It is the treatment of choice for acute glaucoma and as preventive medicine for acute glaucoma in predisposed patients (narrow angles). It consists in making a small hole in the most peripheral part of the iris, either in the upper or the temporal zone, to facilitate drainage of the aqueous humor. It is performed using anesthetic drops and a special magnifying glass. After the procedure, anti-inflammatory and anti-glaucomatous drops are indicated for a couple of days. Sometimes it must be performed in more than one session to achieve a proper size.

Peripheral iridoplasty with Argon Laser
The purpose is to generate round scars in the most peripheral part of the whole iris in order to move the iris backwards and make greater space in the front portion of the eye. It is usually indicated in Plateau Iris Syndrome and may sometimes be used in closed-angle glaucoma. It is also performed using anesthetic drops and a special magnifying glass.

Trabeculectomy
A conventional glaucoma surgery, it is performed where prior treatments were not able to lower the ocular pressure or where the disease seems to advance. It may also be conducted on people who cannot afford the cost of the drop treatment or who are unable to place the drops themselves. It consists in making a fistula between the eye and the subconjunctival space (above the white portion of the eye) in an attempt to form a blister. This is the most common surgical treatment in patients with glaucoma, but its role is ever evolving. Research has demonstrated that patients with more advanced glaucoma right from the start show more slowly progression of visual field deterioration where surgery is the first choice before using drops; but this decision should be made on case-by-case basis. It can be performed with either topical or parabulbar anesthesia. It is an outpatient surgery and patients usually leave the operating room wearing a compressive patch on the operated eye. Special substances (antimetabolites) are often used during the surgery to reduce postoperative scarring. In addition, postoperative care is very important: many times, stitches must be trimmed and antimetabolite injections must be given on the eye wall to keep the long-term functionality of the filtering blister.

Ahmed valve
Traditionally used in cases where conventional surgery did not work, in complex glaucoma such as inflammatory, neo-vascular or traumatic glaucoma. Since a study was published comparing both surgeries as initial surgery, many choose to place these valves as a first choice for glaucoma surgery. The valve has a silicone tube connected to an episcleral plate or explant, made in different sizes and from different materials as per the model and brand. Materials are biocompatible, but a thick fibrovascular capsule (Tenon’s cyst) may form around it. It is performed with parabulbar anesthesia. The quadrant mostly used is the superior temporal one, but additional valves may be placed, where necessary, in other quadrants. This type of valves may undergo a hypertension period between week 4 and 16 after surgery, as the capsule is formed. It is important to monitor this phase in order to add treatment with hypotension drops if required.

Schlemm’s canal surgery
It consists of canaloplasty, the use of Trabectome and the placement of iStent, recently approved for use in our country but largely used around the world. They are indicated for very specific glaucoma cases. The physician will explain the best option for you.

Selective Laser Trabeculoplasty (SLT)
A safe method to treat eye hypertension in patients with open angle. It acts at the trabecular meshwork level increasing permeability and drainage of the aqueous humor and reducing intraocular pressure.

Transscleral Laser Cyclophotocoagulation (Cyclo G6)
This laser acts on the cells of the ciliary body causing the production of aqueous humor to go down. The procedure is performed in the operating room with local anesthesia (peribulbar).

Peripheral Iridotomy with Yag Laser
Peripheral Iridoplasty with Argon Laser
Drainage devices Ahmed valve