What is the Best Eye Drops for Glaucoma?
Medications, laser treatments and surgery are effective methods for reducing intraocular pressure and preserving eyesight, but not all treatments work equally well for everyone. You and your doctor should opt for a treatment plan that takes into account your type of glaucoma, the severity, how fast it is progressing and other factors.
If there is only damage to the optic nerves or loss of mild vision, a reasonable goal for initial therapy could be to reduce the intraocular pressure by 20 to 25 percent below the average of several baseline measurements. If the damage is more advanced, your doctor may set another goal.
Most doctors will initially tell you about a medical treatment plan (instead of laser treatment or surgery) to lower intraocular pressure, unless glaucoma medications are not a viable option for you.
In addition, when defining treatment, your doctor must inform you in detail about the potential benefits and risks, including possible side effects. Treatment decisions must take into account both your comfort (including how well you tolerate a medication or treatment, its side effects, risks and healing time required) and its effectiveness in reducing intraocular pressure. If your treatment involves taking medications, it is important to take them regularly and appropriately, as prescribed, or it may not work.
Treatment of Glaucoma with Medications
The eye, like the brain, protects itself by means of a barrier against potentially harmful substances. This hemato-ocular barrier makes it difficult for the pills or injections go into the bloodstream. As a result, most medications for glaucoma are topical, which means that they are applied on the surface of the eye, using eye drops or ointments, which are absorbed into the eye's own circulation.
What is the Best Eye Drops for Glaucoma?
Prescription drugs tend to be divided into "classes", depending on how they work. Most of these medications are available only in drops, except where indicated.
Analogs of Prostaglandins: They function as vasodilators, which mean that they expand the blood vessels in the eye. This helps the aqueous humor to leave the eye, through the uveoscleral pathway. From there, it is eliminated through the lymphatic system. This class of medications can reduce intraocular pressure from 18 to 31 percent on average, with effects relatively minor side effects, such as sensitivity and irritation of the eyes, and also side effects similar to those of flu, which appear and disappear. Sometimes, these drugs can cause a darkening or change in eye color.
Beta-blockers: These modify the response of their nervous system, "occupying" the receptors, which would otherwise trigger a response.
In glaucoma, they cause the body to produce and secrete less aqueous humor, which leads to an average intraocular pressure reduction between 20 and 27 percent. However, in addition to affecting the eye, there may be side effects that affect the heart, lungs and other organs.
Alpha (A2) Adrenergic Agonists: They reduce the production of aqueous humor and increase its secretion through the uveoscleral pathway, achieving an approximate reduction between 13 and 29 percent of intraocular pressure.
The Carbonic Anhydrase Inhibitors: These reduce the volume of aqueous humor, by partial inhibition of the enzymes responsible for their production. This can reduce your intraocular pressure between about 15 and 20 percent. They can also improve blood flow to the retina and optic nerve.
The Miotics: Also called cholinergic agents, they cause the tissues of the eye to contract, which opens the drainage pathways and increases secretion, thus reducing the intraocular pressure between 15 and 25 percent.
Hyperosmotic Agents: They rapidly reduce intraocular pressure by decreasing volume vitreous, or the gelatinous fluid that fills the cavity behind the lens of the eye.
Till the date the group of beta-blockers are considered first-line drugs of choice, for its excellent efficacy in reducing intraocular pressure, long duration of action and few adverse ocular effects, although some authors consider the prostaglandin analogs of first choice. The place of beta-blockers as initial monotherapy is under debate.