Glaucoma Symptoms, Testing, and Treatment
Glaucoma is a common disease which can cause a progressive loss of vision if left untreated. The good news is that with modern day advances in technology, we now have excellent methods of diagnosing glaucoma and effective therapies for treatment of this disease.
What is glaucoma?
Glaucoma affects the optic nerve of the eye which sends signals from the eye to the brain where they are processed to form images. In patients with glaucoma, there is a slow, progressive loss of the nerve fibers which make up the optic nerve. You cannot see your optic nerve but your Ophthalmologist is able to see it when examining you at the slit lamp, a special microscope for eye examination. He or she may use special lenses or devises to visualize our optic nerve.
If you are diagnosed with glaucoma, there are several treatments available.
- Prescription eye drops
- Oral medications
- Selective Laser Trabeculoplasty (SLT)
If you have any concerns or questions regarding glaucoma or would like more information on glaucoma, please contact our office to set up an evaluation.
Glaucoma Risks & Types
Depending on your general health, eye health, and family history, a number of factors may increase your likelihood of developing glaucoma. An increased risk of glaucoma occurs when you:
- Have higher than normal intraocular pressure (IOP)
- Are above 40 and especially above 60 years of age
- Are of African-American descent or Hispanic and above 60 years of age
- Are extremely nearsighted
- Have high blood pressure or diabetes
- Have a family history of glaucoma
Prolonged use of oral contraceptive birth control pills, as well as the early onset of menopause, may increase glaucoma risk in women, and anyone suffering from sleep apnea needs to be carefully examined as this condition significantly increases glaucoma risk.
If you have had trauma to your eyes such as from a sports injury or car accident, or if you have been treated for asthma or other conditions for long periods of time with steroid inhalers, or have a corneal thickness less than 0.5mm, you too might be at greater risk of developing glaucoma.
The two main types of glaucoma are Primary Open Angle Glaucoma (POAG), and Angle Closure Glaucoma.
Patients with Primary Open Angle Glaucoma usually have an increase in Intraocular Pressure (IOP) upon routine measurement, called Tonometry. Acute Angle Closure Glaucoma is one of the only types of glaucoma that causes obvious symptoms that may include pain, light sensitivity, redness, blurred vision, colored haloes around lights and nausea or vomiting and is a medical emergency.
If these symptoms occur please call one of our locations for an immediate appointment.
The Science of Glaucoma and the Types of Glaucoma
Aqueous fluid & intraocular pressure (IOP)
Aqueous fluid is a clear and watery ultra-filtrate of blood that fills the anterior and posterior chambers of the eye. Flowing more at night than in the day, it is a source of nourishment for the eyes and plays a part in waste removal. The eye forms and reabsorbs aqueous fluid continuously. The regulation of intraocular pressure (IOP) is in part a result of the flow of aqueous fluid. IOP can be determined by comparing the inflow versus the outflow of aqueous fluid in the anterior segment (the chamber on the front of the eye covered by the cornea) IOP remains constant if the outflow is equal to the inflow. If outflow is less than inflow, the IOP rises.
Most people with glaucoma suffer from one of two major types of the disease: “open angle” and”closed angle” glaucoma.
HEPS provides glaucoma treatment for both disease types in all of our office locations.
What is the angle?
To better understand these two types of glaucoma we first have to explore why the term”angle” is used to describe them.
The anterior chamber is the fluid-filled space inside the eye between the iris and the cornea’s innermost surface, the endothelium. Aqueous fluid fills the anterior chamber. In differentiating between open angle and closed angle glaucoma experts use the iris, the corneal endothelium, and the trabecular meshwork as points of reference.
The anterior chamber angle is often referred to as “the angle.” The base of the angle is the iris. The apex of the angle is the trabecular meshwork. The top of the angle is the corneal endothelium. If a miniature protractor could be placed on the base of the angle (the iris) to determine the width of the anterior chamber angle in degrees, a 45 degree angle would be considered wide (or “open”), and a ten degree angle would be considered narrowed (or “closed”).
Open angle glaucoma
Chronic open angle glaucoma progresses at a slower rate and is often not noticed until there is a significant loss of vision. On the part of doctors, being vigilant and asking patients questions can uncover underlying risk factors. Eye pressure being above normal levels is not the reason all people have open angle glaucoma, however decreasing eye pressure has been proven to forestall the progression of glaucoma even in the cases where elevated pressure does not occur. Peripheral vision tends to be affected first, and if not treated, open angle glaucoma will lead to a total loss of entire vision.
Closed angle glaucoma
Closed angle glaucoma is often painful and sudden, characterized by visual loss that progresses quickly and discomfort that often leads people to seek medical attention before permanent damage occurs.
Closed angle glaucoma is diagnosed when aqueous fluid cannot reach the anterior chamber angle. It accumulates and forces the iris to obstruct the trabecular meshwork. Contact between the iris and the trabecular meshwork may ultimately damage the function of the meshwork so that it fails to respond to aqueous fluid production leading to an increase of IOP (intraocular pressure). Scars called synechiae form, causing an irreversible block in aqueous outflow.
Most cases of closed angle glaucoma do not reveal themselves through symptoms. In the cases where symptoms do occur patients experience eye pain and redness, blurred vision, headaches, vomiting, and the appearance of halos. In addition to these symptoms doctors look for mid-dilated pupils, lack of response to light, cloudy corneas and reduced vision to diagnose closed angle glaucoma.
Less common and less treatable types of glaucoma
Forms of developmental glaucoma include; congenital, infantile and hereditary/familial disease. Forms of secondary glaucoma include; inflammatory, phacogenic, intraocular hemmorhage, traumatic glaucoma, neovascular glaucoma, drug-induced glaucoma, and glaucoma of miscellaneous origin. Both developmental and secondary glaucoma groups respond to treatment but resulting outcomes vary.
Individuals with poor blood flow are at high risk for neovascular glaucoma which is rare, untreatable, and characterized by the development of abnormal vessels that block fluid drainage in the eye. Toxic glaucoma which is also untreatable results from an unexplainable rise in intraocular pressure.
Absolute glaucoma or end-stage glaucoma
Absolute glaucoma is the final stage of glaucoma. This stage is marked by total loss of vision, pain, and a stone-like appearance of the eye. Treatment is focused on reducing pain and keeping the eye comfortable.
Glaucoma Testing & Diagnosis
During your examination, we may perform a number of tests in order to make the most accurate diagnosis of glaucoma. These include:
- Tonometry to measure eye pressure
- Ophthalmoscopy to carefully examine the inside of the eye-especially the optic nerve
- Visual Field testing using computer bowl-like instrument to evaluate your “side” or peripheral vision to see how sensitive your side vision is in various directions
- Gonioscopy to directly observe the health and condition of the angle of your eye where the Iris meets the cornea
- OCT or “optical coherence tomography” digital imaging of the optic nerve
- Retina and Pachymetry or corneal thickness measurement as corneal thickness can alter the accuracy of the measurement of intraocular pressure (IOP) and it appears that patients with thin corneas may be inherently more likely to develop glaucoma