PROCEDURE
Glaucoma
What is Glaucoma?
When a person suffers from glaucoma there is usually no pain and the patient will begin to lose their peripheral vision in such a slow manner that it is not noticed sometimes for many years.
Glaucoma is often called the “silent thief of sight” because most often the patient has no symptoms until permanent damage to the eye has occurred.
Generally speaking, glaucoma is basically an incurable but treatable condition.
Generally IOPs of 21 mm hg are considered the upper limit of normal. However, if patient has poor vascular circulation (low blood pressure, atrial fibrillation, hypertension, high cholesterol, partial blockage of carotid or ocular circulation00), or genetically acquired physiology that is more sensitive to IOP, then pressures may need to be maintained at much lower levels. In severe cases, IOPs in 10 to 12 mm hg may be the desired goal to preserve the eye function.
Healthy Eye
Etiologies other than genetic include blunt trauma to the eye damaging the filtering mechanism, inflammatory events or blood in the front of the eye that may partially block or damage the trabecular meshwork (filtering tissue in the eye). Some patients are genetically designed such that when they are using steroids whether in topical eye drops, creams, oral, or intravenously, the IOP may rise—sometimes dramatically and dangerously. If you have ever been suspect of this condition, IOPs should be checked whenever steroids are used.
Glaucoma Eye
Acute Angle Closure Glaucoma (AACG) is a special type of glaucoma where the eye is very small, the anterior chamber is very shallow and the intraocular lens is big. In this scenario, if the pupil dilates largely and gets pushed into the angle by the aqueous trying to drain out of the eye, the iris at the base my get pushed into the filtering angle and block all fluid escaping. This can cause a sudden, rapidly painful and potentially vision threatening event to occur. Immediate attention needs to be taken. Call the answering service immediately! This usually occurs early in the mornings.
Who are higher risk factor groups?
- Those with family history of glaucoma
- Patients with history of significant blunt trauma to eye or head
- African-Americans and Hispanics
- Patients with diabetes
- Patients with history of autoimmune conditions causing inflammatory iritis or uveitis
- Smokers
- Patients with hypertension
- Patients being treated with steroid medications—drops, creams, oral, intramuscular or intravenous
- Patients taking certain drugs for allergy, nervous conditions, digestive problems
How is Glaucoma detected?
Annual eye examinations which include IOP check is the best method of prevention, especially after age 40.
Thanks to new technology glaucoma can be detected quickly and painlessly usually without dilation using either a Heidelberg Retinal Tomograph (HRT) or Heidelberg Ocular Computerized Tomography (OCT) which measures down to one micron accuracy. These technologies generate very precise, comprehensive analysis and documentation for early detection and follow-up mapping of disease progression.
Your IOP is measured by a tonometer (the blue light on the slit lamp) or by a new hand held device.
Your optic nerve is inspected and viewed both directly and by new hand held lens systems.
Gonioscopy lens allows direct inspection and grading of the tissue in the filtering/drainage area of the eye.
Visual field testing documents your peripheral vision in each eye and is standardized such that it monitors the changes that occur in the visual field.
Treatment for Glaucoma-Chronic Open-Angle Glaucoma (COAG)
Laser Surgeries – There are two basic laser techniques. One is a painless thermal laser which we use combined with cataract surgery. The laser decreases the tissue involved in making the fluids inside the eye. The most common procedure is Selective Laser Trabeculectomy (SLT). This is a painless cold laser pulse a couple millionths of a second duration that causes the cells in the filter area to die slowly enough that the body replaces the lasered cells with new young normal filtering cells. At Cross Eye Centers we were one of original developers of new, more successful treatment techniques with this laser. Success rate is about 94% and generally lasts 5 to 7 years before surgery is repeated. Patients are able to drive themselves home after treatment. Generally the IOP does not decrease immediately because new cells are being grown and maturing. Hence, most patients finish their current bottle of medications, stay off medications for a week, and then have an IOP check in the office.
Prescription Medicines may be combinations of one or more topical drops and or oral medications which either decrease the production of intraocular fluids and/or increase drainage of the fluids out of the eye. If these medications are too expensive, generics are often available. Several of the pharmaceutical companies have programs to provide medications to patients in financial need. Ask staff and check drug websites.
Trabeculectomy is a drainage “filter hole” performed at a surgery center that allows fluid inside the eye to escape into the space at the top of the eye under the conjunctiva and be adsorbed. This is usually performed when medications and laser treatments are not successful.
Glaucoma Shunt – This is a small tube device which is passed through a drainage hole out of the anterior chamber. The tube keeps the drain open, and drains the aqueous into the space under the conjunctiva. There are several different designs and sizes. These are the most complicated and are usually done after other attempts fail.
Treatment for Acute Angle Closure Glaucoma (AACG)
Laser Peripheral Iridectomy is a procedure performed when a patient presents in the office with very shallow anterior chamber, histories suggesting episodes of intermittent acute angle closure glaucoma (AACG), or patients presenting with acute eye pain, blurred vision, very high IOPs, and very shallow or closed anterior chamber angles. In this type of glaucoma the intraocular lens is thick enough and the pupil has opened wide enough to block the aqueous from getting into the filtering angle and draining. This usually begins at night when the pupil dilates or when the patient has episode of excitement.
There is a surgical procedure, Peripheral Iridectomy that can be done in an operating room as a primary treatment or as an additional procedure to patients undergoing some other intraocular procedures.