Glaucoma, often referred to as “the sneak thief of sight”, is a progressive disease that causes damage to the optic nerve. Increased intraocular pressure in the eye results in loss of nerve fiber layers that transmit information from the eye to the brain. The term “increased” is relative to each individual patient, meaning certain patients can safely maintain an intraocular pressure of 20 without any damage while others experience vision loss with a pressure reading of 12. High pressure in the eye is caused by blocking of the drainage canal that lets fluid from inside of your eye flow out resulting in a build up of intraocular fluids. High pressure can also be caused by a narrow angle, in which the eyes anatomy leaves no room for the fluid to drain out also resulting in a build up intraocular fluids.
As glaucoma damages the optic nerve, peripheral vision is lost at a slow speed without the patient’s knowledge of any problem.
Most people with early stage glaucoma have no symptoms, pain or noticeable loss of vision from increased eye pressure. Because it is not detectable by patients in the early stages, it is important to have a regular eye exam by your doctor for diagnosis and treatment before long-term, irreversible vision loss occurs. People over 40 with a family history of glaucoma should be monitored by an ophthalmologist yearly for early detection.
Your doctor may feel you are suspicious of glaucoma but are not a candidate for treatment yet and recommend you be followed at shorter (6-12 month) intervals to monitor the condition as it progresses. If treatment is initiated, the patient has a choice between glaucoma drops instilled in the eye daily to lower the eye pressure or laser surgery for glaucoma to help the fluid drain from the eye thereby lowering the eye pressure. In some cases, your doctor may elect to do surgical intervention once other methods have been tested and failed.
Your Visual Acuity will be assessed using the Snellen eye chart which measures how well each eye can see. During an examination, our doctors will evaluate your intraocularpressure (IOP) by Tonometry. A high eye pressure reading is often one of the first indicators of glaucoma. The thickness of the cornea is measured by pachymetry, because corneal thickness affects eye pressure readings. At the Slit Lamp Microscope, the doctor will inspect the drainage angle during a procedure called Gonioscopy. An Optic Nerve Exam, performed when the pupils are dilated, is necessary to detect optic nerve damage.
Additional Tests may be ordered that allow unique views and analysis of the state of your optic nerve, comparing the way the optic nerve appears during the test to a database of other individuals categorized by age, gender, race, and level of glaucomatous damage.
A Humphrey Visual Field (HVF) or Frequency Doubling Technology (which detects damage faster and earlier in the disease process) analysis of your current amount of peripheral field loss will be ordered. The Ocular Coherence Tomographer, (OCT) scans through your dilated pupil to assess the quantity and quality of the optic nerve fibers themselves. The Heidelberg Retinal Tomographer (HRT) scans the appearance of the optic nerve, including changes in its shape and appearance over time. In Glaucoma, the elevated eye pressure permanently damages these fibers. Tracking the amount of nerve fiber loss helps your doctor in determining when and if to intervene with additional glaucoma treatment. Digital Optic Nerve Photographs or 3–Dimensional Optic Nerve Photographs will be taken to aid in the further evaluation of your optic nerve’s appearance over time. Blood flow to the microscopic cells of the optic nerve is an important factor in optic nerve health, and may be assessed through Ocular Blood Flow Analysis and 24-hour Blood Pressure Monitoring (similar to wearing a Holter monitor).
Three scans are taken of the optic disc and nerve fiber layer. These are combined to create a high quality, 3-D topography. Our research at the Eye Research Foundation set the standard protocol for how to measure ocular blood flow.
EFEI has the FDT which can detect visual field loss in perimetrically normal eyes with open-angle glaucoma. Recently, research has indicated that a technology known as FDT is very useful in detecting visual field loss secondary to glaucoma. Additionally, this same technology has also been shown to predict the visual field loss pattern that would be seen on standard testing.
At East Florida Eye Institute, we make use of this technology daily, and feel we enhance service to our patients with the addition of this technology. On a regular basis, we are able to give our patients thorough, consistent and useful information regarding the status of their eye health; including, but not limited to glaucoma. With the addition of the FDT technology to the practice, we have been able to increase quality and exceed patient’s expectations.
•Scientists at Harvard have shown that until about the age of two, the neurons in the human brain are still growing
•They have found a molecule (SOCS3) that appears to put the brakes on neuron growth in adult mice.
•They also found that damaged neurons sprout after blocking this molecule in adult mice with crushed optic nerves
•This work is an important advance towards understanding why axons of adult nerve cells don’t regenerate.
•In future the ideal treatment will probably involve delivering drugs to an injured area of the brain or spinal cord so that the nerve tissue re-grows especially in conditions like Alzheimer’s disease and Glaucoma.
Treatment for glaucoma depends on the specific type of glaucoma, its severity and how the eye responds to treatment. The main goal is to lower the eye pressure to a level that stabilizes the disease to prevent further damage/vision loss. The level of “safe” eye pressure is different for each individual. Unfortunately, glaucoma treatment does not reverse damage to the optic nerve.
Lowering eye pressure is accomplished in one of two ways: by decreasing aqueous fluid production (inflow), or increasing aqueous fluid drainage (outflow). Methods of eye pressure reduction include: medications, glaucoma laser surgery and glaucoma surgery.
Medications in the form of eye drops or pills, or a combination of the two can increase outflow, decrease inflow or a combination of the two. The prescription drugs can be eye drops or pills. Some patients cannot tolerate these medications, and some side effects may outweigh the benefits of the treatments. We helped develop a new treatment, Durysta, which is an implant that slowly releases medication in the eye.
Laser trabeculoplasty stimulates the trabecular meshwork (drainage angle) to function more efficiently. This is an in-office procedure. It is relatively safe with few side effects. We offer two different types of laser trabeculoplasty: Argon Laser Trabeculoplasty (ALT) and Selective Laser Trabeculoplasty (SLT).
SLT and ALT lower the intra ocular pressure (IOP) by ~20%. They are about 80% effective in the first year. However the efficacy may wear off over time: @ 5 years – 50% effective and @ 10 years – 33% effective.
These lasers may not need to be repeated at the frequency that many ophthalmologists are performing them. In a study by Dr. Frenkel, treating 1/3 of the eye is just as effective as treating 1/2 of the eye. While SLT can be repeated over the same area of the eye, ALT cannot.
In laser iridotomy, a small hole is created in the iris to improve outflow of aqueous humor into the drainage angle. This procedure is done for narrow or closed angles.
A laser iridioplasty removes a portion of the iris near the root to alter the shape of the pupil therefore drainage angle, improving outflow of aqueous humor.
Glaucoma surgery is called for when eye medications and laser surgery are insufficient to control glaucoma progression. In Trabeculectomy, a new drainage channel is created in the eye. In Aqueous shunt or Seton procedures, a small plastic tube drains fluid from the front of eye to lower eye pressure and is usually reserved for eyes at high risk for failure with trabeculectomy.
The goal of glaucoma surgery is to reduce damage to the optic nerve by lowering the pressure inside the eye. Micro-Invasive Glaucoma Surgery, or MIGS, achieves this using microscopic instruments to make very small incisions in the eye. We use VISCO 360. iStent & MicroPulse at EFEI.