Glaucoma is an eye disease in which pressure inside the eye (intraocular pressure) rises dangerously high, damaging the optic nerve and causing vision loss. In a healthy eye, fluid is produced in the ciliary body, enters the eye, and then drains through tiny passages called the trabecular meshwork. In people with glaucoma, these passages become blocked and intraocular pressure rises.
Some cases of glaucoma can be treated with medications. For others, laser or traditional surgery is required to lower eye pressure. Common surgeries include:
- Laser Peripheral Iridotomy (LPI) – For patients with narrow-angle glaucoma. A small hole is made in the iris to increase the angle between the iris and cornea and encourage fluid drainage.
- Argon Laser Trabeculoplasty (ALT) and Selective Laser Trabeculoplasty (SLT) – For patients with primary open angle glaucoma (POAG). The trabecular passages are opened to increase fluid drainage. ALT is effective in about 75% of patients, and SLT may be repeated.
- Nd: YAG Laser Cyclophotocoagulation (YAG CP) – For patients with severe glaucoma damage who have not been helped with other surgeries. The ciliary body that produces intraocular fluid is destroyed.
- Filtering Microsurgery (Trabeculectomy) – For patients who have not been helped with laser surgery or medications. A new drainage passage is created by cutting a small hole in the sclera (the white part of the eye) and creating a collection pouch between the sclera and conjunctiva (the outer covering of the eye).
- Tube Shunt Surgery – May be recommended for patients with neovascular glaucoma, failed trabeculectomy, or susceptibility to developing scar tissue. A thin, flexible tube (a shunt) with a silicone pouch is inserted in the eye to facilitate drainage.
- Canaloplasty – the newest low-invasive filtering procedure. Delicate dilation and stretching of the drainage canals leads to decreased pressures without traditional “penetrating” techniques.
Dr. Maehara routinely performs the following advanced glaucoma surgeries in addition to standard trabeculectomy: Non-penetrating deep sclerectomy with Aquaflow implant, in-office SLT laser, Ahmed glaucoma drainage devices, and Canaloplasty.
All glaucoma patients are strictly monitored using:
Humphrey® Visual Field
The Humphrey Visual Field is a special automated procedure used to perform perimetry, a test that measures the entire area of peripheral vision that can be seen while the eye is focused on a central point. During this test, lights of varying intensities appear in different parts of the visual field while the patient’s eye is focused on a certain spot. The perception of these lights is charted and then compared to results of a healthy eye at the same age of the patient in order to determine if any damage has occurred.
This procedure is performed quickly and easily in about 15 minutes, and is effective in diagnosing and monitoring the progress of glaucoma. The Humphrey system uses advanced blue-yellow perimetry, also known as Short Wavelength Automated Perimetry (SWAP), which is proven to detect signs of glaucoma-related vision loss earlier than other tests.
Patients with glaucoma will often undergo this test on a regular basis in order to determine how quickly the disease is progressing. The Humphrey Visual Field test can also be used to detect conditions within the optic nerve of the eye, and certain neurological conditions as well.
Optical Coherence Tomography
Optical coherence tomography (OCT) is an advanced technology used to produce cross-sectional images of the retina, the light-sensitive lining on the back of the eye where light rays focus to produce vision. These images can help with the detection and treatment of serious eye condition such as macular holes, macular swelling and optic nerve damage.
OCT uses technology that is similar to CT scans of internal organs, using a scattering of light to rapidly scan the eye to create an accurate cross-section. Unlike other imaging techniques, OCT uses light to produce high resolution images, rather than sound or radiofrequency waves. Your doctor can evaluate and measure each layer of the retina through this image and compare it with normal, healthy images of the retina.
The OCT exam takes about 10 to 20 minutes to perform in your doctor’s office, and usually requires dilation of the pupils for the best results.