How does glaucoma affect the eye?
New medical and surgical treatments for glaucoma are being diligently researched in the United States. Multiple national clinical trials are ongoing, examining the efficacy of different existing surgical and medical treatment modalities for glaucoma, including the Ocular Hypertension Study (OHTS), the Advanced Glaucoma Intervention Study (AGIS), the Collaborative Normal Tension Glaucoma Study (CNTGS), the Collaborative Initial Glaucoma Treatment Study (CIGTS) and the Tube Versus Trabeculectomy Study (TVT).
New medical treatments for glaucoma that affect blood flow to the optic nerve head, intraocular pressure and survival of retinal ganglion cells are being investigated. Although decreasing intraocular pressure is the only current treatment demonstrated to delay progression of most forms of glaucoma, neuroprotection to promote survival of the retinal ganglion cells either by preventing cell death (apoptosis) directly using apoptosis inhibitors or improving the cellular environment in the eye, such as through blood flow regulation or addition of nerve cell growth factors are actively being tested.
Multiple technologies are being employed for the early detection or progression of glaucoma, including retinal nerve fiber and other structural analysis through scanning laser polarimetry, optical coherence tomography, scanning confocal microscopy, and ocular blood flow Doppler analysis. The hope is that use of these technologies will aid in the earlier detection or progression of glaucoma before other methods can. Several different major trials are underway to see if these technologies can indeed help to prevent vision loss from glaucoma. Different functional tests of retinal ganglion cell function including short wavelength automated perimetry (SWAP), frequency doubling time (FDT), and pattern electroretinogram (PERG) are also actively being studied for early detection of visual field loss.
These new types of functional tests for glaucoma are potentially much easier for patients. Pattern electroretinogram (PERG) for the eye can be thought of as being analogous to the electrocardiogram (EKG) for the heart. By studying the electrical activity pattern of the eye under different patterns of visual stimuli, scientists and clinicians at many centers throughout the world are designing new methods of diagnosing early glaucoma and for studying the progression of glaucoma that are inherently much easier for patients with glaucoma when they are being tested.
Laser surgical techniques such as selective laser trabeculoplasty (SLT) and non-penetrating types of filtering surgeries are being compared to conventional treatments such as argon laser trabeculoplasty, trabeculectomy and drainage implants. Newer glaucoma drainage implants that are currently in design and early clinical trials phases are possibly easier and safer to implant and provide better pressure control. Currently IEC is very involved in research of several of these alternative treatments.
One of the most interesting and potentially important areas of glaucoma research is in the area of genetics. Studies of families with glaucoma have identified several genes involved in glaucoma and the function of these genes and the search for more genetic information about the different forms of glaucoma are ongoing. It is hoped that eventually these studies will provide scientists with new targets to treat and possibly even cure some forms of glaucoma. They may also possibly allow for genetic screening for patients at risk of developing glaucoma, allowing for earlier preventative treatment.
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