Laser Eye Surgery & Diseases
Reviewed by Brad Spagnolo, M.D.
Over the past thirty years Laser Eye Surgery has undergone unprecedented technological change, evolution and in many cases, revolution. This has allowed the development of treatment options for common vision problems, such as nearsightedness, farsightedness and astigmatism, and complex eye diseases such as diabetic retinopathy and glaucoma, that were simply not possible using conventional ophthalmic surgery. These Laser Eye Surgery developments have not only brought new treatment options, but in most cases have brought better outcomes in terms of patient quality of life through preservation and enhancement of vision.
With over one million LASIK procedures being performed each year, LASIK is the most frequently performed Laser Eye Surgery in the United States today. In general, when one thinks of Laser Eye Surgery, they first think of LASIK. Although www.seewithlasik.com concentrates on providing information and education about LASIK and its related laser eye surgery procedures for the correction of the common vision disorders mentioned above, it would not be complete without at least an overview of Laser Eye Surgery procedures for diseases such as diabetic retinopathy, age related macular degeneration, glaucoma and as an adjunct to modern cataract surgery.
Laser Eye Surgery for Diabetic Retinopathy
Diabetic Retinopathy is a sight threatening complication of systemic diabetes mellitus. Background Diabetic Retinopathy (BDR) may occur at any point in time after the onset of diabetes. In general, this is the first "stage" of diabetic retinopathy and, therefore, the least concerning. Early on, this condition is often present without any visual symptoms but is characterized by the retina displaying dot and blotch hemorrhages, microaneurysms and exudates or leakage from the fine blood vessels.
During this stage which may also be called Non Proliferative Diabetic Retinopathy (NPDR), it may lead to the formation of macular edema, or retinal swelling. Sometimes this condition will result in decreased and or distorted central vision. If there is clinically significant macular edema or swelling of the macula as a result of the leaky capillaries and microaneurysms in the retina laser eye surgery may be indicated in order to restore and preserve vision. Ophthalmologists apply very rigid criteria in order to determine who should have the laser eye surgery procedure called, Focal Laser Photocoagulation . These strict guidelines have been developed after many years of clinical trials and protocols in the Early Treatment Diabetic Retinopathy Study (ETDRS) in conjunction with the National Institutes of Health.
In its later stages, called Proliferative Diabetic Retinopathy (PDR), laser eye surgery become an even more important option. Proliferative Diabetic Retinopathy (PDR) carries a significant risk of visual loss. PDR is characterized by the development of new blood vessel growth or "neovascularization". Unfortunately, the neovascular vessels are fragile and have a tendency to break and bleed into the vitreous body in the back of the eye. In addition to sudden vision loss, this may lead to more permanent complications, such as retinal detachment and neovascular glaucoma. Thus, the elimination of neovascularization with laser eye surgery is an important treatment option.
Patients with proliferative diabetic retinopathy are often treated with the laser eye surgery procedure called scatter laser photocoagulation of the peripheral retina. The sooner the treatment is applied, the better. This laser eye surgery technique is also called Pan Retinal Laser Photocoagulation or PRP. By using the laser to stop and hopefully reverse the formation of the neovascularization Ophthalmologists are able to lessen the chance of significant vision loss. As with most types of laser eye surgery, Pan Retinal Photocoagulation is performed as an in-office or out-patient procedure. The actual laser eye surgery treatment usually 30-45 minutes per session. To be most effective Pan Retinal Photocoagulation often requires 3-4 individual treatment sessions. Thus laser eye surgery options for treatment of diabetic retinopathy include focal laser photocoagulation for macular edema and pan retinal photocoagulation for neovascularization.
Laser Eye Surgery for Age Related Macular Degeneration
Age Related Macular Degeneration (AMD) occurs in two primary types. Dry AMD that accounts for approximately 90% of cases and is generally the milder form of the disorder and is not amenable to treatment with any form of currently FDA approved treatment. Wet AMD, the second type is by far much more sight threatening but fortunately only accounts for approximately 10% of cases. Wet Age Related Macular Degeneration is treatable with certain types of laser eye surgery if it is diagnosed early enough.
Wet Age Related Macular Degeneration can sometimes be treated with one of two types of laser eye surgery. Traditional AMD laser eye surgery called Focal Laser Photocoagulation can use either the Argon Laser of the Diode Laser to thermally destroy blood vessels. The FDA recently approved a more advanced laser eye surgery technique called Photodynamic Therapy.
With Photodynamic Therapy a unique light activated dye called Visudyne is injected into your arm so that it circulates and fills the neovascularization beneath the retina. An Ophthalmologist then applies a non-thermal red laser which activates the Visudyne molecules so that they seal and reduce the unhealthy blood vessels.
In order to be a candidate for either Focal Laser Photocoagulation or Photodynamic Therapy you must first have a specialized diagnostic test called a fluorescein angiogram or indocyanine angiogram in order to determine whether there is the presence of subretinal neovascularization that is also called a choroidal neovascular membrane. As with diabetic retinopathy, the neovascularization is fragile and tends to break and bleed causing a scar. If the subretinal neovascularization is outside the macula it can be treated with either Focal laser photocoagulation or Photodynamic Therapy. If the neovascularization occurs within the macula, most Ophthalmologists would only consider using Photodynamic Therapy.
Laser Eye Surgery for Age Related Macular Degeneration aims to obliterate the subretinal neovascular membranes that form prior to their bleeding so as to prevent bleeding and scar formation. Once bleeding has occurred, laser eye surgery for AMD is not usually useful.
Laser Eye Surgery for Glaucoma
Glaucoma is an eye disease that is typically associated with pressure in the eye that results in damage to the optic nerve and ultimately vision loss. Glaucoma is usually a disease in which patients have no real symptoms until its late stages. In reality glaucoma is a group of optic nerve diseases. In fact there are many types of glaucoma, some of which are particularly well treated with different types of laser eye surgery.
Primary Open Angle Glaucoma
Primary open angle glaucoma (POAG) is the most common of all types of glaucoma. Patients are usually treated with eye drops and sometimes with oral medications first. If the eye drops or oral medication do not control the pressure in the eye, laser eye surgery may be the best treatment option. Some Ophthalmologists now prefer to use a type of laser eye surgery called Argon Laser Trabeculoplasty (ALT) as a first step either before or along with medications.
Angle Closure Glaucoma
Angle closure glaucoma occurs because of poor anatomy of the space between the cornea and iris, called the trabecular meshwork. This meshwork is the area where aqueous fluid drains. If the space or angle is too narrow it will block the drainage and cause angle closure glaucoma.
A laser eye surgery procedure called a laser iridotomy in which a laser is used to create a small opening or hole in the iris that allows the aqueous fluid to drain.
Normal Pressure Glaucoma (Low-Tension Glaucoma)
Normal pressure glaucoma, also known as low-tension glaucoma, occurs in approximately one-third of all patients afflicted with glaucoma. This type of glaucoma results in the same type of damage to the optic nerve and creates the same type of vision loss but patients are not found to have high pressures. It is believed to be the result of poor pressure in the blood vessels that nourish the optic nerve. While some Ophthalmologists may use eye drops to treat this type of glaucoma, others suggest the laser eye surgery technique called Argon Laser Trabeculoplasty (ALT) in order to avoid the side effects and costs of medications.
Pigmentary glaucoma is a form of glaucoma that usually presents in young males, 20 to 50 years old who are nearsighted and of African-America heritage. Pigmentary glaucoma is caused by chaffing of the iris as it rubs against the structures supporting the lens in your eye. This releases pigment that obstructs the flow of aqueous and causes the pressure in the eye to rise. Pigmentary glaucoma has the best response to the laser eye surgery procedure Argon Laser Trabeculoplasty (ALT) of any type of glaucoma.
Neovascular glaucoma is a form of glaucoma that most commonly occurs in conjunction with Proliferative Diabetic Retinopathy or after a Central Retinal Vein Occlusion that results in neovascularization. The new blood vessels can actually block the drainage of fluid from the eye. Laser eye surgery to obliterate the new vessels on the surface of the iris is not effective. However, when the patient has a Pan Retinal Photocoagulation for the retinal neovascularization, often the iris vessels will regress and the pressure will normalize. If that does not produce the desired results, a laser eye surgery procedure called Laser Cyclophotocoagulation, can be used to obliterate part of the ciliary body so that it no longer produces fluid.
Thus, there are many types of glaucoma. The information provided is an overview of those types of glaucoma that may be successfully treated with various types of laser eye surgery. In addition there are two other types of laser eye surgery that have come into recent favor for the treatment of glaucoma. Endoscopic Cyclophotocoagulation (ECP) allows the laser surgeon to view the ciliary body through an endoscopic camera and apply the laser energy to treat the ciliary body so it reduces or stops the production of fluid. Selective Laser Trabeculoplasty (SLT) is a method of laser eye surgery that allows the laser surgeon to only obliterate very specific target cells in the trabecular meshwork, increasing the ability of the meshwork to drain the aqueous fluid and thus reducing pressure. These laser eye surgery techniques are growing in use and will hopefully prove themselves over time.
Laser Eye Surgery for Cataracts
Modern cataract and lens implant surgery is one of the most successful surgeries that can be performed today. Cataracts are removed using an advanced technique called phacoemulsification whereby the cataract is broken into small pieces and gently suctioned through a tiny incision. In about 20% of patients, the membrane that is left in place to help support the intraocular lens implant may become hazy or cloudy. This may cause the vision may be blurred, hazy, or can cause glare. This is not a recurrence of the cataract, as once they are removed they never return. Fortunately this hazing or cloudiness of the membrane, which is called the posterior capsule, is easily treatable with laser eye surgery and nearly always restores or improves vision. The laser eye procedure called a YAG Laser Capsulotomy or "YAG" is performed right in the Ophthalmologist's office with just a few drops to make you more comfortable. The improved visual results are virtually immediate.
Laser Eye Surgery has indeed opened up the possibilities for patients to reduce their dependence on eyeglasses and contact lenses with LASIK as well as preserve their vision through advanced treatment options for diabetic retinopathy, age related macular degeneration, glaucoma and cataracts.