Age-related macular degeneration is the leading cause of severe blindness in the U.S today. The neovascular (wet) type occurs when choroidal vessels penetrate Beuch’s membrane and proliferate beneath the retinal pigment epithelium, leading to choroidal neovascularization, subretinal hemorrhage, and serous retinal detachment. Approximately 10% of patients with age-related macular degeneration develop the wet form, which accounts for the majority of those who become legally blind.1
Etiology:
Erin There are some factors that increase the risk of developing macular degeneration:2
Age - risk increases as age increase. Macular degenerations most commonly occurs over the age of 65.
Family history
Race - more common in caucasians than other races
Smoking - smoking cigarettes increases the risk of developing macular degeneration
Obesity - being severly overweight increases the risk of early or intermediatae macular degeneration progressing into the more severe form
Unhealthy diet - may increase the risk of developing macular degeneration
Cardiovascular disease - history of this has been shown to increase the risk of developing macular degeneration
Elevated cholesterol - may be associated with increased risk
Signs & Symptoms:
Spencer Macular degeneration can occur in either one eye or both eyes.3 Both Eyes:
You may notice the need for more light when doing work or reading.
Having trouble adapting to low levels of light, usually when entering another room.
Increasing of blurriness.
Difficulty recognizing faces.
Crooked central vision.
Having a blurred or blind spots in your vision.
Hallucinations of shapes or people, in advanced cases of macular degeneration.
One Eye:
You may not notice these effects for a while due to the other eye compensating for the weak one.
You start to notice changes in your vision.
Loss of ability to see colors and fine detail.
Diagnostic Procedures:
Pablo Diagnostic test to detect and diagnose macular degeneration include:
Routine eye exam: measurement of the patient’s visual acuity and a dilated exam of the retina
Anguography
Optical coherence tomography (OCT)
Microperimetry: used to quantify macular sensitivity and fixation patterns4
Histology:
Becky
Two forms of macular degeneration: dry (atrophic) and wet (neovacular/exudative).5
Lymph node drainage:
Adam Macular degeneration is a benign disease and does not have lymphatic spread.
Metastatic spread:
Megan Metastatic spread does not occur with benign diseases. This only pertains to the eye.1
Grading:
Kevin Tsai
There is no universally agreed grading system for macular degeneration.
Staging:
Erin Staging for macular degeneration is based on the damage in the eye, and is categorized as early, intermediate, or advanced stage.2
Early Stage - Doctors may detect several small or a few medium-size drusen under the retina in one or both eyes. Generally, no vision loss is experienced in the early stage
Intermediate Stage - Doctors may detect a large number of medium-size or one or more large drusen in one or both eyes. At this stage, no symptoms may appear. However, the central vision may be blurred, or extra lighting may be needed for reading or doing detailed work. It may take longer to recover vision when entering a room that is not well lite.
Advanced Stage - Doctors may detect several large drusen, as well as extensive breakdown of cells in the macula. A well-defined area of blurring may occur in the central vision, which may gradually grow larger.
(Drusen - tiny yellow or white deposits under the retina)
Radiation side effects:
Spencer Although studies have been conducted on using radiation therapy for macular degeneration, it is not the treatment of choice in most instances. From the studies conducted, some radiation side effects seen can include:7
Cataracts
Ocular Irritation
Radiation Retinopathy
Optic Neuropathy
Prognosis:
Pablo Macular degeneration can lead to total blindness if left untreated. Many individuals suffering from such condition will experience the loss of central vision in the affected eye. Peripheral vision will remain if no other eye disease exists. In most cases patients will be able to see enough to get around especially in familiar situations. Macular degeneration is not a life threatening disease.8
6.) Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:180.
7.) Kishan A, Modjtahedi B, Morse L, et al. Radiation Therapy for Neurovascular Age-Related Macular Degeneration. Int Jour Rad Onc. 2012;3(85). doi: 10.1016/j.ijrobp.2012.07.2352.
Age-related macular degeneration is the leading cause of severe blindness in the U.S today. The neovascular (wet) type occurs when choroidal vessels penetrate Beuch’s membrane and proliferate beneath the retinal pigment epithelium, leading to choroidal neovascularization, subretinal hemorrhage, and serous retinal detachment. Approximately 10% of patients with age-related macular degeneration develop the wet form, which accounts for the majority of those who become legally blind.1
There are some factors that increase the risk of developing macular degeneration:2
Macular degeneration can occur in either one eye or both eyes.3
Both Eyes:
One Eye:
Diagnostic test to detect and diagnose macular degeneration include:
Two forms of macular degeneration: dry (atrophic) and wet (neovacular/exudative).5
Macular degeneration is a benign disease and does not have lymphatic spread.
Metastatic spread does not occur with benign diseases. This only pertains to the eye.1
There is no universally agreed grading system for macular degeneration.
Staging for macular degeneration is based on the damage in the eye, and is categorized as early, intermediate, or advanced stage.2
(Drusen - tiny yellow or white deposits under the retina)
Although studies have been conducted on using radiation therapy for macular degeneration, it is not the treatment of choice in most instances. From the studies conducted, some radiation side effects seen can include:7
Macular degeneration can lead to total blindness if left untreated. Many individuals suffering from such condition will experience the loss of central vision in the affected eye. Peripheral vision will remain if no other eye disease exists. In most cases patients will be able to see enough to get around especially in familiar situations. Macular degeneration is not a life threatening disease.8
The relevant TD5/5s are as follows:10
Brain - 4500 cGy (Necrosis)
Lens - 1000 cGy (Cataracts)
Optic chiasm - 4500 cGy (Blindness)
Optic nerve - 5000 cGy (Blindness)
Retina - 4500 (Blindness)
1.) Chao C, Perez C, Brady L. Radiation Oncology Management Decisions. 3rd ed. PA: Lippincott Williams and Wilkins; 2011:782.
2.) Mayo Clinic Website. Dry Macular Degeneration. http://www.mayoclinic.com/health/macular-degeneration/DS00284/DSECTION=risk-facors. Accessed July 10, 2013.
3.) Macular Degeneration. Mayo Clinic Web Site. http://www.mayoclinic.com/health/macular-degeneration/DS00284/DSECTION=symptoms. Accessed July 9, 2013.
4.) Web MD. Web site. http://www.webmd.com/eye-health/macular-degeneration/age-related-macular-degeneration-diagnosis-tests. Accessed July 08, 2013.
5.) Heathplexus Website.www.healthplexus.net/article/classification-age-related-macular- degeneration Accessed July 3, 2013.
6.) Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2002:180.
7.) Kishan A, Modjtahedi B, Morse L, et al. Radiation Therapy for Neurovascular Age-Related Macular Degeneration. Int Jour Rad Onc. 2012;3(85). doi: 10.1016/j.ijrobp.2012.07.2352.
8.) MedicineNet.http://www.medicinenet.com/macular_degeneration/page8.htm#what_is_the_prognosis_for_macular_degeneration. Accessed July 08, 2013.
9.) Macular Degeneration Website. http://www.maculardegeneration.org/enroll.html Accessed July 3, 2013.
10.) Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby Inc; 2010.