CATARACTS
Cataracts are the leading cause of blindness worldwide, with over 42 million impacted by this condition. While they are very common, cataracts are one of most treatable causes of diminished vision in areas where patients have access to eye care.
Who develops cataracts?
Cataracts can occur at any age, but are especially common in adults over 65 years of age. By age 65 years, about half of Americans begin to develop cataracts. This rate is even higher in women than in men. While cataracts are fairly common, there are some strategies that can help prevent the development of this eye condition.
What is a cataract?
The lens of the eye helps to focus light so that we can see clearly. The lens is made up of crystallin proteins which can lose their shape and structure due to damage from free radicals over time. This can cause these proteins to clump together and form an opacity or cataract. This opacity develops inside the normally transparent lens which allows less light to enter the eye and therefore diminishes vision. A cataract can form in different layers of the lens.
What are the causes and risk factors for cataracts?
Many different risk factors have been linked to the development of cataracts. These include:
· Free-radical damage from environmental sources like sunlight, smoking, stress, etc.
· Head & eye injury & systemic chronic diseases
· Side effects of prescription drugs & chemicals
· Steroids like prednisone in any form
· Photosensitizing drugs: antibiotics, gout meds, cholesterol-lowering agents, diuretics (i.e. thiazides)
· Diabetes
· Obesity & increased fat in the diet
· Excessive alcohol consumption
· Heredity
· Aging of the eye with changing curvature of lens
· Poor nutrition & poor digestion: Nutritional deficiencies cause cataracts to develop earlier & progress faster
What are some symptoms of cataracts?
In a healthy eye, the flexible, transparent lens focuses light onto the retina at the back of the eye, which absorbs the transmitted light and sends this message through the optic nerve to the brain, allowing us to see an image. With cataracts, light which enters the eye is scattered causing several possible symptoms. These include:
· Loss of night vision
· Glare
· Blurry or hazy vision, noticed first at distance
· Halos around lights
· Glasses always seem dirty
· Fatigue with reading
· Inability to perform fine tasks like threading a needle
· Inability to judge distance or steps
· Poor depth perception
· Development of “second sight” if the cataract grows in a way that one’s vision shifts so either distance or near vision becomes clearer without glasses than before the cataract developed
How are cataracts diagnosed?
The best way to detect and diagnose cataracts is to have regular dilated eye examinations with slit lamp examination from a qualified health professional. Normally, a red reflex is seen when light is reflected evenly back from retina. When a cataract develops, it appears as a dark silhouette within the red reflex. An eye care professional can exam your eyes and detect if a cataract is present.
How are cataracts treated?
With cataracts, the function of the eye and a patient’s visual experience are more important than the simple presence of a cataract. If a patient can see and function well visually, removal of the cataract is not always immediately necessary.
When treatment is needed, there are various options. Early in the development of a cataract, glasses prescriptions may need adjustment. There are also dietary and lifestyle changes that can help prevent and slow the progression of cataract development. Once a cataract is sufficiently interfering with a patient’s vision, surgery using phacoemulsification may be needed. This technique using ultrasound waves to break-up the hard cataract which can then be vacuumed out of the eye. The procedure is generally quick and can often be performed with local anesthesia at an outpatient surgery center. Generally, stitches and eye patches may not be needed, and patients can often drive and life and bend as soon as one day after surgery.
How can cataracts be prevented?*
In most individuals, cataracts are not inevitable. Several lifestyle and diet changes can help prevent or slow the progression of cataracts.
· Ultraviolet-filtering sunglasses can help protect the eye from UV light damage
· Avoiding smoking helps to lessen free-radical damage and decrease the risk of cataracts
· A varied diet rich in fruits and vegetables which contain many antioxidants has been demonstrated to prevent the development of cataracts
GLAUCOMA
Glaucoma refers to a collection of diseases which all cause damage to the optic nerve that carries visual information from the eye to the brain. These can therefore result in vision loss. Glaucoma is NOT a disease which is diagnosed based solely on elevated internal eye pressure.
Glaucoma is the second leading cause of blindness in the United States (after diabetic retinopathy) and the leading cause of blindness in African Americans.
What are the symptoms of glaucoma?
Glaucoma commonly presents slowly over time and may not be noticed in its early stages since often only one eye is impacted at a time and/or the peripheral or edges of the vision are commonly impacted first. As the disease progresses, patients may notice a loss of their vision at the edges or periphery of their visual fields.
What causes glaucoma?
The eye is filled with fluid which must remain in balance. This fluid is important for the health of the eye, especially the lens and the cornea. The fluid moves from its source of production behind the iris in the eye to its exit at the angle in front of the iris. If too much fluid is produced or if the fluid cannot drain properly, the pressure inside the eye may become too high. If the pressure in the eye reaches too high of a level, the optic nerve may be damaged and vision can be lost.
Glaucoma results when there is poor drainage or poor circulation of fluid inside the eye. It can also occur when there is poor circulation to the optic nerve or a lack of blood flow to the retina and optic nerve which can result in optic nerve cell death, enlargement of the optic cup and loss of vision.
What are some different types of diseases classified as glaucoma?
• Chronic open-angle glaucoma: this is the most common type of glaucoma in the US; in this type of glaucoma there is plenty of room for the eye fluid to exit but the trabecular meshwork which acts as a filter for eye fluid does not filter fluid well.
• Angle-closure glaucoma: in this type of glaucoma, the base of the iris is too close to the cornea so that the fluid cannot flow freely. This can be chronic but more commonly results in an acute sudden attack of severe eye pain and visual halos.
• Secondary glaucoma: can result from inflammation, injury, blood in eye or steroids.
• Low-tension glaucoma: most often occurs in elderly patients with poor circulation.
• Congenital glaucoma: occurs at birth. Unusual, serious, needs aggressive surgery.
• Ocular hypertension or glaucoma suspect: these patients with higher than normal eye pressure need to be monitored and followed closely by an eye health professional.
What are some risk factors for glaucoma?
• Stress: sustained imbalance between parasympathetic & sympathetic nervous systems
• Hypertension (high blood pressure)
• Low blood pressure (for low-tension glaucoma)
• Hyperthyroidism (over-active thyroid gland)
• Obesity, diabetes
• Smoking, Emphysema
• Cardiovascular/heart disease
• Steroid medications
• African American ethnicity
• Family History of glaucoma
• Extreme nearsightedness (myopia)
• Farsightedness or hyperopia (for angle closure)
• Pigment dispersion (loss of pigment from iris splashes onto back of cornea & into trabecular meshwork)
• Psuedo-exfoliation
• Nerve fiber defects
How is glaucoma diagnosed?
A professional eye exam with specialized testing is the best way to detect glaucoma. An eye care professional will review a patient’s risk factors and perform a clinical dilated eye exam, including measurement of intraocular eye pressure, examination of optic nerves and computerized exam of visual fields if glaucoma is suspected. Those at high risk for glaucoma, such as African Americans, may need yearly testing beginning at 35 years of age or earlier depending on family history and individual risk factors.*
How is glaucoma treated?*
Glaucoma is treated in varying ways depending on the individual type and other health concerns. There are several medications that may be used and/or surgery or laser treatments that may help some types of glaucoma.
How can the risk of glaucoma be reduced?
There are several ways that some health care professionals believe can help prevent the risk of glaucoma.* These include:
· Relaxation: meditate, Tai Chi, yoga, walks, visual imagery, yoga, etc.
o Dealing with stress appropriately is key
· Exercise:
o 30-40 minutes of walking each day was shown to be equivalent to taking a daily medication for glaucoma in one study
· Digestion and good nutrition: important for health of parasympathetic nervous system
MACULAR DEGENERATION
Age-related macular degeneration (AMD) is a leading cause of blindness in the United States among those aged 65 years and older. This condition impacts over 14 million Americans, and develops after a lifetime of damage to the center of the retina known as the macula. The macula is the center of the retina or area of the eye that helps transmit the light signal that enters the eye to the brain so that we can see images.
AMD may develop painlessly and gradually with little warning or acutely with rapid loss of vision. The wet form of AMD occurs in around 10% of patients when blood vessels in the retina grow new offshoots which can bleed and cause scarring and damage that may result in sudden, rapid loss of vision. The dry form of AMD is more common, occurring in 90% of patients with the disease. This type of AMD develops slowly over time with white deposits called drusen building up in the retina. These drusen are thought to be waste products that accumulate.
What causes macular degeneration?
It is not totally clear why macular degeneration develops in some people. It occurs when the retina or back of the eye and the surrounding tissue which nourishes the retina deteriorate. This can occur when waste products build up over time or the tissue does not have proper nourishment. With age, some of these changes may occur in some people.
What are the symptoms of macular degeneration?
Patients with AMD may develop:
· Blurry vision
· Fading of their ability to see colors
· Dark or empty areas in the center of their vision
· Crooked appearing or bending of normally straight lines and objects
How is macular degeneration diagnosed?
The best way to diagnosis AMD is with a dilated professional eye exam. Special tests such as an Amsler grid may be used to detect the visual changes that can accompany macular degeneration. A qualified eye care professional may perform ophthalmoscopy with a slit lamp exam, fundus photography and/or fluorescein angiography to evaluate the health of the retina depending on the patient and her symptoms.
What are risk factors for macular degeneration?
Many risk factors have been suggested to contribute to the chance of developing macular degeneration. These include:
· Age over 60 years or more than 25 years of exposure to other risk factors
· Family history of macular degeneration
· Light-colored irises (blue, green or hazel)
· Hyperopia (farsightedness)
· Aphakia (lack of a lens in the eye from cataract removed without artificial lens implantation)
· High fat or cholesterol in the diet; elevated serum cholesterol and/or triglycerides
· Hypertension (high blood pressure)
· Heart disease, atherosclerosis
· Osteoporosis
· Smoking (increases risk 2-3 times)
· Postmenopausal status (for females)
· Impaired digestion, reduced nutrient absorption
· Excessive alcohol consumption
· Lack of exercise
· Diabetes
· Obesity
How can macular degeneration be treated?
Treatment varies by the individual patient. Conventionally, there are few treatments for macular degeneration, but many believe that the condition can be prevented and stabilized with diet and lifestyle changes.* These include a diet rich in antioxidants from a variety of fruits and vegetables. The wet form may also be treated with laser photocoagulation surgery to stop retinal bleeding if detected early. There are also other surgical and medication treatments, some of which remain experimental.
*Check with your physician or health care provider before making any changes in your diet or health care routine. This information is not intended to replace a one- on-one relationship with a qualified health care professional and is not intended as medical advice. We encourage you to make your own health care decisions based upon your research and in partnership with a qualified health care professional.
--Jennifer L. Weinberg, MD, MPH, MBE
