Macular degeneration is an eye condition characterized by deterioration of the macula and concomitant decrease of vision. There are several types of the disorder. The most common is age-related macular degeneration, but there are congenital forms, seen in younger people.
Presentation
In the early stages, the disease does not showcase any signs and symptoms. The following are the signs and symptoms of macular degeneration [7]:
Eyes
- Visual Impairment
Age-related macular degeneration is a leading cause of visual impairment and severe vision loss. Clinically, it is classified as early-stage (medium-sized drusen and retinal pigmentary changes) to late-stage (neovascular and atrophic). [ncbi.nlm.nih.gov]
[…] title=Category:Macular_degeneration&oldid=357348874" Categories: Macular disorders Aging-associated diseases Visual impairment Non-topical/index: Uses of Wikidata Infobox [commons.wikimedia.org]
Even individuals under the age of 50 years can suffer early forms of AMD It is widely accepted that age-related macular degeneration (AMD) is the most common cause of visual impairment and blindness in industrialized countries. [vision-research.eu]
- Blurred Vision
Increasing amounts of these deposits can cause blurred vision, most noticeable when reading. Both dry and wet macular degeneration can cause blurred vision, but wet AMD more often causes the sudden onset of distortions. [vmrinstitute.com]
Definition (CHV) A condition in which parts of the eye cells degenerate, resulting in blurred vision and ultimately blindness Definition (CHV) A condition in which parts of the eye cells degenerate, resulting in blurred vision and ultimately blindness [fpnotebook.com]
Often this blurred vision will go away in brighter light. People may also see a small but growing blind spot in their field of vision. The vision changes for dry AMD tend to develop slowly. If only one eye is affected, the other may compensate. [yoursightmatters.com]
It causes blurred vision and even loss of vision in the middle of what you would normally see. This makes it hard to drive, to read and to see people’s faces. In severe cases the person may become legally blind. [healthdirect.gov.au]
- Scotoma
Each participant will have their scotomas mapped using a Nidek MP-1 microperimeter housed in the psychology department to give ... [centerwatch.com]
No significant correlation was found between performance for scene categorization and clinical variables such as visual acuity, type of AMD, size of the scotoma, and size of the lesion. [ncbi.nlm.nih.gov]
Its usefulness is limited by the size and location of the “neovascular membrane” (abnormal blood vessels) as a large scotoma may develop within the central vision. [retinaeyedoctor.com]
Central blind spots (scotomas) usually occur late in the disease and can sometimes become severe. Symptoms are usually bilateral. [msdmanuals.com]
- Central Scotoma
Head Mounted Eye Tracking Aide for Loss of Central Vision (HETALCEV) Participants with bilateral central scotomas will be selected for this study during their routine clinical visits at the University of Minnesota Eye Clinic. [centerwatch.com]
Photos by National Eye Institute All the above symptoms may be present, and also the following: metamorphopsia, in which straight lines appear crooked or wavy a blind spot in the central vision (central scotoma) that will get bigger without treatment [medicalnewstoday.com]
scotoma: Visual blind spots that become larger if they are left untreated. [healthengine.com.au]
There may also be central scotomas, shadows or missing areas of vision Slow recovery of visual function after exposure to bright light (photostress test) Visual acuity drastically decreasing (two levels or more), e.g.: 20/20 to 20/80 Blurred vision: Those [en.wikipedia.org]
- Visual Acuity Decreased
Visual acuity decreased to 20/32 in the left eye. Fundus examination revealed stable confluent drusen without any apparent fluid, blood, or lipid. [ncbi.nlm.nih.gov]
Workup
At the preliminary level, a thorough examination of the eyes will be carried out. With the help of eye drops, the pupils will be dilated which will aid in better examination. In addition, the following tests will be carried out to diagnose the type of macular degeneration that has set in [8]:
- Amsler grid: In this, individuals with macular degeneration can see straight lines as wavy, which confirm the condition.
- Fundus photography: This method involves taking images of the inner part of the eye that enables viewing the drusen spots.
- Optical coherence tomography: Is a method which involves the use of light waves to view the retina.
- Fluorescein angiogram: This method enables studying the blood flow to the retina using specialized dye and camera [9].
Visual Field Test
- Central Scotoma
Head Mounted Eye Tracking Aide for Loss of Central Vision (HETALCEV) Participants with bilateral central scotomas will be selected for this study during their routine clinical visits at the University of Minnesota Eye Clinic. [centerwatch.com]
Photos by National Eye Institute All the above symptoms may be present, and also the following: metamorphopsia, in which straight lines appear crooked or wavy a blind spot in the central vision (central scotoma) that will get bigger without treatment [medicalnewstoday.com]
scotoma: Visual blind spots that become larger if they are left untreated. [healthengine.com.au]
There may also be central scotomas, shadows or missing areas of vision Slow recovery of visual function after exposure to bright light (photostress test) Visual acuity drastically decreasing (two levels or more), e.g.: 20/20 to 20/80 Blurred vision: Those [en.wikipedia.org]
Treatment
Severe and advanced cases of macular degeneration cannot be cured. However, if the disease has been diagnosed in the early stages, then with the help of medications, supplements and therapies, the progression can be slowed down, but the lost vision cannot be restored. The following methods are employed for treating macular degeneration:
- Age-Related Eye Disease Study (AREDS) formulation: In this, a combination of supplements is administered to individuals with macular degeneration. 500 mg of vitamin C, 80 mg of zinc, 400 IU of beta carotene and 2 mg of copper are recommended [10].
- Laser photocoagulation therapy: This method is employed fror destruction of abnormal blood cells using light beam.
- Photodynamic therapy: A drug known as verteporfin, is injected intravenously, and is activated by light, which then destroys the leaking blood vessels.
- Aids: In this, affected individuals are given vision aids to make proper and effective use of the vision.
Prognosis
Macular degeneration never causes loss of peripheral vision. This further indicates that complete vision loss never sets in. The loss of central vision that occurs makes driving, reading and recognizing faces difficult for the affected individuals. With treatment, individuals can carry out the daily tasks with ease.
Etiology
The exact cause behind development of macular degeneration is not known. However, several risk factors have been identified. These include [2]:
- Age: The chances of developing macular degeneration increase with advancing age. The older aged populations are more prone to contract this eye disorder.
- Heredity: Individuals with family history of macular degeneration, are at an increased risk of developing the same.
- Smoking and alcohol: Individuals, who have been smoking and drinking, for several years down the line, are more prone to develop macular degeneration [3].
- Chronic degenerative diseases such as hypertension and obesity increase the chances of macular degeneration. In addition, elevated cholesterol levels also predispose an individual to develop macular degeneration.
- Ethnicity: It has been reported that the prevalence of age-related macular degeneration is higher amongst the White than Black. Genetic factors are thought to play a role for such a peculiar trend.
Epidemiology
It has been estimated that age-related macular degeneration is the 3rd most common cause of blindness across the globe. Amongst the industrialized nations, it is considered to be the leading cause of blindness [4]. Statistics have also reported that in the year 2030, about 6.3 millions individuals of US will develop macular degeneration. Of the two types of macular degeneration, 85 to 90% cases account for the dry type; whereas 10 to 15% of cases are of wet type [5].
Pathophysiology
Anatomically, 3 major layers are situated at the back of the eye. These include the retina, choroid and sclera. Damage to the retina causes vision loss, which in the central region of the visual field is known as macula. Such an event induces development of macular degeneration.
Dry form of macular degeneration occurs, when the cellular debris also known as drusen, builds up between the retina and choroid. This causes the retina to detach giving rise to vision problems.
Wet form of macular degeneration sets in when blood vessels from the choroid layer grow behind the retina. As a result, the retina becomes detached, causing vision loss. It is a more severe form of macular degeneration than the dry form [6].
Prevention
Following a healthy lifestyle, can to a certain extent, help in prevention of macular degeneration. Maintaining a healthy weight, and eating healthy diet, rich in vitamins and minerals, would help keep chronic disease at bay, which would eventually prevent the onset of macular degeneration. Individuals are also advised to avoid smoking, and alcohol consumption, which are risk factors of macular degeneration.
Summary
Macular degeneration is a condition characterized by loss of central vision due to damage of the retina. Such a condition makes reading and writing difficult for the affected individuals. It is a common phenomenon amongst the older adults, and therefore the condition is also referred to as age-related macular degeneration [1]. However, there have been instances, when younger individuals too fall prey to the condition, and in such cases, the condition can be congenital macular degeneration. There are 2 types of macular degeneration – wet and dry.
Patient Information
Definition
Macular degeneration is a chronic eye disorder, characterized by central loss of vision, due to damage to the retina. Such a type of condition, however, in rare cases, causes complete loss of vision. Affected individuals find difficulty in reading and recognizing faces.
Cause
The exact factor that causes macular degeneration is unknown. However, several risk factors such as smoking, heredity, alcohol abuse, oxidative stress and chronic degenerative diseases, increase the chances of developing macular degeneration.
Symptoms
Blurred vision is a classical symptom of macular degeneration. In addition, individuals also experience difficulty in driving, reading, differentiating colors and recognizing faces.
Diagnosis
Diagnosis is made by preliminary examination of the eye, with the help of drops to dilate the pupil. Following this, several other tests such as amsler grid test, fundus photography, optical coherence tomography and fluorescein angiogram are also carried out.
Treatment
A combination of treatment regime is employed to effectively manage the condition. Lost vision cannot be restored, and goal of treatment is, to effectively use the remaining vision. Vitamin and mineral supplements are given along with laser surgery or photodynamic therapy.
References
- Hyman L. Epidemiology of eye disease in the elderly. Eye (Lond) 1987; 1 ( Pt 2):330.
- Smith W, Assink J, Klein R, et al. Risk factors for age-related macular degeneration: Pooled findings from three continents. Ophthalmology 2001; 108:697.
- Seddon JM, George S, Rosner B. Cigarette smoking, fish consumption, omega-3 fatty acid intake, and associations with age-related macular degeneration: the US Twin Study of Age-Related Macular Degeneration. Arch Ophthalmol 2006; 124:995.
- Bressler NM. Age-related macular degeneration is the leading cause of blindness. JAMA 2004; 291:1900.
- Jonas JB, Bourne RR, White RA, et al. Visual impairment and blindness due to macular diseases globally: a systematic review and meta-analysis. Am J Ophthalmol 2014; 158:808.
- Young RW. Pathophysiology of age-related macular degeneration. Surv Ophthalmol 1987; 31:291.
- Jager RD, Mieler WF, Miller JW. Age-related macular degeneration. N Engl J Med 2008; 358:2606.
- Ferris FL, Davis MD, Clemons TE, et al. A simplified severity scale for age-related macular degeneration: AREDS Report No. 18. Arch Ophthalmol 2005; 123:1570.
- Holz FG, Jorzik J, Schutt F, et al. Agreement among ophthalmologists in evaluating fluorescein angiograms in patients with neovascular age-related macular degeneration for photodynamic therapy eligibility (FLAP-study). Ophthalmology 2003; 110:400.
- Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol 2001; 119:1417.