In the early stages, the disease does not showcase any signs and symptoms. The following are the signs and symptoms of macular degeneration [7]:

• Blurred vision
• Colors appear faded
• Difficulty in reading 
• Appearance of spot in the center of the vision
• Difficulty in recognizing faces
• Incipient and geographic atrophy
• Appearance of straight lines as curved
• Loss of contrast sensitivity 
• Gradual decrease in visual acuity by 2 or more levels

• Turkish

  PURPOSE: To evaluate the blood lead (Pb) and cadmium (Cd) levels in age related macular degeneration (AMD) in a turkish urban population. [ncbi.nlm.nih.gov]

• 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]

  scotoma) that will get bigger without treatment Symptoms appear and progress more rapidly than with dry AMD. [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]

• Arcus Senilis

  We suspect that these rings are more common than generally appreciated because they may have a subtle appearance or be misdiagnosed as arcus senilis. [ncbi.nlm.nih.gov]

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].

• Chlamydia

  To investigate whether Chlamydia pneumoniae and complement factors were present in surgically removed choroidal neovascular membranes (CNV) of patients with age-related macular degeneration (AMD). [ncbi.nlm.nih.gov]

• 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]

  scotoma) that will get bigger without treatment Symptoms appear and progress more rapidly than with dry AMD. [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]

• Lymphocytic Infiltrate

  The findings of biopsy of erythematous skin on the back revealed lymphocyte infiltration and telangiectasia in the upper dermis, thus confirming the diagnosis. The patient was administered 30 mg prednisolone to resolve the immunoreaction. [ncbi.nlm.nih.gov]

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.

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.

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.

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].

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].

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.

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.

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.

1. Hyman L. Epidemiology of eye disease in the elderly. Eye (Lond) 1987; 1 ( Pt 2):330.
2. Smith W, Assink J, Klein R, et al. Risk factors for age-related macular degeneration: Pooled findings from three continents. Ophthalmology 2001; 108:697.
3. 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.
4. Bressler NM. Age-related macular degeneration is the leading cause of blindness. JAMA 2004; 291:1900.
5. 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.
6. Young RW. Pathophysiology of age-related macular degeneration. Surv Ophthalmol 1987; 31:291.
7. Jager RD, Mieler WF, Miller JW. Age-related macular degeneration. N Engl J Med 2008; 358:2606.
8. 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.
9. 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.
10. 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.