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Signs and symptoms of macular degeneration include:
- Visual symptoms
- Distorted vision in the form of metamorphopsia, in which a grid of straight lines appears wavy and parts of the grid may appear blank: Patients often first notice this when looking at things like miniblinds in their home or telephone poles while driving. 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 with nonexudative macular degeneration may be asymptomatic or notice a gradual loss of central vision, whereas those with exudative macular degeneration often notice a rapid onset of vision loss (often caused by leakage and bleeding of abnormal blood vessels).
- Trouble discerning colors, specifically dark ones from dark ones and light ones from light ones
- A loss in contrast sensitivity
Macular degeneration by itself will not lead to total blindness. For that matter, only a very small number of people with visual impairment are totally blind. In almost all cases, some vision remains, mainly peripheral. Other complicating conditions may possibly lead to such an acute condition (severe stroke or trauma, untreated glaucoma, etc.), but few macular degeneration patients experience total visual loss.
The area of the macula comprises only about 2.1% of the retina, and the remaining 97.9% (the peripheral field) remains unaffected by the disease. Even though the macula provides such a small fraction of the visual field, almost half of the visual cortex is devoted to processing macular information.
The loss of central vision profoundly affects visual functioning. It is quite difficult, for example, to read without central vision. Pictures that attempt to depict the central visual loss of macular degeneration with a black spot do not really do justice to the devastating nature of the visual loss. This can be demonstrated by printing letters six inches high on a piece of paper and attempting to identify them while looking straight ahead and holding the paper slightly to the side. Most people find this difficult to do.
Intermediate AMD is diagnosed by large drusen and/or any retinal pigment abnormalities. Intermediate AMD may cause some vision loss, however, like Early AMD, it is usually asymptomatic.
The most common sign at presentation is leukocoria (abnormal white reflection of the retina). Symptoms typically begin as blurred vision, usually pronounced when one eye is closed (due to the unilateral nature of the disease). Often the unaffected eye will compensate for the loss of vision in the other eye; however, this results in some loss of depth perception and parallax. Deterioration of sight may begin in either the central or peripheral vision. Deterioration is likely to begin in the upper part of the vision field as this corresponds with the bottom of the eye where blood usually pools. Flashes of light, known as photopsia, and floaters are common symptoms. Persistent color patterns may also be perceived in the affected eye. Initially, these may be mistaken for psychological hallucinations, but are actually the result of both retinal detachment and foreign fluids mechanically interacting with the photoreceptors located on the retina.
One early warning sign of Coats' disease is yellow-eye in flash photography. Just as the red-eye effect is caused by a reflection off blood vessels in the back of a normal eye, an eye affected by Coats' will glow yellow in photographs as light reflects off cholesterol deposits. Children with yellow-eye in photographs are typically advised to immediately seek evaluation from an optometrist or ophthalmologist, who will assess and diagnose the condition and refer to a vitreo-retinal specialist.
Coats' disease itself is painless. Pain may occur if fluid is unable to drain from the eye properly, causing the internal pressure to swell, resulting in painful glaucoma.
Coats' usually affects only one eye (unilateral) and occurs predominantly in young males 1/100,000, with the onset of symptoms generally appearing in the first decade of life. Peak age of onset is between 6–8 years of age, but onset can range from 5 months to 71 years.
Coats' disease results in a gradual loss of vision. Blood leaks from the abnormal vessels into the back of the eye, leaving behind cholesterol deposits and damaging the retina. Coats' disease normally progresses slowly. At advanced stages, retinal detachment is likely to occur. Glaucoma, atrophy, and cataracts can also develop secondary to Coats' disease. In some cases, removal of the eye may be necessary (enucleation).
A rhegmatogenous retinal detachment is commonly preceded by a posterior vitreous detachment which gives rise to these symptoms:
- flashes of light (photopsia) – very brief in the extreme peripheral (outside of center) part of vision
- a sudden dramatic increase in the number of floaters
- a ring of floaters or hairs just to the temporal (skull) side of the central vision
Although most posterior vitreous detachments do not progress to retinal detachments, those that do produce the following symptoms:
- a dense shadow that starts in the peripheral vision and slowly progresses towards the central vision
- the impression that a veil or curtain was drawn over the field of vision
- straight lines (scale, edge of the wall, road, etc.) that suddenly appear curved (positive Amsler grid test)
- central visual loss
In the event of an appearance of sudden flashes of light or floaters, an eye doctor needs to be consulted immediately. A shower of floaters or any loss of vision, too, is a medical emergency.
"Typical lattice" consists of sharply demarcated, spindle-shaped areas of retinal thinning, usually located between the equator of the retina and the posterior border of the vitreous base. This is more frequently located in the temporal half of the retina and is seen more superiorly than inferiorly.
"Atypical lattice" is characterised by radial lesions which appear continuous with the peripheral blood vessels. This type is typically seen in patients with Stickler syndrome.
Optic nerve damage is progressive and insidious. Eventually 75% of patients will develop some peripheral field defects. These can include nasal step defects, enlarged blind spots, arcuate scotomas, sectoral field loss and altitudinal defects. Clinical symptoms correlate to visibility of the drusen. Central vision loss is a rare complication of bleeding from peripapillar choroidal neovascular membranes. Anterior ischemic optic neuropathy (AION) is a potential complication.
Patients with Stargardt disease usually develop symptoms in the mid-first to the late second decade of life, with age of onset which can be as early as ~6 years of age. The main symptom of Stargardt disease is loss of visual acuity, uncorrectable with glasses, which progresses and frequently stabilizes between 20/200 and 20/400. Other symptoms include wavy vision, blind spots (scotomata), blurriness, impaired color vision, and difficulty adapting to dim lighting (delayed dark adaptation). The disease sometimes causes sensitivity to glare; overcast days offer some relief. Vision is most noticeably impaired when the macula (center of retina and focus of vision) is damaged, leaving peripheral vision more intact. Generally, vision loss starts within the first 20 years of life.
Examination with an ophthalmoscope shows few notable findings in the early stages of the disease. Eventually, however, an oval-shaped atrophy with a horizontal major axis appears in the retinal pigment epithelium, and has the appearance of beaten bronze, along with sparing of the area surrounding the optic disc (peripapillary sparing). Techniques such as fundus autofluorescence (FAF), Optical Coherence Tomography (OCT), or less frequently fluorescein angiography, can detect early signs before they are visible ophthalmoscopically.
In most patients, optic disc drusen are an incidental finding. It is important to differentiate them from other conditions that present with optic disc elevation, especially papilledema, which could imply raised intracranial pressure or tumors. True papilledema may present with exudates or cotton-wool spots, unlike ODD. The optic disc margins are characteristically irregular in ODD but not blurred as there is no swelling of the retinal nerve fibers. Spontaneous venous pulsations are present in about 80 percent of patients with ODD, but absent in cases of true disc edema. Other causes of disc elevation clinicians must exclude may be: hyaloid traction, epipapillary glial tissue, myelinated nerve fibres, scleral infiltration, vitreopapillary traction and high hyperopia. Disorders associated with disc elevation include: Alagille syndrome, Down syndrome, Kenny-Caffey syndrome, Leber Hereditary Optic Neuropathy and linear nevus sebaceous syndrome.
Geographic atrophy (GA) is a chronic disease, which leads to visual function loss. This often results in difficulties performing daily tasks such as reading, recognizing faces, and driving, and ultimately has severe consequences on independence.
Initially, patients often have good visual acuity if the GA lesions are not involved in the central macular, or foveal, region of the retina. As such, a standard vision test may underrepresent the visual deficit experienced by patients who report challenges reading, driving or seeing in low light conditions.
Lattice degeneration is a disease of the human eye wherein the peripheral retina becomes atrophic in a lattice pattern and may develop tears, breaks, or holes, which may further progress to retinal detachment. It is an important cause of retinal detachment in young myopic individuals. The cause is unknown, but pathology reveals inadequate blood flow resulting in ischemia and fibrosis.
Lattice degeneration occurs in approximately 6–8% of the general population and in approximately 30% of phakic retinal detachments. Similar lesions are seen in patients with Ehlers-Danlos syndrome, Marfan syndrome, and Stickler syndrome, all of which are associated with an increased risk of retinal detachment. Risk of developing lattice degeneration in one eye is also increased if lattice degeneration is already present in the other eye.
The first symptom of this disease is usually a slow loss of vision. Early signs of Retinitis include loss of night vision; making it harder to drive at night. Later signs of retinitis include loss of peripheral vision, leading to tunnel vision. In some cases, symptoms are experienced in only one of the eyes. Experiencing the vision of floaters, flashes, blurred vision and loss of side vision in just one of the eyes is an early indication of the onset of Retinitis.
Geographic Atrophy (GA), also known as atrophic age-related macular degeneration (AMD) or advanced dry AMD, is an advanced form of age-related macular degeneration that can result in the progressive and irreversible loss of retina (photoreceptors, retinal pigment epithelium, choriocappillaris) which can lead to a loss of visual function over time. It is estimated that GA affects >5 million people worldwide and approximately 1 million patients in the US, which is similar to the prevalence of neovascular (wet) AMD, the other advanced form of the disease.
The incidence of advanced AMD, both geographic atrophy and neovascular AMD, increases exponentially with age and while there are therapies for wet AMD, GA currently has no approved treatment options. The aim of most current clinical trials is to reduce the progression of GA lesion enlargement.
When this occurs there is a characteristic pattern of symptoms:
- Flashes of light (photopsia)
- A sudden dramatic increase in the number of floaters
- A ring of floaters or hairs just to the temporal side of the central vision
As a posterior vitreous detachment proceeds, adherent vitreous membrane may pull on the retina. While there are no pain fibers in the retina, vitreous traction may stimulate the retina, with resultant flashes that can look like a perfect circle.
If a retinal vessel is torn, the leakage of blood into the vitreous cavity is often perceived as a "shower" of floaters. Retinal vessels may tear in association with a retinal tear, or occasionally without the retina being torn.
Retinoschisis is an eye disease characterized by the abnormal splitting of the retina's neurosensory layers, usually in the outer plexiform layer. Most common forms are asymptomatic, some rarer forms result in a loss of vision in the corresponding visual field.
This type of retinoschisis is very common with a prevalence of up to 7 percent in normal persons. Its cause is unknown. It can easily be confused with retinal detachment by the non-expert observer and in difficult cases even the expert may have difficulty differentiating the two. Such differentiation is important since retinal detachment almost always requires treatment while retinoschisis never itself requires treatment and leads to retinal detachment (and hence to visual loss) only occasionally. Unfortunately one still sees cases of uncomplicated retinoschisis treated by laser retinopexy or cryopexy in an attempt to stop its progression towards the macula. Such treatments are not only ineffective but unnecessarily risk complications. There is no documented case in the literature of degenerative retinoschisis itself (as opposed to the occasional situation of retinal detachment complicating retinoschisis) in which the splitting of the retina has progressed through the fovea. There is no clinical utility in differentiating between typical and reticular retinoschisis. Degenerative retinoschisis is not known to be a genetically inherited condition.
There is always vision loss in the region of the schisis as the sensory retina is separated from the ganglion layer. But like the loss is in the periphery, it goes unnoticed. It is the very rare schisis that encroaches on the macula where retinopexy is then properly used.
Progressive retinal atrophy (PRA) is a group of genetic diseases seen in certain breeds of dogs and, more rarely, cats. Similar to retinitis pigmentosa in humans, it is characterized by the bilateral degeneration of the retina, causing progressive vision loss culminating in blindness. The condition in nearly all breeds is inherited as an autosomal recessive trait, with the exception of the Siberian Husky (inherited as an X chromosome linked trait) and the Bullmastiff (inherited as an autosomal dominant trait). There is no treatment.
In general, PRAs are characterised by initial loss of rod photoreceptor cell function followed by that of the cones and for this reason night blindness is the first significant clinical sign for most dogs affected with PRA. As other retinal disorders, PRA can be divided into either dysplastic disease, where the cells develop abnormally, and degenerative, where the cells develop normally but then degenerate during the dog's lifetime.
Generalized PRA is the most common type and causes atrophy of all the neural retinal structures. Central progressive retinal atrophy (CPRA) is a different disease from PRA involving the retinal pigment epithelium (RPE), and is also known as retinal pigment epithelial dystrophy (RPED).
Many people often do not have symptoms until very late in their disease course. Patients often become symptomatic when there is irreversible damage. Symptoms are usually not painful and can include:
- Vitreous hemorrhage
- Floaters, or small objects that drift through the field of vision
- Decreased visual acuity
- "Curtain falling" over eyes
The most common symptoms of cone dystrophy are vision loss (age of onset ranging from the late teens to the sixties), sensitivity to bright lights, and poor color vision. Therefore, patients see better at dusk. Visual acuity usually deteriorates gradually, but it can deteriorate rapidly to 20/200; later, in more severe cases, it drops to "counting fingers" vision. Color vision testing using color test plates (HRR series) reveals many errors on both red-green and blue-yellow plates.
A cone dystrophy is an inherited ocular disorder characterized by the loss of cone cells, the photoreceptors responsible for both central and color vision.
The risk of retinal detachment is greatest in the first 6 weeks following a vitreous detachment, but can occur over 3 months after the event.
The risk of retinal tears and detachment associated with vitreous detachment is higher in patients with myopic retinal degeneration, lattice degeneration, and a familial or personal history of previous retinal tears/detachment.
Retinal detachment is a disorder of the eye in which the retina separates from the layer underneath. Symptoms include an increase in the number of floaters, flashes of light, and worsening of the outer part of the visual field. This may be described as a curtain over part of the field of vision. In about 7% of cases both eyes are affected. Without treatment permanent loss of vision may occur.
The mechanism most commonly involves a break in the retina that then allows the fluid in the eye to get behind the retina. A break in the retina can occur from a posterior vitreous detachment, injury to the eye, or inflammation of the eye. Other risk factors include being short sighted and previous cataract surgery. Retinal detachments also rarely occur due to a choroidal tumor. Diagnosis is by either looking at the back of the eye with an ophthalmoscope or by ultrasound.
In those with a retinal tear, efforts to prevent it becoming a detachment include cryotherapy using a cold probe or photocoagulation using a laser. Treatment of retinal detachment should be carried out in a timely manner. This may include scleral buckling where silicone is sutured to the outside of the eye, pneumatic retinopexy where gas is injected into the eye, or vitrectomy where the vitreous is partly removed and replaced with either gas or oil.
Retinal detachments affect between 0.6 and 1.8 people per 10,000 per year. About 0.3% of people are affected at some point in their life. It is most common in people who are in their 60s or 70s. Males are more often affected than females. The long term outcomes depend on the duration of the detachment and whether the macula was detached. If treated before the macula detaches outcomes are generally good.
Stargardt disease, or fundus flavimaculatus, is the most frequent form of inherited juvenile macular degeneration. Stargardt causes progressive vision loss usually to the point of legal blindness. Several genes are associated with the disorder. Symptoms, mainly central vision loss, typically develop before age 20 (median age of onset: ~17 years old), and also include wavy vision, blind spots, blurriness, impaired color vision, and difficulty adapting to dim lighting (dark adaptation delays).
Stargardt is often used to refer to any juvenile macular dystrophy; however, it properly refers to atrophic macular dystrophy with yellow, poorly-defined flecks surrounding the macula in the retinal pigment epithelium.
Vitelliform macular dystrophy or vitelliform dystrophy is an irregular autosomal dominant eye disorder which can cause progressive vision loss. This disorder affects the retina, specifically cells in a small area near the center of the retina called the macula. The macula is responsible for sharp central vision, which is needed for detailed tasks such as reading, driving, and recognizing faces. The condition is characterized by yellow (or orange), slightly elevated, round structures similar to the yolk (Latin "vitellus") of an egg.