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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.
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.
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.
Oguchi disease present with nonprogressive night blindness since young childhood or birth with normal day vision, but they frequently claim improvement of light sensitivities when they remain for some time in a darkened environment.
On examination patients have normal visual fields but the fundos have a diffuse or patchy, silver-gray or golden-yellow metallic sheen and the retinal vessels stand out in relief against the background.
A prolonged dark adaptation of three hours or more, leads to disappearance of this unusual discoloration and the appearance of a normal reddish appearance. This is known as the Mizuo-Nakamura phenomena and is thought to be caused by the overstimulation of rod cells.
The initial retinal degenerative symptoms of retinitis pigmentosa are characterized by decreased night vision (nyctalopia) and the loss of the mid-peripheral visual field. The rod photoreceptor cells, which are responsible for low-light vision and are orientated in the retinal periphery, are the retinal processes affected first during non-syndromic forms of this disease. Visual decline progresses relatively quickly to the far peripheral field, eventually extending into the central visual field as tunnel vision increases. Visual acuity and color vision can become compromised due to accompanying abnormalities in the cone photoreceptor cells, which are responsible for color vision, visual acuity, and sight in the central visual field. The progression of disease symptoms occurs in a symmetrical manner, with both the left and right eyes experiencing symptoms at a similar rate.
A variety of indirect symptoms characterize retinitis pigmentosa along with the direct effects of the initial rod photoreceptor degeneration and later cone photoreceptor decline. Phenomena such as photophobia, which describes the event in which light is perceived as an intense glare, and photopsia, the presence of blinking or shimmering lights within the visual field, often manifest during the later stages of RP. Findings related to RP have often been characterized in the fundus of the eye as the "ophthalamic triad". This includes the development of (1) a mottled appearance of the retinal pigment epithelium (RPE) caused by bone spicule formation, (2) a waxy appearance of the optic nerve, and (3) the attentuation of blood vessels in the retina.
Non-syndromic RP usually presents a variety of the following symptoms:
- Night blindness
- Tunnel vision (due to loss of peripheral vision)
- Latticework vision
- Photopsia (blinking/shimmering lights)
- Photophobia (aversion to glare)
- Development of bone spicules in the fundus
- Slow adjustment from dark to light environments and vice versa
- Blurring of vision
- Poor color separation
- Loss of central vision
- Eventual blindness
Clinically, there is an acute onset of visual loss, first in one eye, and then a few weeks to months later in the other. Onset is usually young adulthood, but age range at onset from 7-75 is reported. The age of onset is slightly higher in females (range 19–55 years: mean 31.3 years) than males (range 15–53 years: mean 24.3). The male to female ratio varies between mutations: 3:1 for 3460 G>A, 6:1 for 11778 G>A and 8:1 for 14484 T>C.
This typically evolves to very severe optic atrophy and a permanent decrease of visual acuity. Both eyes become affected either simultaneously (25% of cases) or sequentially (75% of cases) with a median inter-eye delay of 8 weeks. Rarely only one eye may be affected. In the acute stage, lasting a few weeks, the affected eye demonstrates an edematous appearance of the nerve fiber layer especially in the arcuate bundles and enlarged or telangiectatic and tortuous peripapillary vessels (microangiopathy). The main features are seen on fundus examination, just before or subsequent to the onset of visual loss. A pupillary defect may be visible in the acute stage as well. Examination reveals decreased visual acuity, loss of color vision and a cecocentral scotoma on visual field examination.
Oguchi disease, also called congenital stationary night blindness, Oguchi type 1 or Oguchi disease 1, is an autosomal recessive form of congenital stationary night blindness associated with fundus discoloration and abnormally slow dark adaptation.
There is another retinal disease in Briards known as hereditary retinal dysplasia. These dogs are night blind from birth, and day vision varies. Puppies affected often have nystagmus. It is also known as lipid retinopathy.
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.
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).
"LHON Plus" is a name given to a rare variant of the disorder with eye disease together with other conditions. The symptoms of this higher form of the disease include loss of the brain's ability to control the movement of muscles, tremors, and cardiac arrhythmia. Many cases of LHON plus have been comparable to multiple sclerosis because of the lack of muscular control.
Patients with idiopathic macular telangiectasia type 1 are typically 40 years of age or older. They may have a coincident history of ischemic vascular diseases such as diabetes or hypertension, but these do not appear to be causative factors.
Macular telangiectasia type 2 usually present first between the ages of 50 and 60 years, with a mean age of 55–59 years. They may present with a wide range of visual impact, from totally asymptomatic to substantially impaired; in most cases however, patients retain functional acuity of 20/200 or better. Metamorphopsia may be a subjective complaint. Due to the development of paracentral scotomota (blind spots), reading ability is impaired early in the disease course. It might be even the first symptom of the disease.
The condition may remain stable for extended periods, sometimes interspersed with sudden decreases in vision. Patients’ loss of visual function is disproportionately worse than the impairment of their visual acuity, which is only mildly affected in many cases. In patients with MacTel, as compared with a reference population, there is a significantly higher prevalence of systemic conditions associated with vascular disease, including history of hypertension, history of diabetes, and history of coronary disease. MacTel does not cause total blindness, yet it commonly causes gradual loss of the central vision required for reading and driving.
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 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.
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.
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.
Retinitis is inflammation of the retina in the eye, which can permanently damage the retina and lead to blindness. The retina is the part of your eye that is also known as the "sensing tissue." Retinitis may be caused by a number of different infectious agents. Retinitis, also called Retinitis pigmentosa, has a prevalence of one in every 2,500-7,00 people. This condition is one of the leading causes that leads to blindness in patients in the age range of 20-60 years old.
Retinitis may be caused by several infectious agents, including toxoplasmosis, cytomegalovirus and candida. Cytomegalovirus retinitis is an important cause of blindness in AIDS patients, and is the most common cause of vision loss in AIDS patients. Candida may spread to the retina from the bloodstream, which usually leads to the production of several abscesses in the retina.
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.
RP may be:
(1) Non-syndromic, that is, it occurs alone, without any other clinical findings,
(2) Syndromic, with other neurosensory disorders, developmental abnormalities, or complex clinical findings, or
(3) Secondary to other systemic diseases.
- RP combined with deafness (congenital or progressive) is called Usher syndrome.
- Alport's syndrome is associated with RP and an abnormal glomerular-basement membrane leading nephrotic syndrome and inherited as X-linked dominant.
- RP combined with ophthalmoplegia, dysphagia, ataxia, and cardiac conduction defects is seen in the mitochondrial DNA disorder Kearns-Sayre syndrome (also known as Ragged Red Fiber Myopathy)
- RP combined with retardation, peripheral neuropathy, acanthotic (spiked) RBCs, ataxia, steatorrhea, is absence of VLDL is seen in abetalipoproteinemia.
- RP is seen clinically in association with several other rare genetic disorders (including muscular dystrophy and chronic granulomatous disease) as part of McLeod syndrome. This is an X-linked recessive phenotype characterized by a complete absence of XK cell surface proteins, and therefore markedly reduced expression of all Kell red blood cell antigens. For transfusion purposes these patients are considered completely incompatible with all normal and K0/K0 donors.
- RP associated with hypogonadism, and developmental delay with an autosomal recessive inheritance pattern is seen with Bardet-Biedl syndrome
Other conditions include neurosyphilis, toxoplasmosis and Refsum's disease.
Onset occurs in the first decade, usually between ages 5 and 9. The disorder is progressive. Minute, gray, punctate opacities develop. Corneal sensitivity is usually reduced. Painful attacks with photophobia, foreign body sensations, and recurrent erosions occur in most patients. Macular corneal dystrophy is very common in Iceland and accounts for almost one-third of all corneal grafts performed there.
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).
The most prominent symptoms of Norrie disease are ocular. The first visible finding is leukocoria, a grayish-yellow pupillary reflex that originates from a mass of unorganized tissue behind the lens. This material, which possibly includes an already detached retina, may be confused with a tumor and thus is termed pseudoglioma. However, an affected baby may have a normally sized eye globe and inconspicuous iris, anterior chamber, cornea and intraocular pressure.
Over the first few months of life, complete or partial retinal detachment evolves. From infancy through childhood, the patient may undergo progressive changes in the disease. These progressions include the formation of cataracts, deterioration of the iris with adhesions forming between the iris and the lens or the cornea, and shallowing of the anterior chamber which may increase intraocular pressure, causing eye pain. As the situation worsens, there is corneal opacification, where the cornea becomes opaque, and band keratopathy. Intraocular pressure is lost and the globe shrinks. In the last stage of Norrie disease, the globes appear small and sunken in (phthisis bulbi) and the cornea appears to be milky .
Norrie disease can also have cognitive and behavioral symptoms. Developmental delay or learning difficulties are present in about 30 to 50% of males who have Norrie disease. Psychotic-like features and poorly characterized behavior abnormalities may also be present. Auditory symptoms are common with Norrie disease. Progressive hearing loss starts in early childhood for a majority of males with the condition. Early hearing loss is sensorineural, mild and asymmetric. By adolescence, high-frequency hearing loss begins to appear. Hearing loss is severe, symmetric, and broad-spectrum by the age of 35. However, studies show that while the hearing loss is deteriorating, the ability to speak well is highly preserved. The slowly progressing hearing loss is more problematic to adjust to than the congenital blindness for most people with Norrie disease.
Vitelliform macular dystrophy causes a fatty yellow pigment (lipofuscin) to build up in cells underlying the macula. The retinal pigment epithelium also degenerates. Over time, the abnormal accumulation of this substance can damage the cells that are critical for clear central vision. As a result, people with this disorder often lose their central vision and may experience blurry or distorted vision, and loss is rarely symmetric. Scotomata appear, first with red light and then for green; finally, relative (or in more serious cases, absolute) scotomata occur with white light. Vitelliform macular dystrophy does not affect side (peripheral) vision or the ability to see at night.
Researchers have described two forms of vitelliform macular dystrophy with similar features. The early-onset form (known as Best disease) usually appears in childhood; however, the onset of symptoms and the severity of vision loss vary widely. The adult-onset form begins later, usually in middle age, and tends to cause relatively mild vision loss. The two forms of vitelliform macular dystrophy each have characteristic changes in the macula that can be detected during an eye examination.
Patients with Reis-Bücklers dystrophy develop a reticular pattern of cloudiness in the cornea. This cloudiness, or opacity, usually appears in both eyes (bilaterally) in the upper cornea by 4 or 5 years of age. The opacity elevates the corneal epithelium, eventually leading to corneal erosions that prompt attacks of ocular hyperemia, pain, and photophobia. These recurrent painful corneal epithelial erosions often begin as early as 1 year of age.
With time, the corneal changes progress into opacities in Bowman's membrane, which gradually becomes more irregular and more dense. Significant vision loss may occur. However, vascularization of the cornea is not present.
Reis-Bücklers corneal dystrophy, also known as corneal dystrophy of Bowman layer, type I, is a rare, corneal dystrophy of unknown cause, in which the Bowman's layer of the cornea undergoes disintegration. The disorder is inherited in an autosomal dominant fashion, and is associated with mutations in the gene TGFB1.
Reis-Bücklers dystrophy causes a cloudiness in the corneas of both eyes, which may occur as early as 1 year of age, but usually develops by 4 to 5 years of age. It is usually evident within the first decade of life. This cloudiness, or opacity, causes the corneal epithelium to become elevated, which leads to corneal opacities. The corneal erosions may prompt attacks of redness and swelling in the eye (ocular hyperemia), eye pain, and photophobia. Significant vision loss may occur.
Reis-Bücklers dystrophy is diagnosed by clinical history physical examination of the eye. Labs and imaging studies are not necessary. Treatment may include a complete or partial corneal transplant, or photorefractive keratectomy.