$Unique_ID{BRK04182} $Pretitle{} $Title{Retinoschisis} $Subject{Retinoschisis Congenital Retinal Cyst Congenital Vascular Veils in the Retina Giant Cyst of the Retina Vitreoretinal Dystrophy Retinoschisis, Typical (Blessig Cysts; Iwanoff Cysts; Peripheral Cystoid Degeneration of the Retina) Retinoschisis, Juvenile (Familial Foveal Retinoschisis; Congenital Retinoschisis) Retinoschisis, Senile Macular Degeneration } $Volume{} $Log{} Copyright (C) 1988, 1989 National Organization for Rare Disorders, Inc. 517: Retinoschisis ** IMPORTANT ** It is possible the main title of the article (Retinoschisis) is not the name you expected. Please check the SYNONYMS listing on the next page to find alternate names and disorder subdivisions covered by this article. Synonyms Congenital Retinal Cyst Congenital Vascular Veils in the Retina Giant Cyst of the Retina Vitreoretinal Dystrophy DISORDER SUBDIVISIONS: Retinoschisis, Typical (Blessig Cysts; Iwanoff Cysts; Peripheral Cystoid Degeneration of the Retina) Retinoschisis, Juvenile (Familial Foveal Retinoschisis; Congenital Retinoschisis) Retinoschisis, Senile Information on the following disease may be found in the Related Disorders section of this report: Macular Degeneration General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Retinoschisis means splitting of the eye's retina into two layers. The various forms of this disorder can be inherited or acquired. The disorder is characterized by a slow progressive loss of parts of the field of vision corresponding to the areas of the retina which have become split. Often, Retinoschisis is associated with the development of saclike blisters (cysts) in the retina. Symptoms Retinoschisis is characterized by splitting of the eye's retina into two layers, accompanied by the formation of cysts. The disorder occurs in the following forms: Typical Retinoschisis: This form of the disorder usually occurs among males who are farsighted (hyperopic). Frequently, splitting of the retina occurs in both eyes symmetrically. Splitting may begin in the lower or upper quarter of the retina located toward the temples. Vision is impaired correspondingly. To an ophthalmologist looking into the eye with an ophthalmoscope, the lesion appears as a thin, transparent, veil-like membrane extending up as a dome into the glass-like inside of the eyeball (vitreous). This membrane contains the blood vessels of the retina and often has small white dots (opacities). Defective vision in bright light (hemeralopia) may also occur. The progression of splitting and vision loss often stops for many years. However, in some cases the progression may occur faster. Senile Retinoschisis: This form of the disorder is similar to Typical Retinoschisis but it usually occurs in older patients, often without apparent symptoms. Both eyes are affected in 90% of cases. Symptoms may develop because of the flowing together (coalescence) of peripheral sacs (Blessig Cysts; Iwanoff Cysts). In the early stage, the cystic space is spanned by thin grey fibers which gradually break. This allows the inner and outer leaves of the retina to separate, forming an elevated cyst. In Senile Retinoschisis, the split may extend all the way around the edge of the retina. However, it does not usually progress to the back of the retina and may remain unchanged for many years. Juvenile Retinoschisis: This form of the disorder is the most serious type of Retinoschisis. It is a slowly progressive genetic disorder occurring among young males. Splitting of the retina often extends back over the area near the center of the visual field (macula). Retinoschisis may affect the center of the macula (called the "fovea"), which is the area of clearest vision. In the early stages, the areas of the retina that are splitting often exhibit large holes in the anterior leaf between blood vessels, and if breaks develop in both the front and the back layer of the retina, a true retinal detachment may occur causing loss of parts of the field of vision. A completely blind area (scotoma) with a sharp edge in the area where splitting (schisis) occurs is evident in the patient's visual field. The recording of electric impulses from the eye's retina (electroretinogram; or ERG) shows waves which are markedly lower than normal, but not obliterated. Patients with Juvenile Retinoschisis often have cystic macular degeneration which causes additional loss of vision. Causes Typical Retinoschisis is usually an autosomal dominant genetic disorder. Senile Retinoschisis is usually an autosomal recessive genetic disorder. Juvenile Retinoschisis is a sex-linked hereditary disorder. Acquired cases of Retinoschisis occur with aging for unknown reasons. Human traits including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed "dominating" the normal gene and resulting in appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child. In recessive disorders, the condition does not appear unless a person inherits the same defective gene from each parent. If one receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will show no symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is twenty-five percent. Fifty percent of their children will be carriers, but healthy as described above. Twenty-five percent of their children will receive both normal genes, one from each parent and will be genetically normal. X-linked recessive disorders are conditions which are coded on the X chromosome. Females have two X chromosomes, but males have one X chromosome and one Y chromosome. Therefore in females, disease traits on the X chromosome can be masked by the normal gene on the other X chromosome. Since males have only one X chromosome, if they inherit a gene for a disease present on the X, it will be expressed. Men with X-linked disorders transmit the gene to all their daughters, who are carriers, but never to their sons. Women who are carriers of an X-linked disorder have a fifty percent risk of transmitting the carrier condition to their daughters, and a fifty percent risk of transmitting the disease to their sons. Affected Population Typical Retinoschisis usually occurs in young males who are farsighted. Senile Retinoschisis usually affects persons in their 50's, 60's or 70's. It affects males and females in equal numbers. Juvenile Retinoschisis is a rare disorder, affecting only boys. However, there are very rare exceptions which occur when a girl is born to a mother who is a carrier of the disorder and an affected father. This form of the disorder is present at birth, and symptoms progress with time. Related Disorders Symptoms of the following disorder may be similar to those of Juvenile Retinoschisis. Comparisons may be useful for a differential diagnosis: Macular Degeneration is a common hereditary disorder of the eye's retina characterized by a gradual bilateral decrease of vision. Macular degeneration can be a static condition for many years but then it becomes slowly progressive. An area of impaired vision (central scotoma) within the visual field, surrounded by a peripheral area of normal vision, is also symptomatic of this disorder. A vision disturbance in which shapes seem distorted or changing (metamorphopsia) can also occur. (For more information on this disorder, choose "Macular Degeneration" as your search term in the Rare Disease Database.) Therapies: Standard Diagnosis of Retinoschisis can be made through various tests: Measuring visual acuity with the Snellen chart, the patient is asked to look through a pinhole to determine where on the retina a lesion may exist. Ultrasonography or ultrasound may show abnormalities when a hemorrhage has occurred in the eye. A recording of the electrical impulses emitted by the retina in response to light stimulus (electroretinogram; ERG) can be made. These ERG's can indicate abnormalities of the retina. A Visual Evoked Response (VER) measures slow electric potentials from the brain cortex in response to light stimulation. The VER depends on the integrity of the entire visual system from the cornea to the occipital part of the brain's cortex. The VER is a good objective test to detect the function of the macular portion of the retina which controls central vision. Electro-oculography (EOG) is another electrophysiological test to determine the function of the retina, mainly the nerve cells that respond to light stimuli (receptors). A photographic picture made with an ophthalmoscope of the back portion of the inside of the eyeball (fundus) is another way to gather information about the retina. When a child cannot tolerate the dilation of the eye's pupil and the bright light used for some of these tests, general anesthesia may be necessary. Typical and Senile Retinoschisis usually do not require medical treatment. In children with Juvenile Retinoschisis, when bleeding occurs within the eyeball, keeping the eye still helps to settle the blood. Later, treatment with laser or cold (cryotherapy) can be applied to close off the damaged area of the retina. It is imperative to avoid jarring the head or inflicting injury to the eye to slow down the degenerative process of Juvenile Retinoschisis. With treatment, the person with Juvenile Retinoschisis usually retains functional vision. Genetic counseling is recommended for families of children with Juvenile Retinoschisis. Therapies: Investigational This disease entry is based upon medical information available through June 1988. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Retinoschisis, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 The Association for Macular Diseases 210 East 64th Street New York, NY 10021 (212) 605-3719 NIH/National Eye Institute 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5248 National Association for the Parents of the Visually Impaired, Inc. (NAPVI) P.O. Box 180806 Austin, TX 78718 (512) 459-6651 National Association for the Visually Handicapped 305 East 24th Street New York, NY 10010 (212) 889-3141 Eye Research Institute of Retina Foundation 20 Staniford Street Boston, MA 20114 (617) 742-3140 Retinitis Pigmentosa Foundation Fighting Blindness 1401 Mt. Royal Avenue, 4th Floor Baltimore, MD 21217 (301) 225-9400 (800) 638-2300 Vision Foundation, Inc. 818 Mt. Auburn Street Watertown, MA 02172 (617) 926-4232 (800) 852-3029 (within MA) American Foundation for the Blind (AFB) 15 W. 16th St. New York, NY 10011 (212) 620-2000 Regional offices: Atlanta, GA (404) 525-2303 Chicago, IL (312) 245-9961 Dallas, TX (214) 352-7222 San Francisco, CA (415) 392-4845 American Council of the Blind, Inc. (ACB) 1155 - 15th St., NW, Suite 720 Washington, D.C. 20005 (202) 467-5081 (800) 424-8666 For genetic information and genetic counseling referrals, please contact: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 References MENDELIAN INHERITANCE IN MAN, 7th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 1236-1237. DEGENERATIVE RETINOSCHISIS WITH GIANT OUTER LAYER BREAKS AND RETINAL DETACHMENT: J.M. Sulonen, et al.; American Journal Ophthalmol (February 15, 1985: issue 99(2)). Pp. 114-121. INDICATIONS FOR VITRECTOMY IN CONGENITAL RETINOSCHISIS: J. Schulman, et al.; British Journal Ophthalmol (July 1985: issue 69(7)). Pp. 482-486. X-LINKED RETINOSCHISIS IS CLOSELY LINKED TO DXS41 AND DXS16 BUT NOT DXS85: T. Alitalo, et al.; Clin Genet (September 1987: issue 32(3)). Pp. 192-195. VASCULARIZED VITREOUS MEMBRANES IN CONGENITAL RETINOSCHISIS: D.F. Arkfeld, et al.; Retina (Spring 1987: issue 7(1)). Pp. 20-23.