“I’m not touching that!” CTEBVI 52 March 17, 2012 Rosa Tu Bianca Ciebrant Rosalinda Mendiola

Lens The part of the eye immediately behind the iris that performs delicate focusing of light rays upon the retina. In persons under 40, the lens is soft and pliable, allowing for fine focusing from a wide variety of distances. For individuals over 40, the lens begins to become less pliable, making focusing upon objects near to the eye more difficult. This is known as presbyopia. Source: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/lens

Congenital Cataracts Cataracts are cloudy areas in the lens inside the eye - which is normally clear. Cataracts can develop in one or both eyes. If they develop in both eyes, one will be more severely affected than the other. A normally clear lens allows light to pass through to the back of the eye, so that the patient can see well-defined images. If a part of the lens becomes opaque light does not pass through easily and the patient's vision becomes blurry - like looking through cloudy water or a fogged-up window. Source: http://eyeinstitutenc.com/cataract/

Retina The membrane lining the back of the eye that contains photoreceptor cells. These photoreceptor nerve cells react to the presence and intensity of light by sending an impulse to the brain via the optic nerve. In the brain, the multitude of nerve impulses received from the photoreceptor cells in the retina are assimilated into an image. Source: http://webvision.med.utah.edu/book/part-i-foundations/simple-anatomy-of-the-retina/

Hemianopsia Hemianopia, also known as Hemianopsia, is loss of vision in either the right or left sides of both eyes; a common side effect of stroke or brain injury.  This vision loss causes serious problems with mobility, bumping into objects, increased incidence of falls and accidents and reading problems. Source: http://medical-dictionary.thefreedictionary.com/hemianopsia

Hemianopsia

Optic Nerve The optic nerve is the structure which takes the information from the retina as electrical signals and delivers it to the brain where this information is interpreted as a visual image. The optic nerve consists of a bundle of about one million nerve fibers. Source: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/opticnerve.html#c3

Glaucoma Glaucoma is a disease of the major nerve of vision, called the optic nerve. The optic nerve receives light-generated nerve impulses from the retina and transmits these to the brain, where we recognize those electrical signals as vision. Glaucoma is characterized by a particular pattern of progressive damage to the optic nerve that generally begins with a subtle loss of side vision (peripheral vision). If glaucoma is not diagnosed and treated, it can progress to blindness. Source: http://www.visionsimulations.com/index.glaucoma

Retinal Detachment When a portion of the retina is detached it is no longer in communication with the brain, resulting in areas of blankness. Spatial distortions may exist at the margin of the detachment. Floaters is one of the symptoms of a retinal detachment. Source: http://www.webmd.com/eye-health/detached-retina

Retinal Detachment

Total Blindness Blindness is the condition of lacking visual perception due to physiological or neurological factors. Various scales have been developed to describe the extent of vision loss and define blindness. Total blindness is the complete lack of form and visual light perception and is clinically recorded as NLP, an abbreviation for "no light perception." Blind people with undamaged eyes may still register light non-visually for the purpose of circadian entrainment to the 24-hour light/dark cycle. Light signals for this purpose travel through the retinohypothalamic tract and are not affected by optic nerve damage beyond where the retinohypothalamic tract exits Source: http://en.wikipedia.org/wiki/Blindness

Total Blindness

We see with our brains, not with our eyes Source: http://vnl.cps.utexas.edu/images/occipital.jpg

Related Eye Conditions Amblyopia also known as lazy eye. Aphakia when the lens of the eye has been removed. Nystagmus is the involuntary movements of the eyes. Photophobia is the sensitivity to light. Strabismus the turning in of the eyes.

Related Eye Conditions

VISION SIMULATORS

The Importance of Early Intervention

A special thank you to the families who gave us permission to share photos and stories of their children…our “teachers.”

Resources Blind Childrens Center www.blindchildrenscenter.org Blind Babies Foundation Pediatric Visual Diagnosis Fact Sheets www.blindbabies.org

References Blind Babies Foundation. (2010, 2011). Retrieved from www.blindbabies.org Blind Childrens Center. (2012). Retrieved from www.blindchildrenscenter.org Eye Institute of NC PC. Cataract [Image], Retrieved 10 March 2012, from: http://eyeinstitutenc.com/cataract/ HyperPhysica. Lens [Image], Retrieved 12 March 2012, from: http://www.hyperphysics.phy-astr.edu/hbase/vision/ eyescal Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. (2003) by Saunders, an imprint of Elsevier, Inc. Hemianopia [Image], Retrieved 10 March 2012, from: http://medical-dictionary.thefreedictionary.com/hemianopsia

References Nucleus Communications, Inc. (2001, 2003). Detached Retina [Image], Retrieved 10 March 2012, from: http://www.webmd. com/eye-health/detached-retina as cited on http://www. nucleusinc.com Vision Simulations. Glaucoma [Image], Retrieved 12 March 2012, from: http://www.visionsimulations.com/index.glaucoma Visual Neuroscience Lab. Occipital lobe [Image], Retrieved 12 March 2012, from: http://vnl.cps.utexas.edu/images/ occipital.jpg Webvision. retina [Image], Retrieved 12 March 2012, from: http://webvision.med.utah.edu/book-i-foundations/simple- anatomy-of-the-retina/ Wikipedia. Blindness [Image], Retrieved 12 March 2012, from: http://en.wikipedia.org/Blindness/