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Cone dystrophy

A cone dystrophy is an inherited ocular disorder characterized by the loss of cone cells, the photoreceptors responsible from both central and color vision. more...

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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 and have progressive difficulty with daytime vision. 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.

The pathogenesis of cone dystrophy has yet to be elucidated. It appears that the dystrophy is primary, since subjective and objective abnormalities of cone function are found before ophthalmoscopic changes can be seen. However, the retinal pigment epithelium (RPE) rapidly becomes involved, leading to a retinal dystrophy primarily involving the macula. The histological examination of the eyes of one such patient showed that the outer nuclear layer of cones and rods had disappeared completely, whereas the RPE showed pronounced pigment changes. There was also atrophy of the temporal disc.

The fundus exam via ophthalmoscope is essentially normal early on in cone dystrophy, and definite macular changes usually occur well after visual loss. Fluorescein angiography (FA) is a useful adjunct in the workup of someone suspected to have cone dystrophy, as it may detect early changes in the retina that are too subtle to be seen by ophthalmoscope. For example, FA may reveal areas of hyperfluorescence, indicating that the RPE has lost some of its integrity, allowing the underlying fluorescence from the choroid to be more visible. These early changes are usually not detected during the ophthalmoscopic exam.

The most common type of macular lesion seen during ophthalmoscopic examination has a bull’s-eye appearance and consists of a doughnut-like zone of atrophic pigment epithelium surrounding a central darker area. In another, less frequent form of cone dystrophy there is rather diffuse atrophy of the posterior pole with spotty pigment clumping in the macular area. Rarely, atrophy of the choriocapillaris and larger choroidal vessels is seen in patients at an early stage. The inclusion of fluorescein angiography in the workup of these patients is important since it can help detect many of these characteristic ophthalmoscopic features. In addition to the retinal findings, temporal pallor of the optic disc is commonly observed.

As expected, visual field testing in cone dystrophy usually reveals a central scotoma. In cases with the typical bull’s-eye appearance, there is often relative central sparing.

Because of the wide spectrum of fundus changes and the difficulty in making the diagnosis in the early stages, electroretinography (ERG) remains the best test for making the diagnosis. Abnormal cone function on the ERG is indicated by a reduced single-flash and flicker response when the test is carried out in a well-lit room (photopic ERG). The relative sparing of rod function in cone dystrophy is evidenced by a normal scotopic ERG, i.e. when the test is carried out in the dark. In more severe or longer standing cases, the dystrophy involves a greater proportion of rods with resultant subnormal scotopic records. Since cone dystrophy is hereditary and can be asymptomatic early on in the disease process, ERG is an invaluable tool in the early diagnosis of patients with positive family histories.

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Students with Disabilities Discovering Key to Academic Success is an Online Degree; October is National Disability Awareness Month
From Business Wire, 10/7/05

MINNEAPOLIS -- Vida Sanchez grew up in a tropical paradise - but it did not seem that way to her. She remembers squinting a lot as a child. Her mother had to shoo her outside to play. The glorious, sun-drenched days of her island home were something Vida did her best to avoid.

Growing up in the Dominican Republic, Vida had no idea she had a degenerative eye condition called progressive cone dystrophy. She just knew her eyes hurt in the sunlight. And unfortunately, after she came to the United States at the age of 14, her situation did not improve.

But Vida persevered. She wanted to become a teacher, and that is just what she did, earning a teaching degree from Georgetown University with a specialization in languages and linguistics. Over the years, she did her best to manage her condition in the classroom, but by the time she was in her early 40s, her condition had worsened to the point where she was forced to make a difficult decision.

"It just became more and more of an issue and so, by 2001, it was clear I could not function in the classroom anymore. I mean, kids do need light to see what they're doing," she says with a laugh. "And I couldn't work with light."

Not one to let life's adversities dictate her fate, Vida decided to go back to school. She had earned a master's degree in cultural studies from American University in Washington DC, and now she wanted a PhD.

"I always wanted to continue with my education, because I've always seen a natural progression from my preparation as a teacher to going into social services," she says.

But Vida knew her blindness would make attending a traditional university extremely difficult, and she knew she would require some accommodations in order to attend any university. For her disability is as unique as she is, just as every disabled person's situation is distinctly their own.

"My blindness is going to manifest itself differently than someone else's," she explains. "For a blind person that has no sight whatsoever, that person can sit in a classroom and listen. I can't do that. Since light is my problem, sitting in a classroom for an hour or two would be extremely difficult, not to mention painful. I need to be in a dark place."

After much searching for an accredited university with the reputation and academic rigor she demanded, Vida chose to attend Capella University, an accredited online university based out of Minneapolis that serves more than 13,000 students in more than 50 countries. To help ensure her academic success, one of the first things Vida did was contact the university's Disability Services department.

"They make my education possible because of their openness in communicating with me and answering the needs I have. It's that attitude of, "We're here to help you, and whatever that means, we're willing to work it out with you," she says. "It's harder for some people than others. There are a lot of different conditions out there, and they seem to be able to understand that."

After discussing Vida's situation and needs, Capella's Disability Services connected her with resources that could provide her with text books that she could read, a type of CD player that is adapted for the blind called the Victor Reader, and other accommodations to help her successfully complete her PhD. Lisa Bromenshenkel, disability services specialist at Capella, says that Vida's situation is similar to the 350 other students with disabilities at the university: it is unique ... and it can be made to work.

"I have had students who have said that without an online education, they wouldn't have been able to go back to school," she says.

The Capella Web site has been specifically designed to be as accessible as possible for students with a wide variety of disabilities. Both the Web site and learning platform are compatible with popular assistive technology devices such as screen readers, and feature full-text scripts of every audio recording and video offered in the online classrooms. Other examples of accommodations that online universities such as Capella provide to students with disabilities include:

--Additional time on assignments and course room postings

--Advance copies of syllabus/course materials

--Textbooks in audiotape, electronic and Braille format

--Verbal explanations of assignments

--Information on assistive computer software/hardware (such as screen readers for the visually impaired)

--Enlarged-type documents, sign language interpretation, computer-assisted real-time transmission at residential colloquia

For Vida, the combination of a few, reasonable accommodations, as well as the very nature of an online university, has made continuing her education possible. She expects to graduate from Capella with her PhD in 2007, and plans on using her degree to work as a counselor with adolescents and families who are in therapy.

"My disability almost decided for me whether I could actually continue with my education, considering it would be hard to do in a traditional setting," she recalls. "But I was determined to make it work, and I am making it work. I am going to succeed."

About Capella University

Founded in 1993, Capella University is an accredited(a) online university that offers graduate degree programs in business, information technology, education, human services and psychology, as well as a Bachelor of Science online degree program with 10 specializations in business and information technology. The online university currently serves more than 13,000 enrolled learners from all 50 states and 55 countries. Capella University is a wholly-owned subsidiary of Capella Education Company, headquartered in Minneapolis. For more information, visit http://www.capella.edu or call 1-888-CAPELLA (227-3552).

(a) Capella University is accredited by The Higher Learning Commission and a member of the North Central Association of Colleges and Schools, located at 30 N. LaSalle Street, Suite 2400, Chicago, IL 60602-2504, (312) 263-0456, www.ncahigherlearningcommission.org.

COPYRIGHT 2005 Business Wire
COPYRIGHT 2005 Gale Group

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