Hey Folks,
Remember, Dr. Donmoyer is speaking this Friday, September 18th, at noon on her work with vision impairment. Please meet and greet our special guest speaker.
To do the background reading on her topic, go the the seminar schedule for a link to her paper.
If you would like some time to chat with the speaker, please contact Dr. Litowitz. She is handling all the arrangements for Dr. Donmoyer's visit.
Finally, Ludmila is scheduled to being the discussion on her seminar by posting a response question to this message. To see what others did last year, see previous postings by former seminar students.
Looking forward to reading your thoughts in words on this blog!
Dr. Donmoyer gave a very interesting presentation on retinal degeneration of IRBP- deficient mice. We learned that the interphotoreceptor retinoid-binding protein(IRBP) carries Vitamin A needed for vision. Mice that were deficient in IRBP (KO) had fewer photoreceptors (neurons made up of cones and rods needed for phototransduction) compared to wild type mice that were not deficient in IRBP (WT). KO mice also had comparatively strange photoreceptors and overall had less visual function than WT mice.
ReplyDeleteDespite not originally having a research interest in vision and gene expression, her diagnosis of Stargardt eye disease caused an interest in the field. She went on to study gene expression that related to another eye disease, retinitis pigmentosa, causing retinal degeneration in humans and it made me wonder:
What are other types of eye diseases and their causes? These are not limited to humans.
Microphthalmia is a disorder in which one or both eyes are abnormally small. Causes of this condition may include genetic mutations and abnormal chromosomes. Researchers also believe that environmental factors, such as exposure to X-rays, chemicals, drugs, pesticides, toxins, radiation, or viruses, increase the risk of microphthalmia, but research is not conclusive. Sometimes the cause in an individual patient cannot be determined. There is no treatment for severe microphthalmia. However, some less severe forms of microphthalmia may benefit from medical or surgical treatments.
ReplyDeleteLooking back, I wish I had asked Dr. Donmoyer why she chose not to study Stargadt eye disease. I also was amazed to learn at the end of the lecture of how impaired her vision is due to the disease. She is a remarkable individual. In regards to the presentation, she mentioned the possibility of genetically modifying rice so it may be consumed as a source for Vitamin A in parts of the world where Vitamin A deficient diets cause a high prevalence of blindness. I recently read an article describing a method of altering the RNA of crops rather than the DNA, which may achieve greater yield and disease resistance while hopefully being more acceptable to those opposed to genetic modification. Could this method be employed for this purpose perhaps?
ReplyDeleteBenign, pigmented growths, similar to moles on the skin, can occur around the iris of the eye. This is known as a choroidal nevus or more colloquially an eye freckle. On rare occasions nevi may leak fluid or cause abnormal growth of ocular blood vessels, which may lead to retinal detachment, flashing lights, and blindness. Furthermore, nevi have the potential to develop into melanoma similar to that of moles on the skin and tend to grow very rapidly. If you ever wish to see what nevi look like, come gaze into my eyes.
I do remember reading about golden rice which is genetically engineered to contain more beta-carotene genes that produce beta-carotene (precursor to Vitamin A). Scientists have been trying to improve the rice by having it produce enough beta-carotene that would fulfill the required Vitamin A consumption that is needed for those individuals that mainly consume rice and are unable to receive vitamin A from other sources. They call it the Golden Rice Project if you want more information. Also, very interesting about your eyes.
DeleteGlaucoma is group of eye conditions that causes eye nerve damage involving the loss of retinal ganglion cells. The two most common types of glaucoma are primary open angle glaucoma (POAG) and angle closure glaucoma (ACG)
ReplyDeleteThe POAG is mostly painless, slow in development and is asymptomatic until it is significantly progressed. Conversely, the ACG presents with sudden onset of pain, redness of the eye, nausea and vomiting.
Age and genetic predisposition are primarily the risk factors that are linked to the disease onset and progression. The incidences of Primary Open Angle Glaucoma rise with age and its progression is also frequent in people of the African Origin. On the other hand the Angle Closure Glaucoma (ACG) is the common form in the people of Asian origin.
If the disease is diagnosed in its early stages, there may be effective medical and surgical treatment which may help maintain the eye. Otherwise the progression of the condition eventually leads to severe restriction of the visual filed and irreversible blindness.
I thought Friday’s seminar was very interesting, especially considering Dr. Donmoyer has a degree of blindness from Stargardt Disease and is still researching.
ReplyDeleteAnother example of an eye disease is entropion. I chose this condition because I have a Chinese Shar-Pei who had his eyelids tacked back twice due to it. It is a condition which can occur in humans, dogs, and cats. In dogs, breeds with flattened faces or shortened muzzles are more pre-disposed (i.e. English Bulldogs, Mastiffs). Entropion is characterized by the rolling in of the upper and/or lower eyelids onto the eye itself. In turn, since the eyelashes are now scratching the corneal surface, ulceration, scarring, and even blindness can occur if left untreated. Entropion is caused by hereditary factors, such as the facial structuring around the eyes, or by acquired factors, such as weight gain, trauma, or aging. Treatment of entropion in both humans and animals is typically successful and requires a simple surgery of tacking the eyelids or stitching excess skin away from the eyes.
I though that Dr. Donmoyer had very interesting and educational presentation last Friday. I think it's crazy how her disease made her become so involved in learning about vision, and eventually lead to important discoveries. Another eye disease I would like to talk about is Asigmatism. The reason why I chose that condition is because one of my good friends has it, and for a long time he didnt have glasses or contact lenses to help him see better. So every time he would start reading a book or watching TV his eyes would get very tired, and he would eventually just fall asleep. One day he actually decided to see eye doctor and get glasses. His first comment was: I can see the world completely differently, it's like watching a movie in HD quality. I thought that was very exciting. But anyways, back to Astigmatism.
ReplyDeleteAstigmatism is a very common eye condition. A person's eye is naturally shaped like a sphere. Under normal circumstances, when light enters the eye, it refracts, or bends evenly, creating a clear view of the object. However, the eye of a person with astigmatism is shaped more like a football. For this person, when light enters the eye it is refracted more in one direction than the other, allowing only part of the object to be in focus at one time. Objects at any distance can appear blurry and wavy. The specific cause of astigmatism is unknown. It can be hereditary and is usually present from birth. It can change as a child grows and may decrease or worsen over time.
Some ways of treating this condition: eyeglasses, contact lenses, or surgery.
A cataract is a cloudiness on the lenses that affects vision. The lens helps to adjust eye’s focus and see clearly close and far away. As we age, some of the proteins that keep the lens clear clump together and start to cloud in some areas which cause cataract.
ReplyDeleteIn general, cataracts are related to aging. Most of the people will have cataract when they get old. However, there are some types of cataracts which are not related with aging.
1. Secondary cataract: It happens after an eye surgery like glaucoma.
2. Traumatic cataract: It can form after an eye injury which might take years to develop after injury.
3. Congenital cataract: Some infants are born with cataract or develop them later on their childhood.
4. Radiation cataract: it happens after exposure to radiation.
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ReplyDeleteDr. Donmoyer's talk last week was very interesting and it got me thinking about the relationship between liver disease and eyesight. When researching Cirrhosis of the liver, a change in eyesight is never mentioned, however Dr. Donmoyer discussed how the Vitamin A was Stored in the liver and how important Vit A was to the formation of the photoreceptors along with IRBP cells. I think a good follow up study would be to conduct an analysis on rats that had the WT but were severely Vit. A deficient. I am curious to see if there is the same change in size and organization within the photoreceptors. Furthermore I am curious to see if these IRBP cells are most important in development or if they are equally as important in maintenance, for instants what if they were able to knock out the genes for these cells after the photoreceptors have developed? Would they begin to deteriorate?
ReplyDeleteI found it very fascinating that Dr. Donmoyer was able to study a subject field that she had such a strong personal connection too. I think that this would be very difficult to study without always throwing a personal diagnosis into her research. I also wondered why she didn't study the specific disease that she was diagnosed with.
Ocular Albinism: Patients suffering from this condition have reduced pigmentation in the iris and retina. The result is an increased sensitivity to light and severely impaired visual acuity. Pigmentation in the retina allows the eye to properly process the incoming light and form the electrical signals that are sent to the brain. Without the proper pigmentation levels, the retina is unable to filter out excess light and effectively interpret the incoming light for signaling. The iris’ main function is to regulate the levels of light entering the eye. Without proper pigmentation, the iris will let more light into the eye resulting in the increased sensitivity. Impaired depth perception and nystagmus (involuntary eye movements) are other common symptoms with Ocular Albinism. This disease has genetic basis and is the result of mutations in a gene that codes a vital melanosome protein. Without this vital protein, the melanosomes are unable to properly regulate growth and store melanin. Since this is developmental issue and not all of the genetic components have been identified, there is a large range of severity in the condition among individuals. Some patients have little impairment and are able to perform vision related tasks like driving. Others, can have an almost complete loss of vision and must learn Braille to perform tasks like reading.
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ReplyDeletePresbyopia is a common type of vision disorder that occurs as you age. It is often referred to as the aging eye condition. Presbyopia results in the inability to focus up close, a problem associated with refraction in the eye. There are several types of refractive disorders namely myopia and astigmatism. It is possible to suffer from a different disease in each eye.Presbyopia happens naturally in people as they age. The eye is not able to focus light directly on to the retina due to the hardening of the natural lens. Aging also affects muscle fibers around the lens making it harder for the eye to focus on up close objects. The ineffective lens causes light to focus behind the retina, causing poor vision for objects that are up close.When you are younger, the lens of the eye is soft and flexible, allowing the tiny muscles inside the eye to easily reshape the lens to focus on close and distant objects.
ReplyDeleteSymptoms include a hard time reading small print, headaches and holding reading material further away from you to focus. A comprehensive eye dilation exam is normally what is used to diagnose presbyopia.
Treatment involves eyeglasses to help refract light. Research on techniques to insert new lenses are being investigated and may be a way to figet this disease in the future.