One of the health conditions a cat acquires is strabismus, an abnormal positioning of an animal’s eyeball, thus causing the cat to be “cross-eyed”. In strabismus, one or both eyes can be affected. When both of the cat’s eyes are affected and veer towards the nose, the cat is considered cross-eyed. This is called medial or convergent strabismus and are more common in Siamese Cats. On the other hand, when the eyeballs move away from the nose, this is called divergent strabismus and is more common in Boston Terriers. Both conditions are usually inherited. A normal eyeball placement is usually held in place and can move from side to side and top to bottom with the help of small muscles directly attached to the eyeball. On the contrary, strabismus
The Yorkshire Terrier is described to have personality. He is active, very overprotective, curious, and fond of attention. He is easily trained and learns quickly. He thrives on the love and affection of their owners, which is easily done because of their adorable stature and cute looks. The normal yorkie weighs seven pounds, but the small dog can reach up to fifteen pounds. The yorkie is the seventh most popular dog in America, according to the American Kennel Club, and it only takes one glance at his face and you realize why.
Stone, J. (1972). Morphology and physiology of the geniculocortical synapse in the cat: The question of parallel input to the striate cortex. Investigative Ophthalmology & Visual Science, 11, 338-46.
Pit bulls, the most dangerous dog to ever live. People like to train Pit Bulls to fight other dogs until they are either hurt or dead. The owners that train the dogs are usually the ones that make the dog turn out to be vicious and dangerous. “Each year, 1.2 million dogs are euthanized, approximately 40% of whom are Pit Bulls”(Moore). Pit Bulls don’t know better to understand which is right from wrong since they’re being raised up to fight and protect. Pit Bulls aren’t good family dogs due to the power of their strength and that they could attack at any moment.
Loss of vision in one or both eyes
Some medical professionals do not believe that mental health patients can benefit from therapy dogs and go as far as saying it is a risk far as to say that it is a to the patient and compromise the patients ability to take care of the dog. When people who suffer with mental health issues qualify to get a therapy dog. The mental health patient is tested to see if they are capable of taking care of the dog. Those in need of assistance should use therapy dogs frequently do to the part of the benefits to using these pets to improve mental and emotional health as and physical health. Therapy dogs are beneficial to people who suffer from mental health issues by providing companionship as well as support. Some people with mental health issues have a hard time trusting others and need someone to talk to; Service dogs are important because to make they people with mental health problems feel better and help people with these disorders deal with their emotions.
Clinically referred to as blepharoplasty, eyelid surgery is a cosmetic surgery procedure that involves removal of excess skin, muscle or sometimes fat from the lower and upper eyelids to improve the appearance of the eyelids or correct vision problems related to overhanging eyelids.
Duane Syndrome is an inherited unusual type of strabismus (squint) most often described by the incapability of the eye(s) to move inwards, outwards individually or together. This was first reported via ophthalmologists Jakob Stilling in 1887 and also Siegmund Türk in 1896. The syndrome was named after Alexander Duane, who explained the disorder more specifically in 1905. The syndrome is described as a miswiring of the eye muscles, causing eye muscles to tighten when they don’t need to and other eye muscles not to tighten when they need to. Very often patients get the syndrome by the age of 10 and it is more common in females (60% of the cases) than males (40% of the cases). Although the eye is usually the abnormality associated with Duane Syndrome, there are other bodily functions that can be affected. Duane syndrome cannot be cured, because the cranial nerve is missing and it cannot be replaced. The gene known as “SALL4” has been associated as a cause of this condition.
Heterochromia Iridis is the Greek term for “differently colored irises”. More popularly known as just heterochromia, as the term is described two different-colored eyes that are on the same being. Heterochromia is most commonly found in cats. Instead of calling the condition heterochromia, the term often used for cats is “odd-eyed”. Along with heterochromia, however it has been supposedly known to be linked to other disorders, such as deafness making odd-eyed cats can be more vulnerable to. While heterochromia is usually present when the disorder; deafness is found, heterochromia in cats does not stimulate hearing loss than normally would, because how the mutation develops doesn't contributed to the linked condition, the certain breeds who are more susceptible to heterochromia along with the other associated disorder, and one known condition (hearing loss) linked to cats with heterochromia.
Humans have been studying eye movements for many years now. The first recorded person to publish studies that contributed to the field of eye tracking was Louis Émile Javal [1, 2] in 1878, roughly a century before computers started becoming commonly used. Javal observed human eye movement while reading and was the first to observe that eyes make a combination of rapid movements (which he called saccades) and short stops (which he called fixations). Javal conducted this experiment without the assistance of any instruments, using only his naked eye.
Many signs include a "white pupil," also known as leukocoria. Retinoblastoma can occur in either one or two eyes (Paul T. Finger, Pg. 1). This abnormal white pupillary reflex is sometimes referred to as a cat's eye reflex. Another sign of retinoblastoma is a crossed eye (Ambramson, Ch3). Leukocoria doesn't always end up as being retinoblastoma, it can even result in: congenital cataract, Toxocara canis, Coat's disease, and persistent hypertrophic primary vitreous (PHPV) (Finger, Pg.2). Retinoblastoma occurs when there's a mutation or deletion of the q14 band of chromosome 13 (Finger, Pg. 1). Symptoms can be painful if not treated quickly. Some include a red, painful eye, swelling of the surrounding eye, poor vision, dilated pupil, even extra fingers or toes, and retardation (Ambramson, Ch3).
Hubel DH Wiesel TN. (1970), The period of susceptibility to the physiological effects of unilateral eyeclosure in kittens. J Physiol; 206: 419-36.
Amblyopia is a condition in which visual acuity in one eye is greatly reduced. It is caused by lack of stimulation or disuse during visual development (Rose, 1998). Because the eye is not fully developed at birth (Jarvis, 1992, as cited in Rose, 1998), infants need stimulation to complete the visual neural pathway. When one or both eyes are inhibited, for example due to misalignment of one eye (strabismus) or a large difference in refractive power between two eyes (anisometropia), the neural pathway for the inhibited eye develops abnormally, or does not develop at all. At approximately six years of age eye development is complete (Stager, 1990, as cited in Rose, 1998). Before visual development is complete amblyopia can be treated. If it is caught and treated at an early age, normal vision can be preserved (Rose, 1998).
There are also various eye disorders associated with eyesight such as astigmatism, farsightedness, and nearsightedness. Astigmatism is a condition in which vision at all distances may be blurred or distorted. An irregularly shaped cornea, causing light images to focus on two separate points in the eye, characterizes this condition. When the front of the eye is more oval than round, light does not focus properly on the back of the eye, also known as the retina. Astigmatism is not a disease, but is actually a vision condition that is quite common--only moderate to highly astigmatic eyes need corrective lenses. The signs and symptoms of severe astigmatism are blurred or distorted vision. For mild astigmatism the symptoms are headaches, eyestrain, fatigue, and blurred vision at certain angles. The causes of astigmatism are unclear. It may be genetically inherited or may result from various environmental factors such as poor lighting, incorrect posture, or an increased use of the eyes for close work.
...he cornea is deformed so that its surface is oval instead of spherical. Light rays are distorted at the entrance of the eye. This produces a blurred image and is known as astigmatism. To correct it, glasses are given a nonspherical or cylindrical curvature. Cross-eyes and walleyes are produced when both eyes do not work together because of weakness of the eye muscles.