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Eye Sight

Human Eye vs Eagle Eye

Eagles are beautiful birds known for their majestic frame and incredible hunting abilities. They have the reputation of having one of the best visions on the planet. What makes ‘eagle eyes’ a thing of envy? Let’s find out.

What is Visual Acuity?

Visual acuity is the eye’s ability to separate details of an object without any blur. The normal or a ‘good’ vision for a human is 20/20. Eagles, however, have retinas with cones and have a much deeper fovea—a cone-rich structure in the back of the eye. These give them a visual acuity of an impressive 20/5, or 20/4 which allows them to hunt even the tiny prey from hundreds of feet up in the air.

How Is the Eagle’s Vision Measured?

There is a scientific set-up to determine the strength of eagle’s vision. The birds are trained to fly down a long tunnel where two TV screens are kept at the end. One screen has a display of striped pattern to attract the eagle towards it and when they land on that screen, they are given a treat. The birds’ acuity is tested by changing the width of the stripes and determining from what distance the eagles begin to turn in the correct direction.

The Range and Vividness of Colors

Eagles have the ability to see colors more vividly than humans can. They can even see ultraviolet light and pick out more shades of one color. Their ability to even see the UV light allows them to see the bodily traces left by their prey. Mice’s and other small prey’s urine is visible to the eagles in the ultraviolent range, making them easy targets even a few hundred feet above the ground.

Positioning of the Eyes

Human eyes are positioned at the front of the heads, giving us a binocular vision and a peripheral vision of just 180 degrees. We can only see complete images when we use both eyes, as closing one will block a portion of vision that was visible with that eye. The use of both eyes gives us that ability to determine the depth of field and help us realize the speed of any moving object. Unfortunately, our peripheral vision is quite poor.

On the other hand, an eagle’s eyes are rotated towards the front of the head and are angled 30 degrees from the midline of the face. This allows them to have a 340 degree field of vision. Their peripheral vision is quite impressive, which greatly assists these predatory birds.

Ability to Focus Clearly

The ability to switch between seeing things that are near and far clearly require quick changes in the lens of the eyes, which is known as accommodation. As humans age, the muscles required to change the shape of the lens get stiff and become less effective, requiring us to wear glasses to see distant and nearby things equally clear. However, the eagles not only have a lens that changes the shape to accommodate the changing distance but even their cornea has the ability to change shape to better focus on near and far objects.

Can We Get Eagle Eyes?

It is obvious to want vision like an eagle but the characteristics and dimensions of human eye’s lens, cornea, iris, retina etc. limits our visual acuity. The best vision we can achieve is 20/10 or even 20/8. LASIK can help you in getting 20/20 vision even if you have poor vision, but achieving the visual acuity of an eagle is next to impossible.

While attaining eagle eyes will remain a fantasy for us, you can improve your eye sight through LASIK. Visit InSight Vision Center and make an appointment today to explore your options.

Prevent AMD with right nutrition

Age-Related Macular Disease or AMD is an acquired ocular disorder that occurs in people over sixty years of age. It is the leading cause of vision loss in the US. This eye disease affects the central part of retina known as the macula and destroys it through retinal detachment. Macula is responsible for providing sharp and clear central vision that is required for reading, writing and other visually demanding activities such as driving, stitching etc. The risk of AMD increases with age.

The severity and nature of AMD differs from one person to the other. Many experience some or full degree of loss of central vision in one or both the eyes. As AMD progresses, it diminishes the ability of the individual to read, write, walk or drive safely, even recognize faces and perform everyday tasks. Around 90% of AMD patients have a non-exudative or dry form of the disease that results in the development of dry, atrophic scars in the macular area. These patients experience slower, more gradual loss of vision. The other 10% develop an exudative or wet form – this results in the leaking of fluid beneath the retina, with a greater and more rapid loss of central vision.

Apart from aging, other risk factors include family history, poor diet, cardiovascular disease, obesity, lack of physical exercise, smoking, and high blood pressure.

How Can You Prevent AMD through Nutrition

There are studies that prove that diet, not just supplements, can greatly help in preventing AMD. Diets with above-median levels of beta-carotene, which includes lutein and zeaxanthin, vitamins C and E, and zinc have been associated with a 35% reduced risk for the disease. Additionally, food sources that are rich in omega-3 fatty acids are also highly effective. Incorporating plenty of green leafy vegetables along with fish is highly recommended to prevent AMD.

Let us look at some food sources to obtain the necessary nutrients:

  • Veggies and fruits with carotenoids (beta-carotene, lutein, zeaxanthin) and vitamin C: Broccoli, peaches, kale, apricots, pumpkin, carrots, mangoes, bell peppers, tangerines, cantaloupe, avocado, spinach, grapefruit, blueberries, green peas, honeydew, collards.
  • Foods high in vitamin E: Tofu, almonds, sunflower seed kernels, fortified soymilk, peanuts, turnip greens, canned tomato products, wheat-germ oil, sunflower oil, fortified cereals
  • Foods that provide zinc: Whole-wheat and buckwheat flours, lamb, fortified cereal, dark meat poultry, Alaskan king crab, pork, pumpkin seeds, lean beef, dried beans, bulgur
  • Fish high in omega-3 fatty acids: Salmon, albacore tuna, mackerel, sardines, lake trout, herring

Decelerating the Progression of AMD

Though most dietary supplements cannot completely prevent AMD, they can definitely slow down its progression in those who are already suffering from the disease. High levels of vitamins C and E, beta-carotene, zinc and copper from supplements are known to reduce the risk of progression to advanced AMD by 25% after 5 years. The effect persisted for another 5 years of follow-up after the study.

Things to Do

Follow a diet that provides carotenoids such as beta-carotene, lutein and zeaxanthin, vitamins C and E, zinc and omega-3 fatty acids. Not only will it boost your health but also help in preventing AMD. If you have a family history of AMD, consult with your doctors regarding the supplements you need. Make necessary lifestyle changes – quit smoking, exercise regularly, keep your blood pressure and cholesterol levels at acceptable levels.

If anyone over the age 60 in your family is suffering from vision problems, get it checked immediately at InSight Vision Center. Make sure they follow the right diet and ea nutritious food to prevent AMD or reduce the speed of its progression.

vision problems in kids

A healthy vision is essential for the development of every child. A weak vision or eye problems will affect a child’s learning ability and personality, in addition to affecting his/her school work. The next time you take your child for a health check-up, make sure you include eye tests too.

Eye Specialists to Visit

Make an appointment with either of the following, depending on the vision test and care required:

  • Ophthalmologist: They treat eye problems and are qualified to perform eye surgeries.
  • Optometrist: Similar to ophthalmologists, except that they do not perform surgery.
  • Optician: They can give routine eye-exams to test vision and can fit/adjust eyeglasses to rectify vision problems.

Uncommon Warning Signs

Not all vision problems start with blurry vision or inability to see things clearly. Some symptoms can go unnoticed, such as:

  • Wandering or crossed eye: It affects 3-5% of children. Its symptoms include an eye that drifts or appears crossed in respect to the other eye.
  • Uneven focus: It occurs when one eye is more farsighted than the other. This affects 2-3% of kids. Detecting this problem can be tricky as younger children may not realize that their vision is compromised.

These problems occur in kids between the ages of 18 months and 4 years.

Vision Screening and Treatment

Doctors recommend that the first full vision screening should be done by the age of 3. Follow it with an in-depth examination to detect the underlying problem. The treatment for most eye problems is done with eye-drops, eye patches, glasses or special lenses. Surgery might be recommended if the patches, drops or lenses don’t work to correct the problem.

Detecting Eye and Vision Problems in Children

Vision problems can be detected through the following warning signs:

  • Eye rubbing and redness of eye
  • Tearing and swelling
  • Droopy eyelids
  • Pus or crust
  • White, yellow, or gray-white material in the pupil
  • Sensitivity to light
  • Rush to an eye doctor the moment you see these symptoms.

Common Eye Problems in Children

Amblyopia: Also known as ‘lazy eye’, amblyopia is poor vision in an eye that appears to be normal. Crossed eyes and different refractive error between both eyes cause amblyopia. It should ideally be treated before the age of 8, after which it can cause irreversible visual loss in the affected eye.

Strabismus: This is caused due a misalignment of the eyes, i.e., when they may turn in, out, up or down. A chronically misaligned may also lead to amblyopia. If detected early, the vision can be restored by patching the properly aligned eye, forcing the misaligned eye to work. It can be corrected through surgery or specially designed glasses too.

Refractive errors: When the shape of the eye doesn’t refract the light properly, images will appear blurred. Refractive errors can also cause amblyopia. Common refractive errors include:

  • Nearsightedness: Also called myopia, nearsightedness is poor distance vision when you can’t see things that are at a distance.
  • Farsightedness: When you have trouble seeing close objects, it’s called farsightedness or hyperopia.
  • Astigmatism: This causes an imperfect curvature of the front surface of the eye, which makes the objects appear either ‘stretched’ or ‘shrunk’.

All refractive errors can be treated with eye-glasses, contact lenses or surgery.

Depending on the severity of the condition, vision treatments like patching may last for couple of weeks, months to about a year. Use of glasses or contact lenses may be more permanent. Get your child’s vision tested today to assure healthy eyes. Do not ignore the warning signs or delay the treatment as it can cause permanent vision loss in the affected eye.

InSight Vision Center offers precise treatments for all types of eye problems. Schedule a consultation today and know the best treatment options for your child.

Color Blindness

Color vision deficiency, or color blindness, is the inability to distinguish certain shades of colors. In highly severe cases, people can’t see the concerned colors at all though very few people are completely color blind (who can see things only as black, white and shades of gray). Color blindness occurs when there is a damage or loss of ‘cones’, which are the photoreceptors in the retina making color vision possible. If the cones lack one or more light sensitive pigments, there will be a deficiency in the color perception, making it difficult to see one or more of the three primary colors.

Types of Color Vision Deficiencies

  • The Red-Green Color Deficiencies
    The most common color vision deficiency, this affects more men than women. People have difficulty in distinguishing between different shades of red, green and yellow. Either they all appear to be a similar color, appear dull or can only be distinguished by slightly different brightness and intensity. They may even confuse red with black. Shades of purple will appear blue as you won’t be able to see the red component in them.
  • Deuteranopia And Deuteranomaly
    This occurs when there is a loss of M-cones. It’s a less severe form of red-green color vision deficiency where you’ll have trouble differentiating between different shades of the same color in the red-yellow-green spectrum.
  • Protanopia And Protanomaly
    Loss of L-cones leads to protanopia. You’ll confuse colors in the red-yellow-green spectrum if you suffer from this deficiency. Protanomaly is a less severe form where you won’t be able to distinguish different shades of the same color in the red-yellow-green spectrum. Those suffering from either disease are likely to see red colors as darker than normal.
  • Blue-yellow color vision deficiency
    This deficiency is quite rare and is caused due to a deficiency of S-cones. It’s also known as Tritanomaly or Tritanopia. With this deficiency you will have difficulty distinguishing between blue and green, with green appearing as a shade of blue. Some even see yellow as a pale shade of grey or purple.

color deficiency test

Symptoms and Signs to Look Out For

Common symptoms to identify color blindness include:

  • Inability to distinguish between colors
  • Difficulty in differentiating or seeing tones and shades of the same color
  • Rapid eye movement in very rare cases

Causes of Color Vision Deficiency

Most cases of color deficiency are genetic and are passed from the parents to kids. Apart from that, certain diseases and medical conditions may also lead to a loss in color recognition. Some include:

  • Diabetes
  • Glaucoma
  • Macular degeneration
  • Alzheimer’s disease
  • Leukemia
  • Sickle cell anemia

Other factors also include:

Medication: Drugs used for treating nervous disorders, heart problems, high blood pressure and psychological problems can affect color vision.

Chemical Exposure: Prolonged exposure to some fertilizers and chemicals has caused loss of color vision in some individuals.

Aging: As a person ages, his/her ability to see and recognize colors diminishes.

Treating Color Blindness

In most cases there is no cure, but if it’s caused due to an illness or an eye-injury, treatment may improve the color vision. Color cues and other methods can help color-deficient people to compensate for their inability to distinguish colors.

  • Organizing and labeling your furniture, clothes and other colored objects will help in easy recognition.
  • Some objects such as traffic signals have a fixed order of colors. Remembering such order of things rather than focusing on the color will help in identifying colors correctly.

If you suspect colorblindness in yourself or a loved one, go to an eye doctor immediately. Give InSight Vision Center a call and make an appointment today for a comprehensive diagnosis.

Refractive Eye Error

When the shape of the eye prevents the light rays from focusing directly on the retina, and rather focuses in the front or back of the retina, refractive error occurs. Factors such as length of the eyeball, aging of the lens and change in the shape of the cornea contribute to refractive errors.

What is Refraction

The phenomenon of bending of light when it passes from one object to another is called refraction. Light rays bend when they pass through cornea and lens, enabling one to see objects. Optical refractive index refers to the number that measures how much light gets refracted in the eye, which gives an idea if you are suffering from a refractive error or not.

Types of Refractive Errors

  • Myopia
    Also known as nearsightedness, it occurs when the eyeball is too long for the refractive power of the cornea and lens. Due to the long size, the light gets focused in front of the retina rather than directly on it. The person suffering from myopia has trouble seeing the distant objects clearly.
  • Hyperopia
    This is a common refractive error where people have trouble seeing near objects as compared to faraway objects. It’s also known as farsightedness and this occurs when the eyeball is too short for the refractive power of the cornea and lens. This causes the light to focus behind the retina, which makes it difficult to focus clearly on objects that are near.
  • Astigmatism
    When the cornea or lens isn’t perfectly round or spherical, astigmatism occurs. In this condition the eye cannot focus the light evenly onto the retina, which causes objects to appear stretched out and blurred at any distance.
  • Presbyopia
    This is an age-related condition where one loses the ability to focus on anything up close. When people turn 40 years and above, the lens becomes stiff and can’t change its shape easily. This doesn’t allow the eye to focus on close objects clearly.

What Causes Refractive Errors?

  • Genetics: Children whose parents suffer from certain refractive errors are more likely to develop refractive errors themselves.
  • Environmental: Factors like age and health issues can greatly affect the health of the eye and cause refractive errors.

Signs and Symptoms of Refractive Errors

The most common symptom of refractive error is blurred vision. Others include:

  • Double vision
  • Halos around bright lights
  • Haziness
  • Headaches and eye strain
  • Red, itchy and dry eyes
  • Constant watering of eyes

Treatment for Refractive Errors

  • Eyeglasses
    The most common treatment of refractive errors consists of eye-glasses. Based on the degree of error, doctors prescribe appropriate lenses to correct it and give you clear optimal vision.
  • Contact Lenses
    Made of plastic, they provide clearer and a wider field of vision. They act as the first refractive surface for the light rays entering the eyes and causes precise focus or refraction. They offer great comfort too. However, it is crucial to wash your hands and clean the lenses before putting them on to reduce the risk of infection. Discuss with your doctor if your eye condition supports the use of contact lenses.
  • Refractive Surgery
    This surgery changes the shape of the cornea permanently. By doing so, the focusing power of the eye is restored as it allows the light rays to focus precisely on the retina for improved vision. Before opting for refractive surgery, consult with your doctor if this is the right treatment for you.

    Do not take blurred vision and watery eyes for granted. These may be symptoms of underlying refractive errors. Get an accurate diagnosis at Insight Vision Center and have it rectified at the earliest to keep complications at bay.

Eye injuries

People in certain professions are at a constant risk of an eye-injury. However, while their chances of hurting their eyes are higher than others, almost everyone else is also equally prone to an eye injury. Accidents around the house such as a flying objects or hitting the head against something can hurt your eye. Thankfully, you can prevent most eye-injuries or further aggravate an injury by taking a few precautions.

Simple Tips to Prevent an Eye Injury

The following tips will immensely help in preventing eye injuries on different occasions:

  • Using Protective Eye-Wear During Outdoor Activities And Sports
    Safety glasses and goggles are a must when your work exposes you to dust or flying particles. Activities such as welding, metal grinding etc. require protective eye gear. Use the right protective eye wear while playing sports such as tennis, swimming etc. too.
  • Being Extra Careful While Using Chemicals And Cleaners
    Read instructions carefully before using chemicals and cleaning supplies such as bleach, pesticide spray etc. Keep them away from the reach of children.
  • Supervise Your Child’s Use Of Sharp Tools And Objects
    Household items such as knives, scissors, forks, wire hangers, paper clips, fishhooks and even rubber bands can cause serious damage to the eye. Supervise kids when they are using these items and keep them away from their reach when not in use.
  • Don’t Buy Certain Children’s Toys
    Keep projectile toys such as darts, missile-firing toys away from children. Don’t allow them to play with non-powder rifles such as pellet guns and BB guns as well.
  • Avoid The Use Of Laser Pointers
    Laser pointers can permanently damage the retina when directly exposed to the eye. Partial vision loss is also possible. Don’t point the beam toward anyone’s eyes directly.
  • Exercise Caution While Cooking Or Using Hot Objects
    Splattering oil or high flames in kitchen can be dangerous. Use grease shields to keep the eyes safe. Avoid using a curling iron or hair-straightener near your eyes.
  • Eliminate Hazards Caused By Sharp Objects
    Cover sharp edges and corners of furniture with padded materials. Secure the railings and pointed objects too.
  • Leave Fireworks To Professionals
    Do not handle fireworks by yourselves and don’t let kids use them. If you want to indulge in fireworks for any occasion, call the professionals.
  • Open A Champagne Bottle With Extreme Caution
    Point the bottle away from yourself and bystanders. Place your palm over the while removing the wire hood and grasp the cork tightly until it comes out of the neck instead of letting it pop and fly.
  • Car Safety Measures
    Secure your child in a car-seat and seat belt. Keep loose and sharp objects in the truck.

Signs and Symptoms of an Eye Injury

  • Immense pain in the eye
  • Unusual pupil shape or size
  • Blood in the eye
  • Prominent sticking out of one eye
  • Torn or cut eyelid, or foreign object under the eyelid/on the eye
  • Blurred vision or restricted movement of one or both eyes

What to Do In Case Of an Eye Injury

Go to a doctor immediately, even if the injury seems minor. Delaying could further damage the eye, leading to permanent loss of vision. You should take the following precautions too:

  • Don’t rub, touch or apply pressure to the hurting eye
  • Flush out any chemicals the eye has been exposed to with clean water
  • Do not self-medicate
  • Don’t try to remove any foreign object stuck in the eye
  • Shield the eye with a gauze patch till you get medical attention

For any eye-related query or treatment, get in touch with InSight Vision Center today!

Age-related eyesight

Just as you experience the very unfortunate effects of aging like decreasing physical stamina, your eyes also exhibit an age-related decline in performance; especially after the age of 60.

Some people will experience more serious age-related eye diseases, which should be treated immediately. The common age-related eye problems are:

Presbyopia:

Presbyopia is just the gradual loss of the ability to see close by objects; this means that you can’t read books, sew or chop vegetables properly without a pair of reading glasses.

Floaters:

Floaters are an increasingly common ailment. They are those tiny specs or spots that float across the field of vision when we see bright lights. Remember seeing floating spots everywhere after a camera flash or those irritating flecks that appeared in your visual periphery out of nowhere after you stared directly at the sun? Those are floaters.

Though most often they are a benign problem, sometimes they may indicate the beginning of a more serious eye problem like retinal detachment.  If you notice a sudden change in the type or number of spots or flashes you see, visit your eye doctor as soon as possible.

Dry Eyes:

This is a common ailment, especially if you watch a lot of TV or sit in front of the computer a lot. This happens when tear glands cannot make enough tears or produce poor quality tears. Dry eyes can be uncomfortable, causing itching, burning, or in extremely rare cases, loss of vision.

Tearing:

Another not so serious eye problem, excessive tearing can cause a lot of itching and uncomfortable sensations in the eyes. If you are extremely sensitive to light, wind, or temperature changes, you might be plagued by this problem.

Cataract:

Cataracts are one of the most common health problems among old people. The symptoms are:

  • Cloudy, blurry or dim vision
  • Difficulty seeing at night
  • Sensitivity to light and glare
  • Fading or yellowing of colors

Cataracts, though not preventable can be corrected with a simple, no stress surgery.

Glaucoma:

Glaucoma, most commonly associated with diabetics, occurs because of unusually high pressure inside the eye. This pressure damages nerve fibers that carry visual information from your eye via the optic nerve to your brain. Advanced glaucoma can lead to patients seeing blind spots in their visual field. Glaucoma should be detected immediately because if it is left untreated, glaucoma can lead to irreversible blindness.

Retinal disorders:

The retina (a thin lining on the back of the eye) collects visual images and passes them on to the brain. Retinal disorders interrupt this transfer of images. Retinal disorders include age-related macular degeneration, diabetic retinopathy, and retinal detachment.

Conjunctivitis:

The pink eye’ causes redness and inflammation of the thin layer of tissue that covers the front of the eye because of a bacterial infection. Conjunctivitis can affect one eye at first, but usually affects both eyes after a few hours. It is an easily treatable disease with the help of a right doctor.

Corneal Diseases:

Disease, infection or injury to the cornea can lead to irreversible damage and compromise your visual faculties. The cornea is the clear, dome-shaped “window” at the front of the eye. It helps to focus light that enters the eye hence is a very important part of the eye.

Eyelid Problems:

Droopy eyelids, blinking spasms or infected and inflamed outer edges of the eyelids near the eyelashes are common eyelid problems. This can cause pain, itching tearing, and sensitivity to light.

Temporal Arteritis:

When the temporal arteries which supply blood to the head and brain become inflamed or damaged, they can cause severe headaches, pain when chewing, and tenderness in the temple area. It may be followed by sudden vision loss in one eye. Other symptoms can include joint pain, weight loss, and low-grade fever.

The best solution to combat eye problems is early prognosis and detection. If you ever feel like you are experiencing these symptoms, then it would be best if you contact an eye doctor at InSight Vision Center, Fresno CA, immediately. Remember prevention is better than cure.

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