Problems with Vision

Emmetropic the normal condition of the eye in which visual images are in clear focus on the retina

What is 20/20 Vision? A "normal" human being should be able to see when standing 20 feet away from an eye chart. 20/20 Vision means that when you stand 20 feet away from the chart you can see what the "normal" human being can see. 20/100 means that when you stand 20 feet from the chart you can see what a normal person standing 100 feet away can see. 20/200 is the cutoff for legal blindness in the United States. So, can you have better than 20/20 vision? Yep….20/10 can see at 20 feet what a normal person can see when standing 10 feet away from the chart.

Hyperopia “Farsightedness” Objects far away are clear but close objects are blurry. Light is focused on a point behind the retina. Cause: Eye is shorter in distance than normal. Signs: Trouble seeing up close Headaches – due to eye strain Eye fatigue when reading

Solution: Glasses that are convex (thickest in the center). Allows light to refract through the lens changing the focal point

Hyperopia can be corrected by wearing a convex (converging) spectacle lens. The rays of light from a near object are converged before entering the eye so that the cornea and eye lens can direct the focal point onto the retina.

Myopia “Nearsightedness” Objects close are clear but objects far away are blurry. Light is focused in front of the retina. Cause: The eyeball it too long. Signs: Difficulty seeing the chalkboard Difficulty seeing things in the distant

Solution: Glasses that are concave (thicker on the edges)

Myopia can be corrected by wearing a concave (diverging) spectacle lens. The rays of light from a near object are diverged before entering the eye so that the cornea and eye lens can direct the focal point onto the retina.

Eye Care Professionals Ophthalmologists Medical Doctors who provides full eye care gives you a complete eye exam prescribes corrective lenses diagnoses and treats complex eye diseases performs eye surgery

Optometrists is a Doctor of Optometry – Not a Medical Doctor evaluates your vision Prescribes corrective lenses diagnoses common eye disorders and treats selected eye diseases with drugs will likely refer you to an ophthalmologist for more complex eye problems and for conditions requiring surgery.

Opticians fill prescriptions for eyeglasses assembling, fitting and selling them. sell and fit contact lenses.

Common Problems of the Eyes

Glaucoma A group of conditions that can damage the optic nerve causing vision loss or blindness. Due to fluids in the eye not draining properly leading to pressure build up causing damage to the optic nerve. Signs/Symptoms None at first Peripheral vision fails Loose peripheral vision altogether making feel as though they are looking in a tunnel. Who Gets It? African American Genetic Can happen due to trauma

Testing During routine eye exams, a tonometer is used to measure your intraocular pressure. Your eye typically is numbed with eye drops, and a small probe gently rests against your eye's surface Or a small puff of air is puffed onto your eye's surface. Treatment Eye drops Continual eye care and exams

Cataracts Clouding of the lens (behind iris and pupil). That lens is made of protein and water. Proteins are aligned in a way to make the lens appear clear, can see through it. Proteins that are miss aligned causes a cloudy appearance. Will start out small and end in all of the lens becoming cloudy.

Occurs from Treatment Unknown Exposure to UV rays – wear your sunglasses Age Medication – steroids Diabetes Treatment Wearing glasses, reducing light until worse Surgery the surgeon will remove your clouded lens and replace it with a clear, plastic intraocular lens. What type of “Surgeon” would perform this surgery?

http://www.youtube.com/watch?v=Go82c4f1emc Surgery Animation

Macular Degeneration Leading cause of vision loss in Americans Affects the macula of the eye (the retina) Due to The gradual breakdown of cells in the macula (“Dry Form”) Gradual blurring in center of vision Abnormal blood vessels in the retina, leak/bleed causing scarring of the retina (“Wet Form”). Can progress quickly

Cause: Signs and Symptoms: Unknown Genetic Race = Caucasian Age = Older, more chance Females Light eyed (iris color) Medication Signs and Symptoms: Blurred close-up vision Blind spots Objects are smaller in one eye than another

Treatment Test – Amsler Grid Vitamins Use of vision aids and machines Magnifying glass Talking watches, clocks Can not be fixed Test – Amsler Grid Cover one eye Look at dot in center of grid. If lines look wavy, = problem

Positive test for Macular Degeneration

Retinitis Pigmentosa Condition in which damage occurs to the retina Rods and cones die within the retina Occurs gradually and worsens with time Cause Genetic (several different gene mutations that can result in this condition) Symptoms Rods are usually affected first leading to diminished peripheral vision and night vision (driving) Bumping into objects Tunnel vision When cones start dying, your color vision diminishes

Treatments New studies show that Vitamin A and DHA (omega-3) helps Use of vision aids and machines Magnifying glass Talking watches, clocks No cure at this time