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Eye diseases in the United States are relatively common and are the leading cause of blindness, vision impairment, and low vision. Glaucoma, diabetic retinopathy, strabismus, macular degeneration, and other age-related eye conditions cause the individual to lose their vision over time and may potentially cause permanent legal blindness. 

Over 4.2 million Americans over the age of 40 are considered legally blind or have low vision in the better seeing eye. “Normal” vision is 20/20, meaning an individual reading the Snellen eye chart can read a designated line of letters while standing at 20 feet away. A person with 20/20 vision can see certain objects at 40 feet that a person with 20/40 vision can only see at 20 feet. 

Legal blindness is considered 20/200 vision. Individuals who are legally blind may be able to read the words “STOP” on a sign, but struggle to interpret anything smaller. Refractive errors are the most common eye issues and are easily treatable. Other eye diseases cause more harm than refractive errors, however, the field of ophthalmology is ever-expanding, seeking cures for common eye problems so that people may keep their sight. 

Anatomy of the Eye

The eye is a complex structure that is responsible for capturing light in the form of images and transmitting those signals to the brain. Through our eyes, we are able to interpret the world around us. Here’s how they work. 

Iris. The iris is the colored circle around the pupil and is responsible for letting light in by opening and closing the pupil. 

Retina. Containing millions of light-sensitive cells, the retina is responsible for taking in and organizing visual information, before passing it along the optic nerve to your brain. 

Cornea. This clear tissue sits in the front of the eye and acts as the eyeball’s lens, helping it focus. 

Pupil. Letting light into the retina remains the central focus of the pupil. 

Lens. Located behind the pupil and iris, the lens is a flexible tissue that allows light and images to focus on the retina. 

Uva. The middle layer of the eye that lies behind the white portion and controls many functions of the eye. 

Macula. Part of the retina, the macula is responsible for our central vision, color, and clarity. 

Optic nerve. Composed of over 1 million nerve strands, the optic nerve sends signals from the eye to the brain. 

Vitreous. This gel-like fluid fills the eye and is full of small fibers that attach it to the retina.

What are the most common eye diseases and disorders? 

There are numerous eye problems, eye disorders, and eye diseases that can affect human beings at any age. Here, we will cover the more common ones, their symptoms, and treatments. 

  • Refractive errors. Refractive errors are the most common eye issue and typically include myopia (nearsightedness), hyperopia (farsightedness), astigmatism (skewed distant vision), and presbyopia (aged-related inability to read up close). Symptoms include: 
    • Blurred vision
    • Hazy vision
    • Double vision
    • Halos around lights
    • Headaches
    • Squinting
    • Eye strain 
  • Cataracts. This clouding of the eye lens can affect anyone, however, it is more common in older adults. Common causes of cataracts are related to the body’s aging process. This eye disorder is the leading cause of blindness worldwide, but is treatable in most cases. It is estimated that 30.1 million individuals in 2020 suffered from cataracts. Symptoms include:
    • Seems like one is peering through a cloudy window
    • Blurred vision
    • Adding or yellowing of colors
    • Needing increased light to read things
    • Difficulty seeing at night
  • Diabetic retinopathy. A complication from diabetes, diabetic retinopathy afflicts the blood vessels in the retina. It progresses in four stages – microaneurysms, blockage in some blood vessels, additional blockage eliminating the possibility of growing new blood vessels, and permanent retina damage or vitreous hemorrhaging. Symptoms include:
    • Floaters (shapes floating in vision)
    • Sudden vision loss
    • Blurred or patchy vision
    • Gradually worsening vision
  • Uveitis. This catch-all term relates to any inflammation in the eyes that affects the uvea. Uveitis is an eye infection of the middle layer and can occur suddenly (acute) or can recur throughout life (chronic), needing constant management. Uveitis symptoms are vast and varied but may encompass the following:
    • Eye redness
    • Floaters that resemble dark spots
    • Eye pain
    • Sensitivity to light
  • Amblyopia. Often colloquially referred to as “lazy eye”, Amblyopia occurs when one eye is not as strong as the other, so the brain chooses not to use it. From the outside, the eye appears normal, but it typically suffers from a refractive error of some type. 
  • Age-related macular degeneration. Also called macular degeneration, this eye disease is most associated with aging and damages the sharp, central vision. Wet AMD occurs when abnormal blood vessels in the retina begin to grow under the macula. Dry AMD refers to the thinning of the macula over time, as one ages. It is much more common than wet AMD.
    • Recognizing straight lines as wavy
    • Drusens (yellow or white deposits around the retina)
    • Fuzzy vision
    • Blurred areas on printed pages
  • Glaucoma. When intraocular pressure builds at the back of the eye due to poor drainage, glaucoma may occur. Open angle and closed angle glaucoma can eventually lead to blindness. 
    • Eye pain
    • Severe headaches
    • Nausea and vomiting 
    • Halos around light 
  • Dry eye disease. When the eyes can’t produce enough tears on their own, one may be experiencing dry eye disease. 
    • Scratchy eyes
    • Stinging, burning sensation in eyes
  • Color Blindness. Usually, individuals with this eye disorder are born with it, but it can be caused by certain drugs or diseases. Color blindness affects more men than women and can occur on a spectrum of severity. 
  • Strabismus. Strabismus occurs when the positioning of the eyes in their sockets is not symmetrical (crossed eyes). It may cause the crossing of one eye and prohibit the individual from focusing on the same point. In some cases, strabismus may lead to vision loss in the affected eye. 
  • Conjunctivitis. Also called pink eye, this common eye disorder usually clears up on its own. 
    • Gritty feeling in the eye
    • Leaking fluid 
    • Itchiness
    • Red eyes
  • Corneal diseases. Corneal disease may be caused by injury, disease, or infection. The three major types of corneal disease are keratoconus, bullous keratopathy, Fuchs’ endothelial dystrophy. The cone-shaped window at the front of the eye gets damaged and may eventually lead to blindness. 
    • Wearing contact lenses becomes difficult
    • Glare in sunlight or with artificial lights at night

Treatments for Common Eye Diseases

Depending on the eye disease one is suffering with, treatments and cures may vary. 

  • Corrective lenses
    • Glasses or contacts can be prescribed from a very young age. Corrective lenses and contacts will most likely need to be adjusted as one ages. The following common eye diseases may be treated with eyeglasses or contact lenses.  
      • Refractive errors 
      • Corneal disease (early stages)
      • Amblyopia 
      • Strabismus 
      • Color Blindness
  • Surgery
    • Surgeries such as cataract surgery or LASIK surgery can correct vision problems related to cataracts, refractive errors, strabismus, and amblyopia. Laser treatments are also available and are typically considered outpatient procedures, performed in-office by the eye doctor. Laser surgeries may be used to treat the following:
      • Age-related macular degeneration
      • Glaucoma
      • Diabetic retinopathy
  • Eye drops or creams
    • Testosterone creams, real tear drops, prescription eye drops like corticosteroid-based drops can help with a number of eye issues. 
      • Glaucoma. 
      • Dry eyes. 
      • Uveitis
      • conjunctivitis
  • Good hygiene.
    • Washing hands regularly, using a new face towel, and cleaning makeup brushes or other eye-related products can help minimize certain eye disorders. Eye care, like taking vitamins, using natural products, and minimizing blue light interactions is equally helpful in fostering eye health. Stay away from irritants like chemical fragrances, cigarette smoke, and pollution. 
      • Pink eye, styes, cysts, irritation, dry eyes, or overproduction of tears can be linked to lifestyle factors. 

Your Vision is of the Utmost Importance

The human eyeball is a complex mechanism that allows us to interpret and interact safely and efficiently with our world. Maintaining good eye health as one ages can increase one’s independence and quality of life. 

Establish a relationship with an ophthalmologist in Orlando and be sure to schedule yearly eye exams. Routine examinations may help catch some eye disorders early on and prevent additional vision loss or permanent blindness. UCF Health’s patient portal empowers our community to take charge of their health. Our online scheduling tool, COVID-19 updates for patients, and wellness resources encourage individuals to make healthy living a priority.