The Retina & Retinal Eye Exams

The light-sensitive tissue that lines the back of the inner eye is called the “retina”. Images that you look at are projected through the pupil and focused onto the retina. The rod and cone cells in the retina then convert that image into electric signals, which are then sent to the brain through the optic nerve. Understandably, the retina is vital to your visual system, and if damaged or diseased, can cause blindness or loss of vision.

There are 3 important structures in the retina:

  • Optic Nerve: The ‘wire’ that connects the eye to the brain. This nerve carries visual signals to the brain, much like the cables that connect a DVD player to your TV.
  • Macula: This is the area of the eye with the highest density of rods and cone cells. Much like more pixels in a digital photo give you a clearer higher resolution image… the higher density of rods and cone cells in the macula give you more detailed and higher resolution central vision.
  • Retinal Blood Vessels: These are the arteries and veins that feed the eye nutrients and oxygen and are responsible for removing waste materials. The retina needs a constant blood supply to function properly and provide good vision.

There are many diseases and disorders that can affect the retina. Systemic disorders such as high blood pressure, high cholesterol, diabetes, atherosclerosis, blood disorders, and many more can negatively affect retinal health. External factors such as accidents/injuries, UV light, lasers, smoking, occupational hazards, and medications can also cause damage to the retina and affect your vision. Some conditions like glaucoma, macular degeneration, retinal detachments/holes, can have some genetic inheritance ? but can also occur spontaneously in individuals with no family history of these issues.

Because there are so many known (and unknown) conditions that can cause problems for the retina, it is important to have the health of your retina assessed yearly at your comprehensive eye exam – even if you do not wear glasses or have perfect vision.

The latest technology that we have to screen central retinal health is the retinal camera. This camera uses a special set of focusing lenses to take a quick and painless digital image of your retina. Most of the time, good images can be taken without dilation eye drops, and there are no side effects (other than the temporary brightness from the camera flash). In addition, these photos can be used as a baseline to look for changes that can occur to your retina through the years. Although this instrument is not yet considered the standard of care, it is quickly becoming so. In our office, we offer digital retinal photography to all patients for a nominal fee, and are happy to email these photos to our patients at no charge.

A more comprehensive way to assess eye health is with the dilated eye exam. Without dilating the pupils, peripheral portions of the retina are not viewable. It is important to view these parts of the retina in order to properly assess eye health and screen for potentially vision threatening conditions. The dilation also allows for a much more thorough assessment of the central retina, as it increases the field of view for the doctor to see inside the eye – much like viewing the inside of a room is easier through a big open doorway vs. an old fashioned keyhole in the door. In order to dilate the eyes, the technician or doctor will put eye drops into the eyes, and when the pupil widens, the doctor will exam the retina using a special head-mounted scope. In my office, we offer the dilated eye exam free of charge within 30 days of your comprehensive eye exam. The main side effects of dilation include blurry vision, light sensitivity, and inability to focus for a few hours ? because of this; it is usually a good idea to have a driver take you home.

Ask your eye doctor for more information on how you can keep your retina healthy, and what tools they use to check your retinal health.

-Dr. Mika Fu

Yearly Comprehensive Eye and Vision Exams

Regular eye and vision exams play an important role in preventative health care, even for people with “perfect” vision. There are many serious eye problems and diseases with no obvious signs or symptoms, and people may not aware that these problems exist until the damage is already done. Early diagnosis and treatment of eye and vision issues is essential in keeping the eyes healthy and preventing vision loss.

What goes on during an eye exam? A proper comprehensive eye exam is more than just checking for a prescription. During a comprehensive eye exam, the doctor will conduct a number of tests to determine status of vision and eye heath:

  • Patient History: symptoms, health problems, medications taken, occupational/environmental concerns.
  • Visual Acuity: how clearly each eye is seeing.
  • Eye Pressure: to check for glaucoma and other eye diseases.
  • Visual Field: assess your side vision to check for any problems with the nerve or visual pathway.
  • Refraction : to check for your glasses prescription if you are nearsighted, far-sighted, have astigmatism, or have focusing problems.
  • Eye focusing, Teaming, & Depth Perception: to assess how the eyes work together.
  • Color Vision: to check for reduced color perception or blindness.
  • Microscope evaluation of the eye: to check the health of the eye surface (cornea, conjunctiva), and the interior of the eye (iris, pupil, intraocular lens, optic nerve, and a portion of the retina.
  • Dilation & Retinal Photography: to assess the health of the retina.
  • Additional testing as needed: contact lens services, red eye evaluation, dry eye, etc..

Many people are under the misconception that if they can “see fine”, they do not need an eye exam. This could not be further from the truth. Several years ago, a young mom with “perfect vision” brought her daughter in for her first exam because she couldn’t see the board in class. Her daughter was apprehensive, so the mother decided to have an eye exam first and let her daughter watch (to calm her fears and show her nothing ‘scary’ would happen). During that exam, we found a suspicious looking spot in the mother’s eye and referred her to a specialist. It turned out, the mother had never had an eye exam before (since she always had “perfect vision”), and the “suspicious looking spot” was actually a slow-growing malignant tumor – which thankfully, the surgeon was able to remove since it was detected early! Although this scenario does not happen every day in my office, it happens often enough that I worry about those individuals who never have their eyes checked.

Comprehensive eye examinations are recommended once a year for individuals who wear glasses/contacts or have risk factors (e.g. diabetes, high blood pressure, use of certain medications, eye disease, family history of eye disease, crossed eyes, or other health conditions/concerns). For asymptomatic individuals (people with “perfect vision”), eye exams are recommended at the following intervals:

  • Birth to 24 months: At 6 months of age
  • 2 to 5 years: At 3 years of age
  • 6 to 18 years (school-aged children): Annually
  • 18 to 59 years: Every two years
  • 60 and older: Annually

It is especially important that school-aged children are seen for comprehensive eye exams on an annual basis (1st grade through 12th grade). During these years, children’s bodies are growing and changing, and large changes in vision can occur rapidly. Although some schools perform quick “vision screenings” to help identify children who have undetected vision problems – many children still fall through the cracks and may “pass” the screening, delaying further examination and treatment.

If you can’t remember the last time you had your eyes checked, it’s time to call your doctor and schedule an appointment!

-Dr. Mika Fu

Advances in Contact Lenses Technology

As the New Year begins, many of us have made the resolution to exercise and live healthier lives. However, it can be difficult to exercise when glasses are bouncing up and down on your face, falling down, or fogging up as you run, bend, and stretch! For many people – even those who rely on progressive or bifocal glasses – contact lenses may be the solution to provide clear vision while enabling a healthy lifestyle. Contact lenses can also help people feel more confident in their appearance, and offer a respite for those that would otherwise have to wear thick and heavy glasses.

Many people have been told in the past that their eyes or their prescriptions were not suitable for contact lens wear. However, times have changed, and contact lens technology has significantly improved over the last few years. While before, choices were limited, these days there are numerous brands, materials, lens designs, and wear schedules that can fit almost everyone’s individual needs. For example:

  • Daily disposables: for the occasional wearer, children, or people with dry eye or allergies.
  • Monthly/Bi-weekly disposables: for the average contact lens wearer – someone who wears their contacts 5-6 days per week.
  • Toric or Astigmatic contact lenses: for people with moderate to high amounts of astigmatism.
  • Multifocal contact lenses: for people who need to wear reading glasses, bifocals, or progressives.
  • Custom made soft lenses: for people with extremely high or unusual prescriptions.
  • Rigid Gas Permeable “hard” contacts: for people with high or unusual prescriptions, corneal problems such as keratoconus, or for those that require very sharp crisp vision.

Contact lens materials have also changed significantly over the past few years. The last generation of soft contact lenses were made of plastic polymers which provided good comfort, but poor oxygen breathability. (Oxygen breathability is an important factor in safe and comfortable contact lens wear, as the cornea gets oxygen from the environment directly through diffusion – a contact lens sitting on the cornea can block that process.) The newest generation of contact lens materials offer superior oxygen breathability – silicone is incorporated into the polymer which allows more oxygen to pass through the contact lens directly to the cornea. These new materials can afford up to ten times more oxygen to the cornea than the previous generation of contact lenses, providing superior comfort and wearability.

For those who have been unable to wear contacts in the past due to dryness or dry eye – new research has shown that Omega-3 fish oil supplements (1200mg/day taken orally) can significantly improve the tear film. Many patients who were previously unable to tolerate contact lenses are actually now able to wear contact lenses comfortably for 8-10 hours with the introduction of fish oil into their daily vitamin routine. In addition, advances in re-wetting eye drop technology have improved the wearability of contacts while performing visually demanding tasks like computer use, reading, and long-distance driving.

Better contact lens care products have also enhanced the comfort and wearability of contact lenses. One-step hydrogen peroxide based cleaning systems such as Clear Care and OcuSoft offer a high level of preservative-free disinfection for those with sensitive eyes, or those who are allergic to various contact lens solution preservatives. The newest multi-purpose solutions (such as Opti-free Pure Moist, RevitaLens OcuTec, and BioTrue) offer increased comfort and moisture for everyday contact lens wear.

Ask your eye doctor if you are a candidate for contact lens wear, or if there have been any advances in contact lens technology that could be beneficial for your visual needs!

-Dr. Mika Fu

Common Eye Disorders

Information on some of the most common eye disorders:

Myopia (Near-sightedness)

In the U.S., 30% of the population is near-sighted. This is a common vision condition that is caused by a longer than average eyeball or by a steeply curved cornea. In near-sightedness, distance objects are “blurry” or out of focus, while near objects are “clear” or more in focus. Near-sightedness is easily treated with glasses and/or contact lenses, and tends to change the most during the childhood and teenage/young adult years.

Hyperopia (Far-sightedness)

Far-sightedness is a common vision condition caused by a shorter than average eyeball or by a flatter than average cornea. Many far-sighted people have excellent distance vision, by may notice eyestrain or headaches after prolonged reading or near work. More severe far-sightedness can cause blurry vision in addition to eyestrain, headaches, and eye fatigue. Far-sightedness is easily treated with glasses and/or contact lenses.

Presbyopia

Presbyopia is focusing problem that occurs to everyone starting around the age of 40. It is not a disease, and unfortunately, cannot be prevented as it is a normal part of the aging process. Over time, the crystalline lens inside the eye hardens and loses flexability. This makes it more difficult to focus on close objects and reading material. The most common complaint for people experiencing presbyopia is, “My arms are too short!” (Holding reading material further away requires less focusing from the eye.) Presbyopia is easily corrected with reading glasses, bifocals, progressive addition lenses (the “no-line bifocal”), multifocal contact lenses, and monovision with contact lenses.

Dry Eye

Dry eye has many causes. The most common causes of dry eye are deficient tear production, clogged tear glands, certain medications (like antihistamines, oral contraceptives, and antidepressants), and living in dry environments. Dry eye can cause stinging/burning of the eyes, a “gritty” sensation, irritation, redness, intermittent blurry vision, difficulty wearing contact lenses, and even watering of the eyes. It is important to see your eye doctor if you suspect you have dry eye, because excessive dry eye may scar the cornea, damage ocular tissues, and impair vision. Dry eye cannot be cured, but your eye doctor can recommend different treatments for the different types of dry eye to alleviate the symptoms and keep your vision intact and your eye tissues healthy.

Astigmatism

Astigmatism is a common vision condition that may occur along with either near-sightedness or far-sightedness. It is caused by an irregularly shaped cornea or intraocular lens, and can cause blurry distance and near vision. Astigmatism is easily treated with glasses or “toric” contact lenses.

Cataracts

Cataracts occur when the crystalline lens inside the eye turns cloudy or opaque, most often in people over the age of 55. It can cause blurry vision that is not correctable with glasses or contact lenses, and can cause problems with glare (especially at night), and can cause a change in color perception. Unprotected Sun/UV exposure can increase the likelihood of cataracts, so it very important to wear sunglasses with a proper UV coating when outdoors to decrease the chances of getting a cataract.