Can you diagnose eye diseases by looking at a photograph?

Screen Shot 2014-04-07 at 9.13.27 AMFox News recently covered a story about how a rare and serious eye condition was discovered on Facebook because friends noticed something strange when a mom posted a picture of her child. One of the child’s pupils was white.

A white pupil, otherwise known as leukocoria, may indicate a serious eye condition.

How is leukocoria observed?

Leukocoria occurs when the pupil is white instead of black. Leukocoria may be detected in a photograph when one pupil has an abnormal reflex or “white reflex” compared to the other eye having a normal “red reflex.” The red reflex is either absent or white with leukocoria due to an abnormal light reflection from the eye. If leukocoria is pronounced, the pupil may appear white while observing the other person. This is easier to inspect in a darkened room.

What is a red reflex?

A red reflex is the normal reaction when light enters the eye through the pupil. The retina absorbs most, but not all, of the light and what is reflected back is reddish-orange in color – the “red eye” you see in pictures.

How is leukocoria diagnosed?

Doctors of optometry use an instrument called a retinoscope to examine the eye to determine if that normal red reflex is present. An ophthalmoscope is used to view the inside of the eye. The doctor also dilates the eyes a in order to evaluate them more thoroughly.

What causes leukocoria?

Many conditions cause leukocoria including cataracts, retinal detachment, retinopathy of prematurity, retinal malformation, an infection such as endophthalmitis, retinal vascular abnormalities, and intraocular tumors such as retinoblastoma.

These are all serious eye conditions which may be a vision and/or life threatening emergency.

If a white reflex or leukocoria is detected, schedule an eye examination immediately.

What is the treatment for leukocoria?

The treatment is to manage the underlying condition.  Early treatment is crucial. Treating the underlying condition promptly can save both vision and a person’s life.

~Melissa Barnett, OD, FAAO
California Optometric Association
http://eyehelp.org
http://www.coavision.org

Color blindness – the causes and the effects

When we think of someone being color blind, we may think that he sees the world in black and white, or shades of gray.  But that is extremely rare.  In fact, almost 8% of men have some form of color vision deficiency where certain colors are more difficult to distinguish, or do not appear as vivid as other colors.  (Perhaps that explains the questionable wardrobe choices my husband sometimes makes.)

What causes it?

Most cases of color vision deficiency are inherited and passed down from the mom.  The photoreceptors in the retina responsible for color are called cones.  Each cone is sensitive to a certain color, in particular, red, green or blue.  If a person has inherited a recessive gene that causes one or more of the cones to be absent or to not function properly, then he will have abnormal color perception.

Photo courtesy of entirelysubjective on Flickr

Photo courtesy of entirelysubjective on Flickr

Some cases of color vision deficiency are acquired later in life as a result of a disease.  More common causative diseases are glaucoma, macular degeneration, and diabetes.  If you notice a change in your color vision, make sure to be evaluated by your optometrist. For eyecare providers, we tend to distinguish color vision deficiency into two broad categories.  Red-green and blue-yellow.  Red-green is inherited and the most common deficiency.  Those with this defect can still see red and green, but the colors are more difficult to distinguish and they may not appear as vivid as to the normal eye.  For example, red and green signal lights may look the same.  One may appear brighter but the lights may both look white.  (For this reason, I’m not a fan of the horizontal traffic lights in some smaller towns.)  Most people who have color vision deficiency have a mild form and are not disabled by this condition.

The other form of color deficiency is blue-yellow where patients have a difficult time distinguishing blue from green or yellow from violet.  This is less common and is usually caused by certain eye diseases.  Unfortunately, for many of these patients, color deficiency is just one visual problem among others.  These patients may also suffer from dimming of vision or distortion of vision.  Often times, bright lighting is helpful for these patients, and occasionally tinted lenses. 

How can I help someone that’s color deficient?

Of course, a comprehensive eye examination is important to rule out any causes of color vision deficiency other than genetics.  This also helps to determine the severity.  Most color deficient individuals carry on like normal without it interfering with their daily lives.  A helpful tip would be to not use the colors red and green as markers because the two colors may appear very similar.  Blue and red will be easier to distinguish.  Unfortunately, those with color vision deficiency should avoid careers that require distinguishing color differences such as airplane pilots, paint mixer, interior designer, etc.

Recently, new developments in tinted lenses have been able to allow some color vision deficient patients be able to see colors they have never seen before.  Sounds promising!

~Cindy P. Wang, OD, FAAO
California Optometric Association
http://www.coavision.org

I have an astigmatism. What is that?

Courtesy of Greece Trip Admin on Flickr

Courtesy of Greece Trip Admin on Flickr

Astigmatism is a term used by optometrists to describe a prescription for one eye that needs two powers to bring it into focus. It is not a disease or something that will make you go blind, but it can make things blurry at distance and at near.
Most people are familiar with the terms “near-sighted” and “far-sighted.” In the eye care world we use the term “myopia” for near-sightedness and “hyperopia” or “hypermetropia” for far-sightedness. These terms are used to describe the power (+ or -) of the lens needed to make you see clearly.
If your prescription needs only one power to bring your eye into focus then you can think of it as being simple. So if your prescription has a number like -4.00, then you have simple myopia. Similarly, if you have a prescription of +2.25, then you have simple hyperopia.
If you have an astigmatism in your eye, then you have two powers that need to be corrected for you to see clearly. Having an astigmatism in your eye is our way of describing a compound prescription. Instead of just one simple power like we described earlier, there are two powers together. Depending on your prescription, you can have myopia with astigmatism or hyperopia with astigmatism.

Courtesy of Ciro Boro - photo on Flickr

Courtesy of Ciro Boro – photo on Flickr

A common example optometrists use to describe astigmatism to patients is the difference between a basketball and a football. A basketball is nice and round, and has only one curve for the entire ball. You can think of that curve as a lens power. A basketball is a good example of a simple prescription. A football, on the other hand, has two curves. This is like an eye that has two powers or an astigmatism.
Astigmatism is not an eye disease, but rather a term we optometrists use to describe a compound prescription in one eye. So don’t be alarmed if your optometrist tells you that you have some astigmatism in your eyes. You are not alone – I have an astigmatism in both of my eyes and I see extremely well!

~Ranjeet S. Bajwa, OD, FAAO
California Optometric Association
http://www.coavision.org

Night blindness 101

The term night blindness sounds alarming, as though some people are actually blind at night.  There is a small percentage of the population that does in fact experience true night blindness, but it is rare and often the result of late stage eye disease.  In optometry, it is not common to use the term night blindness although we do encounter a significant number of patients who complain of poor night vision.  The symptoms are usually blur and dimming of vision at night, glare and haloes around lights and poor adaptation from light to dark environments.  How do you know if what you are experiencing is normal or a result of something more serious?

There are a handful of eye conditions that can create symptoms of poor night vision.

Photo Courtesy of kenleewrites on Flickr

Photo Courtesy of kenleewrites on Flickr

  1.  Patients who have had surgery to the corneas such as LASIK or corneal transplants may notice glare and haloes around light.  They may also experience diminished contrast sensitivity which can cause images in the evening to appear more dim.  Unfortunately, surgical results usually cannot be reversed.
  2. Cataracts are the number one cause of decreased night vision.  Patients over the age of 40 will begin developing mild cataracts.  This is when the natural lens inside the eye becomes more yellow and opaque as a result of age and ultraviolet exposure.  Cataracts can cause haloes and dimming of vision in the dark and decreased contrast sensitivity.  Fortunately, cataracts are easily removed thereby restoring problems with night vision.
  3. Corneal diseases such as keratoconus and severe dry eyes may also affect one’s vision in the evenings causing double vision or haloes.  For some of these patients, specialty contact lenses or eyedrops will alleviate these symptoms.
  4. Newer technology has also allowed optometrists to detect higher order aberrations in some patients.  For these patients, standard spectacle lenses may not improve night vision problems.  An instrument to detect higher order aberrations will determine whether a patient requires a specialty custom-made spectacle lens to improve night vision.

Some patients do in fact have true night blindness caused by an eye disease in its late stage.  Usually, symptoms begin slowly over time and progress to an inability to see in the dark.  These patients usually suffer from one of two eye conditions.

  1.  Retinitis pigmentosa is an inherited eye disease of the retina, the tissue that lines the back wall of the eye and captures visual images.  Retinitis pigmentosa affects the rods of the retina and causes slow deterioration of these structures.  The rods (unlike the cones) are responsible for night vision and for peripheral vision.  As the disease progresses, patients will notice a decrease in their ability to see in the dark and in the periphery.  Unfortunately, there is no current cure for retinitis pigmentosa.
  2. Glaucoma is an eye disease where the optic nerve slowly degenerates.  Patients with glaucoma usually have no symptoms in the early stages of the disease.  As the disease progresses, nerve fibers in the retina begin to deteriorate resulting in a decrease in peripheral vision as well as night vision.  Usually, patients do not experience symptoms of poor night vision and poor peripheral vision until the late stages of the disease.

Now that you know the causes, what are some ways to alleviate or improve poor night vision?  The simplest solution is to wear an updated pair of prescription glasses (if you have a prescription) with higher index lenses and an anti-glare coat.  Your optometrist can also inform you if you require customized lenses to correct for higher-order aberrations.  If your night vision problems are not a result of surgery or any eye diseases that you are aware of, then it is important that you visit your optometrist for a comprehensive eye examination.

– Cindy P. Wang, O.D., F.A.A.O.
California Optometric Association
www.coavision.org