Tuesday, December 23, 2014

Merry Christmas!

Wishing you all a very merry Christmas and a happy New Year!

Friday, December 19, 2014

contact lens DOs and DON'Ts

Cutest contact lens case in history? Obviously.
While many people wear contact lenses without ever having any issues or complications, thousands of Americans are affected annually by contact lens-related eye infections.  In my own experience treating such cases, many, if not all, are due to poor contact lens hygiene and/or contact lens abuse.  A recent American Eye-Q® survey (1found that, among contact lens wearers:
  • 57% admitted they wore disposable contacts longer than directed
  • 54% reported they waited 4 to 6 months or longer to change contact lens case
  • 39% stated they did not clean lenses with a multipurpose solution daily
  • 35% said they did not wash their hands prior to handling lenses
  • 26% stated they wore lenses while swimming
  • 21% reported they slept in contacts
Those are dangerously high percentages! So this blog post is my attempt to help spread the word on contact lens hygiene.  Here are my "DOs and DON'Ts" of contact lens wear.   
1. DO wash and dry your hands thoroughly before touching your contact lenses.  Your fingers have a ton of germs on them, and your contacts can act as a vector, transmitting bacteria to your eye (2).

2. DO remember to care for your case.  Rub and rinse your contact lens case with contact lens solution (not water), and store it upside down on a clean tissue.  Change your case AT LEAST every 3 months- I would recommend monthly.  A study done in 2010 showed that, on average, well over half (as many as 81%) of the contact lens cases tested were contaminated (3).  

3. DO clean your contact lenses regularly.  When removing your contact lenses, place the lens in the palm of your hand and pour multi-purpose solution onto the lens.  Gently rub the lens with your finger and rinse the lens with solution.  THEN you can put the lens in a clean case, fill with fresh solution, and store.  Researchers have demonstrated that the most effective cleaning regimen involves rubbing AND rinsing contact lenses before storage (4).

4. DO remove lenses and see your optometrist immediately if you experience eye redness, pain, discharge, sensitivity to light, or blurred vision.  These are often symptoms of an eye infection, and should be addressed quickly to avoid further complications.  

5. DO have a back-up pair of glasses. In the event that you lose a contact or have to be out of your contacts due to an infection, having a pair of glasses is a must.

6. DO see your eye doctor every year.  Even though you may feel your prescription hasn't changed (and it may not have), a yearly exam and contact lens evaluation allows your eye doctor to check the health of your eyes as well as your vision.
1. DON'T swim or shower or go in a hot tub with contact lenses in. The goal is to keep water away from your contact lenses, because water contains all sorts of nasty microbes. When those microbes come in contact with your lenses, they can adhere to them and infect your cornea (the clear part of the front of the eye). A certain parasite found in water and soil called Acanthamoeba can cause a rare but very serious infection that is difficult to treat (Google "Acanthamoeba keratitis"- the images will scare you straight).  Some studies have concluded that one-third of Acanthamoeba keratitis cases are associated with swimming, and the risk of infection with this parasite is six times greater when swimming in contact lenses (5). For safe swimming and water sports, consider talking with your eye doctor about the option of prescription goggles. If contact lenses must be worn, reduce your risk of complications by wearing daily disposable contact lenses with air-tight goggles, trashing the contacts once you're out of the water. 

2. DON'T wear your lenses for longer than your eye doctor recommends.  I come across many patients that do this in order to save money.  I can pinch a penny with the best of them, so I can certainly understand the motivation behind this.  But trust me when I tell you that the cost of treating an eye infection (multiple office visits, prescription eye drops, etc) could cost you far more than what you could save by stretching out your lenses.  Not to mention the fact that you only get one pair of eyes, so the risk really isn't worth it.

3. DON'T "top off" the existing solution that remains in the case.  The used solution has been exposed to microbes from your contact lenses and from the case. Dump out all of the old solution in the case, clean the case, and use fresh multi-purpose solution every time you store your lenses.

4. DON'T sleep in your contact lenses.  Some contact lenses are FDA approved for extended wear, but I personally do not recommend sleeping in any soft lenses.  Sleeping in contact lenses increases your risk of infection- studies show anywhere from a four to ten times greater risk (6,7).  If you are using extended wear contact lenses, make sure you take them out at least once a week to clean and disinfect them overnight.  If you are considering extended wear contact lenses, I encourage you to talk to your optometrist and discuss the risks/benefits. 

5. DON'T wear any type of contact lens- even cosmetic or costume lenses that don't provide visual correction- without a prescription.  Contact lenses are FDA classified as medical devices, and require a valid prescription from an eye care professional.

After reading this list, it's probably not hard to see why I'm a big fan of daily disposable contact lenses.  You eliminate most of these areas of risk- no case, no solution, no cleaning regimen.  Convenient and safe.  We'll talk in more detail about daily disposable lenses in a future post.  

CliffsNotes- DO: wash your hands, rub and rinse CLs, rub and rinse case, take CLs out and see optometrist if experiencing problems, have a pair of back-up glasses.  DON'T: let water come in contact with CLs, stretch the life of CLs, re-use existing solution, sleep in CLs, buy/wear CLs without a valid Rx.  

Additional recommended resources:

Friday, November 14, 2014

diabetes and the eye

Today is World Diabetes Day, and this month is American Diabetes Month, so it seems like a great time to talk about diabetes!  I would venture to guess that almost everyone reading this post either knows a person with diabetes or has diabetes themselves.  According to the 2014 Center for Disease Control (CDC) National Diabetes Statistics Report 9.3% of the US population has diabetes, and 27.8% of those with diabetes are undiagnosed.  That means nearly 1 in 10 Americans have diabetes, and more than 1/4th of those with it don't know it.  The increasing prevalence of diabetes has been referred to by many as a global epidemic.  In this post, we'll briefly go over what diabetes is, and then we'll go into detail about how diabetes affects the eye.

What is diabetes?  Diabetes is a group of diseases characterized by high blood glucose levels as a result of either a problem with how insulin is produced or how insulin works, or a combination of both.  Glucose is the body's main source of energy, derived from the food we eat.  Insulin is a hormone that allows glucose to be absorbed from the blood and converted to energy.    
  • In Type 1 diabetes, the body attacks the beta cells of the pancreas, which are responsible for producing insulin.  As a result, the pancreas produces too little or no insulin.  So a person with Type 1 diabetes depends on outside sources of insulin, such as insulin injections, insulin pumps, or even inhaled insulin, to be able to metabolize glucose.  This type of diabetes is typically diagnosed early in life, and it accounts for about 5% (CDCof diabetes cases.  
  • In Type 2 diabetes, the body either doesn't produce enough insulin or the cells of the body don't use the insulin produced properly.  Most people with this type of diabetes are able to achieve blood glucose control with diet, physical activity, blood glucose monitoring, and oral medication as needed, although some require insulin therapy.  Type 2 diabetes is usually diagnosed in adulthood, and accounts for 90-95% of all cases.  Risk factors for Type 2 diabetes include a positive family history of the disease, being overweight, physical inactivity, age, ethnicity (African Americans, Hispanics/Latinos, Native Americans, Asian Americans and Pacific Islanders are at particularly high risk), a history of gestational diabetes, pre-diabetes, high blood pressure, and high cholesterol (AOA).
  • Gestational diabetes is glucose intolerance experienced during pregnancy.  It is typically diagnosed during the 2nd or 3rd trimester.
  • Pre-diabetes is a term used to refer to above-normal blood glucose levels that are below the threshold for diagnosing diabetes.  Intervention (ie: healthy diet, physical activity, weight loss) can reduce the rate of conversion from pre-diabetes to diabetes.  In 2012, the CDC found that 37% of Americans 20 years of age and older fell into the pre-diabetes category in 2009-2012 (CDC).

How does diabetes affect the eye?   
  • The most common eye disorder associated with diabetes is diabetic retinopathy.  Diabetic retinopathy is progressive damage to the small blood vessels that supply the tissue lining the inner surface of the eye (the retina).  The AOA has some great videos to help illustrate the disease here.  Diabetic retinopathy is the leading cause of new cases of blindness and low vision in Americans age 20 to 74 (AOA).   In 2005–2008, of adults diabetics 40 years of age or older in the US, 28.5% had diabetic retinopathy, and 4.4% had advanced diabetic retinopathy—with conditions such as clinically significant macular edema and proliferative diabetic retinopathy—that could lead to severe vision loss (CDC).  
Proliferative diabetic retinopathy
    • Non-proliferative diabetic retinopathy (NPDR) occurs when the capillaries of the retina balloon (microaneurysms) due to weakening of the vessel walls.  They may leak blood (hemorrhages) and/or fat deposits (exudates) into the retina.  NPDR is classified in 3 stages- mild, moderate or severe.  No treatment is typically indicated for milder cases, unless there is clinically significant macular edema present.  Frequent monitoring is imperative, as more severe cases may warrant treatment. 
    • Proliferative diabetic retinopathy (PDR) occurs when blood vessels that nourish the retina become blocked, shutting down the blood supply to parts of the retina.  The retina then sends out signals to grow new blood vessels (neovascularization).  These new vessels grow on the surface of the retina and/or into the gel-like substance that fills the back of the eye (the vitreous).  These new vessels are bad news because they have weak, thin walls that can leak blood or cause scar tissue to grow.  PDR has a high risk of vision loss if it is left untreated. Typical treatments may include scatter laser therapy (PRP), injecting medications into the eye (intravitreal injections), and/or removing and replacing the vitreous (vitrectomy).   
    • Macular edema results when the capillary walls weaken and allow fluid to leak into the area of the retina that is responsible for your central, sharpest vision (the macula).  Macular edema can occur at any stage of diabetic retinopathy, and can even be present with 20/20 vision.  Like PDR, macular edema has a high risk of vision loss if it is left untreated.  Treatment for macular edema is typically intravitreal injections, and/or focal laser therapy if needed.  
              Some tools your eye doctor may use to diagnose and evaluate diabetic retinopathy: 
      • Retinal cameras are used to take photographs of the retina (like the one seen above) in order to monitor retinopathy.
      • Optical coherence tomography (OCT) can be used to evaluate how much swelling or edema is present.  An OCT is a scanning laser that can assess the thickness of the retina. 
      • Fluorescein angiography (FA) may be ordered to evaluate leakage and guide treatment.  A dye is injected into a vein in the arm and photos of the retina are taken as the dye reaches the retinal vessels.
  • Other eye disorders associated with diabetes: 
    • A cataract is a clouding of the lens of the eye.  It often develops earlier and progresses more rapidly in diabetics compared to non-diabetics (AOA).  
    • Eye movement disorders can occur secondary to diabetic neuropathy, resulting in double vision.  
    • The optic nerve can also be affected.  There may be swelling (diabetic papillopathy) or damage due to insufficient blood supply (anterior ischemic optic neuropathy) (ADA).
    • Diabetes can also cause blurred vision in the absence of all of the above.  It is believed that high blood glucose levels cause increased fluid absorption in the lens of the eye, thus changing its shape and causing fluctuations in vision.  

How often should a diabetic see their optometrist?  Type 1 diabetics should have a dilated eye exam within 5 years of diagnosis, and at least yearly thereafterType 2 diabetics should have a dilated eye exam upon diagnosis, and at least yearly thereafterYour optometrist may suggest more frequent examinations based on the presence and severity of diabetic eye disease, or they may refer you to a retinal specialist for treatment if indicated.  The strongest predictor of diabetic retinopathy is the duration of diabetes, so it becomes increasingly important for diabetics to have regular eye exams.  Do not wait for symptoms to see your eye doctor!  Early intervention is key.

CliffsNotes: Diabetes is a multi-organ disease, and avoiding its complications takes a life-long commitment.  Yearly dilated eye exams are an important part of that commitment.  

Tuesday, October 28, 2014

Halloween contact lenses

As Halloween approaches, it is important to remember that there are serious risks associated with improper costume contact lens wear.  ALL contact lenses- even decorative lenses that do not provide vision correction- are classified as medical devices, and their safety and effectiveness is overseen by the Food and Drug Administration (FDA).  They need to be properly fit and evaluated by an eye doctor, and thorough contact lens care instructions need be given at that time.

Here are a few tips to minimize the risk associated with decorative contact lens wear:
  1. Get a contact lens exam, fitting, and prescription from a licensed eye doctor. This applies even if the lenses do not correct your vision.  A valid prescription specifies the brand of contact lens and the fitting parameters of that lens.  Contact lenses are NOT one-size-fits-all.    
  2. Purchase contact lenses from a reputable source that is authorized to sell contact lenses (ie: not beauty shops, flea markets, costume stores, etc).  A vendor is required by law to request a current, valid prescription before selling a consumer contact lenses. 
  3. Follow the contact lens care instructions given to you by your eye doctor.
  4. Remove lenses and see your optometrist immediately if you notice any eye redness, discharge, pain, or decreased vision.  Infections related to contact lens wear can be potentially blinding!
CliffsNotes: ALL contact lenses are classified as medical devices by the FDA.  It is unsafe to buy and wear contact lenses without a valid prescription!

Additional recommended resources:

Thursday, September 25, 2014


Inspired by the book Hello, Cupcake!
InfantSEE® is a public health program that is designed to ensure that eye care becomes an integral part of infant wellness care.  If your child is between 6 months and 12 months old, an InfantSEE® provider will perform a one-time comprehensive infant eye assessment at no cost to you.  This allows the opportunity for early detection of risk factors that might lead to potential eye and vision problems.  Many eye conditions do not have signs/symptoms that can be easily identified by a parent or pediatrician.  

The American Optometric Association (AOA) recommends an eye exam at 6 months of age, yet only 18% of parents reported that their infant had received a comprehensive eye exam before age 1, according to the Eye-Q survey conducted by the AOA in 2011.  Vision development has stages, and many development milestones relating to the eye and vision have been reached at 6 months.  Even though some skills reach near-adult levels in infancy, the visual system continues to develop through childhood.

Optometrist rely on patient and family history along with objective testing to determine if a baby has or is at risk for having a vision or eye problem.  Although problems are not common, it is important to identify children who have specific risk factors at this stage.  Vision development and eye health problems can be more easily corrected if treatment is begun early.  There are four main areas that are evaluated during an infant vision and eye assessment:

1.  History:  The optometrist will ask questions relating to the pregnancy, delivery, and development of the child.  Some risk factors for potential eye problems include premature birth, low birth weight, high levels of oxygen therapy, low APGAR scores, and a strong family history of eye problems.

2.  Vision:  Obviously, a baby will not be able to read the letters on the eye chart or tell the optometrist that choice 2 is better than choice 1.  Instead, the optometrist will use objective, non-verbal techniques to estimate the child's visual acuity and refractive error (nearsightedness, farsightedness, astigmatism).  High amounts of refractive error in one or both eyes is a risk factor and will need to be monitored more closely and/or treated to ensure proper visual development.  When these issues are caught and treated early, vision loss in the form of amblyopia can be avoided.  A more detailed description of amblyopia and refractive errors can be found in the back-to-school post.

3.  Eye alignment:  Besides assessing vision, the optometrist will also be checking to see if the infant's eyes are aligned and working together. These skills are not fully developed in the first few weeks of life.  Constant and/or significant eye deviations noted at the InfantSEE® exam may require treatment with glasses/contact lenses or surgery, depending on the type of eye turn.  As mentioned above, these issues need to be addressed early on to ensure proper visual development.   

4.  Ocular health:  The optometrist will use handheld instruments to assess the health and function of the structures of the outer eye.  He/she will also use an eye drop or spray that dilates the baby's pupils to check the health of the inner eye.  

If all is well at the InfantSEE® exam, the next time a child should be seen by their optometrist is at 3 years of age, or sooner if a problem/concern arises.

For more information, and to find an InfantSEE® provider near you, please visit http://www.infantsee.org/.

CliffsNotes: Babies need eye exams too!  

Additional recommended resources:

Friday, August 29, 2014

vision & learning

Not only is August back-to-school time for most kids, but it is also National Children's Vision and Learning month.  I discussed the importance of eye examinations in school-aged children in the previous post.  Here, I will go into a little more detail on how a child's vision and learning are related.

Learning, particularly in the form of reading, requires a combination of many visual skills.  A thorough eye exam is needed to evaluate these skills.
  • Visual acuity refers to the clarity or sharpness of vision.  Typically, distance visual acuity is measured at 20 feet, and near visual acuity is measured at 40 centimeters.  A child can see 20/20 but still have issues with any or all of the skills below.
  • Accomodation, or focusing, refers to the ability to keep things clear at varying distances.  For instance, when a child is copying something from the board to his/her paper, the accomodative system is responsible for shifting focus quickly and easily so as to maintain clear images far away and up close.  If this system is over- or under-worked, it can result in blur, headaches, and/or eyestrain.  Issues with accomodation are typically addressed with appropriately prescribed glasses, or the use of vision therapy to train the system, or a combination of both.    
  • Eye teaming refers to the ability of the eyes to work in tandem to produce a single, fused image with depth.  The most common eye teaming deficiency is called Convergence Insufficiency (CI).  When doing near work, the eyes must converge, or move inwardly.  In CI, a person's eyes tend to rest in an outward position, resulting in an inability to converge normally and comfortably.  People with CI have to exert extra effort to keep the eyes aligned to maintain a clear and single image.  This extra effort can lead to eye strain, headaches, fatigue, difficulty concentrating, and problems with comprehension when doing near work for even a short period of time.  If this extra effort is exhausted, a person with CI may see double (if the eyes drift outward), or the brain may suppress the image from one eye to avoid seeing double.  According to a scientific research study by the National Eye Institute, office-based vision therapy is the most successful treatment for this condition (1).
  • Ocular motor skills are involved in keeping the eyes stabilized on a target, and moving the eyes quickly and accurately from target to target.  The act of reading involves a series of eye movements called saccades and fixations.  Saccades are the eye movements that allow us to quickly redirect our line of sight from one location to another.  When reading, saccades allow us to move through a line of text.  The normal reader averages about 7-9 letter spaces per saccade.  Fixations occur when the eye is relatively still.  Regressions are eye movements in the right-to-left direction that occur when we reread a word or section.  They occur 10-15% of the time in skilled readers.  Less skilled readers typically have longer fixations, shorter saccades, and make more regressions than more skilled readers (2).  When these ocular motor skills are deficient, it can lead to one losing their place when reading, skipping words, and reading slowly.  This is also an area that can be trained with vision therapy.
  • Visual perception has to do with how we process the information we receive through the visual system.  Some sub-categories of visual perception include visual memory (the ability to recall what is seen), visual-motor integration (the ability to coordinate visual input with motor output), visual closure (the ability to identify a form without its full presentation), and visual-spatial skills (the ability to perceive the position of an object relative to oneself and relative to other objects in space).  There will be a separate post in the future with detailed descriptions and examples of each area of visual perception.   
As you might imagine, a deficiency in any of these areas can have negative effects on a child's learning.  A child that sees double, gets headaches, or loses his/her place when he/she reads may have a short attention span and exhibit frustration and disinterest in school.  Because of similarities in the presenting symptoms and signs, some children that are suspected of having learning or behavioral problems may have an undiagnosed visual problem.  Ruling out vision-related issues as an obstacle to success in school is an important piece of the puzzle.

There are many optometrists out there that specialize in this area of optometry.  To find one in your area, go to www.covd.org, or ask your primary care optometrist to recommend one close to you.

CliffsNotes: Vision and learning are very much connected!

Additional recommended resources:

Tuesday, July 29, 2014

back-to-school eye exams

For many parents, the next few weeks will be filled with orientations, school supply lists, sports physicals, and immunizations.  If you are in that boat, be sure to include a visit to your eye doctor to have your child's eyes examined before starting the school year.  Experts estimate that as much as 80% of learning occurs through the visual system (1), so give your child every possible opportunity to succeed in school.  Learning, particularly in the form of reading, requires a combination of many visual skills.  There is far more to vision than just seeing 20/20.  

Vision screenings at the pediatrician's office and at school, though helpful in flagging some potential problems, usually only assess one or two aspects of vision.  Screenings are limited and non-diagnostic, so they are not a substitute for a comprehensive eye exam.  I regularly see kids who pass school screenings but have vision problems that need to be addressed.  Some states actually require a comprehensive eye exam before entering kindergarten, which is a fantastic idea.  The visual system is not fully developed in young children, and equal input from both eyes is necessary for proper development.  The earlier problems are detected, the better the chance of treatment being successful.  The American Optometric Association (AOA) recommends an eye exam at 6 months old, 3 years old, and again before entering first grade.  While in school, a child/teen should have an eye exam at least every 2 years if no issues exist, or yearly if he/she wears glasses or contact lenses.  Depending on the child and the condition, your eye doctor may recommend more frequent examinations.  

Some common signs and symptoms for parents and teachers to keep an eye out for:

  • squinting
  • eye(s) turning in or out
  • sitting close to the TV 
  • holding books close to the face
  • complaining of seeing double
  • complaining of headaches
  • tilting head 
  • avoiding reading and/or reading slowly
  • losing place when reading and/or skipping words
While some children will have symptoms and signs that parents and/or teachers can pick up on, it is not uncommon to find children with issues that do not report any symptoms at all.  That is why the objective tests done during a comprehensive eye exam are so important for young children.    

According to the American Public Health Association, about one in four school-aged children has a vision problem that interferes with learning.  Here is a brief overview of some eye conditions that are relevant to this age group:
  • Hyperopia, myopia, and astigmatism:  These are all types of refractive error.  A refractive error exists when the eye doesn't focus light exactly on the back of the eye (the retina).  An eye doctor measures the refractive error of the eyes and prescribes glasses/contact lenses if needed.  Correcting a child's refractive error when appropriate is the first step in addressing problems with the visual system because it may be the root cause of other vision problems, like those described later in this post.  
    • Hyperopia, or farsightedness, is when the eye focuses light behind the retina.  Small amounts of hyperopia are normal in young children.  Kids can often compensate for this by using their eye muscles to bring images into focus.  But when the amount of hyperopia is substantial, it creates an unnecessary burden on the system and can result in blur, fatigue, eye strain, and headaches, especially when reading.  High amounts of uncorrected hyperopia can cause an inward eye turn to develop as well (accomodative esotropia).  
    • Myopia, or nearsightedness, is when the eye focuses light in front of the retina.  Those with myopia have difficulty seeing far away.  Myopia is often first detected in school-aged children, and typically progresses through the adolescent years.
    • Astigmatism is when the curvature of the cornea and/or the lens of the eye is different in one direction than it is in another, and light gets focused at two different points.  This can cause blur and distortion up close and far away.    
  • Strabismus:  Commonly called crossed eyes, strabismus is a misalignment of one or both eyes, present in 2-5% of the general population.  The eye may turn in (esotropia), out (exotropia), up (hypertropia), or down (hypotropia).  It may happen all the time, or it may happen only some of the time (constant vs. intermittent).  The turned eye may be the same eye all the time, or it may alternate between the two (unilateral vs. alternating).  When the eyes are pointing in two different directions, they are sending the brain two different images.  Depending on the frequency and severity of the eye turn, it may cause double vision.  Alternatively, the brain may learn to ignore the image from the turned eye in an attempt to relieve the confusion.  This adaptation is called suppression.  If left uncorrected, strabismus can result in decreased vision in the turned eye (ambylopia) and loss of depth perception.     
  • Amblyopia:  Sometimes referred to as lazy eye, amblyopia affects 2-3% of the general population.  Amblyopia is defined as reduced vision in one eye, or less commonly both eyes, in the absence of disease or structural abnormalities.  It can be caused by an eye turn (strabismic amblyopia), or a high prescription in one or both eyes that hasn't been corrected (refractive amblyopia), or something physically obstructing the line of sight (deprivation amblyopia).  Amblyopia occurs in the brain during the developmental stage, and it is often a preventable and treatable cause of vision loss.  The sooner it is diagnosed and treated, the better the chance of achieving normal visual function.  This is a big reason why eye exams are recommended early in life. 
  • Ocular motor dysfunction (OMD):  Patients with OMD have problems keeping their eyes on a target (fixation), moving their eyes quickly and accurately from one target to another (saccades), and following a moving target with their eyes (pursuits).  These eye movements play an important role in reading and sports.  OMD usually does not present by itself; a child with OMD may also have issues with focusing and/or eye teaming.  The primary treatment here (assuming the appropriate glasses prescription has been given) is vision therapy.    
Vision therapy is a program of activities designed to help correct deficiencies and improve efficiency of the visual system.  Vision is a developed skill, and thus can be enhanced with guided training.  Vision therapy can be prescribed to help treat some conditions I mentioned above, as well as others relating to focusing and/or eye coordination.  Not all optometrists offer vision therapy, but all optometrists can direct you to one in your area that does provide such services.

CliffsNotes: Be sure to add a comprehensive eye exam to your child's yearly back-to-school checklist.  Clear, comfortable, single vision is important to a child's academic success!

     Additional recommended resources:

(1) Gazzaniga MS, Ivry RB, Jangun CR. Cognitive Neuroscience, the Biology of the Mind. New York, NY; WW Norton & Co, 1998.  

Tuesday, June 17, 2014

summer sun safety

Inspired by the book What's New, Cupcake?

The season that we were all dreaming of during Snowpocalypse has finally arrived!  But with the sweet summer sunshine comes dangerous UV radiation, and it is important to protect yourself from its harmful effects.  

The majority of the sun's energy can be classified as either visible light (that we see), infared radiation (that we feel as heat), and ultraviolet radiation.  Ultraviolet radiation has a shorter wavelength and more energy than visible light.  There are 3 categories of UV rays: UV A, UV B, and UV C.  
  • UV C rays have the shortest wavelength (100-279 nanometers) and the most energy of the three.  We don't hear much about UV C rays because they are, for the most part, blocked by the ozone layer.  
  • UV B rays have a slightly longer wavelength (280-314 nm) and are partially filtered by the ozone layer.  This is the category of UV radiation that is linked to sun burns and skin cancer.  In terms of the eye, most UV B rays are absorbed by the cornea (the clear part of the front of the eye).  
  • UV A rays have the longest wavelength (315-380 nm) of the three.  Though they are lower in energy, UV A rays penetrate the skin more deeply than UV B rays and are thought to contribute to premature skin aging and wrinkling, as well as skin cancer.  Most of the UV radiation that we are exposed to is UV A.  Unlike UV B, UV A rays can pass through the cornea of the eye, potentially causing damage to the lens and retina.    
  • Beyond UV, research is being done on the effects of the sun's high energy visible (HEV) radiation, or blue light.  Some studies suggest there is a possible association between exposure to large amounts of blue light and the development of macular degeneration, a disease in which the tissue of the back of the eye that is responsible for your central vision (the macula) is damaged, thus leading to vision loss.  
How is UV radiation dangerous to your eye health?
  • In the short term, intense exposure to UV radiation while unprotected can cause a condition called photokeratitis.  Also known as snow blindness or UV keratitis, photokeratitis is essentially a sunburn of the eye.  The symptoms usually begin a few hours after exposure, and they include pain, redness, tearing, and light sensitivity.  It is a temporary, but very unpleasant, condition.  
  • The most dangerous effects of UV radiation occur over time.  Because damage from UV radiation is cumulative, it is important to develop good sun safety habits early on in life.  Here are some examples of conditions that are thought to be linked to long-term UV exposure:    
    • A pterygium is a benign growth of the conjunctiva (the tissue covering the white part of the eye) that extends onto the cornea (the clear part).  Surgical removal may be advised if the pterygium interferes with vision.  A pinguecula is a similar finding, but it is confined to the conjunctiva and does not extend onto the cornea.  It appears as a yellow-ish raised nodule on the white of the eye. 
    • Exposure to UV radiation is thought to play a role in accelerated cataract formation (clouding of the lens) and retinal damage.
    • Beyond that, skin cancer can also develop on the eyelids or on the skin around the eyes.  The Skin Cancer Foundation reports that eyelid skin cancer accounts for 5-10% of all cases of skin cancer, with basal cell carcinoma being by far the most common.
Basal cell carcinoma
Here are my top 5 sun safety tips:
  1. Protect the little ones!  Kids spend a lot of time outdoors, and the lenses of their eyes allow more UV radiation through to the back of the eye when compared to adults.  As mentioned before, UV damage is cumulative, so be sure to start protecting the eyes early!  The Vision Council reports that 25% or more of an individual’s lifetime exposure to UV radiation occurs before age 18.  
  2. Check the labels.  Whether you are looking for sunglasses for yourself or your kids, be sure to purchase sunglasses that block 99-100% of UV A and UV B rays.  The darkness of the lens is not an indication of how much UV-blocking action you have, so be sure to check the labels.  The label may read 100% UV protection or UV 400 (meaning it blocks rays shorter than 400nm).  
  3. Talk to your optometrist and optician about your outdoor activities.  There are several options available in terms of prescription sunglasses, so your best bet is to speak with your eye care professional and determine which is best for your lifestyle.  Polarized lenses are designed to reduce glare and reflections off of surfaces like water, snow, or pavement, so they are an especially good choice for boaters, fishers, and skiers.  If you wear prescription glasses, there are coatings that can be placed on the front and back of lenses to block UV radiation and reflections.  Additionallyyou can opt for photochromic lenses (Transitions is a well-known brand) that darken on exposure to UV.  There are clip-on/magnetic sunglasses that can attach to your glasses as well.  So many options!
  4. Contact lenses that block UV radiation are available.  The Food and Drug Administration (FDA) puts UV blocking contact lenses into two classes: Class 1 UV blockers absorb over 90% UV A and over 99% UV B radiation, and Class 2 UV blockers absorb more than 70% of UV A and more than 95% of UV B radiation.  Ask your optometrist about what options are available for you.  Wearing contact lenses that help block UV radiation does not replace the need to wear sunglasses, as contact lenses do not cover the whole eye and do not protect the eyelids.  
  5. Last but not least, wear a wide brim hat to minimize the amount of exposure your eyelids and eyes have to harmful UV radiation.  Wrap-around sunglasses help in this regard too, as they are more fitted to the face and prevent peripheral rays from reaching the eye.  Be sure to take precautions even if it is not particularly sunny outside.  While peak sun hours are between 10am and 2pm, it is believed that the eyes receive the most UV exposure in the hours directly preceding and following this time period, due to the angle of the sun in relation to the eyes.      
CliffsNotes: UV radiation is bad.  Wear sunglasses, a hat, and sunscreen.  

Enjoy the summer season safely!

Monday, May 26, 2014

healthy vision month

May is Healthy Vision Month (nei.nih.gov/hvm)!  Yes, I realize May is almost over.  In my defense, I wrote most of this article a couple of weeks ago.  It just took so long to post because I couldn't decide on fonts for the blog...

Even though I was visiting the eye doctor fairly regularly as a child and a teenager, I didn't really have a clue what was being done during the exam or why it was being done until I began looking into optometry as a career.  I think it's important to know at least a little about what your eyes do, how they work, and why it's important to get them checked regularly.  I will try not to bore you too much and just hit the high points!
  • On the most obvious level, your eyes allow you to see the world around you.  The goal is to have clear, comfortable, and single vision.  Eye doctors have multiple tools they can utilize to achieve this goal, such as glasses, contact lenses, vision therapy, and surgery.  But "seeing well" is only a piece of the puzzle and is not an indication of your eye health.
  • Aside from revealing signs of eye infections, glaucoma, cataracts, and macular degeneration, your eye exam can also reveal general health problems.  Your eyes are connected to the rest of your body, so conditions that affect your body can manifest in the eyes.  The eyes are the only place in the body where your blood vessels can be viewed directly and non-invasively.  Through a dilated eye exam, your eye doctor can examine the blood vessels and tissue of the back of the eye (the retina), which can reveal signs of systemic conditions such as diabetes, hypertension, anemia, cardiovascular disease, and more.  Some of these conditions can present with no symptoms early on, so it is important to see your eye doctor regularly.
photo of the back of the eye
  • Your eyes are an extension of your brain.  Visual processing begins at the retina of the eye and ends at the visual cortex of the brain.  Many aspects of an eye exam evaluate the state of the visual pathway, including pupil testing, visual fields, extra-ocular motility testing, and fundus examination.  These tests can uncover central nervous system issues such as multiple sclerosis, brain tumors, increased intracranial pressure, brain aneurysms and more.  

So now that we've covered why you need an eye exam, let's discuss how often you should have an eye exam.  
  • ADULTS:  The American Optometric Association (AOA) recommends that asymptomatic/risk-free adults have an eye exam at least every 2 years until age 60, and every year thereafter.  Adults “at risk” are recommended to have eye exams every 1-2 years, or as deemed appropriate by their eye care professional.  Many of us fit into the “at risk” category, as that includes people who wear contact lenses, people with a family history of eye diseases like glaucoma or macular degeneration, people working in occupations with high visual demands or eye hazards, and people with diabetes, high blood pressure, or other vascular abnormalities.  I personally recommend a comprehensive eye exam at least every year for most patients, but it's particularly advised if you fall into this group.  
  • CHILDREN:  The AOA recommends an eye exam at 6 months old, 3 years old, before first grade, and every two years after that for asymptomatic/risk-free children.  As with adults, the recommended frequency of examination increases if the child is “at risk,” which can include those children born premature, those with developmental delays, those with eye turns, and those with a high prescription in one or both eyes.  While vision screenings at school and at the pediatrician's office are incredibly valuable tools, they do not replace comprehensive eye exams.  I cannot stress enough the importance of getting children to the eye doctor early.  The sooner things like eye turns and high prescriptions can be detected, the better the visual prognosis for the child.  I will dedicate a separate post to children's eye health in the future.

I hope this post gave you some insight into eye examinations and why they are an important part of your health care.  As always, feel free to email me with any questions, comments, or concerns.  Thanks for visiting, and I hope you continue to follow the blog!

Sunday, May 18, 2014


Hello and welcome to Eyecing on the Cake!  This is simply a fun and educational blog about vision and eye health, with some adventures in cupcake baking sprinkled in as well.  For more background information about this blog, check out the Introduction page.  If you are interested, please consider signing up to receive email notifications when the blog is updated (see the "Follow by Email" area on the right side of this page).  Or "Like" our Facebook page (the icon on the right will direct you to our Facebook page).

Thanks for visiting!