Waverley Eye Care Centre

Optic Nerve Head Drusen

Signs and Symptoms
A condition involving retained hyaline bodies in the anterior optic nerve, optic nerve head drusen (ONHD) has been referred to in the literature by many diverse and confusing names. Among the descriptive terms are congenitally elevated or anomalous discs, pseudopapilledema, pseudoneuritis, buried disc drusen, and disc hyaline bodies. ONHD is encountered in approximately 1 percent of the general population, and is bilateral in 70 percent of cases. The condition occurs primarily in Caucasians and is believed to demonstrate an autosomal dominant inheritance pattern with incomplete penetrance. Typically, patients with ONHD remain asymptomatic, and the finding is discovered only on routine ocular evaluation. In some instances, however, the condition can present with mildly decreased visual acuity and visual field defects. An afferent pupillary defect may be noted if the condition is both significant and asymmetric. Reports of recurrent, transient visual obscurations associated with disc drusen have also been documented.

The classic appearance of ONHD involves bilaterally elevated optic discs with irregular or "scalloped" margins, a small or nonexistent cup, and unusual vascular branching patterns that arise from a central vessel core. Often there are small, refractile hyaline deposits visible on the surface of the disc and/or in the peripapillary area. ONHD most often manifests on the nasal disc margin, but can be found within any part of the nerve head. In younger patients, the disc elevation tends to be more pronounced and the drusen less calcific, making them less visible ophthalmoscopically, and hence offering a more challenging diagnostic dilemma. Unlike true disc edema, ONHD very rarely presents with juxtapapillary nerve fiber edema, exudate, or cotton-wool spots.

Pathophysiology
There is no histopathological correlation between drusen of the optic nerve head and retinal drusen; the former represent acellular laminated concretions, often partially calcified, possibly related to accumulation of axoplasmic derivatives of degenerating retinal nerve fibers. As mentioned, ONHD tend to remain "buried" in children, but slowly become visible as they enlarge toward the disc surface and as the overlying retinal nerve fiber layer progressively thins. They are usually ophthalmoscopically detectable by the early to mid-teens, although these authors have seen patients in their mid-20s who continue to display "buried drusen". Within the optic nerve, the hyaline bodies are confined anterior to the lamina cribosa and thus can compress and compromise the nerve fibers and vascular supply, leading to visual field defects and disc hemorrhages. Along with slowly developing optic atrophy in extreme cases, disruption of the juxtapapillary tissue can result in choroidal neovascular membrane formation leading to subretinal hemorrhage and disciform retinal scarring.

Management
Although ONHD is typically classified as a benign condition, it can lead to modest visual compromise. First and foremost, ONHD must be clearly differentiated from acquired disc edema, which warrants immediate neurologic evaluation and treatment. Management of ONHD includes prompt and proper diagnosis, which is aided greatly by the use of ocular ultrasonography. The high reflectivity of the calcified hyaline bodies is dramatically evident on B-scan ultrasonography, even at particularly low gain levels. Careful evaluation of optic nerve function is imperative, and should include standard Snellen acuity, contrast sensitivity, color vision testing, and threshold visual fields. Photodocumentation should be obtained for future monitoring. It is also important for patients to self-monitor their vision periodically, particularly because of the risk of choroidal neovascular membrane formation. Should these membranes be noted or suspected, intravenous fluorescein angiography is recommended, followed by laser photocoagulation as indicated. More routine cases should be monitored every six to 12 months.

Michael D. Nelson, OD

LindenWoods Fall Classic 2009

LindenWoods Fall Classic 2009

Waverley Eye Care is proud to again sponsor the LindenWoods Fall Classic.

This year we have included 137 peel and win postcards in the participant bags.  Below are the odds of winning.  Prizes have no cash value.

Skill testing question:  Amblyopia affects about ____% of the population.   Click here for the answer.

• 1:69 Free Sleeve of Golf Balls
• 1:69 25% Off Purchase of Lenses
• 1:69 $50 Off Purchase of Bolle or Adidas Sunglasses
• 1:35 $75 off Nikon Presio Power Progressive Lenses
• 1:34  Complimentary Adult Eye Exam ($65 value)
• 1:34 Complimentary Optomap Retinal Photo ($45 value)
• 1:23 Free Nikon Ice Coating
• 1:17 Free Contact Lenses Training/Fitting
• 1:11 $30 off Bolle Sunglasses
• 1:8    Free Antireflection Lens Spray
• 1:5    10% Off Purchase of Frame and Lenses
• 1:3    10% Off Purchase of Frame

Contact Lens Prices

A patient came in yesterday and gave my staff a long talk on how his soft contacts were so much cheaper at Costco.  He was quite loud and was so emphatic I thought I better check into this because we work hard to make sure that our prices are very competitive at Waverley Eye Care.  So I called Costco and asked what their price is:

Oasys for Astigmatism:

Costco:  6 month supply: $178.00 - $20 mail in rebate = $158.00

1 year supply: $356.00 - $50 mail in rebate = $306.00

Waverley Eye Care: 6 month supply: $180.00 -$20 mail in rebate = $160.00

1 year supply: $340.00 - $50 mail in rebate = $290.00

Obviously our prices are extremely competitive,  and this is not even taking into consideration things like us providing free replacement of ripped or torn lenses and including contact lens checks with an eye doctor at no charge.  What is also obvious is that we need to educate our patients' better on what a good value we can offer them, we will try harder.

Michael D. Nelson, Optometrist

Choroidal Nevus

  Choroidal nevi are commonly found in the choroid, a blood vessel-rich layer lying between the retina and the sclera. Although they are not necessarily a "normal" finding in our eyes, they are quite common and may not represent anything wrong with the eye. Choroidal nevi are present in about 6% of eyes.  Nevi vary from patient to patient but most look very similar and have certain traits that eye doctors are very familiar with.  Choroidal nevi are not usually harmful. However, just like a freckle on your skin, it should be monitored for changes in color, size or shape.  Typical treatment involves taking a digital photograph for documentation.  

A choroidal nevus is the name given to a spot, freckle or mole that appears inside the eye. 

 

Choriodal nevi are benign, however, we want to watch closely for the rare development of a choroidal melanoma, a tumor found in the eye. It is estimated that about 1 in 8000 of choroidaI nevi will transform into melanomas. Choroidal melanomas are malignant tumors and due to their aggresive nature that can sometimes result in death, they must be treated early.

More information is available at:  The Eye Cancer Network

Michael D. Nelson

Ocular Dominance

Ocular domiance is when the brain prefers input from one eye compared to the other.  Generally the brain takes the images from each individual eye and merges them into one image.  However, because the eyes are not located in the same location there are times that if the brain tried to merge the images from the two eyes you would actually see double.  In these situations the brain will suppress the signal from the non-dominant eye and focus on only the dominant eye.  This suppression of the non-dominant eye will usually occur when someone is aiming or trying to ‘sight a line’ 

Eye dominance s similar to being right or left handed but is it not same as your handedness.  About two-thirds of the population is right-eye dominant, however in some people neither eye is dominant.  Eye domiance can change temporarily depending on the direction of gaze or the size of the image someone is looking at.

Eye domiance can be factor in some aiming sports like darts or archery.  It is also an important factor in patients who have monovision as a result of contacts or refractive surgery.

There a number of ways to determine eye dominace but an easy way is the Miles Test. 

 

As shown in the picture, hold your hands out at arms length and with both eyes open, look through the hole formed by your hands at a distant object. Keeping that object in view, slowly move your hands towards your face until they touch your face. The hole formed by your hands should be over one of your eyes. This eye is your dominant eye and will control your aiming. Another quick way to test your eye dominance is to point your index finger at a distant object with both eyes open, then close one eye and see if your finger appears to move away from what you are pointing at. If your finger does appear to move, then the eye that you closed is your dominant eye. Try again with your other eye and your finger should not appear to move.

Michael D. Nelson, OD

Amblyopia

 

 

Amblyopia is a disorder of the visual system that is characterized by poor or indistinct vision in one or both eyes that is otherwise physically normal.  The brain and the eye work together to produced vision:  Light enters the eye and is focused on the retina.  The retina changes light into nerve signals that travel along the optic nerve to the brain (visual cortex).  The medical term for the brain not working properly is amblyopia.  The eye itself looks normal, but the brain does not interpret normal vision.  Putting on glasses (without treatment) will not produce 20/20 vision.

 

How common is amblyopia?

Amblyopia is the most common cause of visual impairment in childhood.  It affects about 5% of the population.  Unless it is successfully treated in early childhood, amblyopia persists into adulthood, and is the most common cause of monocular (one eye) visual impairment.

 

What causes amblyopia?

Amblyopia may be caused by any condition that affects normal visual development or use of the eyes.  Amblyopia can be caused by:

• Strabismus, an imbalance in the positioning of the two eyes
• Excessive farsightedness or astigmatism
• Unequal prescription between the two eyes
• Opacities such as cataracts

 

How is amblyopia treated in children?

Treating amblyopia involves making the child’s brain use the eye(s) with the reduced vision.  The best outcome is achieved if treatment is started before the age of five.  Currently, there are two ways used to do this:

• Glasses (correcting the optical defect)

This is treatment of hyperopia, myopia, and/or astigmatism through the use of full-time glasses.  This stimulates vision development in the brain.

• Occulusion (patching)

An opaque patch is worn over the stronger eye for months to a year, forcing the brain to use the amblyopic eye.  Patching forces the brain to use the visual cortex designated to the weaker eye to develop normal vision.

 

  

More than you ever wanted to know about Amblyopia:

 

Physiology:

Amblyopia is a developmental problem in the brain; the part of the brain corresponding to the visual system from the affected eye is not stimulated properly, and develops abnormally.  This has been confirmed via direct brain examination.  David H. Hubal and Torsten Wiesel won the Nobel Prize in Physiology or Medicine in 1981 for their work demonstrating the irreversible damage to ocular dominance columns produced in kittens by sufficient visual deprivation during the so-called “critical period”. The maximum critical period in humans is from birth to two years old.  The problem is caused by either no transmission or poor transmission of the visual image to the brain for a sustained period of dysfunction during early childhood.  Amblyopia often affects one eye, but it is possible to be amblyopic in both eyes if both are similarly deprived of a good, clear visual image.  Detecting the condition in early childhood increases the chance of successful treatment.

 

Symptoms:

Many people with amblyopia, especially those who are only mildly so, are not even aware they have the condition until tested at older ages.  Amblyopes even after being treated to 20/20 may suffer from poor spatial acuity, low sensitivity to contrast and some “higher level” deficits to vision such as reduced sensitivity to motion.  These deficits are usually specific to the amblyopic eye, not the unaffected “fellow” eye.  Amblyopes also suffer from problems of binocular vision such as limited stereoscopic depth perception and usually have difficulty seeing the three-dimensional images in hidden stereoscopic displays such as autostereograms.  However, perception of depth form the monocular cues such as size, perspective and motion parallax is normal.

 

My Story: (since many patients ask)

At 5 months of age, my mother noticed occasionally that one of my eyes was slow to follow.  The first 4 doctors told her she was an uptight first time mother.  The fifth doctor said, yes one eye was more farsighted and had astigmatism.  My mother often questioned the eye doctor, since I was reading at age 3, why I needed to come back every 3 months to monitor the vision.  Since I had to wear the heavy glass lenses in the 1970’s, I now hold back and prescribe glasses reluctantly.  Still today, both my parents, my younger sisters, and all 3 kids see better than 20/20 without glasses.  My oldest daughter slipped from 1 line better than 20/20 down to 20/20 so we did glasses at age 4; one hour a day for one month and she returned to 20/15.

 

National Eye Institute-Supported Research

A Randomized Trial Comparing Part-Time (6 hours a day) Versus Minimal-time Patching (2 hours a day) for Moderate Amblyopia was conducted to determine whether the visual acuity improvement obtaining with part-time patching is equivalent to the visual acuity improvement obtained with minimal patching for moderate amblyopia.  Recend findings show that patching the unaffected eye of children with moderate amblyopia for two hours daily works as well as patching the eye for six hours when combined with a minimum of 30 minutes of near work.  Shorter patching time should lead to better compliance with treatment and improved quality of life for children with amblyopia.  Watching TV, playing video games, or using the computer did not enhance visual development but worked well as rewards to wearing a patch.  Thirty minutes of near work can include reading books, puzzles, colouring, crafts, mazes.

  

Dr. Selena Friesen

Christmas Gift Eye-deas

1.  A Contact Lens Fitting:  $60.00

2.  Bolle Sunglasses $120.00

3.  D&G Frame  $299.00

4.  Paperweight Magnifier $60.00

5.  Checkwriting Guide $19.00

6.  Lens Spray and Cloth $5.00

7.  15 Pairs of Coloured Daily Disposable contacts $50.00

Spectacle Lens Prices

Recently we had a patient inquire about our lens prices and coating warranties, so I did some price comparisons on a High index 1.6 Single Vision Lenses with Antireflection and Scratch Coating in my exsiting frame.

Pearle Vision:  $369 for Generic Brand lenses.  They do not provide any warranty on these lenses.

Hakim Optical:  $219 for Generic Brand lenses with 1 year warranty.

Waverley Eye Care:     $149 for Generic Brand lenses with 1 year warranty.

                                  $229 for Premium Nikon lenses with 2 year warranty.

Michael D. Nelson, OD 

Myopia and Month of Birth

Recently a researcher out of Tel Aviv University's Goldschleger Eye Research Institute studied 300,000 children, examining the association of nearsightedness with thier month of birth.

They found that those born in June or July have a 24 per cent greater chance of becoming severely myopic(> -6.00), than those born in December or January.

"Such findings might suggest that the amount of light exposure generates a biological signal that can influence the emmetropization process [the stage of life when the length of the eye and its focal ability are balanced out]," the study's author said.

The authors stress that myopia can be caused by other factors — such as genetics —and that only 2.2 per cent to 5.6 per cent of severe myopia can be attributed to the season of birth or perinatal light.

So what does this mean to me - well I was born in May and I am only mildy myopic (-1.75).  A quick mental poll of our staff and we have only one staff who was born in June & July and interestingly she is over -6.00. 

So what should you do?  The theory is that it is the increased amount of light in the summer months that may stimulate the development of severe myopia in 5% of the population.  So I would recommend ensuring your summer newborn has adequate protection(sunglasses, hats, shade) from bright sun in those first few months.   

Michael D. Nelson, OD

Myopia/Nearsightedness

NEARSIGHTEDNESS

Nearsightedness, or myopia, as it is medically termed, is a vision condition in which near objects are seen clearly, but distant objects do not come into proper focus.  It occurs when your eyeball is too long or the cornea has too much curvature, and light entering the eye is not focused properly. Some evidence supports the theory that nearsightedness is hereditary. There is some evidence that nearsightedness may also be caused by the stress of too much close vision work.

Nearsightedness is a very common vision condition that affects nearly 30 percent of the Canadian population. It normally develops in school age children. Since the eyes continue to grow during childhood, nearsightedness usually occurs before the individual reaches the age of 20.

You may need glasses part-time or full-time to enable you to see more clearly. If your condition warrants, your Doctor of Optometry will prescribe corrective lenses for you. You may only need them for certain activities, like watching television, going to a movie or driving a car.

Eyeglasses or contact lenses optically correct the problem by altering the way the light images enter your eyes, but they do not cure nearsightedness. At present there are no proven cures for nearsightedness. Surgical procedures such as LASIK and/or ocular implants may eliminate your need for glasses.

Michael D. Nelson