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Low Plus Reading Glasses 

Developmental optometrists frequently use low plus prescriptions to enhance near vision performance. These glasses, often referred to as performance glasses, differ from conventionally prescribed lenses in that they are not designed to improve visual acuity alone. Studies show numerous benefits from the application of low plus powered lenses at near, including improvements in child behaviour, reading comprehension and speed, and overall visual comfort and efficiency. Developmental optometrists also employ plus at near to aid in slowing the progression of myopia, especially in those with an esophoric (inward) eye position at near. 

Performance glasses differ from conventional corrective lenses. Although the lenses look the same, their functionalities differ. Typical corrective lenses are prescribed to address refractive conditions such as myopia, hyperopia and/or astigmatism. These prescriptions are based on the patient's visual acuity - their ability to see 20/20 on the eye chart. But, good vision is so much more than just being able to see 20/20. Complex visual skills such as eye teaming (vergence), focusing (accommodation) and tracking make up, in part, an individual's functional vision, and should be taken into account when determining their prescription. Developmental optometrists routinely assess functional vision with dynamic testing - determining if a certain lens improves the patient's ability to process visual information - during a routine eye examination. During the exam, the patient may be asked to read, view different targets or track objects while wearing the lenses. Performance lenses, especially when used in conjunction with vision therapy, can help patients improve their visual skills, not just their visual acuity. In terms of making these lenses, of course all prescription lenses have to meet accuracy standards, but since even a small change in lens power can make a significant difference in a patient's visual function, performance lenses require a high level of accuracy when being made. 

The benefits of wearing low powered plus lenses for near work have been studied for decades. A few examples of studies are listed below.
A 1980's study by Larabee and Jones looked at how the application of low plus lenses improved performance at a child's near working distance. Positive behavioural changes were also associated with wearing these lenses while performing near tasks. 
In 1990, a study by Greenspan found a significant improvement in overall visual efficiency when using low plus lenses, including the use of more visually appropriate working distances and improved overall performance of near tasks. 
Iyer and Harris in 2013 found that low plus lenses created an improvement in reading comprehension and speed. 

Low plus powered lenses at near have been associated with slowing the progression of myopia and developmental optometrists routinely prescribe performance lenses to patients showing signs of visual stress at near in attempts to retard the cycle of myopia.
Our modern culture places a strong emphasis on near work. We spend much of our time indoors reading and working on our computers and smartphones. But this is contrary to how our ancestors lived - spending the vast majority of their days moving around outdoors with varied working distances - and contrary to how our visual processing system was designed to be used. Our near visual demands today cause considerable amounts of stress on the visual system and may lead to myopia as the visual system adapts to this high level of stress. Although myopia is classified as blurry distance vision, the process of becoming myopic is a cycle which begins with abnormalities at near before complaints of distance blur begin. Visual stress from prolonged near work is a catalyst for this cycle. When a developmental optometrist is able to pinpoint these anomalous near findings, and intervene at the earliest stages of the cycle, he/she may be able to prevent or minimize the progression of myopia by helping the individual create a more flexible visual system. By using low plus lenses at near, the visual system can relax under the visual stress caused by the prolonged near work and minimize the chance of that individual moving further into the cycle of myopia and propagating it. This method has the greatest effect in cases where accommodative (focusing) excess and esophoria (inward deviation of the eyes) at near are evident. An esophoric eye posture at near will induce a lag of accommodation (ie, the eyes are focused at a point behind the plane of the object instead of directly on it) and the accompanying source of blur will be a driving force for myopia. On the other side of the spectrum, exophoria (outward deviation of the eyes) at near results in a lead of accommodation and subsequent accommodative spasm which can propagate myopia. Adding a low plus prescription at near in these cases will help pull back the accommodative lead into a normal level of accommodative lag.  Evidence supports the practice by developmental optometrists to prescribe low plus lenses at near in cases of esophoria and exophoria at near to aid in slowing down myopia progression. 

Performance lenses are becoming more and more common as individuals (adults and children alike) are spending more and more time on computers, tablets and smartphones and as children are being taught to read at younger ages than ever before. 
We look forward to seeing you and your family members in our office to determine if performance glasses may help you to achieve a more effective and efficient functional visual system. 
Dr. Fink and Jennifer Braniff attended the 2017 International Concussion Summit in Niagara Falls earlier this month to present information to educators and other professionals on the connection between concussions and vision. It was a successful and fun event!
Dr. Ha and Dr. Fink are mentors for optometrists looking to achieve their fellowship certification in vision development and vision therapy through the College of Optometrists in Vision Development (COVD). Both are fellows themselves, and this year they mentored three developmental optometrists from Ontario to attain their board certification.
Congratulations to Dr. Breanne Facey, Dr. Michelle McKenzie and Dr. Chris Schell who all passed their oral examinations in Jacksonville FL last month and are now officially Fellows of COVD! Canada now has 30 FCOVD doctors and it is exciting to see vision therapy grow and thrive here!
 
Dr. Anjali Pathak and vision therapist Vonita attended the Family Wellness Night at John William Boich Public School earlier this month. This free event was open to the general public and featured workshops, information tables and vendor booths on topics ranging from mindfulness and mental health, to family fitness and food preparation. Dr. Pathak and Vonita shared information on the connection between vision and learning, as well as the Eye See Eye Learn program. 
Copyright © 2017 Halton Vision Therapy Center, All rights reserved.


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