Eye on Vision March 2016

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PV Launches Newly Redesigned Web Site There is an old saying that if something is not broken, don’t fix it. At Precision Vision, we are proud to say that if something is not broken, make it even better.

Importance of Vision in Childhood Development

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Importance of Vision in Childhood Development   Up to the age of 12, children obtain 80% of their knowledge through visual learning.1 This includes activities like reading, writing, viewing diagrams, films and images, and generally interacting with their surroundings. According the American Optometric Association, vision conditions are associated with a child’s inability to master vital … Continue reading Importance of Vision in Childhood Development

Illinois Vision Screening Guidelines

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  Illinois Department of Public Health: Vision Screening Guidelines   Students   The State of Illinois requires annual vision screening be provided for the following students:   All preschool children ages 3 and up All children in kindergarten All children in second grade All children in eight grade All children in special education classes All … Continue reading Illinois Vision Screening Guidelines

Common Early Vision Conditions

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  Common Early Vision Conditions   National ophthalmology surveys suggest that up to 25% of all school-aged children have vision conditions1, a rate that affects millions of children in the United States. Below are the vision conditions that most commonly after preschool and school-age children.   Strabismus   Strabismus is the general term for misalignment of the eyes. … Continue reading Common Early Vision Conditions

Precision Vision Early Detection

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  BACK-TO-SCHOOL: Early Detection Vision Screening Extensive research has proven that maintaining healthy vision and detection of vision conditions – early in the school year and early in life –supports proper physical, intellectual, social and kinesthetic development in all children.   Get Illinois’ future off to the right start! Designed specically for Illinois K-5 students, the Precision … Continue reading Precision Vision Early Detection

Contrast Tests

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Of the three aspects of visual functioning: visual acuity, visual field and contrast sensitivity, the last one receives far less attention in routine medical practice than the other two. Why is this? One of the reasons may be that there are few if any therapeutic decisions that depend on contrast sensitivity. In a busy practice … Continue reading Contrast Tests

500 Shades of Grey?

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Lately, a certain Fifty Shades of Grey has gotten the lion’s share of attention in the media and in popular culture, but did you know the human eye can in fact distinguish as many as 500 different shades of grey? At Precision Vision, we are obsessed with shades of grey – but in a healthy … Continue reading 500 Shades of Grey?

The Radner Reading Chart; a Highly Standardized Multilingual Reading System

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As the trusted leader in the production and development of vision testing devices Precision Vision scourers the world in search of quality vision testing tools developed by industry icons. The Radner Reading Charts are a perfect example of just this type of collaboration. It has long been believed that visual acuity tests are poor predictors … Continue reading The Radner Reading Chart; a Highly Standardized Multilingual Reading System

Patti Pics™ Vision Testing System

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  Patti Pics™ Vision Testing System Patti Pics™ were introduced in 2003 as an improved test for vision screening and testing of pediatric and adult patients where universal symbols and matching may serve the process better than letters or other symbols. They were developed following the Snellen principal of 1862, the recommended standard for optotype … Continue reading Patti Pics™ Vision Testing System

Snellen Eye Test Charts Interpretation

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Snellen designed his optotypes on a 5×5 grid, on which the line thickness is one unit and the letter width and height are five units.  This system is followed for most letter and number charts. For children’s tests (such as Allen pictures and other test symbols), it is often abandoned and much thinner lines are used. Precision Vision … Continue reading Snellen Eye Test Charts Interpretation

Measuring Snellen Visual Acuity

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Measuring Snellen Visual Acuity When Dr. Herman Snellen developed the famous, ground-breaking Snellen visual acuity test in 1862, he launched a defining movement in the vision testing field that would be followed by eye care practitioners to this day. Snellen’s innovations were critical. For his Snellen eye test,the Dutch ophthalmologist did not use the prevailing type fonts of the mid-1800s. Those … Continue reading Measuring Snellen Visual Acuity

Snellen Eye Chart – a Description and Explanation (2)

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Snellen Eye Chart Snapshot What Dr. Herman Snellen did for the field of vision testing is comparable to what the first automobile engineers did to revolutionize the car industry. These pioneers saw a need for change and additional resources at a time when people were yearning for better quality and higher standards of living in … Continue reading Snellen Eye Chart – a Description and Explanation (2)

Snellen Eye Chart – a Description and Explanation

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Snellen Eye Chart Snapshot What Dr. Herman Snellen did for the field of vision testing is comparable to what the first automobile engineers did to revolutionize the car industry. These pioneers saw a need for change and additional resources at a time when people were yearning for better quality and higher standards of living in … Continue reading Snellen Eye Chart – a Description and Explanation

Introduction to Visual Acuity Measurement

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by August Colenbrander, MD – San Francisco Since the 1970’s Precision Vision has built a reputation of producing the most accurate and most durable vision testing tools available.  In the 1980’s they printed the first ETDRS cards and produced the standard ETDRS illuminator cabinet.  Since the early 1990’s they have carried a variety of Low Vision and pediatric testing tools. This … Continue reading Introduction to Visual Acuity Measurement

A – Visual Acuity

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Frequently Asked Questions: What is visual acuity?  What are its limitations? What are visual acuity tests used for? How is visual acuity defined and recorded? What is the reference standard? What should be the measurement steps? What is the Preferred Numbers series? How can I convert between different notations? How can I compare and average … Continue reading A – Visual Acuity

B – Letter Chart Measurements

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A variety of factors need to be considered for accurate measurement of letter chart acuity.  This outline discusses the most important ones. Frequently Asked Questions: What is the preferred chart layout?  What should the viewing distance be? What should the illumination be? What symbols should be used? What display method should be used? What is … Continue reading B – Letter Chart Measurements

C – Near Vision and Reading

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Frequently Asked Questions: Visual Functions and Functional Vision Why should I use a reading test? How can I judge the imaging range of various presbyopia corrections? What is the best print size notation for Reading tests? What is the best layout for Reading tests? Visual Functions and Functional Vision At this point we need to … Continue reading C – Near Vision and Reading

D – Contrast Sensitivity

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Frequently Asked Questions: What is contrast sensitivity, why is it important? What is the Contrast Sensitivity Curve? What are the Colenbrander Mixed Contrast cards? What is contrast sensitivity, why is it important? Visual acuity measures the ability to recognize small objects with high contrast.  Often however, the visibility of objects in our environment is limited … Continue reading D – Contrast Sensitivity

E – Low Vision Tests

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Frequently Asked Questions: What is Low Vision? How do we categorize Low Vision? How do we measure letter chart acuity for low vision patients? How do we measure reading acuity for low vision patients? How do I use the Modified Snellen Formula for reading tests? What is Low Vision? Low vision is not a single … Continue reading E – Low Vision Tests

F – Pediatric Tests

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Frequently Asked Questions: What symbols should be used? What is the effect of “crowding”? What is the preferred distance? Behavioral tests (preferential looking) What symbols should be used? Recognition of letters and numbers is not trivially easy for young children.  Using these symbols may underestimate their acuity by measuring a combination of acuity and cognitive development. A simplified chart … Continue reading F – Pediatric Tests

The Jaeger Notation Debate

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To Jaeger or Not to Jaeger, That is the Question When Jaeger published his notation print samples in 1856 little did he know that they would cause a debate that still generates differing views today. In this article we present the views against the use of Jaeger notations as written by world renowned Low Vision … Continue reading The Jaeger Notation Debate