Eye Examination Tools
Steven

The phoropter is used to find a person's refractive error. A person usually looks at the letter chart and says whether one or two is better during use.  By the end of use the optometrist would use this information to find a prescription for the patient.
The phoropter is used to find a person's refractive error. A person usually looks at the letter chart and says whether one or two is better during use. By the end of use the optometrist would use this information to find a prescription for the patient.

An ophthalmoscope is a tool used by optometrists to see the eye.  They will mainly focus on the retina and optic nerve. There are two types of this tool, a direct ophthalmoscope, and an indirect ophthalmoscope.
An ophthalmoscope is a tool used by optometrists to see the eye. They will mainly focus on the retina and optic nerve. There are two types of this tool, a direct ophthalmoscope, and an indirect ophthalmoscope.
What are they?

Many eye examination tools are used to test your sight in an eye exam. The two most common though are the phoropter and the ophthalmoscope (Bedinghaus, 2009, p.1).[1] These tools are used to find a prescription if needed for your eyes. The phoropter is used to refract light into your eyes, while the ophthalmoscope shows an image of your eye to the optometrist. The image will mainly show the retina and the optic nerve(MedTerms, 2012, p.1).[2] While using the phoropter you would look at the letter chart (below) and see which lens you can see better with.


This is the eye exam chart you would like at while using a phoropter.
This is the eye exam chart you would like at while using a phoropter.



























1.0 Phoropter

These are some pictures of where light can posibly go in your eye.  There is one right to the back of the eye.  Two past the back and one in the middle of the eye.
These are some pictures of where light can posibly go in your eye. There is one right to the back of the eye. Two past the back and one in the middle of the eye.
The Phoropter is one of the most commonly used eye examination tools (Bedinghaus, 2009, p. 1)[3] . It is used to test a persons refractive error. If a persons refractive error is off they will need glasses (Bedinghaus, 2009, p. 1)[4] . Sometimes the focal point will be too close, too far back or just slightly off, this all changes the prescription given. Light should refract to the retina in your eye. If it does not you would be either near or far sighted. (Heiting, 2010, p. 1)[5] . Phoropters can be used to look for astigmatism in a patients eye. Astigmatism is not a disease but more the shape of the cornea. This is what optometrists look for in eye examinations. Astigmatism is a refractive error which the phoropter can diagnose with the many lenses it uses (Rockwell, 2010, p. 1)[6] .









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2.0 Ophthalmoscope
This is the image of the eye you would see through an ophthalmoscope.
This is the image of the eye you would see through an ophthalmoscope.


An ophthalmoscope is used to see an image of the patient's eye. Optometrists can be looking at the retina and optic nerve (Dictionary, 2012, p. 1)[7] . Possible diseases are also looked for such as glaucoma or even detect why someone may be having headaches ( Glaucoma, 2012, p. 1) [8] . Ophthalmoscopes produce an image of the eye. There are two different types of ophthalmoscopes used for different purposes. There is a direct ophthalmoscope and an indirect ophthalmoscope. The indirect ophthalmoscope gives the optometrist a better view because there are three elements going into the eye instead of just one from a direct ophthalmoscope. With the three elements going into the eye it produces a three dimensional image for the optometrist so they can get a better view of the eye and give a better exam. This means that direct ophthalmoscopes are for more routine check-ups while an indirect ophthalmoscope is used when looking for a disease in the eye or just better performance ( Veatch, 2012, p. 1)[9]




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2.1 Direct Ophthalmoscope

This is a direct ophthalmoscope.  It is held right up to the patient's eye.
This is a direct ophthalmoscope. It is held right up to the patient's eye.

A direct ophthalmoscope is a different type of ophthalmoscope that allows a less detailed picture than the indirect ophthalmoscope. There is a wide range of lenses, that range from +44D to -45D (Opthalmologyweb, 2012, p. 1)[10] . The direct ophthalmoscope magnifies the image and keeps the image upright. The magnification is about 15 times giving a very enlarged image to the optometrist (Medical Dicitonary, 2007, p. 1)[11] . The test would be done in a darkened room to get the best image. The examiner looks for changes in the color or pigment of the fundus, or changes in the shape of blood vessels. (Medical-Dictionary, 2007, p. 1)[12] Also, there can also be different colour filters to find certain problems with the eye. A red free filter can help with the examination of blood vessels, while a blue filter help with spotting scratches on the cornea(Opthalmologyweb, 2012, p. 1)[13] . A positive to using the direct ophthalmoscope is that the image is magnified more than the indirect ophthalmoscope. This will allow the optometrist to have a larger area to look at.







This is a ray diagram showing the light from the ophthalmoscope go into the patients eye.
This is a ray diagram showing the light from the ophthalmoscope go into the patients eye.













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2.2 Binocular Indirect Ophthalmoscope (BIO)

This is a binocular indirect ophthalmoscope.  It gives the optometrist a better view of the eye than the direct ophthalmoscope.
This is a binocular indirect ophthalmoscope. It gives the optometrist a better view of the eye than the direct ophthalmoscope.
The Binocular Indirect Ophthalmoscope is another type of the ophthalmoscope that goes around the optometrists head and then has the eyepiece coming off of the headset. There are different strengths for the lenses on BIO's. The strengths can be anywhere from +14D to +30D. Lenses below +20D give more magnification (Barnard, 2012, p. 1)[15] . There are both advantages and disadvantages of using the BIO. Some advantages are that there is a bigger picture for the optometrist to see, it is a brighter image, and finally there is less distortion to the image. Some of the disadvantages are that the image is inverted both upside-down and side to side. This means the top is really the bottom and vice versa, and the right is really the left and the left is the right. This can make it hard for new optometrists to remember to put it this way in drawings( Veatch, 2012, p. 1)[16] .




This is how light from the BIO goes into the eye and creates an image of the eye.
This is how light from the BIO goes into the eye and creates an image of the eye.






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3.0 Effect on Everyday Life


How have eye examination tools effected everyday life?
The phoropter is one of the most commonly used tools in eye exams to find your prescription.
The phoropter is one of the most commonly used tools in eye exams to find your prescription.

external image ophthalmoscope.jpgEye examination tools have had a great effect on human life since they started being used on a regular basis. Without the technology we have now in the eye care section, people would not be who they are now. Being able to find a perfect lens for someone so they can once again have 20/20 vision or close to it makes life much easier for them. Also it is easier to complete tasks when your vision is clear and not blurred or distorted. Also it is now not such a bad thing when you have to where glasses like it used to be. Now glasses are made to be stylish, to go with your everyday outfits when not too long ago it was only about being able to see. Glasses are much more prominent in people's lives and now with the phoropter and ophthalmoscopes it make sit easier to be diagnosed and get back to living the life you did with perfect vision.
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4.0 What have you learned?



1. If you went to an eye exam and needed to look for a disease in your eye, what tool would you use?
a) Phoropter
b) Direct Ophthalmoscope
c) Binocular Indirect Ophthalmoscope

2. If you wanted a large un-inverted image of you eye what tool would you use?
a) Phoropter
b) Direct Ophthalmoscope
c) Binocular Indirect Ophthalmoscope

3. To find your refractive error what tool would you use?
a) Phoropter
b) Direct Ophthalmoscope
c) Binocular Indirect Ophthalmoscope

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5.0 Deeper look into Ray Diagrams

This is the ray diagram for the phoropter
This is the ray diagram for the phoropter


This ray diagram for the phoropter shows how the different lenses can refract the light into different places in your eye. When the light stops short of your retina like in picture "B" you would have nearsightedness meaning you have trouble seeing objects far away. In "C" the focus is behind the retina meaning the person is farsighted. This means that the person would have trouble seeing objects close to them. Finally in "D" since there is no one point of focus the person would have astigmatism. In the end picture "A" wis perfect vision when all the images and light refract to the retina ( Heiting, 2010, p. 1)[17] .





This is the ray diagram for the Direct Ophthalmoscope
This is the ray diagram for the Direct Ophthalmoscope
Here the direct ophthalmoscope is being used and the light goes through the volk lens, then through the front of the eye and refracts to the back of the eye. This allows the optometrist to see the fundus. The volk lens straightens out the light so it can then refract properly into the patients eye.




this is the ray diagram for the Binocular Indirect Ophthalmoscope
this is the ray diagram for the Binocular Indirect Ophthalmoscope

This is the ray diagram showing how the binocular indirect ophthalmoscope works. light from the light source travels into a mirror that reflects that light into the eye. The optometrist views the eye through a central hole. The image of the eye reflects back and then the examiner can see the image clearly ( Riley, 2012, p. 1)[18] .




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6.0 Articles related to the topic.


There were two articles found that give information about eye exams and why they are necessary. This relates to the tools because this is why new technology is being developed. The more you are supposed to get eye exams, the better the technology should be. The first article is from the National Post, and is about how regular eye exams are always important. There was a four year old girl who would have not gotten an eye exam unless she had symptoms like she did. She ended up having farsightedness but if they had seen an optometrist before they might have diagnosed this earlier and not had to wait for the symptoms to come into play (National-Post, 2012, p. 1)[19] . The second article from LiveStrong is about how important eye exams really are. It states that eye exams are really important to get for many reasons. The main reason is to see if you need glasses because of a refractive error. Also getting an eye exam can detect glaucoma before the symptoms even start ( Doup, 2010, p. 1)[20] . Eye exams are not some thing that should be taken lightly as having clear vision is very important.



7.0 Glossary


Phoropter- A tool with different lenses used for refraction of the eye during an eye exam.[21]
Ophthalmoscope- A lighted tool that is used to look at the inside of an eye, specifically, the retina and optic nerve.[22]
Retina- A multi-layered membrane on the inner eyeball that is connected to the brain by the optic nerve.[23]
Optic Nerve- The nerve that carries images from the retina to the brain.[24]
Refractive Error- A loss of the ability to focus on an image correctly. [25]
Astigmatism- When the cornea can not focus an object to the retina. This will result in a blurry image.[26]
Glaucoma- An eye disease caused by high pressure in the eye. Can lead to loss of vision. [27]
Fundus- The back part of the eye ball.[28]
Cornea- The outside part of the eye that is transparent. [29]

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8.0 Interactive tutorial


This is a widget showing how a lens in the binocular indirect ophthalmoscope would work. You can tell this is the lens because the object is inverted and that is the same in the binocular indirect ophthalmoscope. ( Dubson, 2011, p. 1)[30] In this tutorial you can move the object starting on the left, or the lens. Try different positions and see where the image moves.
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  1. ^ Bedinghaus, T., & O.D.. (2009, February 3). Eye Exam - Eye Exam Equipment. About Vision - Eyes and Vision Problems - Eye Health - Vision and Eye Care. Retrieved May 26, 2012, from http://vision.about.com/od/eyeexaminations/ig/Eye-Exam-Equipment/
  2. ^ Definition of Ophthalmoscope. (2012, March 19). Definition of Ophthalmoscope. Retrieved May 26, 2012, from www.medterms.com/script/main/art.asp?articlekey=4645
  3. ^ Bedinghaus, T., & O.D.. (2009, February 3). Eye Exam - Eye Exam Equipment. About Vision - Eyes and Vision Problems - Eye Health - Vision and Eye Care. Retrieved May 26, 2012, from http://vision.about.com/od/eyeexaminations/ig/Eye-Exam-Equipment/
  4. ^ Bedinghaus, T. (n.d.). Phoropter.About Vision - Eyes and Vision Problems - Eye Health - Vision and Eye Care. Retrieved May 26, 2012, from http://vision.about.com/od/eyeexaminations/ig/Eye-Exam-Equipment/phoropter.htm
  5. ^ Heiting, G., & OD. (n.d.). Refractive Errors and Refraction - How the Eye Sees. All About Vision - Complete Consumer Guide About Vision and Eye Care. Retrieved May 27, 2012, from http://www.allaboutvision.com/eye-exam/refraction.htm
  6. ^ Rockwell, K. (2010, September 2). What Causes Astigmatism? | LIVESTRONG.COM. LIVESTRONG.COM - Lose Weight & Get Fit with Diet, Nutrition & Fitness Tools | LIVESTRONG.COM. Retrieved May 26, 2012, from http://www.livestrong.com/article/220276-what-causes-astigmatism/
  7. ^

    Definition of ophthalmoscope - NCI Dictionary of Cancer Terms - National Cancer Institute. (n.d.).Comprehensive Cancer Information - National Cancer Institute. Retrieved May 26, 2012, from http://www.cancer.gov/dictionary?cdrid=46247
  8. ^ informed, g., healthy, s., organized, k., & you., y. c. (2012, May 23). Five Common Glaucoma Tests | Glaucoma Research Foundation. Glaucoma Research Foundation. Retrieved May 26, 2012, from http://www.glaucoma.org/glaucoma/diagnostic-tests.php
  9. ^ Manufacturer. (n.d.). Bin. Indirect Vs. Direct Ophthalmoscopes | Veatch Ophthalmic Instruments. Ophthalmic Equipment, Optometry Equipment, Ophthalmic Supplies From Veatchinstruments.com | Veatch Ophthalmic Instruments. Retrieved May 26, 2012, from http://www.veatchinstruments.com/info.asp?topic=Bin.%20Indirect%20Vs.%20Direc
  10. ^ Find Direct Ophthalmoscopes. (n.d.).Home | OphthalmologyWeb: The Ultimate Online Resource for Ophthalmologists. Retrieved May 26, 2012, from http://www.ophthalmologyweb.com/Ophthalmic-Practice-Setup-Ophthalmic-Equipment/5501-Direct-Ophthalmoscope/
  11. ^ direct ophthalmoscope - definition of direct ophthalmoscope by the Free Online Dictionary, Thesaurus and Encyclopedia.. (n.d.). Dictionary, Encyclopedia and Thesaurus - The Free Dictionary. Retrieved May 26, 2012, from http://www.thefreedictionary.com/direct+ophthalmoscope
  12. ^ scanning laser ophthalmoscope - definition of scanning laser ophthalmoscope in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.). Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/scanning+laser+ophthalmoscope
  13. ^ Find Direct Ophthalmoscopes. (n.d.).Home | OphthalmologyWeb: The Ultimate Online Resource for Ophthalmologists. Retrieved May 26, 2012, from http://www.ophthalmologyweb.com/Ophthalmic-Practice-Setup-Ophthalmic-Equipment/5501-Direct-Ophthalmoscope/
  14. ^ How To Use the Direct Ophthalmoscope - YouTube . (n.d.).YouTube - Broadcast Yourself. . Retrieved May 27, 2012, from http://www.youtube.com/watch?v=-7Sh2H1jgUU&feature=g-hist
  15. ^ BSc(Hons).FCOptom.DCLP.FAAO., S., & A.Field..MSc.FCOptom.DCLP.FAAO.. (n.d.). Head Band Indirect Ophthalmoscopy. American Academy of Optometry(British Chapter). Retrieved May 27, 2012, from http://www.academy.org.uk/tutorials/headband.htm
  16. ^ Manufacturer. (n.d.). Bin. Indirect Vs. Direct Ophthalmoscopes | Veatch Ophthalmic Instruments. Ophthalmic Equipment, Optometry Equipment, Ophthalmic Supplies From Veatchinstruments.com | Veatch Ophthalmic Instruments. Retrieved May 26, 2012, from http://www.veatchinstruments.com/info.asp?topic=Bin.%20Indirect%20Vs.%20Direc
  17. ^ Heiting, G., & OD. (n.d.). Refractive Errors and Refraction - How the Eye Sees. All About Vision - Complete Consumer Guide About Vision and Eye Care. Retrieved May 27, 2012, from http://www.allaboutvision.com/eye-exam/refraction.htm
  18. ^ RIley, H. D. (n.d.). Binocular Indirect Ophthalmoscopy. Home Page. Retrieved May 27, 2012, from http://www.opt.indiana.edu/riley/HomePage/BIO_lecture_notes/TEXT_BIO_Exam3.html
  19. ^ Regular eye exams crucial at every age, experts say | Vision | Health | Life | National Post. (2012, May 16).National Post | Canadian News, Financial News and Opinion. Retrieved May 27, 2012, from http://life.nationalpost.com/2012/05/16/regular-eye-exams-crucial-at-every-age-experts-say/?__lsa=384e5e3a
  20. ^ Doup, L. (2010, June 2). The Importance Of An Eye Exam | LIVESTRONG.COM. LIVESTRONG.COM - Lose Weight & Get Fit with Diet, Nutrition & Fitness Tools | LIVESTRONG.COM. Retrieved May 27, 2012, from http://www.livestrong.com/article/138100-the-importance-eye-exam/
  21. ^ phoropter - definition of phoropter in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.). Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/phoropter
  22. ^ Definition of ophthalmoscope - NCI Dictionary of Cancer Terms - National Cancer Institute. (n.d.).Comprehensive Cancer Information - National Cancer Institute. Retrieved May 26, 2012, from http://www.cancer.gov/dictionary?cdrid=46247
  23. ^ retina - definition of retina by the Free Online Dictionary, Thesaurus and Encyclopedia.. (n.d.). Dictionary, Encyclopedia and Thesaurus - The Free Dictionary. Retrieved May 27, 2012, from http://www.thefreedictionary.com/retina
  24. ^ optic nerve - definition of optic nerve by the Free Online Dictionary, Thesaurus and Encyclopedia.. (n.d.).Dictionary, Encyclopedia and Thesaurus - The Free Dictionary. Retrieved May 27, 2012, from http://www.thefreedictionary.com/optic+nerve
  25. ^ refractive error - definition of refractive error in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.). Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/refrac
  26. ^ astigmatism - definition of astigmatism in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.).Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/astigmatism
  27. ^ glaucoma - definition of glaucoma in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.). Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/glaucoma
  28. ^ fundus - definition of fundus in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.). Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/fundus
  29. ^ cornea - definition of cornea in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.. (n.d.). Medical Dictionary. Retrieved May 27, 2012, from http://medical-dictionary.thefreedictionary.com/cornea
  30. ^ Dubson, M. (n.d.). Geometric Optics 2.05. PhET: Free online physics, chemistry, biology, earth science and math simulations. Retrieved May 27, 2012, from http://phet.colorado.edu/sims/geometric-optics/geometric-optics_en.html