Posts Tagged ‘differnce direcet and indirect opthalmoscopes opthalmoscopy’

What is the difference between direct and indirect ophthalmosopes (ophthalmoscopy)?

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This is a summary of the differences between direct and indirect ophtalmoscopes (ophthalmoscopy). I searched the internet for a page that answer this question adequately, but did not find any. Luckily, I found the answer in a book entitled: “Textbook of opthalmology” (2nd edition, 2001) by E. Ahmed. This is a tabulation of the differences mentioned in this book only. I didn’t use any other source.

Update 15/01/2014:
This post is now a famous one in my Blog. It brings me a lot of visits (4465 visists so far). I need to thank the doctor who asked me to research this topic. Dr. Khalil Alsalem thanks a lot 🙂

Direct Ophthalmoscopy Indirect ophthalmoscopy
Magnification About 15 times 5 times when a +13D condensing lens is used
Diameter of the field of observation\view Smaller (about 10o in diameter) Wider (about 37o in diameter)
Brightness There is relatively low brightness There is relatively greater brightness
Structures seen Central retina only Peripheral retina seen (by using a scleral depressor in addition to the indirect ophthalmoscopy itself)
Image of the fundus that is seen Virtual & erect image Real & inverted image
Stereopsis Image formed is not stereoscopic Binocular indirect ophthalmoscopy provides better stereopsis
Retina anterior to the equator Not well seen (seen with difficulty) Seen better
Scleral indentation Difficult Can be easily done in binocular indirect ophthalmoscopy
Visualization in hazy media Poor Better

What is the difference between direct and indirect ophthalmoscopes (ophthalmoscopy)?

This is a summary of the differences between direct and indirect ophthalmoscopes (ophthalmoscopy). I searched the internet for a page that answer this question adequately, but did not find any. Luckily, I found the answer in a book entitled: “Textbook of opthalmology” (2nd edition, 2001) by E. Ahmed. This is a table of the differences mentioned in this book only. I didn’t use any other source.

Update 15/01/2014:
This post is now a famous one in my Blog. It brings me a lot of visits (4465 visits so far). I need to thank the doctor who asked me to research this topic. Dr. Khalil Alsalem thanks a lot 🙂

Direct Ophthalmoscopy Indirect ophthalmoscopy
Magnification About 15 times 5 times when a +13D condensing lens is used
Diameter of the field of observationview Smaller (about 10o in diameter) Wider (about 37o in diameter)
Brightness There is relatively low brightness There is relatively greater brightness
Structures seen Central retina only Peripheral retina seen (by using a scleral depressor in addition to the indirect ophthalmoscopy itself)
Image of the fundus that is seen Virtual & erect image Real & inverted image
Stereopsis Image formed is not stereoscopic Binocular indirect ophthalmoscopy provides better stereopsis
Retina anterior to the equator Not well seen (seen with difficulty) Seen better
Scleral indentation Difficult Can be easily done in binocular indirect ophthalmoscopy
Visualization in hazy media Poor Better