A. Image is real and inverted
B. Details of fundus can be seen even with slightly hazy media
C. Magnification is more than direct ophthalmoscope
D. Used for seeing periphery of fundus
Ans:C. Magnification is more than direct ophthalmoscope
This instrument is indirect ophthalmoscope
Ophthalmoscopy, also called fundoscopy
- It is a test that allows to see inside the fundus of the eye and other structures using an ophthalmoscope (or fundoscope). It is crucial in determining the health of the retina, optic disc, and vitreous humor.
- It is of two major types:
- Direct ophthalmoscopy : produces an upright, or unreversed, image of approximately 15 times magnification.
- Indirect ophthalmoscopy: produces an inverted, or reversed, direct image of 2 to 5 times magnification.
|Features||Direct ophthalmoscopy||Indirect ophthalmoscopy|
|Condensing lens||Not Required||Required|
|Examination distance||As close to patient’s eye as possible||At an arm’s length|
|Image||Virtual, erect||Real, inverted|
|Illumination||Not as bright; not useful in hazy media||Bright; useful for hazy media|
|Area of field in focus||About 2 disc diameters||About 8 disc diameters|
|Accessible fundus view||Slightly beyond equator||Up to Ora serrata i.e. peripheral retina|
|Examination through hazy media||Not possible||Possible|
- Each type of ophthalmoscopy has a special type of ophthalmoscope:
- The direct ophthalmoscope is an instrument about the size of a small flashlight (torch) with several lenses that can magnify up to about 15 times. This type of ophthalmoscope is most commonly used during a routine physical examination.
- An indirect ophthalmoscope, on the other hand, constitutes a light attached to a headband, in addition to a small handheld lens. It provides a wider view of the inside of the eye.
- It allows a better view of the fundus of the eye, even if the lens is clouded by cataracts.
- An indirect ophthalmoscope can be either monocular or binocular. It is used for peripheral viewing of the retina.