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What is an Ophthalmoscope?
An ophthalmoscope is a medical instrument used to examine the eye. It is very important for a doctor to be able to view the interior of the eye, including the retina, located at the back of the eye. Although it is most often used to diagnose eye conditions, information gathered through an eye exam can be relevant to many other medical fields, including cardiology, neurology, and pediatrics. It has become one of the most commonly seen and recognized medical screening devices.
The most common type of ophthalmoscope consists of a concave mirror that reflects a small light within the instrument. A doctor examines the eye by looking through a monocular eyepiece into the eye of the patient. It is possible to view different depths of the eye at different magnifications by rotating a disc of varying lenses within the instrument itself. A routine examination of the eyes can be done quickly in a doctor's office. If the need exists for a more thorough examination, the doctor will sometimes dilate the patient's pupils beforehand, to provide a clearer and wider view of the inside of the eye.
The type of ophthalmoscope described above is also known as a direct ophthalmoscope. Less commonly used is the indirect ophthalmoscope, although these operate on basically the same principle. They usually consist of a light attached to a headband which is worn by the doctor. The doctor uses a hand-held lens to examine the eye. This type of instrument can provide a wider view of the eye, and is still quite useful, even if there are cataracts in the lens of the eye that would otherwise obscure the view.
As is the case with many inventions, more than one person can be said to have invented the ophthalmoscope. The first doctor ever to fashion a device for viewing the retina was Johannes Purkinje in 1823. In 1847, Charles Babbage developed a very functional early version of the device, but did not widely publicize the invention. The man who did was the German physician Hermann von Helmholtz, in 1850. He modified the earlier design slightly and made a model of it for demonstration.
For these reasons, Helmholtz is often credited with the invention. The first people to develop an ophthalmoscope that resembles the modern ones we know were Josh Zele and Jon Palumbo. In 1915, they came up with a hand-held version that is similar to those used in doctors' offices today.
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![The retina at the back of the eye is examined with an ophthalmoscope.]()
By: Alila Medical MediaThe retina at the back of the eye is examined with an ophthalmoscope. -
![Inventor Charles Babbage developed an early version of the opthalmoscope in 1847.]()
Inventor Charles Babbage developed an early version of the opthalmoscope in 1847.
Discussion Comments
I find it really cool that often things are invented by two different people at the same time. It makes me wonder about how inevitable inventions really are. How often is it really a great leap of logic and how often just the logical next step when all the ingredients are already present?
I'm sure for the ophthalmoscope, you need things like precision metal and glass making and knowledge of how the eye works and so forth.
Was it inevitable that it should look the way it does and work the way it does? Or just a coincidence that two people came up with it at the same time?
Of course, we'll never know for sure, but it's interesting to speculate.
@irontoenail - I don't think most of the things they put in your eye before using an ophthalmoscope will actually affect you in that way. It might have just been that you generally were stressed by the exam and felt sick because of that. Or maybe it was some kind of weird allergy reaction.
At any rate, you should definitely tell your optometrist and your doctor about it if you are considering having a vision correction surgery. They are definitely not something you want to go into if you are going to freak out on the operating table.
Ophthalmoscopes are quite mild in comparison to the laser, after all.
I quite like it when the optometrist uses the ophthalmoscope on my eyes because it causes you to see the arteries in the backs of your eyes as though they were in front of your eyes, and I find that really fascinating.
Although the last time they did it, the optometrist put a drop in my eye in order to keep my pupil wide and for some reason it made me feel very ill. In fact, I was worried I would throw up all over her and I had a hard time keeping my eye open.
It really worried me, because I'm hoping to get my vision corrected one day, and I don't want to get in there, and have them make me feel that ill for half an hour while they poke around at my eye.
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