how to work Ophthalmoscope
Ophthalmoscopy is used to understand the structure of the eye and to look inside the fundus of one eye and other structures using an ophthalmoscope. Commonly used to examine retinal and vitreous humor.
With the help of ophthalmoscope, doctors can diagnose the disease properly as well as treat it.
Basic components of Ophthalmoscop
|Patient side||User side|
|1. Lens||1. Light|
|2. Eye rest||2. Vertical dial|
|3. Vertical dial||3. Horizontal dial|
|4. Red button|
|5. Power base|
|6. Number settings|
|8. Eye rest|
|9. Vertical dial|
|10. Red button|
|11. Power base|
|12. Number settings|
1. Direct ophthalmoscope
2. Indirect ophthalmoscope
a. Image produced will be upright, or unreversed
b. Approximately 15 times magnification
Direct ophthalmoscope is the easiest instrument of choice by physicians for fundus examination. This allows a magnified, monocular image of the retina and optic disc.
Direct ophthalmoscope working principle
In direct ophthalmoscopy if the eye is emmetropic, light rays emanating from a point in the fundus emerge as parallel beams. If this beam enters the pupil of an emmetropic observer, the rays are focused on the retina of the observer and form an image of the patient’s retina on the retina of the observer. This is called direct ophthalmoscopy.
a. Image produced will be inversed, or reversed
b. Approximately 2 to 5 times magnification
It is called indirect ophthalmoscopy because, BIO is one of the methods used to view the retina, which has a wide field of view and stereoscopic view of the retina. The BIO device also allows dynamic observation of the retina by moving the lens and applying scleral depression.
The procedure is “indirect” because the fundus is viewed through a hand-held condensing lens. Its main use is the binocular indirect ophthalmoscope, an optical instrument worn on the examiner’s head, and sometimes attached to glasses, which are used to observe the fundus or the back of the eye. This produces a stereoscopic image with 2x and 5x magnification.
Indirect ophthalmoscop principle
The main principal of indirect ophthalmoscopy is, in short, the purpose of the ophthalmoscopy lens in indirect ophthalmoscopy is to redirect the diverging pencil of light from the patient’s pupil towards the observer’s eye. In doing so, the lens focuses parallel rays within each pencil into an inverted aerial image of the patient’s fundus.
difference between Direct ophthalmoscope and Indirect ophthalmoscope
The main difference between the two is as follows, direct ophthalmoscopy is one that produces a straight, or inverted image of about 15 times magnification. Indirect ophthalmoscopy is one that produces an reserved or inverted image at 2 to 5 times magnification.
Direct ophthalmoscop Indirect ophthalmoscop
a. Good magnification a. Good for peripheral retina assessment
b. Good macular assessment b. Good for various retinal procedures
c. Light and portable
d. Easy to use
e. Size compactable
opthalmoscope use and importance
Ophthalmoscopy is a test that allows your ophthalmologist, or eye doctor, to see the back of your eye. This part of your eye is called the fundus, and includes the retinal optic disc.
Ophthalmoscopes are used to detect and evaluate symptoms of retinal detachment or eye diseases such as glaucoma. Ophthalmoscopy may also be done if the patient has signs or symptoms of high blood pressure, diabetes, or other diseases that affect the blood vessels.
Mostly concave mirrors are used in optical instruments such as ophthalmoscopes. Ophthalmoscope consists of a concave mirror with a hole in the middle. The user focuses through a small hole in the back of the concave mirror while a light beam is directed into the patient’s eyeball.
The invention of the ophthalmoscope by noted scientist Hermann von Helmholtz was extremely exciting to ophthalmologists of the time and promoted respect and recognition of ophthalmology as a medical specialty.