During your consultation with the ophthalmologist, you will be examined with a series of instruments designed to analyze your visual field. But what are these tools called, and what are their functions? Slit lamp, Goldmann or Friedmann perimeter, ophthalmometer or ophthalmoscope… The ophthalmologist’s tools an article to discover all these instruments to study your visual field that will soon have no secrets for you!

The ophthalmologist's tools
Corneal examination

Let us look at the Goldmann or Friedmann perimeters.

This apparatus is designed to observe the visual field, the Goldmann or Friedmann perimeters allow the ophthalmologist to analyze the peripheral visual field and to diagnose neurological ocular deficiencies.

The difference between the Goldmann and Friedmann perimeters lies in the type of field of view being analyzed. The first one offers a more precise observation of the field in the periphery. The second is optimized for the central field of vision.

The perimeter is a hemispherical dome shaped device, where you will be asked to sit during your consultation. Composed of a lantern, adjustable lighting and a fixation point, your eye focuses on a central point, where lights are projected and moved.

Thanks to this examination, a curve (isopter) is drawn by the specialist and allows them to obtain a measurement of your visual field. The areas of visual deficiency , blindness, narrowing of the field of vision, glaucoma or any other brain damage can be identified.

The slit lamp: an instrument to observe the smallest detail!

Also known as the biomicroscope, this device is used systematically during an eye examination by your ophthalmologist. The purpose of the slit lamp is to analyze the following structures of your eye: iris, lens, pupil, cornea, eyelids and the anterior vitreous body.

Invented by the Swedish doctor Allvar Gullstrand in 1911, all the details of your eye, even those of a few tenths of a micron, are visible and can be analyzed by your eye specialist.

How does biomicroscopy work? It is simply thanks to a small mirror, a light, and a microscope, a light slit system projected on your eye. The slit is adjustable by the ophthalmologist, in size and orientation, with several possible magnifications to properly analyze your eye.

The ophthalmoscope, or how to examine the visual field in depth?

Invented by the Prussian scientist Helmholtz in 1851, the ophthalmoscope is a device for examining the visual field in straight images. It is used to examine the eye fundus. This examination is important for any patient since it allows us to detect possible abnormalities of the retina.

The ophthalmoscope is composed of three parts: a handle, a lighting system and a screwed head, composed of a rotating wheel with a set of lenses and a set of interchangeable apertures, it is simple and practical to use for ophthalmologists.

During your examination, light is projected from the bulb of the ophthalmoscope, reflected at the right angle and projected through the retina of the eye being examined. The retina is illuminated through the iris.

The ophthalmometer to analyze your cornea

The ophthalmometer, also called keratometer, is a device to examine the curvature of the anterior surface of the cornea. It is measured through the production of images reflected on the cornea in its two main meridians.

During your consultation, the ophthalmometer takes the form of a device in which you place your chin and your forehead on a support and focus on a specific image. The examination takes place in a dark room, where one eye, then the other, is examined by the ophthalmologist.

Technique developed by Helmholtz, then simplified by Louis Emile Javal in 1880, the ophthalmometer is also used to study the adaptation to contact lenses or calculate the power of intraocular implants for the patient. Astigmatism can be measured in this way, since it results from an unequal curvature of the cornea.

To conclude this article on The ophthalmologist’s tools !

Now that the ophthalmologist’s tools no longer hold any secrets for you, make an appointment at COP9!

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