If you ever had an eye examination you must have gone through some instruments to get your eyes tested. You will be surprised to know the number of pieces of equipment involved in a comprehensive eye examination.
With the advancement of time, technology also progresses hand in hand. Today there is numerous equipment available to fulfill different diagnostic procedures in eye examinations.
But there are a few basic types of equipment that every optometrist will need in his day-to-day clinical practice.
Here are the pieces of equipment that should a clinician optometrist should have in his exam room –
Torchlight
For general examination and pupillary reactions.
Trial Box
The trial box consists of a trial frame, trial lenses, a Maddox rod, a stenotic slit, an occluder, and prisms. Trial frames and trial lenses are used to determine the refractive status of the patient. While other equipment is used for other tests. Trial lenses consist of two rows, one of concave spherical and cylindrical lenses and the other of convex spherical and cylindrical lenses.
Phoropter
An alternate piece of equipment of a trial box is used to test response and perception of visual acuity.
Jackson Cross Cylinder (JCC)
This instrument is by an optometrist to determine and verify the astigmatic corrective lens power of the patient. This is a sphere cylindrical lens in which the power of the cylinder is double the power of the sphere and of the opposite sign.
Visual Acuity Chart
It is an eye chart that is used to check the visual acuity of the patient. These charts come in different languages with variable letter sizes arranged in decreasing order from up to down.
The patient is asked to read the chart and refraction is done after determining its visual acuity.
Normally charts are incorporated into a single sheet of paper, but with the latest advancement, these charts are incorporated into Snellen Drum or Lcd T.V.
Slit - Lamp
Consists of a high illumination source, which can be focused and shine on the eye. It is used with a biomicroscope. Light source and biomicroscope work on a coaxial system with variable height and width of slit attached with different filters to inspect various parts of the eye such as the cornea, conjunctiva, anterior chamber, crystalline lens, etc.
Ophthalmoscope
An ophthalmoscope or funduscopy is an instrument that an examiner uses to see the condition of the fundus. It is done as a routine eye examination in which the health of the retina, optic disc, and vitreous are observed.
Retinoscope
When the patient is not cooperative or has difficulty in giving feedback to the optometrist due to a certain physical or mental condition Retinoscopy is used to measure the refractive status of the eyes.
Auto-refractor
It is another device used to measure refractive error and determine the correct prescription of eyeglasses or lenses.
The patient is asked to look inside the machine, where the patient sees a target that moves in and out of focus. The device takes readings by determining the retinal image position. An average prescription reading is given by the machine, which is further confirmed by the practitioner.
Tonometer
This device is used to measure Intraocular Pressure (IOP). IOP is the pressure of the fluids inside the eyeball. If the eyeball pressure is increased from a certain point it can damage the optic nerve at the back of the retina which can lead to vision loss.
Schirmer Strips
A small piece of paper having markings from 0 to 30 mm and made of 41 Whatman paper was used to check the aqueous layer of the tear film. Mostly used in the diagnosis of dry eye patients.