Phoropter

The phoropter is an instrument used for holding lenses in front of the eyes of the subject. We can test vision and prescribe lenses based on the results we get from this instrument. It also allows us to test muscle balance, focusing ability and eye posture.

Photo at right: Phoropter

Ophthalmoscope

The ophthalmoscope is used for viewing the retina of the eye. The retina is the back surface of the eye which receives the image focused by the cornea and lens. It is the equivalent of the film of a camera. With the ophthalmoscope, we can view the nerve head (where the optic nerve enters the eye) and the blood vessels which feed the retina.

Photo at right: Ophthalmoscope

Keratometer

The Keratometer is an instrument used for measuring the curvature of the cornea. The curvatures of the cornea are Important for fitting contact lenses and determining data for laser vision correction.

Photo at right: Keratometer
 

Biomicrosope (or Slit Lamp)

The Biomicroscope, or slit lamp is simply a microscope designed to give a magnified image of the front of the eye. Looking through the biomicroscope you can even see individual blood cells traveling in the thinner vessels visible on the front of the eye. This instrument is essential for evaluating contact lenses, corneal disease, lid disease, and inflammations inside of the eye. It is also necessary for evaluating flap integrity in LASIK patients.

Photo at right: Biomicroscope (Slit Lamp)

Photo below: View from Slit Lamp

Retinal Camera

This instrument really gives the same view as the ophthalmoscope but gives us a permanent record of the retina on that day. Sometimes, a retina may appear perfectly normal; but the fact that it has changed in certain ways over the years may indicate a disease condition. The retinal pictures throughout this web page were all taken with a retinal camera.

Photo at right: Retinal Camera

Tonometers

Tonometers are used to evaluate eye pressure. High eye pressure can indicate many forms of glaucoma and iritis. There are many different types of tonometers. Most commonly used are the applanation tonometer and the non-contact tonometer. The non-contact tonometer works by using an air puff. The instrument blows air onto the eye to flatten the central part of the cornea. The more air required – the higher the pressure. The applanation tonometer is placed right on the eye (an anaesthetic is used). The applanation tonometer is preferred as it is a more accurate instrument.

Photo above: Applanation Tonometer

Photo at right: Non-Contact Tonometer
 

Autorefractor

The autorefractor is an instrument which gives an estimate of the refraction, or eyeglass prescription of an individual without asking for any subjective responses. The test takes only a few seconds and provides a starting point for subjective testing (with the phoropter) when no other information is available.

Photo at right: Auto refractor
 

Perimeter

The perimeter is an instrument used for plotting a map of peripheral vision. We actually map retinal sensitivity to light over most of the retina. Subtle changes in retinal sensitivity can indicate glaucoma, inflammations behind the eye or even tumors behind the eye.

Photo at right: Visual Field from Perimeter

Eyetrac

The eyetrac Recorder is an instrument used for diagnosing conditions which affect reading. The recorder gives
A print-out of eye movements made when reading. Children who are having difficulty in school with reading can
Benefit from an analysis of reading eye movements.

The eye trac on the left is a normal reading movement. The Trac on the right is from a student having difficulty with reading. Many forms of reading skill developmental problems can be remediated.

Photo at right: Eyetrac recorder