If you have never had a comprehensive eye examination, you may be surprised at the number of tests that are performed on such a small part of the body.  A complete eye exam involves the use of many pieces of equipment and several instruments.


The following is a partial list of equipment that we use in our offices to examine patient’s eyes:

The Phoropter: This is an instrument used during an eye examination to determine eyeglass prescriptions. Typically, the patient sits behind it and looks through it at a screen with different sized letters on it. The doctor changes lenses and other settings while asking the patient for feedback on which settings give the best vision.

The Slit Lamp:  This is a microscope that allows the doctor to closely examine the eye. This instrument is used to view structures of the eye such as the cornea, iris, and lens. However, with special lenses, it is possible to examine the back of the eye as well.

Retinal Camera:  This is used to photograph the back of the eye, including the retina. It is used to document eye diseases.

Indirect Ophthalmoscope:  This an instrument used for examining the interior structures of the eye, especially the retina. A Binocular Indirect Ophthalmoscope (BIO) is worn on an eye doctor’s head in order to have the use of both hands to examine the eyes.

Keratometer:  This is used to determine how flat or steep the cornea is. It is used to measure and diagnose conditions such as astigmatism or keratoconus.   A keratometer is commonly used to fit contact lenses as well.

Auto-Refractor:  This used to objectively measure a person’s refractive error and helps to determine prescription for eyeglasses or contact lenses.  This is just a starting point and should never be used alone to determine refractive errors.

Ultrasound:  We offer both A-scan and B-scan ultra-sonography.  The A-Scan is used to measure the length of the eye which is needed with implant power calculations with cataract surgery.  The B-scan is used to see behind dense cataracts and corneal scarring to see if the inside of the eye has any medical problems.

Tonometer:  This is used to measure the pressure inside the eye. The test is used to help detect glaucoma. There are several types of tonometers most of which touch the front to the eye after numbing drops are used.

Lensometer:  This instrument is used to measure the strength of glasses or contact lenses.

Retinoscope:  This is used to shine light into a patient’s eye to help determine a starting point for a patient’s refractive error.  A retinoscope is especially useful in prescribing corrective lenses for patients who are unable to give oral feedback to the eye doctor.

Direct Ophthalmoscope: This hand held instrument is used for examining the interior structures of the eye, especially the retina.

Visual Field Machine: This is used to detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumors or other neurological deficits.

OCT and HRT Machines: These are a non-invasive imaging testers. OCT and HRT machines use light waves to take cross-section pictures of your retina. With these machines, your eye doctor can see each of the retina’s distinctive layers.

Pachymeter: This machine is used to measure the thickness of your corneas.  Thinner corneas have a greater correlation to the development of glaucoma.

Corneal Topographer:  This maps the corneas and is used in the fitting and evaluation of contact lenses, diagnosing corneal disease, irregular astigmatism and keratoconus, and is necessary for laser vision correction evaluation and follow-up care.

Optos: The optomap® Retinal Exam produces an image that is as unique as your fingerprint and provides us with a wide view to look at the health of your retina. It is fast, easy, and comfortable for all ages.  The optomap® image is shown immediately on a computer screen so we can review it with you.

As is demonstrated from this partial list, the eyes are very intricate and require thorough examination with a lot of different, very specialized equipment.