Tear Break Up Time Test (TBUT)

A clinical test used to assess for evaporative dry eye disease and tear quality. To measure TBUT, fluorescein is instilled into the patient's tear film and the patient is asked not to blink while the tear film is observed under a biomicroscope (diffuse slit lamp illumination). This procedure allows the technician to evaluate the quality of the tear film, primarily the lipid layer. "Normal" tear break up time (appearance of dry/dark spots on the cornea) is 10-12 seconds. A tear break up time of 5 seconds would suggest the patient has low quality tears.

Schirmer's Test

A test used to evaluate tear quantity. A normal level of production is considered to be over 10 millimeters (mm) of tears on the litmus paper in 5 minutes. Anything under 10 mm is considered to be an abnormally low level of tear production. A measurement of less than 5 mm is considered severe dry eye.

Shadow graph

An instrument used for magnification of the edge of a rigid contact lens. Can be use to verify the overall RGP lens diameter.

Radiuscope

Instrument used for measuring the radius of curvature of the anterior and posterior surfaces of rigid contact lenses (base curve).

Profile Analyzer

measures the peripheral curves (blends)

Measuring Magnifier

An instrument that allows simultaneous verification of lens diameter, optic zone width and peripheral curve width. Measures posterior optic zone and overall diameter of RGP lens.

Biomicroscope

AKA Slit Lamp or Burton Lamp. Used to gather information on the overall heath of the eye/cornea prior to contact lens fitting. Consists of a microscope and a light source.

Rheostat

An electrical instrument used to control a current by varying the resistance. This allow adjustment of the light without removing your hand from the joystick during slit lamp illumination.

Keratometer

A keratometer, also known as an ophthalmometer, is a diagnostic instrument for measuring the curvature of the anterior surface of the cornea, particularly for assessing the extent and axis of astigmatism.Calibrated for the index of refraction of the tear film covering the cornea. 1.3375.

Tonometer

an instrument for measuring the pressure in a part of the body, such as the eyeball (to test for glaucoma) or a blood vessel.

Phoropter

An instrument used to test individual lenses on each eye during an exam.

Keratoscope

A keratoscope, sometimes known as Placido's disk, is an ophthalmic instrument used to assess the shape of the anterior surface of the cornea. Often used to evaluate corneal irregularities.

Lensometer

Instrument used for determining the refractive power of a spectacle or contact lens

Pachymeter

Test for measuring corneal thickness

v-groove gauge

measures the diameter of a rigid contact lens.

Ishihara test

Color Blind Test · This color vision test, known as the Ishihara Test, makes numbers out of dots that are a different color than the dots surrounding them.

Slot Gauge

is used to measure the diameter of a rigid lens