for more information contact John Fridge
FOCAL LENGTH - Focal Length is measured on a Nodal Slide Bench using a 1951 AFT or other type of resolution target. Apertures to 80 millimeters, focal lengths to 4 meters, visible light 400 to 700 nm. Measuring equipment traceable to NIST.
MODULATION TRANSFER FUNCTION - MTF is measured directly at over 150 discrete spatial frequencies. Testing at finite or infinite conjugates, on or off axis.
IMAGE PLANE - Resolution - Field Curvature - Distortion - Chromatic and Spherical Aberration - Astigmatism - Prism - Numerical Aperture or Field of View - Magnification
MAGNIFICATION - Magnification is determined by the ratio of the measured exit pupil and entrance pupil. Typical accuracy is one percent. Resolution (resolving power), Chromatic and Spherical Aberration, and Astigmatism can also be measured.
FIELD of VIEW - Field of View is measured in object space. Typical accuracy is 1' of arc.
EYEPIECE ADJUSTMENT - Eyepiece eye relief is measured from the ocular surface or eye ring. Typical accuracy is 0.02 to 0.10 mm. Eyepiece Dioptering is determined at the measured eye relief distance. Typical accuracy is 0.1 Diopter.
ISO and ANSI STANDARDS - Measurements of IOL power and image quality are made according to ISO and ANSI standards. Monofocals, Multifocals and Torics are tested in air, wet cell or in the ISO eyemodel.
FOCAL LENGTH - Focal Length is measured as per ANSI specs, on a Nodal Slide Bench, using collimated light at 550 nm, using a 3 mm aperture.
IMAGE QUALITY - ANSI measurement of Resolution is made in collimated light using the 1951 Air Force Target. MTF is measured directly, using the ISO eyemodel.
ISO and ANSI STANDARDS - Measurements of Ophthalmic power, prism and image quality are made according to ANSI standards.
SPECTACLES and CONTACTS - Focal Length and Image Quality are measured as per ANSI specs, on a Nodal Slide Bench, using collimated light at 550 nm.
PROTECTIVE and FASHION EYEWEAR - Measurement of Prism Power and Prism Imbalance is made as per ANSI specs. Image Quality of these lenses is determined using a high quality achromat. Either Resolution or MTF can be measured.
OPTICAL BENCHES - A variety of stock and custom test benches are available. These range from simple benches for visual/manual measurements, to automated MTF systems.
DIOPTERSCOPES - Diopterscopes are useful for checking the adjustment of instrument eyepieces, and for quick measurements of chromatic or spherical aberration and astigmatism.
CERTIFIED CALIBRATION STANDARDS - Calibration Standard Lenses are available, with Certified measurement of focal length and resolution traceable to NIST. Certification service is also availble.
IN-HOUSE TESTING REQUIREMENTS - Our years of optical testing experience can be useful in helping to develop and impliment quality assurance programs for your optical products.
VALIDATION STUDIES - We are experienced in developement and implimentation of Validation programs, to assure compliance with regulatory requirements for IOLs.
TECHNICAL REPORTS - Technical Reports on testing methods and standards, proper methods for calibration of test equipment, etc., can be written to meet your requirements.
The following links provide useful information for anyone interested in the field of optics. This list is constantly being updated and added to. If some of these links do not work, or if you would like to recommend a new link, please let me know by email. You can also begin a search for specific information using the "Yahoo" search engine.
for more information contact John Fridge at Optical Testing Laboratory
27080 Lake Drive - Pioneer, CA 95666 - Phone (209) 295-8660 Fax (209) 295-8661