Wavefront sensor to replace the optician ?

[Paulmw]

Found this on an optical site, thought it was interesting.....

Eye examinations at the opticians could become more accurate and much less subjective with a wavefront sensing system.

Based on a Shack-Hartmann wavefront sensor, which detects the "ripples" of light waves reflected when a laser hits an object, the Complete Ophthalmic Analysis System from WaveFront Sciences, of Albuquerque, NM, can tell opticians precisely what prescription a particular eye needs.

Another application is as a precursor to laser eye surgery, as the system can create a detailed map of the eye.

The system is a spin-off of similar technology used in more conventional optical metrology applications, such as checking the shape of components on a production line. For example, another Shack-Hartmann sensor system made by French company Imagine Optics is used on a Ford production line in Bordeaux, to ensure quality control of the shape of pinions used in gearbox production. MH

Story courtesy of Opto and Laser Europe magazine.

[Jeff Trail]

Paul,

What is the sight URL ? .. BTW one of the problems I have seen with about all these systems is they do not allow for vertex and accomidation .. did you ever notice auto refracters have this bad habit of "over refracting" like MD's :)

Post the sight I wouldn't mind checking it out..

Jeff "always curious " Trail

[This message has been edited by Jeff Trail (edited 07-11-2000).]

[Paulmw]

Here it is but I'm afraid there's not much more info than what I posted....
http://optics.org/oo/news/newsbytes.html

You might try looking these guys up on the 'net. Sorry !

[Shwing]

!Hola

Please read the following as well:

"Posted by Shwing on February 16, 2000 at 20:18:56:

Reported in the National Post, Wed., Feb., 16/2K, (Reuters):


'Finally, and end to eye charts may be in sight

The 100- year old eye-chart system is in danger of being replaced by a new technique invented by an
astrophysicist.

The new device can precisely mesure how light waves are bent by each human eye. Since the current method
relies on the patient's judgement of whether a particular set of lenses results in better vision, access to more
objective, scientific data will give doctors(sic)much more accurate measurements, according to makers of the
devices.

In addition, the combination of wavefront measurements with increasingly popular vision correction surgery
could help surgeons to be more precise in using lasers to reshape the cornea.

In the mid- 1970's, Josef Bille, director of the Institute of Applied Physics at the University of Heidleberg,
developed 'wavefront technology' to correct for the distortion to light rays, and the perception of shapes in
space, caused by their passage through Earth's atmosphere.

This technology has led to a wavefront sensor that tracks and measures the course of light rays through the eye.
The system can detect even the smallest aberration at any point in the optical system.

One use of wavefront technology is for patients undergoing laser-vision correction surgery, but it can also be
used to improve the fit of contact lenses and eyeglasses.

Current laser-vision correction techniques reshape the cornea to a standard spherical shape based on the
patient's(sic) manifest refraction: the trial lens measurment used to prescribe contacts or glasses.

In clinical trials now under way, data from the wavefront sensing device is loaded on a floppy disk that is then
plugged into the laser machine next door.

Eventually, 'custom ablation' will allow surgeons to map and sculpt the eye so exactly that they can provide
eyesight better than 20/20.'

Check the dear previous version of Optiboard for some of the responses I received. I am working on linking them.



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Shwing;-}

[RP]

Wavefront sensing technology does improve the ability to measure refractive error and higher order aberrations of the eye. It's still not clear (no pun intended) that these data can be used to improve refractive surgery results, but initial tests are hopeful.

Vertex distance is not an issue, as one can control/measure the eye in position.

Accommodation is an issue, but cycloplegic drops can freeze accommodation (though the larger pupil size will change the aberrations detected). Software might be used to artificially shrink the area of analysis back to the average pupil size of the patient.

Hope this helps.