Forum: Ophthalmic Optics

Just wondering whether an overcorrected cyl of -0.50DC will cause any significant problem to the patient if he continue to use the overcorrected spectacle? Here's the scenario: The patient's actual refractive power is -2.00/-1.25 x 180 but the spectacle he using is -2.00/-1.75 x 180 Does...

just had an rx check, previous PAL is from Lenscrafters. The markings were partially cut off nasally, all I could tell was a square box like Gradal RD on his old ones. so, new glasses are GT2, but he's not doing well with them. called LC and all they could tell us is its the "House Brand" PAL. ...

Dear all, Can somebody guide me if it is possible to obtain appropriate IPD (Distance) in Bifocal (Flat Top / Curve Top) lenses??? :confused: If yes, how to get it??? Your guidance will be very very helpful. kind regards Himanshu

Hey guys, I wanted to put this to you guys. I have done a little bit of research, but I wanted to know what you thought. There is a discrepancy between the effective power formula in a few books: In "System for Ophthalmic Dispensing" the formula reads: F_e = \frac{1}{\frac{1}{F_v} - d} ...

Hey there! This is kirby, a new comer. profession in eye optics. I wish i could get much progress via discussion in this forun. Enjoy the seeing

Hi guys and gals... Before I order a lens, is there a way to figure (approximately) how thick a lens edge will be AFTER the lens has been edged? I use the Opticampus thickness calculator, but am under the impression that the measurment I get is for the lens blank itself and I'm in need of a...

I posted this is the Optics section, but this seems like a more appropriate place to ask this question: Does anyone know a more exact way of calculating the power of cylinder in an oblique meridian other than the sine-squared approximation method: Fa = Fcyl sin(a)]^2 ? Or does the torsional...

Okay, so I wanna see how many people follow the "for every 2 degrees of tilt, lower the OC 1mm" rule. And my question is, why haven't I heard about this until studying for the Advanced NOCE. It, of course, makes some sense; but I've never seen anyone raise a pt's chin so that the frame front is...

I was just wondering how many OptiBoarders have taken the ABO's new Advanced Certification exam that replaced the old Master Optician exam? Any comments on the content and level of the questions? Best regards, Darryl

Does anyone have a wiring diagram for a Coburn 99 Blocker. I need to re-wire one that I just bought with the wiring all crossed up.

Hi guys, I live in Toronto/Pape. I do not know how can I travel to Waterloo University /school of Optometry .Please ,I urgently need a clear plan of transportation from point A to B.

Just a couple articles I ran across while doing some homework on light speed(s). ;) http://www.jupiterscientific.org/sciinfo/slowlight.html http://partners.nytimes.com/library/national/science/053000sci-physics-light.html

Hello forum, did anyone of you ever get this error code 0209 on your NIDEK 3D-fit LE-900 EX Express? I don't have the manual to look it out, the process just stops in the middle and I get that error message. Is there a link I can download the manual online? Any suggestion is appreciated. thanks ...

...achromatic doublet lens? Just thinking back to my much more active astro days, and wondered if anyone had been brave and tried working out any sort of viable achromat doublet type design in ophthalmic plastics as opposed to glass? Not sure if the weight/thickness would make them commercially...

Lately we have been having issues with a large amount of scratches skyrocketing our breakage percentage. We have tried many cloths and have finally settled on disposables which seem to have the best results. We use denatured alcohol as our primary cleaner. Any tips/tricks to reduce scratches would...

how can i make a telescope with ophthalmic lenses I have upto +20.00 or -20.00 lenses can any one tell me what power is required and the distance between 2 lenses Prince A.m Khan princeamk@yahoo.com 0092-321-2482418

hey all- ive recently been put in charge of a gerber lab. The generator the lab has is a Gerber sgx. I'm running into a few issues I cannot troubleshoot. With progressives, techs keep getting unwanted prism after the lenses are generated. I was wondering if there's a way to troubleshoot this....

We have an order for -19.00 for a two year old child:( . I would like to attempt grinding a biconcave in an attempt to 1)make it look a little better and 2) just plain make it easier, weve had problems in the past with higher powers flying off the finer even after adjusting the stroke down. My...

http://en.wikipedia.org/wiki/Negative_refractive_index It doesn't occur naturally, and admittedly, doesn't really have any practical application in ophthalmic optics, but it's pretty cool anyway. And, more inportantly, one of the Universities doing research into the subject is about 20...

The BSI or possible ANSI tolerance chart states that the prism tolerance is calculated upon the "lowest principal power of a pair of lenses" Example 2.00 -1.00 x 90 0.25 -1.00 180 If i was checking PD tolerance (horizontal) , i would take the lowest principal power which in this case...

Have 63 yr. old male who had cataract surgery 6 mos. ago. He has worn verticle prism of 9dn od and 9 up os. We have made plano rx lenses with the prism in frames for polycarbonate polarized sunglasses with a 5 base curve. He complains of less clarity in the right lens as worn. The lenses have been...

I'm trying to find out here which resist more, the best brand and which has no riscs for the eye.

If you run glass on this machine, you know that it is almost impossible to find diamond wheels. I'm working with Norton Diamond (who made the wheels for Coburn) to see if they would be interested in a production run of approximately 25 to 30 new wheels. I've also asked them to consider a...

Hi, Does anybody use dip coating machine from SCL and is able to do the AR with using of ion source with varnished lenses on any dip parameters? Many thanks Peter

Is there any possibility of someone getting a squint after refractive surgery because there will be changes to the accommodative state for the various distances, so the eye may turn in when previously it was straight. Also, after cataract surgery, is this again a possiblity? What level of...

Help! I have a patient that was in a five year old pair of Solamax polycarb progressive lenses (with ARC) with the following Rx: OD -0.50-1.25 x 57 OS -1.25-1.00 x 113 +1.50 add His Rx changed, and we put him into Physio CR-39 (he opted out of polycarb) with Alize ARC. His vision is...

Can anyone enlighten why i just can't get a sharp mires on the manual lensometer for some lenses like Polycarbonate?

Hello Eyecare Professional: Now is running a new website designed for opticians. In this page you can find laws, rules and code of ethics for opticians in Puerto Rico. I want to add more information about my profession and to have relations with other organizations, opticians, schools and...

So I have been racking my brain on this, how to convert decentration into lens tilt. d = decentration (mm) r = radius (mm) t = tilt t = tan^-^1(\frac{d}{r}) The value comes out a little high though, I have found that it should be about 3/4 of that value. I have put pencil to paper and...

Hello there i have my final exam coming up in 4 days time and was looking for some advice from some real professionals working in the wonderfield field of dispensing. Basically, there have been many parties and my brain is currently failing me in the area of bifocals and i cant seem to find...

Goodevening from Athens (Greece). Now I am studying the properties of the ophthalmic lenses (nontinted), and I can't find a mathematical function for the that property. From the Geometrical Optics is noted the relation: (transmission %+reflection%+absorption%=100%, for non monochromatic...

I am curious to know if it is possible to calculate the index of a lens if you only know the power, the front curve and back curve or do I need other information. Any help would be appreciated.

just curious to know ,why i see DIFFERENCE IN POWER on my Lensometer when i got my ordered lens from ZEISS ! I Ordered them -8.75 ( which reads -8.50 on Lensometer ) & -9.00 DS/-0.75 DC ( which reads -8.75 DS/-1.25 on Lensometer )..........The Lens is SV ZEISS 1.74 AS ! is it because of ASPHERIC...

Just to make sure im on the right track......another word for a lens that is coated in a manner to allow more light to pass through it is, "blooming"?