Contact Lens Education

[Joann Raytar]

Originally posted by stephanie:
Ah Chip!! I believe me book has some wrong answers. I have for the answers both as being B. Hmmmm... interesting.

Steph,

Chip is right about the answers to your examples. (45.00D =7.50mm) Do you remember how a couple of us told you how to convert Base Curves to Diopters?

[Joann Raytar]

Contact Lens Master Chip:

Starting the thread was a good idea! I mentioned in another post that I was returning to an independent shop; now I won't have to start a whole new thread when I come running to you for advice. It is nice to see that you speak from experience not just a text book. There is too little of that type of knowledge these days.

Jo

[Joann Raytar]

Chip:

We get alot of people, especially teenagers, who come in looking for non-Rx cosemetic lenses. We also get alot of expired contact lens Rx's in. Both will get into a shouting match and say they have gotten lenses in other cities without exams or fittings. Short of tossing one of your glass eyes at them, how do you effectively deal with them; they kind of ignore the medical device speech? I know you a good with words and I am looking for optical "fire and brimstone" here.

[Maria]

I know you addressed this to Chip, but with the teenagers I would try pointing out that no-one will fancy them (or whatever the US term is) when they are blind and their eyes are all starey and strange. Use the word 'disabled', as it has good psychological impact. Tell them that you couldn't care less if they go blind, but they're not doing it in your shop. Teenagers can relate to people who couldn't care less :) And shout loudly, because your're older than them and you can.

[Sara]

In fitting of RGP lenses we are taught that lens diameter is important to obtain good centration,base curve is not mentioned.
Sara,
Optical Student(2nd year)

[Sara]

Uncle Chip,
Shabbir asked your view on importance of lens diameter versus base curve in relation to RGP fitting parameters.
You replied base curve.
Shabbir expressed his view that he considers diameter an important parameter in RGP fittings.
You answered him with he is all wet(LOL).
In your later tread posting you said"as to base curve vs diameter they both make up 1/2 of the specification sagital depth and to have an imbalance of either would make them both wrong"
This means in principal you agreed that diameter is important fitting parameter of RGP lenses.
So you were wrong in first place when you replied him that base curve is important parameter in RGP fitting.
You are confusing me uncle!

Your (dry) niece Sara

[chip anderson]

Sara: I replied that the diameter being the most important concideration was wrong. I did not say it was not important. As you will note I don't think any parameter is unimportant, but if I were forced to say which was most important I would say the relationship of the base curve to the cornea, period.

You may have your parameter that you think is most important, you are entitled to this, as I am entitled to disagree.

[This message has been edited by chip anderson (edited 03-06-2001).]

[Sara]

Can someone please explain me in simple english
Cell Mitosis
Dk
Dk/t
I find it difficult to grasp from textbooks.
Sara

[Sara]

Uncle Chip,
You seem to be upset,that's the reason you not coming up with answers on questions posted in above tread.
Sara

[shanbaum]

Originally posted by Sara:
Can someone please explain me in simple english
Cell Mitosis
Dk
Dk/t
I find it difficult to grasp from textbooks.
Sara

Cells reproduce in two ways, mitosis, in which case a cell divides in two so as to produce two cells, each with the same chromosomes as the parent; and meiosis, which results in two cells each having half the parents' chromosomes.

In simple English: mitosis is cell reproduction by division.

Dk is a measure of the ease with which oxygen can be dispersed (or "diffused")through a material. Dk/L (and I suppose, DK/t) is similar; it's a measure of the actual transmission of oxygen through a material of a given thickness.

"D" is the "diffusion coefficient" and "k" is the "solubility coefficient". Since I don't know how this measurement is actually done, I can't describe these. But "diffusion" and "solubility" seem pretty descriptive.

Regarding Uncle Chip (thank you for that) and the diameter v. base curve issue: I too would regard base curve as the more useful and critical fitting parameter. You can't change the diameter nearly as much as you can the curve, and changing the curve has a more direct and predictable effect on the fit.

That said, I'd rather make bricks without straw than fit contact lenses.

[This message has been edited by shanbaum (edited 03-09-2001).]

[Sara]

Dear Uncle Shanbaum,
Thank you very much for your simple explaination.It was easy to understand.
Regarding Diameter VS Base curve in RGP fittings,I am going to write to my course tutor and association to find it out more.If Shabbir being an international lecturer on cornea & contact lenses does not know simple things like this,I will stop him from coming to Kenya to lecture on this subject.I know Shabbir because we are from same region,Kenya,Uganda and Tanzania makes East-Africa.I have attended couple of his recent presentations in Addis Ababa,Ethopia.He is research optometrist.Now time has come for him to make bricks.
Thanks again uncle.

Sara
optical student


[This message has been edited by Sara (edited 03-09-2001).]

[chip anderson]

Dearest Sara: I was no upset, I had a page in an old "dictionary of Science" that Illustrates cell division in all four stages. Didn't remember the names and particulars enough to send you a popped off answer. Still haven't located the book, but If and when I will E.Mail it to you.

Chip

[chip anderson]

Finally getting back to this thread.

Methods of detecting corneal edema.
1) Observation in slit-lamp best seen with retro (light bounced off iris) illumination.
2) Central clearance (or sometimes more obscure areas) deminished under flourcein.
3) Changes in "K" readings from origional pre-fit condition.
4) Patient symtoms:
1)Spectacles seem fuzzy on removal of contacts.
2) Photophobia (sunlight sensitivity) should not be persent in a "perfect fit" of any type contact.
3) Over wearing syndrome, ( pain or discomfort sometime (30 min to several hours) after removal of lenses.

Recommendation: Check all of the above and do something about it if significantly changed at any follow-up. For the most part these things should not change at least on the short term. It is true that as one goes from teenager to middle age+ the cornea is likely to move from with the rule to against the rule cylinder and average corneal radii are somewhat longer, but these should not be short term (less than one decade) changes.

Chip

[Optom]

Hi Sara,
Re-visiting this post.Did you get correct answer from your course tutor you were going to ask about silly but important arguement on RGP=Diam. Vs BC.
I always want to re-learn and want remain student througout my life though however qualified I am!
Your Uncle Chip is qualified & experienced contact lens technician as I have noticed from reading his postings.However,he is arguementative by nature.I appreciate his knowledge in optics.
Shanbaum has no intellect.All his postings I have read;either he pleases posters by putting little flavoured remarks,or copy- repeats the same.
If feel he is here to do postings to increase his optiboard points only.Honestly Sara,you despite being still student,you have better knowledge of optics than Shanbaum.

[Sara]

Dear Shabbir,
Yes, I did get correct answer from my tutor,but I don't like academic conflicts.Both of you are right,OK.
Thanks for the compliments too.
Thanks,
Sara