Ran into a term I dunno--can somone help please

**LauraH** · 05-24-2002, 08:47 PM

I just took the ABOC last weekend and I think I was pretty prepared for it. However, there was a term on the test I had never heard of before. I asked all the other opticians and lab techs at work and nobody knew what it was. My boss told me she thought they might have just slipped it in to try to confuse people. The only thing was it was the answer to 2 questions.

The term is STRAIE. If anyone knows what this means and can explain it to me I would be very grateful.

Thanks,
Laura

**stephanie** · 05-24-2002, 09:05 PM

Striae (correct me if I am wrong guys) I believe is a corneal problem usually associated with contact lenses. It is seen under the slit lamp and looks like vertical lines. You should hear a lot more about this when you prepare for the NCLE. Yes they probably put it on the test to confuse you. Although the claim has been they don't have any confusing questions I found quite a few of them very confusing.

Steph

**chip anderson** · 05-24-2002, 09:14 PM

You will remember from basic anatomy we have striated muscle. Striae in the cornea look like the little white striae around striated muscle. They aren't circular of course but look a little like linear stretch marks. In fact I once saw a woman in a painful stage of acute glaucoma whose cornea was stretched by the pressure to the point that it looked like over stressed cellophane (full of stria).

With treatment she did recover and same disappeared, the cornea cleared went back to near origional shape and was able to wear contact (PMMA) lenses thereafter.

She loved me for getting her ophthalmologist stat.

Chip.

**Darryl Meister** · 05-24-2002, 10:51 PM

I believe that striae is also a variety of imperfections within glass lenses, as well.

Best regards,
Darryl

**Jeff Trail** · 05-25-2002, 01:36 PM

Laura,

Darryl hit it on the button.. on the ABO test the question has to do with using a polaris scope? Is that the one you are talking about?... they wanted to get the answer, in this case the term is used to describe internal stress marks in the polarized sheet in a polarized lens :)
In Chip and Steph's answer it can also be used on the NCLE test when talking about biomicroscopy...

Jeff "just a lowly lab rat" Trail

**LauraH** · 05-25-2002, 02:27 PM

Yes, the question on the test had to do with lenses. I knew that polariscopes were used to check for imperfections in glass and plastic lenses but I didn't know the term for them was Striae. It is also very interesting to know that it can happen on the cornea. I am so glad I asked you guys. My entire office was stumped and most of the Opticians have 10-15 years experience.

Thanks,
Laura

**David Wilson** · 05-26-2002, 09:39 PM

Laura,
My understanding is the same as Darryl's, altthough I am sure that the other explanations are correct, particularly given Chip's explanation of the source of the term. The stria (the e is used to make the term plural) is due to an uneven refractive index within the glass and they appear as very fine veins inside the lens (rather than on the surface).
Regards
David

**Alan W** · 05-27-2002, 02:48 AM

The subject also relates to the unequal cooling of glass which led to striae and was detectable using polarization (i.e.polariscope or a colmascope) techniques AND was somewhat detectable holding the lens up to a light emitting grid.

**eyesguy** · 05-27-2002, 02:35 PM

Hi:

Striae is a common defect name used by plastic (and glass) lens manufacturers. It represents anything in the body of the lens that alters the index of refraction. It can appear as fingers, waves, blotches, etc. If bad enough, it can be detectected visually. It can easily be detected using an arc lamp. If it's near the center, it might show up as a distortion in the lensometer. And, if it is on or near the surface, it can cause a dye defect. A common source of striae is plasticizer leeching in from the gasket used to mold plastic lenses. Striae is not a stress related defect and will not usually show up on a polariscope

Regards,

eyesguy

**chip anderson** · 05-27-2002, 05:45 PM

While this will show up stresses and imprefections in plastic blanks and finishied lenses (including contact lenses). It's main origional use in the optical industry was to see if the eyewire or drill mounting screws placed undue stress on the lens. When opticians were more than they are today, one would hand edge the lens until no stresses were present. If stresses were present on glass (especially untemptered and dress hardened lenses) they would chip from the bumps of everyday life, sometimes with no bumps.

Chip

**LauraH** · 05-28-2002, 10:48 PM

So, I just want to make sure I am understanding this fully. Striae, as refering to spectacle lenses, is imperfections within the lens from the manufacturing process. It can show as lines or waves etc. And is actually in the lens. You can sometimes see them holding the lens to light if they are bad enough and can usually see them with an arc lamp otherwise. They can sometimes be seen with a polariscope but the polariscope is intended to be used to check more for strain then for striae.

Laura

**eyesguy** · 05-29-2002, 08:10 AM

LauraH:

You got it! The important thing is the defect is not physical in the sense that it is a scratch, chip, etc. Rather, it is a localized area in the lens where the index of referaction is different

eyesguy

**Darryl Meister** · 05-29-2002, 10:01 PM

Yes, I think it's probably important to point out that the word can have different meanings depending upon the context. The word stria, itself, means, "a stripe or line distinguished from the surrounding area by color, texture, or elevation." Consequently, the word is used in many applications.

Best regards,
Darryl

**Texas Ranger** · 05-30-2002, 11:15 AM

Laura, sometimes, a job will be dispensed and the pt is back in a day or two, complaining about an area of the lens that at a certain angle, under certain light situations, will cause part of the image they're looking at to blur...(we can't 'see' it), sometimes we would call it a 'wave'....just have it remade....it'll solve the problem, btw, seems to be a bigger problem in in-house molded lenses...

**Katheryn Schram** · 06-05-2002, 10:25 AM

Striae is the plural form of a word you are probably familiar with: STRIA.
Stria is a lens defect. It's a "streak" in the lens where the index of refraction varies.

**tmorse** · 07-09-2002, 05:35 PM

Very faint lines in a finished lens...considered a lens defect...replace lens

**Need2focus** · 10-16-2002, 08:37 PM

Hello, everyone. You may already have an understanding of Striae, but I have an acgtual definition form a Lens Theory course as it relates to glass lenses. Striae- fine streaks or veins in the glass itself---caused by insufficient mixing and stirring of raw materials.

We were told in class that we may see this on the ABO, but the term isn't primarily used much in the field. Most will just say it is a manufactures defect.

need2focus