MISC information related to NCLE/CLRE Flashcards
Taco test
One way to tell if your lens is right side out is to look at the profile by putting the lens on the tip of your finger and holding it at eye level. It should be bowl-shaped. If the edges turn downward slightly forming a lip, the lens is inside out and must be reversed. With a little practice, you’ll see an obvious difference.
Another way to find the right side is to use the “taco test.” Hold the lens between your thumb and index finger and apply gentle pressure. The edges should fold toward each other like a taco. If the edges don’t fold easily or if they turn outward toward your fingers, the lens is inside out. if you have ultra-thin lenses, the taco test may not be reliable.
You can usually tell if a lens is inside out by the way it feels on your eye. It won’t be comfortable and will probably move a lot when you blink. Your vision won’t be as sharp and clear; either. Just remove the lens and turn it right-side-out. You may have the same sensations if you put a lens in the wrong eye; so always work with one lens at a time, keeping the other lens in the lens case with the cap on.
If you remove the lens from your eye or if it blinks out or folds as you place it on your index finger, put the lens in the palm of your hand and soak it with the preserved saline solution that comes with your system. Then touch the lens gently until it regains its bowl shape.
S.O.A.P
Subjective, Objective, Assessment, and Plan
Cross cylinder examination (otherwise known as Jackson’s cross cylinder)
Cross cylinder examination (otherwise known as Jackson’s cross cylinder) is an examination used for the final fine-tuning of the axis and strength of astigmatism after its determination through retinoscopy, stellate cycle or automatic refractometry. With the advent of technology, techniques like retinoscopy and cross cylinder examination might seem outdated and useful only to the personnel of humanitarian missions. They do however provide an accurate alternative and their use gives a thorough understanding of the principles of refraction.
Refer to the following video link:
https://www.youtube.com/watch?v=hMusaIvTLVo
The duochrome or bichromatic test
The duochrome or bichromatic test is commonly used as a check on the best vision sphere during monocular refraction. It can be used at two points:
After the initial determination of the best vision sphere and prior to the use of the Jackson cross-cylinder (JCC) - to ensure the circle of least confusion is on the retina prior to the use of the JCC.
After the JCC test and prior to finalizing the refractive correction.
Duochrome test procedure
- Occlude one eye. Turn off the room lights to dilate the pupil, which increases the chromatic aberration of the eye.
- Ask the patient: “Are the rings/letters/dots clearer and backer on the red or on the green, or are they the same?” If they are the same, this suggests the vest vision sphere has been obtained and the circle of least confusion is on the retina.
- If the rings on the green are clearer, add plus +0.25 DS until you obtain balance. Note the additional spherical power needed to obtain balance.
- If the rings on the red look clearer, add minus -0.25 DS until you obtain balance, noting the additional power required.
- If more than +/- 0.50 DS is required to balance, this usually indicated the duochrome test is not reliable for this patient and should be ignored.
- Prior to the use of the JCC: if the clarity of the rings changes from green to red with +0.25 DS or from red to green with -0.25 DS, then leave a young patient on the green as they will be able to accomodate to bring the circle of least confusion onto the retina.
- After the use of the JCC and before finalising the refraction: if the clarity of the rings changes from green to red with +0.25DS or red to green with -0.25 DS, note the additional spherical power required t leave a young patient ‘on the red.’
- Use the additional lens power suggested by the duochrome test and double-check whether this additional power is preferred by the patient using the plus-minus technique of best vision sphere assessment.
Other topics and questions covered on the NCLE/CLRE. (Some of these may not be very clear, I will elaborate on these topics when I’ve done some research and get a chance)
What lens fits this prescription? toric, bitorc, etc?
V-slot gauge
A ruby red contact lens would be used for what?
A patient calls a day after complaining about (insert random symptoms) what do you do?
Tricurve lens
Biospheric lens
Bennet’s rules
An individual with brown eyes wants colored contacts. What type of contact lens does he need to make his iris color appear blue?
Initial appointment frequency for various contact lens wearers in the initial stage. Like how often should a first-time user of full-time contact lenses return for a checkup?
Saggital depth
If a lens is rotated by a certain amount of degrees in a certain direction, how do we adjust the new prescription?
Over refract, find the power
A patient’s lens arrives from the lab and they do not match the prescription. What degree of error in these lenses would still be acceptable? I.E. the prescription base curve is __ and the arrived contact lenses are a different value, would they fall in an acceptable degree of error?
If a patient had an artificial lens inserted, what would you expect to see in a slit lamp?
Resources for further learning - NCLE/CLRE. HIGHLY RECOMMENDED you study this.
Two sets of notecards with valuable information covered on the NCLE/CLRE
NCLE prep - a set of 60+ Brainscape notecards. The link is provided below.
https://www.brainscape.com/packs/ncle-prep-13289208
Contact Lens Exam 1: Basic Contact Lens Principles - a set of about 50 Quizlet notecards. The link is provided below.
https://quizlet.com/193545507/contact-lens-exam-1-basic-contact-lens-principles-flash-cards/.
Optional, but you may want to get a copy of this book: CLRE Secrets Study Guide: CLRE Exam Review for the Contact Lens Registry Examination. Link to the book is provided below.
https://www.mo-media.com/clre/
