Welcome to the first CET Extra brought to you by Optician Direct. This is a new occasional series of CET modules in addition to the CET in Optician.
Prescription Interpretation - Avoiding the pitfalls
A Visual Recognition Exercise in Record keeping
C9794, "Prescription Interpretation - Avoiding the pitfalls."
2 general CET points for optoms and DOs
In this CET exercise which is an adjunct to our ongoing series on dispensing in Optician Journal, Andrew Keirl asks questions on the interpretation of record cards. The aim is to encourage everyone to be better able to specify the sort of information required to ensure a successful appliance and to avoid potential pitfalls and prescription intolerance. There are 3 prescription cards to look at, each with 4 associated questions. A score of 8 or more correct answers out of 12 gains 2 CET points.
All the questions are in this email. To complete the exercise and be registered for your points, please go to Opticianonline.net/eLearning/List and take the test. (If this is the first time you have taken part in any Optician CET module, you will need to become a registered user on opticianonline.net before you can enter the test module.)
Deadline for receipt of the answers is midnight on 14th November, 2008. Please note that points are uploaded to www.cetoptics.com up to one month after the deadline for a module
Andrew Keirl FBDO, MCOptom was a lecturer in ophthalmic dispensing at Anglia Ruskin University and is now running his own practice in Cornwall. He has lectured and written widely, mainly on lens related matters.| Record 1 |
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Question 1  |
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| This prescription is an example of? | ||
| A | Compound myopic astigmatism | |
| B | Simple myopic astigmatism |
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| C | Mixed astigmatism |
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| D | Irregular astigmatism | |
| Question 2 | ||
| What essential item is missing from this prescription? | ||
| A | Base curve of the lenses | |
| B | Unaided vision | |
| C | Interpupillary distance | |
| D | Vertex distance | |
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| Question 3 | ||
| It is likely that this prescription will be dispensed using a lens material with a high or very high refractive index. This will result in transverse chromatic aberration occurring when the wearer looks through off-axis points on the lens. Which of the following will not assist in keeping the effects of TCA to a minimum? | ||
| A | Fitting the spectacle frame with as small a vertex distance as possible. | |
| B | The use of best form lens designs. | |
| C | The use of materials with a low V-value. | |
| D | The application of correct horizontal and vertical centration and pantoscopic tilt. | |
| Question 4 | ||
| Which of the following statements is not correct? |
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| A | Ring diplopia is an uncommon complaint from high myopic patients. | |
| B | A 44 year old medium to high myope might enjoy more comfortable near vision in spherical as opposed to aspheric lenses. | |
| C | The Rodenstock Lentilux lens is suitable for high myopic prescriptions. | |
| D | A lens manufactured using a low refractive index material will always weigh less than the same lens manufactured using a very high refractive index material. | |
| Record 2 |
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| Question 1 |
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| Assuming that the near visual points are located 10 mm below the distance optical centres, the vertical differential prismatic effect produced at the near visual point will be: | ||
| A | 2∆ base down left | |
| B | 2∆ base down right |
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| C | 5∆ base down right |
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| D | 3∆ base down left | |
| Question 2 | ||
| Which of the following lens options is not suitable for controlling vertical differential prism? | ||
| A | A bi-prism bifocal lens used in combination with a standard bifocal lens | |
| B | Round downcurve bifocal segments of unequal diameters | |
| C | A solid prism segment bifocal used in combination with a standard bifocal lens | |
| D | Unequal diameter flat-top bifocal segments | |
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| Question 3 | ||
| If round downcurve bifocal segments of unequal segment diameters were used to control the vertical differential prism produced at the near visual point in prescription 2, which of the following options is most suitable? | ||
| A | Right R38 Left R28 | |
| B | Right R38 Left R22 | |
| C | Right R24 Left R45 | |
| D | Right R45 Left R24 | |
| Question 4 | ||
| Which of the following lenses would meet the no-jump requirement of prescription 2? |
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| A | An E-type segment bifocal | |
| B | A bi-prism E-type segment bifocal | |
| C | A flat-top segment bifocal | |
| D | A round segment bifocal | |
| Record 3 |
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| Question 1 |
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| The above distance prescription is to be made using single vision aspheric lenses. Which of the following statements is incorrect? |
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| A | An aspherical surface introduces surface astigmatism in order to neutralise the aberrational astigmatism associated with flat form lenses |
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| B | Aspheric lenses are thinner than their spherical equivalents | |
| C | Aspheric lenses are flatter than their spherical equivalents |
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| D | Aspherical surfaces reflect less light than their spherical equivalents |
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| Question 2 | ||
| The patient in prescription 3 is to be dispensed with a pair of +5.00 D aspheric lenses for near vision. The required near centration distance is 29 mm right and left. The frame to be dispensed has a boxed centre distance of 66 mm and a box lens size of 48 x 42 mm. When the patient’s head is in the primary position, the pupil centres have a height of 23 mm and the pantoscopic tilt is 8°. Which of the following will give exact centration? | ||
| A | Decentre both lenses 4 mm in from the box centre. Place the optical centre 2 mm above the horizontal centre line. Apply 6° of dihedral angle to each lens. | |
| B | Decentre both lenses 4 mm in and 4 mm down from the box centre. |
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| C | Decentre both lenses 4 mm in from the box centre. Place the optical centre 2 mm below the horizontal centre line. | |
| D | Decentre both lenses 4 mm in from the box centre. Place the optical centre 2 mm below the horizontal centre line. Apply 6° of dihedral angle to each lens. | |
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| Question 3 | ||
| The patient in prescription 3 is dispensed a pair of progressive lenses for general use. Bearing in mind his occupation, which of the following lenses would be a useful additional pair of spectacles? | ||
| A | Single vision reading lenses | |
| B | Single vision lenses for intermediate use | |
| C | An enhanced reading lens | |
| D | An “office” type lens | |
| Question 4 | ||
| The patient in prescription 3 is dispensed with a pair of Hoya Workstyle 200 lenses. Which of the following powers would be ordered? |
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| A | +3.00 DS Add +2.00 D |
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| B | +3.00 DS | |
| C | +5.00 DS |
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| D | +3.50 DS Add +1.50 D | |
NOW TAKE THE TEST! Click here to go through to Opticianonline's CET page where you need to find the matching test module. If you experience any difficulties taking part in this CET module, please contact Kay Hevey. |
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