Podcast
Questions and Answers
What is the purpose of a keratometer?
What is the purpose of a keratometer?
- To measure the refractive index of the cornea
- To determine the axial length of the eye
- To directly measure the dioptric power of the cornea
- To convert the radius of curvature to the dioptric power of the cornea (correct)
What is the range within which a keratometer can measure corneal curvature without the need for auxiliary lenses?
What is the range within which a keratometer can measure corneal curvature without the need for auxiliary lenses?
- 44.00D to 60.00D
- 36.00D to 52.00D (correct)
- 30.00D to 56.00D
- 20.00D to 45.00D
What is a limitation of keratometry mentioned in the text?
What is a limitation of keratometry mentioned in the text?
- It can only measure corneal curvature in a small region of the cornea (correct)
- It ignores spherical aberrations
- It does not provide accurate measurements for eye axial length
- It measures the cornea only at one particular radius
What error can result from incorrect focusing while using a keratometer?
What error can result from incorrect focusing while using a keratometer?
How should the procedure for using a keratometer begin?
How should the procedure for using a keratometer begin?
What should be done to the principal meridians while using a keratometer?
What should be done to the principal meridians while using a keratometer?
What is a consequence of ignoring spherical aberrations in keratometry?
What is a consequence of ignoring spherical aberrations in keratometry?
What should be overlapped with the horizontal meridian wheel in keratometry procedures?
What should be overlapped with the horizontal meridian wheel in keratometry procedures?
What should be aligned with the vertical meridian wheel?
What should be aligned with the vertical meridian wheel?
When observing corneal integrity, what should be evaluated?
When observing corneal integrity, what should be evaluated?
What is the recommended action if irregular astigmatism is present?
What is the recommended action if irregular astigmatism is present?
Which type of astigmatism is characterized by principal meridians being perpendicular?
Which type of astigmatism is characterized by principal meridians being perpendicular?
In With-the-rule (WTR) Astigmatism, where is more power located?
In With-the-rule (WTR) Astigmatism, where is more power located?
How should one proceed after evaluating the right eye (OD)?
How should one proceed after evaluating the right eye (OD)?
What is recorded with an amount of corneal astigmatism in diopters and an axis of -1.13x180?
What is recorded with an amount of corneal astigmatism in diopters and an axis of -1.13x180?
In which type of astigmatism do principal meridians not form a 90-degree angle?
In which type of astigmatism do principal meridians not form a 90-degree angle?
What should you do if you are unable to locate keratometric mires?
What should you do if you are unable to locate keratometric mires?
What can cause transient mire focus issues?
What can cause transient mire focus issues?
How can extended ranges be achieved in keratometry?
How can extended ranges be achieved in keratometry?
What should be done if only 1 plus sign is visible during measurement?
What should be done if only 1 plus sign is visible during measurement?
When might a patient have irregular astigmatism affecting H&V mires measurement?
When might a patient have irregular astigmatism affecting H&V mires measurement?
What action should be taken if only 1 minus sign is visible during measurement?
What action should be taken if only 1 minus sign is visible during measurement?
What are the corrective factors for increasing and decreasing diopter range in keratometry?
What are the corrective factors for increasing and decreasing diopter range in keratometry?
For K readings above 52.00D, what should be added to extend the range?
For K readings above 52.00D, what should be added to extend the range?
What is the correct true K value when the K reading is 49.00D and a +1.25D lens is added in front of the barrel?
What is the correct true K value when the K reading is 49.00D and a +1.25D lens is added in front of the barrel?
What is the formula used to calculate the true K value after adding a corrective lens in front of the barrel?
What is the formula used to calculate the true K value after adding a corrective lens in front of the barrel?
How should mires be recorded in cases of irregular and distorted shapes?
How should mires be recorded in cases of irregular and distorted shapes?
What is the expected angular separation between the 2 principal meridians in astigmatism?
What is the expected angular separation between the 2 principal meridians in astigmatism?
For astigmatism, what is the average range for K readings according to the text?
For astigmatism, what is the average range for K readings according to the text?
When adding a -1.00D lens in front of the barrel, what is the new K drum reading if the initial K reading is 38.00D?
When adding a -1.00D lens in front of the barrel, what is the new K drum reading if the initial K reading is 38.00D?
What is Javal's Rule primarily focused on determining?
What is Javal's Rule primarily focused on determining?
In recording corneal cylinder (CC) data, what are the steps used for each line in the dial in diopters?
In recording corneal cylinder (CC) data, what are the steps used for each line in the dial in diopters?
What will be the refractive astigmatism when the corneal curvature is -2.00 @ 090 using Javal’s rule?
What will be the refractive astigmatism when the corneal curvature is -2.00 @ 090 using Javal’s rule?
If the total refractive astigmatism is -1.00 x 180, what will be the result after applying the Simplified form of Javal’s Rule?
If the total refractive astigmatism is -1.00 x 180, what will be the result after applying the Simplified form of Javal’s Rule?
For a corneal curvature of 43.00 @ 180 and 46.00 @ 090, what is the total refractive astigmatism using Javal’s rule?
For a corneal curvature of 43.00 @ 180 and 46.00 @ 090, what is the total refractive astigmatism using Javal’s rule?
When the corneal curvature is -0.50 @ 090, what will be the predicted total refractive astigmatism using the Simplified form of Javal’s Rule?
When the corneal curvature is -0.50 @ 090, what will be the predicted total refractive astigmatism using the Simplified form of Javal’s Rule?
For a corneal curvature of -1.00 @ 090 and applying Javal’s rule, what would be the total refractive astigmatism?
For a corneal curvature of -1.00 @ 090 and applying Javal’s rule, what would be the total refractive astigmatism?
If the corneal curvature is -2.00 @ 180, what will be the predicted total refractive astigmatism using the Simplified form of Javal’s Rule?
If the corneal curvature is -2.00 @ 180, what will be the predicted total refractive astigmatism using the Simplified form of Javal’s Rule?
What will be the refractive astigmatism when the corneal curvature is -2.00 @ 090 according to Grosvenor et al?
What will be the refractive astigmatism when the corneal curvature is -2.00 @ 090 according to Grosvenor et al?
When you have a corneal curvature of -1.50 @ 180 and apply Javal's rule, what is the total refractive astigmatism?
When you have a corneal curvature of -1.50 @ 180 and apply Javal's rule, what is the total refractive astigmatism?
