FREE AND STUDY GAMES ABOUT KERATOMETRY EXAM

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FREE AND STUDY GAMES ABOUT KERATOMETRY EXAM

QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -28 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: Define Keratometry

Answer:

it means literally "measurement of the eye" Question 2: How should measurements be gotten in the case of irregular astigmats?

Answer:

For quantitative evaluation for irregular astigmatism corneal topography is used

Question 3: Define Oblique astigmatism

Answer:

The principle meridian with the greatest curvature is greater than 30 degrees from either 180 or 090

Question 4: What are 8 sources of error in keratometry

Answer:

1.imprpr calibration 2.imprprly focsed eye pc 3.faulty postning of patnt 4.lack of prpr fixatn by patnt 5.rdcd VA of examner 6.accmdtv fluctuation of examner 7.loclized corneal dstrtions 8.imprpr focusng of mires(espclly vertical)

Question 5: Define ATR astigmatism

Answer:

The principle meridian with the greatest curvature (and power) is horizontal or X090

Question 6: Define irregular astigmatism

Answer:

The principle meridians are not 90 degrees apart (note that this has no bearing on WTR or ATR classifications)

Question 7: What is Javal's formula for ETA?

Answer:

1.25dK + (-0.50X090)

Question 8: Name 4 types of instruments that can be used to perform keratometry

Answer:

1.Keratoscope (illuminated placido's disk) 2.2-position keratometers(the original manual models) 3.One-position keratometers(the most commonly used manual model & the ones that we use) 4.automated keratometers

Question 9: How could one measure the periphery of the cornea?

Answer:

Using a corneal topographer and unicorns

Question 10: Give four features of recordings of keratometry findings

Answer:

1.Horizontal meridian recorded first, vert second 2.recorded as power (not radius) found @ the measured meridian (not axis) 3.Recorded to the nearest .12D using three digits for the meridian 4.comment on mire quality if not clear and regular

Question 11: What does a keratometer measure?

Answer:

The radius of curvature of the central cornea's anterior surface.

Question 12: How is posterior corneal curvature figured into Javal's rule?

Answer:

It isn't. Posterior corneal curvature usually does not significantly contribute to total toricity.

Question 13: What is the ETA of an oblique astigmat?

Answer:

just: 1.25dK

Question 14: Define WTR astigmatism

Answer:

The principle meridian with the greatest curvature (and power) is vertical or x180

Question 15: Define regular astigmatism

Answer:

the principle meridians are 90 degrees apart (note that this has no bearing on WTR or ATR classifications)

Question 16: What are four clinical uses for keratometry?

Answer:

1.for refractive ETA & axis of astig 2.contact lens evaluations 3.assmsnt of opticl intgrty(qulty of cornea&tear flm) 4.diagnosis/eval of progressve optcl condtns (kertoconus)

Question 17: What area of the cornea is measured in keratometry?

Answer:

1.the mire is NOT reflected of the exact center of cornea 2.reflctd from 2 small areas on either side of the axis of the instrument 3.reduem of curvature is measured from this small area about 3mm in diameter

Question 18: What is the average K reading

Answer:

43.00 to 44.00

Question 19: What type of procedure is keratometry?

Answer:

an objective refractive assessment technique in which refractive status is determined w/o input from the patient

Question 20: How is keratometry used in contact lens evaluations?

Answer:

1.msrmnt of crvtr for fittng contcts 2.montring corneal damg secndry to contct wear 3.msrmnt of flexure of RGP's on eye 4.msrmnt of radius of crvtr of both soft & RGP's

Question 21: Why is the dK not the same as total astigmatism?

Answer:

1.spectacle lens effectvty of 13mm is not considred 2.K's only measure the ant corneal surface 3.the back of the cornea can also be toric leading to internal astigmtsm 4.does not figure in lenticular astgmtsm due to natrl tlting of lens

Question 22: How does (broadly) a keratometer work?

Answer:

1.cornea & tear film form a convex mirror 2.keratmr reflects obj of known size from known disnc off of cornea 3.size of relctd img is measured 4.estimtd refrctng pwr of crnea is calctd

Question 23: What is anisometropia? What is antimetropia?

Answer:

1.The two eyes have different refractive powers 2.One eye is myopic and the other is hyperopic

Question 24: What is an alternative name for keratometry?

Answer:

Opthalmometry. It also means "measurement of the eye" but is less accurate and less commonly used

Question 25: When is keratomerty usually done (on which patients)?

Answer:

New patients, all contact lens patients & when indicated by history/symptoms

Question 26: Define principle meridians

Answer:

The 2 meridians of greatest & least curvature

Question 27: What does the -0.50x090 used in Javal's rule account for?

Answer:

The presence of lenticular astigmatism