Tonometry MCQ Quiz | Clinical Skills & Procedures

Welcome to the Tonometry MCQ Quiz, an essential module for MBBS students focusing on Clinical Skills & Procedures. This quiz is designed to rigorously test your understanding of the principles, techniques, and clinical applications of intraocular pressure measurement. You will encounter 25 multiple-choice questions covering topics from the foundational Imbert-Fick law to the practical nuances of Goldmann, Schiøtz, and non-contact tonometers. Assess your knowledge on indications, contraindications, sources of error, and result interpretation. Upon completion, you can submit your answers to receive your score and a detailed review of your performance with correct answers highlighted. For your future reference and study, an option to download all questions and their correct answers in a PDF format is also available.

1. The Goldmann Applanation Tonometer (GAT) operates based on which principle?

The Pascal Principle

The Imbert-Fick Law

The Bernoulli Principle

The Maklakoff Principle

2. What is considered the normal range for intraocular pressure (IOP) in the adult population?

5-10 mmHg

10-21 mmHg

22-30 mmHg

30-40 mmHg

3. A thicker Central Corneal Thickness (CCT) is known to cause what kind of error in Goldmann tonometry readings?

A falsely low IOP reading

A falsely high IOP reading

No significant effect on IOP reading

Variable and unpredictable readings

4. The Schiøtz tonometer is an example of which type of tonometry?

Applanation tonometry

Indentation tonometry

Non-contact tonometry

Dynamic contour tonometry

5. Which of the following is an absolute contraindication for performing contact tonometry?

Glaucoma

High myopia

Active corneal ulceration

Cataract

6. What is the ideal appearance of the fluorescein mires at the endpoint of a Goldmann tonometry measurement?

Two semicircles widely separated

Two semicircles overlapping completely

The inner edges of the two semicircles are just touching

The outer edges of the two semicircles are touching

7. Non-contact tonometry (NCT) or “air-puff” tonometry estimates IOP by measuring:

The force required to indent the cornea

The time taken for a puff of air to flatten a specific area of the cornea

The electrical resistance of the corneal surface

The acoustic reflection from the anterior chamber

8. Which local anesthetic is most commonly used prior to contact tonometry?

Lidocaine 2%

Bupivacaine 0.5%

Proparacaine 0.5%

Cocaine 4%

9. What is the standard diameter of the corneal area flattened by a Goldmann tonometer?

1.55 mm

2.54 mm

3.06 mm

4.00 mm

10. The Perkins tonometer is best described as a:

Type of Schiøtz tonometer

Non-contact “air-puff” device

Portable, handheld version of the Goldmann tonometer

Digital indentation tonometer

11. If the fluorescein mires in GAT are too thick or wide, what is the most likely cause?

Insufficient fluorescein

Excessive fluorescein or a very wet cornea

High corneal astigmatism

The tonometer is not perpendicular to the cornea

12. Which of the following factors can cause a transient INCREASE in intraocular pressure?

General anesthesia

Vigorous exercise

Valsalva maneuver

Sleeping in a prone position

13. The Tono-Pen is particularly useful in which clinical scenario?

Routine screening in a busy clinic

Measuring IOP over a soft contact lens

Bedside measurements and on scarred or irregular corneas

Research requiring highest precision

14. What is the recommended method for disinfecting the Goldmann tonometer prism tip between patients?

Rinsing with tap water

Wiping with a dry tissue

Soaking in 70% isopropyl alcohol or using a hydrogen peroxide wipe

Autoclaving the prism

15. High regular corneal astigmatism (>3 Diopters) can affect GAT readings. How is this error minimized?

By taking an average of two readings, one with the prism horizontal and one vertical

By increasing the amount of fluorescein

By using a non-contact tonometer instead

By applying more pressure with the tonometer

16. The pulsatile movement of mires seen during GAT corresponds to:

The patient’s respiratory cycle

The ocular pulse (cardiac cycle)

Small movements of the patient’s head

An artifact of the slit lamp illumination

17. Which tonometer is less affected by corneal properties like thickness and biomechanics compared to GAT?

Schiøtz tonometer

Perkins tonometer

Non-contact tonometer

Dynamic Contour Tonometer (DCT)

18. A potential iatrogenic complication of performing contact tonometry is:

Corneal abrasion

Posterior capsular opacification

Retinal detachment

Induction of astigmatism

19. Schiøtz tonometry readings can be significantly inaccurate in eyes with abnormal:

Pupil size

Lens thickness

Scleral rigidity

Vitreous humor viscosity

20. What is the primary purpose of the cobalt blue filter on the slit lamp during Goldmann tonometry?

To reduce patient discomfort from bright light

To excite the fluorescein dye, causing it to glow green

To better visualize the corneal surface and epithelium

To sterilize the tonometer prism tip

21. A patient with a thin cornea (e.g., post-LASIK) is likely to have a GAT reading that is:

Falsely high

Falsely low

Unaffected by corneal thickness

Unmeasurable

22. The force applied by the Goldmann tonometer is measured in grams. The reading on the dial is converted to mmHg by:

Multiplying the gram force by 10

Dividing the gram force by 10

Multiplying by 1.33

The reading is directly in mmHg

23. Holding one’s breath or a tight collar can artifactually raise IOP readings. This is primarily due to:

Increased sympathetic stimulation

Corneal dehydration

Increased episcleral venous pressure

Decreased aqueous outflow

24. Which tonometer would be most appropriate for a mass screening event for glaucoma?

Goldmann Applanation Tonometer

Schiøtz Tonometer

Non-Contact Tonometer (NCT)

Perkins Tonometer

25. The Imbert-Fick Law (P = F/A) assumes the cornea is:

A thick, rigid sphere

An infinitely thin, perfectly flexible, and dry membrane

Hydrated and has significant surface tension

A non-uniform, viscoelastic structure

Tonometry MCQ Quiz | Clinical Skills & Procedures

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