IJCAHPO: COA QUICK STUDY CARDS (101-200)

What is the term for pupillary constriction?

• Mydriasis

• Miosis

• Cycloplegia

• Anisocoria

Answer explanation

Miosis refers to the constriction of the pupils, while mydriasis is the dilation of the pupils. Cycloplegia affects the ability to focus, and anisocoria is a condition of unequal pupil sizes. Therefore, the correct term for pupillary constriction is miosis.

When performing the swinging flashlight test on a patient with a relative afferent pupillary defect (Marcus-Gunn pupil) in the left eye, the expected findings would be:

• Constriction of both pupils with direct light OD and dilation of both pupils when the light "swings" to OS.

• Constriction of both pupils with direct light OD and hippus movement when the light "swings" to OS.

• Constriction of the left pupil in bright light and dilation of both pupils when the light "swings" to OD.

• Initial dilation followed by constriction with direct light OD and total dilation OU when the light "swings" to OS.

Answer explanation

In a Marcus-Gunn pupil, light in the unaffected eye (OD) causes constriction of both pupils. When light swings to the affected eye (OS), both pupils dilate due to the relative afferent defect, confirming the correct choice.

Marcus–Gunn pupil:

• Has a diminished pupil reaction to light

• Is fixed and dilated

• Responds slowly to light

• Shows asymptomatic anisocoria

Answer explanation

The Marcus–Gunn pupil is characterized by a diminished reaction to light, where the affected pupil constricts less than the unaffected one when light is shone in the eye. This makes 'Has a diminished pupil reaction to light' the correct choice.

Shining a bright light into one eye normally causes both pupils to constrict equally. The pupillary reaction in the illuminated eye is called:

• Indirect light reflex

• Consensual light reflex

• Direct light reflex

• Near light reflex

Answer explanation

The pupillary reaction in the illuminated eye is called the direct light reflex, as it refers to the constriction of the pupil in response to light directly entering that eye.

The cones of the human eye are sensitive to which colors?

• Red, green, and blue

• Green, blue, and red

• Blue, yellow, and red

• Red, green, black

Answer explanation

The cones in the human eye are sensitive to three primary colors: red, green, and blue. This trichromatic vision allows us to perceive a wide range of colors by combining these three wavelengths.

How many layers compromise the tear layer?

• 3

• 4

• 5

• 6

Answer explanation

The tear layer consists of three distinct layers: the lipid layer, the aqueous layer, and the mucin layer. Therefore, the correct answer is 3.

What is the abbreviation for “gram”?

• g

• gtt

• gt

• gm

Answer explanation

The abbreviation for 'gram' is 'g'. Other options like 'gtt', 'gt', and 'gm' are not standard abbreviations for gram. Therefore, 'g' is the correct choice.

Titmus testing evaluates stereopsis by assessing if certain portions of the images are:

• Elevated

• Darker

• Clear

• Not visible

Answer explanation

Titmus testing evaluates stereopsis by presenting images where certain portions appear elevated, allowing the assessment of depth perception. The correct answer is 'Elevated' as it directly relates to how stereopsis is tested.

Axial length measurements should be rechecked if there is a difference between the two eyes of more than:

• 0.1 mm

• 0.3 mm

• 1 mm

• 3 mm

Answer explanation

Axial length measurements should be rechecked if there is a difference of more than 0.3 mm between the two eyes, as this threshold helps ensure accurate assessments for conditions like refractive errors.

Schirmer testing is frequently used for a patient who is considering:

• New spectacles

• Cataract surgery

• Contact lenses

• Muscle recession

Answer explanation

Schirmer testing measures tear production, which is crucial for assessing suitability for contact lenses. Patients considering contact lenses often undergo this test to ensure adequate eye moisture.