HCTM Intensive Course 2023

What is the working distance lens diopter required if the retinoscopy is performed at 67cm?

• +1.00DS

• +1.50DS

• +2.00DS

• +2.50DS

If both reflexes at 90 & 180 degrees meridians show "with" movement during retinoscopy, you should:

• neutralize less with reflex first

• neutralize the brighter reflex first

• neutralize the dimmer reflex as first

• neutralize with negative lens first

Choose the TRUE statement about duochrome test.

• It is based on the principle of spherical aberration.

• It can be used on patient with VA 6/24.

• Give plus will shift the wavelength to the front.

• If the focus is behind the retina, the targets on the red side will appear clearer.

-2.50DS is needed to neutralize the reflex during retinoscopy without working distance lens at 67cm. What is the final prescription?

• -0.50DS

• -1.00DS

• -4.00DS

• -4.50DS

Choose the TRUE statement about subjective refraction.

• The longer the interval of Sturm, the smaller the circle of least confusion.

• We should refine power before the axis in JCC technique.

• Binocular balancing is to balance the spherical power between both eyes.

• BVS checking should be performed before and after JCC technique.

Choose the TRUE statement.

•  With a plus lens, Ray 3 travels parallel to the optical axis and after refraction passes through the lens’s secondary focal point.

• Total internal reflection occurs when the angle of incidence exceeds critical angle.

• Lens thickness needs to be taken into account to calculate a thin optical lens’s power.

• Reflection can be quantified using Snell’s law.

Choose the TRUE statement about prisms.

• The image is displaced towards the base of the prism.

• Prismatic effect only occurs when a prism is mounted on the optical lens.

• Prismatic power can be calculated using Prentice’s rule (P=cF).

• Prism is always prescribed with the base at the bottom.

The readings from a focimeter as below:

Reading A: -0.50 x 90

Reading B: -1.00 x 180

What is the power in sphere-minus cylinder form?

• -0.50/-0.50 x 180

• -0.50/-1.50 x 90

• -1.50/-1.50 x 180

• -1.00/-0.50 x 90

Choose the TRUE statement about keratometry.

• One position variable doubling keratometer measures one principal meridian at one time.

• Javal-Schiotz keratometer require a second adjustment to measure the second principal meridian.

• With Bausch & Lomb keratometer, the 3 mires must be adjusted until a single mire is achieved for corneal curvature measurement.

• Bausch & Lomb keratometer is based on image doubling method but not Javal-Schiotz.

Choose the TRUE statement.

• Galilean telescope can be used for distance only.

• Galilean telescope consists of one convex lens and one concave lens.

• Galilean telescope provides a wide field of view.

• The image produced by Galilean telescope is virtual and erect.