Fortnightly Quiz 6

What is the definition of blindness as per World Health Organization (WHO) standards?

• A Vision 20/200 or worse.
• B Vision 20/400 or worse.
• C Vision worse than 20/400.
• D Vision worse than counting fingers (CF) at 3 feet.

When taking a visual acuity test to determine legal blindness, the following conditions must be considered.

• A Room illumination
• B Patient co-operation
• C Letter contrast on the acuity chart
• D All of the above

Which of the following types of ophthalmic disease is/are the most common cause of pediatric blindness in the world?

• A Congenital glaucoma.
• B Cataracts.
• C Corneal scarring and retinal diseases.
• D Disorders of the entire globe.

Which of the following statement is false?

• A Meter system (M system) was first advocated by Sloan
• B 1M optotype will subtend 1 min of arc at 1m.
• C 1M is equivalent to 20/50 at 40 cm
• D Lighthouse near acuity test is recorded in metric system.

Refractive error in Down syndrome is predominantly

• A Low hypermetropia
• B Moderate to high hypermetropia
• C Irregular astigmatism
• D Moderate to high myopia

In low vision evaluation trial frame is used rather than phoropter. Which of the following statement is false in this context?

• A large lens aperture enables the patient to assume habitual eccentric fixation.
• B Easy observation of patient head and eye turn
• C Difficult to compare trial lenses
• D High powered doublet microscope can be incorporated into prescription.

An 8 year old white boy was initially diagnosed as having albinism with associated nystagmus and congenital myopia. His parents reported that his vision had been stable since birth. His best corrected visual acuity was 10/60 in each eye. Amsler grid and tangential screen testing revealed no field defects. External eye examination was normal. There was no iris transillumination with slit lamp examination. Ophthalmoscope revealed clear media, normal macula and foveal reflex in both eyes. There was a relative loss of RPE pigmentation around the disc in each eye. Which battery of test will you like to use for determining the cause of his visual loss.

• A EOG, Ishihara plates and Nagel anomaloscope
• B ERG, VEP, D15 test.
• C ERG, D15, Nagel Anomaloscope
• D All the following combination.

A patient has a best corrected near acuity of 0.33/4M and desires to read the newspaper which is found to be 1M print. What reading cap power would be required for 2.2x telescope to accomplish this task

• A Plus 4.04D
• B Plus 4.44D
• C Plus 5.51D
• D Plus 5.54D

An aphakic patient wears +10.00 D glasses at a vertex distance of 10 mm. What power of contact lens should be ordered to fit on K's?

• A Plus 9D
• B Plus 10D
• C Plus 11D
• D Plus 9.5D

A patient has K's of 42.00 D at 90°/40.00 D at 180° and refraction of - 1.50 + 0.50 × 90°. A plano hard contact lens is fit on the flatter K. What over-refraction is measured?

• A -1.00 + 1.50 × 180°
• B 1.50 - 0.50 × 90°
• C -0.50 + 0.50 × 180°
• D 0.50 + 1.50 × 90°

Which change would allow a hard contact lens to fit more tightly to a cornea?

• A Decreasing the diameter from 8.80 mm to 8.40 mm
• B Decreasing the base curve from 8.20 mm to 8.00 mm
• C Increasing the optical zone from 8.20 mm to 8.40 mm
• D Increasing the power from -3.00 D to -3.50 D

Which one of the following single changes results in the selection of a lens more powerful than intended?

• A Using an A-constant of 116.8 instead of 117.3
• B Axial length measured as 20.5 mm rather than 20.2 mm
• C Average keratometry of 44.50 D in place of 44.00 D
• D Placing the lens in the anterior chamber instead of in the capsular bag

A patient purchased a pair of sunglasses with a dark blue tint. Which of these colors would be the hardest to see?

• A Red
• B Blue
• C Green
• D Purple

A patient who had bilateral LASIK is complaining of haloes and starbursts while driving at night. Which of the following measures could improve his symptoms?

• A Wear polarized glasses
• B Constrict pupil
• C Turn on the interior reading light in car
• D Treat with a larger ablation zone

A patient has a red Maddox rod with the cylinders oriented horizontally placed over her left eye. What does she see when she views a distant white fixation light?

• A Red light, horizontal white line
• B Red light, vertical white line
• C White light, horizontal red line
• D White light, vertical red line

Which of the following statement regarding the electromagnetic radiation is correct

• A Velocity of all electromagnetic radiation is same
• B Wavelength of blue light is longer than that of red light
• C UV A radiation reaches the retina of phakic eyes.
• D IR A radiation is absorbed by the crystalline lens

Which of the following statement regarding the pinhole is correct

• A Pinhole increases the depth of focus but decreases the depth of field
• B Standard British pinhole size is 1.35 mm
• C Pinhole decreases the size of blur circle on retina
• D By reducing the size of pinhole , effects of diffraction are minimized

Which of the following statement regarding clinical uses of reflection is correct

• A The first purkinje image is real and inverted
• B The first purkinje image may be used to assess squint
• C Keratoscopy utilizes the second purkinje image
• D The third and fourth purkinje images have no application in ophthalmology.

A 2x magnifying lens is positioned 10 cm from book. If the reference near point is 25 cm which statement is correct

• A Accommodative effort is induced in the emmetropic reader
• B Image is inverted
• C Power of lens measured with lensometer is +2D.
• D Observer’s depth of focus is increased.

A patient has confirmed bitemporal hemianopia, the direction of the base of prismin a spectacle lens should be

• A Nasal
• B Inferior
• C Superior
• D Temporal