Explore 40 high-yield Clinical Subjective Refraction MCQs (Q81–120) with answers and short explanations covering Subjective Refraction Techniques, Duochrome Test, Fogging, Binocular Balance, and Jackson Cross Cylinder (JCC). Perfect for optometry and ophthalmology exam preparation — understand key concepts like “most plus for best vision,” astigmatic correction, and final prescription principles. Visit Our Ophthalmology mcq page to find topic wise MCQs.
Fundamentals of Subjective Refraction
81. Subjective refraction is:
A. Objective method
B. Based on patient responses
C. Autorefraction
D. Retinoscopy
View Answer
B. Based on patient responses ✅ Exp: The patient judges clarity using trial lenses.
82. Subjective refraction is usually done:
A. Before retinoscopy
B. After retinoscopy
C. Instead of retinoscopy
D. After cycloplegia only
View Answer
B. After retinoscopy ✅ Exp: Objective refraction gives starting point; subjective refines it.
82. Essential requirement for subjective refraction:
A. Full dilation
B. Active accommodation control
C. Dark room
D. Red filter
View Answer
B. Active accommodation control ✅ Exp: Accommodation must be relaxed to avoid false minus answers.
85. The fogging technique is used to:
A. Stimulate accommodation
B. Relax accommodation
C. Measure vergence
D. Check stereo-acuity
View Answer
B. Relax accommodation ✅ Exp: Plus lenses blur retinal image and relax the ciliary muscle.
86. When fogging, you start with:
A. Minus lens
B. Plus lens
C. Cylinder
D. Plano lens
View Answer
B. Plus lens ✅ Exp: Begin with + lenses then reduce until best clarity.
86 The endpoint of fogging is:
A. First clear vision
B. Brightest letters
C. Full blur
D. Binocular fusion
View Answer
A. First clear vision ✅ Exp: Stop when letters just become sharp → no over-minusing.
87. The Duochrome (red-green) test is based on:
A. Chromatic aberration
B. Spherical aberration
C. Diffraction
D. Astigmatism
View Answer
A. Chromatic aberration ✅ Exp: Green (-) focuses in front of red (+).
88. In Duochrome test, if letters on green are clearer:
A. Add plus lens
B. Add minus lens
C. No change
D. Cycloplege
View Answer
A. Add plus lens ✅ Exp: Green side = over-minused; need + lens to shift focus back.
89. If letters on red are clearer:
A. Add minus lens
B. Add plus
C. Leave as is
D. Refog
View Answer
A. Add minus lens ✅ Exp: Red focuses behind retina → need – lens to move forward.
90. The Duochrome test should be done:
A. Under fog
B. At final endpoint
C. Before subjective refraction
D. With one eye closed
View Answer
B. At final endpoint ✅ Exp: Used to fine-tune final sphere power.
Binocular Balance & Monocular Refraction
91. Binocular balance aims to:
A. Equalize accommodation in both eyes
B. Equalize acuity
C. Relax vergence
D. Induce phoria
View Answer
A. Equalize accommodation in both eyes ✅ Exp: Ensures symmetrical accommodation after monocular testing.
92. Fogging both eyes equally is used for:
A. Phoria test
B. Binocular balance
C. Cross-cylinder
D. Red-green test
View Answer
B. Binocular balance ✅ Exp: Slight blur relaxes both eyes for comparison.
93. Dissociation methods in binocular balance include:
A. Polaroid filters
B. Red-green only
C. Neutral density filters
D. Maddox wing alone
View Answer
A. Polaroid filters ✅ Exp: Different images shown to each eye for comparison.
94. In binocular balance, if right eye reads clearer:
A. Add plus to right
B. Add plus to left
C. Minus to right
D. Minus to left
View Answer
B. Add plus to left ✅ Exp: Add + to the clearer eye to balance accommodation.
95. Binocular refraction is performed to:
A. Measure muscle balance
B. Ensure fusion with both eyes
C. Relax accommodation
D. Induce monocular vision
View Answer
B. Ensure fusion with both eyes ✅ Exp: Confirms clarity under normal binocular conditions.
Jackson Cross Cylinder (JCC) Technique
96. JCC test is used to refine:
A. Spherical correction
B. Astigmatic axis and power
C. Accommodation
D. Fusion
View Answer
B. Astigmatic axis and power ✅ Exp: Compares two equal opposite cylinder powers.
96 JCC lens contains:
A. One cylinder
B. Two cylinders of equal power, opposite sign
C. Spherical lens
D. Prism
View Answer
B. Two cylinders of equal power, opposite sign ✅ Exp: ±0.25 or ±0.50 D cylinders mounted crossed 90°.
98. JCC is placed with:
A. Axis parallel to test cylinder
B. Axis perpendicular to test
C. Randomly
D. Horizontal only
View Answer
A. Axis parallel to test cylinder ✅ Exp: Used to flip and compare axes for clarity.
99. Axis refinement is done first when:
A. Astigmatism < 1 D
B. Astigmatism > 0.75 D
C. Always power first
D. Never needed
View Answer
B. Astigmatism > 0.75 D ✅ Exp: Correct axis is essential before adjusting power.
100 After axis is finalized, JCC is used to refine:
A. Sphere
B. Cylinder power
C. Prism
D. Accommodation
View Answer
B. Cylinder power ✅ Exp: Determines final astigmatic power for best vision.
Sphere Power Refinement
101. After cylinder correction, sphere is checked by:
A. Duochrome test
B. Cross cylinder
C. Fogging again
D. Phoria test
View Answer
A. Duochrome test Exp: Red-green test balances chromatic focus for final sphere.
103. The endpoint of sphere refinement is:
A. Clearest letters on red-green balanced
B. Minimum plus maximum acuity
C. Maximum minus maximum acuity
D. Equal brightness
View Answer
A. Clearest letters on red-green balanced ✅ Exp: Aim for least minus or most plus with best acuity.
103. “Most plus for best vision” principle prevents:
A. Over-minus correction
B. Under-plus correction
C. Accommodation stimulation
D. Fogging
View Answer
A. Over-minus correction ✅ Exp: Avoids accommodative strain and myopic shift.
104. During subjective refraction, accommodation is controlled by:
A. Fogging
B. Prisms
C. Occluder
D. Stenopaic slit
View Answer
A. Fogging ✅ Exp: Fogging keeps the ciliary muscle relaxed.
105. End-point criterion for hypermetropes:
A. Most minus
B. Most plus for best vision
C. Balanced lens
D. Clear on red
View Answer
B. Most plus for best vision ✅ Exp: To ensure adequate relaxation of accommodation.
Astigmatic Correction Practice
106. Spherocylindrical correction notation follows:
A. + cylinder form
B. – cylinder only
C. Mixed
D. Prismatic
View Answer
A. + cylinder form ✅ Exp: Standard in ophthalmology prescriptions.
107. Conversion from + to – cylinder form changes axis by:
A. 45°
B. 90°
C. 180°
D. No change
View Answer
B. 90° ✅ Exp: Axis shift = 90° when sign of cylinder reversed.
108. Transposition of +2 DS / –1 DC × 180 equals:
A. +1 DS / +1 DC × 90
B. +3 DS / +1 DC × 180
C. –2 DS / +1 DC × 90
D. –1 DS / –1 DC × 90
View Answer
A. +1 DS / +1 DC × 90 ✅ Exp: Add sphere and cylinder, change sign, shift axis 90°.
109. Astigmatic error should be checked under:
A. Cycloplegia
B. Dilated pupil
C. Fog only
D. No illumination
View Answer
A. Cycloplegia ✅ Exp: To eliminate accommodation influence.
110. Cross cylinder axis verification is important in:
A. Mixed astigmatism
B. Simple myopia
C. Hypermetropia
D. Presbyopia
View Answer
A. Mixed astigmatism ✅ Exp: Axis determines correct orientation of power.
Advanced Refraction Techniques
111. Stenopaic slit test helps in:
A. Determining astigmatic axis
B. Measuring accommodation
C. Testing depth of focus
D. Color vision
View Answer
A. Determining astigmatic axis ✅ Exp: Allows testing one meridian at a time.
112. When two axes give same clarity, choose:
A. Axis closer to horizontal
B. Axis closer to vertical
C. Midpoint
D. Average of both
View Answer
B. Axis closer to vertical ✅ Exp: Habitual astigmatism is usually with-the-rule (vertical steeper).
113. Cylinder power is recorded to nearest:
A. 0.12 D
B. 0.25 D
C. 0.50 D
D. 1.00 D
View Answer
B. 0.25 D ✅ Exp: Trial lenses commonly in 0.25 D steps.
114. Fogging is not recommended in:
A. High myopia
B. Hypermetropia
C. Children
D. Cycloplegia
View Answer
A. High myopia ✅ Exp: Already no accommodation → may worsen blur.
115. Red-green test not reliable in:
A. Color vision defects
B. Amblyopia
C. Hypermetropia
D. Presbyopia
View Answer
A. Color vision defects ✅ Exp: Color-blind patients can’t compare contrast.
116. Subjective refraction is difficult in:
A. Children
B. Young adults
C. Presbyopes
D. Hyperopes
View Answer
A. Children ✅ Exp: Cooperation and response are poor in kids.
117. Trial frame should be set so optical centers align with:
A. Canthus
B. Pupillary center
C. Corneal margin
D. Medial limbus
View Answer
B. Pupillary center ✅ Exp: Prevents induced prismatic effects.
118. Vertex distance is important for lens power > ±4 D because:
A. Magnification changes
B. Color shift
C. Axis rotation
D. Accommodation
View Answer
A. Magnification changes ✅ Exp: Effective power varies with lens distance from eye.
119. Cycloplegic refraction should always be confirmed by:
A. Retinoscopy
B. Subjective refraction
C. Autorefraction only
D. Keratomety
View Answer
B. Subjective refraction ✅ Exp: To ensure best correction after relaxation.
120. The final prescription is based on:
A. Objective findings only
B. Patient’s subjective acceptance
C. Trial lenses alone
D. Doctor’s judgment only
View Answer
B. Patient’s subjective acceptance ✅ Exp: Final glasses depend on patient’s comfort and clarity.
