Practice high-yield Clinical Refraction MCQs from ak Khurana Ophthalmology mcq pdf Cycloplegics, Accommodation & Astigmatism Control (Q161–200). Includes accurate answers and short explanations for exam-ready revision in ophthalmic MCQs 161–200 — Cycloplegia, Accommodation & Astigmatism.
Cycloplegics – Basics & Pharmacology
161. Cycloplegia means:
A. Pupil constriction
B. Paralysis of accommodation
C. Dilation of pupil
D. Relaxation of extraocular muscles
View answer
B. Paralysis of accommodation ✅ Exp: Cycloplegics paralyze the ciliary muscle, suspending accommodation.
162. Cycloplegics act on:
A. Sympathetic system
B. Parasympathetic system
C. Somatic nerves
D. Retinal receptors
View Answer
B. Parasympathetic system ✅ Exp: They block muscarinic receptors (parasympathetic inhibition).
163. Most commonly used cycloplegic in refraction:
A. Tropicamide
B. Cyclopentolate
C. Atropine
D. Homatropine
View Answer
B. Cyclopentolate ✅ Exp: Provides adequate cycloplegia with short duration (4–6 hrs).
164. Most potent cycloplegic drug:
A. Tropicamide
B. Atropine
C. Cyclopentolate
D. Homatropine
View Answer
B. Atropine ✅ Exp: Atropine provides maximum and long-lasting paralysis.
165. Drug of choice for cycloplegia in young children:
A. Atropine
B. Homatropine
C. Tropicamide
D. Cyclopentolate
View Answer
A. Atropine ✅ Exp: Atropine gives full cycloplegia, uncovering latent hypermetropia.
166. Duration of cycloplegia with atropine:
A. 4–6 hr
B. 7–10 days
C. 24 hrs
D. 12 hrs
View Answer
B. 7–10 days ✅ Exp: Effects last up to a week due to strong binding to receptors.
167. Cyclopentolate cycloplegia duration:
A. 6–12 hrs
B. 24 hrs
C. 3 days
D. 7 days
View Answer
A. 6–12 hrs ✅ Exp: Shorter acting, ideal for routine refraction.
168. Tropicamide cycloplegia lasts:
A. 20–30 mins
B. 4 hrs
C. 1 day
D. 1 week
View Answer
A. 20–30 mins ✅ Exp: Weakest cycloplegic; primarily a mydriatic.
169. Atropine cycloplegia is contraindicated in:
A. Infants
B. Elderly
C. Glaucoma patients
D. Myopes
View Answer
C. Glaucoma patients ✅ Exp: May precipitate acute angle-closure glaucoma.
170. Cycloplegic refraction is most useful in:
A. Myopia
B. Hypermetropia
C. Presbyopia
D. Astigmatism only
View Answer
B. Hypermetropia ✅ Exp: Reveals hidden (latent) hypermetropia masked by accommodation.
171. Atropine refraction should be done after:
A. First drop
B. 3 consecutive days
C. Immediately
D. Same day
View Answer
B. 3 consecutive days ✅ Exp: Atropine instilled twice daily for 3 days for full effect.
172. Cyclopentolate is preferred in:
A. Infants
B. School-age children
C. Adults only
D. Presbyopes
View Answer
B. School-age children ✅ Exp: Safer and effective in cooperative older children.
173. Tropicamide suitable for:
A. Adults
B. Infants
C. Toddlers
D. Uncooperative children
View Answer
A. Adults ✅ Exp: Mild action sufficient for adults with minimal latent error.
174. Adverse effect of atropine:
A. Pupil constriction
B. Dryness of mouth
C. Accommodation spasm
D. Miosis
View Answer
B. Dryness of mouth ✅ Exp: Due to systemic anticholinergic action.
176. Cycloplegic refraction is avoided in:
A. Myopia
B. Hypermetropia
C. Anisometropia
D. Astigmatism
View Answer
A. Myopia ✅ Exp: Myopia doesn’t need accommodation paralysis.
Accommodation Physiology
176. Accommodation is mediated by:
A. Lens cortex
B. Ciliary muscle
C. Iris sphincter
D. Retina
View Answer
B. Ciliary muscle ✅ Exp: Ciliary muscle contraction → lens curvature increases.
177. Nerve supply of accommodation:
A. Sympathetic
B. Parasympathetic (3rd nerve)
C. 4th nerve
D. 6th nerve
View Answer
B. Parasympathetic (3rd nerve) ✅ Exp: Fibers originate from Edinger–Westphal nucleus.
178. Mechanism of accommodation described by:
A. Purkinje
B. Helmholtz
C. Donders
D. Sherrington
View Answer
B. Helmholtz ✅ Exp: Helmholtz theory — relaxation of zonules → convex lens.
179. Accommodation increases refractive power by:
A. 0.5 D
B. 1–2 D
C. Up to 12 D
D. None
View Answer
C. Up to 12 D ✅ Exp: Maximum in young eyes; decreases with age (presbyopia).
180 With aging, amplitude of accommodation:
A. Increases
B. Decreases
C. Remains constant
D. Fluctuates
View Answer
B. Decreases ✅ Exp: Lens loses elasticity → presbyopia.
Clinical Measurement of Accommodation ak khurana ophthalmology mcq pdf
181. Near point of accommodation (NPA) is the:
A. Farthest point of clear vision
B. Nearest point of clear vision
C. Average distance
D. Image plane
View Answer
B. Nearest point of clear vision ✅ Exp: The closest point that can be focused clearly.
182. NPA in normal 10-year-old:
A. 10 cm
B. 25 cm
C. 40 cm
D. 60 cm
View Answer
A. 10 cm ✅ Exp: Corresponds to ~10 D amplitude.
183. Amplitude of accommodation (AA) =
A. Reciprocal of near point (m)
B. Log of far point
C. Average distance
D. Linear sum
View Answer
A. Reciprocal of near point (m) ✅ Exp: Measured in diopters (1/NPA in meters).
184. Presbyopia occurs when amplitude falls below:
A. 10 D
B. 5 D
C. 3 D
D. 15 D
View Answer
C. 3 D ✅ Exp: Insufficient to focus at 33 cm (reading distance).
185. The far point of accommodation in emmetropia is:
A. 25 cm
B. Infinity
C. 1 m
D. 2 m
View Answer
B. Infinity ✅ Exp: Distant rays focus on retina without accommodation.
Astigmatism – Types & Principles ak khurana ophthalmology mcq pdf
186. Regular astigmatism means:
A. Different curvature in two meridians
B. Irregular cornea
C. Unequal pupils
D. Diffuse haze
View Answer
A. Different curvature in two meridians ✅ Exp: Two perpendicular principal meridians of different powers.
187. Commonest type of regular astigmatism:
A. Against-the-rule
B. With-the-rule
C. Oblique
D. Irregular
View Answer
B. With-the-rule ✅ Exp: Vertical meridian more curved (common in youth).
188. Against-the-rule astigmatism seen in:
A. Young age
B. Elderly
C. Myopia
D. Infants
View Answer
B. Elderly ✅ Exp: Due to corneal flattening in vertical meridian with age.
189. Simple myopic astigmatism means:
A. One meridian emmetropic, other myopic
B. Both myopic
C. One hypermetropic
D. Mixed
View Answer
A. One meridian emmetropic, other myopic ✅ Exp: Only one focal line before retina.
190. Compound myopic astigmatism means:
A. Both meridians myopic
B. Both hypermetropic
C. One emmetropic
D. Mixed
View Answer
A. Both meridians myopic ✅ Exp: Both foci in front of retina, at different distances.
Astigmatism Measurement & Correction ak khurana ophthalmology mcq pdf
191. Stenopaic slit is used to:
A. Detect astigmatism axis
B. Measure accommodation
C. Test convergence
D. Assess fusion
View Answer
A. Detect astigmatism axis ✅ Exp: Allows isolation of one meridian.
192. Keratometer measures:
A. Corneal curvature
B. Axial length
C. Lens power
D. Retinal magnification
View Answer
A. Corneal curvature ✅ Exp: Gives radius of curvature for astigmatism estimation.
193. Corneal topography provides:
A. Axial length
B. Detailed corneal map
C. Refraction
D. Retinal thickness
View Answer
B. Detailed corneal map ✅ Exp: 3D color-coded map of corneal surface curvature.
195. Lenticular astigmatism arises from:
A. Lens curvature
B. Cornea
C. Retina
D. Vitreous
View Answer
A. Lens curvature ✅ Exp: Due to unequal curvature of crystalline lens surfaces.
196. Total astigmatism =
A. Corneal + Lenticular astigmatism
B. Corneal only
C. Axial error
D. Index myopia
View Answer
A. Corneal + Lenticular astigmatism ✅ Exp: Both components contribute to total error.
196. Astigmatism corrected by:
A. Cylindrical lenses
B. Prisms
C. Spherical lenses
D. Plano lenses
View Answer
A. Cylindrical lenses ✅ Exp: Cylinders have refractive power in one meridian only.
197. Cross cylinder test is used for:
A. Refining axis and power
B. Near addition
C. Fusion
D. Accommodation amplitude
View Answer
A. Refining axis and power ✅ Exp: JCC refines axis and cylinder correction.
198. Mixed astigmatism corrected by:
A. Sphero-cylinder combination
B. Simple cylinder
C. Prisms
D. Spherical only
View Answer
A. Sphero-cylinder combination ✅ Exp: Needs plus in one and minus in the other meridian.
199. Keratoconus produces:
A. Regular astigmatism
B. Irregular astigmatism
C. Hypermetropia
D. Presbyopia
View Answer
B. Irregular astigmatism ✅ Exp: Progressive corneal distortion leads to irregular curvature.
200. Irregular astigmatism corrected best by:
A. Spectacles
B. Rigid contact lenses
C. Cylindrical lenses
D. Bifocals
View Answer
B. Rigid contact lenses ✅ Exp: Rigid lenses create a uniform refracting surface.
