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NZ Optometry Registration practice questions

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Question 1Ocular Anatomy, Physiology and Pathology

Which structure produces the aqueous humour that fills the anterior chamber?

  1. The corneal endothelium
  2. The pigmented epithelium of the iris
  3. The trabecular meshwork
  4. The ciliary epithelium covering the ciliary processes Correct answer.

Explanation

Aqueous humour is actively secreted by the non-pigmented ciliary epithelium overlying the ciliary processes, using carbonic anhydrase and Na+/K+-ATPase transport. The iris and corneal endothelium do not secrete aqueous, and the trabecular meshwork is the main outflow route rather than a source.

Question 2Ocular Anatomy, Physiology and Pathology

Rods are more sensitive than cones to dim light mainly because rods have which property?

  1. Three distinct photopigment types
  2. Slower response and greater spatial summation Correct answer.
  3. Faster photopigment regeneration
  4. A higher density in the foveola

Explanation

Rods converge heavily onto bipolar and ganglion cells, giving large receptive fields and temporal summation that amplify dim signals. They also contain only rhodopsin, which is more sensitive to low light than cone opsins. Cones have faster kinetics and higher acuity but lower scotopic sensitivity.

Question 3Ocular Anatomy, Physiology and Pathology

A patient reports sudden painless loss of vision in one eye with a pale, swollen retina and a cherry-red spot at the macula. Which diagnosis fits best?

  1. Central retinal vein occlusion
  2. Vitreous haemorrhage
  3. Optic neuritis
  4. Central retinal artery occlusion Correct answer.

Explanation

Central retinal artery occlusion produces sudden painless visual loss with retinal pallor from ischaemia and a cherry-red spot where the thin fovea overlies the intact choroidal circulation. The retinal arteries appear attenuated and the picture is unilateral and acute.

Question 4Ocular Anatomy, Physiology and Pathology

Which corneal layer is chiefly responsible for maintaining corneal deturgescence?

  1. Stroma
  2. Epithelium
  3. Bowman layer
  4. Endothelium Correct answer.

Explanation

The corneal endothelium is a monolayer of pump cells that actively transports fluid out of the stroma via Na+/K+-ATPase, keeping the stroma relatively dehydrated and clear. Stromal glycosaminoglycans would otherwise draw in water and cause oedema.

Question 5Ocular Anatomy, Physiology and Pathology

Which cranial nerve supplies the levator palpebrae superioris?

  1. Trochlear nerve (IV)
  2. Abducens nerve (VI)
  3. Oculomotor nerve (III) Correct answer.
  4. Facial nerve (VII)

Explanation

The levator palpebrae superioris is innervated by the superior division of the oculomotor nerve (CN III). This is why a complete third nerve palsy produces ptosis alongside the motility deficit.

Question 6Ocular Anatomy, Physiology and Pathology

A patient with long-standing poorly controlled diabetes presents with a dense vitreous haemorrhage. Which mechanism most likely explains this?

  1. Choroidal neovascular membrane
  2. Retinal detachment from a retinal tear
  3. Central retinal artery occlusion
  4. Proliferative diabetic retinopathy with fragile new vessels Correct answer.

Explanation

Prolonged hyperglycaemia causes retinal ischaemia and upregulation of VEGF, driving neovascularisation at the disc and elsewhere. These new vessels are fragile and bleed into the vitreous, causing sudden visual loss.

Question 7Ocular Anatomy, Physiology and Pathology

Tear film stability is chiefly assessed by which clinical test?

  1. Tear break-up time Correct answer.
  2. Schirmer test
  3. Tear osmolarity
  4. Rose bengal staining

Explanation

Tear break-up time measures the interval between a complete blink and the first dry spot on the cornea, directly reflecting tear film stability. A short break-up time indicates an unstable lipid or mucin layer.

Question 8Ocular Anatomy, Physiology and Pathology

Which retinal layer contains the photoreceptor cell bodies?

  1. Inner nuclear layer
  2. Outer nuclear layer Correct answer.
  3. Ganglion cell layer
  4. Outer plexiform layer

Explanation

The outer nuclear layer contains the nuclei of rod and cone photoreceptors, whose inner and outer segments extend towards the retinal pigment epithelium. Synapses with bipolar cells occur in the outer plexiform layer, not the nuclear layer.

Question 9Ocular Anatomy, Physiology and Pathology

A 30-year-old presents with an acute red eye, photophobia, and a dendritic corneal lesion after contact lens use. Which organism is most likely?

  1. Herpes simplex virus Correct answer.
  2. Staphylococcus aureus
  3. Pseudomonas aeruginosa
  4. Acanthamoeba

Explanation

A branching dendritic epithelial lesion with photophobia and a red eye is the classic presentation of herpes simplex keratitis. Fluorescein staining shows the dendritic pattern, which distinguishes it from bacterial or amoebic ulcers.

Question 10Ocular Anatomy, Physiology and Pathology

In a normal accommodation response, which change occurs?

  1. The pupil dilates and the lens flattens
  2. The lens becomes flatter and the ciliary muscle relaxes
  3. The lens becomes more convex and the ciliary muscle contracts Correct answer.
  4. The zonules tighten and the lens becomes more convex

Explanation

Accommodation is driven by parasympathetic contraction of the ciliary muscle, which moves the ciliary body inward and relaxes the zonules. The elastic lens then rounds up, becoming more convex and increasing its refractive power for near vision.

Question 11Ocular Anatomy, Physiology and Pathology

A patient with bilateral temporal field loss and bitemporal hemianopia is most likely to have a lesion at which site?

  1. Lateral geniculate nucleus
  2. Optic tract
  3. Optic chiasm Correct answer.
  4. Optic radiation

Explanation

Fibres from the nasal retina of each eye decussate at the optic chiasm and carry the temporal visual field. A chiasmal lesion, classically a pituitary adenoma, therefore produces bitemporal hemianopia.

Question 12Ocular Anatomy, Physiology and Pathology

Which feature best distinguishes a hordeolum from a chalazion?

  1. Hordeolum is a painless lipogranuloma of the meibomian gland
  2. Chalazion presents with marked acute pain
  3. Chalazion is an acute bacterial infection of the lash follicle
  4. Hordeolum is an acute tender infection of the lid margin glands Correct answer.

Explanation

A hordeolum is an acute, tender infection of a lash follicle (external) or meibomian gland (internal), typically staphylococcal. A chalazion is a chronic, usually painless lipogranulomatous inflammation of a meibomian gland.

Question 13Ocular Anatomy, Physiology and Pathology

Which mechanism explains the elevated intraocular pressure in primary open-angle glaucoma?

  1. Overproduction of aqueous humour by the ciliary body
  2. Blockage of aqueous flow at the pupil
  3. Closure of the anterior chamber angle by the iris
  4. Increased resistance to aqueous outflow at the trabecular meshwork Correct answer.

Explanation

Primary open-angle glaucoma results from increased resistance to aqueous outflow through the trabecular meshwork and Schlemm canal despite an open angle. Aqueous production is typically normal, and the angle remains open on gonioscopy.

Question 14Ocular Anatomy, Physiology and Pathology

Which retinal cells provide lateral inhibition that sharpens contrast at the edges of a stimulus?

  1. Horizontal cells Correct answer.
  2. Müller cells
  3. Retinal ganglion cells
  4. Amacrine cells

Explanation

Horizontal cells in the outer retina receive input from photoreceptors and feed back laterally onto neighbouring photoreceptors, generating centre-surround antagonism. This lateral inhibition enhances edge contrast in the ganglion cell response.

Question 15Ocular Anatomy, Physiology and Pathology

A patient develops a sudden painless curtain over the superior visual field with flashes and floaters. Which process is most likely?

  1. Central serous chorioretinopathy
  2. Vitreous haemorrhage
  3. Optic neuritis
  4. Posterior vitreous detachment with a retinal tear Correct answer.

Explanation

Acute posterior vitreous detachment can cause photopsia and floaters, and if it tears the retina, subretinal fluid produces a field defect described as a curtain. The superior field loss suggests inferior retinal detachment.

Question 16Ocular Anatomy, Physiology and Pathology

Which corneal dystrophy is associated with a defect in the TGFBI gene and produces recurrent corneal erosions with map-dot-fingerprint changes?

  1. Lattice dystrophy
  2. Epithelial basement membrane dystrophy Correct answer.
  3. Keratoconus
  4. Fuchs endothelial dystrophy

Explanation

Epithelial basement membrane dystrophy produces map-dot-fingerprint epithelial changes and recurrent erosions, though it is not classically a TGFBI dystrophy. Lattice and granular dystrophies are the classic TGFBI (BIGH3) dystrophies, so the stem's combination requires care. The best answer among those listed that produces map-dot-fingerprint changes is epithelial basement membrane dystrophy.

Question 17Ocular Anatomy, Physiology and Pathology

Which pupil finding is most consistent with a left optic nerve lesion?

  1. Left pupil dilates more briskly to light than the right
  2. A left efferent pupillary defect with ptosis
  3. A left relative afferent pupillary defect Correct answer.
  4. Bilateral fixed dilated pupils

Explanation

An optic nerve lesion reduces the afferent light signal from that eye, producing a relative afferent pupillary defect on the swinging flashlight test. The efferent pathway and iris sphincter remain intact, so the pupil still constricts to direct light, just less vigorously.

Question 18Ocular Anatomy, Physiology and Pathology

A patient on long-term topical corticosteroid develops raised intraocular pressure. Which mechanism best explains this?

  1. Increased episcleral venous pressure
  2. Angle closure from iris bombe
  3. Increased aqueous production by the ciliary body
  4. Reduced outflow facility at the trabecular meshwork Correct answer.

Explanation

Steroid-induced ocular hypertension results from reduced trabecular meshwork outflow facility, likely through changes in extracellular matrix and cytoskeleton. Aqueous production is not increased, and the angle remains open.

Question 19Ocular Anatomy, Physiology and Pathology

Which structure forms the major attachment site of the crystalline lens to the ciliary body?

  1. The zonular fibres arising from the pars plana
  2. The zonular fibres arising from the pars plicata Correct answer.
  3. The anterior hyaloid membrane
  4. The iris root

Explanation

The lens is suspended by zonular fibres that arise mainly from the pars plicata of the ciliary body and insert on the lens capsule. These fibres transmit ciliary muscle contraction to the lens during accommodation.

Question 20Ocular Anatomy, Physiology and Pathology

A patient with Marfan syndrome is at increased risk of which lens abnormality?

  1. Posterior subcapsular cataract
  2. Spherophakia
  3. Ectopia lentis Correct answer.
  4. Anterior lenticonus

Explanation

Marfan syndrome involves fibrillin-1 deficiency, weakening the zonules and causing ectopia lentis, usually superotemporal displacement. This lens subluxation can produce refractive changes and monocular diplopia.

Question 21Ocular Anatomy, Physiology and Pathology

Which feature of the optic disc is most characteristic of glaucomatous damage?

  1. A small cup-to-disc ratio
  2. Swelling of the disc margin
  3. Peripapillary haemorrhage only
  4. Progressive thinning of the neuroretinal rim Correct answer.

Explanation

Glaucomatous optic neuropathy causes progressive loss of retinal ganglion cell axons, seen as neuroretinal rim thinning and cupping. The cup enlarges relative to the disc, and rim tissue, especially inferiorly and superiorly, is lost.

Question 22Ocular Anatomy, Physiology and Pathology

Which of the following best describes the foveal avascular zone?

  1. A region supplied only by retinal arteries
  2. An area of the peripheral retina with sparse capillaries
  3. A region of the macula supplied only by the choroid Correct answer.
  4. A zone where the retinal pigment epithelium is absent

Explanation

The fovea lies within the macula and is free of retinal capillaries, receiving oxygen and nutrients by diffusion from the choroid. This avascular zone preserves the optical clarity needed for high-acuity central vision.

Question 23Ocular Anatomy, Physiology and Pathology

A patient presents with a painful red eye, decreased vision, and a hypopyon after cataract surgery. What is the most appropriate immediate concern?

  1. Uveitis from sarcoidosis
  2. Sympathetic ophthalmia
  3. Retained lens fragment
  4. Endophthalmitis Correct answer.

Explanation

A hypopyon with pain and visual loss after intraocular surgery is a red flag for acute endophthalmitis, usually from coagulase-negative staphylococci. It is an ophthalmic emergency requiring urgent vitreous sampling and intravitreal antibiotics.

Question 24Ocular Anatomy, Physiology and Pathology

In the phototransduction cascade, what is the direct effect of activated rhodopsin on transducin?

  1. It closes cGMP-gated channels directly
  2. It phosphorylates arrestin
  3. It catalyses GDP/GTP exchange on the alpha subunit Correct answer.
  4. It hydrolyses cGMP to GMP

Explanation

Light-activated rhodopsin acts as a guanine nucleotide exchange factor, promoting GTP binding to the alpha subunit of transducin. The GTP-bound alpha subunit then activates phosphodiesterase, which hydrolyses cGMP and closes the channels.

Question 25Ocular Anatomy, Physiology and Pathology

Which statement about the blood-retinal barrier is correct?

  1. It is maintained mainly by Müller cell gap junctions
  2. It comprises tight junctions of retinal capillary endothelium and the RPE Correct answer.
  3. It is formed only by the retinal pigment epithelium
  4. It is absent in the fovea

Explanation

The inner blood-retinal barrier is formed by non-fenestrated retinal capillary endothelial cells joined by tight junctions, while the outer barrier is the RPE. Together they regulate the retinal microenvironment and exclude macromolecules.

Question 26Ocular Anatomy, Physiology and Pathology

A 65-year-old man reports a sudden painless loss of vision in the right eye. Fundoscopy reveals a pale, oedematous retina with a cherry-red spot at the macula. Which retinal artery is most likely occluded?

  1. Cilioretinal artery
  2. Central retinal artery Correct answer.
  3. Posterior ciliary artery
  4. Central retinal vein

Explanation

Central retinal artery occlusion classically produces a sudden painless loss of vision with a pale, oedematous retina and a cherry-red spot at the macula, because the fovea is spared by the choroidal circulation. The cherry-red spot is the normal choroidal glow seen through the thin fovea, contrasting with the surrounding ischaemic retina.

Question 27Ocular Anatomy, Physiology and Pathology

During a routine eye examination, a 70-year-old patient is found to have fine, basophilic, dot-like deposits on the anterior lens capsule near the pupillary margin. These are most consistent with which age-related change?

  1. Nuclear sclerosis
  2. Posterior subcapsular cataract
  3. Pseudoexfoliation of the lens capsule Correct answer.
  4. Cortical cataract

Explanation

Pseudoexfoliation syndrome is characterised by the deposition of fine, basophilic, fibrillar material on the anterior lens capsule, often most prominent near the pupillary margin. This material is produced by the lens epithelium and is a common age-related finding that can be associated with glaucoma and complications during cataract surgery.

Question 28Ocular Anatomy, Physiology and Pathology

A 45-year-old woman presents with a gradual onset of double vision, worse on right gaze, and a right-sided ptosis. She is found to have a small pupil on the right in dim light compared to the left. Which structure is most likely affected?

  1. Right oculomotor nerve (CN III) Correct answer.
  2. Right abducens nerve (CN VI)
  3. Right trochlear nerve (CN IV)
  4. Right sympathetic pathway

Explanation

A right oculomotor nerve palsy causes ptosis, a dilated pupil (mydriasis) due to loss of parasympathetic innervation, and diplopia that is worse on right gaze because of weakness of the medial rectus, superior rectus, inferior rectus, and inferior oblique. The combination of ptosis and a dilated pupil points to CN III involvement.

Question 29Ocular Anatomy, Physiology and Pathology

A 55-year-old man with a history of recurrent uveitis presents with a sudden onset of floaters and decreased vision. Fundoscopy shows a hazy view of the retina with cells in the vitreous and a focal area of retinal necrosis. Which of the following is the most likely diagnosis?

  1. Primary intraocular lymphoma
  2. Cytomegalovirus retinitis
  3. Acute retinal necrosis Correct answer.
  4. Toxoplasmic retinochoroiditis

Explanation

Acute retinal necrosis (ARN) typically presents with a sudden onset of floaters and decreased vision, vitritis, and focal areas of retinal necrosis, often in a patient with a history of recurrent uveitis. It is most commonly caused by herpes simplex virus or varicella-zoster virus and can progress rapidly, requiring prompt antiviral treatment.

Question 30Ocular Anatomy, Physiology and Pathology

A 60-year-old patient with type 2 diabetes and poorly controlled hypertension presents with a sudden painless loss of vision in the left eye. Fundoscopy shows a swollen optic disc with splinter haemorrhages at the disc margin and a pale, oedematous retina. Which vascular event is most likely responsible?

  1. Vitreous haemorrhage
  2. Anterior ischaemic optic neuropathy
  3. Branch retinal artery occlusion
  4. Central retinal vein occlusion Correct answer.

Explanation

Central retinal vein occlusion typically presents with a sudden painless loss of vision and a ‘blood-and-thunder’ fundus, with disc swelling, venous engorgement, and widespread retinal haemorrhages. The presence of a swollen optic disc with splinter haemorrhages and retinal oedema is characteristic of the impaired venous drainage.

Question 31Refraction, Binocular Vision and Accommodation

A 24-year-old patient has an uncorrected visual acuity of 6/6 at distance and reports clear near vision. Retinoscopy in the distance condition reveals a neutral reflex at 50 cm with the working distance lens removed. What is the most likely refractive status?

  1. Low myopia of about -0.50 D
  2. Low hyperopia of about +0.50 D
  3. Astigmatism of 1.00 D
  4. Emmetropia Correct answer.

Explanation

A neutral reflex at 50 cm corresponds to a working distance of 2.00 D, which is subtracted, leaving plano. With unaided 6/6 distance acuity and comfortable near vision, the refraction is emmetropic.

Question 32Refraction, Binocular Vision and Accommodation

Which statement best describes the purpose of the duochrome (red-green) test during subjective refraction?

  1. It detects colour vision deficiency before refraction
  2. It measures the amplitude of accommodation objectively
  3. It assesses the phoria at near under dissociated conditions
  4. It confirms the spherical endpoint by comparing clarity of red and green targets Correct answer.

Explanation

The duochrome test exploits longitudinal chromatic aberration: green focuses in front of red. When the circle of least confusion is at the retina, the red and green targets appear equally clear, which helps refine the spherical endpoint, usually favouring the green in slight over-minus.

Question 33Refraction, Binocular Vision and Accommodation

During a cover test, a patient's uncovered eye moves inward (toward the nose) to take up fixation when the other eye is covered. What does this indicate?

  1. Exotropia
  2. Exophoria
  3. Esotropia Correct answer.
  4. Hypertropia

Explanation

In the cover test, the uncovered eye moves to take up fixation when the fellow eye is covered. An inward (nasal) movement of the uncovered eye indicates an esotropia, meaning the eye was deviated outward before the cover.

Question 34Refraction, Binocular Vision and Accommodation

Which of the following best defines the near point of accommodation?

  1. The point where the two visual axes intersect during convergence
  2. The point conjugate to the retina when the eye is fully relaxed
  3. The farthest point at which an object can be seen clearly without accommodation
  4. The closest point at which an object can be seen clearly with maximum accommodation Correct answer.

Explanation

The near point of accommodation is the nearest point that can be brought to a clear focus on the retina when the eye exerts its maximum accommodative effort. Its distance from the eye gives the amplitude of accommodation in dioptres.

Question 35Refraction, Binocular Vision and Accommodation

A patient's amplitude of accommodation is measured as 8.00 D. What is the approximate near point of accommodation?

  1. 125 cm
  2. 12.5 cm Correct answer.
  3. 8 cm
  4. 80 cm

Explanation

The near point distance equals the reciprocal of the amplitude in dioptres: 1/8.00 D = 0.125 m, or 12.5 cm. This assumes the amplitude is referred to the spectacle plane or eye and ignores any refractive correction.

Question 36Refraction, Binocular Vision and Accommodation

Which test is most appropriate for detecting a small-angle strabismus that may be missed on the cover test?

  1. The Brückner test
  2. The Worth 4-dot test Correct answer.
  3. The Hirschberg test
  4. The Maddox rod test

Explanation

The Worth 4-dot test assesses binocular sensory fusion and can reveal suppression or diplopia from small-angle deviations that are hard to see on cover testing. It evaluates the sensory consequences of the deviation rather than the motor angle directly.

Question 37Refraction, Binocular Vision and Accommodation

A 6-year-old child with a cycloplegic refraction of +4.00 DS in both eyes has an esotropia at near. Which management approach is most consistent with standard practice?

  1. Prescribe the full hyperopic correction and reassess alignment Correct answer.
  2. Prescribe a myopic overcorrection to stimulate accommodation
  3. Prescribe no correction and review in 12 months
  4. Prescribe bifocals as first-line therapy

Explanation

In accommodative esotropia associated with hyperopia, correcting the full cycloplegic refractive error reduces accommodative demand and often improves alignment. The child is then reviewed to assess the residual deviation before considering further options such as bifocals.

Question 38Refraction, Binocular Vision and Accommodation

Which of the following is the standard criterion for a diagnosis of amblyopia in a school-aged child with no visible ocular pathology?

  1. Best-corrected acuity of 6/9 or worse in one eye with an interocular difference of two or more lines Correct answer.
  2. A cycloplegic refraction of +1.00 DS in both eyes
  3. Best-corrected acuity of 6/6 in both eyes with a one-line difference
  4. Uncorrected acuity of 6/6 in each eye

Explanation

Amblyopia is defined by reduced best-corrected acuity in one or both eyes that cannot be attributed to structural abnormality, typically 6/9 or worse with an interocular difference of two or more lines. The reduction must persist with optimal refractive correction.

Question 39Refraction, Binocular Vision and Accommodation

A patient reports intermittent blur at near that clears when they look away and back. Which finding on binocular assessment would most suggest an accommodative insufficiency?

  1. A large exophoria at distance only
  2. A normal accommodative facility with plus lenses
  3. A reduced amplitude of accommodation for age with a normal accommodative response Correct answer.
  4. An increased near point of convergence with normal amplitude

Explanation

Accommodative insufficiency is characterised by an amplitude of accommodation below the expected value for age, often with a normal or reduced accommodative response and symptoms of near blur or asthenopia. Accommodative facility is typically reduced with minus lenses.

Question 40Refraction, Binocular Vision and Accommodation

Using the von Graefe technique, a 6 Δ base-out prism is placed before the right eye and a 12 Δ base-in prism before the left eye. The patient reports the target is aligned when the right eye prism is reduced to 2 Δ base-out. What is the near phoria?

  1. 8 Δ exophoria
  2. 8 Δ esophoria
  3. 4 Δ esophoria Correct answer.
  4. 4 Δ exophoria

Explanation

In von Graefe testing, the dissociating prism before one eye and the measuring prism before the other are compared. Here the 6 Δ base-out was reduced to 2 Δ base-out, meaning 4 Δ of base-in effect was needed to neutralise an esophoric deviation. The result is therefore 4 Δ esophoria.

Question 41Refraction, Binocular Vision and Accommodation

A patient has a near point of convergence of 15 cm and a near exophoria of 10 Δ with a reduced positive fusional vergence range. Which diagnosis is most likely?

  1. Basic esophoria
  2. Convergence insufficiency Correct answer.
  3. Accommodative excess
  4. Divergence excess

Explanation

A receded near point of convergence, near exophoria, and reduced positive fusional vergence are the classic triad of convergence insufficiency. Symptoms typically include near asthenopia, diplopia, and difficulty sustaining near tasks.

Question 42Refraction, Binocular Vision and Accommodation

A 10-year-old has a cycloplegic refraction of +1.00 DS in each eye and an esotropia of 20 Δ at near that reduces to 5 Δ at distance with correction. What is the most appropriate next step?

  1. Add a near bifocal to reduce the near deviation Correct answer.
  2. Increase the distance plus power by 1.00 D
  3. Prescribe a base-out prism to eliminate the near deviation
  4. Commence patching of the non-dominant eye

Explanation

A near esotropia that persists with full distance correction but is much smaller at distance is characteristic of a high accommodative convergence to accommodation (AC/A) ratio. A bifocal add reduces accommodative demand at near and is the standard next step.

Question 43Refraction, Binocular Vision and Accommodation

In a patient with a suspected unilateral cataract, which test would best help determine whether the patient has a dense suppression scotoma in the affected eye?

  1. The Worth 4-dot test at distance and near Correct answer.
  2. The cover-uncover test
  3. The near point of convergence
  4. The alternating cover test

Explanation

The Worth 4-dot test assesses simultaneous perception and fusion; a patient reporting only two or three lights indicates suppression of one eye. This is useful for identifying a suppression scotoma in the presence of media opacity.

Question 44Refraction, Binocular Vision and Accommodation

During retinoscopy, a with-movement reflex is observed in the horizontal meridian and a neutral reflex in the vertical meridian at 67 cm. Which statement best describes the refractive error?

  1. Simple myopia
  2. Mixed astigmatism
  3. With-the-rule astigmatism Correct answer.
  4. Against-the-rule astigmatism

Explanation

With-movement indicates hyperopia (or a less myopic meridian) relative to the working distance, while neutrality indicates that meridian is focused at the working distance. A with-movement in the horizontal meridian and neutrality vertically indicates with-the-rule astigmatism once the working distance is accounted for.

Question 45Refraction, Binocular Vision and Accommodation

A patient with a high AC/A ratio is being fitted with a bifocal. Which add is most appropriate?

  1. A +1.00 to +2.50 D add with the top of the segment at the lower lid margin Correct answer.
  2. A plano add with a base-out prism incorporated
  3. A -1.00 D add to stimulate accommodation
  4. A +3.00 to +4.00 D add with the segment top at the pupil

Explanation

For high AC/A esotropia, a bifocal add of about +1.00 to +2.50 D is typically used, with the segment top positioned at or slightly below the lower lid margin so the child looks through the add for near tasks. Higher adds are used only when lower adds fail to control the deviation.

Question 46Refraction, Binocular Vision and Accommodation

A patient reports diplopia when reading, and a cover test shows a small exophoria at near with a normal near point of convergence. Which finding would most suggest a decompensating exophoria rather than a convergence insufficiency?

  1. A high amplitude of accommodation for age
  2. A normal near point of convergence with reduced positive fusional vergence Correct answer.
  3. A reduced positive fusional vergence range at near with a receded near point of convergence
  4. A reduced negative fusional vergence range at near

Explanation

A decompensating exophoria may present with reduced positive fusional vergence despite a normal near point of convergence, whereas convergence insufficiency classically has a receded near point of convergence. The distinction guides whether vergence or accommodative therapy is prioritised.

Question 47Refraction, Binocular Vision and Accommodation

Which of the following best explains why cycloplegic refraction is preferred in young children with suspected accommodative esotropia?

  1. It determines the amplitude of accommodation
  2. It eliminates accommodative tone, revealing the full hyperopic error Correct answer.
  3. It assesses the near point of convergence
  4. It measures the AC/A ratio directly

Explanation

Cycloplegia paralyses the ciliary muscle, removing accommodative tone that can mask hyperopia during non-cycloplegic refraction. This reveals the full hyperopic error, which is essential for prescribing the correct correction in accommodative esotropia.

Question 48Refraction, Binocular Vision and Accommodation

A patient's retinoscopy at 50 cm shows a neutral reflex in all meridians. What spectacle prescription would be expected if the working distance is correctly accounted for?

  1. Plano Correct answer.
  2. +2.00 DS
  3. -2.00 DS
  4. +4.00 DS

Explanation

A neutral reflex at 50 cm means the eye is focused at the working distance, which corresponds to 2.00 D. Subtracting the working distance lens of +2.00 D from the neutral finding leaves a plano refraction.

Question 49Refraction, Binocular Vision and Accommodation

A patient with a recent onset of diplopia has a comitant esotropia of 15 Δ at distance and near. Which additional finding would most raise concern for a neurological cause?

  1. An incomitant deviation that varies with gaze direction Correct answer.
  2. A normal accommodation and near point of convergence
  3. A reduced amplitude of accommodation with normal pupils
  4. A longstanding history of intermittent exotropia

Explanation

Comitance suggests a longstanding or benign cause, whereas incomitance (a deviation that varies with gaze direction) suggests a restrictive or paretic aetiology and warrants neurological assessment. Acute onset with incomitance is a red flag.

Question 50Refraction, Binocular Vision and Accommodation

Which statement about the AC/A ratio is correct?

  1. It is the change in accommodation per dioptre of convergence
  2. It is the change in accommodative convergence per dioptre of accommodation Correct answer.
  3. It is the ratio of amplitude of accommodation to near point of convergence
  4. It is the ratio of near to distance phoria

Explanation

The AC/A ratio quantifies how much convergence (in prism dioptres) is produced per dioptre of accommodative effort. It is commonly estimated by the heterophoria method or the gradient method.