Optometrists Registration Assessment (Hong Kong)

What is the primary active transport mechanism located in the corneal endothelium responsible for maintaining corneal deturgescence?

• ANa+/K+ ATPase pump
• BCa2+ ATPase pump
• CCl-/HCO3- exchanger
• DGlucose active transporter

Which nerve branch provides the primary sensory innervation to the cornea, and which pathway does it travel?

• ALong ciliary nerves from the ophthalmic division of the trigeminal nerve (CN V1)
• BShort ciliary nerves from the maxillary division of the trigeminal nerve (CN V2)
• CLacrimal nerve from the facial nerve (CN VII)
• DZygomaticotemporal nerve from the mandibular division of the trigeminal nerve (CN V3)

The Y-sutures of the human crystalline lens are formed by the abutting of lens fibers. What is the orientation of these Y-sutures anteriorly and posteriorly in the embryonic/fetal nucleus?

• AErect Y anteriorly, inverted Y posteriorly
• BInverted Y anteriorly, erect Y posteriorly
• CErect Y both anteriorly and posteriorly
• DInverted Y both anteriorly and posteriorly

The outer layers of the retina, specifically the photoreceptors, receive their oxygen and nutrient supply primarily from which vascular network?

• AChoriocapillaris
• BCentral retinal artery
• CCircle of Zinn-Haller
• DAnterior ciliary arteries

Where is the primary site of resistance to aqueous humor outflow in the trabecular meshwork pathway?

• AJuxtacanalicular tissue (cribriform meshwork)
• BUveal meshwork
• CCorneoscleral meshwork
• DInner wall of Schlemm's canal

A patient exhibits a complete palsy of the left trochlear nerve (CN IV). Which extraocular muscle is affected, and what is its primary action in the primary position of gaze?

• ALeft superior oblique - intorsion
• BLeft superior oblique - extorsion
• CLeft superior rectus - elevation
• DLeft lateral rectus - abduction

Optic nerve fibers originating from the nasal retina of the right eye cross at the optic chiasm to project to which specific layers of the contralateral lateral geniculate nucleus (LGN)?

• ALayers 1, 4, and 6 of the left LGN
• BLayers 2, 3, and 5 of the left LGN
• CLayers 1, 4, and 6 of the right LGN
• DLayers 1, 2, and 3 of the left LGN

Which nucleus in the midbrain receives afferent pupillary fibers first in the pupillary light reflex arc?

• APretectal olivary nucleus
• BEdinger-Westphal nucleus
• CCiliary ganglion
• DSuperior colliculus

The lipid layer of the tear film is primarily secreted by which glands, and what is its main physiological function?

• AMeibomian glands - preventing evaporation of the aqueous phase
• BGlands of Krause - producing the mucous phase
• CGlands of Wolfring - producing the aqueous phase
• DLacrimal gland - providing lubrication

What is the source of the transient amplifying cells that replenish the corneal epithelial cells, and where are they located?

• AStem cells located in the limbal palisades of Vogt
• BStem cells located in the central basal layer
• CStem cells located in the episclera
• DStem cells located in the conjunctival fornix

What anatomical structures form the outer blood-retinal barrier?

• ATight junctions (zonula occludens) of the retinal pigment epithelium (RPE)
• BTight junctions of the retinal capillary endothelial cells
• CDesmosomes of the photoreceptor outer segments
• DGap junctions of the Muller cells

A complete lesion involving the right optic tract will result in which type of visual field defect?

• ALeft homonymous hemianopia
• BRight homonymous hemianopia
• CBitemporal hemianopia
• DLeft homonymous superior quadrantanopia

According to the Helmholtz theory of accommodation, what changes occur in the ciliary muscle, zonules, and crystalline lens shape during accommodation?

• ACiliary muscle contracts, zonules relax, lens becomes more spherical
• BCiliary muscle relaxes, zonules contract, lens flattens
• CCiliary muscle contracts, zonules contract, lens flattens
• DCiliary muscle relaxes, zonules relax, lens becomes more spherical

The corneal stroma consists of regularly arranged collagen fibrils. What is the predominant type of collagen in the corneal stroma?

• AType I collagen
• BType II collagen
• CType IV collagen
• DType VII collagen

In the dark, photoreceptors are in a depolarized state due to the dark current. What occurs immediately after light absorption by rhodopsin to initiate hyperpolarization?

• AActivation of transducin which activates cGMP phosphodiesterase, leading to decreased cGM…
• BOpening of potassium leak channels in the inner segment
• CDirect influx of sodium ions through cyclic nucleotide-gated channels
• DImmediate release of glutamate neurotransmitter at the synapse

The macular pigments lutein and zeaxanthin are concentrated in which retinal layer at the fovea, serving as blue-light filters?

• AHenle's fiber layer and inner plexiform layer
• BPhotoreceptor outer segment layer
• CGanglion cell layer
• DRetinal pigment epithelium (RPE)

The ciliary epithelium consists of two cellular layers. What is the anatomical orientation and pigmentation of these layers?

• AOuter pigmented layer (basal lamina facing stroma) and inner non-pigmented layer (basal l…
• BOuter non-pigmented layer and inner pigmented layer
• CBoth layers are pigmented
• DBoth layers are non-pigmented

What is the primary collagen type and the major glycosaminoglycan (GAG) present in the vitreous humor?

• AType II collagen and hyaluronic acid
• BType I collagen and chondroitin sulfate
• CType IV collagen and heparan sulfate
• DType III collagen and dermatan sulfate

The near response triad consists of which three physiological mechanisms triggered by viewing a near object?

• AAccommodation, convergence, and pupillary miosis
• BAccommodation, divergence, and pupillary mydriasis
• CCycloplegia, convergence, and pupillary miosis
• DAccommodation, cycloversion, and pupillary mydriasis

The dark adaptation curve shows a biphasic shape. What does the 'rod-cone break' represent on this curve?

• AThe point during dark adaptation (around 7-10 minutes) where rod sensitivity exceeds cone…
• BThe complete depletion of rhodopsin in the retina
• CThe recovery of 100% of cone photopigment
• DThe transition from photopic to mesopic vision

During subjective refraction, when refining the cylinder axis using a Jackson Cross Cylinder (JCC), how should the JCC handle be oriented relative to the patient's cylinder axis?

• AThe handle of the JCC must be aligned parallel to the patient's cylinder axis
• BThe handle of the JCC must be oriented at 45 degrees to the patient's cylinder axis
• CThe handle of the JCC must be oriented at 90 degrees to the patient's cylinder axis
• DThe handle of the JCC must be oriented at 30 degrees to the patient's cylinder axis

During retinoscopy at a working distance of 67 cm, neutrality is achieved in all meridians with a +3.00 DS lens. What is the patient's net refractive error?

• A+1.50 DS
• B+2.00 DS
• C+4.50 DS
• D+3.00 DS

A patient wears a spectacle correction of -6.00 DS in both eyes. The patient's optical centers are accidentally positioned 3 mm wider than their true interpupillary distance (IPD). What is the magnitude and direction of the induced prism in each eye?

• A0.90 prism diopters base-in
• B0.90 prism diopters base-out
• C1.80 prism diopters base-in
• D1.80 prism diopters base-out

A patient's near phoria measures 4 prism diopters exophoria at 40 cm. When a -1.00 DS lens is placed binocularly, the phoria changes to 1 prism diopter esophoria. What is the patient's gradient AC/A ratio?

• A5 prism diopters per diopter
• B3 prism diopters per diopter
• C4 prism diopters per diopter
• D2 prism diopters per diopter

What is the optical basis of the Humphriss Immediate Contrast test for binocular balancing?

• ASuspending foveal vision in the non-tested eye using a +0.75 DS fogging lens while mainta…
• BUsing polarized filters to present separate targets to each eye under binocular conditions
• CUsing a red-green filter to dissociate the eyes using chromatic aberration
• DApplying a vertical prism to create diplopia and allow comparative alignment

A patient has axial anisometropia. Eye 1 is emmetropic (Plano) and Eye 2 has -4.00 DS of myopia. If corrected with spectacles at a vertex distance of 15 mm, what is the approximate difference in retinal image size (aniseikonia) between the two eyes?

• AThe image in Eye 2 will be approximately 6% smaller than in Eye 1
• BThe image in Eye 2 will be approximately 6% larger than in Eye 1
• CThe image in Eye 2 will be approximately 12% smaller than in Eye 1
• DThe retinal image sizes will remain exactly equal in both eyes

A patient's spectacle refraction is -8.00 DS at a vertex distance of 12 mm. What is the required power of the contact lens for this patient, rounded to the nearest standard step?

• A-7.25 DS
• B-8.75 DS
• C-8.00 DS
• D-6.75 DS

During Monocular Estimation Method (MEM) dynamic retinoscopy at a target distance of 40 cm, you observe a 'with' motion reflex. What does this finding indicate, and how is it quantified?

• AAccommodative lag (under-accommodation); quantified by placing brief plus lenses until ne…
• BAccommodative lead (over-accommodation); quantified by placing brief minus lenses until n…
• CAccommodative spasm; quantified by cycloplegic drops
• DHigh exophoria at near; quantified by base-in prisms

A patient has a near phoria of 12 exophoria and a positive fusional vergence (PFV) range of 12 blur, 18 break, and 10 recovery. According to Sheard's criteria, what prism prescription is required for comfortable near vision?

• A4 prism diopters base-in
• B2 prism diopters base-in
• C6 prism diopters base-out
• DNo prism is required

What is the primary clinical purpose of using a polarized Mallett unit in binocular vision testing?

• ATo measure the associated phoria (the minimum prism required to reduce fixation disparity…
• BTo measure the absolute angle of strabismus under complete dissociation
• CTo detect the presence of a relative afferent pupillary defect
• DTo measure visual acuity differences under polarized lighting conditions

Why is the calculated AC/A ratio typically larger than the gradient AC/A ratio in clinical measurements?

• AThe calculated method is influenced by proximal convergence due to the change in target d…
• BThe gradient method is artificially inflated by the use of cycloplegic agents during test…
• CThe calculated method does not account for the patient's interpupillary distance (IPD)
• DThe gradient method is affected by prism adaptation during the test

A patient fails the monocular accommodative facility test using +/-2.00 DS flipper lenses, showing significant difficulty only when attempting to clear the +2.00 DS side. What does this finding indicate?

• AAccommodative excess (difficulty relaxing accommodation)
• BAccommodative insufficiency (difficulty stimulating accommodation)
• CPresbyopia
• DIll-sustained accommodation

A patient has a best-corrected visual acuity of 6/12 on a standard Snellen chart. What is the equivalent visual acuity in LogMAR notation?

• A+0.30 LogMAR
• B+0.18 LogMAR
• C+0.20 LogMAR
• D+0.60 LogMAR

What is the key clinical advantage of using a random-dot stereotest (e.g., Randot) compared to a local stereotest (e.g., Titmus circles)?

• ARandom-dot tests eliminate monocular cues, preventing patients with monocular vision from…
• BRandom-dot tests measure only vertical binocular disparity
• CRandom-dot tests do not require the use of polarized or anaglyphic glasses
• DRandom-dot tests are easier to perform on toddlers and non-verbal children

How does the unaccommodated human eye optically compensate for the positive spherical aberration of the cornea to optimize retinal image quality?

• AThrough the peripheral flattening of the cornea and the gradient index (GRIN) profile of…
• BBy increasing the iris aperture size to allow peripheral light rays to bypass the lens
• CUsing the negative spherical aberration of the vitreous humor
• DThrough pupillary dilation under bright illumination

During Von Graefe phoria testing in a phoropter, what are the standard prism setups used to measure horizontal phoria?

• A6 prism diopters Base-Up/Down in one eye (dissociating), and 12 prism diopters Base-In/Ou…
• B12 prism diopters Base-In in one eye, and 6 prism diopters Base-Down in the other eye, bo…
• C10 prism diopters Base-Out in both eyes to stimulate maximum convergence
• D6 prism diopters Base-In in both eyes to align the horizontal targets

According to Knapp's Law, what is the theoretical optical recommendation for correcting axial anisometropia versus refractive anisometropia to minimize aniseikonia?

• ACorrect axial anisometropia with spectacles placed at the anterior focal point of the eye…
• BCorrect axial anisometropia with contact lenses; correct refractive anisometropia with sp…
• CCorrect both axial and refractive anisometropia with contact lenses to reduce prismatic e…
• DCorrect both axial and refractive anisometropia with spectacles to preserve spatial local…

The duochrome (red-green) test used during subjective refraction refinement is based on which optical property of the human eye?

• ALongitudinal chromatic aberration
• BSpherical aberration of the cornea
• CRadial astigmatism of the crystalline lens
• DPolarization changes in the vitreous humor

What is the formula for the calculated AC/A ratio, where PD is pupillary distance in cm, Hn is near deviation, Hd is distance deviation, and D is near fixation distance in diopters?

• AAC/A = PD + (Hn - Hd) / D
• BAC/A = PD - (Hn - Hd) / D
• CAC/A = (Hn - Hd) / (PD * D)
• DAC/A = PD + D * (Hn - Hd)

Transpose the spectacle prescription -2.25 DS / -1.75 DC x 085 to plus-cylinder form, and calculate the spherical equivalent power.

• A-4.00 DS / +1.75 DC x 175; Spherical Equivalent = -3.125 DS
• B-4.00 DS / +1.75 DC x 175; Spherical Equivalent = -3.00 DS
• C-2.25 DS / +1.75 DC x 175; Spherical Equivalent = -3.125 DS
• D-4.00 DS / -1.75 DC x 175; Spherical Equivalent = -3.125 DS

In rigid gas permeable (RGP) contact lens fitting, if you flatten the base curve of the lens by 0.10 mm while keeping the overall diameter constant, how does this affect the sagittal depth of the lens and the power of the tear lens?

• ASagittal depth decreases; the tear lens becomes more negative (minus tear lens)
• BSagittal depth increases; the tear lens becomes more positive (plus tear lens)
• CSagittal depth decreases; the tear lens becomes more positive (plus tear lens)
• DSagittal depth increases; the tear lens becomes more negative (minus tear lens)

A contact lens material has a permeability (Dk) of 90 Barrers. If the central thickness of a -3.00 DS lens made of this material is 0.09 mm, what is the oxygen transmissibility (Dk/t) of the lens?

• A100 x 10^-9 (cm/s)(ml O2/ml * mmHg)
• B10 x 10^-9 (cm/s)(ml O2/ml * mmHg)
• C81 x 10^-9 (cm/s)(ml O2/ml * mmHg)
• D90 x 10^-9 (cm/s)(ml O2/ml * mmHg)

A patient is fitted with a soft toric contact lens with a prescription of Plano / -1.50 DC x 180. During evaluation, the lens stabilizes with the orientation mark rotated 10 degrees clockwise (to the observer's right). According to the LARS rule, what cylinder axis should be ordered?

• A170 degrees
• B010 degrees
• C180 degrees
• D090 degrees

What is the primary clinical goal of the 'three-point touch' fitting philosophy for RGP contact lenses in patients with keratoconus?

• ATo distribute lens weight between the corneal apex and the peripheral cornea to avoid exc…
• BTo place all the lens weight on the central corneal apex to flatten the cone
• CTo clear the central cornea entirely to prevent any apical contact
• DTo maximize peripheral tear exchange by flattening the outer lens periphery

What is the primary etiology of contact lens-induced Giant Papillary Conjunctivitis (GPC) in soft contact lens wearers?

• AMechanical irritation from the lens edge/deposits combined with an immunological hypersen…
• BAn active bacterial infection of the tarsal conjunctiva by Staphylococcus epidermidis
• CHypoxia-induced hypertrophy of the conjunctival stroma
• DAn allergic reaction to the chemical preservatives present in multi-purpose saline soluti…

What epithelial changes occur in the central and mid-peripheral cornea during overnight orthokeratology to achieve myopia reduction?

• ACentral corneal epithelial cell thinning (compression) and mid-peripheral epithelial thic…
• BCentral corneal epithelial thickening and mid-peripheral epithelial thinning
• CStromal thinning centrally and stromal thickening in the periphery
• DUniform thinning of the corneal epithelium across the entire horizontal meridian

What is the most common risk factor associated with contact lens-related Acanthamoeba keratitis?

• AExposure of contact lenses or lens cases to tap water, swimming pools, or hot tubs
• BUsing daily disposable contact lenses instead of monthly replacement lenses
• COver-wearing high-oxygen-transmissibility silicone hydrogel lenses
• DHaving a high amount of corneal astigmatism prior to lens fitting