AIM • KMU EXAM PRACTICE

Topic 10 — Cataract: Types, Pathogenesis, Complications & Management

4th Year MBBS • Ophthalmology 👁️ • 20 A-type Single Best Answer MCQs

Question:

A 68-year-old man with an early lens opacity reports seeing two images of a distant light with the affected eye alone. Ocular alignment and retinal examination are normal. Which lens-related change best explains this complaint?

Reduced transmission of light through the entire lens

Different lens regions acquire unequal refractive properties

Progressive weakness of the supporting zonular fibres

Increased production of aqueous humour behind the iris

Reduced retinal sensitivity caused by ageing of the macula

Correct Answer:
Different lens regions acquire unequal refractive properties

Explanation: Irregular areas within a cataractous lens refract light differently, so more than one image may be formed in the affected eye.

Question:

A 65-year-old woman has peripheral radial cortical opacities on slit-lamp examination but relatively preserved central visual acuity. Which finding would most likely cause a substantial decline in her vision during progression?

Increasing pigmentation limited to the lens capsule

Shrinkage of the lens away from the pupillary area

Migration of the lens nucleus toward the posterior capsule

Extension of the cortical spokes into the central visual axis

Reduction in the refractive power of the corneal surface

Correct Answer:
Extension of the cortical spokes into the central visual axis

Explanation: Peripheral cortical opacities may initially spare central vision. Visual impairment becomes greater when the spokes extend into the visual axis.

Question:

Slit-lamp examination of a 75-year-old man reveals marked hardening and brown discoloration of the central lens. Which property of this part of the lens makes it particularly susceptible to these age-related changes?

It contains the oldest lens fibres exposed to prolonged compaction and protein change

It receives the greatest vascular supply from the ciliary circulation

It contains the highest concentration of aqueous-producing epithelial cells

It is exposed directly to inflammatory cells from the anterior chamber

It is continuously replaced by newly formed peripheral lens fibres

Correct Answer:
It contains the oldest lens fibres exposed to prolonged compaction and protein change

Explanation: The central nuclear fibres are the oldest lens fibres and undergo progressive compaction, protein modification and pigmentation with ageing.

Question:

A patient with gradually worsening vision is suspected of having an age-related cataract. The ophthalmologist wants to determine whether the main opacity is nuclear, cortical or posterior subcapsular and assess its density. Which examination provides the most useful information?

Visual-field examination

Ocular-movement assessment

Colour-vision assessment

Fundus examination alone

Slit-lamp examination of the lens

Correct Answer:
Slit-lamp examination of the lens

Explanation: Slit-lamp examination directly demonstrates the location, pattern and density of lens opacities and therefore helps classify the cataract.

Question:

A 64-year-old man with a cataract receives a new spectacle prescription. Refraction corrects part of his visual loss, but significant haziness remains. Which explanation best accounts for the incomplete improvement?

Spectacles increase the rate of progression of lens sclerosis

Spectacles cannot compensate for loss of retinal photoreceptors

Lens opacity causes light scatter in addition to refractive error

Lens opacity prevents the cornea from contributing refractive power

Spectacles reduce aqueous movement through the anterior chamber

Correct Answer:
Lens opacity causes light scatter in addition to refractive error

Explanation: Refraction can correct an optical focusing error, but it cannot eliminate the light scattering produced by an opaque lens.

Question:

A 61-year-old woman with a mild cataract can still perform her daily activities but finds reading difficult in dim surroundings. Her ophthalmologist recommends improved illumination together with updated spectacles. What is the intended role of these measures?

To prevent future biochemical alteration of crystallins

To improve usable vision while the cataract remains functionally acceptable

To reverse hydration of the lens cortex permanently

To reduce the risk of macrophage obstruction of the trabeculum

To restore complete transparency before later surgery

Correct Answer:
To improve usable vision while the cataract remains functionally acceptable

Explanation: Better illumination and appropriate spectacles can provide temporary functional improvement in mild cataract without removing the lens opacity.

Question:

A patient has agreed to cataract extraction with intraocular lens implantation. Before surgery, specific ocular measurements are taken. What is the principal purpose of these measurements?

To grade the inflammatory response to the cataract

To measure the degree of lens-protein leakage

To identify whether the cataract is cortical or nuclear

To predict whether postoperative uveitis will develop

To select an appropriate refractive power for the intraocular lens

Correct Answer:
To select an appropriate refractive power for the intraocular lens

Explanation: Preoperative ocular measurements are used to calculate the IOL power required to provide appropriate postoperative optical correction.

Question:

During counseling before cataract surgery, a student asks why an artificial intraocular lens is implanted after removal of the cataractous natural lens. Which explanation is most appropriate?

It replaces much of the focusing power lost when the natural lens is removed

It increases aqueous drainage through the trabecular meshwork

It prevents age-related changes in the corneal epithelium

It restores damaged retinal photoreceptors after cataract surgery

It prevents inflammatory cells entering the anterior chamber

Correct Answer:
It replaces much of the focusing power lost when the natural lens is removed

Explanation: Cataract extraction removes an important refractive structure. The implanted IOL restores much of the eye’s lost focusing power.

Question:

During cataract surgery, the surgeon breaks the hardened lens nucleus into small fragments before aspirating the lens material through a small incision. Which operative feature identifies phacoemulsification?

Removal of the lens together with the complete capsule

Manual delivery of the intact nucleus without fragmentation

Laser destruction of the opaque posterior capsule

Ultrasound energy used to fragment the cataractous nucleus

Removal of the vitreous before implantation of the lens

Correct Answer:
Ultrasound energy used to fragment the cataractous nucleus

Explanation: Phacoemulsification uses ultrasound energy to break the nucleus into removable fragments through a relatively small incision.

Question:

A patient undergoes cataract surgery in which the nucleus is manually removed through a self-sealing incision without ultrasound fragmentation, followed by IOL implantation. Which procedure has been performed?

Phacoemulsification

Intracapsular lens removal

Manual small-incision cataract surgery

Posterior capsular laser treatment

Anterior chamber drainage surgery

Correct Answer:
Manual small-incision cataract surgery

Explanation: Manual small-incision cataract surgery removes the nucleus through a self-sealing incision without phacoemulsification.

Question:

A surgeon removes the lens nucleus and cortex through an extracapsular technique but deliberately leaves the posterior capsule in place. Which operation best matches this description?

Extracapsular cataract extraction

Trabecular drainage surgery

Corneal transplantation

Vitrectomy with lens preservation

Anterior chamber paracentesis

Correct Answer:
Extracapsular cataract extraction

Explanation: In extracapsular extraction the cataractous nucleus and cortex are removed while the posterior capsule is preserved.

Question:

During phacoemulsification, the posterior part of the lens capsule is preserved and an artificial lens is placed within the remaining capsular structure. What is the major advantage of retaining this capsule?

It increases the production of aqueous humour

It prevents progression of retinal degeneration

It restores the transparency of remaining nuclear fibres

It permanently increases the diameter of the pupil

It provides stable support for a posterior chamber intraocular lens

Correct Answer:
It provides stable support for a posterior chamber intraocular lens

Explanation: Preservation of the posterior capsule and capsular bag provides an appropriate anatomical support for IOL implantation.

Question:

A 70-year-old man is being evaluated before cataract surgery. In addition to visual acuity and lens examination, the ophthalmologist carefully assesses the pupil and anterior segment. What is the main purpose of this part of the examination?

To determine the biochemical composition of crystallin proteins

To identify additional ocular abnormalities that may influence management

To measure the amount of light scattered by individual lens fibres

To establish whether the lens contains soluble or insoluble proteins

To determine whether spectacle correction will reverse the lens opacity

Correct Answer:
To identify additional ocular abnormalities that may influence management

Explanation: Preoperative anterior-segment and pupil assessment helps identify coexisting abnormalities that can influence the surgical plan or expected outcome.

Question:

Two patients have similar measured visual acuity from cataract. One reports major difficulty recognizing low-contrast objects and severe visual discomfort in daily activities, while the other functions well. Which interpretation is most appropriate?

Visual acuity precisely predicts all functional effects of cataract

Both patients must have identical lens morphology because acuity is equal

Contrast loss implies that the cataract has become hypermature

Functional impairment can be greater than the acuity measurement suggests

The more symptomatic patient must have a secondary retinal disorder

Correct Answer:
Functional impairment can be greater than the acuity measurement suggests

Explanation: Cataract can impair contrast and produce glare even when measured acuity remains relatively preserved, so functional assessment is important.

Question:

An elderly patient with a very long-standing degenerative cataract is found to have a shrunken lens and wrinkled capsule. The ophthalmologist also notes reduced stability of the lens. Which additional age-related change best explains this finding?

Increasing vascularization of the lens nucleus

Progressive thickening of the retinal nerve fibre layer

Weakening of the structures supporting the degenerating lens

Increased aqueous production by the posterior lens capsule

Increased attachment between the lens and corneal endothelium

Correct Answer:
Weakening of the structures supporting the degenerating lens

Explanation: Advanced hypermature degeneration can be associated with weakening of lens-supporting structures and reduced lens stability.

Question:

During an examination discussion, a student lists nuclear, cortical, posterior subcapsular and mature cataract as four equivalent anatomical types of age-related cataract. Which correction is most accurate?

Nuclear cataract is a stage, while the other three are anatomical types

Cortical cataract is a complication rather than an anatomical type

Posterior subcapsular cataract represents only a hypermature stage

All four terms describe the anatomical position of lens opacity

Mature describes an advanced stage rather than a site-based cataract type

Correct Answer:
Mature describes an advanced stage rather than a site-based cataract type

Explanation: Nuclear, cortical and posterior subcapsular terms describe anatomical patterns, whereas mature and hypermature describe advanced stages.

Question:

A patient with a relatively early cataract has near-normal Snellen acuity but complains that faces and objects appear washed out and poorly defined. Which optical disturbance best explains this complaint?

Scattered light reduces the contrast of the retinal image

Reduced aqueous production lowers retinal illumination

The lens opacity directly decreases optic-nerve conduction

Cortical hydration permanently reduces pupillary diameter

Nuclear sclerosis produces retinal photoreceptor degeneration

Correct Answer:
Scattered light reduces the contrast of the retinal image

Explanation: Lens opacity scatters light and reduces image contrast, so visual quality may deteriorate before severe loss of measured acuity occurs.

Question:

A 72-year-old patient has complete opacity of the lens but no cortical liquefaction, lens shrinkage or wrinkling of the capsule. Which interpretation best fits these findings?

The cataract has developed phacolytic glaucoma

The lens has progressed to the hypermature degenerative stage

The opacity represents an isolated posterior subcapsular cataract

The lens is mature but has not yet developed hypermature degeneration

The findings indicate early peripheral cortical cataract

Correct Answer:
The lens is mature but has not yet developed hypermature degeneration

Explanation: A mature cataract is completely opaque. Liquefaction, shrinkage and capsular wrinkling indicate further progression to hypermaturity.

Question:

An elderly patient has a hypermature cataract with cortical liquefaction and a wrinkled capsule but no pain, redness or elevation of intraocular pressure. Which conclusion is most appropriate?

Absence of glaucoma means that the cataract is still immature

Hypermaturity represents advanced degeneration that can exist before a secondary complication develops

A hypermature lens must produce inflammation before cortical liquefaction occurs

Cortical liquefaction indicates that the lens opacity has started to resolve

Normal intraocular pressure excludes significant age-related cataract

Correct Answer:
Hypermaturity represents advanced degeneration that can exist before a secondary complication develops

Explanation: Hypermature cataract describes advanced lens degeneration. Lens-induced glaucoma or inflammation is a possible complication, not a defining requirement.

Question:

A 59-year-old woman with an early age-related cataract asks whether treatment must begin with an operation. Her corrected vision remains sufficient for her usual activities and no ocular complication is present. Which counseling approach best reflects cataract management principles?

Surgery is required whenever any lens opacity can be demonstrated

Treatment should be postponed until complete lens opacity develops

Conservative visual support is appropriate until functional impairment or another indication develops

The cataract should first be treated with long-term topical corticosteroids

Early surgery is required to prevent every cataract from becoming hypermature

Correct Answer:
Conservative visual support is appropriate until functional impairment or another indication develops

Explanation: Mild cataract with adequate visual function may be managed with optical measures and observation; surgery is considered when clinically indicated.