Optometry Accommodation Quiz

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Questions and Answers

What level of accommodation is required for an emmetropic patient to focus on an object at 40cm?

2.5D (correct)

What is the far point for a myope with a prescription of -6.00DS?

-6m

1.67m (correct)

-1m

For an uncorrected +3.00D hyperopic patient looking at an object at 25cm, what level of accommodation is needed?

8D (correct)

What level of accommodation is required for an uncorrected -5.00D myope to see an object at 10cm?

10D Signup and view all the answers

What is the far point for a -6.00DS myope with 8D of accommodation?

3.33m Signup and view all the answers

What is the primary method for assessing amplitude of accommodation in pre-presbyopes?

Push-up/pull-down method Signup and view all the answers

What typical range of accommodative lag is generally considered normal?

0.50-0.75D Signup and view all the answers

Which condition can potentially lead to asthenopia when the amplitude of accommodation is reduced?

Chronic fatigue Signup and view all the answers

What is a common associated condition with accommodative insufficiency?

Convergence insufficiency Signup and view all the answers

Which factor might contribute to reduced amplitude of accommodation?

Excessive near work Signup and view all the answers

What is the implication of high AC/A ratio in relation to accommodative function?

They converge too much while accommodating Signup and view all the answers

Which of the following is an effective treatment approach for accommodative anomalies?

Plus lenses or multis Signup and view all the answers

Asthenopia can be caused by which of the following underlying conditions?

Latent hyperopia Signup and view all the answers

What does the accommodation stimulus signify for an emmetropic individual when looking at a near object?

It represents the reciprocal of the target distance in meters. Signup and view all the answers

Which statement accurately describes the amplitude of accommodation (AOA)?

AOA declines significantly after the age of 60. Signup and view all the answers

What is one effect of an increased pupil diameter on accommodation?

Decreased depth of field. Signup and view all the answers

What does the term 'range of accommodation' refer to?

The distance between the near and far point of vision. Signup and view all the answers

How is the subjective amplitude of accommodation measured?

Through a subjective depth of focus assessment. Signup and view all the answers

What happens to subjective amplitude of accommodation (AOA) at the age of 60?

It is drastically reduced but does not reach zero. Signup and view all the answers

What is the primary purpose of using a plus lens in correcting simple hyperopia?

To ensure point focus on or just behind the retina. Signup and view all the answers

What is NOT true regarding the effect of aging on accommodation?

Subjective depth of field remains unaffected by age. Signup and view all the answers

What happens to the focal point in simple myopia when accommodation is applied?

The near point moves closer to the patient's eye. Signup and view all the answers

How does the mechanism of accommodation affect patients with simple hypermetropia?

It increases the plus power required for clear vision. Signup and view all the answers

Which factor is NOT essential for calculating the required accommodation in a patient?

Quality of ocular motility. Signup and view all the answers

What is the primary purpose of measuring the amplitude of accommodation (AoA)?

To understand the range at which near objects can be focused. Signup and view all the answers

What would be the impact of a weaker dioptric power in an eye that is hypermetropic?

It leads to a shift of the near point further away. Signup and view all the answers

In accommodative demand, what is meant by 'far point'?

The furthest distance at which an object appears blurred without corrective lenses. Signup and view all the answers

What effect does the application of plus correcting lenses have on hypermetropic patients?

It reduces the accommodation requirement. Signup and view all the answers

Which statement correctly describes the relationship between dioptric power and correcting lenses?

A stronger lens is necessary for myopic conditions. Signup and view all the answers

Why is understanding the range of accommodation important for patient care?

It guides the selection of appropriate spectacles. Signup and view all the answers

What is the primary reason for measuring accommodative demand?

To determine how much accommodation is required for clear vision. Signup and view all the answers

Study Notes

Nut-Free Zone

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Accommodation and Eye Examination

Lecture is being recorded as part of a content capture project
Recording will be available on the module DLE pages
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Lecture title: Accommodation and Eye Examination, course OPT505, lecturer Ellie Livings

Intended Learning Outcomes

Understand the role, purpose, and mechanism of accommodation
Understand the relevance of accommodation in ametropia and its correction
Know how to measure accommodation near point (AoA)
Understand far point, range of accommodation, and accommodative demand
Know how to calculate accommodation required and range of accommodation

Relevant GOC LO

Undertakes safe and appropriate ocular examinations
Informs clinical decision-making within individual scope of practice
Refractive management
Pediatrics
Patients with learning disabilities & complex needs
Occupational optometry
Interprets the results of history-taking and examination of the refractive and ocular motor status
Manages and dispenses appropriate spectacles
Adapts practice environment and activity for individual needs
Patient health informs clinical decision-making and care management plans

Recap Optics

Simple Myopia: Dioptric power of the eye is too strong, axial length is too long, point focus is in front of the retina, blur circle
Simple Hypermetropia: Dioptric power of the eye is too weak, axial length is too short, point focus is theoretically behind the eye, blur circle

Scale Model of Eye

Cornea thickness, lens thickness, cornea to lens distance
Radius
Power (mm2)
Various refractive indices (n) of eye components

Dioptric Power of Eye and Correcting Lenses

Dioptric power measurements are shown on a number line
Corrective lens needed for too-weak or too-strong dioptric power

Relaxed/Accommodated Lens

Diagrams illustrating the relaxed and accommodated states of the lens
Ciliary muscles, zonular fibers, and suspensory ligaments play roles in accommodation
Far point and near point

Human Eye Accommodation Range

Normal accommodation range (25 cm)
Nearsighted accommodation range (18 cm)
Farsighted accommodation (31 cm)
Relaxed eye muscles

Accommodation over time

Accommodation amplitude (AOA) declines with age.
AOA is reduced at age 60, but depth of field/focus keeps subjective AOA from being the same as objective AOA.
Distance Rx is corrected to measure the subjective AOA.

Depth of (object ) Field & Depth of (image) Focus

Range of object distances where the circle of confusion is small enough to perceive a sharp image
Range of image distances where the image of an improperly focused object is acceptably sharp
The circle of confusion is the area of the retina stimulated by light from a point on an object, so the larger the circle, the more blurry the image

The Size of the Blur Circle

Blur circle depends on focussing error, pupil size, axial length

Accommodation

Amplitude of Accommodation (AOA) is the maximum amount of accommodation an individual can exert and is measured in diopters.
AOA can be measured subjectively or objectively using RAF rule.

How do we measure Amplitude (AoA)?

Push-up/pull-down method (using a RAF rule/Mallet unit)
Minus lens technique
Accommodative facility
Lens rock
Accommodative lag
Dynamic retinoscopy

AOA: real life

People can't hold maximum accommodation for very long periods, and overexertion can cause asthenopia (eye fatigue).
When AOA is insufficient, near tasks become difficult.
Rule of thumb: a patient can exert about two-thirds of their accommodative amplitude.
Graph showing changes in accommodation over time based on age

AOA – Clinical Significance

Symptoms relating to reduced AOA, such as headache and eye strain, are often associated with uncorrected hyperopia.
Possible causes include latent hyperopia, medication, pathology (uveitis, etc), traumas, down's syndrome and cerebral palsy, stress, drug/alcohol misuse, and cataract

Accommodative Lag

Measure with near retinoscopy (dynamic retinoscopy)
Normal lag is 0.50–0.75D.
Larger lag can be linked to myopic progression; hyperopic defocus during near work can increase myopia.
Lag is associated with near esophoria in young myopes

Accommodative Anomalies

Combined accommodative and convergence insufficiency is common
Accommodative insufficiency/infacility/fatigue can lead to the use of exercises, plus lenses, or multi-focal lenses.
(AC/A ratio) how convergence is changed from prism dioptres related to 1 diopter of accommodation. The high number means that the eyes may converge too much when accommodating

Case Scenarios (I - VI)

Questions regarding accommodation levels required for various scenarios (emmetropic patient, myopic patient)

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Description

Test your knowledge on the level of accommodation required for various refractive errors in ophthalmology. This quiz covers emmetropia, myopia, and hyperopia, focusing on calculating accommodation levels for different distances. Perfect for students studying optometry or eye care principles.