2024.07.06-Visual System and Colour Vision Part 1

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Questions and Answers

What is the typical value range for contact lenses compared to spectacles?

-0.75 to -1.0 Dioptres below spectacles

-0.5 to -0.75 Dioptres below spectacles

-0.25 to -0.5 Dioptres below spectacles (correct)

Equal to the value of spectacles

How many optotypes must an applicant correctly identify to rate their visual acuity as seen?

6 (correct)

What is the required binocular near visual acuity for Class 2 at a distance of 30-50 cm?

N3 (0.9)

N5 (0.7) (correct)

N4 (0.8)

N6 (0.6)

In the context of visual acuity exams, what does the acronym ICAO refer to?

International Civil Aviation Organization Signup and view all the answers

What is the maximum astigmatism that can be corrected with regular contact lenses?

1 diopter Signup and view all the answers

What condition is characterized by the eye being too short and the focus laying behind the retina?

Hyperopia Signup and view all the answers

Which method is NOT commonly used for testing color vision?

Retinoscopy Signup and view all the answers

At what near point measurement is accommodation around 10 diopters expected for a 26-year-old?

9 cm Signup and view all the answers

What should be considered when assessing visual acuity for aviation duties?

Both corrections for color vision deficiencies and visual acuity Signup and view all the answers

Which condition results in difficulty seeing objects clearly at a distance?

Myopia Signup and view all the answers

What does orthophoria indicate regarding eye axes?

Both eye axes are balanced regardless of binocular vision. Signup and view all the answers

Which statement about stereo vision is true?

It allows for accurate spatial recognition and distance judgment. Signup and view all the answers

What is the significance of binocular vision as indicated by stereotests?

If there is stereo vision, it guarantees binocular vision exists. Signup and view all the answers

Which examination is deemed necessary if there is any decrease in visual acuity?

Routine eye examination. Signup and view all the answers

What should be included in a comprehensive eye examination?

History-taking and ocular motility evaluation. Signup and view all the answers

In a situation of vision distance limitation (VDL), what is required?

Using corrective lenses and keeping a spare set of spectacles. Signup and view all the answers

What is the purpose of the papilla in funduscopy?

To provide a view of the optic nerve head. Signup and view all the answers

When must contact lenses be declared appropriate for use?

Only after approval by an AME or AeMC. Signup and view all the answers

What condition must be checked during a routine eye examination?

Examination of external eye anatomy. Signup and view all the answers

What defines heterophoria?

A latent tropia that is considered normal under certain values. Signup and view all the answers

Study Notes

Overview of the Visual System and Colour Vision

Critical for Aeromedical Examiners (AMEs) to understand eye anatomy, visual acuity assessment, and related ophthalmological examination techniques.
Essential ability to determine visual fitness related to aviation duties, including colour vision and ocular health.

Eye Anatomy and Vision Issues

Emmetropia: Normal vision where light focuses directly on the retina.
Hyperopia (Farsightedness): Eye is too short; corrective lenses are converging.
Myopia (Nearsightedness): Eye is too long; corrective lenses are diverging.
Astigmatism: Distorted vision due to irregular curvature of the cornea or lens.
Presbyopia: Age-related difficulty in focusing on near objects due to loss of elasticity in the lens.

Visual Acuity and Examination Procedures

Testing Methods: Includes direct vision charts like Landoltring, near visual acuity charts, and certification tests for monocular and binocular vision.
Visual Acuity Standards: Class 2 requirements mandate monocular acuity > 0.5 and binocular acuity > 0.7.
Assessment of near, intermediate, and distant vision is crucial at revalidation for Class 2.

Colour Vision Testing

Crucial for pilots; methods include Ishihara plates, lantern tests, and anomaloscopy.
Colour deficiency affects approximately 8% of males, often related to red/green vision.
First 15 Ishihara plates must be identified correctly; failures lead to further evaluations and limitations.

Accommodation and Convergence

Accommodation: Ability of the eye to adjust focus on near objects; changes with age and significantly decreases after 40 years.
Convergence: Necessary for proper ocular alignment and depth perception during close work.

Spectacle and Contact Lens Requirements

Prescription for spectacles may differ from contact lenses; contact lenses typically require adjustment of diopters by -0.25 to -0.5 compared to glasses.
Regulations stipulate wearing corrective lenses during flight, with a requirement for a spare pair.

Limitations and Medical Flight Tests

Visual limitations (e.g., VDL, VNL, VML) govern standards for aviation duties based on corrective measures and visual acuity.
Medical flight tests evaluate the ability to handle aircraft controls in normal and emergency conditions, ensuring safety during operation.

Comprehensive Eye Examination Steps

Includes history taking, visual acuity assessments (near, intermediate, distant), external eye examination, and fundoscopy for underlying conditions.
Regular examinations are mandated if there is any noticeable decrease in vision or upon the occurrence of eye-related issues.

Amblyopia and Monocular Requirements

Amblyopia, a developmental condition resulting in poor vision in one eye, necessitates specific standards of visual acuity for pilots.
Monocular pilots must have a better eye vision corrected or uncorrected > 1.0, with normal visual fields.

Key Takeaways for AME

Understanding and effectively applying visual examination protocols and standards is vital for certifying pilots.
Awareness of various visual requirements and limitations is essential to ensure pilots meet safety regulations while operating aircraft.

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Description

This quiz covers the essential aspects of the visual system, including the anatomy of the eye, refraction, visual acuity assessment, and color vision testing methods. Explore various techniques used in ophthalmological examinations and the importance of standardizing tests. Delve into visual aids and the implications for certification and medical flight tests.