Refraction Instruments Overview
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Questions and Answers

What is the primary function of ophthalmic lenses?

  • To correct focal points hitting the retina (correct)
  • To provide protection from UV light
  • To improve night vision
  • To enhance color perception

What does the Worth Four Light Test assess?

  • Visual acuity only
  • Stereoscopic vision
  • Color blindness
  • Binocular vision, including anomalies (correct)

Which description best fits low vision aids?

  • Equipment designed solely for nocturnal use
  • Devices for enhancing color perception
  • Tools for improving visual performance in low vision individuals (correct)
  • Only used for children with complete blindness

How do prisms function in combination with ophthalmic lenses?

<p>By correcting or relieving eye deviations (B)</p> Signup and view all the answers

What is the main purpose of stereoscopic devices?

<p>To enhance three-dimensional perception (B)</p> Signup and view all the answers

What is the primary purpose of a slit lamp during an eye examination?

<p>To evaluate the eye from external to internal (A), To test the binocularity of the eye (C)</p> Signup and view all the answers

Which instrument is specifically designed to measure the angle of a squint?

<p>Amblyoscope (B)</p> Signup and view all the answers

What does the prism cover test primarily measure?

<p>Ocular alignment (B)</p> Signup and view all the answers

Which of the following types of contact lenses is NOT commonly recognized?

<p>Adjustable contact lens (B)</p> Signup and view all the answers

How do prism bars assist in monitoring ocular alignment?

<p>By calculating correction needed in surgery (A)</p> Signup and view all the answers

Which device is primarily used to aid individuals with low vision?

<p>Magnifiers (B)</p> Signup and view all the answers

What is the significance of assessing the degree of misalignment in eyes?

<p>To monitor recovery from muscle imbalance (D)</p> Signup and view all the answers

Which instrument is not typically associated with the examination of binocularity?

<p>Optical coherence tomography (D)</p> Signup and view all the answers

What is the primary purpose of a visual acuity chart?

<p>To determine the smallest letters a person can read (A)</p> Signup and view all the answers

What is the function of a perimeter in ocular health examination?

<p>It measures peripheral vision (C)</p> Signup and view all the answers

Which instrument is primarily used to observe the back of the eyeball?

<p>Ophthalmoscope (C)</p> Signup and view all the answers

What does failing a color vision test indicate?

<p>Potential color blindness or deficiency (D)</p> Signup and view all the answers

Which of the following describes what the slit-lamp is used for?

<p>To examine the structural details of the eye (A)</p> Signup and view all the answers

What does the ETDRS stand for in the context of eye examinations?

<p>Early Treatment Diabetic Retinopathy Study (B)</p> Signup and view all the answers

What type of lenses does a spherical concave lens belong to?

<p>Concave lenses (C)</p> Signup and view all the answers

What is the purpose of a keratometer?

<p>To measure the anterior corneal curvature (D)</p> Signup and view all the answers

When testing visual acuity, what is the standard distance used?

<p>20 feet (6 meters) (A)</p> Signup and view all the answers

Which instrument is used to objectively measure the refractive error of the eye?

<p>Retinoscope (D)</p> Signup and view all the answers

What function does a phoropter serve in optometry?

<p>It contains various lenses to assess refractive error (C)</p> Signup and view all the answers

How does an auto-refractor differ from traditional refraction techniques?

<p>It automates the assessment of refraction (B)</p> Signup and view all the answers

Which statement best describes the function of a lensmeter?

<p>It verifies the prescription of eyeglasses (D)</p> Signup and view all the answers

What is trial lens and frame used for in optometry?

<p>To perform refraction tests (D)</p> Signup and view all the answers

Which instrument is specifically designed to assess astigmatism?

<p>Keratometer (B)</p> Signup and view all the answers

What is the primary function of a retinoscope in optometry?

<p>To shine light into the eye for refractive error assessment (B)</p> Signup and view all the answers

Flashcards

Keratometer

An instrument that measures the curvature of the cornea.

Retinoscope

A handheld instrument that shines light into the eye to measure refractive error.

Phoropter

Instrument with lenses/prisms evaluating eye's refractive error.

Trial Lens & Frame

Set of lenses for determining eyeglass prescriptions during refraction.

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Auto-Refractor

Instrument that automatically assesses eye's refraction.

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Lensmeter

Instrument used to check/verify eyeglass prescription.

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VA Chart/Optotypes

Used to measure visual acuity.

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Refraction

Process of determining eyeglass prescription.

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Spherical Concave Lens

A type of lens that curves inward, causing light rays to diverge (spread out).

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Spherical Convex Lens

A type of lens that curves outward, causing light rays to converge (come together).

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Cylindrical Lens

A lens with one curved surface and one flat surface, used to correct astigmatism.

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Loose Prism

A piece of glass with a triangular shape that bends light.

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Visual Acuity Chart

A chart used to determine how well someone can see at a distance.

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Ophthalmoscope

A handheld instrument with a light and lenses used to view the back of the eye.

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Slit Lamp

A microscope-like instrument with a bright light and a slit, used to examine the eye's structures.

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Visual Field Test

A test that measures how far you can see to the sides and above/below while looking straight ahead.

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Ophthalmic Lenses

Medical devices that correct vision problems by adjusting the focal point to hit the retina.

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Worth-4-Dot Test

A simple test to assess binocular vision, including double vision (diplopia), eye dominance, and how the eyes work together.

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Contact Lenses

Thin, clear plastic disks worn on the eye to improve vision. They act as an extension of the eyeball.

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Stereoscopic Devices

Tools used to assess depth perception, the ability to see objects in three dimensions.

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Prisms (Ophthalmic)

Thin lenses that can be added to eyeglasses to correct or reduce eye misalignment.

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Binocular Vision

The ability of both eyes to work together to create a single, three-dimensional image.

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Amblyoscope

An instrument used to measure the degree of eye misalignment (squint) and assess how well both eyes work together.

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Prism Bars

Used in eye exams to measure the alignment of the eyes and determine the amount of correction needed for strabismus (misalignment).

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Single Vision Lens

An eyeglass lens that provides a single focus for distance or near vision.

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Double Vision Lens

An eyeglass lens that combines two focal points for both distance and near vision.

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Hard Contact Lens

A rigid, gas-permeable contact lens that provides a clear, sharp vision.

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Soft Contact Lens

A flexible, comfortable contact lens made from soft materials.

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Study Notes

Refraction Instruments

  • Keratometer/Ophthalmometer: Measures anterior corneal curvature, astigmatism axis, and extent. The process is called keratometry.

  • Retinoscope: Handheld instrument shining light into the eye. Objectively measures refractive error.

  • Trial Lens & Frame: Set of spherical concave, spherical convex, cylindrical lenses, and prisms, used during refraction.

  • Phoropter: Instrument with cylinders, prisms, and lenses to measure eye's refractive error and determine eye prescription. All trial lenses mounted in one instrument.

  • Auto-Refractor/Optometer: Instrument assessing refraction automatically. Alternative to conventional methods.

  • Lensmeter/Lensometer: Instrument used to verify eyeglasses/spectacle prescription. Determines lens power.

  • VA Chart/Optotypes: Chart used to determine smallest visible letters. Standardized charts (Snellen charts) used at 20 feet (6 meters) or special charts for shorter distances.

Other Instruments

  • Ophthalmoscope: Small flashlight-sized instrument to view the back of the eyeball. Features light and lenses.

  • Slit Lamp: Microscope with bright light used during eye exams, focusing light into the eye to observe and evaluate.

  • Visual Field Instruments (Perimeter): Measures peripheral vision.

  • Color Vision Devices: Measures ability to differentiate colors. May be used to detect colorblindness.

  • Binocular Vision Examination Instruments: Tests binocularity, including amblyoscope, prism bars, Worth 4-dot, and stereoscopic devices. Assess if eyes work together.

  • Amblyoscope: Measures squint angle and assesses degree to which a person uses both eyes together.

  • Prism Bars: Used for measures ocular alignment, calculating correction amounts in strabismus surgery, and monitoring muscle imbalances.

  • Worth-4-Dot Test (W4LT): Clinical test for binocular vision. Assesses diplopia, suppression, and anomalous retinal correspondence.

Ophthalmic Appliances & Devices

  • Ophthalmic Lenses: Single vision, double vision, contact lenses (hard, soft, RGP), prisms (measuring, relieving, dissociating, adverse).

  • Low Vision Aids: Improve visual performance in low vision, enabling academic and social adaptation. (Magnifiers, Telescopic Aids, ocular exercises)

  • Contact Lenses: Thin, clear plastic disks worn in the eye to improve vision. (Soft, RGP, Scleral)

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Related Documents

OPTO101 Unit 4: Instruments in Optometric Practice PDF

Description

Explore the various instruments used in refraction, such as keratometers, retinoscopes, and phoropters. This quiz will test your understanding of their functions and uses in measuring eye refractive errors. Perfect for those studying optometry or ocular science.

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