OPT505 Lecture 14: Routine Refraction Basics

NUT-FREE ZONE

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LECTURE RECORDING

• The lecture is being recorded.
• The recording will be available on the module DLE pages.
• Students can comment or ask questions.
• Questions may appear on the recording.
• Participants can ask to pause recording if they do not want their questions to be included.

OPT505 LECTURE 14: BUILDING A ROUTINE REFRACTION

• The lecture is about building a routine refraction.
• The lecturer is Ellie Livings.

INTENDED LEARNING OUTCOMES

• Understand 'basic routine'.
• Monocular v binocular refraction.
• Binocular balancing.
• Latent hyperopia.

PRINCIPLES OF EYE EXAMINATION OR SIGHT TEST

• Internal and external examinations are required.
• Additional tests are necessary to detect injury or disease.
• The same optometrist should conduct the entire episode of care, unless transferred.
• Responsible optometrist interprets findings.
• Automated instruments, such as visual field analyzers, are part of examination.

KEY POINTS

• There is a suggested equipment list (Annex 1).
• All clinical findings must be recorded.
• Sufficient time must be allowed for the examination.
• The format and content of the examination are based on professional judgement and legal requirements.
• An 'episode of care' in the context of eye exam encompasses the entire care journey from initial testing to final prescription.

BASIC MINIMUM ROUTINE

• Introduction (Intro), health & safety (H&S), prelims.
• Objective refraction.
• Subjective refraction.
• Supplementary tests.
• Health assessment.
• Record management.
• Time estimate per section in minutes.

PROCEDURE FOR MONOCULAR REFRACTION

• Follow red arrows.
• Retinoscopy using occlusion of one eye, followed by un-occlusion.
• Refraction of each eye, including best vision spherical (BVS) and cylinder (x-cyl) measurements.
• Refine spherical values.
• Obtain VA values for each eye.
• Plus 1 blur.
• Un-occlude and Balance both eyes.
• Binocular Add (+0.25DS).

BINOCULAR CONSIDERATIONS

• Most people have binocular vision.
• Accommodation balance between eyes is needed.
• Accommodation is not independent, eyes need to accommodate together.
• Unbalanced accommodation can lead to asthenopia.

WHAT'S THE PROBLEM WITH OCCLUSION?

• Occlusion can dilate the pupil and result in refractive changes from spherical aberration.
• Occlusion can mask latent nystagmus and make subjective refraction difficult.
• Incorrect assessment of astigmatism could result from occlusion.
• Occlusion stimulates accommodation.

ACCOUNTING FOR ACCOMODATION AND BINOCULARITY

• Refraction can be completed separately monocularly, or as a combined binocular process.
• Blurry vision of one eye when refactoring leads to suppression of central vision but peripheral fusion is maintained for binocularity.

PLUS 1 BLUR

• Shows visual acuity (VA) when one eye is blurred by 1 diopter (plus 1).
• Diagram shows visual acuity for each eye on a scale.

ACCOMMODATIVE BALANCE

• Diagram with measurement scales indicating accommodation for each eye.

MONOCULAR V BINOCULAR REFRACTION

• Separated monocular refraction process for each eye.
• Combined binocular refraction process encompassing both eyes.
• Monocular subjective approach required when binocular accommodation is not a concern.

SUBJECTIVE REFRACTION

• Monocular subjective testing method for people with poor binocular vision.
• Binocular subjective method for people with normal binocular vision.
• Pros and cons of each type of subjective testing.

WHO GETS BINOCULAR BALANCING/REFRACTION?

• People with monocular vision.
• People with deep amblyopia.
• People with strabismus.
• People with very poor VA in one eye.

TECHNIQUE 1: MONOCULAR SUBJECTIVE + BINOCULAR BALANCE

• Monocular refraction (RE/LE).
• Binocular balancing.
• Binocular add.
• Record final Rx with final VA values.
• Retinoscopy steps for each eye.

MONOCULAR SUBJECTIVE + BINOCULAR BALANCE: OPTIONS

• Multiple refracting techniques to measure binocular balance.
• Techniques for cases with or without fusional vergence present.

RELAXING ACCOMMODATION EQUALLY IN BOTH EYES

• Methods such as Modified Humphriss, Humphriss Immediate Contrast, and Prism Dissociated Balance for better binocular accomodation.

MODIFIED HUMPHRISS

• Steps to accurately determine appropriate lens power for patient.
• Instructions on what to ask the patient.

CASE SCENARIOS

• Case studies providing specifics such as patient age, eye condition, and retinoscopy results to indicate the need for monocular or binocular refraction.

CYCLOPLEGIC COMPARISON

• Table comparing different cycloplegic drugs based on dose, maximum cycloplegia time, duration of action, tonus allowance, and residual accommodation.

DEALING WITH LATENT HYPEROPIA

• Strategies to manage latent hyperopia focusing on subjective and binocular refraction, prescribing adjustments, monitoring cover tests, and patient communication.

CYCLO

• Issues to consider with unstable ret reflex testing.
• When binocular issues are suspected.
• History of amblyopia/high plus.
• Unequal vision/VA without refractive causes.

WHAT DROPS?

• Cycloplegic eye drops are available to temporarily paralyze the ciliary muscles.
• Description of different drops, including effects, duration and recovery time.

PRESCRIBING POST-CYCLO

• Instructions for referring patients appropriately and measuring visual acuity pre and post procedure, reducing prescription as required, and communicating with parents.

BACKGROUND LEARNING

• Suggested activities for review prior to attending the session on these topics. (Reading specific lab book sections, reviewing Moodle resources, studying and preparing for the full routine procedure, reviewing health, safety, prelims, and management).

This quiz covers the essential principles of routine refraction as discussed in OPT505 Lecture 14 by Ellie Livings. You'll explore fundamental concepts such as monocular and binocular refraction, balancing techniques, and the importance of thorough eye examinations. Test your knowledge on key learning outcomes and critical practices in optometry.