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Ophthalmology
The Preliminary Examination and Assessment of Visual Acuity
Built from Strabismus Simplified, Second Edition
What’s inside
9 sections · 110 slides
Overview
- Scope of the preliminary examination
History
- Value of the history in strabismus
- Common presenting complaints
- Uniocular versus binocular asthenopia
- Symptoms of recent onset squint
- Weighing the cosmetic complaint
- Age of onset and duration as prognostic factors
- Precipitating, antenatal and perinatal factors
- Characterising the deviation on history
- Head posture and old photographs
- Treatment history to be elicited
Refraction
- Cycloplegic refraction before any measurement
- Atropine cycloplegia protocol
- Atropine safety and parental counselling
- Sedation and prescribing under cycloplegia
- Interval between glasses and measuring deviation
- Emmetropisation and the schedule for repeat refraction
Anterior and posterior segment examination
- Anterior segment and pupillary examination
- Fundus findings that precede occlusion therapy
- Sites of fixation
- Eccentric fixation on the fundus
- Prognostic value of the fixation pattern
- Bilateral eccentric fixation
- Fundus torsion: the normal landmark
- Intorsion and extorsion on the fundus
- Torsional assessment on the fundus
Visual acuity: principles and charts
- Standard distance acuity testing in adults
- Snellen distance acuity chart
- LogMAR charts for academic and research use
- LogMAR acuity chart
- Organic basis of visual acuity
- Angular subtense of the Snellen optotype
- Optotype construction and crowding surrounds
- Types of visual acuity
- Detection acuity tests
- Recognition acuity tests: direction identification
- Recognition acuity tests: letters and pictures
- Resolution acuity tests
- Limitations shared by detection and resolution tests
- Estimating acuity from object size and distance
Vision testing in infancy
- Catford drum test
- Catford drum
- Reliability of the Catford drum
- Related drum tests
- Preferential looking tests
- Personnel required for the original preferential looking system
- Teller acuity cards: the card set
- Cycles, octaves and half octave steps
- Teller acuity card screen and grating aperture
- Contrast and illumination requirements for Teller cards
- Teller acuity card testing in progress
- Conversion of cycles per centimetre to Snellen equivalents
- Conversion of cycles per centimetre to Snellen equivalents (continued)
- Testing distance by age for Teller acuity cards
- Indications and drawbacks of Teller acuity cards
- Teller card acuity in normals compared with amblyopes
- OKNOVIS
- Cardiff acuity cards
- Visually evoked response: principle and stimulus
- Interpreting the P-100 and the two recording modes
- Reliability and value of VER estimates
- Sweep-VEP
- Reflex responses as indirect evidence of vision
- Development of fixation
- Fixation pattern and the visual acuity it implies
- Age of children and expected visual acuity
- Behavioural signs accompanying visual attention
- Fixation preference and resentment of occlusion
- Fixation preference test
- Induced prism test
- Follow movements
- Two phases of visual development
- Factors in maturation of vision
- Functions correlating with visual maturation
- Visual milestones by age
- Visual milestones by age (continued)
Age-appropriate vision tests
- Vision tests at 1 to 2 years
- Vision tests at 2 to 3 years
- Tumbling E test
- Tumbling E optotypes
- Crowding phenomenon and single letter acuity
- Landolt's C, Sheridan and HOTV letter tests
Hyperacuity and stereoacuity
- Hyperacuity
- Vernier acuity testing
- Gratings and Vernier gratings
- Stereoacuity in infancy and preschool screening
- Principles of clinical stereotests
- Tests using no dissociating glasses
- Randot stereotest
- TNO test
- Frisby stereotest
- Distance stereopsis testing
- Frisby Davis distance test
- Distance Randot test
- Normal stereoacuity values
- Gross stereopsis: the two-pencil test
- Two-pencil test for gross stereopsis
Summary
- Key points: history and refraction
- Key points: examination and acuity
- Key points: paediatric testing and stereopsis
- References
- Strabismus Simplified