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Vision Assessment and Vision Screening in Children, Refractive Error and Spectacle Correction, Amblyopia, Strabismus and Nystagmus
This document provides a comprehensive overview of vision assessment and screening in children, detailing various visual conditions such as refractive errors, amblyopia, strabismus, and nystagmus. It outlines age-specific visual milestones, assessment techniques, and corrective measures for different visual impairments. Additionally, it discusses the implications of these conditions on pediatric eye care and the importance of prompt diagnosis and treatment.
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Vision Assessment and Vision Screening in Children, Refractive Error and Spectacle Correction, Amblyopia, Strabismus and Nystagmus
- 1. Vision Assessment andVision Screening in Children Refractive error and spectacle correction Amblyopia Strabismus Nystagmus Rabindra Adhikary M. Optom 1st Batch Tilganga Institute of ophthalmology (TIO) Pokhara University Facilitators: Dr Srijana Adhikari, Dr Rojeeta Parajuli Date: 4th of June, 2019
- 2. Pediatric Ophthalmology – Layout •Vision Assessment and Vision Screening in Children • Refractive error and spectacle correction • Amblyopia • Strabismus • Nystagmus
- 3. Visual acuity • Preverbalchildren – Motor or sensory response to a threshold stimulus – Known size at a known distance • Pre-literate and verbal Children – Smallest target of known size at known distance correctly verbally identified by a child
- 4. Visual Milestones Age VisualBehavior 0-1 month Fixate &Turns eye and head to look at the light source / Looks high contrast object (mother’s hairline) + Horizontal Tracking At 1 month, fixation is central, steady and maintained 3 month Vertical and circular tracking Interested in mobiles Lip-reading / responsive smile 6 months Reaches towards, and later grasps the hanging objects Observes toys falling and rolling away 10 Looks for hidden toys Interested in pictures 1 year Recognize people 2 years Picture Matching 3 years Letter matching of single letters 5 years Snellen chart by matching or naming
- 5. Gross Estimate ofVA Age Snellen’s Equivalent Birth 6/120 4 months 6/60 6 months 6/36 1 year 6/18 2 years 6/6
- 6. Recognition Acuity • Smallestnumber, letter or other shapes that can be recognized –
- 7. Resolution Acuity • PreferentialLooking – Child prefers to look at the grating • Striped grating • Uniform filed – Forced choice preferential looking (FCPL) – 2 months to 1 year or pt with mental disabilities – Visual threshold=75% correct inferences • Drawbacks of PFL – Difficult to hold a child’s attention for long – Reliability is dependent on many trials – Near test
- 9. OKN • Drifting OKNgenerated by – Resolvable stimuli • Jerky Nystagmus – Pursuit (follows target) – Saccade (jumps to next)
- 10. VEP • Measures electricalactivity directly from the scalp through surface electrodes – Amplitude and timing of wave of electrical activity – Go on presenting finer and finer stimuli • Until zero response amplitude • Abnormal VEP? – Problem with the visual information reaching cortex
- 12. Age-wise VA assessment •Infants – PFL/OKN/VEP – Cat ford Drum • 1-2 years – STYCAR • For retards too – Boeck Candy test – Worth’s Ivory Ball test • 2-3 years – Miniature Toy test – Cardiff Acuity test – Coin test – Lea symbols • 3-5 years – Allen’s picture cards – Sheridan’s HOTVX letter test – Lippman’s HOTV Test • 5-6 years – Snellen
- 13. Screening • Age rangesand visual/ocular pathology to be detected by screening: Pre-term Perinatal/infantile Pre-school School age ROP Congenital cataract Glaucoma Anterior segment disorder Amblyogenic factors -anisometropia -strabismus -high refractive error -Ptosis -Media opacity Refractive error
- 14. Fixation Reflex • CSM –Monocular central fixation (C) • No eccentric fixation – Hold steady Fixation (S) – Maintain fixation (M) • With the viewing eye • Even when the fellow eye is uncovered • F + F – Fixate and Follow the light stimuli – Monocular viewing conditions
- 15. Pupillary Response • Birth-3 years (or upto when VA can’t be measured) • Pupil reactions to the changes of light stimulus – Direct – Consensual • Not equivalent to visual ability but indicates – Intact neurologic visual pathways
- 16. Red Light Reflex •Bruckner Test • 0-3 years • Ophthalmoscope – Position the light to illuminate BE • Reflex – Symmetrical – Equal intensity – Healthy red color
- 17. Corneal Light Reflex •Hirschberg’s test • 2 months- 8 years • Strabismus (D/Dx: pseudostrabismus) • Corneal reflection of Penlight – Positioned symmetrically on both pupils
- 18. Cover test • Toknow if eye deviates when fusion is interrupted – Observing the fixating eye when other eye is covered (Cover test) – Observing the eye being uncovered for movement when the occluder is shifted to the other eye (alternate cover) – Observing the eye being uncovered for movement when the occluder is removed (cover uncover)
- 19. Stereo-acuity • 3-8 years •Needs polarized glass • Random dot E or stereo butterfly • To check problems with stereo-acuity and depth perception
- 20. Color vision • At6 years (first grader) • Others: optional • To check color deficiency – Ishihara Pseudo-isochromatic Plates, – Color Vision Testing Made Easy – Good-Lite Book of Color Plates. • Fluorescent desk lamp - if enough natural daylight is not available.
- 21. Age vs RefractiveError General Trends Premature Infant High myopia ( ± ROP) Newborn (full term) baby Hyperopia ( 1-2 D) Toddler (preschool) Less hyperopia / low Myopia (towards Emmetopia) School Children Emmetropia or school myopia Adolescent Myopia
- 22. Refraction • Cycloplegic Refraction: –Greater range of accommodation – Fluctuating fixation – Pseudomyopia – Strabismus – High hyperopia / latent Hyperopia – Inconsistent results • Near Retinoscopy
- 23. Prescription • Should notinterfere with the emmetropization • Only if beyond normal range for that age
- 24. Hyperopia upto 1year • Isohyperopia – Error ≥ 2D & deviation present • Prescribe the full cyclopegic correction • Mandate frequent F/u if < 2 D – Prescribe partial (2/3rd) if ≥ 5D • Anisohyperopia – < 2.5 D (No Rx if no deviation) – ≥ 2.5 • Partial for no deviation • Full Rx if esodeviation
- 25. Myopia upto 1year • Isomyopia < -5 D – No Rx (Regular monitoring) • Isomypia ≥ 5 D – Rx with 1-2 D less • Aniso-mypia ≥ 2.5 D – Prescribe
- 26. Hyperopia in preschoolers (upto6 years) • Isohyperopia – Deviation present? Full Rx if error ≥ 1.5 D – No deviation? Partial Rx (2/3rd) if ≥ 2.5 D • Anisohyperopia – < 1.5 ( No Rx, R/w 3 months) – ≥1.5 D (partial for no deviation) • Full for esodeviation
- 27. Myopia in Preschoolers •Isomyopia < 3 – No Rx • Isomyopia ≥ 3 – Prescribe but undercorrection • Aniso-myopia ≥ 2D – Prescribe
- 28. School Age • AsymptomaticIsometropia ≥ 1.5 Prescribe – Near full correction (emmetropization ended) • Hyperopic anisometropia ≥ 1D – Full correction • Myopia? – Optimum correction is warranted
- 29. Aphakic Correction • Challenges –High plus – Astigmatism – No accommodation • Correction – Overcorrect by 2-3 D in first few months • Near consideration – Decrease the overcorrection to 1-2D ≈1 year • Intermediate distance consideration – Bifocals in school age • N+D consideration Lawrence formula for aphakic correction, P = +11 + half of pre-op error
- 30. Amblyopia • Visual impairmentwithout obvious organic ocular pathology – observer sees nothing and the patient very little (Albrecht von Graeffe) • Critical period – Visual development permanently disrupted if deprived of stimulation – Age of neural plasticity • Weeks of deprivation betn 3-6 months • Months of deprivation below 8 years
- 31. causes • Strabismus – Constantlydeviated eye amblyopic • Refractive error & anisometropia • Form deprivation – Cataract/ptosis/corneal opacity
- 32. Amblyopia • Most commoncause – Anisometropia (>1.5D) • Anisohyperopia is more amblyogenic than anisomyopia • Astigmatism – Can’t be overcome by accommodation • >1.5D is amblyogenic • >1 D (>10o from90/180) – Full cylinder correction recommended • Myopia ≥ 3D • Hyperopia ≥ 3.5
- 33. Strabismus • Constancy – Constantor intermittent • Laterality – Unilateral, alternate • Horizontal deviation – Exo or eso • Vertical deviation – Hypo or Hyper • Comitancy – Comitant or incomitant • Cause – Primary or secondary • Age of onset – Infantile or acquired
- 34. Esodeviation 1. Comitant Eso A.Accommodative • Refractive (normal AC/A) • Non-refractive (High AC/A) • Hypo-accommodative • Partially accommodative B. Non-accomodative • Infantile (birth to 6 months) • Acquired – Basic – Non accommodative convergence excess – Esotropia in Myopia – Acute esotropia – Divergence insuffieciency – Cyclic esotropia C. Microtropia D. Nystagmus Blockage Syndrome
- 35. 2. Incomitant Eso A.Paralytic B. Non paralytic or non-paretic i. A and V pattern ii. Retraction Syndromes iii. Mechanical restrictive esodeviation – Congenital fibrosis – Acquired-restrictive (trauma, myopathy, surgery, etc) 3. Secondary Eso A. Sensory B. Consecutive
- 36. Exotropia 1. Infantile Exo 2.Acquired Exo – Intermittent – Acute 3. Microexotropia 4. Secondary Exo – Sensory – Consecutive
- 37. Nystagmus • Involuntary, rhythmic,pendular or jerky conjugate oscillation – Congenital – Acquired
- 38. Congenital Manifest Nystagmus •First 3 months of life • Cause – Cataract – Congenital glaucoma – Aniridia – Achromatopsia – Down’s syndrome – High Myopia – Optic Nerve Hypoplasia – Leber’s amaurosis – OCA
- 39. Latent Vs Manifest-latent •Latent – Evoked by occluding one eye – Absence when both eyes are open • Manifest latent – Latent nystagmus that gets evident at some gazes – Is lesser in amplitude than the latent one • Ocular Nystagmus – Congenital (or with in 1st week ) ocular defects • Spasmus Nutans – 1st year of life and disappears 1-2 years – High Frequency (7Hz), small amplitude – Head nodding
- 40. • Sensory DefectNystagmus – Cause: inadequate image formation at fovea – Anterior visual pathway disease – Always B/L and horizontal – Pendular and oscillates with equal velocity in both direction • Motor Defect – Cause: efferent mechanism disruption – Centers or pathways for oculomotor pathways – Null Point: VA improved due to dampening of Nystagmus
- 41. M. Optom FirstBatch @TIO (2019)