general Flashcards
3 requirement for stereopsis
- large binocular overlap of VF
- partial decussation of afferent viisual fibres
- co-ordinated conjugate eye movement
4 types of stereotest
r-g - TNO
CYLINDER GRATING - LANG
polarised - butterfly/ randot test
real thickness - frisby
all steorotest uses randot
AGE GROUP selection for stereotest
2-3 - lang and frisby
>3 randot, tno, butterfly, titmus fly
what are the test for colours
colours made easy
ishihara
what are the ways to gather response for C Made Easy
point, trace, name
what are the va test available for infant - 18m
7 test
Differential objective occlusion
prefential looking - teller, lea paddle, keeler
fixate and follow
100 and 1000s
screening test for young children and retards
visual evoke potential
OKN
what are the test chart to choose for preverbal, verbal, preiliterate, illiterate
pre v - cardiff
v - kay picture
pre i - sheridan gardiner
i - snellen/ logmar
what are the va test available for 18m -36m
7 test:
cardiff acuity
kay picture
keeler logmar
broken wheels
computerized optotype
sheridan gardiner
lea symbol card
ssx of reduce vx in infant - toddler
8 ssx:
- no ssx
- rub eyes
- lack of interest in small item
- clumsiness
- inattentiveness
- poor tracking
- unable to recognized familiar faces
ssx of reduce va in preschool - school age
7 ssx:
- no ssx
- avoid near work
- poor athletic
- shy
- headaches
- squinting / brow ache
- hold book close
how to we select occlusion method?
via age:
birth to 3: sticker patch
3-7: eye patch, paed trial frame
7- 10: handheld occluder, eyepatch, trial frame and occluder lens
>10: occluder, trial frame and occlusion lens
paediatric va test selection overview by age
- birth to 6 months
- 6m to 18m
3.18 -36m - > 3
- birth to 6 months
- DOO
- PL
- Fixate and follow
- OKN - 6m to 18m
- DOO
- PL
- 100 and 1000s
3.18 -36m
- sheridan gardiner
- Cardiff acuity
- kay picture
- lea symbol
- keeler logmar
- broken wheel
- computer optotype
- > 3
- sheridan gardiner
- logmar
- snellen (illiterate E, landolt C)
what is the refractive norms for premature babies
- short al , shallow ac, highly curved cornea
- premature eyes developed less hypermetropia due to diff in ACD and cornea curvature
- high prevalence of myopia
- myopia decrease as child goes
*all compare against full term
FT babies refractive norms
- low to moderate hyperopia decreasing with age
- low to moderate astig decreasing over 1st year
ssx of uncorrected rx in young children
- poor stereopsis - difficult with depth perception, and eye hand coordination difficulties
- frequent rub eye
- blink excessively
- cannot maintain fixation on task
- frequently close/ cover 1 eye
- lack of interest in out door activities
- lack of interest in near task
- squinting
- no ssx
ssx of myopia based on age :
1. birth - 5 yo
2. >5
- birth - 5 yo
- low rx - no ssx
- moderate to high - lack of interest at distance object, get close to toys, books/ tv - > 5
- hold book close
- squint to see the board
- fail vx screening
- poor va at all distance
ssx of hyperopia based on age :
1. birth - 5 yo
2. >5
- birth - 5 yo
low rx: no ssx
mod to high: possible esotropia, lack of interest in near task, poor eye hand coordination and perceptual skills - > 5
low - no ssx
mod: lack of interest in near task, poor reading skills, asthenopia
high : reduced va at dist and near
ssx of astigmatism based on age :
1. birth - 3yo
2. 3-5 yo
3. >5
- birth - 3yo
- no ssx - 3-5 yo
- reduced va, decrease interest in fine detailed task - > 5
- reduced distance at distanec and near
- asthenopia
ssx of anisometropia based on age:
1. birth to 4
2. >4
- birth to 4
- possible no ssx
- decreased stereopsis/ other bv skills
-amblyopia - > 4
- asthenopia
- decreased stereopsis/ other bv skills
-amblyopia
rx changes during school years (>5) and their possible outcome
> 1.50D - tend to remain hyperopic
+0.50 - +1.25 - tend to become emmetreopic
pl to +0.50 - tend to be myopic
<pl - tend to be more myopic
why should refraction be conducted before bv assessment
ensure, clear retinal image, and balance correction in both eye
*also impt as accommodative esotropia can be corrected with spx
what are the types of refraction test we can use for paeds
6 test:
- mohindra
- distance retinoscopy
- cycloplegic refraction
the following test are only taken as screening/ confirmation:
- photorefraction
- autorefractor
- k meter and keratoscope
what are the indication for cyclopegic refraction
8 indication:
- fluctuating reflexes
- inability to fixate
- uncooperative
- strabismus
- suspected latent hyperopia
- amblyopia
- anisometropia
- high accom lag
how do we control accommodation in children
- interesting target
- fixate at 6m
- use wdl for older children
- neutralise and push for max plus
- cycloplegic if indicated - best way
what is the selection of refraction test based on age
<3 - near retinoscopy, cycloplegic refraction
3-5: distance, cycloplegic, subjective rx
types of cycloplegia available
3 types:
- atropine - hospital esp for esotropic
- cyloplegic spray -useful for uncooperative and light iris
- cyclopentolate 1% - hospital 2 drops, 5 mins after, refraction 30 mins after
