Constant esotropia Flashcards
what is a primary constant esotropia
the esotropia is the initial defect and is present under all conditions
what are the two types of primary constant esotropia
- constant esotropia
with a accomodative element
without accomodative element
what is constant esotropia with a accomodative element
onset 1-3 years
the accomodative element may be
refractive- uncorrected hypermetropia - cant see things close to them
esotropia increases on accomodation without glasses
esotropia decreases with hypermetropic perscription but not eliminated
what are the reasons for a constant esotropia with a accomodative element
due to high aca ratio - esotropia for near is more than 10 diopters greater than for distance
esotropia reduces for near with +3 diopters (relax accomodation) but no eliminated
a combination of refractive and high aca ratio
a large deviaiton for near persists after refractive correction but reduces with +3.00ds
note - a high hypermetropia can decrease the esotropia by a significant amount in the presence of a normal ac/a ration and may not have an abnormal accomodative element
what are the types of constant esotropia with a accomodative element
acquired non accomodative esotropia
acquired esotropia with myopia
describe acquired non accomodative esotropia
early onset
early onset
onset 6 months - 2 years
amblyopia common
poor prognosis for restoring bsv
deviation may increase with time
often require surgery
what are the two types of acquired non accomodative esotropia
early onset (6 months)
and
late onset normo sensorial/ acute- onset concomitant esotropia)
describe constant esotropia w a accomodative element
late onset
late onset
onset = 2-8 years
may be caused by minor injury/ short occlusion of 1 eye
onset may be intermittent causing constant and large deviation
signs- closure of 1 eye/ dipolopia
good prognosis for restoring bsv
describe how esotropia can cause myopia
a type of constant esotropia without a accomodative element
esotropia with myopia
moderate degree -6 to 12ds
gradual onset and present in young adults
esotropia is greater for distance
signs - c/o diplopia
require prism/ surgical management
describe how a high degree of myopia can cause a constant esotropia without a accomodative element
- esotropia with myopia
high degree (- 15DS)
Very gradual onset
often 1st present in adult life
associated with progressive myopia (elongation of the globe)
sings rarely c/o diplopia
restricted ocular motlility llimitation of abduction (due to a enlarged glove compressing the lateral rectus
describe the indicidence of esotropia
esotropia is more common than exotropia in childhood
prevalance of esotropia in school children= 0.3% —— 3.6%
incidence of esotropia 111 per 100.000 people < 19 years
what are risk factors for esotropia
low birth weight < 3000 gram
prevelance of strabismus 12-36%
normal paediatric populaition 0.1 to 6%
premature birth before 37 gestational weeks
large head circumfrence
children with chromosomal abnormalities or syndromes
describe the genetic correlations found for esotropia
primary esotropia
linkage to chromosone 7, locus stbmsi
this locus only accounts for a proportion of cases
what tests would you conduct to confirm the presence of a constant left esotropia
- va
- ct
asess potential for bsv- convergence, bg/wl, synoptophore , sterotest
pct
fundus and media check
refraction under clycloplegia
what other tests would you perfrom to decide upon managment
asess fixation
investigation of suppression
density and area
further investigation of potential for bsv and establish maximum angle of deviation before surgery
prism adaptation test
how would you asess suppression
sbisa bar
repeat at each visit when treating amblyopia
area
prisms or synoptophore
post opperative dipolopia test
indentify risk of dipolopia after surgery or bt injection
what is the post ooperative diplopia test
used in patients with no demonstrable potential for bsv
need to be old enough for subjective testing
method
use prisms in free space near and distance with glasses
aim
under and over correct the angle of deviaiton up to 20 diopters
asess risk of moving image out of suppression scotoma and causing intractable diplopia
record prism at which diplopia appreciated or graphic pethod
what are the managment options for patients with a primary esotropia with and without a accomoative element
obtain optimum or equal va
restore normal bsv if possible
maintain ac if present
improve ocular alignement if no potential for bsv
what is the prism adaptation test
pat - asess potential for bsv
determine max angle of deviation before surgical correction
aim to fully correct or slightly over correct
who is it suitable for
children from the age of 3 years
require equal/ near equal va
va of 0.300logMAR (6/12) or better
angle of deviation less than or equal to 40 diopters
no vertical deviation
how would you perform the prism adaptation test
measure the size of deviation for near and distance
fully or slightly over correct deviaiton for distance with fresnel
- split diopteers between two eyes
if deviaiton is greater for near by diopters or more than the near angle should be corrected
measure size of deviaiton again to ensure fully corrected before send patient home
explanation
- explain reasons for the PAT
emphasise the importance of full time wear of glasses with prisms
review in 1-2 weeks to reasess potential for bsv and measure size of deviation
what are the 2 responses you can have a to a prism adaptation test
responders
bsv response - maybe microtropia
aim of surgery - correct max angle measured
non responders
no bsv
aim of surgery - correct original angle measured
what is the outcome of managment for patients with a primary constant esotropia
the age of onset is an important factor for restoring bsv following surgery
et without an accomodative element
- onest - less than 30 months - unlikely to develop steropsis following ocular aligment
onset - more than 44 moths and no amblyopia - more likely to devlop a good level of steroacuity
et with a accomodative element
onset- more than 36 months- more likely to develop good level of stereopsis
what are the management options for patients with no poitential for bsv
small deviaiton - no pychoscial issue
treat any amblyopia
observe until approc 7-8 years and no risk of amblyopia
treatment to improve ocular alignment - aim
make deviaiton less noticeable
slightly under correct angle by approx 10 diopters
perfrom post op diplopia test in all patients older than 7 years
what are potential management options
botulinum toxin injection
patients with a high risk of post op diplopia / unsuitable for surgery
controversial in young children - require repeat injections
surgery - unilateral medial rectus recession/lr resection - deviation approximatley equal near and distance
bilateral mediul rectus recession is the deviaiton is greater for near
how does surgery differ for small to moderate angles
surgery for small to moderate angles (15-35) perform 1 muscle operation
unliateral medial recession
large angle - 50- 70 diopters perform 2 muscle operation
bilateral medial rectus recession
medial rectus recession/ LR resection
greater than or equal to 70
perform 3 muscle operation
bilateral medial rectus recession/ lr resection
refractive surgery to correct hypermetropia
limited litretaure and long term data
kirwan et al al no real change in pre-op angle with glasses and pre- op
adovocated in adults
