OCT in Amblyopia

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OCT in Amblyopia

• Lionel Kowal

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OCT in Amblyopia

• Hypothesis
• Amblyopia _at_ least partly reversible poor
  vision 2 to abnormal visual devpt in a
  morphologically normal eye
• Majority reverse with appropriate treatment
• Treatment failures may have a subtle anatomical
  anomaly that can account for the lack of success

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OCT in Amblyopia

• Aims
• Using Optical Coherence Tomography (OCT) to
  assess the anatomy of amblyopic eyes and compare
  the anatomical measurements in those with visual
  improvement and those without visual improvement
  after appropriate amblyopic treatment.

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OCT in Amblyopia

• Hypothesis
• Patients with presumed amblyopia where vision
  does not improve with appropriate treatment have
  anatomical anomalies such as foveal or optic
  nerve hypoplasia that is not detected by standard
  examination.

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OCT in Amblyopia

• Methods
• Children who can do the test gt4 years old
• BCVA 6/24 or worse in the amblyopic eye
• No explanation detected by usual examination

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OCT in Amblyopia

• Methods
• OCT to measure macular thickness
• Scan accepted if the following apply
• Centration reflection is central
• Centre of scan is blue
• Signal strength of 4 or above
• SD of macular thickness less than 10 OR clearly
  difference between thicknesses clearly exceeds SD
• Macular thickness of those with BCVA improved
  after amblyopia treatment compared with those who
  didnt

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OCT in Amblyopia

• Results Analysis by Dr E Wong

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Thicknesses of the fovea and retinal nerve fiber
layer in amblyopic and normal eyes in children

• Korean J Ophthalmol. 2006 20(3)177-81. Kee SY,
  
• OCT on 26 children (52 eyes) with unilateral
  amblyopia that was due to anisometropia or
  strabismus on 42 normal children (84 eyes),
  for a total of 136 eyes.

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Thicknesses of the fovea and retinal nerve fiber
layer in amblyopic and normal eyes in children

• Average age normal children 8.5Y, amblyopia 8y
• Retinal thickness measurements from fovea, and
  NFL thickness measurements from superior,
  inferior, nasal and temporal quadrants in the
  peripapillary region.
• The average thickness of the fovea was 157.4 in
  normal eyes and was 158.8 in amblyopic eyes (p
  0.551).
• The thicknesses of the superior, inferior, nasal
  and temporal quadrants of the retinal nerve fiber
  layer between the normal cf amblyopia children
  not statistically significant

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Thicknesses of the fovea and retinal nerve fiber
layer in amblyopic and normal eyes in children

• Children with anisometropic cf strabismic
  amblyopia, the average thicknesses of the fovea
  were 146.5 and 173.1, respectively, and the
  retinal nerve fiber layer thicknesses were
  measured to be 112.9 and 92.8, respectively, and
  these were statistically significant differences
  (p 0.046, 0.034, respectively).

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Thickness of the retinal nerve fiber layer,
macular thickness, and macular volume in patients
with strabismic amblyopia

• J Pediatr Ophthalmol Strabismus. 2005 Jul-Aug
  42(4)216-21. Altintas O, . Turkey.
• OCT on 14 pts with unilateral strabismic
  amblyopia aged 5-18 y
• The RNFL thickness average analysis program was
  used to evaluate mean superior, inferior,
  temporal, and nasal thickness. The data for all
  clock quadrants (12 values averaged) the
  overall RNFL.
• The retinal thickness and volume analysis program
  was used to evaluate macular scans.

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Thickness of the retinal nerve fiber layer,
macular thickness, and macular volume in patients
with strabismic amblyopia

• RESULTS The mean age (/- SD) was 10.4y (/-
  4y).
• Mean visual acuity of 0.3 (/- 5.70).
• OCT parameters including the RNFL thickness in
  all quadrants, overall RNFL thickness, macular
  thickness, and macular volume showed no
  significant differences between the two groups

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WHY ARE THESE RESULTS SO DIFFERENT TO MINE?

• Its the fish that John West rejects. Im very
  careful to exclude technically imperfect /
  suspect scans THE MAJORITY!
• Difficult technique
• Eccentric fixation a difficult confounder
• ..wait for Cirrus

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OCT in Amblyopia

• Conclusions
• There may be structural macular changes in some
  cases of amblyopia
• May be a prognostic indicator for amblyopia
  treatment
• Further studies required .