6 Diagnostic Capability of Optical Coherence Tomography …
151
In 2011, Alotaibi et al. evaluated 93 unilateral amblyopic eyes (36 strabismic,
33 anisometropic, 24 combined) and found significantly thicker RNFL (259.3 vs.
255.6 µm, p < 0.0001) in the overall amblyopic group, and no significant difference
in macular and foveal thickness [172]. There was slightly higher macular and foveal
thickness only in the anisometropic amblyopic group (macular thickness: 256.76 vs.
246.61 µm p 0.050; foveal thickness: 187.12 vs. 177.61 µm p 0.039). However,
they did not measure the AL either [172].
In the studies by Dickmann et al. a significant difference between the amblyopic and the fellow eye was found in mean macular thickness only in the strabismic
amblyopic group, and there was no difference for the refractive amblyopic group,
similarly to the cpRNFL in any of the amblyopic groups [175, 176]. Alotaibi and
Dickmann suggested based on their findings that amblyopia of different etiologies is
associated with the loss of different neural cells [172, 175, 176]. Later, in 2012, Dickmann evaluated 15 strabismic (esotropic) and 15 anisometropic amblyopic patients,
and found no intereye differences in cpRNFL, macular thickness and foveal volume
in neither group using SD-OCT [180].
In 2011, Pang et al. investigated 31 myopic children with unilateral amblyopia [178]. The refractive error in spherical equivalent in the amblyopic eyes was
−10.79 ± 3.40 diopters and in the normal fellow eyes was −1.67 ± 2.90 D. The
mean magnitude of anisometropia was 9.12 ± 3.53 D, ranging from 3.63 to 17.50
D. They found a statistically significant difference in macular thickness between
amblyopic and fellow eyes, with amblyopic eyes having greater foveal thickness but
reduced inner and outer macular thickness [178]. No statistically significant differences were identified in the macular thicknesses between subgroups (purely myopic
anisometropia n 24, combined mechanism amblyopia n 7). IOD in AL (measured
AL with A-scan ultrasound biometry) showed a moderate correlation with the nasal,
superior and temporal outer macular thickness [178].
To the best of our knowledge, there are three recent studies that employed some
form of OCT image segmentation in amblyopia so far. Al-Haddad et al. used one
single horizontal SD-OCT scan for the manual segmentation of six layers of the
central 1000 µm diameter area and found an increase in the INL and a decrease
in the ONL in the temporal area in amblyopic eyes compared to the fellow eyes,
while the mean foveal thickness was increased in amblyopic eyes (228.56 ± 20.2
vs. 221.7 ± 15.3 µm) [191]. Tugcu et al. used the built-in analysis option of the
RTVue OCT platform to measure the thickness of the GCC and found an increase in
strabismic amblyopia (99.29 vs. 103.08 µm, p 0.019, amblyopic vs. nonamblopic
eye) while there was no such difference for the anisometropic or combined subgroups [171]. Park et al. enrolled 20 unilateral amblyopic children (16 strabismus, 2
anisoastigmatism, 2 unilateral ptosis) with a mean age of 9.0 ± 4.03 (4–19 years) and
examined horizontal and vertical SD-OCT scans through the fovea [182]. Thickness
values were measured at the foveal centre and in 500 and 1500 µm distance from the
foveal centre in all 4 quadrants (superior, inferior, nasal, temporal). The thickness of
each retinal layer (GCL+IPL, INL, OPL, ONL, IS, OS, RPE) was measured manually
using the callipers provided with the SD-OCT instrument. They found significantly
decreased thickness in the thickness of the GCL+IPL at all four nasal and temporal
151
In 2011, Alotaibi et al. evaluated 93 unilateral amblyopic eyes (36 strabismic,
33 anisometropic, 24 combined) and found significantly thicker RNFL (259.3 vs.
255.6 µm, p < 0.0001) in the overall amblyopic group, and no significant difference
in macular and foveal thickness [172]. There was slightly higher macular and foveal
thickness only in the anisometropic amblyopic group (macular thickness: 256.76 vs.
246.61 µm p 0.050; foveal thickness: 187.12 vs. 177.61 µm p 0.039). However,
they did not measure the AL either [172].
In the studies by Dickmann et al. a significant difference between the amblyopic and the fellow eye was found in mean macular thickness only in the strabismic
amblyopic group, and there was no difference for the refractive amblyopic group,
similarly to the cpRNFL in any of the amblyopic groups [175, 176]. Alotaibi and
Dickmann suggested based on their findings that amblyopia of different etiologies is
associated with the loss of different neural cells [172, 175, 176]. Later, in 2012, Dickmann evaluated 15 strabismic (esotropic) and 15 anisometropic amblyopic patients,
and found no intereye differences in cpRNFL, macular thickness and foveal volume
in neither group using SD-OCT [180].
In 2011, Pang et al. investigated 31 myopic children with unilateral amblyopia [178]. The refractive error in spherical equivalent in the amblyopic eyes was
−10.79 ± 3.40 diopters and in the normal fellow eyes was −1.67 ± 2.90 D. The
mean magnitude of anisometropia was 9.12 ± 3.53 D, ranging from 3.63 to 17.50
D. They found a statistically significant difference in macular thickness between
amblyopic and fellow eyes, with amblyopic eyes having greater foveal thickness but
reduced inner and outer macular thickness [178]. No statistically significant differences were identified in the macular thicknesses between subgroups (purely myopic
anisometropia n 24, combined mechanism amblyopia n 7). IOD in AL (measured
AL with A-scan ultrasound biometry) showed a moderate correlation with the nasal,
superior and temporal outer macular thickness [178].
To the best of our knowledge, there are three recent studies that employed some
form of OCT image segmentation in amblyopia so far. Al-Haddad et al. used one
single horizontal SD-OCT scan for the manual segmentation of six layers of the
central 1000 µm diameter area and found an increase in the INL and a decrease
in the ONL in the temporal area in amblyopic eyes compared to the fellow eyes,
while the mean foveal thickness was increased in amblyopic eyes (228.56 ± 20.2
vs. 221.7 ± 15.3 µm) [191]. Tugcu et al. used the built-in analysis option of the
RTVue OCT platform to measure the thickness of the GCC and found an increase in
strabismic amblyopia (99.29 vs. 103.08 µm, p 0.019, amblyopic vs. nonamblopic
eye) while there was no such difference for the anisometropic or combined subgroups [171]. Park et al. enrolled 20 unilateral amblyopic children (16 strabismus, 2
anisoastigmatism, 2 unilateral ptosis) with a mean age of 9.0 ± 4.03 (4–19 years) and
examined horizontal and vertical SD-OCT scans through the fovea [182]. Thickness
values were measured at the foveal centre and in 500 and 1500 µm distance from the
foveal centre in all 4 quadrants (superior, inferior, nasal, temporal). The thickness of
each retinal layer (GCL+IPL, INL, OPL, ONL, IS, OS, RPE) was measured manually
using the callipers provided with the SD-OCT instrument. They found significantly
decreased thickness in the thickness of the GCL+IPL at all four nasal and temporal