Axial Length–Disc Area Ratio in Esotropic Amblyopia

Lempert, Philip

doi:10.1001/archopht.121.6.821

Cited by 26 publications

(23 citation statements)

References 14 publications

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“…Although most studies state the single cause and effect relationship noted above, several laboratory and clinical studies have made additional observations beyond the standard explanation (Almeder et al, 1990; Barrett et al, 2005; Lempert, 2000, 2003, 2004, 2008b; Lempert and Porter, 1998). In one instance the question has been cast as an interesting case of “which came first, the chicken or egg?” (Fielder and Moseley, 1996).…”

Section: Cause and Effect: A Classic Chicken And Egg Storymentioning

confidence: 99%

“…However, definitive evidence that anisometropia universally precedes development of the amblyopia is lacking, and the simplicity of this cause and effect relationship continues to be challenged (Almeder et al, 1990; Barrett et al, 2005; Lempert, 2000, 2003, 2004, 2008a, 2008b; Lempert and Porter, 1998, Smith and Hung, 1999). In light of the general uncertainty about the aetiology of anisometropia and anisometropic amblyopia, an examination of the literature is timely as part of the continuing effort to refine approaches to vision screening and clinical care.…”

Section: Introduction and Rationalementioning

confidence: 99%

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The relationship between anisometropia and amblyopia

Barrett

Bradley

Candy

2013

Progress in Retinal and Eye Research

144

121

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This review aims to disentangle cause and effect in the relationship between anisometropia and amblyopia. Specifically, we examine the literature for evidence to support different possible developmental sequences that could ultimately lead to the presentation of both conditions. The prevalence of anisometropia is around 20% for an inter-ocular difference of 0.5D or greater in spherical equivalent refraction, falling to 2-3%, for an inter-ocular difference of 3D or above. Anisometropia prevalence is relatively high in the weeks following birth, in the teenage years coinciding with the onset of myopia and, most notably, in older adults starting after the onset of presbyopia. It has about one-third the prevalence of bilateral refractive errors of the same magnitude. Importantly, the prevalence of anisometropia is higher in highly ametropic groups, suggesting that emmetropization failures underlying ametropia and anisometropia may be similar. Amblyopia is present in 1-3% of humans and around one-half to two-thirds of amblyopes have anisometropia either alone or in combination with strabismus. The frequent co-existence of amblyopia and anisometropia at a child’s first clinical examination promotes the belief that the anisometropia has caused the amblyopia, as has been demonstrated in animal models of the condition. In reviewing the human and monkey literature however it is clear that there are additional paths beyond this classic hypothesis to the co-occurrence of anisometropia and amblyopia. For example, after amblyopia secondary to either deprivation or strabismus has emerged, anisometropia often follows. In cases of anisometropia with no apparent deprivation or strabismus, questions remain about the failure of the emmetropization mechanism that routinely eliminates infantile anisometropia. Also, the chronology of amblyopia development is poorly documented in cases of ‘pure’ anisometropic amblyopia. Although indirect, the therapeutic impact of refractive correction on anisometropic amblyopia provides strong support for the hypothesis that the anisometropia caused the amblyopia. Direct evidence for the aetiology of anisometropic amblyopia will require longitudinal tracking of at-risk infants, which poses numerous methodological challenges. However, if we are to prevent this condition, we must understand the factors that cause it to develop.

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Section: Cause and Effect: A Classic Chicken And Egg Storymentioning

confidence: 99%

Section: Introduction and Rationalementioning

confidence: 99%

The relationship between anisometropia and amblyopia

Barrett

Bradley

Candy

2013

Progress in Retinal and Eye Research

144

121

View full text Add to dashboard Cite

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“…They concluded that unilateral amblyopia was associated with bilaterality, but also with subclinically hypoplastic ONs, greater than normal AL/ ON, and abnormal noncircular globe cross-section. Lempert [4,19] studied photographs of the ONs of human eyes with amblyopia and found that the optic disks of hypermetropic eyes with strabismus (with and without amblyopia) were disproportionately small in size compared with hypermetropic eyes without amblyopia or esotropia. He speculated that vision impairment in amblyopia is associated with ON hypoplasia with relative microphthalmos.…”

Section: Discussionmentioning

confidence: 99%

The effect of anisometropic amblyopia on retrobulbar blood flow parameters

Yılmaz

Güler²,

Türkçüoğlu³

et al. 2012

Int Ophthalmol

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To look for a correlation between or the effect of anisometropia amblyopia on retrobulbar blood flow parameters. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and temporal posterior ciliary artery (tPCA) were measured with color Doppler imaging, and systolic/diastolic ratio, resistivity index (RI), and pulsatility index (PI) were computed in 42 patients with anisometropic amblyopia. The mean PSV of OA, CRA, and tPCA in amblyopic and fellow eyes were 62.69 ± 24.04, 62.64 ± 20.18; 9.28 ± 3.71, 10.27 ± 4.18; 10.81 ± 4.59, 11.28 ± 4.91, respectively. The mean EDV of OA, CRA, and tPCA in amblyopic and fellow eyes were 15.87 ± 11.31, 14.52 ± 6.54; 2.48 ± 1.17, 2.62 ± 2.06; 3.04 ± 2.34, 3.14 ± 2.18, respectively. The mean RI of OA, CRA, and tPCA in amblyopic and fellow eyes were 0.76 ± 0.08, 0.76 ± 0.08; 0.72 ± 0.08, 0.74 ± 0.95; 0.72 ± 0.09, 0.72 ± 0.08, respectively. The mean PI of OA, CRA, and tPCA in amblyopic and fellow eyes were 1.77 ± 0.42, 1.81 ± 0.46; 01.58 ± 0.42, 1.59 ± 0.43; 1.54 ± 0.43, 1.58 ± 0.49, respectively. There was no statistically significant difference in any of the measured parameters between the amblyopic and fellow eyes. Anisometropic amblyopia did not cause any change in retrobulbar blood flow in amblyopic eyes.

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“…In special, esotropia is the most common cause of strabis mic and combined (strabismic and anisometropic) amblyopia (6,7) . Previous studies reported that esotropic amblyopic eyes are shorter than their fellow eyes (8,9) . Although most researchers agree that refractive error is in large part genetically determined, a growing body of evidence shows that visual experiences early in life may influence ocular growth and eventual refractive status (10) .…”

Section: Introductionmentioning

confidence: 91%

“…Eyes with amblyopia represent a group in which there is an abnormal visual input and this could be associated with impaired modulation of axial growth. Most previous investigations on amblyopic eyes (8,9,11) concentrated solely on the total axial length, not on the contribution of each ocular component to the total axial length. Only one study evaluated the contribution of anterior chamber depth, lens thickness and vitreous chamber depth as percentages of axial length in strabismic amblyopes.…”

Section: Biometric Relationships Of Ocular Components In Esotropic Ammentioning

confidence: 99%

Biometric relationships of ocular components in esotropic amblyopia

Debert¹,

Polati

Jesus

et al. 2012

Arq. Bras. Oftalmol.

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Purpose: To investigate the contribution of the individual ocular components, i.e. anterior chamber depth, lens thickness and vitreous chamber depth, to total axial length in patients with esotropic amblyopia. Methods: The study population consisted of 74 children, aged between 5 and 8 years: thirty-seven patients with esotropic amblyopia and 37 healthy volunteers (control group). The participants underwent a comprehensive ophthalmological examina tion, including cycloplegic refraction and A-scan ultrasonography. Anterior chamber depth, lens thickness, vitreous chamber depth and total axial length were recorded. Paired Student's t-tests were used to compare biometric measurements between amblyopic eyes and their fellow eyes and between right and left eyes in the control group. To evaluate the contribution of the ocular components to the total axial length, we report the individual components as a percentage of total axial length. Results:The comparison between amblyopic and fellow eyes regarding the individual contribution from ocular components to the total axial length revealed greater contribution from lens thickness (P=0.001) and smaller contribution from vitreous chamber depth (P=0.001) in amblyopic eyes, despite similar contribution from anterior chamber depth (P=0.434). The comparison between right and left eyes in the control group showed similar contributions from anterior chamber depth (P=0.620), lens thickness (P=0.721), and vitreous chamber depth (P=0.483). Conclusions: This study shows differences between amblyopic and non-amblyopic eyes when the total axial length is broken down into the individual contribution from the ocular components.

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Axial Length–Disc Area Ratio in Esotropic Amblyopia

Cited by 26 publications

References 14 publications

The relationship between anisometropia and amblyopia

The relationship between anisometropia and amblyopia

The effect of anisometropic amblyopia on retrobulbar blood flow parameters

Biometric relationships of ocular components in esotropic amblyopia

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