A comparison between amblyopic and fellow eyes in unilateral amblyopia using spectral-domain optical coherence tomography

Ocular blood flow evaluation by laser speckle flowgraphy in pediatric patients with anisometropia

Purpose

To determine the differences and reproducibility of blood flow among hyperopic anisometropic, fellow, and control eyes.

Methods

We retrospectively studied 38 eyes of 19 patients with hyperopic anisometropia (8.2 ± 3.0 years of age) and 13 eyes of eight control patients (6.8 ± 1.9 years). We measured the optic nerve head (ONH) and choroidal circulation using laser speckle flowgraphy (LSFG) and analyzed the choroidal mean blur rate (MBR-choroid), MBR-A (mean of all values in ONH), MBR-V (vessel mean), MBR-T (tissue mean), and sample size (sample), which are thought to reflect the ONH area ratio, area ratio of the blood stream (ARBS). We then assessed the coefficient of variation (COV) and intraclass correlation coefficient (ICC) and compared the differences among amblyopic, fellow, and control eyes in MBR, sample, and ARBS.

Results

The ONH, MBR-A, MBR-T, and ARBS of amblyopic eyes were significantly higher than those of fellow eyes (P < 0.01, P < 0.05, and P < 0.05, respectively), and control eyes (MBR-A and ARBS, P < 0.05, for both comparisons). The sample-T (size of tissue component) in amblyopic eyes was significantly smaller than that in fellow and control eyes (P < 0.05). Blood flow in the choroid did not differ significantly between the eyes. The COVs of the MBR, sample, and ARBS were all ≤10%. All ICCs were ≥0.7. The COVs of pulse waveform parameter fluctuation, blowout score (BOS), blowout time (BOT), and resistivity index (RI) in the ONH and choroid were ≤10%.

Conclusion

The MBR value of the LSFG in children exhibited reproducibility. Thus, this method can be used in clinical studies. The MBR values of the ONH in amblyopic eyes were significantly high. It has been suggested that measuring ONH blood flow using LSFG could detect the anisometropic amblyopic eyes.

Morphological changes of the retinal layers in the central macula in children with anisometropic amblyopia

PURPOSE

The goal of this study was to evaluate the morphological characteristics of the retinal layers in the central macula in children with anisometropic amblyopia.

METHODS

This comparative, observational, prospective study included 28 patients who were diagnosed with anisometropic amblyopia and 30 age- and sex-matched healthy controls. All children were evaluated using the automatic calculation software system available on spectral-domain optical coherence tomography (SD-OCT) for automated segmentation of the macula.

RESULTS

Of the included patients, 18 (64.3%) were male and 10 (35.7%) were female, with a mean age of 10.3±3.4 years. Mean spherical equivalent and best-corrected visual acuity (BCVA) were 4.13±1.95 diopters and 0.707±0.36 logMAR, respectively. The mean axial length was significantly lower in amblyopic eyes compared to fellow eyes (22.1±0.34mm vs. 23.3±0.42mm, P<0.0001), and control eyes (22.1±0.34mm vs. 23.1±0.40mm, P<0.0001). The mean thickness of the outer nuclear layer was significantly lower in amblyopic eyes compared to fellow eyes (79.8±11.9μm vs. 86.8±7.9μm, P=0.007), and healthy controls (79.8±11.9μm vs. 87.4±10.5μm, P=0.012).

CONCLUSION

The results of this study showed that there are quantitative differences in retinal microstructures of the macula in eyes with anisometropic amblyopia compared to fellow eyes and healthy controls. These findings suggest that anisometropic amblyopia may result in abnormal development of macular structure in the inner retinal layer. A detailed analysis of retinal layers may be able to provide a guide to the depth of amblyopia and visual prognosis.

[Role of optical coherence tomography in unilateral amblyopia]

PURPOSE

To compare the macular and papillary parameters on optical coherence tomography (OCT) between the amblyopic eye and the healthy eye in subjects with unilateral strabismic or anisometropic amblyopia.

PATIENTS AND METHODS

This is a cross-sectional and comparative study carried out over two years, from April 1, 2019, to March 31, 2021. We included patients aged over 5years, followed for unilateral amblyopia, free of any neurological and/or ocular pathology. The evaluation of the macular and papillary parameters in the amblyopic and healthy eyes was performed with Swept-Source Optical Coherence Tomography (OCT-SS). The parameters were compared according to age group and type of amblyopia.

RESULTS

We collected 50 patients, 29 children, and 21 adults, with a mean age of 19.8years. Amblyopia was secondary to anisometropia in 40 patients and strabismus in 10 patients. Analysis of macular tomographic parameters found no significant difference between amblyopic eyes and healthy eyes for mean macular thickness (P=0.86), central macular thickness (P=0.86), or mean macular volume (P=0.54). The mean retinal peripapillary fiber thickness (RNFL) was 107.48μm in the amblyopic eye and 103.8μm in the healthy eye, with a statistically significant difference (P<0.001). This significant thickening of the RNFL in amblyopic eyes was present in adults (P<0.001), children (P<0.001), anisometropic (P<0.001), and strabismic amblyopia (P=0.024). Analysis of the other optic nerve head parameters revealed no significant difference between amblyopic eyes and healthy eyes in terms of optic disc surface area (P=0.89), neuro-retinal annulus surface area (P=0.47), vertical (P=0.98) or horizontal (P=0.74) cup to disc ratio.

CONCLUSION

Amblyopia is accompanied by thickening of the peripapillary retinal fibers without macular repercussions. However, larger prospective studies are needed to confirm these results.

Morphological changes in amblyopic eyes in choriocapillaris and Sattler's layer in comparison to healthy eyes, and in retinal nerve fiber layer in comparison to fellow eyes through quantification of mean reflectivity: A pilot study

Purpose

Establishing the reliability of a new method to check the mean retinal and choroidal reflectivity and using it to find retinal and choroid changes in amblyopia.

Methods

Design: Retrospective case-control. Population: 28 subjects of which 10 were healthy controls (20 eyes): 8 with refractive errors, 1 with strabismus, and 1 with both. 18 patients with unilateral amblyopia included: 7 anisometropic, 6 isoametropic, 1 strabismic, and 4 combined. Mean participants’ age: 13.77 years ± 10.28. Observation procedures: SD-OCT and ImageJ. Main outcome measure: mean reflectivity of retinal and choroid layers. Amblyopic, fellow, and healthy eyes were compared.

Results

The method of measuring reflectivity is good to excellent reliability for all regions of interest except the fourth. The mean reflectivity of the choriocapillaris and Sattler’s layer in amblyopic eyes were significantly lower than in healthy eyes (p = 0.003 and p = 0.008 respectively). The RNFL reflectivity was lower than that of fellow eyes (p = 0.025). Post-hoc pairwise comparisons showed statistically significant differences between amblyopic and healthy eyes for choriocapillaris (p = 0.018) and Sattler’s (p = 0.035), and between amblyopic and fellow eyes for RNFL (p = 0.039).

Conclusion

A decrease in reflectivity of the choriocapillaris and Sattler’s in amblyopic compared to healthy eyes, and a decrease in reflectivity of the RNFL in the amblyopic compared to fellow eyes, indicate that the pathophysiology is partly peripheral and might be bilateral.

Evaluation of macular and optic nerve head parameters in amblyopic eyes: An optical coherence tomography study

PURPOSE

To evaluate morphological differences in retinal nerve fibers layers (RNFL), optic nerve head (ONH), ganglion cell complex (GCC), and macular thickness between amblyopic and normal eyes from spectral domain optical coherence tomography (SD-OCT).

METHODS

Of 234 eyes of 117 children, four groups emerged: group A (162 eyes of 81 non-amblyopic subjects); group B (32 fellow eyes of 32 subjects with monolateral amblyopia); group C (32 amblyopic eyes of 32 subjects affected by monolateral amblyopia); group D (8 amblyopic eyes of 4 subjects with bilateral amblyopia). Patients underwent SD-OCT for ONH parameters, RNFL, GCC and macular thickness, retina map, and ONH scan quality index (SQI). Two-sided p values <0.05 were taken as statistically significant. (Analysis: STATA v.13).

RESULTS

Parameters with a significant difference between groups (p < 0.005) with their Standard Deviation (SD) are presented: rim area, 2.08 (0.49) mm² in group A and 1.76 (0.68) mm² in group C; disk area, 2.43 (0.45) mm² in group A and 2.02 (0.71) mm² in group C; central macular thickness, 250.99 (19.74) µm in group A and 267.16 (23.52) µm in group C; nerve fiber ONH SQI, 62.82 (13.15) in group A, 51.26 (15.55) in group C, 48.29 (14.37) in group D; retina map SQI, 63.34 (10.34) in group A and 57.34 (9.84) in group C. For other parameters no significant difference was observed (p > 0.005).

CONCLUSIONS

Amblyopia may influence optic nerve morphology, central macular thickness, and OCT scan quality. RNFL and GCC are not affected by monolateral amblyopia.

Macular Thickness Profile and Its Association With Best-Corrected Visual Acuity in Healthy Young Adults

Purpose

To describe the thickness profiles of the full retinal and outer retinal layers (ORL) at the macula in healthy young adults, and associations with best-corrected visual acuity (BCVA).

Methods

In total, 1604 participants (19-30 years) underwent an eye examination that included measurements of their BCVA, axial length, and autorefraction. The retinal thickness at the foveal pit and at the nine Early Treatment of Diabetic Retinopathy Study macular regions (0.5-mm radius around the fovea, and superior, inferior, temporal, and nasal quadrants of the inner and outer rings of the macula) were obtained using spectral-domain optical coherence tomography imaging. A custom program was used to correct for transverse magnification effects because of different axial lengths.

Results

The median full retinal and ORL thicknesses at the central macula were 285 µm and 92 µm. The full retina was thinnest centrally and thickest at the inner macula ring, whereas the ORL was thickest centrally and gradually decreased in thickness with increasing eccentricity. There was no association between axial length and the full retinal or ORL thickness. Increased thicknesses of the full retina at the central macula was associated with better BCVA; however, the effect size was small and not clinically significant.

Conclusions

This article mapped the full retinal and ORL thickness profile in a population-based sample of young healthy adults.

Translational Relevance

Thickness values presented in this article could be used as a normative reference for future studies on young adults and in clinical practice.

Neonatal sleep development and early learning in infants with prenatal opioid exposure

The aim of this chapter is to examine the role of sleep and cognition in the context of the cumulative risk model examining samples of at-risk infants and maternal-infant dyads. The cumulative risk model posits that non-optimal developmental outcomes are the result of multiple factors in a child's life including, but not limited to, prenatal teratogenic exposures, premature birth, family socioeconomic status, parenting style and cognitions as well as the focus of this volume, sleep. We highlight poor neonatal sleep as both an outcome of perinatal risk as well as a risk factor to developing attentional and cognitive capabilities during early childhood. Outcomes associated with and contributing to poor sleep and cognition during infancy are examined in relation to other known risks in our clinical population. Implications of this research and recommendations for interventions for this population are provided.

Impact of Amblyopia on the Central Nervous System

Amblyopia is a common perceptual disorder resulting from abnormal visual input during development. The clinical presentation and visual deficits associated with amblyopia are well characterized. Less is known however, about amblyopia's impact on the central nervous system (CNS). While early insights into the neuropathophysiology of amblyopia have been based on findings from animal models and postmortem human studies, recent advances in noninvasive magnetic resonance imaging (MRI) techniques have enabled the study of amblyopia's effects in vivo. We review recent retinal and neuroimaging research documenting amblyopia's structural and functional impact on the CNS. Clinical imaging provides some evidence for retinal and optic nerve abnormalities in amblyopic eyes, although the overall picture remains inconclusive. Neuroimaging studies report clearer changes in both structure and function of the visual pathways. In the optic nerves, optic tracts, and optic radiations of individuals with amblyopia, white-matter integrity is decreased. In the lateral geniculate nuclei, gray matter volume is decreased and neural activity is reduced. Reduced responses are also seen in the amblyopic primary visual cortex and extrastriate areas. Overall, amblyopia impacts structure and function at multiple sites along the visual processing hierarchy. Moreover, there is some evidence that amblyopia's impact on the CNS depends on its etiology, with different patterns of results for strabismic and anisometropic amblyopia. To clarify the impact of amblyopia on the CNS, simultaneous collection of retinal, neural, and perceptual measures should be employed. Such an approach will help (1) distinguish cause and effect of amblyopic impairments, (2) separate the impact of amblyopia from other superimposed conditions, and (3) identify the importance of amblyopic etiology to specific neural and perceptual deficits.

Evaluation of Bruch's membrane opening-minimum rim width and retinal nerve fiber layer thickness in adults with anisometropic amblyopia

PURPOSE

To investigate the relationship between Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT) in adult patients anisometropic amblyopia using spectral domain optical coherence tomography (SD-OCT).

MATERIALS AND METHODS

In this cross-sectional, observational study, 43 anisometropic eyes with corresponding fellow eyes. BMO-MRW (shortest distance from BMO to the internal limiting membrane) and peripapillary RNFLT were obtained with Spectral Domain Optic Coherence Topography (SD-OCT). Global and six sectors values according to the legacy distribution of the SD-OCT (nasal [N], nasal superior [NS], temporal superior [TS], temporal [T], temporal inferior [TI], and nasal inferior [NI]) for both RNFLT and BMO-MRW were evaluated.

RESULTS

Mean RNFLT and BMO-MRW measurements comparison showed no significance between anisometropia and fellow eyes. In correlation analyses ; although all sectors showed significant positive correlations; the global, TS and NI BMO-MRW sectors were significantly correlated with their corresponding RNFLT within both anisometropia and fellow eyes. In subgroup caparison analyses RNFLT and BMO-MRW showed no differences between amblyopia and fellow eyes. On subgroups correlation analyses, there were not a consistent correlation sectors between RNFLT and BMO-MRW.

CONCLUSIONS

In the analysis of the BMO-MRW and RNFLT measurements obtained by SD-OCT in adult anisometropic amblyopia patients, both parameters were evaluated not significant on showing structural changes. In correlation analysis within amblyopic and fellow eye groups, while there was positive correlation on all sectors, statistically significant relationships were detected in global, NI, TS sectors for both BMO-MRW and RNFLT measurements.

Inter-Ocular Symmetry of Vascular Density and Retinal Thickness in Unilateral Anisometropic Amblyopia

Background

Inter-ocular symmetry of macular vascular anatomy in healthy subjects has been well documented in previous optical coherence tomography angiography (OCTA) studies. In our present study, we have demonstrated that the presence of anisometropic amblyopia in one eye does not alter this unique feature significantly. We investigated whether the presence of unilateral anisometropic amblyopia due to moderate amounts of hyperopia and/or astigmatism would have any significant influence on measurements of retinal thickness (RT) and superficial vessel density (SVD) in adult subjects.

Subjects and methods

In the study group, both eyes of 21 adult subjects with unilateral anisometropic amblyopia were enrolled. Only one eye of an age-matched control group including 33 subjects was randomly selected. RT and SVD were measured in foveal and parafoveal retinal areas and compared in amblyopic eyes, their fellow eyes and in the control group. Inter-ocular symmetry of RT and SVD in amblyopic and fellow eyes were investigated by using correlation analysis.

Results

There were statistically significant inter-ocular correlations of foveal and parafoveal RT in amblyopic and fellow eyes (P < 0.0001, for both). Foveal and parafoveal RT of the control group were not statistically different from amblyopic eyes (P = 0.072 and P = 0.46, respectively). There was no difference between foveal SVD of amblyopic eyes and control group (P = 0.10) and a significant inter-ocular correlation was found between amblyopic and fellow eyes (P = 0.029).

Conclusion

For our adult subjects, none of the investigated OCTA parameters of the amblyopic eyes were found to be statistically different from those of age-matched controls. The preservation of inter-ocular symmetry in the amblyopic and fellow eyes implies that the influence of anisometropic amblyopia in one eye would be relatively small and negligible on routine OCTA examination.

Changes in macular ultrastructural morphology in unilateral anisometropic amblyopia

It is controversial that retina and photoreceptors are involved in amblyopic development. Lack of imaging devices for quantitative assessment of photoreceptors in vivo impedes further investigation. In this study we investigated the differences of macular thickness, outer nuclear layer (ONL) thickness and cone density among eyes with unilateral anisometropic amblyopia, amblyopic fellow eyes, and normal control eyes using high-definition spectral-domain optical coherence tomography and adaptive optics imaging system. Thicker fovea and parafovea with characteristic quantitative retinal changes in unilateral amblyopic patients indicated that the amblyopic process might involve the retina. Cones tended to be homogeneously distributed at 1.5° from the foveal center in all participants. However, we did not detect any significant differences in cone density and ONL thickness at 1.5° from the foveal center in patients with unilateral amblyopia when compared with the fellow eyes and the normal control eyes. This is the first study to explore whether photoreceptors are involved in amblyopic development in vivo that would help for understanding the underlying mechanisms of amblyopia. Whether macular changes relate to cone photoreceptors migration of the amblyopic eyes remains to be determined.

Quantitative analysis of retinal microcirculation in children with hyperopic anisometropic amblyopia: an optical coherence tomography angiography study

PURPOSE

To evaluate optical coherence tomographic angiography (OCTA) findings on retinal microcirculation in hyperopic anisometropic amblyopia compared with fellow eyes and nonamblyopic control eyes.

METHODS

A total of 40 pediatric patients with hyperopic anisometropic amblyopia and 57 control subjects were recruited, and 137 eyes (40 amblyopic, 40 fellow, and 57 control eyes) were evaluated. Data on best-corrected visual acuity (logMAR), axial length (mm), refractive error, and OCTA findings (foveal avascular zone parameters, macular vascular density in superficial and deep retinal capillary plexus, central macular thickness) were recorded in amblyopic, fellow, and control eyes.

RESULTS

Compared with fellow and control eyes, amblyopic eyes were associated with significantly lower foveal vessel density values within 300 μm around the foveal avascular zone (P < 0.01) and lower vascular density in certain areas of superficial and deep retinal capillary plexus in axial length- and refraction-adjusted analysis (P < 0.05 for all), along with significantly higher full thickness of the central macula (P = 0.04). In amblyopic eyes, best-corrected visual acuity values were negatively correlated with foveal density (r = -0.57; P = 0.02) and deep capillary retinal plexus vascular density in foveal (r = -0.51; P = 0.03) parafovea temporal (r = -0.52; P = 0.03), and parafovea superior (r = -0.51; P = 0.04) areas.

CONCLUSIONS

Our findings indicate a possible association between retinal microcirculation and amblyopia.

CAN Optical Coherence Tomography redefine amblyopia?

Introduction: For many years, amblyopia was regarded as a disorder of the visual system in which an organic cause could not be identified. Optical Coherence Tomography opens new horizons in understanding the etiopathology of amblyopia and seems to highlight morphologic anomalies in the retina of the amblyopic eye.

Purpose: The objective of this paper is to analyze the macular thickness, optic nerve changes, and choroidal thickness found in patients diagnosed with amblyopia based on trials reported in the literature.

Material and methods: This study analyzes 30 clinical trials regarding amblyopia evaluation with Optical Coherence Tomography. The research articles analyzed were published between 2006 - 2016 and were identified on PubMed database.

Results: 19 research studies focused on macular and nerve optic changes, 7 on choroidal changes and 6 on retinal changes after occlusion. The results were discussed according to the type of amblyopia, alteration of macular thickness, optic nerve changes, ganglion cell layer changes, and alteration of choroidal thickness.

Conclusions: The results are of great variability, and it seems that macula and choroid involvement is more frequently suggested compared with optic nerve involvement.

Abbreviations: OCT = Optical Coherence Tomography, RNFL = Retinal Nerve Fiber Layer, GCC = Ganglion Cell Complex, ACD = Anterior Chamber Depth, BCVA = Best Corrected Visual Acuity

Macular retinal and choroidal thickness in unilateral amblyopia using swept-source optical coherence tomography

Background

To investigate macular retinal and choroidal thickness in amblyopic eyes compared to that in fellow and normal eyes using swept-source optical coherence tomography (SS-OCT).

Methods

This study examined 31 patients with hyperopic anisometropic amblyopia (6.9 ± 3.8 years, mean ± standard deviation), 15 patients with strabismic amblyopia without anisometropia (7.9 ± 4.2 years), and 24 age-matched controls (7.8 ± 3.3 years). Retinal and choroidal thickness was measured by 3D scans using SS-OCT. A 6-mm area around the fovea was automatically analyzed using the Early Treatment Diabetic Retinopathy Study map. The thickness from SS-OCT was corrected for magnification error using individual axial length, spherical refraction, cylinder refraction, and corneal radius. Retinal thickness was divided into the macular retinal nerve fiber layer (mRNFL), ganglion cell layer + inner plexiform layer (GCL+IPL), ganglion cell complex (GCC), and the inner limiting membrane to the retinal pigment epithelium (ILM-RPE) thickness. Retinal and choroidal thickness was compared among amblyopic, fellow, and normal eyes.

Results

In both amblyopia groups, there was no significant difference in the mRNFL, GCL+IPL, and GCC thicknesses among the amblyopic, fellow, and control eyes. In the anisometropic amblyopia group, choroidal thickness (subfovea, center 1 mm, nasal and inferior of the inner ring, nasal of the outer ring, and center 6 mm) of amblyopic eyes were significantly greater than that of fellow and normal eyes. In contrast, none of the choroidal thicknesses were significantly different among the investigated eyes in the strabismic amblyopia group.

Conclusions

We found no significant difference in inner retinal thickness in patients with unilateral amblyopia. Although there were significant differences in choroidal thickness with hyperopic anisometropic amblyopia, there was no significant difference for the strabismic amblyopia. The discrepancy in choroidal thickness between the two types of amblyopia may be due to both differences in ocular size and underlying mechanism.

Changes in macular parameters in different types of amblyopia: optical coherence tomography study

PURPOSE

The purposes of this study were to investigate the changes in macular parameters (thickness, volume) and peripapillary retinal nerve fiber layer (RNFL) thickness (RNFLT) in different cases of amblyopia versus the normal fellow eyes using optical coherence tomography (OCT) and to estimate the relationship of OCT changes with various defined patients' parameters.

DESIGN

This is a prospective, observational, cross-sectional case series.

METHODS

The method involved measuring the peripapillary RNFLT, macular thickness, and macular volume via spectral domain (OCT) in different types of amblyopia and comparing with the other fellow eyes. This study was conducted at the Mansoura Ophthalmic Center.

RESULTS

A total of 64 patients with different types of amblyopia were included. The mean central macular thickness (CMT) was 196.2±50.03 µm in the amblyopic eyes versus 167±12.76 µm in the fellow eyes (P=0.000), the mean average macular thickness was 265.80±12.77 µm in the amblyopic eyes versus 259.10±3.09 µm in the fellow eyes (P=0.000), the mean macular volume was 7.59±0.32 mm³ in the amblyopic eyes versus 7.34±0.071 mm³ in the fellow eyes (P=0.002), and the mean global RNFLT was 97.00±11.60 µm in the amblyopic eyes versus 78.50±13.05 µm in the fellow eyes (P=0.029). There was a discrepancy between the different amblyopic types. Age and the axial length were the only independent variables that statistically significantly correlated with the CMT.

CONCLUSION

The unilateral amblyopic eyes were prone to have a higher CMT and thicker global RNFL compared to those of the sound fellow eyes. Retinal variations between different types of the amblyopia differ from one type to another. The age could be considered as a predictor of the disease worsening and treatment prognosis. Further studies are required to emphasize these results.

Retinal Nerve Fibre Layer and Macular Thicknesses in Adults with Hyperopic Anisometropic Amblyopia

Objectives. This study compared the macular and retinal nerve fibre layer (RNFL) thicknesses and optic nerves of eyes with reduced vision due to anisometropia with the contralateral healthy eyes in adults using optical coherence tomography (OCT). Methods. This cross-sectional study was conducted in Atatürk State Hospital, Sinop, Turkey. Macular and RNFL thicknesses, optic nerve disc area, cup area, and horizontal and vertical cup-to-disc ratios obtained using a NIDEK RS-3000 SLO spectral domain OCT device were compared between the amblyopic and fellow eyes in 30 adults with anisometropic amblyopia 18–55 years old who were seen in our clinic with unilateral poor vision. Results. The mean macular thickness was 266.90 ± 23.22 µm in the amblyopic eyes and 263.90 ± 22.84 µm in the fellow eyes, and the mean RNFL thickness was 111.90 ± 12.9 and 109.70 ± 9.42 µm, respectively. The two thicknesses did not differ significantly between the amblyopic and fellow eyes. There were also no significant differences between the eyes in disc area, cup area, and horizontal-vertical cup/disc ratios. Conclusion. There does not seem to be a difference in macular thickness, peripapillary RNFL, or optic disc structures between the amblyopic and fellow eyes in adults.