Changes in choroidal blood flow and choroidal thickness after treatment in two cases of pediatric anisohypermetropic amblyopia

Influence of Aflibercept on Choroidal Blood Flow and Thickness in Branch Retinal Vein Occlusion: A Six-Month Follow-Up Study

BACKGROUND/OBJECTIVES

We intended to investigate choroidal blood flow (CBF) and choroidal thickness (CT) alternations in treatment-naive eyes with non-ischemic branch retinal vein occlusion (BRVO) following intravitreal aflibercept injection (IVA).

METHODS

Twenty eyes of 20 patients with treatment-naive non-ischemic BRVO, treated with IVA 1+ pro re nata, were included in this study. In the BRVO eyes, CBF and CT were measured in the occlusive region, subfovea, as well as the non-occlusive region, via laser speckle flowgraphy (LSFG) and enhanced depth-imaging optical coherence tomography over a 6-month follow-up period. CBF was analyzed via the mean blur rate using LSFG analysis software (version 3.10.0).

RESULTS

CT showed significant reductions in both the occlusive and subfoveal region at 1 week and 1 month after treatment (both p < 0.05). CBF was significantly decreased in the subfovea and the non-occlusive region at 1 week and 1 month from baseline, respectively (both p < 0.05). The mean number of IVA injections during the 6-month period was 1.95 ± 0.6.

CONCLUSIONS

Aflibercept treatment reduced CBF and CT in addition to a decrease in retinal thickness. These changes at each region might be associated with the improvement of macular edema in BRVO eyes.

Baseline Choroidal Blood Flow Imbalance as a Predictive Factor for Macular Edema Recurrence Secondary to Branch Retinal Vein Occlusion

BACKGROUND/OBJECTIVES

To evaluate the roles of choroidal blood flow (CBF) and choroidal thickness (CT) as predictors of macular edema recurrence in patients with treatment-naive non-ischemic branch retinal vein occlusion (BRVO) after intravitreal ranibizumab (IVR) injection.

METHODS

Sixteen eyes from sixteen patients with treatment-naive non-ischemic BRVO treated with IVR, once initially and then as needed, were included in the study. CBF and CT in the subfovea, occlusive, and non-occlusive regions were measured via laser speckle flowgraphy and enhanced depth imaging optical coherence tomography over 12 months.

RESULTS

Baseline CT was significantly greater in the occlusive region (335 ± 72.1 µm) than in the non-occlusive region (274 ± 36.7 µm, p = 0.028). CT in the occlusive region was reduced significantly after 1 week (p = 0.008), but CBF did not change significantly after IVR throughout the follow-up period (p > 0.05). The occlusive/non-occlusive region CBF ratio at baseline was significantly associated with the number of IVR injections over 12 months (mean 2.63) in patients with BRVO (p = 0.048).

CONCLUSIONS

Baseline CBF imbalance in eyes with treatment-naive BRVO may indicate the recurrence of macular edema after ranibizumab therapy.

Analysis of choroidal thickness, macular thickness, peripapillary retinal nerve fiber layer thickness, and macular vascular density in children with unilateral amblyopia using swept-source optical coherence tomography and their changes following occlusion therapy

PURPOSE

The purpose of this study was to analyze choroidal thickness (CT), along with macular thickness (MT), peripapillary retinal nerve fiber layer thickness (RNFLT), and macular vascular density (MVD) using swept-source optical coherence tomography (SS-OCT) in children with unilateral amblyopia, and compare the same with normal fellow eyes and normal eyes of normal children before and following occlusion therapy.

MATERIALS AND METHODS

This was a prospective, longitudinal study of 60 children (4-18 years); 30 children had unilateral amblyopia and remaining 30 were normal. Group 1 consisted of 30 amblyopic eyes of children with unilateral amblyopia; Group 2 consisted of 30 fellow normal eyes of Group 1; Group 3 consisted of normal eyes of normal children. Best-corrected visual acuity (BCVA) using logarithmic minimum angle of resolution (LogMAR) chart, detailed ophthalmic examination, SS-OCT for CT, MT, RNFLT, and MVD at the level of superficial, deep, and choriocapillary plexus in both eyes were assessed at presentation, third, sixth and 12th month follow-up. In Group 1, spectacles (at presentation) and occlusion therapy (1 month) were advised.

RESULTS

In Group 1, the mean CT and MT were higher whereas LogMAR BCVA and MVD were lower than Groups 2 and 3 at presentation. In Group 1, post occlusion therapy, the mean CT and MT decreased whereas LogMAR BCVA and MVD increased. There was no significant change in RNFLT in Group 1 as compared to Groups 2 and 3, pre- and post occlusion therapy.

CONCLUSION

CT and MT in amblyopic eyes were significantly higher. Following occlusion therapy, CT decreased in each follow-up but was not significant whereas MT decreased significantly at the last follow-up visit. There was no difference in RNFLT in amblyopic eyes as compared with normal fellow eyes and control eyes before and after occlusion therapy. MVD was lower in amblyopic eyes and increased during follow-up visits but was not significant.

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.

Features of the Choroidal Structure in Children With Anisometropic Amblyopia

PURPOSE

To examine the choroidal structure in children with anisometropic amblyopia using the binarization method.

METHODS

Thirty children with unilateral anisometropic amblyopia and 30 healthy age- and sex-matched controls were included in the study. Choroidal thickness was measured with optical coherence tomography. The choroidal layer was examined with the binarization method using ImageJ software (National Institutes of Health). The total choroidal area, stromal area, luminal area, luminal area to stromal area ratio, and choroidal vascular index were calculated. The values were compared by correlating the spherical equivalent (SE) (determined by an autorefractometer) with anterior chamber depth, axial length, central corneal thickness (measured by optical biometry), and choroidal thickness values.

RESULTS

Mean SE values were 3.75 ± 2.16 diopters (D) in the amblyopic eyes, 2.39 ± 2.09 D in the fellow eyes, and -0.27 ± 0.53 D in the control eyes. Best corrected visual acuity (BCVA) was 0.29 ± 0.11 logarithm of the minimum angle of resolution (logMAR) in the amblyopic eyes, 0.02 ± 0.04 logMAR in the fellow eyes, and 0 ± 0 logMAR in the control eyes. Choroidal thickness values were 351 ± 47 µm in the amblyopic eyes, 333 ± 55 µm in the fellow eyes, and 324 ± 51 µm in the control eyes. Luminal area to stromal area ratio values were 1.73 ± 0.13 in the amblyopic eyes, 1.76 ± 0.15 in the fellow eyes, and 2.02 ± 0.25 in the control eyes. Choroidal vascular index values were 63% ± 0.02 in the amblyopic eyes, 64% ± 0.02 in the fellow eyes, and 66% ± 0.03 in the control eyes. BCVA, SE, choroidal thickness, luminal area to stromal area ratio, and choroidal vascular index were significantly different in each group. The total choroidal area, luminal area, and stromal area were similar in all eyes. No correlation was found between choroidal vascular index and choroidal thickness, anterior chamber depth, axial length, and central corneal thickness.

CONCLUSIONS

In children with anisometropic amblyopia, the total choroidal area was relatively larger in both the amblyopic and the fellow eyes compared to the control eyes. Due to the higher stromal area and lower luminal area, both the amblyopic and the fellow eyes also had lower choroidal vascular index values than control eyes. [J Pediatr Ophthalmol Strabismus. 2022;59(5):320-325.].

Correlation Between Laser Speckle Flowgraphy and OCT-Derived Retinal and Choroidal Metrics in Healthy Human Eye

Purpose

To investigate the correlation between laser speckle flowgraphy (LSFG) signals and the quantitative metrics derived from optical coherence tomography (OCT) in normal eyes.

Methods

LSFG, OCT, and OCT angiography (OCTA) imaging were performed on normal participants using a custom-designed LSFG system and a commercial swept-source OCT system. Mean (PWM) and amplitude (PWA) of the LSFG pulse waveform were selected to quantify the LSFG signals. Retinal and choroidal maps were obtained using the standard 6 × 6 mm OCT and OCTA scans. Structural and vascular metrics maps, including thickness, vessel area density, vessel skeleton density, and vessel diameter index of the retina, and choroidal thickness (CT), choroidal vessel volume (CVV) and choroidal vessel index (CVI), were employed to quantify the retinal and choroidal properties. Correlation analysis was then performed between the LSFG, retinal, and choroidal metrics maps.

Results

Twelve healthy participants aged 23 to 36 years were enrolled in this study. The spatial distribution of the PWM and PWA values was highly correlated with that of the CT and CVV metrics. On average, Spearman correlation coefficients (ρ) were 0.80 and 0.78 (all P < 0.001) for the correlations between PWM and CT and CVV, respectively, and were 0.61 and 0.63 (all P < 0.05) for the correlations between PWA and CT and CVV, respectively. In comparison, both PWM and PWA were generally weak or not correlated with all the retinal metrics and CVI.

Conclusions

LSFG signals were positively correlated with the choroidal thickness and vessel volume, suggesting choroidal blood flows dominate the LSFG signals at the area absent of large retinal vessels.

Translational Relevance

This study illustrates the dominant source of the LSFG signals in the eye.

Changes in choroidal circulation and pulse waveform in a case of pregnancy-induced hypertension with serous retinal detachment

Purpose

We aimed to examine the changes in choroidal blood flow (CBF), choroidal pulse waveform, and central choroidal thickness (CCT) in a case of pregnancy-induced hypertension (PIH) using laser speckle flowgraphy (LSFG) and enhanced depth imaging optical coherence tomography (EDI-OCT) before and after treatment with antihypertensive drugs.

Observations

A 24-year-old Japanese woman diagnosed with PIH presented with complaints of worsening and blurred vision in the right eye. Funduscopic findings at the initial visit showed serous retinal detachment (SRD), retinal hemorrhage, and arterial tortuosity. The LSFG color map showed a warm color. Macular mean blur rate (MBR), which is an index of relative blood flow velocity, in both eyes was high, along with choroidal thickening. Blowout time (BOT), which indicates the rate of time in which the MBR is greater than half the amplitude during one heartbeat, was low and acceleration time index (ATI), which represents the time-to-peak of MBR, was high. Several weeks after treatment with antihypertensive drugs, the CBF and ATI gradually decreased with regression of the SRD and thinning of the CCT. On the other hand, BOT gradually increased after treatment, showing a significant decrease in vascular resistance. Ocular perfusion pressure decreased after treatment because of the reduction in blood pressure.

Conclusions and Importance

LSFG might reveal choroidal overperfusion and increased vascular resistance, along with SRD and choroidal thickening, in a patient with PIH with reversal after treatment with antihypertensive drugs. These findings demonstrate the importance of evaluation of ocular blood flow and vascular resistance in women with PIH in order to routinely assess the clinical and systemic condition.

Effect of keratorefractive surgery on choroidal thickness in anisometropic amblyopia

PURPOSE

To evaluate postoperative change in choroidal thickness (CT) in patients with anisometropic amblyopia undergoing keratorefractive surgery.

METHODS

Anisometropic amblyopic patients and nonamblyopic patients who underwent keratorefractive surgery were included in the study. The eyes were divided into three groups. Group 1 consisted of eyes with anisometropic amblyopia, group 2 were the nonamblyopic fellow eyes, and group 3 (control group) were nonamblyopic eyes which had undergone keratorefractive surgery. At the third postoperative month, the CT of these eyes were measured by Enhanced Depth Imaging OCT (EDI-OCT). The choroidal thickness (CT) was measured in the subfoveal area and at 500 micron intervals nasally and temporally.

RESULTS

Twenty-three anisometropic amblyopia patients with amblyopic and fellow eyes and 23 control eyes were enrolled. The mean subfoveal choroidal thickness (CT) was 387.3±168.8μm in group 1, 412.2±88.8μm in group 2 and 337.3±99μm in group 3 (P: 0.019). Group 1 and group 2 showed higher choroidal thickness (CT) in the nasal and temporal quadrants than group 3 (P: 0.03, P: 0.04). At the third postoperative month, central foveal choroidal thickness was 356.6±115.5μm in group 1, 375.1±112.5μm in group 2 and 284.4±98.9μm in group 3 (P: 0.071). Choroidal thickness (CT) in the nasal and temporal quadrants at the third postoperative month was also similar (P: 0.210, P: 0.103).

CONCLUSIONS

The macular choroid is thicker in amblyopic eyes and non-amblyopic fellow eyes than in the nonamblyopic controls. Improved fixation after refractive surgery may normalize CT.

Choroidal thickness and ocular growth in childhood

The involvement of the choroid in ocular growth regulation has been postulated in studies showing that refractive errors correlate with alterations in choroidal thickness (ChT). The advent of optical coherence tomography imaging has enabled qualitative and quantitative assessment of the choroid. In children, ChT changes correlate with a number of ocular pathologies, including myopia, retinopathy of prematurity, and amblyopia. We synthesize mechanisms and evidence regarding choroidal thickness variation during childhood. Subfoveal ChT is influenced by a number of factors including age, ethnicity, gender, axial length, and intraocular pressure. Myopic eyes have thinner choroids compared to emmetropic and hyperopic eyes. ChT may in fact serve as a marker of myopic progression, as ChT thinning occurs early during myopic development, but this association has not been established quantitatively. In addition, subfoveal ChT appears thicker in amblyopic eyes, while prematurity and retinopathy of prematurity may be associated with thinner ChT. Overall, both animal models and clinical research indicate that ChT induces or reflects physiological changes in the eye pertaining to ocular growth or maturation.

Imaging Amblyopia: Insights from Optical Coherence Tomography (OCT)

Amblyopia refers to visual impairment resulting from perturbations in visual experience during visual development, typically secondary to strabismus, uncorrected refractive error, and/or deprivation. Amblyopia has traditionally been considered a cortical disease, but the depth of our understanding of this complex neurodevelopmental condition is limited by our ability to appreciate structural pathophysiology in the visual pathway. Recent advances in Optical Coherence Tomography (OCT) have facilitated numerous studies of the structural changes in the retina and optic nerve, thereby expanding our appreciation for the pathogenesis of this condition. In this review, we summarize findings from studies evaluating retinal, retinal nerve fiber layer, and choroidal thickness changes in patients with amblyopia. Focusing on the largest and most recent studies, we discuss common limitations and confounding variables in these studies. We summarize recent advances in ocular imaging technology and reconcile the findings of early histological reports with those of structural OCT in amblyopia.

Effect of amblyopia treatment on choroidal thickness in hypermetropic anisometropic amblyopia using swept-source optical coherence tomography

Background

Recent studies using optical coherence tomography (OCT) have indicated that choroidal thickness (CT) in the anisometropic amblyopic eye is thicker than that of the fellow and normal control eyes. However, it has not yet been established as to how amblyopia affects the choroid thickening. The purpose of the present study was to investigate the effect of amblyopia treatment on macular CT in eyes with anisometropic amblyopia using swept-source OCT.

Methods

Thirteen patients (mean age: 6.2 ± 2.4 years) with hypermetropic anisometropic amblyopia were included in this study. Visual acuity (VA), axial length (AL), and CT were measured at the enrollment visit and at the final visit, after at least 6 months of treatment. CT measurements were corrected for magnification error and were automatically analyzed using built-in software and divided into three macular regions (subfoveal choroidal thickness (SFCT), center 1 mm, and center 6 mm). A one-way analysis of covariance using AL as a covariate was performed to determine whether CT in amblyopic eyes changed after amblyopia treatment.

Results

The average observation period was 22.2 ± 11.0 months. After treatment, VA (logMAR) improvement in the amblyopic eyes was 0.41 ± 0.19 (p < 0.001). SFCT, center 1 mm CT, and center 6 mm CT were significantly thicker in the amblyopic eyes compared with the fellow eyes both before and after treatment (p < 0.05 for all comparisons). There were no significant changes in SFCT, center 1 mm CT, or center 6 mm CT before and after treatment in the amblyopic (p = 0.25, 0.21, and 0.84, respectively) and fellow (p = 0.75, 0.84, and 0.91, respectively) eyes. The correlation between changes in logMAR versus changes in CT after treatment was not significant.

Conclusions

Although VA in amblyopic eyes was significantly improved after treatment, the choroid thickening of anisometropic amblyopic eyes persisted, and there was no significant change found in the CT after the treatment. Our findings suggest that thickening of the CT in amblyopia is not directly related to visual dysfunction.

Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy

Purpose

The present study aimed to examine changes in optic nerve head (ONH) blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal) with decreased ocular perfusion pressure (OPP) during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant.

Methods

This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR), which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP) elevation of approximately 15 mmHg in the subjects without systemic disorders.

Results

The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P < 0.05). However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P = 0.23).

Conclusions

There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.