Non-vascular smooth muscle cells in the human choroid: distribution, development and further characterization

BCLA CLEAR presbyopia: Mechanism and optics

With over a billion adults worldwide currently affected, presbyopia remains a ubiquitous, global problem. Despite over a century of study, the precise mechanism of ocular accommodation and presbyopia progression remains a topic of debate. Accordingly, this narrative review outlines the lenticular and extralenticular components of accommodation together with the impact of age on the accommodative apparatus, neural control of accommodation, models of accommodation, the impact of presbyopia on retinal image quality, and both historic and contemporary theories of presbyopia.

The structure and function of the human choroid

In this manuscript, the structure of the human choroid is reviewed with emphasis of the macro- and microscopic anatomy including Bruch's membrane, choriocapillaris, Sattler's and Haller's layer, and the suprachoroid. We here discuss the development of the choroid, as well as the question of choroidal lymphatics, and further the neuronal control of this tissue, as well as the pathologic angiogenesis. Wherever possible, functional aspects of the various structures are included and reviewed.

Differences in choroidal responses to near work between myopic children and young adults

BACKGROUND

Near work is generally considered as a risk factor for myopia onset and progression. This study aimed to investigate the choroidal responses to a brief-period of near work in children and young adults.

METHODS

Thirty myopic medical students (aged 18-28 years) and 30 myopic children (aged 8-12 years) participated in this study. The submacular total choroidal area (TCA), luminal area (LA), stromal area (SA), choroidal vascularity index (CVI) and choriocapillaris flow deficit (CcFD), as well as subfoveal choroidal thickness (SFCT) were measured with swept-source optical coherence tomography/optical coherence tomography angiography (SS-OCT/OCTA) before and immediately after 20 min, 40 min, 60 min of near work at a distance of 33 cm.

RESULTS

In adults, 20 min of near work induced a significant reduction in SFCT (- 5.1 ± 6.5 μm), LA [(- 19.2 ± 18.6) × 103 μm2], SA [(- 8.2 ± 12.6) × 103 μm2] and TCA [(- 27.4 ± 24.9) × 103 μm2] (all P < 0.01). After 40 min of near work, LA was still reduced [(- 9.4 ± 18.3) × 103 μm2], accompanied with a decreased CVI (- 0.39% ± 0.70%) and an increased CcFD (0.30% ± 0.78%) (all P < 0.05). After 60 min of near work, CVI was still reduced (- 0.28% ± 0.59%), and CcFD was still increased (0.37% ± 0.75%) (all P < 0.05). In children, 20 min of near work induced a significant increase in CcFD (0.55% ± 0.64%), while 60 min of near work induced increases in SA [(7.2 ± 13.0) × 103 μm2] and TCA [(9.7 ± 25.3) × 103 μm2] and a reduction in CVI (- 0.28% ± 0.72%) (all P < 0.05). Children exhibited lower near work-induced LA and TCA reduction than adults, with a mean difference of - 0.86% and - 0.82%, respectively (all P < 0.05).

CONCLUSIONS

The temporal characteristics and magnitude of changes of choroidal vascularity and choriocapillaris perfusion during near work was not identical between children and adults. The initial response to near work was observed in choriocapillaris in children, whereas it was observed in the medium- and large-sized vessels in adults.

TRIAL REGISTRATION

Clinical Trial Registry (ChiCTR), ChiCTR2000040205. Registered on 25 November 2020, https://www.chictr.org.cn/bin/project/edit?pid=64501 .

Evaluation of peripapillary choroidal vascularity index in young smokers

Purpose: This retrospective study aimed to compare the peripapillary choroidal vascularity index (CVI) between young smokers who smoked less than 5 packs/year and non-smokers.Methods: The study included 52 smokers and 67 non-smokers, and comprehensive eye examinations were performed on all participants. Axial lengths (AL) were measured, and peripapillary enhanced depth imaging optical coherence tomography (EDI-OCT) images were obtained and evaluated using the Open Source ImageJ software. The CVI, total choroidal area (TCA), luminal area (LA), stromal area (SA), and retinal nerve fibre layer (RNFL) quadrants were compared between the two groups.Results: The mean age of the smokers was 23.76 ± 1.84 years, and for non-smokers, it was 23.98 ± 2.18 years. The mean peripapillary CVI for smokers was 0.65 ± 0.08, and for non-smokers, it was 0.67 ± 0.03. No statistically significant difference in CVI was observed between the two groups. However, statistically significant differences were found in the temporal inferior (TI), temporal superior (TS), nasal inferior (NI), and nasal superior (NS) quadrants of the RNFL between the two groups (p < 0.05). There was no correlation between the number of packs/year and CVI values in the smoking group (r = 0.031, p = 0.826).Conclusion: The study revealed no significant difference in CVI among young smokers who smoked less than 5 packs/year compared to non-smokers. However, there was a statistically significant decrease in the TI, TS, NI, and NS quadrants of the RNFL in early-age smokers.

Urocortin-positive nerve fibres and cells are present in the human choroid

BACKGROUND

Choroidal vascular regulation is mediated by the autonomic nervous system in order to gain proper blood flow control. While the mechanisms behind this control are unknown, neuroregulatory peptides are involved in this process. To better understand choroidal function, we investigate the presence of urocortin-1 (UCN), a neuroregulatory peptide with vascular effects, in the human choroid and its possible intrinsic and extrinsic origin.

METHODS

Human choroid and eye-related cranial ganglia (superior cervical ganglion- SCG, ciliary ganglion-CIL, pterygopalatine ganglion-PPG, trigeminal ganglion-TRI) were prepared for immunohistochemistry against UCN, protein-gene product 9.5 (PGP9.5), substance P (SP), tyrosine hydroxylase (TH) and vesicular acetylcholine transporter (VAChT). For documentation, confocal laser scanning microscopy was used.

RESULTS

In choroidal stroma, UCN-immunoreactivity was present in nerve fibres, small cells and intrinsic choroidal neurons (ICN). Some UCN+ nerve fibres colocalised for VAChT, while others were VAChT. A similar situation was found with SP: some UCN+ nerve fibres showed colocalisation for SP, while others lacked SP. Colocalisation for UCN and TH was not observed. In eye-related cranial ganglia, only few cells in the SCG, PPG and TRI were UCN+, while many cells of the CIL displayed weak UCN immunoreactivity.

CONCLUSION

UCN is part of the choroidal innervation. UCN+/VAChT+ fibres could derive from the few cells of the PPG or cells of the CIL, if these indeed supply the choroid. UCN+/SP+ fibres might originate from ICN, or the few UCN+ cells detected in the TRI. Further studies are necessary to establish UCN function in the choroid and its implication for choroidal autonomic control.

Targeted surface marker screening on neuronal structures in the human choroid

While choroidal neuronal control is known to be essential for retinal and ocular health, its mechanisms are not understood. Especially, the local choroidal innervation mediated by intrinsic choroidal neurons (ICN) remains enigmatic. Neuronal functionality depends on the synaptic neurotransmitters and neuroregulatory peptides involved as well as from membrane components presented on the cell surface. Since the neuronal surface molecular expression patterns in the choroid are currently unknown, we sought to determine the presence of various cluster-of-differentiation (CD) antigens in choroidal neuronal structures with a particular focus on ICN. Human choroids were prepared for immunohistochemistry and the pan-neuronal marker PGP9.5 was combined with CD15, CD24, CD29, CD34, CD46, CD49b, CD49e, CD56, CD58, CD59, CD71, CD81, CD90, CD146, CD147, CD151, CD165, CD171, CD184, CD200, CD271 and fluorescence- and confocal laser scanning-microscopy was used for documentation. The following antigens were found to be co-localized in PGP.9.5+ nerve fibers and ICN perikarya: CD29, CD34, CD56, CD81, CD90, CD146, CD147, CD151, CD171, CD200 and CD271, while all other CD markers where not detectable. Whereas CD24^- and CD59^- immunoreactivity was clearly absent in ICN perikarya, some neural processes of the choroidal stroma displayed CD24 and CD59 immunopositivity. While a multitude of the aforementioned CD-markers were indeed detected in nervous structures of the choroid, the CD24⁺ and CD59⁺ nerve fibers most likely have extrinsic origin from cranial ganglia since ICN cell bodies were found to lack both markers. These findings illustrate how the detailed analysis of CD molecules described here opens novel avenues for future functional studies on choroidal innervation and its control.

Choroidal Thickness Profiles and Associated Factors in Myopic Children

SIGNIFICANCE

This study addresses the lack of choroidal thickness (ChT) profile information available in European children and provides a baseline for further evaluation of longitudinal changes in ChT profiles in myopic children as a potential biomarker for myopia treatment and identifying children at risk of myopic progression.

PURPOSE

This study aimed to investigate ChT profiles and associated factors in myopic children.

METHODS

Baseline data of 250 myopic children aged 6 to 16 years in the Myopia Outcome Study of Atropine in Children clinical trial were analyzed. Choroidal thickness images were obtained using swept-source optical coherence tomography (DRI-OCT Triton Plus; Topcon Corporation, Tokyo, Japan). The macula was divided into nine Early Treatment of Diabetic Retinopathy Study locations with diameters of 1, 3, and 6 mm corresponding to the central fovea, parafoveal, and perifoveal regions. Multiple linear regression models were used to investigate determinants of ChT.

RESULTS

Choroidal thickness varied across the macular Early Treatment of Diabetic Retinopathy Study locations ( P < .001): thickest in the perifoveal superior region (mean ± standard deviation, 249.0 ± 60.8 μm) and thinnest in the perifoveal nasal region (155.1 ± 50.3 μm). On average, ChT was greater in all parafoveal (231.8 ± 57.8 μm) compared with perifoveal (218.1 ± 49.1 μm) regions except superiorly where the ChT was greater in the perifoveal region. Longer axial length and higher myopic spherical equivalent refraction were consistently associated with thinner ChT at all locations in the multiple linear regression models. Asian race was significantly associated with thinner ChT only at parafoveal and perifoveal superior regions after Bonferroni correction ( P = .004 and P = .001, respectively).

CONCLUSIONS

Choroidal thickness was thinnest in the nasal macular region and varied systematically across all macular locations, with axial length and spherical equivalent refraction being the strongest determinants of ChT. Longitudinal evidence will need to evaluate whether any differences in ChT profiles are predictive of myopic progression and to determine the role of ChT measurements in identifying myopic children most in need of myopia control treatment.

Evaluation of Choroidal Vascular Structure in Hyperopic Anisometropic Amblyopia

Objectives

The aim of the study was to investigate the choroidal structure of patients with anisohypermetropic amblyopia compared to that of healthy eyes in controls of the same age.

Methods

The study comprises three groups: One group was the amblyopic eyes of patients with anisometropic hypermetropia (AE group), another group was the fellow eyes of patients with anisometropic hypermetropia (FE group), and a final group of healthy controls. Both the choroidal thickness (CT) and choroidal vascularity index (CVI) values were obtained using the spectral-domain optical coherence tomography (OCT) method of improved depth imaging (EDI-OCT; Heidelberg Engineering GmbH, Spectralis, Germany, Heidelberg).

Results

This study included 28 anisometropic amblyopic patients (AE and FE groups) and 35 healthy controls. Regarding the distribution of ages and sexes (p=0.813 and p=0.745), the groups were the same. The mean best-corrected visual acuity in AE, FE, and the control group was 0.58±0.76, 0.008±1.30, and 0.004±1.20 logMAR units, respectively. There was a significant difference in terms of CVI, luminal area (LA), and all the CT values between groups. Post hoc univariate analyses indicated that CVI and LA were significantly higher in AE compared to FE and the control group (p<0.05, for each). The temporal, nasal, and subfoveal CT values were considerably higher in AE compared to FE and the control groups (p<0.05, for each). However, there was no difference between FE and the control group (p>0.05, for each).

Conclusion

The AE group had larger LA, CVI, and CT values compared to the FE and control groups. These results show that choroidal changes in amblyopic eyes in children are permanent in adulthood if untreated and are involved in the pathogenesis of amblyopia.

Optical coherence tomography in the diagnosis and monitoring of congenital and juvenile glaucoma

Optical coherence tomography (OCT) in everyday routine practice is the method of choice for the instrumental diagnosis of glaucoma in adults. As a non-invasive and safe method of visualizing structural changes in the retina and the optic nerve, the method is of particular value in pediatric practice. At the same time, OCT diagnostics in children is associated with certain difficulties, both during the study and when interpreting the scan results.

This review summarizes the data from the literature and our own research in the diagnosis and monitoring of congenital and juvenile glaucoma from the standpoint of our own long-term clinical experience in using optical coherence tomography. We consider the physiological changes of the retina and optic nerve, attention is focused on the need to create a pediatric regulatory database of retinal thickness, the factors that determine the normal range of the data obtained and allow distinguishing physiological processes from pathological ones are identified. Clinical cases confirming the value of OCT in combined pathology are presented as examples.

In vivo analysis of ciliary muscle in myopic Chinese young adults using ArcScan Insight® 100

OBJECTIVE

To analyse the morphological characteristics of the ciliary muscle (CM) and to explore its relationship with different ocular biometric parameters in myopic young Chinese adults.

METHODS

This observational, cross-sectional study included 50 right eyes from 50 myopic adults. The CM area (CMA), CM thickness (CMT) and CM length (CML) were measured using the ArcScan Insight^® 100. CMT was determined at three points: 1.0 mm (CMT-1), 2.0 mm (CMT-2) and 3.0 mm (CMT-3) posterior to the scleral spur. CML was measured on the scleral (CMLs) and vitreous (CMLv) aspects. The spherical equivalent refraction (SER), axial length (AL) and subfoveal choroidal thickness (SFCT) were examined to determine their associations with CM parameters (CMA, CML and CMT).

RESULTS

The mean SER and AL were -4.39 ± 2.29 D and 25.61 ± 1.15 mm, respectively. Compared with the nasal CMA, CML and CMT (CMT-1, CMT-2 and CMT-3) findings, the temporal CM parameters (CMA, CMLs, CMLv, CMT-1, CMT-2 and CMT-3) were found to be significantly thicker (all p < 0.001, except CMLv and CMT-1; p < 0.01). The nasal CMA was associated with the average corneal curvature (r = 0.30, p = 0.03) and SER (r = -0.30, p = 0.04). Nasal and temporal CMT-2 were negatively correlated with SER (r = -0.33 and -0.32, respectively, both p < 0.05). There was no correlation between CM parameters (except nasal CMLs, r = 0.31, p = 0.03) and SFCT, or between CM parameters and either the AL or anterior chamber depth (all p > 0.05).

CONCLUSION

These results suggest that there is temporal versus nasal asymmetry of the CM. CMA, CMT or CML did not vary with axial growth of the eye. The CM is not simply stretched as the eye elongates in myopic young adults.

Wide-field choroidal thickness and vascularity index in myopes and emmetropes

PURPOSE

To study regional variations in choroidal thickness (CT), luminal thickness and stromal thickness of the choroid, and choroidal vascularity index (CVI) in low myopic and emmetropic eyes using wide-field optical coherence tomography (OCT).

METHODS

Sixty-nine healthy young adults between 20 and 38 years of age participated in this study, including 40 low myopes (mean ± SD spherical equivalent (MSE) refractive error: -3.00 ± 1.39 D, range: -6.00 to -0.62 D) and 29 emmetropes (MSE: -0.05 ± 0.09 D, range: -0.25 to +0.12 D). Wide-field CT, luminal thickness, stromal thickness and CVI were measured across five eccentricities (fovea, parafovea, perifovea; near-periphery and periphery) and four quadrants (nasal, temporal, inferior and superior), in vertical and horizontal meridians, while controlling for a range of extraneous factors potentially influencing the CT. Custom-written software was used to segment and binarize the OCT images.

RESULTS

Wide-field CT, luminal thickness and stromal thickness, averaged across all participants, exhibited significant topographical variation, with the foveal (379 ± 8 µm, 200 ± 4 µm, 179 ± 4 µm, respectively) and peripheral (275 ± 8 µm, 161 ± 4 µm, 114 ± 4 µm, respectively) regions presenting the thickest and thinnest regions (all p < 0.001). Wide-field CVI showed a progressively higher percentage (greater vascularity) with increasing eccentricity from the fovea towards the periphery (p < 0.001). Macular CT and stromal choroidal thickness were significantly thinner in myopes compared to emmetropes (p < 0.05). Myopes (55.7 ± 0.3%) showed a slightly higher CVI compared with emmetropes (54.4 ± 0.4%) (p < 0.05).

CONCLUSIONS

Low myopia in young adults was associated with significant choroidal thinning across the macular, but not extramacular regions, with this decrease in choroidal thickness mostly attributed to thinning in the stromal component of the choroid, rather than the luminal (vascular) component.

Applications of Multimodal Imaging in Central Serous Chorioretinopathy Evaluation

Central serous chorioretinopathy (CSCR) is a macular disease characterized by serous retinal detachment commonly involving the macular region. CSCR has a wide spectrum of clinical presentations. Although a significant proportion of CSCR cases are self-limiting, patients can suffer from persistent or recurrent disease, sometimes complicated with choroidal neovascularization, resulting in permanent visual loss. Multimodal imaging, including fluorescein angiography, indocyanine green angiography, fundus autofluorescence, and optical coherence tomography, has advanced the diagnosis and classification of CSCR cases. Evolution of new imaging techniques including optical coherence tomography angiography, wide-field imaging, and en face reconstruction imaging has also contributed to better understandings of the pathophysiology of CSCR. This review article summarizes the features of multimodal imaging for CSCR and discusses the application of such features in evaluating the disease.

Choroidal and Retinal Thickness and Axial Eye Elongation in Chinese Junior Students

Purpose

To explore the associations between macular choroidal and retinal thickness and axial elongation in non-myopic and myopic junior students.

Methods

In this school-based longitudinal observational study, axial length was measured by optical low-coherence reflectometry, and choroidal thickness and retinal thickness were measured by spectral-domain optical coherence tomography. Myopia was defined as non-cycloplegic objective spherical equivalent refraction ≤ −0.50 diopters. Structural equation modeling and multiple linear regression models were used to analyze the associations between baseline choroidal and retinal thickness with axial elongation.

Results

Out of 1307 students examined at baseline in 2017, 1197 (91.58%) returned for follow-up examination in 2018, with a median age of 12.00 years (interquartile range [IQR], 1.00) and included 667 boys (55.72%). Within a 1-year period, the median axial elongation of right eyes was 230 µm (IQR, 180) in boys and 200 µm (IQR, 160) in girls (P = 0.032). The thinner temporal choroidal thickness was associated with greater 1-year axial elongation only in myopic students (β, −0.20; 95% confidence interval [CI], −0.37, −0.03), the thinner temporal retinal thickness was associated with greater 1-year axial elongation in both non-myopic (β, −2.67; 95% CI, −4.52, −0.82) and myopic (β, −0.99; 95% CI, −1.68, −0.30) students, after adjustment for sex, age, and height. Subfoveal and nasal choroidal and retinal thickness were not significantly associated with axial elongation in either non-myopic or myopic students.

Conclusions

A thinner temporal choroid at age 12 years may predict greater 1-year axial elongation in myopic students, and a thinner temporal retina may predict greater 1-year axial elongation in both non-myopic and myopic students. This finding may help to identify children at risk and control axial elongation with potential preventive strategies.

Choroidal Vascularity Map in Unilateral Central Serous Chorioretinopathy: A Comparison with Fellow and Healthy Eyes

Background: To map the choroidal vascularity index and compare two eyes in patients with unilateral central serous chorioretinopathy (CSCR). Methods: This was a retrospective, observational study performed in patients with unilateral CSCR. Choroidal thickness (CT) and Choroidal vascularity index (CVI) were measured and mapped in various zones according to the early treatment diabetic retinopathy (ETDRS) grid. Results: A total of 20 CSCR patients (20 study and 20 fellow eyes) were included in the study. Outer nasal region CT was seen to be significantly lower than central CT (p = 0.042) and inner nasal CT (p = 0.007); outer ring CT was significantly less than central (p = 0.04) and inner ring (p = 0.01) CT in CSCR eyes. On potting all the CVI values against the corresponding CT values, a positive correlation was seen in CSCR eyes (r = 0.54, p < 0.01), which was slightly weaker in fellow eyes (r = 0.3, p < 0.01) and a negative correlation was seen in healthy eyes (r = −0.262, p < 0.01). Conclusions: Correlation between CVI and CT was altered in CSCR eyes as compared to fellow and normal eyes with increasing CVI towards the center of the macula and superiorly in CSCR eyes.

IMI Accommodation and Binocular Vision in Myopia Development and Progression

The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.

Macular irregularities of optical coherence tomographic vertical cross sectional images in school age children

The purpose of this study was to compare the incidences of macular irregularities of elementary school (ES) and junior high school (JHS) students. This was a prospective cross-sectional observational study of 122 right eyes of 122 ES students (8-9 years) and 173 right eyes of 173 JHS students (12-13 years). Vertical cross-sectional images of the macula were obtained by optical coherence tomography. The eyes were classified based on the vertical symmetry of the posterior pole, and then sub-classified as convex-, flat-, concave-, or dome-shaped based on the direction of the curvature of the retinal pigment epithelium. One hundred and two eyes (83.6%) were placed in the symmetrical group in the ES students and 149 eyes (86.1%) in the JHS students. Twenty eyes (16.4%) were placed in the asymmetric groups in the ES students and 24 eyes (13.9%) in the JHS students. In symmetrical group, 78 and 118 eyes had a convex-shape (76.4 and 79.2%), followed by 22 and 29 eyes of dome-shaped group (21.6 and 19.4%) in ES and JHS students respectively. Because the incidences of the posterior pole shapes were not significantly different between the groups, it is likely that the macular irregularities develop before the age of ES.

Current Choroidal Imaging Findings in Central Serous Chorioretinopathy

Background: Central serous chorioretinopathy (CSCR) is a chorioretinal disease affecting mostly middle age males. It is marked by the serous detachment of the neurosensory layer at the macula. This review of the literature provides a framework of the current characteristic/relevant imaging findings of CSCR. Although the pathogenesis of CSCR is unclear, the choroid plays a major role and its changes are fundamental to the diagnosis and treatment of CSCR. Methods: A systematic literature search focusing on current multimodal imaging for CSCR was performed. Only articles reporting on original clinical data were selected, studies in a language other than English were included only if an English abstract was provided. Additional sources included articles cited in the references list of the first selected articles. We deduced imaging findings based on current and relevant literature on the topic. Results: We found that sub foveal choroidal thickness (SFCT) and choroidal vascularity index (CVI) were greater in eyes with acute CSCR than in eyes with chronic CSCR or normal eyes. There was increased choroidal thickness (CT) in the macula compared to peripapillary region. In healthy eyes, the highest CVI was found in the nasal region followed by the inferior, temporal, and superior quadrant. The area with the least CVI was the macula. In eyes with CSCR, 100% had asymmetric dominant vortex veins compared to 38% in normal eyes. Conclusion: Choroidal imaging has advanced the diagnosis of CSCR. This has led to numerous imaging biomarkers like CVI, CT, and hyper-reflective dots for early detection and possible prognostication of CSCR. More techniques like wide field scans and en face imaging are being employed to characterize the choroid in CSCR.

[Choroid and optical defocus]

The review summarizes experimental and clinical data attesting to the important role the choroid plays in the development of refraction through optically oriented thickness changes and the release of growth factors. Because of its unique anatomical position, the choroid can influence the transmission of a cascade of chemical signals from the retina to the sclera and thereby affect the growth of the eye. Understanding the relationship between the optical defocus and the response of the choroid to it will help uncover the fundamental mechanisms for controlling eye growth and develop new strategies for preventing the progression of myopia.

CONTRACTILE OPTIC DISK AND PERIPHERAL AVASCULAR RETINA IN A CASE OF MORNING GLORY DISK ANOMALY

PURPOSE

To report a rare case of morning glory disk anomaly with a contractile optic disk and a peripheral avascular retina along with detailed spectral domain optical coherence tomography characteristics of the contractions.

METHODS

Serial fundus photographs and optical coherence tomography images were taken to study the characteristics of optic disk contractions. Fundus fluorescein angiography was performed to delineate the peripheral avascular retina in the same eye.

RESULTS

A 9-year-old boy presented to us with morning glory disk anomaly in the left eye. He had contractile motions of the optic disk around two to three times in a minute, with each contraction lasting for 4 seconds to 5 seconds. Serial spectral domain optical coherence tomography images could depict an anterior contraction of the optic disk along with the surrounding peripapillary staphyloma with no evidence of any subretinal fluid. Fundus examination of the left eye also suggested the presence of an avascular retina temporally, which was confirmed on fundus fluorescein angiography.

CONCLUSION

Our report provides detailed spectral domain optical coherence tomography images through the optic disk in morning glory disk anomaly during various phases of optic disk contractions. It also presents a second rare association of a peripheral avascular retina in the case.

New Insights on Choroidal Vascularity: A Comprehensive Topographic Approach

Purpose

To obtain a choroidal vascularity index (CVI) map of macular area on an Early Treatment Diabetic Retinopathy Study (ETDRS) grid.

Methods

The study was a cross-sectional study involving 30 eyes of 30 healthy individuals. In brief, a shadow-compensated automated algorithm was used to segment and binarize the individual optical coherence tomography (OCT) B-scans. This was followed by three-dimensional reconstruction of these processed B-scans to obtain the overall thickness and vascularity maps. ETDRS grid was overlaid on both the extrapolated thickness and vascularity maps to obtain the corresponding sector-wise CVI. The main outcome measure was to evaluate the topographical variation of CVI in the macular area.

Results

The mean age of the study participants was 44.33 ± 16.29 years (range, 18-70 years). CVI showed no significant difference in different rings, subfields, or quadrants of the ETDRS map. CVI had a negative correlation with age (r = -0.384, P = 0.03). There were no statistically significant differences between CVI of both eyes in either rings or the full ETDRS grid (P = 0.30) among normal subjects.

Conclusions

The variation in CVI does not follow similar patterns as seen in choroidal thickness (CT) in various locations. The novel choroidal vascularity mapping in the macular area may expand understanding on regional differences of choroidal vasculature in healthy eyes.

Analysis of Choroidal Vascularity in Children with Unilateral Hyperopic Amblyopia

This institutional case control study was carried out to compare choroidal vascularity (CV) in amblyopic eyes, fellow eyes, and control eyes in children with unilateral hyperopic amblyopia. Sixty-four eyes of 32 childeren with unilateral anisometropic hyperopic amblyopia and 38 eyes of 19 healthy children (controls), aged 3 to 16 years. Subfoveal choroidal thickness (CT) and CV were measured using spectral domain optical coherence tomography. The mean subfoveal CT of amblyopic eyes (338.9 ± 60.0 μm) was greater than that of fellow eyes (315.3 ± 63.3 μm, P = 0.043) and control eyes (313.0 ± 42.1 μm, P = 0.025). The mean CV of amblyopic eyes (0.715 ± 0.020) was greater than that of control eyes (0.700 ± 0.020, P < 0.001). While a positive correlation between CT and CV was found in normal eyes (r = 0.470, P = 0.004), a strong negative correlation existed in amblyopic eyes (r = −0.684, P < 0.001). In conclusion, although mean CV was higher in amblyopic eyes, the negative correlation between CT and CV may suggests insufficient blood supply to the outer retina and choroid in the affected eyes of patients with unilateral anisometropic hyperopic amblyopia.

Regional alterations in human choroidal thickness in response to short-term monocular hemifield myopic defocus

PURPOSE

To examine the regional changes in human choroidal thickness following short-term exposure to hemifield myopic defocus using optical coherence tomography (OCT).

METHODS

The central 26˚ visual field of the left eye of 25 healthy young adults (mean age 26 ± 5 years) was exposed to 60 min of clear vision (control session), +3 D full-field, +3 D superior retinal and +3 D inferior retinal myopic defocus, with the right eye occluded. Choroidal thickness across the central 5 mm (17°) macular region was examined before and after 60 min of defocus using a high-resolution, foveal centred vertical OCT line scan, with optical defocus simultaneously imposed using a Badal optometer and cold mirror system mounted on a Spectralis OCT device.

RESULTS

Averaged across the central 5 mm macular area, choroidal thickness decreased by -4 ± 7 μm during the control session (p = 0.01), most likely due to the unique stimulus conditions of this study. The mean macular choroidal thickness increased during full-field (+2 ± 8 μm), inferior retinal (+3 ± 7 μm) and superior retinal myopic defocus (+5 ± 9 μm), representing a significant thickening of the choroid compared to the control session (all p < 0.05). The defocus induced changes in macular choroidal thickness differed between the superior and inferior hemiretinal regions (F_{2.26, 54.27}  = 29.75, p < 0.001). When only the superior retina was exposed to myopic defocus, the choroid thickened in the superior region (+7 ± 8 μm, p < 0.001), but did not change significantly in the inferior region (+3 ± 9 μm, p = 0.12). When only the inferior retina was exposed to myopic defocus, the choroid thickened inferiorly (+4 ± 8 μm, p = 0.005), with no significant change observed in the superior region (+1 ± 8 μm, p = 0.46).

CONCLUSIONS

These findings provide evidence supporting a local regional choroidal response to myopic defocus in the human eye, with hemifield myopic defocus leading to significant thickening of the choroid localised to the retinal region exposed to defocus. The novel finding of a localised response of the human choroid to hemifield myopic defocus, particularly in the superior hemiretina, may have important implications in optimising the optical design of myopia control interventions.

Wide-field choroidal thickness in myopes and emmetropes

There is a paucity of knowledge regarding the normal in-vivo thickness of the choroid beyond the macula (~17°). In this study, the choroidal thickness of 27 healthy young adults was examined across the macular (the central 5 mm including the fovea, parafovea, and perifovea) and extra-macular (a 5-14 mm annulus including the near-periphery and periphery) regions using wide-field optical coherence tomography, and compared between emmetropes (n = 14) and myopes (n = 13). The choroid progressively thinned beyond the parafovea (350 ± 86 µm) towards the periphery (264 ± 44 µm), and was thickest superiorly (355 ± 76 µm) and thinnest nasally (290 ± 79 µm). Choroidal thickness also varied with refractive error; myopes exhibited a thinner choroid than emmetropes in the macular region (311 ± 88 vs. 383 ± 66 µm), however, this difference diminished towards the periphery (251 ± 48 vs. 277 ± 37 µm). Meridional variations in choroidal thickness were not different between myopes and emmetropes. In conclusion, the choroid was thickest within the perifovea; thinned substantially towards the periphery, and exhibited the minimum and maximum peripheral thinning superiorly and nasally across a 55° region respectively. Choroidal thinning associated with myopia was more pronounced in the macular than extra-macular regions.

Evaluation of Choroidal Layer Thickness in Central Serous Chorioretinopathy

Purpose

To evaluate medium and large choroidal vessel layer thickness (MCVT and LCVT, respectively) in eyes with acute and chronic central serous chorioretinopathy (CSC) in comparison with age-matched controls.

Methods

The study included 96 eyes of 96 patients with CSC, including 53 eyes with acute CSC, 43 eyes with chronic CSC, and 30 eyes of 30 age-matched normal subjects. Manual measurements of subfoveal choroidal thickness (SFCT), MCVT, and LCVT at subfoveal and 750 μm nasal and temporal to the fovea locations were made on enhanced depth imaging optical coherence tomography (EDI-OCT) of the macula in all subjects using ImageJ software (National Institutes of Health, Bethesda, MD, USA).

Results

SFCT in acute CSC was significantly larger than that in healthy eyes (P = 0.0001). SFCT in acute CSC did not differ significantly from that in chronic CSC eyes. Subfoveal LCVT and MCVT in acute CSC eyes were greater than those in healthy eyes (P = 0.02 and P = 0.03, respectively). Mean SFCT and MCVT in chronic CSC eyes were significantly larger than those in control eyes (P = 0.01 and P = 0.04, respectively). No significant difference in LCVT was observed between chronic and control eyes.

Conclusion

Choroidal vasculature is altered in both acute and chronic CSC. SFCT, MCVT, and LCVT are higher in eyes with acute CSC. The thickening of medium choroidal vessels is still detectable in chronic CSC compared to control eyes.

Choroidal changes in human myopia: insights from optical coherence tomography imaging

The choroid is a vascular tissue which plays a range of critical roles in the normal physiology of the eye, such as supplying the outer retina with oxygen and nutrients and the regulation of intraocular pressure. There is also substantial evidence, particularly from animal studies, that the choroid plays an important role in the regulation of eye growth and the development of common refractive errors like myopia. In recent years, advances in optical coherence tomography technology have improved our ability to image and measure the choroid in the human eye. Research using this technology over the past decade has dramatically improved our knowledge of the normal choroid, and its potential role in the regulation of eye growth and refractive error development. This review aims to provide an overview of recent work examining the normal human choroid, its changes with myopia and the possible role of the choroid in the mechanism regulating eye growth. Studies have demonstrated that choroidal thinning accompanies the development and progression of myopia, and have established a close link between eye growth and choroidal thickness changes. Dramatic thinning of the choroid is seen with high myopia, and associations are also observed between choroidal thinning and reduced vision, and the development of retinal pathology associated with high myopia. In the short-term, environmental factors known to be associated with myopia development and more rapid eye growth typically lead to a thinning of the choroid, whereas factors linked to a slowing of eye growth are typically associated with short-term choroidal thickening. Collectively, these findings suggest that the choroid is an important biomarker of eye growth in the human eye, and additional research to better understand the human choroid is likely to further our knowledge of the signals and pathways regulating eye growth, myopia development and progression.

Optical coherence tomography and video recording of a case of bilateral contractile peripapillary staphyloma

Purpose

To report a case of bilateral contractile peripapillary staphyloma (CPS) examined by optical coherence tomography (OCT) and video recording.

Observation

We report the clinical history of a male infant with bilateral CPS. Two ophthalmic examinations under general anesthesia were performed during follow-up examinations. During the first fundus examination when the infant was 4 months old, we observed staphylomatous excavation around the optic disc, an almost normal disc appearance at the bottom of the excavation, and irregular contraction bilaterally. OCT images showed deep excavation around the optic disc bilaterally and hyperreflective tissue beneath the sclera in the right eye. During the second examination when the child was 4 years and 1 month, in addition to the previous fundus findings, the fundus examination showed white fibrous tissue on the optic disc and pigmentation around the optic disc in the right eye and a retinal cyst in the left eye. Bilateral simultaneous video recordings showed that the contractions were not synchronized between the eyes.

Conclusions

In a patient with bilateral CPS, we observed unsynchronized contraction between the eyes and the presence of sequential hyperreflective tissue under the sclera using bilateral ophthalmic approaches.

Short term effect of choroid thickness in the horizontal meridian detected by spectral domain optical coherence tomography in myopic children after orthokeratology

AIM

To investigate choroidal thickness changes in the horizontal meridian after orthokeratology.

METHODS

This is a prospective cross-sectional observed study. Subjects (n=30; 11.3±1.7y) with low-to-moderate myopia (-1.0 to -6.0 diopters), wore orthokeratology (Ortho-K) lenses for 3mo. Before and after Ortho-K, OCT scans were made through the fovea in the horizontal meridian. Choroid thickness around the fovea was acquired by custom software. The analyzed regions along the horizontal meridian were divided into 7 equal zones. Ocular parameters were measured by Lenstar LS 900 non-contact biometry.

RESULTS

Only the right eye ocular parameters were analyzed in this study. Before Ortho-K, choroidal thickness along the horizontal meridian was 273.7±31.8 µm in the temporal zone, 253.1±38.6 µm in the macula zone, and 194.8±52.2 µm in the nasal zone. After Ortho-K, the choroid was thicker in each horizontal zone (P<0.05). The increased thickness was greatest in the temporal zone (13.5±22.5 µm) and least in the nasal zone (8.4±14.2 µm). The axial length (AL) increased 0.02 mm (P>0.05). The choroid thickness change in each horizontal zone was negatively correlated with AL (r, -0.3 to -0.4; P<0.05) except one of the nasal zones.

CONCLUSION

In myopic children, the thickness of the choroid is greatest in the temporal zone and thinnest in the nasal zone. After nightly Ortho-K for 3mo, the thickness increase along the horizontal meridian. The choroid thickness changes are negatively correlated with the change of AL.

Retinal vessels functionality in eyes with central serous chorioretinopathy

Purpose

To analyse static characteristics and dynamic functionality of retinal vessels in eyes with central serous chorioretinopathy (CSCR) by means of Dynamic Vessel Analyzer (DVA).

Methods

Patients presenting with treatment-naïve CSCR and normal subjects (controls) matched for age and sex between May 2015 and November 2015 were enrolled in the study. Participants underwent a complete ophthalmological examination, including dynamic and static retinal vessels analysis by DVA.

Results

A total of 28 eyes of 28 subjects (14 eyes for each group) were included in the analysis. Dynamic analysis during stimulation by flickering light showed mean venous dilation of 3.3%±2.0% in patients with CSCR and 5.5%±2.6% in controls (p=0.0258); mean arterial dilation did not differ between patients and controls (3.2%±2.5% and 4.2%±1.5%, p=0.2). No differences were reported at static retinal analysis between patients with CSCR and control subjects. Subfoveal choroidal thickness as evaluated by optical coherence tomography was 438.6±86.1 µm in CSCR eyes, significantly increased compared with control subjects (301.5±72.5 µm, p=0.0001).

Conclusions

Dynamic analysis revealed a reduced retinal venous dilation in response to flicker light stimulation in CSCR eyes. The decreased retinal vein response to flicker light stimulation, possibly due to increased sympathetic tone and potentially leading to venous stasis, together with the increased choroidal thickness may help understand CSCR and give insights in its pathogenesis.

Choroidal Structure in Children with Anisohypermetropic Amblyopia Determined by Binarization of Optical Coherence Tomographic Images

Purpose

To compare the choroidal structure of the subfoveal area in the eyes of children with anisohypermetropic amblyopia to that of the fellow eyes and to age-matched controls using a binarization method of the images obtained by enhanced depth imaging optical coherence tomography (EDI-OCT).

Methods

This study was performed at Nara Medical University Hospital, Tokushima University Hospital, and Kagoshima University Hospital, Japan. Forty amblyopic eyes with anisohypermetropic amblyopia and their fellow eyes (5.9 ± 2.1 years, mean ± standard deviation), and 103 age-matched controls (6.7 ± 2.4 years) were studied. The control eyes were divided into myopic, emmetropic, and hyperopic eyes. The total choroidal area, luminal area and stromal area of the subfoveal choroid were measured by the binarization method. The luminal/stromal ratio and the axial length of the amblyopic eyes were compared to that of the control eyes.

Results

The total choroidal area in the amblyopic eyes was significantly larger than that of the fellow eyes (P = 0.005). The luminal/stromal ratio was significantly larger in the amblyopic eyes than that of the fellow eyes (P<0.001) and the control hyperopic eyes (P<0.001). There was a significant negative correlation between the luminal/stromal ratio and the axial length in the control eyes (r = -0.30, P = 0.001), but no significant correlation was found in the amblyopic eyes.

Conclusions

The choroidal structure of the amblyopic eyes was different from that of the fellow and the control hyperopic eyes. The choroidal changes are related to amblyopia.

Association of retinal thickness and optic disc-to-fovea angle to axial length of young healthy eyes

AIM

To determine the relationship between the axial length (AL) and the retinal thickness in the posterior pole and to the optic disc-to-fovea (ODF) angle of healthy eyes.

PROCEDURES

A prospective, observational cross-sectional study (registration number, UMIN000006040) of 64 healthy right eyes (mean age 26.0±4.5 years) was performed. The thickness of the 64 areas within the central 24° area were measured in the Spectralis spectral domain-optical coherent tomographic images obtained by posterior pole scans. Each area was 3°×3°. The ODF angle was measured in each fundus photograph. The relationships between the AL and the retinal thickness of each of the 64 areas and the ODF angle were investigated by linear regression analyses.

RESULTS

The mean AL was 25.0±1.3 mm and the mean ODF angle was 17.2°±1.0°. The average retinal thickness of the four areas around the fovea was constant and not significantly correlated with the AL. However, the retinal thicknesses of 54 of the other 60 areas were significantly and negatively correlated with the AL (R=-0.25 to -0.56, P<0.05). The ODF angle was also constant and not significantly correlated with the AL (R=-0.17, P=0.19).

CONCLUSION

The lack of significant correlations between the AL and the retinal thicknesses of the central 6° or the ODF angle suggests that there might be some feedback system to keep the central retinal thickness and ODF angle constant regardless of an elongation of the AL.

Chronologic versus biologic aging of the human choroid

Several aspects of chronologic and biologic aging in the human choroid are reviewed from the literature. They often reveal methodological problems for age-dependent changes of the following parameters: choroidal thickness, choroidal pigmentation, choroidal vasculature and blood flow, and choroidal innervation. On reinterpreting some data of studies concerning Bruch's membrane, changes observed at different age points seem more likely to be nonlinear. Concluding from the data presented so far, chronologic aging should not be used as a factor for physiological changes in the human choroid. Longitudinal study designs are necessary to further establish the impact of age. Meanwhile, a more biologic oriented model of aging processes in the choroid should be established, including specified conditions (e.g., light exposure and refractory state). This would help to define more individual strategies for prevention and early stages of a certain defined disease.

Optic disc contractility in morning glory disc anomaly

Morning glory disc anomaly is a sporadic congenital abnormality of the optic disc that is often unilateral. These eyes possess heterotropic smooth muscle and can undergo spontaneous contraction with transient vision loss. The authors report an unusual case of contractility of a morning glory disc anomaly induced by ocular massage.

The multifunctional choroid

The choroid of the eye is primarily a vascular structure supplying the outer retina. It has several unusual features: It contains large membrane-lined lacunae, which, at least in birds, function as part of the lymphatic drainage of the eye and which can change their volume dramatically, thereby changing the thickness of the choroid as much as four-fold over a few days (much less in primates). It contains non-vascular smooth muscle cells, especially behind the fovea, the contraction of which may thin the choroid, thereby opposing the thickening caused by expansion of the lacunae. It has intrinsic choroidal neurons, also mostly behind the central retina, which may control these muscles and may modulate choroidal blood flow as well. These neurons receive sympathetic, parasympathetic and nitrergic innervation. The choroid has several functions: Its vasculature is the major supply for the outer retina; impairment of the flow of oxygen from choroid to retina may cause Age-Related Macular Degeneration. The choroidal blood flow, which is as great as in any other organ, may also cool and warm the retina. In addition to its vascular functions, the choroid contains secretory cells, probably involved in modulation of vascularization and in growth of the sclera. Finally, the dramatic changes in choroidal thickness move the retina forward and back, bringing the photoreceptors into the plane of focus, a function demonstrated by the thinning of the choroid that occurs when the focal plane is moved back by the wearing of negative lenses, and, conversely, by the thickening that occurs when positive lenses are worn. In addition to focusing the eye, more slowly than accommodation and more quickly than emmetropization, we argue that the choroidal thickness changes also are correlated with changes in the growth of the sclera, and hence of the eye. Because transient increases in choroidal thickness are followed by a prolonged decrease in synthesis of extracellular matrix molecules and a slowing of ocular elongation, and attempts to decouple the choroidal and scleral changes have largely failed, it seems that the thickening of the choroid may be mechanistically linked to the scleral synthesis of macromolecules, and thus may play an important role in the homeostatic control of eye growth, and, consequently, in the etiology of myopia and hyperopia.

Morning glory disk anomaly: a computerized analysis of contractile movements with implications for pathogenesis

Excavated optic disk anomalies, such as morning glory disk anomaly, peripapillary staphyloma, and optic disk coloboma, are rare. Contractile movement of a given lesion is even rarer. Only 4 patients with morning glory disk anomalies accompanied by contractile movement have been reported. We offer a computerized analysis of the contraction, observable on a video recording of a patient with this disorder, with an explanation of the possible pathogenesis of the disorder.