ASYMMETRY IN MACULAR CHOROIDAL THICKNESS PROFILE BETWEEN BOTH EYES IN A HEALTHY POPULATION MEASURED BY SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

Interocular Symmetry of Choroidal Parameters in Patients with Diabetic Retinopathy with and without Diabetic Macular Edema

This study focuses on the interocular comparison of choroidal parameters in diabetic patients with diabetic retinopathy (DR) with and without diabetic macular edema (DME), as well as in patients with unilateral DME (present in only one eye). The aim of this study was to determine the symmetry in order to obtain better insights into the pathophysiology of diabetic choroidopathy. This retrospective single-center cross-sectional study included 170 eyes from 85 patients (61 with DR and 24 controls), divided into subgroups depending on the presence of DME. The patients underwent fluorescein angiography and spectral domain optical coherence tomography examination, and the analysis included various choroidal parameters: choroidal thickness, volume, and the choroidal vascularity index (CVI). In terms of the choroidal thickness, one eye of a patient with DR, regardless of the presence, absence, or unilaterality of DME, may be treated as representative for that patient. CVI proved symmetrical for controls and patients with DR without DME. However, there was some asymmetry of CVI in patients with bilateral or unilateral DME. There was no straightforward relationship between choroidopathy and DME. Other mechanisms were also involved in the pathogenesis.

Relationship between choroidal thickness and vascular density in young healthy population

BACKGROUND AND PURPOSE

The purpose is to analyze choroidal vascular density (VD) in healthy individuals and to compare it with choroidal thickness (CT).

MATERIALS AND METHODS

Cross-sectional study enrolling healthy individuals between 18 and 35 years old of Caucasian race and with an axial length (AL) 21-26 mm. Choroid was imaged with swept-source optical coherence tomography angiography (OCTA) Triton DRI (Topcon) and a macular cube of 6 x 6 mm was obtained. CT values were automatically given by the software. VD values were obtained through codifying colors of the VD map into numbers.

RESULTS

102 (51 patients) were analyzed. Mean age was 27.32 ± 3.94 years old, mean intraocular pressure was 18.07 ± 2.38 mmHg, and mean AL was 23.71 ± 0.66 mm. CT was higher in the vertical axis and lower when approaching nasal and temporal sides. The highest CT was in superior macula. The highest choroidal VD were in the fovea and in the juxtapapillary region. The lowest choroidal VD were found in superior and inferior macular areas. Moderate inverse correlations between CT and choroidal VD were found in the juxtapapillary and inferior regions.

CONCLUSIONS

The choroid has a thickness pattern that differs from retina. Choroidal vessels represent a very high percentage of choroid in the peripapillary region and in the fovea. On the contrary, superior and inferior macula reveals low values of VD.

Quantitative Assessment of Choroidal Thickness and Choroidal Vascular Features in Healthy Eyes Based on Image Binarization of EDI-OCT: A Single-Center Cross-Sectional Analysis in Chinese Population

PURPOSE

To quantify the structural changes in choroidal vessels and to observe choroid microstructural changes in different age and sex groups in a healthy Chinese population.

METHODS

Enhanced depth imaging optical coherence tomography (EDI-OCT) was employed to analyze the luminal area, stromal area, total choroidal area, subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), large choroidal vessel layer (LCVL), choriocapillaris-medium choroidal vessel layer, and LCVL/SFCT of the choroid in the subfoveal macular area within 1500 μm of the macula. We analyzed the age- and sex-related changes in the subfoveal choroidal structure.

RESULTS

A total of 1566 eyes from 1566 healthy individuals were included. The mean age of the participants was 43.62 ± 23.29 years, the mean SFCT of healthy individuals was 269.30 ± 66.43 μm, LCVL/SFCT percentage was 77.21 ± 5.84%, and the mean macular CVI was 68.39 ± 3.15%. CVI was maximum in the 0-10 years group, decreasing with age, and the lowest values occurred in the >80 years group; LCVL/SFCT was the lowest in the 0-10 years group, increasing with age and reaching a maximum in the >80 years group. CVI showed a significant negative correlation with age, and LCVL/SFCT showed a significant positive correlation with age. There was no statistically significant difference between males and females. Interrater and intrarater reliability was less variable with CVI than with SFCT.

CONCLUSIONS

The choroidal vascular area and CVI decreased with age in the healthy Chinese population, of which the age-related decrease in vascular components maybe dominated by the decrease in choriocapillaris and medium choroidal vessels. Sex had no effect on CVI. The CVI of healthy populations showed better consistency and reproducibility when compared with SFCT.

Association between macular and papillary vessel density by optical coherence tomography angiography in a large healthy population

PURPOSE

To provide a normative data set of the relationship between macular and papillary vessel density (VD) using swept-source optical coherence tomography angiography (SS-OCTA) in a large healthy population.

METHODS

Cross-sectional study conducted on 346 right eyes of healthy subjects. Macular and papillary SS-OCTA VD measurements of the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) in the central area and the four quadrants were obtained. Correlations between macular and papillary VD among different quadrants were assessed.

RESULTS

The mean participant age was 37.7 ± 19.8 years (range 5-83); 59% were women. No correlation was detected neither for the global SCP (R = 0.050; P = 0.040), DCP (R = -0.056; P = 0.038) nor CC (R = 0.102; P < 0.001) between macular and papillary VD. In a subanalysis, there was also no correlation in any of the quadrants studied (R ≤ 0.180; P < 0.001). In a subgroup of 45 left eyes, there was no correlation in the different plexus and layers studied between macular and papillary vasculature. No differences in SCP, DCP and CC were found according to gender, age or axial length in the relationship between macular and papillary VD.

CONCLUSION

There is no association between macular and papillary VD neither in the SCP, DCP or CC in any of the regions studied. Hence, macular and optic nerve head vascularization should be investigated separately to identify which structure is more relevant in each disease.

RELATIONSHIP BETWEEN MYOPIC CHOROIDAL NEOVASCULARIZATION ACTIVITY AND PERFORATING SCLERAL VESSELS IN HIGH MYOPIA

PURPOSE

To study perforating scleral vessels (PSVs) in patients with high myopia using swept-source optical coherence tomography and to determine their relationship with myopic choroidal neovascularization (mCNV) and its activity.

METHODS

Retrospective analysis of patients with high myopia (≥-6 D or ≥26 mm of axial length) using multimodal imaging. The presence of PSVs and mCNV was assessed using swept-source optical coherence tomography images (TRITON; Topcon Corporation, Japan).

RESULTS

Five hundred sixty-four eyes from 297 highly myopic patients were studied. One hundred fifty-five eyes (27.5%) showed signs of mCNV while PSVs were found in 500 eyes (88.6%). Perforating scleral vessels were found in 93.5% (145/155) of eyes with mCNV, and they were under or in contact with the mCNV in 80.6% (117/145). The mean number of intravitreal injections received by patients with mCNV was 4.06 ± 4.17 along 66.9 ± 4.1 months of follow-up. The number of injections per year was 1.32 ± 1.56, the mean number of relapses was 1.11 ± 1.83, and the mean number of relapses per year was 0.25 ± 0.41.

CONCLUSION

Perforating scleral vessels are more common among highly myopic patients suffering from neovascular complications. Myopic CNV complexes that are coincident with PSVs on optical coherence tomography show higher rates of activity, needing more injections to control them and being more prone to relapses.

Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

BACKGROUND

To investigate the symmetry of interocular choroidal thickness and vascularity index measurements in normal eyes using swept-source optical coherence tomography (SS-OCT). Cross-sectional and observational study. This study included 244 eyes of 122 normal adults with ages uniformly distributed from 19 to 89 years.

METHODS

SS-OCT imaging was performed using a scanning pattern of 12×12 mm. Mean choroidal thickness (MCT) and choroidal vascularity index (CVI) measurements in the entire scanning region were obtained using a validated and published automatic method. The correlation and differences (including signed and absolute differences) between bilateral MCT and CVI measurements were analyzed at the following 6 regions: 3 concentric circles centered on the fovea with diameters of 2.5, 5, and 11 mm; the inner rim from 2.5 to 5 mm circle; the outer rim from 5 to 11 mm circle; and the entire 12×12-mm scan region, respectively. Comparison of interocular MCT and CVI measurements.

RESULTS

MCT measurements in right and left eyes were strongly correlated in all regions [all intraclass correlation (ICC) >0.73], but MCT measurements in right eyes were significantly thicker than in left eyes. CVI measurements in right and left eyes were moderately correlated in all regions (all ICC >0.46), but CVI measurements in right eyes were significantly smaller than that in left eyes in the macular subregions (2.5 mm circle, 5 mm circle, and the inner rim). Neither signed nor absolute interocular differences in MCT were correlated with corresponding CVI interocular differences.

CONCLUSIONS

Choroidal differences exist between normal fellow eyes in adults in the absence of obvious pathology. This study is useful in assisting clinicians and researchers in distinguishing asymmetric changes that are to be expected in normal eyes versus changes that could be associated with diseases.

Choroidal Thickness Profile in Chorioretinal Diseases: Beyond the Macula

Enhanced depth imaging optical coherence tomography (EDI-OCT) and swept-source OCT (SS-OCT) have emerged as essential diagnostic tools in the study and management of various chorioretinal diseases. Evidence from early clinical studies using EDI-OCT and SS-OCT indicates that choroidal dysfunction plays a major role in the pathogenesis of chorioretinal diseases. Measurement of choroidal thickness (CT) has already become a major research and clinical method, and CT is considered as an indicator of choroidal status in a variety of ophthalmic diseases. Recently, CT measurement has also been proposed as a non-invasive marker for the early detection and monitoring of various systemic diseases. Among the several possible CT measurement locations, subfoveal CT has rapidly become a reliable parameter for measuring CT in healthy and diseased eyes. Moreover, recent advancements in OCT technology have enabled faster and wider imaging of the posterior part of the eye, allowing the various changes in CT as measured outside the macula to be shown accordingly. In this review, we first provide an overview of the results of clinical studies that have analyzed the healthy macular choroid and that in various chorioretinal diseases, and then summarize the current understanding of the choroid outside the macula. We also examine the CT profile as an index that encompasses both within and outside of the macula. Furthermore, we describe the clinical applications of ultrawide OCT, which enables visualization of the far periphery, and discuss the prospects for the development of more reliable choroidal parameters that can better reflect the choroid's characteristics.

Choroidal thickness changes in children with chronic heart failure due to dilated cardiomyopathy

PURPOSE

To evaluate choroidal thickness (CTh) in children with chronic heart failure (CHF) secondary to dilated cardiomyopathy (DCM) using spectral domain optical coherence tomography (SD-OCT) and to compare their values to those of healthy children.

METHODS

Sixty eyes of thirty children (mean age 9.9 ± 3.57 years) with chronic heart failure (left ventricular ejection fraction, LVEF ≤ 55%) due to DCM lasting for over 6 months were prospectively enrolled. The control group consisted of 30 age- (mean age 10.16 ± 3.42 years) and sex-matched healthy children. All participants underwent transthoracic echocardiography with LVEF measured using the Simpson method and had the blood serum level of N-terminal-pro-brain natriuretic peptide marker (NT-proBNP) determined. All children underwent SD-OCT and had subfoveal choroidal thickness (SFCTh) and CTh measured at 1500 µm (μm) nasally, temporally, superiorly and inferiorly from the fovea in both eyes by two investigators.

RESULTS

CTh at all locations was statistically significantly lower in children with DCM compared to the control group. Mean CTh in the group with CHF compared to the control group were (304.03 vs. 369.72 μm, p < 0.05) at the subfoveal location, (245.87 vs. 284 μm, p < 0.05) 1500 μm nasally from the fovea, (291.5 vs. 355.95 μm, p < 0.05) 1500 μm temporally from the fovea, (303.98 vs. 357.58 μm, p < 0.05) 1500 μm superiorly from the fovea and (290.92 vs. 344.96 μm, p < 0.05) 1500 μm inferiorly from the fovea. The average difference CTh between the study groups ranged from 38.13 to 65.69 μm at individual locations. In both groups, CTh was the thickest at subfoveal location (304.03 vs. 369.72 μm, p < 0.05) and the thinnest was 1500 μm nasally from the fovea (262.37 vs. 336.87 μm, p < 0.05). There was no correlation between CTh and age, gender, biometry and refractive error. No correlation was found between CTh and LVEF and NT-proBNP.

CONCLUSION

Patients with CHF due to DCM had a thinner CTh at all measured locations. The results of our research indicate that CHF affects CTh and this parameter may be very helpful in monitoring the clinical course of the disease in children with DCM.

Wide-Field Swept-Source Optical Coherence Tomography Analysis of Interocular Symmetry of Choroidal Thickness in Healthy Young Individuals

Purpose

The purpose of this paper was to study the bilateral choroidal thickness (CT) symmetry and differences in healthy individuals using wide-field swept-source optical coherence tomography (SS-OCT).

Methods

All participants underwent a wide-field 16-mm 1-line scan using SS-OCT. CTs were measured at the following 12 points: 3 points at 900 µm, 1800 µm, and 2700 µm away from the nasal optic disc margin (nasal peripapillary area), 1 point at the subfovea, 6 points at 900 µm, 1800 µm, and 2700 µm away from the subfovea to the nasal and temporal areas (macular area), and 2 peripheral points at 2700 and 5400 µm from temporal point 3 (peripheral area). Bilateral CTs were measured; their correlations and differences in the corresponding regions were analyzed.

Results

There were no statistically significant differences in CTs between the right and left eyes in all corresponding areas (all P > 0.05); they all showed significant positive correlation coefficients (r) (all P < 0.001). However, the nasal peripapillary and peripheral areas had relatively low correlation coefficients, compared to the macular areas. In addition, the bilateral CT differences were 32.60 ± 25.80 µm in the macular area, 40.67 ± 30.58 µm in the nasal peripapillary area, and 56.03 ± 45.73 µm in the peripheral area (all P < 0.001).

Conclusions

Overall, the CTs of each region were bilaterally symmetrical. However, the differences in CTs increased from the center to the periphery, which indicated that the anatomic variation of the nasal peripapillary and peripheral choroid was greater than that of the macula.

Choroidal Thickness Profile in Normal Iranian Eyes with Different Refractive Status by Spectral-Domain Optical Coherence Tomography

Purpose

To investigate the choroidal thickness and its association with age, gender, spherical equivalent (SE), and axial length (AL) in a sample of Iranian population with different refractive status using spectral-domain optical coherence tomography (SD-OCT).

Methods

In a cross-sectional study, a total of 469 right eyes of 469 healthy subjects comprising 194 (41.4%) males and 275 (58.6%) females were examined. The mean age was 32.76 ± 15.77 years (range, 4-60 years). All subjects were divided into different groups according to their refractive status, age, and AL. The choroidal thickness was evaluated through enhanced-depth imaging (EDI) modality at subfoveal (Sf), 1, and 3 mm nasal (N1 and N3, respectively), temporal (T1 and T3, respectively), superior (S1 and S3, respectively), and inferior (I1 and I3, respectively) to the foveal center.

Results

In the whole population, the mean subfoveal choroidal thickness (SfChT) was 329.83 ± 70.33 μm, and the choroid was thickest at S1 (342.04 ± 71.28 μm) and thinnest at N3 (209.00 ± 66.0 μm). Our data indicated a significant difference in the mean choroidal thickness across all points in different age groups (P < 0.0001). For emmetropic, myopic, and hyperopic subjects, mean SfChT values were 346.64 ± 59.63, 319.66 ± 73.17, and 364.00 ± 74.54 μm, respectively. Linear regression estimated that SfChT decreased about 12.8 and 8.71 μm for every 10 years of aging and each diopter increasing in myopia, respectively. Additionally, the SfChT decreased as 13.48 μm per mm increase in AL.

Conclusions

The mean SfChT of a sample of Iranian emmetropic subjects was 346.64 ± 59.63 μm. The choroidal thickness has a decreasing trend with increasing age, and the choroid is thinner in myopes and thicker in hyperopes compared with emmetropic subjects. In the whole participants, the thickest and thinnest points were S1 and N3, respectively.

Analysis of Choroidal Vascularity Index in Keratoconus Patients Using Swept-Source Optical Coherence Tomography-Based Binarization Techniques

Purpose

To analyse the vascular density of the choroid in a keratoconus (KC) population using swept-source optical coherence tomography (SS-OCT).

Methods

Prospective, noninterventional study that analysed 97 eyes from 52 KC patients and 145 eyes from 89 healthy controls. The sample was divided in four different age groups. Inclusion criteria were topographic diagnosis of KC using Pentacam, axial length shorter than 26 mm, good quality of the images, and no other systemic or ocular diseases. A 12 mm horizontal single-line SS-OCT b-scan was performed to create a choroidal thickness (CT) profile. Validated automated segmentation and binarization were used in order to analyse choroidal, stromal, and vascular areas.

Results

The percentage of choroidal vascularity (vascular area/total area) was 56.6% in KC patients vs. 49.4% in controls. Aged-adjusted choroidal, stromal, and vascular areas and corrected choroidal percentage of vascularity are statistically increased in KC patients when compared with healthy controls (p < 0.001). All these parameters show a decreasing trend with age. Both stromal and vascular areas were thicker in KC patients (p < 0.001).

Conclusions

Choroidal, stromal, and vascular areas and corrected choroidal percentage of vascularity are statistically increased in KC patients when compared with healthy controls. All these parameters tend to decrease with age.

Choroidal vascular changes in internal carotid artery stenosis: a retrospective cohort study in Chinese population

Background

To evaluate choroidal vascularity index (CVI) in eyes with internal carotid artery (ICA) stenosis using binarization tool in enhanced depth images scanned by spectral domain optical coherence tomography.

Methods

A retrospective cohort study was conducted in 142 patients with ICA stenosis, and 20 normal control subjects matched with the age, sex, etc. According to the diagnostic criteria, the participants are divided into a normal control group (20 cases), a mild stenosis group (64 cases), a moderate stenosis group (61 cases), and a severe stenosis group (17 cases). Enhanced depth imaging optical coherence tomography (EDIOCT) was performed to scan macular fovea, which was separated into a luminal area and a stromal area using image binarization. The choroidal vascularity index (CVI) is luminal area divided by total choroidal area.

Results

There was no statistical difference in age or sex among groups. Subfoveal choroidal thickness (SFCT) in the severe stenosis group was significantly lower than that in the normal group (P < 0.05). Moreover, the CVI in moderate stenosis group and severe stenosis group were significantly lower compared with the normal control group (P < 0.001). When CVI = 65.16% was set as the cut-off value, all 162 subjects could be divided into two groups, CVI ≤ 65.16 (n = 83) and CVI > 65.16% (n = 79). The proportions of mild stenosis, moderate stenosis, and severe stenosis in CVI ≤ 65 .16 group and CVI > 65.16% group were statistically significant (P < 0.001).

Conclusion

CVI may be a useful indicator for early diagnosis and monitoring of choroidal vascular changes in ICA stenosis.

Normative database and determinants of macular vessel density measured by optical coherence tomography angiography

IMPORTANCE

To provide a normative vessel density (VD) database for the macula through swept-source optical coherence tomography angiography (OCTA) and to assess the main determinants of this measurement.

BACKGROUND

In contrast with dye angiography, the recently introduced OCTA technique allows for the non-invasive measurement of retinal and choroidal VD metrics.

DESIGN

Cross-sectional study.

PARTICIPANTS

The right eyes of 346 healthy subjects were studied. In 105 subjects both eyes were imaged.

METHODS

Foveal and parafoveal macular VD measurements were obtained in the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and in the choriocapillaris (CC) layer. Also recorded were age, sex, axial length (AL), foveal and choroidal thickness (CT).

MAIN OUTCOME MEASURES

Normative database and determinants of macular VD measured by OCTA.

RESULTS

Mean participant age was 38.3 ± 20.1 years (mean ± SD) (range 5-83). Foveal VDs in the different plexuses were: SCP 22.1% ± 5.0% (7.3-35.1), DCP 19.9% ± 6.3% (6.9-51.2) and CC: 52.8% ± 4.3% (40.2-62.1). Parafoveal VDs ranged from 45.4% ± 3.7% to 51.8% ± 4.6%. Positive correlation was observed between foveal VD and foveal thickness (R = .327), as well as between parafoveal DCP VD and CT (R = .250;P ≤ .006), while correlation with age was negative in the SCP and CC (R = -.283;P < .001). No associations were detected between macular VD and sex or AL (P ≥ .05).

CONCLUSION AND RELEVANCE

Macular VD showed wide individual variation, was positively correlated with foveal thickness and with CT, negatively correlated with age, and showed no correlation with AL or sex.

Foveal and parafoveal choroidal thickness pattern measuring by swept source optical coherence tomography

OBJECTIVE

To evaluate the choroidal thickness (CT) in foveal and parafoveal regions in Thai adults using swept-source optical coherence tomography (SS-OCT).

METHODS

We enrolled healthy volunteers ≥18 years of age from King Chulalongkorn Memorial Hospital, Thailand, during September 2015 to March 2016. Optical coherence tomography (OCT) of the macula was performed, and subfoveal CT was measured manually using a line scan. Average thicknesses of retinal and choroidal layers in regions of the Early Treatment Diabetic Retinopathy Study grid were measured automatically. A multivariate analysis was conducted to determine correlations between CTs in the foveal and parafoveal regions and retinal layers.

RESULTS

Altogether, 144 eyes from 144 subjects (29 men, 115 women; mean age 41 years) were studied. The mean foveal CT was 282.4 ± 13.8 µm. It was thicker in the temporal fovea than in the nasal fovea (p < 0.001) and thicker in men than in women. Multivariate analysis showed that age and sex were significantly negatively correlated with the thickness of the retina, ganglion cell layer, outer retinal layer, and choroid but not of the nerve fiber layer. Regression analysis revealed that the CT decreased approximately 1.5 μm per year.

CONCLUSIONS

Age and sex significantly influence choroidal thickness. Macular CT in a healthy eye thins with age. CT decreases with age faster at distances away from the foveal center than at the center. Subfoveal CT was greater than the mean CT. Parafoveal CT should be evaluated to identify specific retinal-choroidal disease.

Novel Classification of Early-stage Systemic Hypertensive Changes in Human Retina Based on OCTA Measurement of Choriocapillaris

The traditional classification of hypertensive retinopathy was based on the Keith-Wagener-Barker (KWB) grading, which is a subjective scaling system, and it is difficult to distinguish between the first and second grades. Retinal and choroidal vasculatures are affected by systemic hypertension, although retinal vasculature changes with age, axial length, intraocular pressure, and retinal diseases. It is necessary to establish a new objective method to assess hypertensive vascular changes. In the present study, we have examined the vasculature of the macular choriocapillaris in order to establish a new objective method to assess hypertensive vascular changes using optical coherence tomography angiography (OCTA). Choriocapillaris vessel density (VD), vessel length, and vessel diameter index in a 3 × 3 mm macular area were measured by OTCA in a total of 567 volunteers (361 healthy subjects and 206 subjects with systemic hypertension) who attended a basic health check-up. Ocular factors, systemic factors, and medications were evaluated. We detected significant differences in normative choriocapillaris vasculature between the left and right eyes in 53 healthy subjects and revealed correlations between age, intraocular pressure, axial length, and choriocapillaris vasculature in 308 healthy subjects. Normative foveal VD was correlated with age only and the efficiency was weak. The analysis of 206 right eyes (KWB grade 0, 159 eyes; grade 1, 35 eyes; and grade 2, 12 eyes) revealed that foveal VD was strongly correlated with KWB grade only (P < 0.001). This is the first report suggesting that OCTA for foveal choriocapillaris measurement by OCTA would might provide the advantage of evaluating be objective method for evaluating the progression of systemic hypertension.

Macular Choroidal Thickening in Keratoconus Patients: Swept-Source Optical Coherence Tomography Study

Purpose

To determine the choroidal thickness (CT) profile in keratoconus (KC) patients using swept-source optical coherence tomography (SS-OCT).

Methods

This was a prospective, cross-sectional study. One hundred two eyes of 52 KC patients were studied using Pentacam and SS-OCT. The macular CT profile was created by manually measuring the distance between the retinal pigment epithelium and the choroid-sclera junction on horizontal b-scans at nine different macular locations. The results were compared to 93 eyes of 93 healthy controls.

Results

Mean age of the KC group was 34.9 ± 13.5 years and mean axial length (AL) was 24.1 ± 1.3 mm. Mean topographic KC classification (TKC) was 2.0; 39 eyes were classified as early KC (TKC <1–2), 34 eyes as moderate (TKC 2, 2–3), and 29 as advanced (TKC 3+). Mean subfoveal CT was 383.2 μm in KC patients and 280.5 μm in control group (P < 0.001). CT in KC patients was statistically thicker in all measure locations (P < 0.001). CT in KC eyes decreased with age, approaching control group at >45 years old, losing statistical significance (P = 0.37).

Conclusions

CT in KC patients is statistically thicker than in healthy population. After age 45, CT decreases approaching control group values.

Translational Relevance

This study describes changes in the CT profile of KC patients, a disease that was considered purely corneal. These choroidal changes argue that KC is a disease that likely involves several ocular structures other than the cornea, and could open new research lines related to the pathophysiology of KC.

AGE-RELATED CHANGES IN CHOROIDAL VASCULAR DENSITY OF HEALTHY SUBJECTS BASED ON IMAGE BINARIZATION OF SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

To analyze the vascular density of the choroid in a healthy population using swept-source optical coherence tomography.

METHODS

A cross-sectional, noninterventional study.

INCLUSION CRITERIA

best-corrected visual acuity between 20/20 and 20/25, spherical equivalent between ±3 diopters, no systemic or ocular diseases, and ages ranging between 3 and 85 years. One hundred and thirty-six eyes from 136 subjects were analyzed, 86 eyes (63.2%) were from male and 50 eyes (36.8%) from female subjects. The eyes were divided into different age groups to analyze the possible age-related changes. Twelve-millimeter horizontal, fovea-centered B-scans were used. Choroidal stroma and vessel area analysis involved automated segmentation and binarization using validated algorithms.

RESULTS

Mean age was 33.1 ± 24.5 years. Mean choroidal area was 0.5554 ± 0.1377 mm. Mean stromal area was 0.2524 ± 0.0762 mm, and mean vascular region area was 0.3029 ± 0.0893 mm. The percentage of choroidal vascularity (vascular area/total area) was 54.40 ± 8.35%. Choroid area, vascular region, and percentage of choroidal vascular density were statistically higher in the <18-year-old group versus the >18-year-old group (P < 0.001). The stromal region was not different (P = 0.46). In the same way, choroid area, vascular region, and percentage of choroidal vascular density between the 5 age groups were statistically different (P < 0.001), showing larger figures in the 0 to 10-year-old group, but not stromal region (P = 0.71). There were no gender-related differences.

CONCLUSION

The luminal area and the percentage of vascular/total area decrease with increasing age, while the stromal area remains stable.

Update of choroidal imaging techniques: Past, present and future

The choroid is the middle layer of the eye, a very vascular and pigmented tissue, with its role in several ophthalmological pathologies already having been clearly established. But it was not until the last few years that we have been able to reliably and precisely measure and quantify its shape and thickness. Ultrasound technology and indocyanine green angiography were the first techniques used for the study of the choroid, and they still maintain their use and clinical indications for the diagnosis and management of several pathologies. But it was the advent of optical coherence tomography that was the greatest breakthrough in choroidal imaging. In this chapter, the past, current and future image modalities for the study of the choroid will be discussed, with special focus on optical coherence tomography and its latest developments.

Interocular symmetry of the peripapillary choroidal thickness and retinal nerve fibre layer thickness in healthy adults with isometropia

Background

The aim of this study was to determine the interocular differences in the peripapillary retinal nerve fibre layer (RNFL), peripapillary choroidal thickness (PCT) and subfoveal choroidal thickness (SFCT) in healthy adults with isometropia, using enhanced depth imaging optical coherence tomography (EDI SD-OCT).

Methods

One hundred healthy Chinese adults with spherical equivalents of ≤ ±3 dioptres and interocular differences of <0.5 dioptres were prospectively enrolled in this study. They underwent RNFL and PCT measurements via EDI SD-OCT, with a 3.4 mm scan circle centred on the optic nerve head. Subfoveal choroidal thickness (SFCT) measurements were also taken with a horizontal line scan centred on the macula. Right and left eyes were compared by a paired t-test, and the interocular differences were calculated. The agreement and correlations of the RNFLs, PCTs and SFCTs between the right and left eyes were analysed.

Results

Eighty-six subjects (172 eyes) were included in the final analysis, consisting of 44 (51.6 %) males and 42 (48.8 %) females; 55 (63.9 %) had emmetropia and 33 (36.1 %) had ametropia. The RNFL was statistically significantly thicker in the right eyes when compared to the left eyes in the temporal quadrant, and thinner on average in the nasal superior quadrant (p < 0.05). However, the differences in the choroidal thicknesses in all of the quadrants between the right and left eyes were not statistically significant. The tolerance limits of the average RNFL were −21.1 μm and 7.1 μm, and the mean and standard deviation of the interocular difference in the average PCT was −2.2 ± 24.2 μm. The RNFLs and PCTs in all of the locations in the right eyes were significantly correlated with those in the left eyes. However, no significant associations between the age, sex, interocular asymmetry of spherical the equivalent or interocular differences in the RNFL and PCT were detected.

Conclusion

The PCT did not differ significantly between the right and left eyes, although interocular asymmetry of the RNFL existed in this Chinese population with isometropia.

Retinal and Choroidal Thicknesses Measured with Swept-Source Optical Coherence Tomography after Surgery for Idiopathic Macular Hole

Purpose

To evaluate the changes in retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness (GCLT), retinal thickness (RT), and subfoveal choroidal thickness (SFCT) in eyes that received pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for idiopathic macular hole (IMH) and to compare these data with data from fellow eyes and healthy controls.

Methods

This cross-sectional study included 49 subjects. Eighteen eyes that underwent surgery for IMH, 18 fellow eyes, and 31 eyes of the healthy controls were designated as group 1, group 2, and group 3, respectively. The RNFLT, GCLT, RT, and SFCT were measured by using the swept-source optical coherence tomography (SS-OCT) device at last postoperative visit.

Results

The RNFLT was significantly lower in group 1 than group 2 and group 3 (p<0.05). The GCLT was significantly reduced in all sectors in group 1 as compared to group 2 and group 3 (p<0.05). The RT was found to be significantly lower (except in central field) in group 1 than group 2 and group 3 (p<0.05). The SFCT was significantly decreased in group 1 as compared to group 2 and group 3 (p<0.05).

Conclusions

A reduction in the RNFLT, GCLT, RT, and SFCT was observed following PPV with ILM peeling for IMH detected by SS-OCT.

Choroidal thickness in non-neovascular versus neovascular age-related macular degeneration: a fellow eye comparative study

PURPOSE

To investigate the possible differences in choroidal thickness (CT) between non-neovascular (NNV) and neovascular (NV) age-related macular degeneration (AMD).

METHODS

A retrospective, observational chart review of consecutive patients diagnosed with NNV AMD in one eye and with NV AMD in the fellow eye was carried out. NNV AMD was classified into four subgroups according to the Beckman Initiative for Macular Research AMD Classification Committee Meeting. CT was manually assessed using enhanced depth imaging optical coherence tomography from 1500 µm nasal to 1500 µm temporal to the fovea. Parametric and non-parametric tests were used to compare quantitative variables, a χ² test was used to compare categorical variables and logistic regression was used to evaluate associations of CT with other variables of interest.

RESULTS

In this study, 322 eyes from 161 patients were included and 102 (63.35%) were female and 59 (36.65%) were male, with a mean age of 80.80±8.45 years (range 58-99 years). Mean follow-up was 11.2±10.8 months (range 1-38 months). In NNV AMD eyes, the choroid was significantly thicker in the subfoveal and temporal regions of the macula, if compared with NV AMD fellow eyes. Differences in CT between NNV AMD and NV AMD fellow eyes were higher at earlier stages of NNV AMD.

CONCLUSIONS

Subfoveal and temporal choroid was significantly thicker in NNV AMD compared with NV AMD fellow eyes. There was a significant choroidal thinning at advanced stages of NNV AMD.

Morphologic features of the choroidoscleral interface in a healthy population using swept-source optical coherence tomography

OBJECTIVE

To analyze the morphologic features of the choroidoscleral interface in a healthy population using swept-source optical coherence tomography (SS OCT).

DESIGN

Retrospective data analysis of a subgroup of eyes from a previous single-center, prospective, cross-sectional, noninterventional study.

METHODS

A total of 276 healthy eyes from 154 subjects were evaluated using SS OCT. Inclusion criteria were best-corrected visual acuity between 20/20 and 20/25, spherical equivalent between ±3 diopters, and no systemic or ocular diseases. Two independent investigators analyzed the morphologic features of the choroidoscleral interface in a masked fashion, classifying the contour and shape as concave (bowl-shaped) or inflective (S-shaped contour with ≥1 inflection point).

RESULTS

The presence of a temporal choroidoscleral interface inflection was identified in 12.8% of the eyes. The mean choroidal thickness was 372.1 ± 76.8 μm and the average distance from the inflection point to the fovea was 4427.3 ± 627.9 μm. Nine patients showed an inflective profile in both eyes. No changes in the retinal profile were found in any of these cases. The mean age of the patients with an inflective profile was 16 ± 19 years (range 4-82) vs 36 ± 25 years (range 3-95) in the group with a concave contour (P = .001). The temporal choroidal thickness at 4000 and 5000 μm from the fovea was thicker in the group with a concave contour.

CONCLUSIONS

Temporal choroidoscleral interface inflection or S-shaped profile of the choroidoscleral interface with focal thinning of the choroid can be considered a normal variation without clinical significance, especially in younger populations.