Influence of Aberration-Free, Narrowband Light on the Choroidal Thickness and Eye Length.

Purpose: To determine whether light chromaticity without defocus induced by longitudinal chromatic aberration (LCA) is sufficient to regulate eye growth. Methods: An interferometric setup based on a spatial light modulator was used to illuminate the dominant eyes of 23 participants for 30 minutes with three aberration-free stimulation conditions: (1) short wavelength (450 nm), (2) long wavelength (638 nm), and (3) broadband light (450-700 nm), covering a retinal area of 12°. The non-dominant eye was occluded and remained as the control eye. Axial length and choroidal thickness were measured before and after the illumination period. Results: Axial length increased significantly from baseline for short-wavelength (P < 0.01, 7.4 ± 2.2 µm) and long-wavelength (P = 0.01, 4.8 ± 1.7 µm) light. The broadband condition also showed an increase in axial length with no significance (P = 0.08, 5.1 ± 3.5 µm). The choroidal thickness significantly decreased in the case of long-wavelength light (P < 0.01, -5.7 ± 2.2 µm), but there was no significant change after short-wavelength and broadband illumination. The axial length and choroidal thickness did not differ significantly between the test and control eyes or between the illumination conditions (all P > 0.05). Also, the illuminated versus non-illuminated choroidal zone did not show a significant difference (all P > 0.05). Conclusions: All stimulation conditions with short- and long-wavelength light and broadband light led to axial elongation and choroidal thinning. Therefore, light chromaticity without defocus induced by LCA is suggested to be insufficient to regulate eye growth. Translational Relevance: This study helps in understanding if light chromaticity alone is a sufficient regulator of eye growth.

El espacio supracoroideo en pacientes afectados por retinosis pigmentaria / The suprachoroidal space in patients affected by retinitis pigmentosa

Antecedentes y objetivo: El espacio supracoroideo (SCS) es una estructura teórica que se sitúa entre el borde interno de la esclera y el límite externo del coroides. El SCS está siendo estudiado por sus posibles usos como vía para la administración de medicamentos y por técnicas quirúrgicas innovadoras para el tratamiento de muchas enfermedades retinianas. La retinitis pigmentosa (RP) es un grupo de trastornos hereditarios y progresivos caracterizados por el detrimento gradual de fotorreceptores que conduce a una discapacidad visual que se manifiesta típicamente como hemeralopía y pérdida progresiva del campo visual. El objetivo del estudio fue definir la morfología de los márgenes coroideos externos mediante el uso de tomografía de coherencia óptica de barrido (SS-OCT) en la RP.Materiales y métodosEstudio observacional retrospectivo diseñado para evaluar la presencia del ESC en la RP. Realizamos SS-OCT en un grupo de 55 pacientes afectados por RP (26 hombres y 29 mujeres, 110 ojos) con una edad media de 51,8±13,7 años. En el grupo de control incluimos a 28 sujetos sanos (6 hombres y 22 mujeres, 56 ojos) con una edad media de 48,8±16,6 años.ResultadosLas imágenes OCT permitieron delinear de manera precisa el margen coroideo externo y el margen escleral interno en los 110 ojos. En el grupo RP se detectó el ESC en 47 de los 110 ojos (42,7%), en el grupo de control se detectó el ESC en 11 ojos (19,6%).Los sujetos del grupo RP con SCS visibles presentaron un menor grosor retiniano (168,4 micrones) en comparación con aquellos con SCS visibles (211,2 micrones, p=0,007). (AU)

Background and objective: The suprachoroidal space (SCS) is a theoretical structure which can be demonstrated between the inner border of the sclera and the outer boundary of the choroid. SCS is being studied for its potential uses as a route for drug delivery and innovative surgical techniques for the treatment of many retinal diseases. Retinitis pigmentosa (RP) is a group of inherited eye disorders characterized by a gradual loss of photoreceptors, resulting in vision impairment, which typically presents as night blindness and progressive visual field loss. The purpose of the study is to define the morphology of outer choroidal margins by means of SS-OCT in RP.Material and methodThis is a retrospective observational study designed to evaluate the presence of SCS in RP. We performed swept source optical coherence tomography (SS-OCT) in a group of 55 patients affected by RP (26 males and 29 females, 110 eyes) with a mean age of 51.8±13.7 years. In the control group, we included 28 healthy subjects (6 males and 22 females, 56 eyes) with a mean age of 48.8±16.6 years.ResultsOCT scans allowed the outer choroidal margin and inner scleral margin to be delineated with certainty in all 110 eyes. In the RP group SCS was detected in 47 of 110 eyes (42.7%), in the control group SCS was detected in 11 eyes (19.6%).Subjects with SCS visible (RP group) had reduced retinal thickness (168.4μm) compared to those with not visible SCS (211.2μm, p=0.007). (AU)

Assessment of macular choroidal and retinal thickness: a cohort study in Tibetan healthy children.

This research investigates the distribution, progressive changes, and contributing factors of macular choroidal and retinal thickness in Tibetan children utilizing swept-source optical coherence tomography (SS-OCT). The Lhasa childhood study recruited 1632 students from seven primary schools in Lhasa. These participants underwent OCT and ophthalmological evaluations, encompassing retinal and choroidal thickness measurements, refractive error, axial length (AL), and systemic examinations. The median age of the scholars was 8.57 ± 0.50 years with a median spherical equivalent (SE) of 0.19 ± 1.28D. Multivariate regression analysis revealed that thinner macular choroid thickness was correlated with lower value of SE, worse best-corrected visual acuity, higher mean arterial blood pressure (MABP) and boys, while retinal thickness was associated with better image quality and lower value of SE. The choroid and retina were significantly thinner in myopic children. SE was positively related to the thickness of all choroidal and full retinal subregions. In comparison to baseline data from 20 months prior, most regions of the full retina had significantly thinned. Choroidal thickness of Tibetan children is thinner than that of same-age children from other regions. Thinning of retina, the outer-sector GCC and GCIPL may be specified as a follow-up and prognostic indicator for myopia.

The suprachoroidal space in patients affected by retinitis pigmentosa.

BACKGROUND AND OBJECTIVE: The Suprachoroidal Space (SCS) is a theoretical structure which can be demonstrated between the inner border of the sclera and the outer boundary of the choroid. SCS is being studied for its potential uses as a route for drug delivery and innovative surgical techniques for the treatment of many retinal diseases. Retinitis pigmentosa (RP) is a group of inherited eye disorders characterized by a gradual loss of photoreceptors, resulting in vision impairment, which typically presents as night blindness and progressive visual field loss. The purpose of the study is to define the morphology of outer choroidal margins by means of SS-OCT in RP. MATERIAL AND METHOD: This is a retrospective observational study designed to evaluate the presence of SCS in RP. We performed Swept Source optical coherence tomography (SS-OCT) in a group of 55 patients affected by RP (26 males and 29 females, 110 eyes) with a mean age of 51.8 ±â€¯13.7 years. In the control group, we included 28 healthy subjects (6 males and 22 females, 56 eyes) with a mean age of 48,8 ±â€¯16,6 years. RESULTS: OCT scans allowed the outer choroidal margin and inner scleral margin to be delineated with certainty in all 110 eyes. In the RP group SCS was detected in 47 of 110 eyes (42,7%), in the control group SCS was detected in 11 eyes (19,6%). Subjects with SCS visible (RP group) had reduced retinal thickness (168.4 µm) compared to those with not visible SCL (211.2 µm, P = .007). CONCLUSIONS: SS-OCT can be successfully applied to assess the presence of SCS in RP and the high rate of SCS found in the RP patients is encouraging when considering future innovative therapies.

Relación entre grosor coroideo y densidad vascular en población joven sana / Relationship between choroidal thickness and vascular density in young healthy population

Antecedentes y objetivo El objetivo es analizar la densidad vascular (DV) coroidea en individuos sanos y compararla con el grosor coroideo (GC). Materiales y métodos Estudio transversal incluyendo individuos entre 18 y 35 años, caucásicos y con longitud axial (LA) 21-26 mm. Se estudió la coroides con tomografía de coherencia óptica-angiografía (OCTA) Triton DRI (Topcon) y se obtuvo un cubo macular de 6x6 mm. El software dio los valores de GC automáticamente. Los valores de DV se obtuvieron mediante codificación en números de los colores de los mapas de DV. Resultados Se analizaron 102 ojos (51 pacientes). La edad media fue 27,32 ± 3,94 años, la presión intraocular media fue 18,07 ± 2,38 mmHg, y la LA media fue 23,71 ± 0,66 mm. El GC fue mayor en el eje vertical y menor al acercarse a los lados nasal y temporal. El mayor GC se encontró en la mácula superior. La mayor DV coroidea fue en la fóvea y en la región yuxtapapilar. La menor DV coroidea se halló en la mácula superior e inferior. Se encontraron correlaciones moderadas inversas entre GC y DV coroidea en las regiones yuxtapapilar e inferior. Conclusiones La coroides tiene un patrón de grosor diferente del de la retina. Los vasos coroideos representan un porcentaje muy alto de la coroides en las regiones peripapilar y fóvea. Por el contrario, la mácula superior e inferior muestra valores bajos de DV (AU)

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 mm × 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 One hundred and two (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 (AU)

Choroidal thickness assessment in keratoconus patients treated with cross-linking compared to healthy population.

PURPOSE: To analyze the choroidal thickness between patients with keratoconus undergoing cross-linking treatment and a healthy population, as well as to determine the factors that influence choroidal thickness. METHODS: This was an observational, analytical, case-control study that was conducted from February 2021 to June 2021. Choroidal thickness was measured at different locations, including the subfoveal, nasal (1000 µm), temporal (1000 µm), superior (1000 µm) and inferior (1000 µm) locations using a Spectral-domain optical coherence tomography with enhanced depth imaging, which allowed us to obtain horizontal and vertical B-scans centered on the fovea. RESULTS: This study included 21 patients with keratoconus (mean age, 21.86 ± 5.28 years) and 28 healthy patients (mean age, 24.21 ± 4.71 years). Choroidal thickness was significantly greater in patients with keratoconus than in healthy patients in each of the following measured locations: subfoveal (P < 0.001); nasal (1000 µm) (P < 0.001), temporal (1000 µm) (P < 0.001), superior (1000 µm) (P < 0.001) and inferior (1000 µm) (P < 0.001) locations. Variables such as age (ρ = - 0.09; P = 0.50) and refraction (ρ = 0.14; P = 0.34) were not found to be associated with choroidal thickness. In a stepwise multiple linear regression, the group was the single variable correlated with choroidal thickness (ß = 0.88; P < 0.001). CONCLUSION: Choroidal thickness is thicker in keratoconus patients treated with cross-linking than in the healthy population. This finding could be associated with inflammatory choroidal mechanisms in keratoconus patients, but more studies are needed. Age and refractive error do not seem to influence choroidal thickness.

Vascular Choroidal Alterations in Uncomplicated Third-Trimester Pregnancy.

(1) Purpose: To evaluate the anatomy and perfusion of choroidal substructures in third-trimester pregnant women using optical coherence tomography (OCT) and OCT angiography (OCTA) imaging. (2) Methods: In this cross-sectional study, women in their third trimester of uncomplicated pregnancy and non-pregnant age-matched women were recruited. Participants underwent enhanced depth imaging (EDI) OCT and OCTA. Subfoveal choroidal thickness (SFCT), as well as choroidal sublayer perfusion, were compared between groups. (3) Results: In total, 26 eyes of 26 pregnant and 26 eyes of 26 non-pregnant women were included. The median age in both groups was 29 years. The median SFCT was 332 (211-469) µm in the pregnant group and 371.5 (224-466) µm in the non-pregnant cohort (p = 0.018). The median choriocapillaris perfusion (CCP) was significantly lower in the pregnant group (46% vs. 48%, p = 0.039). Moreover, Haller's layer perfusion correlated significantly with mean arterial pressure in non-pregnant women (CC = 0.430, p = 0.028) but not in pregnant ones (CC = 0.054, p = 0.792). (4) Conclusions: SFCT was found to be thinner and CCP was lower in third-trimester pregnant women. Hormonal changes during pregnancy and consecutive impacts on autoregulation of small choroidal vessels might play an important role. Therefore, altered choroidal measurements during third-trimester pregnancy should be carefully evaluated as, to some extent, it could be a normal physiological change.

Choroidal Thickening During Young Adulthood and Baseline Choroidal Thickness Predicts Refractive Error Change.

Purpose: The purpose of this study was to explore the age-related change in choroidal thickness (ChT) and test the hypothesis that baseline ChT is predictive of refractive error change in healthy young adults. Methods: Participants underwent spectral-domain optical coherence tomography (SD-OCT) imaging and autorefraction at 20 (baseline) and 28 years old. The enhanced depth imaging mode on the SD-OCT was used to obtain images of the choroid. Scans were exported from the SD-OCT and analyzed with a custom software that automatically measures the central ChT. The longitudinal change in subfoveal ChT and association between baseline subfoveal ChT and 8-year change in refractive error (spherical equivalent) were determined using linear mixed models. Results: In total, 395 eyes of 198 participants (44% men; 18-22 years at baseline) were included. Over 8 years, mean spherical equivalent decreased by 0.25 diopters (D) and axial length increased by 0.09 mm. Subfoveal choroid thickened by 1.3 µm/year (95% confidence interval [CI] = 0.6-2.0), but this was reduced by 0.9 µm/year (95% CI = 1.6-0.2) for every 1 mm increase in axial length. For every 10 µm increase in baseline ChT, average annual change in spherical equivalent and axial length reduced by 0.006 D/year and 0.003 mm/year, respectively. Conclusions: In a community-based cohort of young adults, the choroid continued to change during early adulthood. Choroidal thickening was less in eyes that were longer at baseline, and the choroid thinned in eyes that showed myopia progression. The association between baseline ChT and longitudinal changes in spherical equivalent and axial length supports the hypothesis that ChT may be predictive of refractive error development and/or myopia progression.

Relationship of choroidal thickness and axial length with posterior vitreous detachment in patients with high myopia.

Although accumulating evidence suggests a higher prevalence of posterior vitreous detachment (PVD) in highly myopic eyes, the relation between ocular biometric features and PVD stages in such eyes remains unclear. Therefore, we enrolled 170 patients with high myopia (axial length ≥ 26.0 mm) to investigate the status of PVD regarding subfoveal choroidal thickness and axial length. Utilising swept-source optical coherence tomography, we classified the PVD status into five stages. The distribution of PVD grades increased as the choroidal thickness decreased and axial length increased (P < 0.01). On adjusting for age and sex, decreased choroidal thickness and increased axial length were associated with more advanced PVD stages: odds ratios with the highest vs. lowest groups were 0.31 (95% confidence interval [CI] 0.09-1.01; Ptrend = 0.009) for choroidal thickness and 5.16 (95% CI 1.34-19.80; Ptrend = 0.002) for axial length. The inverse association between choroidal thickness and PVD status seemed stronger in women than in men (Pinteraction = 0.05). In conclusion, we firstly observed a significant trend of decreased choroidal thickness, along with increased axial length, with increased grade of PVD, particularly among women with highly myopic eyes, suggesting that advanced morphological myopic changes contribute to PVD in middle-aged adults.

Choroidal Thickness Measured by Ocular Coherence Tomography (SD-OCT) and Body Mass Index in Healthy Saudi Women: A Cross-sectional Controlled Study.

BACKGROUND: Obesity is one of the major public health problems globally, especially among women. Obesity is associated with glaucoma, cataract, age-related macular degeneration and diabetic retinopathy. Although it is clear that the anatomy and physiologic functions of the choroid may be affected by obesity, data investigating the effect of obesity on the choroid is limited and/or unavailable for the Saudi population. OBJECTIVE: To assess Choroidal Thickness (CT) changes in a sample of healthy Saudi Arabian women with different Body Mass Index (BMI) using Spectral-domain Ocular Coherence Tomography (SD-OCT). METHODS: A total of 140 healthy women aged 18-29 years (mean age ± standard deviation SD, 24.5 ± 1.7 years) with different BMI, axial length (AL) ≤ 24 ± 1.0 mm, and spherical equivalent refraction (SER) of ≤ ±2.0 dioptres were enrolled for the study. The participants were age and refractionmatched, and grouped into underweight (BMI ≤ 18.0 kg/m2) (n = 30), normal (control group) (18.5-24.9 kg/m2) (n = 43), overweight (25.0-29.9 kg/m2) (n=37), and obese study groups (≥ 30.0 kg/m2) (n = 30). SD-OCT imaging was performed on one eye of each participant. Comparisons among groups for all locations and the associations between CT and other variables were examined. RESULTS: The mean CT at the subfoveal region (285 ± 31 µm, range: 203 µm to 399 µm) was significantly greater, and it was the lowest in the nasal region (248 ± 26 µm, range 154 to 304) compared with other locations, across all the groups (p < 0.05). Compared with the control, the subfoveal choroid was thinner in the obese group (mean difference: 22.6 µm, 95% Confidence Interval; CI: 8.6 µm to 36.6 µm; p = 0.02) and across all locations (p < 0.05) but thicker at the temporal location in the underweight group (12.4 µm, 95% CI: -23.7 µm to -1.04 µm; p = 0.01). No significant association of subfoveal CT with any of the measured parameters, including age (p-values ranged from 0.10 to 0.90), was found. CONCLUSION: BMI may have an influence on the CT of healthy individuals and could be a cofounder in research studies on CT. It is, therefore, recommended that BMI should be evaluated in the clinical diagnosis and management of conditions associated with choroid in healthy individuals.

Structural alterations of the choroid evaluated using enhanced depth imaging optical coherence tomography in patients with coronavirus disease.

PURPOSE: To assess choroidal changes using enhanced depth imaging optical coherence tomography in coronavirus disease (COVID-19). METHODS: Thirty-two patients with moderate COVID-19 and 34 healthy subjects were included in the study. Choroidal thickness was measured at 3 points as follows: at the subfovea, 1500 mm nasal to the fovea, and 1500 mm temporal to the fovea. The total choroidal area, luminal area, stromal area, and choroidal vascular index were measured with Image-J. All the measurements were performed during the disease and at 4 months after remission. RESULTS: In the patient group, the subfoveal, nasal, and temporal choroidal thicknesses were decreased as compared with those in the controls, but without statistically significant differences (p=0.534, p=0.437, and p=0.077, respectively). The mean total choroidal, stromal, and luminal areas and choroidal vascular index were statistically significantly decreased in the patient group (p<0.001, p=0.001, p=0.001, and p=0.003; respectively). At 4 months after remission, the choroidal structural parameters and choroidal vascular index revealed statistically significant increases as compared with the baseline measurements in the patients with COVID-19 (all p<0.001 and p=0.047, respectively). CONCLUSION: The choroidal vascular and stromal parameters showed significant transient decreases during the disease course of COVID-19.

Three-dimensional segmentation and depth-encoded visualization of choroidal vasculature using swept-source optical coherence tomography.

The choroid provides nutritional support for the retinal pigment epithelium and photoreceptors. Choroidal dysfunction plays a major role in several of the most important causes of vision loss including age-related macular degeneration, myopic degeneration, and pachychoroid diseases such as central serous chorioretinopathy and polypoidal choroidal vasculopathy. We describe an imaging technique using depth-resolved swept-source optical coherence tomography (SS-OCT) that provides full-thickness three-dimensional (3D) visualization of choroidal anatomy including topographical features of individual vessels. Enrolled subjects with different clinical manifestations within the pachychoroid disease spectrum underwent 15 mm × 9 mm volume scans centered on the fovea. A fully automated method segmented the choroidal vessels using their hyporeflective lumens. Binarized choroidal vessels were rendered in a 3D viewer as a vascular network within a choroidal slab. The network of choroidal vessels was color depth-encoded with a reference to the Bruch's membrane segmentation. Topographical features of the choroidal vasculature were characterized and compared with choroidal imaging obtained with indocyanine green angiography (ICGA) from the same subject. The en face SS-OCT projections of the larger choroid vessels closely resembled to that obtained with ICGA, with the automated SS-OCT approach proving additional depth-encoded 3D information. In 16 eyes with pachychoroid disease, the SS-OCT approach added clinically relevant structural details, including choroidal thickness and vessel depth, which the ICGA studies could not provide. Our technique appears to advance the in vivo visualization of the full-thickness choroid, successfully reveals the topographical features of choroidal vasculature, and shows potential for further quantitative analysis when compared with other choroidal imaging techniques. This improved visualization of choroidal vasculature and its 3D structure should provide an insight into choroid-related disease mechanisms as well as their responses to treatment.

NEW INSIGHTS INTO THE ASSOCIATION BETWEEN CHOROIDAL VESSELS AND CHORIOCAPILLARIS IN NORMAL EYES.

PURPOSE: To determine the relationship between large-sized and medium-sized choroidal vessels and choriocapillaris using the three-dimensional choroidal vascularity index (3D CVI) and percentage of flow deficits (FD%). METHODS: Prospective observational study. The main outcome measures included choroidal volume parameters (3D CVI, mean choroidal thickness, total choroidal volume, choroidal luminal volume, and choroidal stromal volume), choriocapillaris parameters (FD%, average area of FD, and FD count), and age and axial length. RESULTS: A total of 63 healthy individuals with an average age of 40.60 ± 12.32 years were included in this study. Univariate analysis showed that FD% (R = 0.295, P = 0.019) and area of FD (R = 0.276, P = 0.028) were significantly positively associated with 3D CVI, and FD count was negatively associated with 3D CVI (R = -0.297, P = 0.018). After adjusting for age and axial length, a significant correlation between FD% and 3D CVI (R = 0.264, P = 0.039) and between area of FD and 3D CVI remained (R = 0.267, P = 0.037). However, no significant correlation was found between FD count and 3D CVI after adjusting for axial length (R = -0.220, P = 0.085). CONCLUSION: In healthy individuals, choroidal vessel dilatation as suggested by elevated 3D CVI may lead to decreased choriocapillaris perfusion, which was correlated with an enlarged area of FD in choriocapillaris.

A new optical coherence tomography method for subfoveal choroidal thickness measurement: A single-center observational study.

ABSTRACT: Several macular pathologies are associated with choroidal vascular supply and thus require choroidal thickness evaluation. However, there is no standard subfoveal choroidal thickness (SFCT) measurement method. This study investigated a new method of SFCT measurement, using optical coherence tomography.This is a single-center observational study. Eighty-two senior medical students participated as observers and independently measured the SFCT on 5 standard optical coherence tomography images of healthy adults in a tertiary care setting. They used 3 different methods: the observer's own method, the conventional method, perpendicular to the retinal pigment epithelium, and the new method, along a virtual line connecting the umbo with the most elevated point of the ellipsoid. Additionally, the SFCT angle-the angle between the measurement line and the vertical line of the image-was measured and compared between methods. The intraclass correlation coefficient was used to determine interpersonal variability.The intraclass correlation coefficients for SFCT, measured using methods 1, 2, and 3, were 0.853, 0.880, and 0.896, respectively (P < .001 for all). Method 3 was the highest. The intraclass correlation coefficients of the SFCT angles were 0.647, 0.842, and 0.307, respectively (P < .001 for all).The new method showed the lowest interpersonal variability and could therefore be a reliable standard for SFCT measurement, even in foveae with a steep slope on optical coherence tomography.Trial registration: Not applicable.

The effects of pharmacological accommodation and cycloplegia on axial length and choroidal thickness / Efeitos da acomodação farmacológica e da cicloplegia no comprimento axial e na espessura da coroide

ABSTRACT Purpose: To investigate the effects of pharmacological accommodation and cycloplegia on ocular measurements. Methods: Thirty-three healthy subjects [mean (±SD) age, 32.97 (±5.21) years] volunteered to participate in the study. Measurement of the axial length, macular and choroidal thickness, refractive error, and corneal topography, as well as anterior segment imaging, were performed. After these procedures, pharmacological accommodation was induced by applying pilocarpine eye drops (pilocarpine hydrochloride 2%), and the measurements were repeated. The measurements were repeated again after full cycloplegia was induced using cyclopentolate eye drops (cyclopentolate hydrochloride 1%). The correlations between the measurements were evaluated. Results: A significant increase in subfoveal choroidal thickness after applying 2% pilocarpine was identified (without the drops, 319.36 ± 90.08 µm; with pilocarpine instillation, 341.60 ± 99.19 µm; with cyclopentolate instillation, 318.36 ± 103.0 µm; p<0.001). A significant increase in the axial length was also detected (without the drops, 23.26 ± 0.83 mm; with pilocarpine instillation, 23.29 ± 0.84 mm; with cyclopentolate instillation, 23.27 ± 0.84 mm; p=0.003). Comparing pharmacological accommodation and cycloplegia revealed a significant difference in central macular thickness (with pilocarpine instillation, 262.27 ± 19.34 µm; with cyclopentolate instillation, 265.93 ± 17.91 µm; p=0.016). Pilocarpine-related miosis (p<0.001) and myopic shift (p<0.001) were more severe in blue eyes vs. brown eyes. Conclusion: Pharmacological accommodation may change ocular measurements, such as choroidal thickness and axial length. This condition should be considered when performing ocular measurements, such as intraocular lens power calculations.(AU)

RESUMO Objetivo: Investigar os efeitos da acomodação farmacológica e da cicloplegia nas medições oculares. Métodos: participaram do estudo 33 voluntários saudáveis (média de idade [± DP], 32,97 anos [± 5,21 anos]). Foram medidos o comprimento axial, a espessura macular e coroidal e o erro refrativo, bem como realizados exames de imagem da topografia corneana e do segmento anterior. Em seguida, foi induzida a acomodação farmacológica aplicando-se colírio de pilocarpina (cloridrato de pilocarpina a 2%) e as medições foram repetidas nos participantes. As mesmas medições foram repetidas depois de induzir a cicloplegia completa com colírio de ciclopentolato (cloridrato de ciclopentolato a 1%) e foram avaliadas as correlações entre as medidas. Resultados: Identificou-se aumento significativo da espessura coroidal subfoveal com o uso da pilocarpina a 2% (sem colírio, 319,36 ± 90,08 µm; com a instilação de pilocarpina, 341,60 ± 99,19 µm; com a instilação de ciclopentolato, 318,36 ± 103,0 µm; p<0,001). Detectou-se também aumento significativo do comprimento axial (sem colírio, 23,26 ± 0,83 mm; com a instilação de pilocarpina, 23,29 ± 0,84 mm; com a instilação de ciclopentolato, 23,27 ± 0,84 mm; p=0,003). Ao se comparar a acomodação farmacológica e a cicloplegia, houve diferença significativa na espessura macular central (com a instilação de pilocarpina, 262,27 ± 19,34 µm; com a instilação de ciclopentolato, 265,93 ± 17,91 µm; p=0,016). Observou-se que a miose associada à pilocarpina (p<0,001) e o desvio miópico (p<0,001) foram mais severos nos olhos azuis que nos castanhos. Conclusão: A acomodação farmacológica pode alterar medidas oculares como a espessura da coroide e o comprimento axial. Essa possibilidade deve ser levada em consideração ao se efetuarem medições oculares, tais como cálculos de potência de lentes intraoculares.(AU)

Retinal and choroidal vascularity changes in healthcare professionals wearing FFP3 respirators.

PURPOSE: To evaluate short-term retinal and choroidal vascularity changes in the healthcare professionals after four hours of use filtering facepiece respirators (FFR). MATERIALS AND METHODS: This prospective study included 20 healthcare professionals. Oxygen saturation, pulse rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), mean ocular perfusion pressure (MOPP), and spectral domain optical coherence tomography (OCT) imaging were evaluated at baseline and after four hours wearing of FFP3 FFRs without an exhalation valve. Superior temporal artery (STA), inferior temporal artery (ITA), superior temporal vein (STV), and inferior temporal vein (ITV) diameter were measured from OCT images. The total subfoveal choroidal area (TCA), luminal area (LA), stromal area (SA) choroidal vascularity index [(CVI), the ratio of LA to TCA] were determined after binarization of enhanced depth imaging OCT (EDI-OCT) images of the choroid. RESULTS: The mean age of the participants was 27.35 ± 2.80 years (range, 25-34). Eight of them were female and 12 were male. After wearing the FFR for four hours, a significant decrease was observed in the mean DBP (p = 0.018), MAP (p = 0.016), and MOPP (p = 0.007) when compared to base-line values. STV diameter (p = 0.019) and ITV diameter (p = 0.046) measurements were found significantly higher than baseline measurements. A significant increase in the choroidal vascularity was observed in the LA (p = 0.004) and TCA values (p = 0.043) after wearing the FFR for four hours. CONCLUSION: The current study shows that after four hours usage of FFR, in addition to systemic changes, retinal and choroidal vascularity might be affected significantly. With further studies, long-term effects and clinical significance of these short-term changes should be investigated on healthcare professionals.

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.

Assessment of the choroidal structure in pregnant women in the first trimester.

We investigated the anatomical differences in the choroidal structure between pregnant women in the first trimester of pregnancy and age-matched healthy nonpregnant women using enhanced depth imaging optical coherence tomography (EDI-OCT) and choroidal binarization analysis. The main parameters measured in the two study groups, namely, pregnant women in the first trimester and healthy nonpregnant women, were choroidal thickness and the choroidal luminal area. Binarization of the EDI-OCT images from each patient was performed, and the choroidal vascularity index (CVI) was calculated. The correlations between the baseline characteristics of the subjects and the CVI were investigated using linear mixed model analysis. As a result, there was no statistically significant difference in the mean age, best-corrected visual acuity, axial length, central retinal thickness, subfoveal choroidal thickness, systolic blood pressure (BP), or diastolic BP between the two study groups. Conversely, a significant difference was observed in the CVI (P = 0.012) between the two groups. The multivariate analysis identified a significant correlation between the CVI and the systolic BP (P = 0.0044, linear mixed test). Taken together, a larger choroidal luminal area was associated with a higher systolic BP, especially in the first trimester of pregnancy. Our findings may provide further insight into the choroidal changes that occur during pregnancy.

The Evaluation of the Relation Between Iris and Choroidal Thickness.

Purpose: The study aimed to investigate the relationship between iris thickness (IT) and choroidal thickness (CT) in healthy subjects.Materials and Methods: Forty-five healthy participants (24 women, 21 men) aged 18-62 years were included in the study. The iris thickness was measured by anterior segment optical coherence tomography (AS-OCT). The iris thickness was measured at 750 µm (IT750T) and 2000 µm (IT2000T) from the temporal scleral spur. The iris thickness was measured at 750 µm (IT750N) and 2000 µm (IT2000N) from the nasal scleral spur. Choroidal thickness was measured by optical coherence tomography. Choroid thickness was measured at 750 µm (CT750N, CT750T) and 2000 µm (CT2000N, CT2000T) from the center of the fovea on both the nasal and temporal sides.Results: There were significant correlations between CT750T and IT750T, IT750N, IT2000N (r = 0.409, p=0.005; r = 0.396, p=0.007; r = 0.329, p=0.02, respectively). There were significant correlations between CT2000T and IT750T, IT750N, IT2000N (r = 0.383, p=0.009; r = 0.478, p=0.001; r = 0.331, p0=0.02, respectively).Conclusions: There was a significant correlation between CT and IT thicknesses at different points.