Optic Disc Diameter Research Articles

PM2.5 Exposure as a Risk Factor for Optic Nerve Health in Type 2 Diabetes Mellitus

(1) Objective: This study investigated the relationship between long-term particulate matter (PM2.5) exposure and optic disc parameters—vertical cup-to-disc ratio (vCDR), vertical optic disc diameter (vDD), and vertical optic cup diameter (vCD)—in patients with type 2 diabetes mellitus (T2DM). (2) Methods: A cross-sectional analysis was conducted using data from 65,750 T2DM patients in the 2017–2018 Shanghai Cohort Study of Diabetic Eye Disease (SCODE). Optic disc parameters were extracted from fundus images, and PM2.5 exposure was estimated using a random forest model incorporating satellite and meteorological data. Multivariate linear regression models were applied, adjusting for confounders including age, gender, body mass index, blood pressure, glucose, time of T2DM duration, smoking, drinking, and physical exercise. (3) Results: A 10 μg/m3 increase in PM2.5 exposure was associated with significant reductions in vCDR (−0.008), vDD (−42.547 μm), and vCD (−30.517 μm) (all p-values < 0.001). These associations persisted after sensitivity analyses and adjustments for other pollutants like O3 and NO2. (4) Conclusions: Long-term PM2.5 exposure is associated with detrimental changes in optic disc parameters in patients with T2DM, suggesting possible optic nerve atrophy. Considering the close relationship between the optic nerve and the central nervous system, these findings may also reflect broader neurodegenerative processes.

Generating Synthesized Fluorescein Angiography Images From Color Fundus Images by Generative Adversarial Networks for Macular Edema Assessment.

To assess the feasibility of generating synthetic fluorescein angiography (FA) images from color fundus (CF) images using pixel-to-pixel generative adversarial network (pix2pixGANs) for clinical applications. Research questions addressed image realism to retinal specialists and utility for assessing macular edema (ME) in Retinal Vein Occlusion (RVO) eyes. We used a registration-guided pix2pixGANs method trained on the CF-FA dataset from Kham Eye Centre, Kandze Prefecture People's Hospital. A visual Turing test confirmed the realism of synthetic images without novel artifacts. We then assessed the synthetic FA images for assessing ME. Finally, we quantitatively evaluated the synthetic images using Fréchet Inception distance (FID) and structural similarity measures (SSIM). The raw development dataset had 881 image pairs from 349 subjects. Our approach is capable of generating realistic FA images because small vessels are clearly visible and sharp within one optic disc diameter around the macula. Two retinal specialists agreed that more than 85% of synthetic FA images have good or excellent image quality. For ME detection, accuracy was similar for real and synthetic images. FID demonstrated a 38.9% improvement over the previous state-of-the-art (SOTA), and SSIM reached 0.78 compared to the previous SOTA's 0.67. We developed a pix2pixGANs model translating FA images from label-free CF images, yielding reliable synthetic FA images. This suggests potential for noninvasive evaluation of ME in RVO eyes using pix2pix GANs techniques. Pix2pixGANs techniques have the potential to assist in the noninvasive clinical assessment of ME in RVO eyes.

Longitudinal changes of funduscopic optic disc size, color and cup-to-disc ratio in school children

BackgroundTo investigate the relationship between changes in the optic disc size and color, cup-to-disc (C/D) ratio, and axial elongation in schoolchildren.MethodsA prospective cohort study was performed in 75 right eyes of elementary school students for six years (from 8.5 to 14.5 years old). In the first and last year, all participants underwent optical axial length measurement and color fundus photography. The optic disc color was calculated by dividing the intensity of red by the sum of the intensity of red, green, and blue. The optic disc area was calculated by modifying the number of pixels according to Bennett’s formula. The C/D ratio was calculated by dividing the vertical cup diameter by vertical optic disc diameter. Wilcoxon signed rank test was used to compare these optic disc parameters and axial length in the first and last year.ResultsMean axial length in the last year (24.82 mm) was significantly longer than that in the first year (23.34 mm). Likewise, the mean optic disc size was significantly smaller in the last year (41,946 pixels) than that in the first year (46,144 pixels). The mean optic disc color in the last year (0.49) was significantly more reddish than that in the first year (0.46), while the mean C/D ratio in last year (0.50) was significantly smaller than that in first year (0.52).ConclusionsDuring the period from 8.5 years to 14.5 years of age, both the optic disc size and C/D ratio became smaller, while the color became more red.

Time-Resolved Dynamic Optical Coherence Tomography for Retinal Blood Flow Analysis.

Optical coherence tomography (OCT) representations in clinical practice are static and do not allow for a dynamic visualization and quantification of blood flow. This study aims to present a method to analyze retinal blood flow dynamics using time-resolved structural OCT. We developed novel imaging protocols to acquire video-rate time-resolved OCT B-scans (1024 × 496 pixels, 10 degrees field of view) at four different sensor integration times (integration time of 44.8 µs at a nominal A-scan rate of 20 kHz, 22.4 µs at 40 kHz, 11.2 µs at 85 kHz, and 7.24 µs at 125 kHz). The vessel centers were manually annotated for each B-scan and surrounding subvolumes were extracted. We used a velocity model based on signal-to-noise ratio (SNR) drops due to fringe washout to calculate blood flow velocity profiles in vessels within five optic disc diameters of the optic disc rim. Time-resolved dynamic structural OCT revealed pulsatile SNR changes in the analyzed vessels and allowed the calculation of potential blood flow velocities at all integration times. Fringe washout was stronger in acquisitions with longer integration times; however, the ratio of the average SNR to the peak SNR inside the vessel was similar across all integration times. We demonstrated the feasibility of estimating blood flow profiles based on fringe washout analysis, showing pulsatile dynamics in vessels close to the optic nerve head using structural OCT. Time-resolved dynamic OCT has the potential to uncover valuable blood flow information in clinical settings.

Predicting optic atrophy in patients with anterior uveitis by computed tomography-based assessment of optic nerve diameter

Background: An objective assessment of factors for ocular inflammation and its sequelae and diagnostic assessment of possible development of the sequelae in early phases of uveitis are essential for early and effective treatment of endogenous uveitis. Purpose: To determine whether it is possible to predict optic atrophy in patients with anterior uveitis using computed tomography (CT)-based assessment of optic nerve diameter. Material and Methods: Patients with anterior uveitis underwent a routine eye examination (ophthalmoscopy, biomicroscopy, intraocular pressure (IOP) measurement, and Humphrey perimetry). In addition, they underwent CT-based assessment of optic disc diameter at 3-5 mm from the entrance into the orbit in the affected eye and the contralateral healthy eye. Patients received treatment as per the protocol. Results: The percentage difference in optic nerve diameter between patients with uveitis complicated by optic neuritis and those with uveitis only for affected eyes was large (33.1%) and statistically significant. At 3 months and 6 months after initiation of treatment, mean optic disc diameter in patients with optic neuritis decreased by 37.2% and 49.1%, respectively, compared to baseline values. At 6 months, a decrease in optic nerve diameter among optic neuritis patients was observed both in those who received treatment and in those who failed to receive treatment, but was less marked in the former patients. Particularly, from 3 months to 6 months, optic nerve diameter decreased by 17.3% in treated optic neuritis patients versus 23.5% in those who remained untreated. Conclusion: CT-based data on the change in the optic nerve diameter at the entrance into the orbit in patients with optic neuritis is an objective characteristic of the presence and grade of atrophic process. Early identification of the potential for development of optic atrophy in individuals with optic neuritis will make it possible to treat them early and, consequently, to prevent or stabilize the process.

Fundus Tessellated Density Assessed by Deep Learning in Primary School Children.

To explore associations of fundus tessellated density (FTD) and compare characteristics of different fundus tessellation (FT) distribution patterns, based on artificial intelligence technology using deep learning. Comprehensive ocular examinations were conducted in 577 children aged 7 years old from a population-based cross-sectional study, including biometric measurement, refraction, optical coherence tomography angiography, and 45° nonmydriatic fundus photography. FTD was defined as the average exposed choroid area per unit area of the fundus, and obtained by artificial intelligence technology. The distribution of FT was classified into the macular pattern and the peripapillary pattern according to FTD. The mean FTD was 0.024 ± 0.026 in whole fundus. Multivariate regression analysis showed that greater FTD was significantly correlated with thinner subfoveal choroidal thickness, larger parapapillary atrophy, greater vessel density inside the optic disc, larger vertical diameter of optic disc, thinner retinal nerve fiber layer, and longer distance from optic disc center to macular fovea (all P < 0.05). The peripapillary distributed group had larger parapapillary atrophy (0.052 ± 0.119 vs 0.031 ± 0.072), greater FTD (0.029 ± 0.028 vs 0.015 ± 0.018), thinner subfoveal choroidal thickness (297.66 ± 60.61 vs 315.33 ± 66.46), and thinner retinal thickness (285.55 ± 10.89 vs 288.03 ± 10.31) than the macular distributed group (all P < 0.05). FTD can be applied as a quantitative biomarker to estimate subfoveal choroidal thickness in children. The role of blood flow inside optic disc in FT progression needs further investigation. The distribution of FT and the peripapillary pattern correlated more with myopia-related fundus changes than the macular pattern. Artificial intelligence can evaluate FT quantitatively in children, and has potential value for assisting in myopia prevention and control.

Fundus autofluorescence abnormalities can predict fluorescein angiography abnormalities in patients with chronic central serous chorioretinopathy.

This study is to assess the possible correlation between findings on fundus autofluorescence (FAF) and fluorescein angiography (FA) in patients with chronic central serous chorioretinopathy (cCSC). This multicentre retrospective cohort study included 71 cCSC patients (92 eyes) with at least 6months of follow-up, who had a FAF-FA imaging discrepancy larger than 0.5 optic disc diameters in size in the corresponding areas of hyperfluorescent abnormalities. A comparison was performed between progression in size of areas of hyperautofluorescent retinal pigment epithelium (RPE) abnormalities on FAF (HF-FAF) and the hyperfluorescent areas on FA (HF-FA) at first visit and last visit. The possible correlations were estimated between FAF-FA discrepancy and disease characteristics. The median area of HF-FAF at first visit was 7.48mm2 (1.41-27.9). The median area of HF-FA at first visit and last visit was 2.40mm2 (0.02-17.27) and 5.22mm2 (0.53-25.62), respectively. FAF-FA discrepancy was associated with follow-up duration and the area of HF-FAF at first visit. A mathematical algorithm for grading FAF-FA discrepancy in time was suggested, which predicted the enlargement of hyperfluorescent RPE abnormalities on FA in 82.6% of cases. There is a statistically significant relationship between the areas of HF-FAF and HF-FA in cCSC patients with FAF-FA imaging discrepancy at first presentation. Long-term changes in RPE alterations in cCSC on FA can be predicted based on baseline HF-FAF and follow-up duration.

Optic disc and retinal vascular features in first 6 years of Chinese children.

Retinal microvasculature plays an important role in children's fundus lesions and even in their later life. However, little was known on the features of normal retina in early life. The purpose of this study was to explore the normal retinal features in the first 6 years of life and provide information for future research. Children, aged from birth to 6 years old and diagnosed with various unilateral ocular diseases were included. Venous phase fundus fluorescein angiography images with the optic disc at the center were collected. Based on the ResUNet convolutional neural network, optic disc and retinal vascular features in the posterior retina were computed automatically. A total of 146 normal eyes of 146 children were included. Among different age groups, no changes were shown in the optic disc diameter (y = -0.00002x + 1.362, R2 = 0.025, p = 0.058). Retinal vessel density and fractal dimension are linearly and strongly correlated (r = 0.979, p < 0.001). Older children had smaller value of fractal dimension (y = -0.000026x + 1.549, R2 = 0.075, p = 0.001) and narrower vascular caliber if they were less than 3 years old (y = -0.008x + 84.861, R2 = 0.205, p < 0.001). No differences were in the density (y = -0.000007x + 0.134, R2 = 0.023, p = 0.067) and the curvature of retinal vessels (lnC = -0.00001x - 4.657, R2 = 0.001, p = 0.667). Age and gender did not impact the optic disc diameter, vessel density, and vessel curvature significantly in this group of children. Trends of decreased vessel caliber in the first 3 years of life and decreased vessel complexity with age were observed. The structural characteristics provide information for future research to better understand the developmental origin of the healthy and diseased retina.

A physical sign of pathological myopia: myopic scleral pit

PurposeMyopic scleral pit (MSP) is a rare physical sign of pathological myopia (PM). The aim of this study was to summarize the clinical characteristics of MSP and analyze its correlation with PM.MethodsEight cases with PM and MSP were enrolled in this study. Comprehensive ophthalmic examinations, including subjective refraction, slit-lamp biomicroscope, intraocular pressure, fundus photographs, A- and B-scan ultrasonography and spectral-domain optical coherence tomography, were performed.ResultsAll the patients had a long history of PM with visual impairment, long axial length, and myopia-related fundus degeneration. Mean axial length was 31.48 ± 2.17 mm. Mean size of MSP was 0.69 ± 0.29 optic disc diameter (PD). Mean logMAR BCVA was 1.21 ± 0.88 logMAR. Spearman correlation analysis showed that the logMAR BCVA had no correlation with the size of pits (P = 0.34). Fundus examination revealed a focal pale concave located in the sclera exposed area of retinal choroid atrophy was found in all cases. OCT showed a deep scleral pit where the retinal choroid was thin or absent, without retinal sensory detachment or sensory defect.ConclusionsThis study identified a rare scleral lesion in all eight individuals with PM, which was termed “myopic scleral pit”. This phenomenon is different from focal choroidal excavation and posterior staphyloma.

The impact of the image conversion factor and image centration on retinal vessel geometric characteristics.

This study aims to use fundus image material from a long-term retinopathy follow-up study to identify problems created by changing imaging modalities or imaging settings (e.g., image centering, resolution, viewing angle, illumination wavelength). Investigating the relationship of image conversion factor and imaging centering on retinal vessel geometric characteristics (RVGC), offers solutions for longitudinal retinal vessel analysis for data obtained in clinical routine. Retinal vessel geometric characteristics were analyzed in scanned fundus photographs with Singapore-I-Vessel-Assessment using a constant image conversion factor (ICF) and an individual ICF, applying them to macula centered (MC) and optic disk centered (ODC) images. The ICF is used to convert pixel measurements into μm for vessel diameter measurements and to establish the size of the measuring zone. Calculating a constant ICF, the width of all analyzed optic disks is included, and it is used for all images of a cohort. An individual ICF, in turn, uses the optic disk diameter of the eye analyzed. To investigate agreement, Bland-Altman mean difference was calculated between ODC images analyzed with individual and constant ICF and between MC and ODC images. With constant ICF (n = 104 eyes of 52 patients) the mean central retinal equivalent was 160.9 ± 17.08 μm for arteries (CRAE) and 208.7 ± 14.7.4 μm for veins (CRVE). The individual ICFs resulted in a mean CRAE of 163.3 ± 15.6 μm and a mean CRVE of 219.0 ± 22.3 μm. On Bland-Altman analysis, the individual ICF RVGC are more positive, resulting in a positive mean difference for most investigated parameters. Arteriovenous ratio (p = 0.86), simple tortuosity (p = 0.08), and fractal dimension (p = 0.80) agreed well between MC and ODC images, while the vessel diameters were significantly smaller in MC images (p < 0.002). Scanned images can be analyzed using vessel assessment software. Investigations of individual ICF versus constant ICF point out the asset of utilizing an individual ICF. Image settings (ODC vs. MC) were shown to have good agreement.

Dynamic Changes in Retinal Vessel Diameters and Arteriovenous Ratio within 10 Days of Birth

Purpose This study monitored the dynamic changes in retinal vascular width and the AVR in full-term neonates within 1–10 days of birth. Methods It was conducted at hospitals in the Anhui province from October 2020 to March 2022. A total of 700 full-term, healthy infants were chosen randomly within 10 days of birth, and the Star Pupil Medical Cloud Data System (XBDS) was used to collect fundus images. Infants within 6 days of birth were grouped into groups one to six, while those within the 7th to 10th days were grouped into group seven. The fundus photographs were imported into Image-Pro-Plus (IPP) software. The optic disc diameter was measured. The retinal artery and vein’s diameter was measured at a distance between 0.5- and 1.0-disc diameter from the optic disc’s margin. The AVR was also calculated. Finally, each group’s retinal vessel diameters and AVR were compared separately to show their dynamic changes. Results There were differences in the retinal artery diameter between groups one and two, three and four, four and five, and five and six. For retinal vein diameter, there were differences between groups one and two and groups six and seven. There were also differences in the AVR between all groups. In addition, there was a significant positive correlation between the small retinal artery and vein diameters. Conclusion The retinal artery and vein diameters and AVR in neonates change dynamically during the first 10 days of life. The AVR undergoes the most dramatic change daily and is considerably smaller than the AVR in adults. Hence, this study found that the external environment undergoes significant changes following birth that affect the microcirculation. Then, the retinal central vascular system undergoes similar emergency and adaptive alterations.

Optical and biometric indicators of the eye in children with juvenile glaucoma combined with myopia

Purpose. To analyze optical and biometric indicators of children's eyes with various stages of congenital juvenile glaucoma (CJG) combined with myopia.Material and methods. We examined 17 patients (31 eyes) aged 11 to 17 (averagely 14.0 ± 0.2 years) diagnosed with CYG who underwent, prior to surgical or conservative treatment, a regular ophthalmological examination supplemented with the measurement of the central corneal thickness (on an automatic contactless tonometer-pachymeter by NIDEK, USA), and the index of corneal deformation (ICD) by the Shkrebets technique.Results. The analysis showed a possible correlation between 1) tonometric intraocular pressure (Pt) and the axial length of the eye, 2) Pt and the ratio of excavation to optic disk diameter (E/ON), 3) axial length of the eye and the central corneal thickness at the terminal CYG stage, and 4) the axial length and the refraction at the initial stage of CYG.Conclusion. As the glaucomatous process progresses, children with CYG combined with myopia show an increase of myopic refraction, a decrease in fibrous membrane rigidity, pretrabecular and trabecular changes, axial elongation, increased IOP due to an imbalance between the production of intraocular fluid and its outflow, an expansion of the excavation of the optic disk and a decrease in the central corneal thickness.

Regression-Based Strategies to Reduce Refractive Error-Associated Glaucoma Diagnostic Bias When Using OCT and OCT Angiography.

PurposeThe purpose of this study was to correct refractive error-associated bias in optical coherence tomography (OCT) and OCT angiography (OCTA) glaucoma diagnostic parameters.MethodsOCT and OCTA imaging were obtained from participants in the Hong Kong FAMILY cohort. The Avanti/AngioVue OCT/OCTA system was used to measure the peripapillary nerve fiber layer thickness (NFLT), peripapillary nerve fiber layer plexus capillary density (NFLP-CD), macular ganglion cell complex thickness (GCCT), and macular superficial vascular complex vascular density (SVC-VD). Healthy eyes, including ones with axial ametropia, were enrolled for analysis.ResultsA total of 1346 eyes from 792 participants were divided into 4 subgroups: high myopia (<−6D), low myopia (−6D to −1D), emmetropia (−1D to 1D), and hyperopia (>1D). After accounting for age, sex, and signal strength, multivariable regression showed strong dependence in most models for NFLT, GCCT, and NFLP-CD on axial eye length (AL), spherical equivalent (SE) refraction, and apparent optic disc diameter (DD). Optical analysis indicated that AL-related transverse optical magnification variations predominated over anatomic variations and were responsible for these trends. Compared to the emmetropic group, the false positive rates were significantly (Chi-square test P < 0.003) elevated in both myopia groups for NFLT, NFLP-CD, and GCCT. Regression-based adjustment of these diagnostic parameters with AL or SE significantly (McNemar test P < 0.03) reduced the elevated false positive rates.ConclusionsMyopic eyes are biased to have lower NFLT, GCCT, and NFLP-CD measurements. AL- and SE-based adjustments were effective in mitigating this bias.Translational RelevanceAdoption of these adjustments into commercial OCT systems may reduce false positive rates related to refractive error.

Inter-eye Comparison of the Lamina Cribrosa Depth in Patients with Bilateral Normal-tension Glaucoma with Asymmetrical Damage

Purpose: To evaluate the association between lamina cribrosa depth (LCD) and the severity of glaucomatous damage in patients with normal-tension glaucoma (NTG).Methods: The optic nerve heads (ONHs) of patients with bilateral NTG showing asymmetrical damage were scanned using spectral-domain optical coherence tomography. LCDs were measured on ONH horizontal B-scan images at three locations equidistant across the vertical optic disc diameter and compared between the more damaged and contralateral eyes. Conditional logistic regression analysis was performed to identify ocular risk factors associated with more severe damage between the eyes.Results: One hundred and four eyes of 52 patients with bilateral NTG were included. The mean age was 66.0 ± 15.0 years; there were 31 males and 21 females. The more damaged eyes exhibited a higher baseline intraocular pressure (IOP) (p &lt; 0.001), a thinner global retinal nerve fiber layer thickness (p &lt; 0.001), and worse visual field mean deviation (p &lt; 0.001) and a pattern standard deviation (p &lt; 0.001), than the contralateral eyes. In contrast, we found no significant inter-eye difference in either the spherical equivalent or the axial length. The average LCD was significantly larger in the more damaged eyes (529.4 ± 116.7 vs. 482.9 ± 107.5 μm, p &lt; 0.001). On conditional logistic regression analysis, the higher the baseline IOP (p = 0.006) and the larger the LCD (p = 0.003), the higher the risk of having more severe damage compared to the contralateral eye under similar systemic conditions.Conclusions: The LCD was significantly larger in the more damaged eyes of patients with bilateral NTG, suggesting that LC deformation might be associated with glaucomatous ONH damage in NTG eyes.

Intravenous lipo-prostaglandin E1 administration for patients with acute central retinal artery occlusion

ObjectiveThis study aimed to investigate the anatomical and functional changes in patients with central retinal artery occlusion (CRAO) (n=21) treated with 10 µg/day intravenous liposomal prostaglandin E1 (lipo-PGE1).Methods and analysisWe...

Morphologic Changes in the Lamina Cribrosa Upon Intraocular Pressure Lowering in Patients With Normal Tension Glaucoma.

PurposeThe purpose of this study was to investigate whether the lamina cribrosa (LC) curve changes in response to intraocular pressure (IOP) reduction following administration of topical ocular hypotensive eye drops in eyes with normal tension glaucoma (NTG).MethodsNinety-three eyes of 93 patients with treatment naïve NTG at initial examination and with ≥20% reduction from baseline IOP following administration of topical ocular hypotensive eye drops were included. Serial horizontal B-scan images of the optic nerve head (ONH) were obtained from each eye using enhanced depth imaging spectral domain optical coherence tomography (OCT) before and 1 year after IOP-lowering treatment. The LC curvature in each eye was assessed by measuring the LC curvature index (LCCI) in horizontal OCT B-scan images obtained at three (superior, central, and inferior) locations spaced equidistantly across the vertical optic disc diameter before and after IOP-lowering treatment. We evaluated the OCT detectible change in the LC curvature based on the interval change of LCCI to exceed the intersession standard deviation of 1.96 times and factors associated with the magnitude of the LCCI change in the eyes showing significant LC change.ResultsIOP decreased from 15.7 ± 2.5 mm Hg at baseline to 11.2 ± 1.7 mm Hg after topical glaucoma medication. Among the 93 subjects, 62 (66.7%) eyes showed the significant reduction of the LCCI (interssetional change over 1.5) after the treatment; greater interssessional change of the LCCI after IOP reduction was associated with younger age (P = 0.020) and larger baseline LCCI (P < 0.001).ConclusionsThe OCT detectible changes in LC curvature occurred in response to a modest decrease in the IOP in the naïve NTG eyes. The therapeutic benefit of these changes need to be assessed in longitudinal studies.

Assessment of peripapillary choroidal thicknesses and optic disc diameters in idiopathic intracranial hypertension

ObjectifÉvaluer les variations de l’épaisseur choroïdienne péripapillaire (ECP) et du diamètre du disque optique dans les yeux de patients qui présentaient une hypertension intracrânienne idiopathique (HII) lorsque le disque optique était œdématié et une fois l’œdème papillaire résolu. NatureIl s'agit d'une étude transversale d'observation. On a réalisé une tomographie par cohérence optique (OCT) dans les 2 yeux de patients présentant une HII, que l'on avait divisés en 2 groupes: 18 patients en proie à un œdème papillaire aigu et 25 patients chez lesquels l’œdème papillaire était résolu. Vingt autres participants en bonne santé ont également pris part à l’étude. MéthodesDans le cadre de cette étude transversale d'observation, on a mesuré par OCT l’épaisseur de la couche de fibres nerveuses rétiniennes, de la choroïde péripapillaire et du complexe de cellules ganglionnaires, de même que le diamètre du disque optique. RésultatsDans le groupe de patients chez lesquels l’œdème papillaire avait disparu, l'ECP était significativement moindre dans tous les quadrants, comparativement à ce qui a été mesuré dans le groupe témoin (p < 0,001 pour chacune des mesures). Dans le groupe de patients qui présentaient un œdème papillaire aigu, l'ECP dans les quadrants temporal, inférieur et supérieur était significativement moindre que dans les yeux témoins (p < 0,001, p = 0,003 et p = 0,049, respectivement). Les diamètres vertical et horizontal du disque optique étaient également significativement plus importants en présence d’œdème papillaire, comparativement à ce qui a été mesuré dans les yeux témoins et dans les yeux qui ne présentaient plus d’œdème papillaire (p < 0,001 pour chacune des mesures). ConclusionL'ECP diminue tant dans la phase aiguë que chronique de l'HII, tandis que le diamètre du disque optique augmente en présence d'HII et d’œdème papillaire.

Optic disc morphology in preterm children. Influence of gestational age and birth weight

The characteristics of the optic disc and the development of the optic nerve can affect visual function in children. The purpose of our study was to assess optic disc morphology in preterm infants and to determine whether it is influenced by gestational age, birth weight and the presence of a retinopathy of prematurity. In a retrospective study, RetCam fundus images of 109 premature newborns admitted to our tertiary-level neonatal intensive care unit were reviewed. We evaluated the cup to disc ratio (C/D), optic disc diameter, cup diameter, shape of the optic disc, adherence to the ISNT rule, and presence of a peripapillary atrophy. Of 218 photos, we found the following results: mean±SD gestational age 28.5±2.7 weeks, mean±SD birth weight 1122±394g, mean C/D 0.32. There was no significant correlation between C/D and gestational age or birth weight. Vertical disc diameter was greater than horizontal disc diameter, with a mean ratio (horizontal/vertical) of 4/5, lending an oval shape to the optic disc. Nineteen infants had retinopathy of prematurity in both eyes; ninety-three percent had peripapillary atrophy. In our study, optic disc morphology in premature newborns was not influenced by gestational age, birth weight or presence of premature retinopathy.

Metabolic Long-Term Monitoring of Transcorneal Electrical Stimulation in Retinitis Pigmentosa

Introduction: Transcorneal electrical stimulation (TES) is a new therapeutical approach for retinitis pigmentosa (RP). With progression of RP, degeneration of photoreceptors results in lower oxygen consumption of the retina. Retinal oximetry (RO) is a noninvasive method to analyze oxygen saturation in retinal vessels and has shown promising short-term results as a therapy monitoring tool for TES. The aim of our study was to measure the long-term effects of TES on RO parameters over a period of 3 years (3Y). Methods: A total of 18 eyes of 9 subjects (5♀ 4♂) suffering from RP were examined at baseline (BL), 6 months, and 3Y of TES (OkuStim®) treatment. TES was performed for 30 min once a week at 200% of the individual phosphene threshold simultaneously on both eyes. The oxygen saturation was examined at BL and following TES therapy with the oxygen saturation tool of the Retinal Vessel Analyser (IMEDOS Systems UG, Jena, Germany). The global oxygen saturation parameters (in %), within 1.0–1.5 optic-disc diameters from the disc margin, in retinal arterioles (A-SO₂) and venules (V SO₂) were measured and their difference (A-V SO₂) was calculated. In addition, we recorded the diameters in the main arterioles (D-A) and venules (D-V). ANOVA-based linear mixed-effects models were employed for statistical analysis using SPSS®. Results: After 3Y of TES treatment both the mean A-SO₂ (from 96.35 ± 12.76% to 100.89 ± 5.87%, p = 0.22) and V SO₂ (from 62.20 ± 11.55% to 64.55 ± 8.24%, p = 0.77) increased slightly. The A-V SO₂, which corresponds to the oxygen consumption of the retina, presented also with a slight increment from 34.15 ± 9.68% at BL to 36.23 ± 7.71% without reaching statistical significance (p = 0.27). TES also did not appear to alter the vascular diameter parameters, D-A and D-V (p > 0.05). Conclusion: Our long-term observations indicate that TES therapy in RP might lead to a slight increment in oxygen consumption of the retina. However, a larger cohort and longer duration may be needed to adequately power a follow-up study and to confirm this trend reflecting a possible benefit of TES for RP.

Retinal Ganglion Counts in invasive Iguana iguana

Introduction Iguana iguana is an emerging invasive species in southeastern North America. To better understand their ability to outcompete native species for local resources, we investigate retina ganglion cell density in order to begin characterization visual acuity potential. Materials and Methods: We obtained four specimens from wildlife veterinarians culling invasive iguanas from southern Florida. Postmortem, we conducted whole globe enucleation, with special consideration to record globe orientation within the orbit. We performed retinal wholemounts and stained retinae for retinal ganglion cells with cresyl violet acetate. We photographed the retina at 100X and counted retinal ganglion cells in randomly generated areas using Image J. Cell counts were verified by three independent and blinded investigators. We generated a cell retina showing retinal ganglion cell density across the retina, indicating the position of the fovea. Results By combining the orientation of the retina within the globe and orbit and the map of retinal ganglion cell density, our results show a single macula and fovea that is located nasally approximately one optic disc diameter anterior to the optic disc, indicating that Iguana iguana has the highest visual acuity in the temporal visual field. Conclusion Retinal ganglion cell counts in Iguana iguana indicate a highly visual animal with good visual acuity. This may help us understand their success as an invasive species.