José Ángel Fernández-Vigo

Morphometry of the Trabecular Meshwork In Vivo in a Healthy Population Using Fourier-Domain Optical Coherence Tomography

PURPOSE We measured the length, thickness, and area of the trabecular meshwork (TM) in vivo using Fourier domain optical coherence tomography (FD-OCT) in a Caucasian population of healthy subjects. METHODS A cross-sectional study was done of 1006 healthy subjects. Left eyes were randomly selected. Age, sex, IOP, and spherical refractive error were noted. The depth and volume of the anterior chamber and the central corneal thickness were measured with Pentacam, while IOL Master was used to measure the axial length. The length, thickness, and area of the TM were measured through FD-OCT RTVue. A study was done to determine the correlation between TM size, and other demographic and ocular parameters. Finally, the reproducibility of the measurements was assessed for a subgroup of 50 eyes from 50 patients. RESULTS We were able to measure the TM in 91.1% of the total eyes studied. The mean TM length was 496.99 ± 92.77 μm (range, 275-800), TM thickness was 174.16 ± 28.14 μm (range, 100-276), and TM area was 0.069 ± 0.031 mm(2) (range, 0.023-0.133). No differences were found in terms of length and area for sex, although the TM was slightly thicker in men (P = 0.046). No correlation was observed between the TM measurements and any of the studied demographic or ocular parameters (R < 0.09, P < 0.001). Intra- and interobserver reproducibility of the measurements were good (intraclass correlation coefficient > 0.750, P < 0.001). CONCLUSIONS The FD-OCT is an effective and reproducible examination technique to measure the length, thickness, and area of the TM in vivo.

Fourier domain optical coherence tomography to assess the iridocorneal angle and correlation study in a large Caucasian population

BackgroundRecently, novel anatomic parameters that can be measured by optical coherence tomography (OCT), have been identified as a more objective and accurate method of defining the iridocorneal angle. The aim of the present study is to measure the iridocorneal angle by Fourier domain (FD) OCT and to identify correlations between angle measurements and subject factors in a large healthy Caucasian population.MethodsA cross sectional study was performed in 989 left eyes of 989 healthy subjects. The iridocorneal angle measurements: trabecular-iris angle (TIA), angle opening distance (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur, were made using the FD-OCT RTVue®. Iris thickness was also measured. Correlations were examined between angle measurements and demographic and ocular factors. The main determinants of angle width were identified by multivariate linear regression.ResultsTIA could be measured in 94 % of the eyes, and AOD500 and TISA500 in 92 %. The means recorded were TIA 35.8 ± 12.2 degrees (range 1.5 to 76.1), AOD500 542.6 ± 285.4 μm (range 15 to 1755), and TISA500 0.195 ± 0.104 mm2 (range 0.02 to 0.62). The correlation between the temporal and nasal quadrant was R = 0.902 for TIA. The reproducibility of measurements was excellent (intraclass correlation coefficient >0.947). Mean angle width measurements were smaller in women (p = 0.02). Correlation was detected between angle means and anterior chamber volume (ACV; R = 0.848), anterior chamber depth (ACD; R = 0.818), spherical error (R = -0.619) and age (R = -0.487), while no correlation was observed with Intraocular pressure (R = -0.052). ACV emerged as the main determinant of TIA (R2 = 0.705; p < 0.001).ConclusionsIn this Caucasian population, strong correlation was detected between FD-OCT anterior angle measurements and ACV, ACD, spherical refractive error and sex, emerging the ACV as the main determinant of TIA.

Determinants of anterior chamber depth in a large Caucasian population and agreement between intra‐ocular lens Master and Pentacam measurements of this variable

To establish the main determinants of anterior chamber depth (ACD) in Caucasian subjects and examine agreement between IOL Master® (Carl Zeiss, Meditec) and Pentacam® (Oculus Inc.) ACD measurements.

Prevalencia de retinopatía diabética en la ciudad de Badajoz 2002 (Proyecto Extremadura para prevención de la ceguera)

Objective: To establish the prevalence of diabetic retinopathy (DR), types and risk factors in a diabetic population in the city of Badajoz. Methods: A cross-sectional study, with prospective data collection, was performed in 2002 on 762 randomly selected diabetic patients belonging to two Primary Care Centers. We evaluated age, gender, type, treatment, duration of diabetes and blood pressure levels. Two color fundus photographs were taken and ophthalmoscopy performed on both eyes. Data were analyzed using SPSS (11.5). Results: The mean age of the patients was 66.2 (DS 11.4) years, 4.7% were type 1 diabetics, 29% were insulin-treated and 52.8% had elevated blood pressure. Prevalence of DR was 29.8%, macular edema 1.4% and proliferative DR 4.8%. Multivariate analysis showed that patients with an evolution of between 5 and 10 years had a frequency 1.13 times higher (ORaj 1.13; IC 95% 0.68-1.88; p=0.648) than those of less than 5 years evolution, while those with more than 15 years evolution had a fre

Agreement Between Three Optical Coherence Tomography Devices to Assess the Insertion Distance and Thickness of Horizontal Rectus Muscles

PURPOSE To assess the agreement between two different spectral domain (SD-OCT) and one swept source (SS-OCT) optical coherence tomography device to measure the insertion distance and the thickness of the horizontal rectus muscles. METHODS Seventy eyes from 35 healthy patients were studied. Three OCT instruments-Spectralis (Heidelberg Engineering Inc., Heidelberg, Germany), Cirrus 5000 (Carl Zeiss Meditec, Dublin, CA), and Triton (Topcon, Inc., Tokyo, Japan)-were used to measure the limbus insertion distance and the thickness of the lateral rectus and medial rectus muscles. The intraclass correlation coefficient (ICC) was calculated to determine the reproducibility and the agreement between the three methods. RESULTS Measurement of the limbus insertion distance was possible in 100% of cases with the three OCT devices. The thickness could be measured in 75% or more patients with Spectralis, 74% or more with Cirrus, and 78% or more with Triton. The agreement of the insertion distance measurements between the three devices ranged from an ICC of 0.629 or greater to 0.887; for the muscle thickness, the ICC ranged from 0.495 or greater to 0.854. The best agreement existed between the Spectralis and Topcon devices for insertion distance (ICC = 0.715 to 0.887) and for muscle thickness (ICC = 0.641 to 0.854). The reproducibility of each device was good and was higher for insertion distance (ICC = 0.880) than for muscle thickness (ICC = 0.736). The highest reproducibility values were obtained with Triton. CONCLUSIONS The three OCT devices permitted accurate and reproducible measurements of the limbus insertion distance and the thickness of the horizontal rectus muscles, showing moderate to good agreement between the SS-OCT and the two SD-OCT instruments. [J Pediatr Ophthalmol Strabismus. 2017;54(3):168-176.].

Anterior Chamber Angle and Trabecular Meshwork Measurements Made by Fourier-domain Optical Coherence Tomography in Healthy White Children

Purpose: To obtain anterior chamber angle and trabecular meshwork (TM) measurements by Fourier-domain optical coherence tomography (FD-OCT) in a population of healthy white children. Materials and Methods: This was a cross-sectional study examining 409 right eyes of 409 children. Trabecular-iris angle (TIA) and TM length and area were measured by FD-OCT (RTVue 100) in the nasal and temporal quadrants to analyze correlations between angle or TM measurements and age, sex, and refractive error. Results: Mean participant age was 10.5±3.4 years (range, 3 to 18 y); 51% were boys. Mean spherical error was 0.56±2.4 D (range, −9 to +7.5 D). TIA could be measured in 99%, whereas TM measurements could only be made in 83%. Mean TIA was 43.1±10.0 degrees (range, 16 to 76 degrees). No differences were observed in angle width according to sex (P=0.299; t test). TIA was correlated with age (R=0.204; P<0.001) and with spherical error (R=−0.457; P<0.001). Mean TM length was 530±106 &mgr;m (range, 299 to 891 &mgr;m) and mean TM area was 0.065±0.021 mm2 (range, 0.030 to 0.180 mm2). No correlation was observed between TM metrics and age, sex or refractive error (R<0.08; P≥0.172). Conclusions: FD-OCT proved useful for the noninvasive measurement of TIA and TM metrics in children. Spherical error was the main determinant of TIA.

Computational Study of Aqueous Humor Dynamics Assessing the Vault and the Pupil Diameter in Two Posterior-Chamber Phakic Lenses.

PURPOSE To compare the behavior of aqueous humor (AH) and analyze flow differences by comparing the volume and velocity of the flow after two different models of implantable collamer lens (ICL) placement. METHODS Computational fluid dynamics with numerical simulation using Ansys Fluent software was performed to compare the AH flow through a peripheral iridotomy (PI), which is typically performed after implantation of a V4b lens to the central hole of a V4c lens. The volume and flow rate in 24 scenarios were compared according to the type of lens, pupil diameter (PD) (3.5 or 5.5 mm), the vault (100, 350, and 800 μm) and the PI (single or double, 180 or 360 μm). RESULTS With a standard vault (350 μm) and a PD of 3.5 mm, the volume of AH that flows from the posterior to the anterior chamber through the PI (V4b lens: 73.4% in 360 μm and 17.3% in 180 μm) and for the central hole (V4c lens: 75.7%) is larger than in the case of a PD of 5.5 mm (13.9%, 0.91%, and 15.3% respectively). When the vault is low (100; PD 3.5 mm), the volume of AH that reaches the central hole of the V4c lens is diminished (52.0%), being 5.1% if the pupil is enlarged. CONCLUSIONS AH flow varies depending on the type of ICL implanted, whether it is implanted with an iridotomy or a central hole on the lens, the PD, and the vault.

Quantification of trabecular-iris contact and its prevalence by optical coherence tomography in a healthy Caucasian population

Purpose To determine the prevalence of trabecular-iris contact (TIC) and quantify this contact in healthy Caucasian individuals using Fourier-domain optical coherence tomography (FD-OCT). Methods For this cross-sectional study, 2,012 eyes of 1,006 healthy subjects were recruited among individuals undergoing a routine ophthalmologic checkup. In each participant, age, sex, intraocular pressure, and spherical refractive error were first recorded along with anterior chamber depth and volume, central corneal thickness measured with the Pentacam, and axial length with the IOLMaster. Anterior chamber angle variables and the presence of TIC in the horizontal quadrants were determined by anterior segment FD-OCT (RTVue 100®). When TIC was observed, TIC length (TICL) and its percentage in relation to the length of the trabecular meshwork (TICL percentage) were also measured. Results Trabecular-iris contact in the horizontal quadrants was observed in 34 eyes of 25 patients, representing 1.6% of the total number of eyes examined. In this subgroup of individuals, mean age was 55.8 years, 84% were women, and spherical refractive error ranged from -0.25 to 8.25 D. Eyes with TIC showed an angle width of less than 23.2 degrees and axial length shorter than 23.7 mm. Mean TICL was 239 ± 79 μm (103-495 μm) and mean TICL percentage was 46.9% ± 13.9% (17.2%-76.3%). Conclusions The prevalence of TIC was low in this population. Fourier-domain optical coherence tomography emerged as useful to assess its prevalence and quantify the extent of TIC.

Identificación de estructuras del ángulo iridocorneal mediante tomografía de coherencia óptica de dominio Fourier

OBJECTIVE To study the structures of the iridocorneal angle using anterior segment optical coherence tomography (OCT) defining their tomographic characteristics and quantifying their identification frequency. MATERIAL AND METHODS A cross-sectional study was performed on 267 right eyes of 267 consecutive healthy patients. Fourier domain OCT RTVue (Optovue Inc, CA, EE. UU.) was used to examine the iridocorneal angle in the nasal and temporal sectors. The structures evaluated were: Sclerocorneal limbus, sclerocorneal transition, Schwalbes line, trabecular meshwork, Schlemms canal, scleral spur, and angular recess. Within and between agreements to identify structures were calculated using Cohens kappa coefficient. RESULTS The mean age was 41.3 ± 14.3 years (range 20-80), with 57% being women. The sclerocorneal limbus, sclerocorneal transition, and Schwalbes line were identified by 98.7, 97 and 93.4% of the images, respectively, with the trabecular meshwork and Schlemms canal being identified in 91% of cases. The scleral spur could be identified in 85.4%, and the angular recess in 74.5%. There was no difference in the identification between the temporal and nasal sectors. Within and between agreement was k=0.92 and k=0.88, respectively, in the identification of the structures of the total images studied. CONCLUSIONS Fourier domain OCT is a reliable technique for the identification of the structures of the iridocorneal angle, among which can be highlighted are, the trabecular meshwork, Schlemms canal, scleral spur, and Schwalbes line.

Computational simulation of aqueous humour dynamics in the presence of a posterior-chamber versus iris-fixed phakic intraocular lens

Purpose To compare aqueous humour (AH) dynamics in the presence of a precrystalline (Implantable Collamer Lens®; ICL) or iris-fixed (Artiflex®) phakic intraocular lens (PIOL). Methods By computational fluid dynamics simulation, AH flow was modelled through a peripheral iridotomy (PI) or central lens hole (both 360 μm) in the presence of an Artiflex or ICL lens, respectively. The impacts of AH flow were then determined in terms of wall shear stress (WSS) produced on the endothelium or crystalline lens. Effects were also modelled for different scenarios of pupil diameter (PD 3.5 or 5.5 mm), ICL vault (100, 350, 800 μm) and number of Artiflex iridotomies (1 or 2) and location (12 or 6 o’clock). Results For a PD of 3.5 mm, AH volumes flowing from the posterior to the anterior chamber were 37.6% of total flow through the lens hole (ICL) and 84.2% through PI (Artiflex). For an enlarged PD (5.5 mm), corresponding values were 10.3% and 81.9% respectively, so PI constitutes a very efficient way of evacuating AH. Central endothelial WSS in Pa was lower for the large vault ICL and the Artiflex (1−03 and 1.1−03 respectively) compared to the PIOL-free eye (1.6−03). Crystalline lens WSS was highest for the lowest vault ICL (1−04). Conclusions AH flow varied according to the presence of a precrystalline or iris-fixed intraocular lens. Endothelial WSS was lower for an implanted ICL with large vault and Artiflex than in the PIOL-free eye, while highest crystalline WSS was recorded for the lowest vault ICL.