José Ignacio 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.

Assessment of lower tear meniscus measurements obtained with Keratograph and agreement with Fourier-domain optical-coherence tomography

Aims To compare intraobserver repeatability and interobserver and intersession reproducibility of lower tear meniscus height measurements (LTMH) obtained with the new Keratograph 5M and a Fourier-domain optical-coherence tomography (OCT; Spectralis OCT) and to assess the agreement between the two devices. Methods This is a observational cross-sectional study. Thirty eyes of 30 normal subjects were randomly imaged twice with both devices in our setting. Two examiners randomly made LTMH measurements using the devices. To assess intraobserver repeatability and interobserver and intersession reproducibility within-subject SD (Sw), test–retest repeatability, coefficient of variation (CoV) and intraclass correlation coefficients (ICCs) were calculated. Agreement between both devices was also determined. Results Average LMTH for Keratograph was 235.46±57.61 μm, whereas the mean LTMH measured by OCT was 245.84±67.18 μm. Intraobserver repeatability and interobserver and intersession reproducibility were moderate with Keratograph (CoV ≥0.16%, ≥0.19%, ≥0.17% and ICC ≤0.83, ≤0.76, ≤0.83, respectively) and high for the Spectralis OCT (CoV ≤0.13%, ≤0.12%, ≤0.11% and ICC ≥0.9, ≥0.92, ≥0.92, respectively). No statistically significant difference was detected in mean LMTH measurements made with both devices, although correlation was low (CoV 0.25%, ICC 0.55). Conclusions Spectralis OCT LTMH measurements were more reliable than the new Keratograph data. Agreement between the devices was poor.

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.

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.].

Lower Tear Meniscus Measurements Using a New Anterior Segment Swept-Source Optical Coherence Tomography and Agreement With Fourier-Domain Optical Coherence Tomography

PURPOSE To assess intraobserver repeatability and interobserver and intersession reproducibility of lower tear meniscus height (LTMH) measurements obtained using a new anterior segment swept-source optical coherence tomography (SS-OCT) device. Agreement with Fourier-domain (FD) OCT (Spectralis) was also examined. METHODS In an observational cross-sectional study, one eye of 29 healthy subjects was randomly imaged with both devices at our center. Two examiners then randomly measured the LTMH using the softwares calipers. To assess intraobserver repeatability and interobserver and intersession reproducibility, within-subject standard deviation (Sw), test-retest repeatability, coefficients of variation (CoV), and intraclass correlation coefficients (ICCs) were calculated. Agreement between both devices was also determined in Bland-Altman plots. RESULTS Mean LTMHs for SS-OCT and FD-OCT were 276.6 ± 87.6 and 280.3 ± 80 μm, respectively. Using the SS-OCT device, intraobserver CoV, interobserver CoV, and intersession CoV were found to be ≥16.9%, ≤7.2%, and ≤11.5%, respectively. ICCs for these parameters were ≤88%, ≥97%, and ≥94%, respectively. Bland-Altman analysis indicated poor agreement between SS-OCT and FD-OCT, and the correlation was low (CoV 34.5%, ICC 0.36). CONCLUSIONS SS-OCT LTMH measurements showed excellent interobserver and intersession repeatability along with good intraobserver reproducibility. Agreement between the devices was poor.PURPOSE To assess intraobserver repeatability and interobserver and intersession reproducibility of lower tear meniscus height (LTMH) measurements obtained using a new anterior segment swept-source optical coherence tomography (SS-OCT) device. Agreement with Fourier-domain (FD) OCT (Spectralis) was also examined. METHODS In an observational cross-sectional study, one eye of 29 healthy subjects was randomly imaged with both devices at our center. Two examiners then randomly measured the LTMH using the softwares calipers. To assess intraobserver repeatability and interobserver and intersession reproducibility, within-subject standard deviation (Sw), test-retest repeatability, coefficients of variation (CoV), and intraclass correlation coefficients (ICCs) were calculated. Agreement between both devices was also determined in Bland-Altman plots. RESULTS Mean LTMHs for SS-OCT and FD-OCT were 276.6 ± 87.6 and 280.3 ± 80 μm, respectively. Using the SS-OCT device, intraobserver CoV, interobserver CoV, and intersession CoV were found to be ≥16.9%, ≤7.2%, and ≤11.5%, respectively. ICCs for these parameters were ≤88%, ≥97%, and ≥94%, respectively. Bland-Altman analysis indicated poor agreement between SS-OCT and FD-OCT, and the correlation was low (CoV 34.5%, ICC 0.36). CONCLUSIONS SS-OCT LTMH measurements showed excellent interobserver and intersession repeatability along with good intraobserver reproducibility. Agreement between the devices was poor.

Uvemaster: A Mobile App-Based Decision Support System for the Differential Diagnosis of Uveitis.

Purpose To examine the diagnostic accuracy and performance of Uvemaster, a mobile application (app) or diagnostic decision support system (DDSS) for uveitis. The app contains a large database of knowledge including 88 uveitis syndromes each with 76 clinical items, both ocular and systemic (total 6688) and their respective prevalences, and displays a differential diagnoses list (DDL) ordered by sensitivity, specificity, or positive predictive value (PPV). Methods In this retrospective case-series study, diagnostic accuracy (percentage of cases for which a correct diagnosis was obtained) and performance (percentage of cases for which a specific diagnosis was obtained) were determined in reported series of patients originally diagnosed by a uveitis specialist with specific uveitis (N = 88) and idiopathic uveitis (N = 71), respectively. Results Diagnostic accuracy was 96.6% (95% confidence interval [CI], 93.2-100). By sensitivity, the original diagnosis appeared among the top three in the DDL in 90.9% (95% CI, 84.1-96.6) and was the first in 73.9% (95% CI, 63.6-83.0). By PPV, the original diagnosis was among the top DDL three in 62.5% (95% CI, 51.1-71.6) and the first in 29.5% (95% CI, 20.5-38.6; P < 0.001). In 71 (31.1%) patients originally diagnosed with idiopathic uveitis, 19 new diagnoses were made reducing this series to 52 (22.8%) and improving by 8.3% the new rate of diagnosed specific uveitis cases (performance = 77.2%; 95% CI, 71.1-82.9). Conclusions Uvemaster proved accurate and based on the same clinical data was able to detect more cases of specific uveitis than the original clinician only-based method.

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.

Variations in retinal nerve fiber layer measurements on optical coherence tomography after implantation of trifocal intraocular lens

Purpose: To establish the changes produced after implantation of a trifocal intraocular lens (IOL) on retinal nerve fiber layer measurements performed with Fourier-domain optical coherence tomography (OCT). Methods: This prospective study included 100 eyes of 50 patients with bilateral cataract in surgical range, no other associated ocular involvement, refractive errors between +5 and −5 spherical diopters, and less than 1.5 D of corneal astigmatism. The eyes were operated by phacoemulsification with implantation of 2 different trifocal IOLs (FineVision and AT LISA tri 839MP) in randomized equal groups. Cirrus OCT and Spectralis OCT were performed before surgery and 3 months later. Both analyzed the thickness of the nerve fiber layer and thickness divided by quadrants (6 in case of Spectralis and 4 in case of Cirrus HD). Results: The mean age of patients was 67.5 ± 5.8 years. The global nerve fiber layer thickness measured with Spectralis OCT was 96.77 μm before surgery and 99.55 μm after. With Cirrus OCT, the global thickness was 85.29 μm before surgery and 89.77 μm after. Statistically significant differences in global thickness measurements between preimplantation and postimplantation of the IOL were found with both OCT in the 2 groups. Statistically significant differences were also found in temporal and superior quadrants. Conclusions: The implantation of a diffractive trifocal IOL alters the results of the optic nerve fiber layer on Fourier-domain OCT in these patients, which should be taken into account in the posterior study of these patients.