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121 result(s) for "López-Miguel, Alberto"
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Relationship between the main components of the crystalline lens and the anterior chamber depth after cataract formation
PurposeTo assess the relationship between anterior chamber depth (ACD) and lens thickness (LT), as well as its three main components (anterior and posterior cortex and nucleus thickness), in cataractous and non-cataractous eyes, depending on the axial length (AxL).MethodsAnterior and posterior cortex and nucleus thickness of the crystalline lens, ACD, and AxL were measured using optical low-coherence reflectometry in cataractous and non-cataractous eyes. They were also classified into hyperopia, emmetropia, myopia, and high myopia, depending on AxL; thus, eight subgroups were created. A minimum sample size of 44 eyes (of 44 patients) for each group was recruited. Linear models were fitted for the whole sample and each AxL subgroup to assess if there were differences in the relationships between the crystalline lens variables and ACD, including age as a covariate.ResultsThree hundred seventy cataract patients (237 females, 133 males) and 250 non-cataract controls (180 females, 70 males), aged 70.5 ± 9.4 and 41.9 ± 15.5 years, respectively, were recruited. The mean AxL, ACD, and LT for the cataractous and non-cataractous eyes were 23.90 ± 2.05, 24.11 ± 2.11, 2.64 ± 0.45, and 2.91 ± 0.49, 4.51 ± 0.38, 3.93 ± 0.44 mm, respectively. The inverse relationship of LT, anterior and posterior cortex, and nucleus thickness with ACD was not significantly (p ≥ 0.26) different between cataractous and non-cataractous eyes. Further subclassification of the sample depending on AxL showed that the inverse relationship between the posterior cortex and ACD was no longer significant (p > 0.05) for any non-cataractous AxL group. LT, anterior and posterior cortex, and nucleus thickness was not significantly (p ≥ 0.43) different between cataractous and non-cataractous eyes for the whole sample, and all AxL groups after adjusting for age.ConclusionsThe presence of cataracts does not modify the inverse relationship of the LT, anterior and posterior cortex, and nucleus with ACD. And this relationship does not seem to depend importantly on AxL. Besides, the possible differences in LT, anterior and posterior cortex, and nucleus between cataractous and non-cataractous eyes may not be caused by lens opacification, but possibly by the progressive lens growth due to aging.
Effect of a single vectored thermal pulsation treatment of Meibomian gland dysfunction patients under controlled environmental conditions
To assess the prophylactic effect of LipiFlow treatment in Meibomian gland dysfunction (MGD) patients exposed to an adverse environmental humidity. MGD patients were exposed to normal (23 °C; 50% relative humidity; 30 min) and adverse (23 °C; 10% relative humidity; 2 h) controlled environments consecutively during baseline and follow-up visits (3, 6, and 12 months) after a single LipiFlow treatment. Ocular Surface Disease Index (OSDI), lipid layer thickness (LLT), fluorescein tear break-up time (TBUT), corneal and conjunctival staining, change in dry eye symptoms questionnaire (CDES-Q), and Meibomian gland yielding liquid secretion (MGYLS), were assessed. Linear mixed-effects and cumulative logit mixed models were fitted to assess the effect of the LipiFlow treatment over time and within the controlled environments. Seventeen females and 4 males (59.6 ± 9.4 years) completed the study. LLT and TBUT did not vary significantly ( p  > 0.05) after LipiFlow treatment. OSDI, corneal and conjunctival staining, and MGYLS scores were improved ( p  ≤ 0.01) 12 months after treatment. After the adverse exposure, corneal staining increased at all visits ( p  = 0.01), and there was no significant improvement in CDES-Q scores after LipiFlow treatment ( p  ≥ 0.07). One LipiFlow treatment improved objective and subjective outcomes in MGD disease for at least one year. Further studies are needed to support that LipiFlow might also help as an adjuvant to avoid acute flares against an adverse environmental humidity.
Senile Cataract Formation Does Not Affect Crystalline Lens Thickness
Introduction Characterizing lens thickness (LT) in patients with cataracts is important for better understanding the lens aging process and for designing new intraocular lens power formulas. This study aimed to analyze the influence of common senile cataract formation on the LT, anterior (ACS) and posterior (PCS) cortex space, and nuclear thickness (NT), controlling for sex, age, and axial length. Methods A cross-sectional study was performed. A consecutive sample of 603 volunteers (403 women, 200 men) aged 59.1 ± 18.8 years was recruited. The standardized Lens Opacification Classification System (LOCS)-III was used to classify eyes (randomly selected) into cataractous and non-cataractous groups. Also, they were classified according to the cataract location (presence or absence of cortical, nuclear, or posterior subcapsular cataract). Optical biometry was performed to measure LT, ACS, NT, and PCS. Propensity score was used to match participants one-to-one for sex, age, and axial length. Groups were compared using the Student’s t  test or Yuen’s test. Results The four classifications divided unmatched eyes into: 361 cataractous lenses and 242 non-cataractous, 226 cortical and 377 non-cortical cataractous, 313 nuclear and 290 non-nuclear cataractous and 242 subcapsular and 361 non-subcapsular cataractous. Before matching, cataractous eyes showed significantly higher LT (4.52 ± 0.39 vs. 3.94 ± 0.46 mm, p  < 0.001), ACS (0.75 ± 0.20 vs. 0.58 ± 0.23 mm, p  < 0.001), NT (3.34 ± 0.23 vs. 3.18 ± 0.25 mm, p  < 0.001) and PCS (0.42 ± 0.19 vs. 0.37 ± 0.19 mm, p  = 0.003). Matched lens, cortical, nuclear, and subcapsular cataract samples comprised 146, 258, 182, and 226 eyes, respectively. After matching, no significant differences were observed in LT (4.34 ± 0.37 vs. 4.33 ± 0.36 mm, p  = 0.94), ACS (0.72 ± 0.20 vs. 0.76 ± 0.19 mm, p  = 0.08), NT (3.31 ± 0.22 vs. 3.30 ± 0.23 mm, p  = 0.24) and PCS (0.42 ± 0.19 vs. 0.43 ± 0.16 mm, p  = 0.79). Conclusions The presence of senile cortical, nuclear, and posterior subcapsular cataract have no effect on LT, ACS, NT, and PCS. Confounding factors should be controlled for when measuring LT and its main components.
New Method for the Automated Assessment of Corneal Nerve Tortuosity Using Confocal Microscopy Imaging
An automated tool for corneal nerve fiber tortuosity quantification from in vivo confocal microscopy (IVCM) is described and evaluated. The method is a multi-stage process based on the splitting of the corneal nerve fibers into individual segments, whose endpoints are an extreme or intersection of white pixels on a binarized image. Individual segment tortuosity is quantified in terms of the arc-chord ratio. Forty-three IVCM images from 43 laser-assisted in situ keratomileusis (LASIK) surgery patients were used for evaluation. Images from symptomatic dry eye disease (DED) post-LASIK patients, with (n=16) and without (n=7) ocular pain, and non-DED post-LASIK controls (n=20) were assessed. The automated tortuosity measure was compared to a manual grading one, obtaining a moderate correlation (Spearman’s rank correlation coefficient = 0.49, p=0.0008). The new tortuosity index was significantly higher in post-LASIK patients with ocular pain than in control patients (p=0.001), while no significant differences were detected with manual measurement (p>0.28). The tortuosity quantification was positively correlated with the ocular surface disease index (OSDI) and a numeric rating scale (NRS) assessing pain (p=0.0012 and p=0.0051, respectively). The results show good performance of the proposed automated methodology for the evaluation of corneal nerve tortuosity.
Short-Term Efficacy of Ophthalmic Cyclosporine: A 0.1% Cationic Emulsion in Dry Eye Patients Assessed Under Controlled Environment
Introduction To evaluate the short-term efficacy of cyclosporine A (CsA)-0.1% cationic emulsion (CE) in patients with dry eye disease (DED) and mitigation of the inflammatory flares triggered by desiccating stress environments. Methods A single-center non-randomized clinical trial was performed at a tertiary care setting. Twenty patients with DED treated with CsA 0.1% CE were exposed to a normal controlled environment (NCE) (23 °C, 50% relative humidity) and an adverse controlled environment (ACE) (23 °C, 10% relative humidity, 0.43 m/s localized airflow) during baseline and the 1- and 3-month visits. Patients underwent the following evaluations: conjunctival hyperemia and staining, corneal fluorescein staining (CFS) using the Oxford and Cornea and Contact Lens Research Unit (CCLRU) scale, meibomian gland (MG) secretion quality, Dry Eye Questionnaire-5, Symptom Assessment in Dry Eye (SANDE II), and Change in Dry Eye Symptoms Questionnaire. Multivariate models were adjusted for statistical analysis. Results Nineteen women and one man (mean age, 58.9 ± 12.3 years) completed the study. All symptom questionnaires, CFS, conjunctival hyperemia and staining, and MG secretion quality improved ( p  ≤ 0.003) with 1 month of treatment; improvements were maintained after 3 months ( p  ≤ 0.02), except for SANDE II ( p  ≥ 0.07). The CFS worsening (total CCLRU) after baseline ACE exposure (from 8.6 to 10.1) was higher, although not significant ( p  = 0.64), compared with 1 month (from 5.4 to 5.8) and 3 months (from 5.0 to 5.9) after treatment. Conclusion Topical CsA-0.1% CE improved DED signs and symptoms after 1 month of treatment under controlled environmental conditions. Future studies should confirm the benefit of CsA-0.1% CE in desiccating stress environments. Trial Registration ClinicalTrials.gov identifier, NCT04492878.
Monochromatic higher order aberrations in highly myopic eyes with Staphyloma
Background Prevalence of high myopia is continuously increasing, thus, patients affected with staphyloma are abundant worldwide. Assessment of the quality of vision in these patients is mandatory for a proper clinical counselling, specially when undergoing surgical procedures that require intraocular lenses implantation. Thus, the purpose of the study was to assess monochromatic higher order aberrations (HOAs) in highly myopic eyes with staphyloma with or without a dome-shaped macula. Methods Participants underwent spectral-domain optical coherence tomography, ocular axial biometry, dual Scheimpflug photography and integrated Placido disk topography, and Hartmann-Shack wavefront analysis. Five groups were evaluated: a low-moderate myopia control group (< 6.00 diopters, n  = 31) and four high myopia (≥6.00 diopters) groups: eyes without staphyloma ( n  = 18), eyes with inferior staphyloma ( n  = 14), eyes with posterior staphyloma without dome-shaped macula ( n  = 15) and eyes with posterior staphyloma with dome-shaped macula ( n  = 17). Subsequently, two new groups (including all participants) were created to assess differences between myopia with and without staphyloma. One-way analysis of covariance was performed using age and lens densitometry as covariates. Results Statistically significant ( p  ≤ 0.05) differences in anterior corneal fourth-order HOAs were observed between the low-moderate myopia and no-dome-shaped macula (Mean: 0.16 μm) and dome-shaped macula posterior staphyloma groups (Mean: 0.12 μm) in younger patients (≤45 years old). The same groups also showed ( p  ≤ 0.05) significant differences for anterior corneal primary spherical aberration (Mean: 0.19 and 0.13 μm, respectively). In addition, anterior corneal tetrafoil was significantly higher ( p  = 0.04) in dome-shaped macula compared to no-dome-shaped macula (Mean: 0.18 vs 0.06 μm, respectively). When all participants were grouped together, significantly lower mean anterior corneal primary spherical aberration (0.15 μm vs. 0.27 μm, p  = 0.004) and higher internal primary spherical aberration (0.04 μm vs. -0.06 μm, p  = 0.04) was observed in staphyloma compared to no-staphyloma myopic patients. Conclusions Eyes with high myopia and staphyloma have less positive anterior corneal primary spherical aberration and less negative internal primary spherical aberration, suggesting that the anterior corneal surface tends to mimic in a specular fashion the posterior pole profile. This corneal behaviour appears to change in patients older than 45 years.
Influence of decentration and tilt of Tecnis ZCB00 on visual acuity and higher order aberrations
Background/ObjectivesTo determine the influence of decentration and tilt of a pseudophakic aspheric intraocular lens (IOL) on visual acuity (VA) and higher-order aberrations (HOAs), and to analyze the agreement between pupil center/axis and iridocorneal angles center/axis when assessing IOL decentration and tilt.Subjects/MethodsA prospective interventional case series study including thirty-three patients undergoing Tecnis ZCB00 (Abbott Medical Optics) implantation. IOL decentration and tilt with respect to two reference systems (pupil and iridocorneal angles centers/axes), in cartesian (X,Y) and polar (radius/tilt, polar angle/azimuth) coordinates, were assessed with optical coherence tomography. VA and internal and ocular HOAs were evaluated. Multiple linear regression models and intraclass correlation coefficient (ICC) were computed.ResultsIOL decentration only showed a significant effect on internal HOAs for Z33 (R2 = 0.20, P = 0.04). IOL decentration with respect to the pupil center showed a significant effect on ocular Z3−3 (R2 = 0.18, P = 0.05), Z31 (R2 = 0.36, P = 0.001) and Z4−4 (R2 = 0.24, P = 0.02); and with respect to the center of iridocorneal angles, on ocular Z33 (R2 = 0.21, P = 0.03), Z42 (R2 = 0.32, P = 0.003), primary coma (R2 = 0.41, P < 0.001), and coma-like (R2 = 0.40, P = 0.001). Poor agreement between both reference systems was found for IOL decentration measurements (ICC ≤ 0.41), except for the polar angle coordinate (ICC = 0.83). Tilt measurements showed good agreement (ICC ≥ 0.75).ConclusionsTecnis ZCB00 decentration and tilt values after uneventful implantation appear not to have influence on VA, and their effect on HOAs are not high enough to clinically affect quality of vision. Pupil and iridocorneal angles used as reference systems may be interchangeable for IOL tilt measurements, but not for decentration.
Comparison of specular microscopy and ultrasound pachymetry before and after cataract surgery
Purpose To compare specular microscopy (Topcon SP-3000P, Topcon Corporation, Tokyo, Japan) and ultrasound (US) technology when evaluating central corneal thickness (CCT) prior to and after phacoemulsification. Methods Corneal edema was assessed in phacoemulsification patients due to senile cataract by measuring CCT preoperatively and 1 day, 1 month, and 3 months postoperatively. Bland–Altman analysis was performed to assess interchangeability between pachymetry techniques for each visit. Repeated measures analysis of variance was performed to evaluate variation in CCT agreement depending on the degree of corneal edema. Results One hundred and eighteen patients aged 73.9 ± 10.1 years were recruited. Topcon SP-3000P provided significant ( p  < 0.0001) lower CCT values than US with and without induced corneal edema. Mean differences between CCT techniques for baseline, 1 day, 1 month and 3 months after cataract surgery were −28.9 ± 22.6, −30.5 ± 41.4, −32.3 ± 16.2 and −33.0 ± 16.9 μm, respectively. The systematic bias observed was not significantly different among the 4 visits (p = 0.59). The estimated limits of agreement (based on 1.96 standard deviation) were substantial, being 90.5, 165.8, 64.9 and 67.5 um at baseline, 1 day and 1 and 3 months. Conclusions Topcon SP-3000P provides similar systematic bias in comparison with US technique for CCT measurements regardless of the degree of corneal edema after phacoemulsification, which should be reduced after applying a constant calibration adjustment of ∼30 μm. However, interchangeability between techniques may be still limited by the notable random measurement error.
Can we measure mesopic pupil size with the cobalt blue light slit-lamp biomicroscopy method?
Background The aim of this work is to assess a previously described slit-lamp biomicroscopy-based method (SLBM) for measuring pupil diameter and compare it to Colvard infrared pupillometry (CIP). Methods Two examiners performed three repeated measurements with each instrument in 40 healthy eyes. We determined the agreement of SLBM and CIP, intraobserver and interobserver repeatabilities, and interobserver concordance (kappa) and SLBM ability for detecting pupil sizes over 6.0 mm. Results The mean (±standard deviation [SD]) pupil diameter was 5.81 ± 0.70 mm with SLBM and 6.26 ± 0.68 mm with CIP ( p  = 0.01) averaging both examiner’s results. Mean differences between the SLBM and CIP were –0.60 mm and –0.30 mm for each examiner using the average of the three readings ( p  = 0.02), and they were very similar using the first reading. Intraobserver reproducibility: the width of the 95% LoA ranged from 1.79 to 2.30 mm. The ICCs were 0.97 and 0.92 for SLBM, and 0.96 and 0.90 for CIP. Interobserver reproducibility: the width of the LoA ranged from 1.82 to 2.09 mm. Kappa statistics were 0.39 and 0.49 for the first and mean SLBM readings, respectively, and 0.45 for both the first and mean CIP readings. Sensitivity and specificity of SLBM for detection of pupils larger than 6 mm ranged from 55.56% to 73.68% and from 76.19% to 95.45%, respectively. The best trade-off between sensitivity and specificity ranged from 5.4 mm to 6.2 mm. Conclusions Although the SLBM is quite repeatable, it underestimates mesopic pupil size and shows a too wide range of agreement with CIP. SLBM shows low sensitivity in detecting pupils larger than 6 mm, which may be misleading when planning anterior segment surgery. Previous grading-consensus training strategies may increase interrater reproducibility, and compensation for the systematic underestimation could improve accuracy of the SLBM.