Morphogeometric analysis for characterization of keratoconus considering the spatial localization and projection of apex and minimum corneal thickness point

This work evaluates changes in new morphogeometric indices developed considering the position of anterior and posterior corneal apex and minimum corneal thickness (MCT) point in keratoconus. This prospective comparative study included 440 eyes of 440 patients (age, 7–99 years): control (124 eyes) and keratoconus (KC) groups (316 eyes). Tomographic information (Sirius®, Costruzione Strumenti Oftalmici, Italy) was treated with SolidWorks v2013, creating the following morphogeometric parameters: geometric axis–apex line angle (GA–AP), geometric axis–MCT line angle (GA–MCT, apex line–MCT line angle (AP–MCT), and distances between apex and MCT points on the anterior (anterior AP–MCTd) and posterior corneal surface (posterior AP–MCTd). Statistically significant higher values of GA–AP, GA–MCT, AP–MCT and anterior AP–MCTd were found in the keratoconus group (p ≤ 0.001). Moderate significant correlations of corneal aberrations (r ≥ 0.587, p < 0.001) and corneal thickness parameters (r ≤ −0.414, p < 0.001) with GA–AP and AP–MCT were found. Anterior asphericity was found to be significantly correlated with anterior and posterior AP–MCTd (r ≥ 0.430, p < 0.001). Likewise, GA–AP and AP–MCT showed a good diagnostic ability for the detection of keratoconus, with optimal cutoff values of 9.61° (sensitivity 85.5%, specificity 80.3%) and 18.08° (sensitivity 80.5%, specificity 78.7%), respectively. These new morphogeometric indices allow a clinical characterization of the 3-D structural alteration occurring in keratoconus, with less coincidence in the spatial projection of the apex and MCT points of both corneal surfaces. Future studies should confirm the potential impact on the precision of these indices of the variability of posterior corneal surface measurements obtained with Scheimpflug imaging technology.This publication has been carried out in the framework of the Thematic Network for Co-Operative Research in Health (RETICS), reference number RD16/0008/0012, financed by the Carlos III Health Institute–General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2013–2016) and the European Regional Development Fund (FEDER). The author David P. Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471

Scaffolds of Hyaluronic Acid Poly(Ethyl Acrylate) Interpenetrating Networks: Characterization and In Vitro Studies

Hyaluronic acid (HA) provides many advantages to regenerative implants through its bioactive properties, but it also has many limitations as a biomaterial if it is not chemically modified. In order to overcome some of these limitations, HA has been combined with poly(ethyl acrylate) in the form of interpenetrating polymeric networks (IPNs), in which the HA network is crosslinked with divinyl sulfone. Scaffolds of this IPN have been produced through a template-leaching methodology, and their properties have been compared with those of single-network scaffolds made of either PEA or crosslinked HA. A fibroblast cell line has been used to assess the in vitro performance of the scaffolds, revealing good cell response and a differentiated behavior on the IPN surface when compared to the individual polymers. Altogether, the results confirm that this type of material offers an interesting microenvironment for cells, which can be further improved toward its potential use in medical implants.Support of this work through projects PRI-PIMNEU-2011-1372 (ERANET-Neuron) and CICyT MAT2011-28791-C03-02 is gratefully acknowledged. The authors would like to thank PhD. Carmen Antolinos and PhD. Keila Alvarado for their assistance in the TMA assay. Assistance and advice received from the Electron Microscopy Service at the Universitat Politecnica de Valencia is also acknowledged.Rodríguez Pérez, E.; Lloret-Compañ, A.; Monleón Pradas, M.; Martínez-Ramos, C. (2016). Scaffolds of Hyaluronic Acid Poly(Ethyl Acrylate) Interpenetrating Networks: Characterization and In Vitro Studies. Macromolecular Bioscience. 16(8):1147-1157. https://doi.org/10.1002/mabi.201600028S1147115716

Prediction of the in vivo mechanical behavior of biointegrable acrylic macroporous scaffolds

[EN] This study examines a biocompatible scaffold series of random copolymer networks P(EA-HEA) made of Ethyl Acrylate, EA, and 2-Hydroxyl Ethyl Acrylate, HEA. The P(EA-HEA) scaffolds have been synthesized with varying crosslinking density and filled with a Poly(Vinyl Alcohol), PVA, to mimic the growing cartilaginous tissue during tissue repair. In cartilage regeneration the scaffold needs to have sufficient mechanical properties to sustain the compression in the joint and, at the same time, transmit mechanical signals to the cells for chondrogenic differentiation. Mechanical tests show that the elastic modulus increases with increasing crosslinking density of P(EA-HEA) scaffolds. The water plays an important role in the mechanical behavior of the scaffold, but highly depends on the crosslinking density of the proper polymer. Furthermore, when the scaffold with hydrogel is tested it can be seen that the modulus increases with increasing hydrogel density. Even so, the mechanical properties are inferior than those of the scaffolds with water filling the pores. The hydrogel inside the pores of the scaffolds facilitates the expulsion of water during compression and lowers the mechanical modulus of the scaffold. The P(EA-HEA) with PVA shows to be a good artificial cartilage model with mechanical properties close to native articular cartilage.This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2013-46467-C4-1-R (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. The authors acknowledge the assistance and advice of Electron Microscopy Service of the UPV.Vikingsson, L.; Antolinos Turpín, CM.; Gómez-Tejedor, JA.; Gallego Ferrer, G.; Gómez Ribelles, JL. (2016). Prediction of the in vivo mechanical behavior of biointegrable acrylic macroporous scaffolds. Materials Science and Engineering: C. 61:651-658. https://doi.org/10.1016/j.msec.2015.12.068S6516586

COVID-19 Disease and Ophthalmology: An Update

Ophthalmol Ther (2020) 9:415–426https://doi.org/10.1007/s40123-020-00260-y María A. Amnesty,&nbsp;Jorge L. Alió &nbsp;del Barrio,&nbsp;Jorge L. Alio M. A. Amnesty&nbsp;Oculoplastic Department, Vissum (Grupo Miranda), Alicante, Spain J. L. Alió del Barrio&nbsp;J. L. Alió&nbsp;Cornea, Cataract and Refractive Surgery Unit, Vissum (Grupo Miranza), Alicante, Spain J. L. Alió del Barrio&nbsp;J. L. Alió&nbsp;Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain Abstract The worldwide outbreak of the severe and acute respiratory coronavirus disease (COVID-19) caused by the coronavirus strain SARS-CoV-2 is currently the focal point of discussion due to the suffering this syndrome is causing to humanity. However, the ophthalmological implications of this syndrome has not yet been well described. Both eyes and tears as portals of entry and sources of contagion have been the subject of debate by many authors. The purpose of this review is to summarize the evidence currently available on COVID-19 and its ocular implications and manifestations, in both animals and humans, with the aim to facilitate prevention and educate the ophthalmological community on this subject. A review of the literature revealed that the results of some studies suggest that ocular symptoms commonly appear in patients with severe COVID-19 pneumonia and that it is possible to isolate the virus from the conjunctival sac of these patients. Conjunctivitis is not a common manifestation of the disease, but contact with infected eyes could be one route of transmission. Consequently, ophthalmologists need to have correct prevention strategies in place. Some guidelines regarding the prevention and management of ophthalmology clinics are reviewed. However, well-designed trials should be conducted to rule out other ocular manifestations that may result from COVID-19 infection and to understand the transmissio

The Value of Anterior Segment Optical Coherence Tomography in Different Types of Corneal Infections: An Update

Anterior segment optical coherence tomography (AS-OCT) is a modality that uses low-coherence interferometry to visualize and assess anterior segment ocular features, offering several advantages of being a sterile and noncontact modality that generates high-resolution cross-sectional images of the tissues. The qualitative and quantitative information provided by AS-OCT may be extremely useful for the clinician in the assessment of a wide spectrum of corneal infections, guiding in the management and follow-up of these patients. In clinical practice, infections are routinely evaluated with slit-lamp biomicroscopy, an examination and imaging modality that is limited by the physical characteristics of light. As a consequence, the depth of pathology and the eventually associated corneal edema cannot be accurately measured with the slit-lamp. Therefore, it represents a limit for the clinician, as in vivo information about corneal diseases and the response to treatment is limited. Resolution of corneal infection is characterized by an early reduction in corneal edema, followed by a later reduction in infiltration: both parameters can be routinely measured with standardized serial images by AS-OCT

Corneal transplantation outcomes after the extrusion of an intrastromal keratoprosthesis: a pilot study.

This short report includes 5 eyes of 5 patients (mean age 63.2 ± 12 years) who underwent a tectonic keratoplasty [deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PK)] in order to rehabilitate the eye after the extrusion of the non-perforating keratoprosthesis (Kpro) KeraKlear (KeraMed, USA). The non-perforating Kpro was extruded after a mean period of 21.4 ± 21.8 months due to melting. In two cases, the keratoplasty was performed the same day of the non-perforating Kpro removal due to a severe melting, while in the other three cases it was performed one to 3 months later. Two eyes received a DALK, but in 3 eyes a macroscopic Descemet membrane perforation forced the conversion into a PK. The mean follow-up period after the keratoplasty was 16.8 ± 6.6 months. No cases of rejection were recorded. All the 5 eyes achieved "anatomical success" (transparent graft, with no signs of infection or inflammation). Two eyes showed limited "functional success" because the achievement of the best visual potential was prevented by the development of glaucomatous optic atrophy during the follow-up period. In conclusion, this short report presents an unexpected success of a keratoplasty performed with a tectonic purpose after the extrusion of the non-perforating Kpro because the corneal graft remained transparent, without neovascularization or scarring during the follow-up period. This initial evidence shows some encouraging results regarding graft survival rate and the achievement of a useful visual rehabilitation with keratoplasty after a non-perforating Kpro failure instead of repeating the Kpro implantation

Retinal Optical Quality of Multifocal Refractive and Monofocal Intraocular Lenses

(1) Background: This study aimed to evaluate and compare the clinical optical image quality following implantation with different premium IOLs by the analysis of the point spread function (PSF) Strehl ratio using a Pyramidal WaveFront-based sensor (PWS) aberrometer at two different pupil sizes. (2) Methods: This study included 96 eyes of 70 patients implanted with: (1) 19 AcrySof SA60AT (control group); (2) 24 LENTIS Mplus LS-313 MF30; (3) 33 LENTIS Mplus LS-313 MF15; and (4) 20 Precizon Presbyopic. Main outcome measures were PSF Strehl ratio, PSF Strehl ratio excluding second-order aberrations (PSFw2), total root-mean-square (RMS), and low- and high-order aberrations’ RMS measured by PWS aberrometer. Results: SA60AT had the highest significant PSFw2 Strehl ratio at both 3- and 4-mm pupil size (0.41 ± 0.11 and 0.28 ± 0.07) followed by LENTIS Mplus 15 (group C, 0.35 ± 0.1 and 0.21 ± 0.06) and a near tie between LENTIS MPLUS 30 (group B, 0.27 ± 0.08 and 0.18 ± 0.06) and Precizon Presbyopic (group D, 0.27 ± 0.07 and 0.17 ± 0.04). MPlus MF15 was found to be significantly better than MPlus MF30 at both 3.00 mm (p p = 0.002). (4) Conclusions: The PSFw2 represents a new tool to objectively evaluate the far distance retinal image quality of multifocal IOLs, and the far distance clinical image quality parameters measured by PWS aberrometer differed significantly according to the technology of the implanted lens

Retinal Optical Quality of Multifocal Refractive and Monofocal Intraocular Lenses

(1) Background: This study aimed to evaluate and compare the clinical optical image quality following implantation with different premium IOLs by the analysis of the point spread function (PSF) Strehl ratio using a Pyramidal WaveFront-based sensor (PWS) aberrometer at two different pupil sizes. (2) Methods: This study included 96 eyes of 70 patients implanted with: (1) 19 AcrySof SA60AT (control group); (2) 24 LENTIS Mplus LS-313 MF30; (3) 33 LENTIS Mplus LS-313 MF15; and (4) 20 Precizon Presbyopic. Main outcome measures were PSF Strehl ratio, PSF Strehl ratio excluding second-order aberrations (PSFw2), total root-mean-square (RMS), and low- and high-order aberrations&rsquo; RMS measured by PWS aberrometer. Results: SA60AT had the highest significant PSFw2 Strehl ratio at both 3- and 4-mm pupil size (0.41 &plusmn; 0.11 and 0.28 &plusmn; 0.07) followed by LENTIS Mplus 15 (group C, 0.35 &plusmn; 0.1 and 0.21 &plusmn; 0.06) and a near tie between LENTIS MPLUS 30 (group B, 0.27 &plusmn; 0.08 and 0.18 &plusmn; 0.06) and Precizon Presbyopic (group D, 0.27 &plusmn; 0.07 and 0.17 &plusmn; 0.04). MPlus MF15 was found to be significantly better than MPlus MF30 at both 3.00 mm (p &lt; 0.0001) and 4.00 mm (p = 0.002). (4) Conclusions: The PSFw2 represents a new tool to objectively evaluate the far distance retinal image quality of multifocal IOLs, and the far distance clinical image quality parameters measured by PWS aberrometer differed significantly according to the technology of the implanted lens

morphogeometric and volumetric analysis

Purpose To assess the efficacy of morphogeometric and volumetric characterization of the cornea based on three-dimensional (3-D) modelling in diagnosis of subclinical keratoconus (KC).Methods Cross-sectional study. Ninety-three eyes with subclinical KC with a best spectacle-corrected distance visual acuity >= 20/20 (grade zero KC according to the RETICS classification) and 109 control eyes were included. Computer-based 3-D corneal morphogeometric model was generated using raw topographic data. Distance-, area- and volume-based parameters were used for statistical analysis. Distance parameters included deviation of anterior (D-apexant)/posterior (D-apexpost) apices and minimum thickness points (D-mctant, D-mctpost) from corneal vertex, and D-apexant-D-apexpost difference. Areal variables were derived from anterior (A(ant)) and posterior (A(post)) corneal surfaces, sagittal plane passing through corneal apices (A(apexant), A(apexpost)) and thinnest point (A(mctant), A(mctpost)). Total corneal volume (V-total) and volumetric distribution (with 0.1mm steps) centred to thinnest corneal point (VOLmct) and anterior (VOLaap)/posterior (VOLpap) apices comprised the volume-based parameters.Results In the subclinical KC group, all D values, D-apexant-D-apexpost difference, A(ant), A(post) and A(apexant) values were higher (p < 0.001), while A(apexpost), A(mctpost), V-total, VOLmct, VOLaap and VOLpap values were lower when compared to the control group (p < 0.001). Regression analysis-based formula correctly classified 96.8% of the eyes with subclinical KC and 94.5% of the normal ones (p < 0.0001).Conclusions Eyes with subclinical KC seem to represent asymmetrically displaced anterior and posterior corneal apex, corneal thinning and volume loss. 3-D morphogeometric and volumetric parameters and differentiation formula can be incorporated into topography software to detect subclinical KC with high sensitivity and specificity in clinical practice.C1 [Toprak, Ibrahim; Alio del Barrio, Jorge L.; Alio, Jorge L.] VISSUM, Dept Res & Dev, Alicante, Spain.[Toprak, Ibrahim] Pamukkale Univ, Fac Med, Dept Ophthalmol, Denizli, Turkey.[Cavas, Francisco; Velazquez, Jose S.] Tech Univ Cartagena, Dept Struct Construct & Graph Express, Cartagena, Spain.[Alio del Barrio, Jorge L.; Alio, Jorge L.] VISSUM, Cornea Cataract & Refract Surg Dept, Alicante, Spain.[Alio del Barrio, Jorge L.; Alio, Jorge L.] Miguel Hernandez Univ, Fac Med, Dept Pathol & Surg, Div Ophthalmol, Calle Cabanal 1,Edificio Vissum, Alicante 03016, Spain

Evidence of a Down Syndrome Keratopathy: A Three-Dimensional (3-D) Morphogeometric and Volumetric Analysis

The aim of this study was to investigate whether a different and abnormal corneal profile is present in Down syndrome (DS) by personalized three-dimensional (3D) modelling. This single-centre cross-sectional study included 43 patients with DS (43 eyes) and 58 age-sex-matched control subjects (58 eyes) with normal karyotype and topography. Refraction, central corneal thickness (CCT), aberrations (high-order, coma and spherical), asphericity and morphogeometric/volumetric parameters based on a 3D corneal model that was generated from raw topographical data were evaluated. Deviation of anterior/posterior apex (Dapexant/Dapexpost) and thinnest point (Dmctant/Dmctpost) from corneal vertex, anterior/posterior surface area (Aant/Apost), sagittal area passing through the anterior/posterior apex (Aapexant/Aapexpost) and thinnest point (Amctpost), total corneal volume (Vtotal) and volumetric progression for each 0.05 mm step of the radius value centred to the thinnest point (VOLMCT) and anterior/posterior apex (VOLAAP/VOLPAP) comprised the morphogeometric/volumetric parameters. In the DS group, 58.1% of the eyes presented abnormal topography. High-order and coma aberrations, asphericity, Dapexant, Aant, Apost and Aapexant were significantly higher, whereas CCT, Aapexpost, Amctpost, Vtotal, VOLAAP, VOLPAP and VOLMCT were lower in the DS group than in the control group (p apexpost did not differ between the groups (p > 0.05). This study demonstrates that corneas of the subjects with DS are different and more aberrated than those of normal age- and sex-matched non-DS controls. Anterior corneal apex appears to be displaced in DS even with normal topography, while posterior apex seems stable although topography is abnormal. These findings may help to modify our approach in the diagnosis of keratopathy in subjects with DS