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1.
Nat Commun ; 12(1): 1544, 2021 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-33750806

RESUMO

Electroretinogram examinations serve as routine clinical procedures in ophthalmology for the diagnosis and management of many ocular diseases. However, the rigid form factor of current corneal sensors produces a mismatch with the soft, curvilinear, and exceptionally sensitive human cornea, which typically requires the use of topical anesthesia and a speculum for pain management and safety. Here we report a design of an all-printed stretchable corneal sensor built on commercially-available disposable soft contact lenses that can intimately and non-invasively interface with the corneal surface of human eyes. The corneal sensor is integrated with soft contact lenses via an electrochemical anchoring mechanism in a seamless manner that ensures its mechanical and chemical reliability. Thus, the resulting device enables the high-fidelity recording of full-field electroretinogram signals in human eyes without the need of topical anesthesia or a speculum. The device, superior to clinical standards in terms of signal quality and comfortability, is expected to address unmet clinical needs in the field of ocular electrodiagnosis.


Assuntos
Lentes de Contato Hidrofílicas , Córnea/fisiologia , Eletrodiagnóstico/métodos , Sensação/fisiologia , Visão Ocular/fisiologia , Doenças da Córnea/diagnóstico , Eletrodiagnóstico/instrumentação , Eletrorretinografia/instrumentação , Eletrorretinografia/métodos , Humanos , Reprodutibilidade dos Testes , Dispositivos Eletrônicos Vestíveis
2.
Nature ; 585(7825): 383-389, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32939070

RESUMO

Insect eyes have an anti-reflective coating, owing to nanostructures on the corneal surface creating a gradient of refractive index between that of air and that of the lens material1,2. These nanocoatings have also been shown to provide anti-adhesive functionality3. The morphology of corneal nanocoatings are very diverse in arthropods, with nipple-like structures that can be organized into arrays or fused into ridge-like structures4. This diversity can be attributed to a reaction-diffusion mechanism4 and patterning principles developed by Alan Turing5, which have applications in numerous biological settings6. The nanocoatings on insect corneas are one example of such Turing patterns, and the first known example of nanoscale Turing patterns4. Here we demonstrate a clear link between the morphology and function of the nanocoatings on Drosophila corneas. We find that nanocoatings that consist of individual protrusions have better anti-reflective properties, whereas partially merged structures have better anti-adhesion properties. We use biochemical analysis and genetic modification techniques to reverse engineer the protein Retinin and corneal waxes as the building blocks of the nanostructures. In the context of Turing patterns, these building blocks fulfil the roles of activator and inhibitor, respectively. We then establish low-cost production of Retinin, and mix this synthetic protein with waxes to forward engineer various artificial nanocoatings with insect-like morphology and anti-adhesive or anti-reflective function. Our combined reverse- and forward-engineering approach thus provides a way to economically produce functional nanostructured coatings from biodegradable materials.


Assuntos
Bioengenharia , Córnea/anatomia & histologia , Córnea/fisiologia , Proteínas de Drosophila/química , Drosophila/anatomia & histologia , Proteínas do Olho/química , Nanoestruturas/química , Ceras/química , Adesividade , Análise de Variância , Animais , Córnea/química , Difusão , Drosophila/química , Drosophila/classificação , Drosophila/genética , Proteínas de Drosophila/deficiência , Proteínas de Drosophila/genética , Proteínas do Olho/genética , Técnicas de Silenciamento de Genes , Nanomedicina , Ligação Proteica , Engenharia de Proteínas , Dobramento de Proteína
3.
PLoS One ; 15(9): e0238395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966284

RESUMO

PURPOSE: The aim of the study was to investigate the effects of various anatomical structures on intraocular pressure (IOP) measurements obtained by the Corneal Visualization Scheimpflug Technology (Corvis ST), Goldmann applanation tonometer (GAT), and noncontact tonometer (NCT), as well as to assess the interchangeability among the four types of IOP measurement: IOP-GAT, IOP-NCT, IOP-Corvis, and biomechanically corrected IOP (bIOP-Corvis), with a particular focus on bIOP-Corvis. MATERIALS AND METHODS: We included 71 patients with primary open-angle glaucoma and assessed their IOP measurements obtained with the GAT, NCT, and Corvis ST using a repeated measures ANOVA, a paired t-test with Bonferroni correction, stepwise multiple regression analyses and Bland-Altman plots. RESULTS: IOP-GAT showed the highest values (13.5 ± 2.1 mmHg [mean ± standard deviation]), followed by IOP-NCT (13.2 ± 2.7 mmHg), IOP-Corvis (10.6 ± 2.8 mmHg), and bIOP-Corvis (10.0 ± 2.3 mmHg). With exceptions of bIOP-Corvis and IOP-GAT, all IOP variations were explained by regression coefficients involving the central corneal thickness. Bland-Altman plots showed a mean difference between IOP-GAT and the other IOP measurements (IOP-Corvis, bIOP-Corvis, and IOP-NCT), which were -2.90, -3.48, and -0.29 mmHg, respectively. The widths of the 95% limits of agreement between all pairs of IOP measurements were greater than 3 mmHg. CONCLUSION: IOP values obtained with the Corvis ST, NCT, and GAT were not interchangeable. The bIOP-Corvis measurement corrected for the ocular structure.


Assuntos
Glaucoma de Ângulo Aberto/fisiopatologia , Pressão Intraocular/fisiologia , Tonometria Ocular/métodos , Adulto , Idoso , Fenômenos Biomecânicos , Córnea/fisiologia , Córnea/fisiopatologia , Paquimetria Corneana , Feminino , Glaucoma de Ângulo Aberto/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Análise de Regressão , Tonometria Ocular/instrumentação , Tonometria Ocular/estatística & dados numéricos
4.
Curr Opin Ophthalmol ; 31(4): 225-233, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32398417

RESUMO

PURPOSE OF REVIEW: This review outlines ophthalmic diagnostic systems, which objectively evaluates the human visual system and its potential beyond that of Snellen acuity. RECENT FINDINGS: Advances in ophthalmic diagnostic systems have allowed for a deeper understanding of the optical principles of the human eye and have created the opportunity to evolve our current standards of vision assessment beyond Snellen acuity charts. Definitive comparative and validation trials will continue to be necessary in order for these advanced diagnostics to gain more widespread acceptance in the specialty, in addition to providing the guidance on the specific indications and utilities. SUMMARY: Advancements in wavefront analysis, light scatter measurements, and adaptive optics technologies can provide greater insight into an individual optical system's potential and irregularities. Modalities that test for anterior corneal surface and whole eye aberrations, light scatter and contrast sensitivity can be an excellent educational tool for our patients to help them better understand their visual dysfunction and can prove useful for medical or surgical decision-making.


Assuntos
Sensibilidades de Contraste/fisiologia , Córnea/fisiologia , Refração Ocular/fisiologia , Aberrações de Frente de Onda da Córnea/fisiopatologia , Humanos , Luz , Espalhamento de Radiação , Testes Visuais , Acuidade Visual/fisiologia
5.
Invest Ophthalmol Vis Sci ; 61(5): 25, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32416604

RESUMO

Purpose: Ophthalmic disorders are among the most prevalent Down syndrome (DS) comorbidities. Therefore, when studying mouse models of DS, ignoring how vision is affected can lead to misinterpretation of results from assessments dependent on the integrity of the visual system. Here, we used imaging and electroretinography (ERG) to study eye structure and function in two important mouse models of DS: Ts65Dn and Dp(16)1Yey/+. Methods: Cornea and anterior segment were examined with a slit-lamp. Thickness of retinal layers was quantified by optical coherence tomography (OCT). Eye and lens dimensions were measured by magnetic resonance imaging (MRI). Retinal vasculature parameters were assessed by bright field and fluorescent imaging, and by retinal flat-mount preparations. Ganzfeld ERG responses to flash stimuli were used to assess retinal function in adult mice. Results: Total retinal thickness is significantly increased in Ts65Dn and Dp(16)1Yey/+ compared with control mice, because of increased thickness of inner retinal layers, including the inner nuclear layer (INL). Increased retinal vessel caliber was found in both chromosomally altered mice when compared with controls. ERG responses in Ts65Dn and Dp(16)1Yey/+ mice showed subtle alterations compared with controls. These, however, seemed to be unrelated to the thickness of the INL, but instead dependent on the anesthetic agent used (ketamine, tribromoethanol, or urethane). Conclusions: We provide evidence of retinal alterations in Ts65Dn and Dp(16)1Yey/+ mice that are similar to those reported in persons with DS. Our ERG results are also a reminder that consideration should be given to the choice of anesthetic agents in such experiments.


Assuntos
Cromossomos de Mamíferos/genética , Modelos Animais de Doenças , Síndrome de Down/fisiopatologia , Retina/fisiopatologia , Animais , Córnea/fisiologia , Cruzamentos Genéticos , Síndrome de Down/genética , Eletrorretinografia , Feminino , Angiofluoresceinografia , Cristalino/fisiologia , Imagem por Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Midriáticos/administração & dosagem , Estimulação Luminosa , Pupila/efeitos dos fármacos , Vasos Retinianos/fisiopatologia , Microscopia com Lâmpada de Fenda , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia , Campos Visuais/fisiologia
6.
Curr Opin Ophthalmol ; 31(4): 234-240, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32452876

RESUMO

PURPOSE OF REVIEW: To review current and emerging methods and utilities of preoperative, intraoperative, and postoperative measurements of corneal biomechanics and their effects on refractive surgery decision-making. RECENT FINDINGS: Several recent clinical and preclinical studies have demonstrated the utility of corneal biomechanical analysis in refractive surgery. These studies focus on both screening surgical candidates for keratoconic disease as well as intraoperative and postoperative monitoring. The measurement of spatially resolved biomechanics is beginning to be studied in humans. SUMMARY: Clinically available screening methods combining corneal biomechanics with topographic and tomographic data provide increased utility when screening for keratoconic disorder. Spatially resolved measurement of corneal biomechanics holds great potential for preoperative, intraoperative, and postoperative evaluation of refractive surgery candidates as well as for more individualized procedures in the future.


Assuntos
Córnea/fisiologia , Elasticidade/fisiologia , Procedimentos Cirúrgicos Refrativos , Fenômenos Biomecânicos , Córnea/cirurgia , Topografia da Córnea , Técnicas de Imagem por Elasticidade , Humanos , Período Intraoperatório , Período Pós-Operatório , Período Pré-Operatório
7.
Am J Ophthalmol ; 216: 90-98, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32277940

RESUMO

PURPOSE: We sought to assess the agreement of ray-traced corneal power values by 3 Scheimpflug tomographers tp construct the corresponding arithmetic adjustment factor in comparison with an automated keratometer (IOLMaster) and a conventional Placido-based topographer (Allegro Topolyzer). DESIGN: Prospective reliability analysis. METHODS: A total of 74 eyes from 74 healthy subjects who underwent corneal power measurements using Pentacam, Sirius, Galilei, IOLMaster, and Allegro Topolyzer were included. Ray-traced corneal power values, such as total corneal refractive power (TCRP), mean pupil power (MPP), total corneal power (TCP), mean keratometry (Km), and simulated keratometry (SimK) were recorded respectively and analyzed using one-way analysis of variance (ANOVA) and Bland-Altman plots. RESULTS: Among the 3 ray-traced corneal power values, TCRP and MPP did not differ significantly (P = 0.81), whereas TCP presented a slightly significant larger value (P < 0.001). Compared to Km or SimK, corneal power measurements by the ray tracing method exhibited significantly lower values (P < 0.001). Bland-Altman plots disclosed that the 3 Scheimpflug tomographers showed similar 95% limits of agreement after arithmetic adjustment compared with Km (-0.40 to 0.40 D, -0.39 to 0.39 D, and -0.35 to 0.34 D) or SimK (-0.50 to 0.51 D, -0.43 to 0.42 D, and -0.46 to 0.46 D). CONCLUSIONS: Ray-traced corneal power values obtained using 3 Scheimpflug tomographers with default diameter settings were similar, indicating that they could be used interchangeably in daily clinical practice. The 3 Scheimpflug tomographers were satisfactory in agreement after arithmetical adjustment compared with conventional automated keratometer or Placido-based topographer.


Assuntos
Córnea/fisiologia , Fotografação/instrumentação , Refração Ocular/fisiologia , Adulto , Córnea/diagnóstico por imagem , Topografia da Córnea/instrumentação , Feminino , Voluntários Saudáveis , Humanos , Masculino , Estudos Prospectivos , Reprodutibilidade dos Testes , Tomografia/instrumentação , Adulto Jovem
8.
J Craniofac Surg ; 31(5): e459-e461, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32310879

RESUMO

PURPOSE: To determine the relationship between visual acuity and corneal curvature change in children after epiblepharon correction surgery by corneal topography. METHODS: The authors retrospectively reviewed the data of 62 children (121 eyes) who had epiblepharon surgery. The authors measured keratometric values of corneal curvature for 2 corneal zones: central 3 and 5 mm zone. Two zones were classified into 4 areas, including nasal, superior, temporal, and inferior area. Visual acuity and keratometric values were estimated preoperatively and at 1, 3, and 6 months postoperatively. The authors analyzed the correlation between visual acuity and corneal curvature change in 4 areas of the 2 zones. RESULTS: There were statistically significant differences between preoperative and postoperative visual acuity 1 month after surgery. At postoperative 3 months, the inferior and superior areas of the 3 mm corneal zone were much flatter than before surgery (P < 0.05). Corneal curvature only at the inferior area of the 3 mm zone had significantly a negative correlation with postoperative visual acuity at 3 and 6 months (r =  -0.275, P = 0.02 and r = -0.351, P = 0.01, respectively). However, visual acuity had no significant correlation with corneal curvature change in any of the areas of the 5-mm corneal zone. CONCLUSIONS: The authors found that corneal curvature has significantly become flattened in the superior and inferior areas of the 3 mm corneal zone, postoperatively. Furthermore, inferior area in the 3 mm corneal zone affected only on the visual acuity improvement after postoperative 3 months.


Assuntos
Córnea/fisiologia , Córnea/cirurgia , Pálpebras/cirurgia , Acuidade Visual , Criança , Pré-Escolar , Topografia da Córnea , Feminino , Humanos , Masculino , Período Pós-Operatório , Estudos Retrospectivos
9.
Invest Ophthalmol Vis Sci ; 61(4): 19, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32298437

RESUMO

Purpose: To characterize the corneal biomechanical properties of glaucoma eyes by comparing the dynamic Scheimpflug biomechanical parameters between untreated glaucoma and control eyes. Methods: Cross-sectional observational data of dynamic Scheimpflug analyzer (Corvis ST) examinations were retrospectively collected from 35 eyes of 35 consecutive patients with untreated normal tension glaucoma and 35 eyes of 35 healthy patients matched on age and IOP. Ten biomechanical parameters were compared between the two groups using multivariable models adjusting for IOP, central corneal thickness, age, and axial length. The Benjamini-Hochberg method was used to correct for multiple comparison. Results: In multivariable models, glaucoma was associated with smaller applanation 1 time (P < 0.001, coefficient = -0.5865), applanation 2 time (P = 0.012, coefficient = -0.1702), radius (P = 0.006, coefficient = -0.5447), larger peak distance (P = 0.011, coefficient = 0.1023), deformation amplitude ratio at 1 mm (P < 0.001, coefficient = 0.072), and integrated radius (P < 0.001, coefficient = 1.094). These associations consistently indicate greater compliance of the cornea in glaucoma eyes. Conclusions: Untreated normal tension glaucoma eyes were more compliant than healthy eyes. The greater compliance (smaller stiffness) of normal tension glaucoma eyes may increase the risk of optic nerve damage. These results suggest the relevance of measuring biomechanical properties of glaucoma eyes.


Assuntos
Córnea/fisiologia , Elasticidade/fisiologia , Glaucoma de Ângulo Aberto/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Comprimento Axial do Olho , Fenômenos Biomecânicos , Estudos de Casos e Controles , Córnea/diagnóstico por imagem , Estudos Transversais , Feminino , Glaucoma de Ângulo Aberto/diagnóstico por imagem , Humanos , Pressão Intraocular/fisiologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Campos Visuais/fisiologia , Adulto Jovem
10.
Anim Sci J ; 91(1): e13373, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32301197

RESUMO

The difference in the frequency of the occurrence of reflexes/reactions in 355 cows (average weight 505.5 ± 7.9 kg) and 262 bulls (average weight 735.6 ± 8.4 kg) following stunning with a Matador SS 3,000 B trigger-activated captive bolt gun (Termet) was determined. The stun shot more than 2 cm from the ideal position was found in 79.6% of animals. Vocalization, corneal reflex, rhythmic breathing, blinking, eyeball rotation and the absence of tongue protrusion occurred more frequently in bulls (p < .05). Spontaneous limb movements and nystagmus occurred more frequently in cows (p < .05). No difference between bulls and cows was determined in the occurrence of a response to painful stimuli or attempts to regain normal posture. No dependency was determined between the frequency of the occurrence of a reflex/reaction and the distance of the stun shot from the ideal point on the skull for any of the monitored signs. This study shows that the occurrence of reflexes/reactions following the stunning of cattle with a captive bolt is not only dependent on the position of the shot if placed within a 9 cm radius from the ideal point on the cattle skull.


Assuntos
Matadouros , Criação de Animais Domésticos/métodos , Bovinos/fisiologia , Eletrochoque/efeitos adversos , Eletrochoque/veterinária , Reflexo/fisiologia , Animais , Piscadela/fisiologia , Córnea/fisiologia , Movimentos Oculares/fisiologia , Feminino , Masculino , Respiração , Vocalização Animal/fisiologia
11.
PLoS One ; 15(4): e0230589, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32240192

RESUMO

PURPOSE: To test the repeatability and reproducibility of the topography module in posterior segment spectral domain optical coherence tomography with Revo NX (new device) and to compare keratometry values obtained by a Scheimpflug tomography (Galilei G6) and a swept source OCT (Casia 2). METHODS: In this prospective study, healthy subjects with nonoperated eyes had their central corneal thickness (CCT), anterior and posterior K1/K2 corneal power measured with the new device. Two operators made 6 measurements on the new device to check intraobserver repeatability and reproducibility, and measurement on Casia 2 and Galilei G6. Bland-Altman plots were used to assess the agreement between the devices for each analyzed variable. RESULTS: 94 eyes (94 patients) were studied. All devices produced significantly different mean CCT, the highest for Galilei 569.13±37.58 µm followed by Casia 545.00 ±36.15 µm and Revo 537.39±35.92 µm. The mean anterior K1 was 43.21 ± 1.37 for Casia 2 43.21 ± 1.55 for Revo NX and 43.19 ± 1.39 for Galilei G6, and the differences were insignificant p = 0.617. The posterior K1 for Revo NX was -5.77 ± 0.25 whereas for Casia 2 it was -5.98±0.22 and for Galilei G6-6.09±0.28 D p< 0.0001. The Revo NX showed intraclass correlation coefficient ranging from 0.975 for the posterior K2 surface, and 0.994 for anterior K1 and 0.998 for CCT. CONCLUSIONS: Revo NX is independent of the user and offers a high level of repeatability for the anterior and posterior cornea. The wide range of differences between the devices suggests they should not be used interchangeably.


Assuntos
Córnea/anatomia & histologia , Córnea/fisiologia , Paquimetria Corneana/métodos , Topografia da Córnea/métodos , Tomografia de Coerência Óptica/métodos , Adulto , Feminino , Humanos , Masculino , Estudos Prospectivos , Reprodutibilidade dos Testes
12.
PLoS One ; 15(3): e0230119, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163466

RESUMO

OBJECTIVE: To elucidate the relationship between lipid layer thickness (LLT), incomplete blinking rate and tear film stability in patients with different myopia degrees after small-incision lenticule extraction (SMILE) and to determine whether there is a difference in the prevalence of dry eye disease (DED) after SMILE among patients with different myopia degrees. METHODS: Fifty patients (100 eyes) were enrolled in this study; they were divided into 3 groups according to the degree of spherical refraction: a low-myopia group (LMG; spherical refraction ≤-3.00 D, 20 eyes), a moderate-myopia group (MMG; -3.00 D < spherical refraction <-6.00 D, 40 eyes), and a high-myopia group (HMG; spherical refraction ≧-6.00 D, 40 eyes). Testing indicators included the ocular surface disease index (OSDI), fluorescein tear film breakup time (FBUT), corneal fluorescence staining (CFS), the Schirmer test (SI), lipid layer thickness (LLT), blink rate (BR) per 20 seconds, incomplete blinking rate, noninvasive keratograph assessment of first and average tear film breakup time (NIKBUTf, NIKBUTav), and tear meniscus height (TMH). Each indicator was evaluated preoperatively and postoperatively at 1 w, 1 mo and 3 mo. RESULTS: The mean age was 29.12±5.95 years. There were no significant differences among the three groups (p>0.05), except preoperative age (p = 0.006). There were significant differences in the FBUT among the three groups at postoperative 1 w and 1 mo (p<0.05). There were significant differences in the incomplete blinking rate and FBUT between the LMG and the HMG at postoperative 1 mo (p<0.05). The number of first tear film breakup points located beyond the 6 mm diameter of the cornea was higher in the HMG than in the other groups. The prevalence of DED in the LMG, the MMG, the HMG was 15%, 8% and 23%, respectively, at 1 w postoperative and 30%, 45% and 53%, respectively, at postoperative 1 mo. The change in LLT was significantly correlated with the changes in FBUT (r = 0.408, p<0.001) and incomplete blinking rate (r = -0.266, p = 0.007). The change in OSDI was negatively correlated with the change in SI (r = -0.502, p = 0.000). CONCLUSIONS: The changes in LLT and incomplete blinking rate decreased the stability of the tear film. The changes in LLT, FBUT and incomplete blinking rate differed postoperatively with different myopia degrees. The prevalence of DED was higher in the HMG than in the other two groups.


Assuntos
Piscadela/fisiologia , Córnea/cirurgia , Lipídeos/química , Miopia/patologia , Lágrimas/fisiologia , Adulto , Córnea/fisiologia , Síndromes do Olho Seco/complicações , Síndromes do Olho Seco/epidemiologia , Síndromes do Olho Seco/patologia , Feminino , Humanos , Lasers de Excimer , Masculino , Microcirurgia/métodos , Miopia/complicações , Período Pós-Operatório , Prevalência , Índice de Gravidade de Doença
13.
Zhonghua Yan Ke Za Zhi ; 56(2): 103-109, 2020 Feb 11.
Artigo em Chinês | MEDLINE | ID: mdl-32074820

RESUMO

Objective: To investigate the application value of Pentacam combined with Corvis ST in evaluation of the changes of corneal biomechanics after femtosecond laser small incision lenticule extraction (SMILE) in Chinese myopia with an irregular cornea. Methods: The clinical records for 104 eyes of 57 patients who received SMILE in the Refractive Center of Beijing Tongren Hospital during January 2018 and May 2018 were collected. According to the keratoconus severity index (KSI), they were divided into two groups: regular corneal group (KSI<15%) and irregular corneal group (KSI: 15% to 25%). In both groups, the anterior corneal surface radius curvature was>7.25 mm (K<46.50 diopters), the posterior corneal surface radius curvature was>5.90 mm, the thinnest pachymetry was>490 µm, and best corrected visual acuity was ≥1.0. The vision, refraction, and corneal biomechanics before and after SMILE were assessed. The Topographic and Biomechanics Index (TBI) was analyzed by Pentacam combined with Corvis ST. Results: Before SMILE, the Corvis Biomechanical Index (CBI), TBI, and Belin/Ambrósio Deviation Normalized Index (BADD) of the irregular corneal group were significantly higher (t=-2.17, -6.78, -4.37, P<0.05) than the regular corneal group, while the stiffness parameter (SPA1) was significantly lower (t=2.58, P=0.011) compared to the regular corneal group (P<0.05). In the irregular group, the TBI was (0.28±0.2); the maximum value was 0.03, and the minimum value was 0.43. The CBI was (0.09±0.21); the maximum value was 0.00, and the minimum value was 0.54. The BADD was (1.33±0.47); the maximum value was 0.42, and the minimum value was 2.26. In the regular group, the TBI was (0.05±0.08); the maximum value was 0.00, and the minimum value was 0.20. The CBI was (0.01±0.03); the maximum value was 0.00, and the minimum value was 0.17. The BADD was (0.92±0.46); the maximum value was 0.00, and the minimum value was 1.64. There was no significant difference between two groups in age (t=0.20, P=0.508), central corneal thickness (t=1.64, P=0.104), biomechanical corrected IOP (t=0.73, P=0.468), max inverse radius (t=-0.24, P=0.815), spherical equivalent (t=-0.97, P=0.335), and best corrected visual acuity (t=0.21, P=0.833). After SMILE, the deformation amplitude in the irregular group was significantly higher at 1 month and 3 months (t=-3.13, -3.09, P<0.05). The irregular group had a significantly higher deformation amplitude ratio at 1 week, 1 month, and 1 year (t=-2.72, -3.39, -2.51, P<0.05). The SPA1 in the irregular group was significantly lower than the regular group at 1 week, 1 month, and 3 months (t=2.11, 2.73, 3.70, P=0.335, 0.010,<0.001). The changes of deformation amplitude (t=0.50, -1.10, -0.73, 2.12, P>0.05), max inverse radius (t=-1.52, -1.41, 0.01, -0.79, P>0.05), and SPA1(t=0.89, 0.90, 1.12, 0.90, P>0.05) after SMILE were similar between the irregular and regular groups, except that at 1 month after SIMILE, the deformation amplitude ratio changed more significantly in the irregular group (t=-3.01, P=0.003). Conclusions: The changes of corneal biomechanics in the groups of regular cornea and irregular cornea were stable with no significant difference during 1 year of post-SMILE. The diagnosis based on the corneal topography and corneal biomechanics is of certain significance for the screening of early keratoconus before keratorefractive surgery. (Chin J Ophthalmol, 2020, 56:103-109).


Assuntos
Córnea , Ceratocone , Miopia , Fenômenos Biomecânicos , Córnea/fisiologia , Córnea/cirurgia , Substância Própria , Topografia da Córnea , Humanos , Acuidade Visual
14.
Sci Rep ; 10(1): 2357, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32047218

RESUMO

Orthokeratology (Ortho-K) works to reshape cornea and is the only non-surgical way to enable vision without corrective aids. However, its effect is only temporary, and successful stabilization requires ongoing Ortho-K wear to maintain the reshaping effect. Corneal crosslinking (CXL) is a commonly-used technique in clinical practice to stabilize corneal shape in keratoconic eyes. However, whether or not CXL can stabilize corneal shape after Ortho-K in normal cornea has not been reported. Therefore, this proof-of-concept study using 2 rhesus monkeys aimed to determine the efficacy of the combined procedure. One monkey wore Ortho-K bilaterally for 24 hours, and the other from 6 pm to 8 am for 7 days. The left eyes of both monkeys underwent CXL after Ortho-K while the contralateral eye served as control. Results showed a gradual regression of corneal shape in all eyes with or without CXL. However, eyes underwent CXL regressed more slowly than the control eyes. The control eyes and the CXL treatment eye in the 7-day Ortho-K monkey regressed completely at last, while the CXL treatment eye in the 24 h Ortho-K monkey maintained a corneal flattening of -1.48 D 27 days after procedure. These findings suggest CXL can slow the regression of Ortho-K for a short duration, but cannot sustain its effect according to the current protocol.


Assuntos
Córnea/anatomia & histologia , Procedimentos Ortoceratológicos/métodos , Animais , Córnea/fisiologia , Macaca mulatta , Masculino , Refração Ocular
15.
PLoS One ; 15(2): e0228920, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053692

RESUMO

The purpose of this study was to ascertain the relationships between the amplitude of the corneal pulse (CP) signal and the parameters of corneal biomechanics during ex-vivo intraocular pressure (IOP) elevation experiments on porcine eyes with artificially induced ocular pulse cycles. Two experiments were carried out using porcine eyes. In the first one, a selected eye globe was subjected to three IOP levels (15, 30 and 45 mmHg), where changes in physical ocular pulse amplitude were controlled by infusion/withdrawal volumes (ΔV). In the second experiment, six eyes were subjected to IOP from 15 mmHg to 45 mmHg in steps of 5 mmHg with a constant ΔV, where corneal deformation parameters were measured using Corvis ST. In both experiments, at each IOP, the CP and IOP signals were acquired synchronically using a non-contact ultrasonic distance sensor and a pressure transmitter, respectively. Based on the amplitudes of the CP and IOP signals ocular pulse based corneal rigidity index (OPCRI) was calculated. Results indicate positive correlations between ΔV and the physical ocular pulse amplitude, and between ΔV and the corneal pulse amplitude (both p < 0.001). OPCRI was found to increase with elevated IOP. Furthermore, IOP statistically significantly differentiated changes in OPCRI, the amplitudes of CP and IOP signals and in most of the corneal deformation parameters (p < 0.05). The partial correlation analysis, with IOP as a control variable, revealed a significant correlation between the length of the flattened cornea during the first applanation (A1L) and the corneal pulse amplitude (p = 0.002), and between A1L and OPCRI (p = 0.003). In conclusion, this study proved that natural corneal pulsations, detected with a non-contact ultrasonic technique, reflect pressure-volume dynamics and can potentially be utilized to assess stiffness of the cornea. The proposed new rigidity index could be a simple approach to estimating corneal rigidity.


Assuntos
Córnea/fisiologia , Pressão Intraocular/fisiologia , Tonometria Ocular/métodos , Animais , Fenômenos Biomecânicos , Elasticidade , Glaucoma , Projetos Piloto , Suínos
16.
PLoS One ; 15(1): e0227638, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31935241

RESUMO

PURPOSE: To compare the accuracy of the five commonly used intraocular lens (IOL) calculation formulas integrated to a swept-source optical biometer, the IOLMaster 700, and evaluate the extent of bias within each formula for different ocular biometric measurements. METHODS: The study included patients undergoing cataract surgery with a ZCB00 IOL implant, using IOLMaster 700 optical biometry. A single eye per patient was included in the final analysis for a total of 324 cases. The SRK/T, Hoffer Q, Haigis, Holladay 2, and Barrett Universal II formulas were evaluated. The correlations between the refractive prediction errors calculated using the five formulas and ocular dimensions such as axial length (AL), anterior chamber depth (ACD), corneal power, and lens thickness (LT) were analyzed. RESULTS: There were significant differences in the median absolute error predicted by the five formulas after the adjustment for mean refractive prediction errors to zero (P = 0.038). The Barrett Universal II formula had the lowest median absolute error (0.263) and resulted in a higher percentage of eyes with prediction errors within ±0.50 D, ±0.75 D, and ±1.00 D (all P < 0.050). The refractive errors predicted by only the Barrett formula showed no significant correlation with the ocular dimensions: AL, ACD, corneal power, and LT. CONCLUSIONS: Overall, the Barrett Universal II formula, integrated to a swept-source optical biometer had the lowest prediction error and appeared to have the least bias for different ocular biometric measurements for the ZCB00 IOL.


Assuntos
Biometria/métodos , Lentes Intraoculares/normas , Testes Visuais/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Comprimento Axial do Olho , Extração de Catarata/métodos , Córnea/fisiologia , Feminino , Humanos , Implante de Lente Intraocular/métodos , Cristalino/fisiologia , Masculino , Pessoa de Meia-Idade , Miopia/cirurgia , Facoemulsificação/métodos , Registros , Refração Ocular/fisiologia , Erros de Refração/diagnóstico , Procedimentos Cirúrgicos Refrativos/métodos , Reprodutibilidade dos Testes , República da Coreia , Estudos Retrospectivos , Acuidade Visual/fisiologia
17.
PLoS One ; 15(1): e0228267, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31995608

RESUMO

PURPOSE: To investigate changes in intraocular pressure (IOP) and axial length (AL) on the ascent to high altitude from Beijing to Lhasa. PATIENTS AND METHODS: Twenty volunteers (17 men, 3 women) who had been sent to work in Lhasa, Tibet for more than 6 months were enrolled. One of their journeys from Beijing to Lhasa was chosen as the time for the examination. IOP, AL, corneal curvature (K), and blood pressure (BP) were measured in Beijing (altitude 43 m) and Lhasa (altitude 3658 m). Their first examination was conducted at least 1 day before arriving in Lhasa and the second examination after they had stayed in Lhasa for 7 days. The data from the highland and lowland examinations were analyzed with a paired-sample T test and Pearson's correlation coefficient was calculated for the association between IOP and average BP. RESULTS: The mean IOP was 12.65±2.34 mmHg in Beijing and 14.85±3.1 mmHg in Lhasa. The mean AL was 24.61±1.50mm in Beijing, and 24.98±1.45 mm in Lhasa. The IOP and AL showed a significant elevation in highland compared with lowland (P<0.05). The mean K was 43.58±2.25 D in Beijing and 43.56±2.21 D in Lhasa and no significant difference was found in this study (P>0.05). A positive correlation between variance of IOP and ACD was found (r = 0.475, P<0.05) and no correlation between IOP and average BP was noted. CONCLUSIONS: High altitude may lead to a small but significant change in IOP and axial length. However, the shape of the corneal surface was not influenced by the hypobaric and hypoxic conditions.


Assuntos
Aclimatação , Altitude , Córnea/anatomia & histologia , Pressão Intraocular , Aclimatação/fisiologia , Adulto , Doença da Altitude/fisiopatologia , Câmara Anterior/anatomia & histologia , Câmara Anterior/fisiologia , Pequim , Pressão Sanguínea/fisiologia , Córnea/fisiologia , Feminino , Humanos , Pressão Intraocular/fisiologia , Masculino , Tibet , Fatores de Tempo , Corpo Vítreo/anatomia & histologia , Corpo Vítreo/fisiologia
18.
PLoS One ; 15(1): e0224824, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31914133

RESUMO

BACKGROUND: To develop a method, using current clinical instrumentation, to estimate the Young's modulus of the human cornea in vivo. METHODS: Central corneal curvature (CCC), central corneal thickness(CCT), intraocular pressure (IOP) was measured with the Goldmann tonometer (IOPG) and the Pascal Dynamic Corneal Tonometer(PDCT) in one eye of 100 normal young human subjects (21.07 ± 2.94 years) in vivo. The Orssengo and Pye algorithm was used to calculate the Young's modulus of the corneas of these subjects. RESULTS: The Young's modulus(E) of the corneas of the subjects using the PDCT and IOPG results (Ecalc) was 0.25 ± 0.10MPa, and without the PDCT results (Eiopg) was 0.29 ± 0.06MPa. The difference in these results is due to the difference in tonometry results between the two instruments, as the mean PDCT result for the subjects was 16.89 ± 2.49mmHg and the IOPG result 15.06 ± 2.71mmHg. E was affected by the CCC of the subjects but more particularly by the CCT and IOP measurements. Corneal stiffness results are also presented. CONCLUSION: Two methods have been developed to estimate the Young's modulus of the human cornea in vivo using current clinical instrumentation. One method (Ecalc) is applicable to the general corneal condition, and Eiopg to the normal cornea, and these results can be used to calculate corneal stiffness.


Assuntos
Córnea/diagnóstico por imagem , Paquimetria Corneana/métodos , Elasticidade/fisiologia , Tonometria Ocular/métodos , Adulto , Algoritmos , Córnea/fisiologia , Doenças da Córnea/diagnóstico , Doenças da Córnea/diagnóstico por imagem , Doenças da Córnea/fisiopatologia , Feminino , Humanos , Pressão Intraocular/fisiologia , Masculino , Hipertensão Ocular/diagnóstico , Hipertensão Ocular/diagnóstico por imagem , Hipertensão Ocular/fisiopatologia
19.
PLoS One ; 15(1): e0227771, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31951635

RESUMO

PURPOSE: Ocular somatosensory-autonomic reflexes play critical roles in maintaining homeostasis of the eye. The purpose of this study was to investigate the pupil response to nociceptive corneal stimuli. METHODS: A Waterloo-Belmonte pneumatic esthesiometer was used to determine detection thresholds and randomly deliver mechanical and chemical stimuli from levels of detection threshold to twice the threshold in 50% steps to the central cornea of 15 healthy subjects. For each stimulus, imaging of the stimulated/unstimulated eye was performed using two modified/calibrated Logitech c920 digital cameras for 4 seconds each, pre/post stimulus capture. The data were processed with a custom segmentation algorithm to help identify the pupils and pupil diameter was measured using ImageJ software. Pupil dilation response differences between the ipsi- and contralateral eye was analyzed using dependent t-tests. The effect of stimulus intensity, modality and sex of subjects were analyzed using repeated measures. RESULTS: In mechanical and chemical stimulation experiments, there was no difference in pupil responses between the stimulated eye and the unstimulated eye, (all dependent T-test p > 0.05). On average, pupil diameter increased from baseline as the corneal stimulus intensity increased. This happened regardless of whether mechanical or chemical stimulation occurred (ANOVA p < 0.05). At 200% threshold, pupil diameter was greater than at all stimulus intensities (Tukey HSD, all p < 0.05). Based on stimulus intensity, females had greater pupil diameters than males at levels of 150% threshold and 200% threshold (ANOVA p < 0.05, all Tukey HSD p < 0.05). CONCLUSION: This study serves as a basis for the characterization of the local stimulus-response neural circuitry relating nociceptive stimuli to autonomic responses and in combination with our work on completely separate autonomic circuits of bulbar conjunctival vessel dilation and reflex tearing suggests that the monotonic measurements of redness, tearing and pupils provide accurate, separable responses that reflect painful stimulus intensity.


Assuntos
Córnea/fisiologia , Nociceptividade , Pupila/fisiologia , Reflexo Pupilar , Adulto , Dióxido de Carbono/metabolismo , Feminino , Humanos , Masculino , Estimulação Física , Limiar Sensorial , Adulto Jovem
20.
Transplantation ; 104(6): 1159-1165, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31895867

RESUMO

BACKGROUND: Corneal storage for the very long term, without degradation, would make it possible to optimize a very limited resource worldwide. We previously demonstrated the superiority, compared to conventional 4-week passive organ culture (OC), of an active storage machine (ASM) that restores intraocular pressure and medium renewal. Here, we investigate eye banking for up to 3 months. METHODS: In a randomized preclinical trial with 24 paired corneas, 1 was stored in OC and the other in ASM, using the same medium. Assessments were done on the second day and at 3 months: endothelial cell density (ECD in cells/mm), corneal transparency and thickness. At day 86, OC corneas were deswelled in a common hyperosmotic medium, but not the ASM corneas, which had remained thin. In addition, at day 88, viable ECD was measured using a live/dead assay, and endothelial expression of Na/K ATPase, Cox IV, ZO-1, N-CAM, and CD166 was observed. RESULTS: The ASM extended storage to 3 months with unprecedented endothelial cell quality: no OC corneas remained suitable for transplantation, but one-third of ASM corneas were compliant (ECD > 2000/mm). Given that corneas with ECD > 1600/mm were also usable for emergency, 58% of ASM corneas were usable versus 33% in OC. EC survival was 53% higher in ASM (P < 0.001), structural and functional proteins of ECs were much better preserved in ASM, and it prevented the constant major edema of OC. CONCLUSIONS: By extending graft survival to 3 months, the ASM will optimize eye banking and open up new perspectives in experimental research.


Assuntos
Córnea/fisiologia , Transplante de Córnea , Células Endoteliais/fisiologia , Bancos de Olhos/métodos , Preservação de Órgãos/instrumentação , Idoso , Idoso de 80 Anos ou mais , Contagem de Células , Córnea/citologia , Feminino , Humanos , Pressão Intraocular/fisiologia , Masculino , Pessoa de Meia-Idade , Soluções para Preservação de Órgãos , Estudos Prospectivos , Distribuição Aleatória , Fatores de Tempo
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