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1.
J. optom. (Internet) ; 17(2): [100485], Abr-Jun, 2024. tab, ilus
Artículo en Inglés | IBECS | ID: ibc-231620

RESUMEN

Purpose: To study topographic epithelial and total corneal thickness changes in myopic subjects undergoing successful orthokeratology treatment in connection with the objective assessment of contact lens decentration. Methods: A prospective-observational and non-randomized study in 32 Caucasian myopic eyes undergoing Ortho-k for 3 months. Total, epithelial, and stromal thicknesses were studied before and after Ortho-k treatment, using optical coherence tomography with anterior segment application software. Central, paracentral, and mid-peripheral values are taken along 8 semi-meridians. Results: The central average total corneal thickness was 4.72 ± 1.04 μm thinner after Ortho-K. The paracentral corneal thickness showed no significant changes (p = 0.137), while the mid-peripheral corneal thickness was increased by 3.25 ± 1.6 μm associating this increase exclusively to the epithelial plot (p<0.001). When lens centration was assessed, a lens fitting decentration less than 1.0 mm was found for the whole sample, predominantly horizontal-temporal (87.5%) and vertical-inferior (50%) decentring. Corneal topographical analysis revealed a horizontal and vertical epithelial thickness asymmetric change profile with paracentral temporal thinnest values, and mid-peripheral nasal thickest values. Conclusions: The present study found a central corneal thinning induced by Ortho-k lenses in subjects with moderate myopia, only associated with a change in epithelial thickness, as well as mid-peripheral thickening, that seems to be mainly epithelial in origin. The authors also found a tendency of contact lens decentration toward temporal and inferior areas conditioning an asymmetric epithelial redistribution pattern.(AU)


Asunto(s)
Humanos , Masculino , Femenino , Visión Ocular , Miopía , Cristalino , Procedimientos de Ortoqueratología , Sustancia Propia , Tomografía de Coherencia Óptica , Estudios Retrospectivos , Optometría , Oftalmología , Estudios Prospectivos
2.
Mol Vis ; 30: 37-48, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38586607

RESUMEN

Purpose: Congenital cataract affects 1-15 per 10,000 newborns worldwide, and 20,000-40,000 children are born every year with developmental bilateral cataracts. Mutations in the crystallin genes are known to cause congenital cataracts. Crystallins, proteins present in the eye lens, are made up of four Greek key motifs separated into two domains. Greek key motifs play an important role in compact folding to provide the necessary refractive index and transparency. The present study was designed to understand the importance of the fourth Greek key motif in maintaining lens transparency by choosing a naturally reported Y134X mutant human γD- crystallin in a Danish infant and its relationship to lens opacification and cataract. Methods: Human γD-crystallin complementary DNA (cDNA) was cloned into the pET-21a vector, and the Y134X mutant clone was generated by site-directed mutagenesis. Wild-type and mutant proteins were overexpressed in the BL21 DE3 pLysS cells of E. coli. Wild-type protein was purified from the soluble fraction using the ion exchange and gel filtration chromatography methods. Mutant protein was predominantly found in insoluble fraction and purified from inclusion bodies. The structure, stability, aggregational, and amyloid fibril formation properties of the mutant were compared to those of the wild type using the fluorescence and circular dichroism spectroscopy methods. Results: Loss of the fourth Greek key motif in human γD-crystallin affects the backbone conformation, alters the tryptophan micro-environment, and exposes a nonpolar hydrophobic core to the surface. Mutant is less stable and opens its Greek key motifs earlier with a concentration midpoint (CM) of unfolding curve of 1.5 M compared to the wild type human γD-crystallin (CM: 2.5 M). Mutant is capable of forming self-aggregates immediately in response to heating at 48.6 °C. Conclusions: Loss of 39 amino acids in the fourth Greek key motif of human γD-crystallin affects the secondary and tertiary structures and exposes the hydrophobic residues to the solvent. These changes make the molecule less stable, resulting in the formation of light-scattering particles, which explains the importance of the fourth Greek key in the underlying mechanism of opacification and cataract.


Asunto(s)
Catarata , Cristalino , gamma-Cristalinas , Recién Nacido , Niño , Humanos , Escherichia coli/genética , Escherichia coli/metabolismo , gamma-Cristalinas/química , Cristalino/metabolismo , Catarata/genética , Catarata/metabolismo , Mutación , Mutagénesis Sitio-Dirigida
3.
Invest Ophthalmol Vis Sci ; 65(4): 4, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38558092

RESUMEN

Purpose: To examine lens phenotypic characteristics in ßA3ΔG91 mice and determine if ßA3ΔG91 affects autophagy in the lens. Methods: We generated a ßA3ΔG91 mouse model using CRISPR/Cas9 methodology. Comparative phenotypic and biochemical characterizations of lenses from postnatal day 0 (P0), P15, and 1-month-old ßA3ΔG91 and wild-type (WT) mice were performed. The methodologies used included non-invasive slit-lamp examination, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot, and immunohistochemical (IHC) analyses to determine the levels of autophagy-related genes and proteins. Transmission electron microscopy (TEM) analysis of lenses was performed to assess organelle degradation and the presence of autophagic vesicles. TUNEL staining was used to determine apoptosis in the lens. Results: Relative to WT lenses, 1-month-old ßA3ΔG91 mice developed congenital nuclear cataract and microphthalmia and showed an early loss of endoplasmic reticulum (ER) in the cortex and attenuation of nuclei degradation. This observation was confirmed by TEM analysis, as was the presence of autophagic vesicles in ßA3ΔG91 lenses. Comparative IHC and RT-qPCR analyses showed relatively higher levels of autophagy markers (ubiquitinated proteins and p62, LC3, and LAMP2 proteins) in ßA3ΔG91 lenses compared to WT lenses. Additionally, ßA3ΔG91 lenses showed relatively greater numbers of apoptotic cells and higher levels of cleaved caspase-3 and caspase-9. Conclusions: The deletion of G91 in ßA3ΔG91 mice leads to higher levels of expression of autophagy-related proteins and their transcripts relative to WT lenses. Taken together, G91 deletion in ßA3/A1-crystallin is associated with autophagy disruption, attenuation of nuclei degradation, and cellular apoptosis in the lens, which might be congenital cataract causative factors.


Asunto(s)
Catarata , Cristalino , Ratones , Animales , Catarata/genética , Catarata/metabolismo , Cristalino/metabolismo , Western Blotting , Modelos Animales de Enfermedad , Autofagia/genética
4.
BMC Ophthalmol ; 24(1): 163, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38609888

RESUMEN

BACKGROUND: The aim was to validate the correlation between corneal shape parameters and axial length growth (ALG) during orthokeratology using Image-Pro Plus (IPP) 6.0 software. METHODS: This retrospective study used medical records of myopic children aged 8-13 years (n = 104) undergoing orthokeratology. Their corneal topography and axial length were measured at baseline and subsequent follow-ups after lens wear. Corneal shape parameters, including the treatment zone (TZ) area, TZ diameter, TZ fractal dimension, TZ radius ratio, eccentric distance, pupil area, and pupillary peripheral steepened zone(PSZ) area, were measured using IPP software. The impact of corneal shape parameters at 3 months post-orthokeratology visit on 1.5-year ALG was evaluated using multivariate linear regression analysis. RESULTS: ALG exhibited significant associations with age, TZ area, TZ diameter, TZ fractal dimension, and eccentric distance on univariate linear regression analysis. Multivariate regression analysis identified age, TZ area, and eccentric distance as significantly correlated with ALG (all P < 0.01), with eccentric distance showing the strongest correlation (ß = -0.370). The regressive equation was y = 1.870 - 0.235a + 0.276b - 0.370c, where y represents ALG, a represents age, b represents TZ area, and c represents eccentric distance; R2 = 0.27). No significant relationships were observed between the TZ radius ratio, pupillary PSZ area, and ALG. CONCLUSIONS: IPP software proves effective in capturing precise corneal shape parameters after orthokeratology. Eccentric distance, rather than age or the TZ area, significantly influences ALG retardation.


Asunto(s)
Cristalino , Niño , Humanos , Estudios Retrospectivos , Topografía de la Córnea , Análisis Multivariante , Programas Informáticos
5.
Fam Med Community Health ; 12(Suppl 3)2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38609092

RESUMEN

Storylines of Family Medicine is a 12-part series of thematically linked mini-essays with accompanying illustrations that explore the many dimensions of family medicine, as interpreted by individual family physicians and medical educators in the USA and elsewhere around the world. In 'IV: perspectives on practice-lenses of appreciation', authors address the following themes: 'Relational connections in the doctor-patient partnership', 'Feminism and family medicine', 'Positive family medicine', 'Mindful practice', 'The new, old ethics of family medicine', 'Public health, prevention and populations', 'Information mastery in family medicine' and 'Clinical courage.' May readers nurture their curiosity through these essays.


Asunto(s)
Coraje , Fabaceae , Cristalino , Lentes , Unionidae , Humanos , Animales , Medicina Familiar y Comunitaria , Médicos de Familia
6.
J Refract Surg ; 40(4): e199-e207, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38593258

RESUMEN

PURPOSE: To investigate the efficacy of incorporating Generative Adversarial Network (GAN) and synthetic images in enhancing the performance of a convolutional neural network (CNN) for automated estimation of Implantable Collamer Lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT). METHODS: This study was a retrospective evaluation using synthetic data and real patient images in a deep learning framework. Synthetic ICL AS-OCT scans were generated using GANs and a secondary image editing algorithm, creating approximately 100,000 synthetic images. These were used alongside real patient scans to train a CNN for estimating ICL vault distance. The model's performance was evaluated using statistical metrics such as mean absolute percentage error (MAPE), mean absolute error (MAE), root mean squared error (RMSE), and coefficient of determination (R2) for the estimation of ICL vault distance. RESULTS: The study analyzed 4,557 AS-OCT B-scans from 138 eyes of 103 patients for training. An independent, retrospectively collected dataset of 2,454 AS-OCT images from 88 eyes of 56 patients, used prospectively for evaluation, served as the test set. When trained solely on real images, the CNN achieved a MAPE of 15.31%, MAE of 44.68 µm, and RMSE of 63.3 µm. However, with the inclusion of GAN-generated and algorithmically edited synthetic images, the performance significantly improved, achieving a MAPE of 8.09%, MAE of 24.83 µm, and RMSE of 32.26 µm. The R2 value was +0.98, indicating a strong positive correlation between actual and predicted ICL vault distances (P < .01). No statistically significant difference was observed between measured and predicted vault values (P = .58). CONCLUSIONS: The integration of GAN-generated and edited synthetic images substantially enhanced ICL vault estimation, demonstrating the efficacy of GANs and synthetic data in enhancing OCT image analysis accuracy. This model not only shows potential for assisting postoperative ICL evaluations, but also for improving OCT automation when data paucity is an issue. [J Refract Surg. 2024;40(4):e199-e207.].


Asunto(s)
Cristalino , Miopía , Lentes Intraoculares Fáquicas , Humanos , Tomografía de Coherencia Óptica/métodos , Implantación de Lentes Intraoculares/métodos , Estudios Retrospectivos , Miopía/cirugía
7.
PLoS One ; 19(4): e0300476, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38635668

RESUMEN

PURPOSE: To determine the effect of sex as a risk factor regarding presbyopia. METHODS: Maximum accommodation was pharmacologically induced (40% cabachol corneal iontophoresis) in 97 rhesus monkeys (49 males and 48 females) ranging in age from 8 to 36 years old. Accommodation was measured by Hartinger coincidence refractometry. RESULTS: Accommodative amplitude measured refractometrically decreased with age, and the rate of change was not different between males and females (p = 0.827). CONCLUSIONS: Presbyopia is essentially sex neutral, and no one is spared. There may be modest variations between different populations for various reasons, but essentially it is monotonously predictable. At present there is no biological therapeutic.


Asunto(s)
Cristalino , Presbiopía , Masculino , Animales , Femenino , Macaca mulatta , Acomodación Ocular , Envejecimiento
8.
Int Ophthalmol ; 44(1): 194, 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38656707

RESUMEN

PURPOSE: To evaluate the magnitude of IOL transversal shift (ITS) after phacoemulsification and to analyse the factors contributing to IOL decentration and ITS. METHODS: 94 consecutive patients who underwent cataract surgery and IOL implantation was enrolled. Each patient underwent anterior segment optical coherence tomography with CASIA 2 (Tomey, Nagoya, Japan) to assess crystalline lens decentration, thickness and diameter seven days preoperatively and at one and sixty days postoperatively. Univariate and multivariate linear regression analysis were performed to evaluate the determinants of ITS and final decentration. RESULTS: The preoperative crystalline lens diameter was associated with the ITS and with the IOL final decentration. A positive association between the final IOL decentration and the first post-surgical day decentration was found (p < 0.0001). CONCLUSION: Greater crystalline lens diameter was associated with greater decentration and with greater ITS. Day-one IOL decentration seems to be the main determinant of final IOL decentration.


Asunto(s)
Segmento Anterior del Ojo , Facoemulsificación , Tomografía de Coherencia Óptica , Humanos , Facoemulsificación/efectos adversos , Tomografía de Coherencia Óptica/métodos , Masculino , Femenino , Anciano , Segmento Anterior del Ojo/diagnóstico por imagen , Lentes Intraoculares/efectos adversos , Persona de Mediana Edad , Agudeza Visual , Anciano de 80 o más Años , Migracion de Implante de Lente Artificial/diagnóstico , Migracion de Implante de Lente Artificial/etiología , Implantación de Lentes Intraoculares/efectos adversos , Complicaciones Posoperatorias/diagnóstico , Cristalino/diagnóstico por imagen , Estudios Prospectivos
9.
Int Ophthalmol ; 44(1): 198, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38662107

RESUMEN

PURPOSE: Cataract surgery in microphthalmic eyes is challenging due to anatomical restraints, hard bulky nucleus. This series aims to evaluate the safety and efficacy of couching of intraocular lens in irido-fundal coloboma with microphthalmos. SETTING: Tertiary care centre in South India. DESIGN: Retrospective non-comparative study in eyes with irido-fundal coloboma, corneal diameter < 7 mm and brown cataract. Visual acuity less than 6/60 in other eye. METHODS: Anterior chamber entry made, zonules broken and lens dislocated into the vitreous cavity in a controlled manner. Baseline Clinico-demographic details, corrected distance visual acuity (CDVA), Intra-ocular pressure (IOP), corneal diameter, axial length, lens status and post-surgery CDVA, IOP and complications recorded and followed up for atleast 6 months. RESULTS: Fifteen eyes of 15 subjects were evaluated with a mean age 49.4 ± 10.9 years. At baseline, mean IOP 14.5 ± 3.8 mmHg, mean axial length 19.3 ± 0.5 mm, mean corneal diameter was 6.5 ± 0.34 mm and CDVA 2 logMAR which improved to 1.5 logMAR at 3 months (p value 0.002). Transient spike in IOP in 33.3% subjects was medically managed with no significant difference in IOP (p > 0.05) at baseline (14.5 ± 3.8 mmHg), 3 months post-surgery (16 ± 2.8 mmHg) and 6 months post-surgery (14.9 ± 2.5 mmHg). One patient underwent re-couching. No other major complications were noted. CONCLUSION: Couching of cataractous lens is an effective and safe method in microphthalmic eyes with irido-fundal coloboma as last resort procedure, where no other surgical procedure may work. It provides an ambulatory gain of visual acuity in previously non-ambulatory subjects. Corneal measurements help in determining the subset of patients where couching offers viable option.


Asunto(s)
Catarata , Coloboma , Microftalmía , Agudeza Visual , Humanos , Estudios Retrospectivos , Femenino , Coloboma/diagnóstico , Coloboma/complicaciones , Coloboma/cirugía , Masculino , Microftalmía/complicaciones , Microftalmía/diagnóstico , Microftalmía/cirugía , Catarata/complicaciones , Catarata/congénito , Catarata/diagnóstico , Persona de Mediana Edad , Adulto , Iris/cirugía , Iris/anomalías , Implantación de Lentes Intraoculares/métodos , Extracción de Catarata/métodos , Cristalino/anomalías , Cristalino/cirugía , Estudios de Seguimiento
10.
Health Phys ; 126(5): 339-345, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38526252

RESUMEN

ABSTRACT: After considering epidemiological studies on the induction of cataracts in individuals exposed to radiation, the International Commission on Radiological Protection recommended, in 2012, a reduction in the annual eye-dose limit of occupationally exposed workers. This imposed higher performance demands on existing dosimetry systems and the development of new dosimetry technologies. The operational quantity to be measured is Hp(3), the personal dose equivalent at a depth of 3 mm in an ICRU 4-element tissue cylinder 20 cm in height and 20 cm in diameter. The conversion coefficients per unit incident fluence, Hp(3)/Φ, were calculated using Monte Carlo simulation codes. In the case of incident electrons, the literature shows that the resulting coefficients depend on the electron transport options selected for the Monte Carlo simulations as well as the tally zone thickness. In this study, electron operational eye-lens dose coefficients were calculated using MCNP6.2 in its default settings and by invoking the single-event feature. The results were compared to those from PENELOPE, a well-known code for its enhanced accuracy in handling low-energy electron transport. The results are in agreement for the entire energy range for these two series of simulations, but differences are found with previously published dose coefficients in the literature. This impacts the calibration of dosimeters for electrons and may require a change in the commonly accepted dose coefficients.


Asunto(s)
Catarata , Cristalino , Humanos , Electrones , Método de Montecarlo , Calibración
11.
Int Ophthalmol ; 44(1): 142, 2024 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-38493427

RESUMEN

PURPOSE: The purpose of this study was to investigate the effect of circ_HLCS on age-related cataract (ARC). METHODS: Circ_HLCS, microRNA (miR)-338-3p, and bisphosphate 3'-nucleotidase 1 (BPNT1) were quantified by quantitative real-time polymerase chain reaction or western blot. Cell proliferation and cell viability were assessed by the 5-Ethynyl-2'-deoxyuridinr and cell counting kit-8 assays. Cell apoptosis was detected by flow cytometry. Targeted correlations among circ_HLCS, miR-338-3p, and BPNT1 were verified by the dual-luciferase reporter and RNA pull-down assays. RESULTS: circ_HLCS was diminished in ARC tissues and UV-treated SRA01/04 cells. Elevated content of circ_HLCS undermined UV-induced cell proliferation inhibition and apoptosis. Mechanistically, circ_HLCS directly targeted miR-338-3p, and circ_HLCS regulated BPNT1 expression through miR-338-3p. Furthermore, reduction of miR-338-3p ameliorated UV-induced SRA01/04 cell damage by increasing BPNT1 expression. CONCLUSION: Taken together, these data suggested that circ_HLCS inhibited apoptosis of UV-treated SRA01/04 cells by miR-338-3p/BPNT1 axis. Therefore, circ_HLCS might be a potential therapeutic target for ARC.


Asunto(s)
Cristalino , MicroARNs , Humanos , ARN Circular/genética , Apoptosis , Proliferación Celular , Células Epiteliales , MicroARNs/genética
12.
BMJ Open Ophthalmol ; 9(1)2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38531624

RESUMEN

OBJECTIVE: To compare sustainability, financial implications and surgical efficiency of two phacoemulsification cassette systems for cataract surgery: a machine with single-use cassettes and another with daily, reusable ones. METHODS: Observational study involving retrospective cataract surgery data collection at the Centre Médical de l'Alliance, Braine-l'Alleud, Belgium, a tertiary eye care centre. Information on cassette weight, quantities and transport volume was obtained from routine procedures and purchasing records. The costs for each machine were calculated by reviewing the invoices received from the accounting department. RESULTS: We found significant differences across comparisons. The reusable cassette machine, when compared with the single-use machine, used 306.7 kg less plastic (75.3% reduction), required 2494 m3 less storage per 1000 surgeries (67.7% decrease) and cost €54.16 less per 10 procedures (16.9% reduction). The machine with daily reusable cassettes also exhibited a 7-minute priming time advantage for 10 procedures, reducing downtime between cases. CONCLUSIONS: Our findings underscore the benefits of adopting reusable cassette systems: reduced plastic consumption, storage volume and priming time, as well as enhanced efficiency and cost-savings. Healthcare professionals and institutions are encouraged to embrace environmentally conscious initiatives. The use of reusable cassette systems for cataract surgeries offers a pathway to sustainable practices.


Asunto(s)
Extracción de Catarata , Catarata , Cristalino , Facoemulsificación , Humanos , Estudios Retrospectivos
14.
J Radiol Prot ; 44(2)2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38507786

RESUMEN

Vision badge is an eye lens dosimeter to measureHp(3). This study aimed to evaluate the basic characteristics of the Vision badge and its performance as an eye lens dosimeter for endoscopists by phantom study. Energy dependence was evaluated by changing the tube voltage to 50 kV (effective energy of 27.9 keV), 80 kV (32.2 keV), and 120 kV (38.7 keV). Dose linearity was evaluated by changing the number of irradiation to 1, 5, and 40 times, which corresponded to 0.53, 5.32, and 21.4 mGy. Batch uniformity was evaluated by calculating the coefficient of variation ofHp(3) obtained from 10 Vision badges. Angular dependence was evaluated at 0° (perpendicular to the incident direction of x-rays), 30°, 60°, 75°, and 90°. The Vision badge and optically stimulated luminescence (OSL) dosimeter were attached to the inside of the radioprotective glasses, worn on the endoscopist phantom, and theHp(3) obtained from both dosimeters were compared. TheHp(3) obtained from the Vision badge with 38.7 keV was 3.8% higher than that with 27.9 keV. The Vision badge showed excellent linearity (R2= 1.00) with the air kerma up to 21.4 mGy. The coefficient of variation of theHp(3) for 10 Vision badges was 3.47%. The relative dose of the Vision badge decreased as the angle increased up to 75°, but increased at 90°. TheHp(3) obtained by the OSL dosimeter and the Vision badge were decreased as the endoscopist phantom was turned away from the patient phantom. TheHp(3) that was obtained by the Vision badge was 35.5%-55.0% less than that obtained by the nanoDot. In conclusion, the Vision badge showed specific angular dependence due to its shape, but satisfactory basic properties were exhibited for all characteristics. In phantom study, the Vision badge showed generally similar trends with the OSL dosimeter.


Asunto(s)
Cristalino , Dosímetros de Radiación , Humanos , Radiografía , Rayos X , Fantasmas de Imagen , Cristalino/efectos de la radiación
15.
J Agric Food Chem ; 72(13): 7203-7218, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38518258

RESUMEN

Diabetes complications are associated with aldose reductase (AR) and advanced glycation end products (AGEs). Using bioassay-guided isolation by column chromatography, 10 flavonoids and one coumarin were isolated from Poncirus trifoliata Rafin and tested in vitro for an inhibitory effect against human recombinant AR (HRAR) and rat lens AR (RLAR). Prunin, narirutin, and naringin inhibited RLAR (IC50 0.48-2.84 µM) and HRAR (IC50 0.68-4.88 µM). Docking simulations predicted negative binding energies and interactions with the RLAR and HRAR binding pocket residues. Prunin (0.1 and 12.5 µM) prevented the formation of fluorescent AGEs and nonfluorescent Nε-(carboxymethyl) lysine (CML), as well as the fructose-glucose-mediated protein glycation and oxidation of human serum albumin (HSA). Prunin suppressed the formation of the ß-cross-amyloid structure of HSA. These results indicate that prunin inhibits oxidation-dependent protein damage, AGE formation, and AR, which may help prevent diabetes complications.


Asunto(s)
Complicaciones de la Diabetes , Cristalino , Florizina/análogos & derivados , Poncirus , Ratas , Humanos , Animales , Glucosa/farmacología , Poncirus/metabolismo , Reacción de Maillard , Productos Finales de Glicación Avanzada/metabolismo , Albúmina Sérica Humana , Aldehído Reductasa/metabolismo , Fructosa
16.
Ophthalmic Physiol Opt ; 44(3): 593-604, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38436461

RESUMEN

This study considered two questions associated with intraocular lens (IOL) power and refraction: (1) Given a refraction with a particular IOL in the eye, what will be the refraction for the IOL or another IOL if located differently with regard to tilt or anterior-posterior position? (2) For a target refraction, what is the power of another IOL if located differently with regard to tilt or position? A thin lens technique was developed to address these questions. For the first question, light was traced through the initial correcting spectacle lens to the cornea, refracted at the cornea, transferred to the position of the initial IOL, refracted at this IOL, transferred to the position of a new IOL (which may be the same IOL but with a different position and/or tilt), refracted backwards through the new IOL, transferred to the cornea and refracted out of the eye to give a new correcting spectacle lens power. For the second question, light was traced through the initial correcting spectacle lens to the cornea, refracted at the cornea, transferred to the position of the initial IOL, refracted at the initial IOL and transferred to the position of a new IOL. Light was also traced through the second correcting spectacle lens, refracted at the cornea and transferred to the position of the second IOL. The difference between the reduced image vergence for the first raytrace and the reduced object vergence for the second raytrace gave the effective power of the second IOL, and from this, the power of the second IOL was determined. Examples are presented for different situations, including a case report.


Asunto(s)
Cristalino , Lentes Intraoculares , Errores de Refracción , Humanos , Errores de Refracción/diagnóstico , Errores de Refracción/terapia , Refracción Ocular , Córnea
19.
Exp Eye Res ; 241: 109858, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38467176

RESUMEN

The eye lens is responsible for focusing objects at various distances onto the retina and its refractive power is determined by its surface curvature as well as its internal gradient refractive index (GRIN). The lens continues to grow with age resulting in changes to the shape and to the GRIN profile. The present study aims to investigate how the ageing process may influence lens optical development. Murine lenses of accelerated senescence-prone strain (SAMP8) aged from 4 to 50 weeks; senescence-resistant strain (SAMR1) aged from 5 to 52 weeks as well as AKR strain (served as control) aged from 6 to 70 weeks were measured using the X-ray interferometer at the SPring-8 synchrotron Japan within three consecutive years from 2020 to 2022. Three dimensional distributions of the lens GRIN were reconstructed using the measured data and the lens shapes were determined using image segmentation in MatLab. Variations in the parameters describing the lens shape and the GRIN profile with age were compared amongst three mouse strains. With advancing age, both the lens anterior and posterior surface flattens and the lens sagittal thickness increase in all three mouse strains (Anterior radius of curvature increase at 0.008 mm/week, 0.007 mm/week and 0.002 mm/week while posterior radius of curvature increase at 0.002 mm/week, 0.007 mm/week and 0.003 mm/week respectively in AKR, SAMP8 and SAMR1 lenses). Compared with the AKR strain, the SAMP8 samples demonstrate a higher rate of increase in the posterior curvature radius (0.007 mm/week) and the thickness (0.015 mm/week), whilst the SAMR1 samples show slower increases in the anterior curvature radius (0.002 mm/week) and its thickness (0.013 mm/week). There are similar age-related trends in GRIN shape in the radial direction (in all three types of murine lenses nr2 and nr6 increase with age while nr4 decrease with age consistently) but not in the axial direction amongst three mouse strains (nz1 of AKR lens decrease while of SAMP8 and SAMR1 increase with age; nz2 of all three models increase with age; nz3 of AKR lens increase while of SAMP8 and SAMR1 decrease with age). The ageing process can influence the speed of lens shape change and affect the GRIN profile mainly in the axial direction, contributing to an accelerated decline rate of the optical power in the senescence-prone strain (3.5 D/week compared to 2.3 D/week in the AKR control model) but a retardatory decrease in the senescence-resistant strain (2.1 D/week compared to the 2.3D/week in the AKR control model).


Asunto(s)
Envejecimiento , Cristalino , Ratones , Animales , Japón
20.
PLoS One ; 19(3): e0296811, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38512912

RESUMEN

BACKGROUND: To analyze vault effects of crystalline lens rise (CLR) and anterior chamber parameters (recorded by Pentacam) in highly myopic patients receiving implantable collamer lenses (ICLs), which may avoid subsequent complications such as glaucoma and cataract caused by the abnormal vault. METHODS: We collected clinical data of 137 patients with highly myopic vision, who were all subsequent recipients of V4c ICLs between June 2020 and January 2021. Horizontal ciliary sulcus-to-sulcus diameter (hSTS) and CLR were measured by ultrasonic biomicroscopy (UBM), and a Pentacam anterior segment analyzer was used to measure horizontal white-to-white diameter (hWTW), anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), CLR, and postoperative vault (Year 1 and Month 1). The lens thickness (LT) was determined by optical biometry (IOL Master instrument). The predictive model was generated through multiple linear regression analyses of influential factors, such as hSTS, CLR, hWTW, ACD, ACA, ACV, ICL size, and LT. The predictive performance of the multivariate model on vault after ICL was assessed using the receiver operating characteristic (ROC) curve with area under the curve (AUC) as well as the point of tangency. RESULTS: Average CLR assessed by UBM was lower than the average value obtained by Pentacam (0.561 vs. 0.683). Bland-Altman analysis showed a good consistency in the two measurement methods and substantial correlation (r = 0.316; P = 0.000). The ROC curve of Model 1 (postoperative Year 1) displayed an AUC of 0.847 (95% confidence interval [CI]: 74.19-95.27), with optimal threshold of 0.581 (sensitivity, 0.857; specificity, 0.724). In addition, respective values for Model 2 (postoperative Month 1) were 0.783 (95% CI: 64.94-91.64) and 0.522 (sensitivity, 0.917; specificity, 0.605). CONCLUSION: CLR and anterior chamber parameters are important determinants of postoperative vault after ICL placement. The multivariate regression model we constructed may serve in large part as a predictive gauge, effectively avoid postoperative complication.


Asunto(s)
Cristalino , Miopía , Lentes Intraoculares Fáquicas , Humanos , Implantación de Lentes Intraoculares/efectos adversos , Agudeza Visual , Cristalino/cirugía , Cámara Anterior/diagnóstico por imagen , Miopía/cirugía , Estudios Retrospectivos
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