- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Contact Lenses || Cosmetic and Prosthetic Contact Lenses
摘要： In this chapter, coloured contact lenses are differentiated into cosmetic lenses, i.e. tinted contact lenses that simply change the colour of the eyes, and prosthetic lenses, i.e. lenses that change the appearance of an unsightly eye, although the term 'cosmetic lenses' is often used for the latter purpose. The fact that contact lenses can provide benefits other than visual is often overlooked, and their ability to change a patient's appearance should not be trivialised. A practitioner who wishes to provide prosthetic lenses for patients with disfigured eyes should have previous wide experience in fitting prescription lenses and tinted cosmetic lenses. The basic principles are the same, and lenses need to be tailored to each patient.
关键词： prosthetic lenses,contact lenses,cosmetic lenses,eye disfigurement,tinting methods
更新于2025-09-23 15:23:52
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Contact Lenses || Optics and Lens Design
摘要： Some aspects of contact lens design and optics are rarely applied nowadays, as they are less relevant to modern practice, but readers may still need to refer to them. They are available at: https://expertconsult.inkling.com/, whereas the more relevant topics are included here. The appendix, available at: https://expertconsult.inkling.com/, also describes various equations that are used in contact lens work, while the online resources include programs relating to both the optics and to lens design. There are two main aspects to be considered when dealing with the optics of contact lenses: the effects on the wearer of the optical differences from spectacles and the necessity for the practitioner to understand the components which affect the back vertex power (BVP) of the contact-lens/liquid*-lens system. There is some overlap of these two aspects, but for the sake of convenience they are discussed separately in the first two sections of the chapter. In the second section a set of approximate rules is included, the use of which should permit practitioners to make quick and reasonably accurate estimates of changes in power caused by altering certain lens parameters. The Cartesian sign convention2 is used throughout. For further understanding of the basic principles involved, readers are referred to the works of Bennett (1985), Tunnacliffe (1993), Freeman and Hull (2003), Douthwaite (2006) and Rabbetts (2007).
关键词： Lens Design,Astigmatism,Optics,Bifocal Contact Lenses,Power Variations,Contact Lenses,Ocular Refraction,Aberrations,Spectacles
更新于2025-09-23 15:23:52
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Relationship of Water Content With Silicon and Fluorine Contents of Silicone-Hydrogel Contact Lens Materials
摘要： Objectives: The relationship between water (W) content and silicon (Si) content of silicone-hydrogel (SiHy) contact lens materials was inspected using identical methodologies, equipment, and operators for materials composing 16 types of commercially available SiHy contact lenses. Fluorine (F) content was included in the analysis for the three materials also containing a fluoropolymer. One type of lens consisted of a bulk SiHy material coated with thin layers of conventional hydrogel. Methods: SiHy materials were obtained in the form of 16 contact lens brands purchased on the open market in a common range of refractive powers from -3 to +6 D in single lots. All test lenses were equilibrated at room temperature in a standard saline recommended in the American National Standards Institute Z80.20-2016 and International Organization for Standardization (ISO) 18369-4:2017 standards. W content was obtained gravimetrically, in %, according to those standards for 16 lenses of each SiHy material. Si content was determined in % using inductively coupled plasma optical emission spectroscopy for four digested lenses of each material. F content was determined in % using an ion-selective electrode for four combusted lenses of each of the three fluorinated SiHy materials. W and Si contents of the bulk SiHy material of the coated lens were estimated by computational exclusion of the hydrogel layers. Results: The linear coefficients of determination (R2, n=16) were 0.7576 (relating mean dry Si content [n=4] to mean W content [n=16]) and 0.8819 (relating mean hydrated Si content [n=4] to mean W content [n=16]). When the 4 SiHy materials that were fluorinated or coated were excluded from the analysis, the R2 values (n=12) were 0.8869 and 0.9263, respectively. When F contents and the coating were added to the assessments, the linear coefficients of determination (R2, n=16) became 0.8948 (relating mean dry [Si+F] content to mean W content) and 0.9397 (relating mean hydrated [Si+F] content to mean W content). Conclusions: There is a fundamental negative linear relationship between Si and W contents for SiHy contact lens materials above 35% W content that is followed when F content and hydrogel coatings are empirically added to the analysis below 35% W content. The relationship was tightest for hydrated (Si+F) content and W content, for which the regression equation had an R2 of 0.9397: (Si+F)= -0.3073 (W)+22.148. The relationship between (Si+F) and W therefore seems to be based on composition rather than structure of available SiHy contact lens materials.
关键词： Water content,Contact lenses,Silicone,Silicon,Hydrogel,Fluorine
更新于2025-09-23 15:23:52
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Use of therapeutic non-refractive contact lenses to improve visual outcome after repair of traumatic corneal wounds
摘要： Background: The purpose of this study was to evaluate the effect of use of contact lenses to improve visual outcome after repair of traumatic corneal wounds. Methods: Two groups of patients (n=30 each) with traumatic full thickness corneal wounds were entered into this study. All cases were caused by sharp objects such as a knife or piece of glass that produced a corneal full thickness wound without any other associated ocular injuries. One group was repaired and received medical treatment (non-contact lens group) and the other group was repaired and a soft contact lens was fitted over the cornea, then medically treated (contact lens group). Each patient was followed up until complete healing, the sutures were removed after about 6 weeks, and the patients were followed up for a further 6 weeks, for a complete follow-up period of 3 months, after which postoperative refraction, manifest refractive spherical equivalent, uncorrected visual acuity, and best-corrected visual acuity were measured and compared between the two groups. Results: After repair and follow-up, uncorrected visual acuity ≥0.3 (decimal system) was achieved in 19 cases (63%) in the contact lens group and in only 14 cases (47%) in the non-contact lens group (P=0.018). Best-corrected visual acuity ≥0.6 was achieved in 26 cases (87%) in the contact lens group and in only 17 cases (57%) in the control group (P=0.012). Conclusion: Soft contact lenses can be used after repair of traumatic corneal wounds to improve visual outcome.
关键词： non-refractive contact lenses,traumatic corneal wounds,visual outcome,repair
更新于2025-09-23 15:22:29
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Laser-inscribed contact lens sensors for the detection of analytes in the tear fluid
摘要： Tears exhibit compositional variations as a response to ocular and systemic metabolic conditions, and they can therefore be used for the assessment of physiological health. Here, microfluidic contact lenses were developed as wearable platforms for in situ tear pH, glucose, protein, and nitrite ions sensing. The microfluidic system was inscribed in commercial contact lenses by CO2 laser ablation. The microchannel consisted on a central ring with four branches, and biosensors were embedded within microcavities located at the branches ends. The device was tested with artificial tears and colorimetric readouts were performed using a smartphone-MATLAB algorithm based on the nearest neighbor model. Sensors responded within a time range of 15 seconds, and yielded sensitivities of 12.23 nm/pH unit, 1.4 nm/mmolL-1 of glucose, 0.49 nm/gL-1 of proteins, and 0.03nm/μmolL-1 of nitrites. Contact lens sensing platforms may provide on-eye tears screening with applications in the monitoring of the ocular health both in clinics and at point-of-care settings.
关键词： biomarkers,biosensors,tear fluid,Contact Lenses,point-of-care diagnostics
更新于2025-09-23 15:21:01
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Artificial pupil versus contralateral balanced contact lens fit for presbyopia correction
摘要： Purpose: To assess and compare the effects of contact lens-based artificial pupil design and contralateral balanced multifocal contact lens combination (CBMCLC) on visual performance. Methods: This randomized crossover study conducted at the University of Valencia, Spain included 38 presbyopic patients using an artificial pupil contact lens in the nondominant eye and a CBMCLC. After a month of lens wear, the binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance, and near contrast sensitivity and near stereoacuity (NSA) were measured under photopic conditions (85 cd/m2). Moreover, BDVA and binocular distance contrast sensitivity were examined under mesopic conditions (5 cd/m2). Results: Visual acuity at an intermediate distance and near vision was better with the CBMCLC than with the artificial pupil (p<0.05). Statistically significant differences were found in contrast sensitivity between the two types of correction for distance (under mesopic conditions) and for near vision, with the CBMCLC exhibiting better results in both cases (p<0.05). The mean NSA values obtained for the artificial pupil contact lens were significantly worse than those for the CBMCLC (p=0.001). Conclusion: The CBMCLC provided greater visual performance in terms of intermediate and near vision compared with the artificial pupil contact lens.
关键词： Prosthesis fitting,Pupil,Presbyopia/rehabilitation,Dominance, ocular,Contact lenses
更新于2025-09-23 15:21:01
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The effect of the optical design of multifocal contact lenses on choroidal thickness
摘要： Studies have found reduced myopia progression with multifocal contact lenses, albeit with an unclear mechanism behind their protective effect. It is hypothesized that the induced myopic defocus of the addition zones of the multifocal contact lenses leads to choroidal thickening and therefore inhibits eye growth. In the current study, the effect of the optical design of multifocal contact lenses on choroidal thickness was investigated. Eighteen myopic participants wore four different contact lenses ((1) single-vision lenses corrected for distance, (2) single-vision lenses with +2.50 D full-field defocus, (3) Multifocal center-distance design, (4) Multifocal center-near design, both with addition power +2.50 D) for 30 min each on their right eye. Automated analysis of the macular choroidal thickness and vitreous chamber depth were performed before and after the wear of each of the contact lenses. Peripheral refraction profiles in primary gaze were obtained using eccentric photorefraction prior to contact lens wear. Choroidal thickness and vitreous chamber depth showed no significant differences to baseline with any of the contact lenses (all p > 0.05). Choroidal thickness increased by +2.1 ± 11.1 μm with the Multifocal center-distance design, by +2.0 ± 11.1 μm with the full-field defocus lens, followed by the Multifocal center-near design with +1.6 ± 11.3 μm and the single-vision contact lens correcting for distance with +0.9 ± 11.2 μm. Multifocal contact lenses have no significant influence on choroidal thickness after short-term wear. Therefore, changes in choroidal thickness might not be the main contributor to the protective effect of multifocal contact lenses in myopia control.
关键词： multifocal contact lenses,choroidal thickness,optical design,defocus,myopia control
更新于2025-09-10 09:29:36
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Biomaterials and Regenerative Medicine in Ophthalmology || An introduction to ophthalmic biomaterials and their role in tissue engineering and regenerative medicine
摘要： The ultimate goal of the research and development of materials (other than drugs) for applications in medicine, which we call biomaterials, has always been to emulate natural materials. Since the natural target for biomaterials, ie, our body’s tissues and organs, is exceedingly complex, it is not surprising that in many instances the laboratory-made materials cannot match in their performance the natural entities they are meant to augment or replace. This is obviously different from the development of materials for industrial applications, which usually perform better than their natural counterparts (if the latter exist), and also evolve relatively fast, unhindered by the biological constraints inherent to living systems. For too long, an acceptable end performance in the short term was the main requirement from a biomaterial, with little attention paid to changing its bulk and/or surface properties through the manipulation of composition and/or structure, in order to maximize the clinical outcome. Over the past six decades or so, however, the progress in bringing the properties and functionality of biomaterials close to those of their biological targets has been remarkable. While the previous statements are valid for the ophthalmic biomaterials too, their development has shown some particular features. The general developments in the field of biomaterials have customarily been gauged through the achievements in the branches of orthopaedic biomaterials and, to a lesser extent, biomaterials for cardiology or dentistry, while the progress of biomaterials for the eye has usually been ignored or seldom presented.
关键词： ophthalmic biomaterials,artificial cornea,poly(methyl methacrylate),contact lenses,hydrogels,cornea,regenerative medicine,tissue engineering
更新于2025-09-10 09:29:36
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The Eye as a Window to Health: Albeit Slow, Research is Progressing on Contact Lenses for Medical Diagnostics
摘要： The idea is a compelling one: a device that looks and feels like an ordinary contact lens but that can continuously monitor a variety of health indicators. For a diabetic, such a lens might update blood glucose levels and, using a built-in flashing LED indicator light, signal when a condition needs attention. Diabetic patients might be saved from the need for repeated finger prick tests and could be monitored for longer periods of time and for a greater variety of parameters at once.
关键词： contact lenses,health monitoring,glucose monitoring,diabetes,medical diagnostics
更新于2025-09-10 09:29:36
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Association between multifocal soft contact lens decentration and visual performance
摘要： Purpose: The aim of this study was to assess the association between decentration of several commercial multifocal soft contact lenses (MFCLs) and various objective and subjective visual performance variables in presbyopic and non-presbyopic participants. Materials and methods: All presbyopic (age >40 years, near add ≥+1.25 D) and non-presbyopic (age ≥18 years, no near add requirements, spherical equivalent ≤-0.50 D) participants were each fitted bilaterally with six and two MFCLs (test lens), respectively, and with one single vision lens (control lens). Lens decentration, ie, the x- and y-differences between the contact lens and pupil centers, was objectively determined. Third-order aberrations were measured and compared. Visual performance (high- and low-contrast acuities and several subjective variables) was analyzed for any associations (Pearson’s correlation, r) with MFCL decentration. Results: A total of 17 presbyopic (55.1±6.9 years) and eight non-presbyopic (31.0±3.3 years) participants completed the study. All lenses displayed a temporal–inferior decentration (x=-0.36±0.29 mm, y=-0.28±0.28 mm, mean ± SD). Compared to the control, a significant inferior decentration was found for the Proclear? MFCL Near lens in both groups (ypresbyopic =-0.26 mm, ynon-presbyopic =-0.70 mm) and for the Proclear? MFCL Distance lens in the non-presbyopic group (ynon-presbyopic =-0.69 mm). In both groups, lens-induced vertical coma (C(3, -1)) was, by at least tenfold, significantly more positive for the Proclear? MFCL Distance lens and significantly more negative for the Proclear? MFCL Near lens. In the presbyopic group, the correlation of total MFCL decentration with vision variables was weak (r<|0.191|). Conversely, a moderate but significant correlation with total MFCL decentration was found in the non-presbyopic group for most of the vision variables, indicating a decrease in vision as decentration increased. Conclusion: Certain MFCLs decentered more than others; the same lens designs also induced significant amounts of third-order aberrations. An association between MFCL decentration and seven out of nine vision variables was found in the non-presbyopic group, ie, the group where lenses were most decentered, which had larger pupils and lower levels of inherent third-order aberrations.
关键词： vision,higher-order aberrations,multifocal contact lenses,decentration
更新于2025-09-09 09:28:46