SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Lens

212

A 19-year-old man presented with a mass in his right eye that had been present since birth but had gradually increased in size. The mass caused vision defects, mild discomfort on blinking, and the intermittent sensation of the presence of a foreign body.

Concepts: Brain, Retina, Eye, Visual perception, Depth perception, Lens, Teratoma, Binocular vision

177

Biological materials are often based on simple constituents and grown by the principle of self-assembly under ambient conditions. In particular, biomineralization approaches exploit efficient pathways of inorganic material synthesis. There is still a large gap between the complexity of natural systems and the practical utilization of bioinspired formation mechanisms. Here we describe a simple self-assembly route leading to a CaCO(3) microlens array, somewhat reminiscent of the brittlestars' microlenses, with uniform size and focal length, by using a minimum number of components and equipment at ambient conditions. The formation mechanism of the amorphous CaCO(3) microlens arrays was elucidated by confocal Raman spectroscopic imaging to be a two-step growth process mediated by the organic surfactant. CaCO(3) microlens arrays are easy to fabricate, biocompatible and functional in amorphous or more stable crystalline forms. This shows that advanced optical materials can be generated by a simple mineral precipitation.

Concepts: Optics, Mineral, Solid, Calcium carbonate, Metaphysics, Lens, Glass, Microlens

169

To compare the performance of two novel multipurpose disinfecting solutions (MPDS) in preventing silicone hydrogel contact lens dehydration, provide higher scores of subjective comfort and stable optical quality during a month of lens wear in neophyte volunteers.

Concepts: Cornea, Myopia, Lens, Contact lens, Contact lenses, Corrective lens, Intraocular lens, Oxygen permeability

168

We present an overview of currently available toric intraocular lenses (IOLs) and multifocal toric IOLs. Relevant patient selection criteria, IOL calculation issues, and surgical techniques for IOL implantation are discussed. Clinical outcomes including uncorrected visual acuity, residual refractive astigmatism, and spectacle independency, which have been reported for both toric IOLs and multifocal toric IOLs, are reviewed. The incidence of misalignment, the most important complication of toric IOLs, is determined. Finally, future developments in the field of toric IOLs are discussed. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Concepts: Ophthalmology, Lens, Presbyopia, Contact lens, Refractive error, Intraocular lens, Cataract, Toric lens

168

Coleoid cephalopods have an elaborate camera eye whereas nautiloids have primitive pinhole eye without lens and cornea. The Nautilus pinhole eye provides a unique example to explore the module of lens formation and its evolutionary mechanism. Here, we conducted an RNA-seq study of developing eyes of Nautilus and pygmy squid. First, we found that evolutionary distances from the common ancestor to Nautilus or squid are almost the same. Although most upstream eye development controlling genes were expressed in both species, six3/6 that are required for lens formation in vertebrates was not expressed in Nautilus. Furthermore, many downstream target genes of six3/6 including crystallin genes and other lens protein related genes were not expressed in Nautilus. As six3/6 and its controlling pathways are widely conserved among molluscs other than Nautilus, the present data suggest that deregulation of the six3/6 pathway led to the pinhole eye evolution in Nautilus.

Concepts: Gene expression, Evolution, Eye, Lens, Mollusca, Crystallin, Cephalopod, Nautilus

168

PURPOSE: To investigate differences in ocular aberrations induced by centre-near multifocal soft contact lenses (SCL) relative to single vision SCLs and their effect on contrast sensitivity function (CSF). METHODS: Ocular aberrometry was measured in 18 cyclopleged subjects (19-24 years) while wearing Ciba Air Optix low (AOlow) and high (AOhigh) add, Bausch & Lomb PureVision low (PVlow) and high (PVhigh) add multifocals, and a Bausch & Lomb PureVision single vision (PVsv) control with the same -3.00D distance back vertex power. Zernike polynomials were scaled to 4, 5 and 6mm pupils. CSF was measured at equivalent distances of 6m, 1m and 40cm while fully corrected with spherical trial lenses at 6m. RESULTS: AOlow, AOhigh and PVhigh induced a negative shift in primary spherical aberration (Z12) from PVsv and all multifocal SCLs induced a positive shift in secondary spherical aberration (Z24) (all p<0.01), without significantly increasing coma. Area under the CSF (AUCSF) reduced at 40cm for all multifocals relative to PVsv (p<0.05), but was not significantly different at 6m or 1m. A moderate correlation (r=-0.80, p<0.005) was found between changes in Z12 and AUCSF at 40cm for AOhigh, with an increase in negative Z12 reducing multifocal-induced loss of CSF. CONCLUSIONS: Centre-near multifocal SCLs induced a negative shift in Z12 and a positive shift in Z24. Although CSF was unaffected at 6m and 1m it was reduced at 40cm, possibly because changes in Z12 and Z24 were not great enough to induce a significant shift in centre of focus and increase in depth of field.

Concepts: Optics, Redox, Lens, Contact lens, Keratitis, Bausch & Lomb

167

PURPOSE: To compare the visual outcomes of additional multifocal intraocular lenses (IOLs) for sulcus fixation with those of standard multifocal IOLs in the capsular bag. SETTING: Department of Ophthalmology, Rudolf-Virchow-Klinikum Glauchau, Glauchau, Germany. DESIGN: Prospective controlled clinical trial. METHODS: Eyes had phacoemulsification and implantation of a monofocal IOL in the capsular bag and an additional aberration-free diffractive IOL in the ciliary sulcus (multifocal add-on IOL group). Measurements of uncorrected and distance-corrected distance, intermediate, and near visual acuities; contrast sensitivity; and defocus curve were performed 3 months postoperatively. Results were compared with those in eyes with an aberration-correcting diffractive posterior chamber IOL (multifocal PC IOL group). RESULTS: The multifocal add-on IOL group comprised 34 eyes of 20 patients and the multifocal PC IOL group, 31 eyes of 17 patients. Cataract surgery, IOL implantation, and the postoperative course were uneventful in all cases. There were no statistically significant differences in uncorrected and distance-corrected distance, intermediate, or near visual acuities between the 2 groups. The median uncorrected distance visual acuity was 0.00 logMAR in both groups, and the median uncorrected near visual acuity was 0.10 logMAR in both groups. Contrast sensitivity testing yielded significantly better results in the multifocal add-on IOL group, especially at spatial frequencies over 1.5 cycles per degree. Defocus curves were similar in the 2 groups. CONCLUSION: Visual performance with a multifocal diffractive add-on IOL was equivalent to that achieved with a commonly used multifocal diffractive PC IOL. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Concepts: Statistical significance, Visual acuity, Ophthalmology, Lens, Contact lens, Intraocular lens, Eye surgery, Cataract

164

Recent advances in wearable electronics combined with wireless communications are essential to the realization of medical applications through health monitoring technologies. For example, a smart contact lens, which is capable of monitoring the physiological information of the eye and tear fluid, could provide real-time, noninvasive medical diagnostics. However, previous reports concerning the smart contact lens have indicated that opaque and brittle components have been used to enable the operation of the electronic device, and this could block the user’s vision and potentially damage the eye. In addition, the use of expensive and bulky equipment to measure signals from the contact lens sensors could interfere with the user’s external activities. Thus, we report an unconventional approach for the fabrication of a soft, smart contact lens in which glucose sensors, wireless power transfer circuits, and display pixels to visualize sensing signals in real time are fully integrated using transparent and stretchable nanostructures. The integration of this display into the smart lens eliminates the need for additional, bulky measurement equipment. This soft, smart contact lens can be transparent, providing a clear view by matching the refractive indices of its locally patterned areas. The resulting soft, smart contact lens provides real-time, wireless operation, and there are in vivo tests to monitor the glucose concentration in tears (suitable for determining the fasting glucose level in the tears of diabetic patients) and, simultaneously, to provide sensing results through the contact lens display.

Concepts: Eye, Cornea, Myopia, Lens, Contact lens, Corrective lens, Tears, Wireless energy transfer

156

Binocular diplopia is a debilitating visual symptom requiring immediate intervention for symptomatic control, whether or not definitive treatment is eventually possible. Where prismatic correction is infeasible, the current standard is occlusion, either by a patch or an opaque contact lens. In eliminating one problem-diplopia-occlusive techniques invariably create another: reduced peripheral vision. Crucially, this is often unnecessary, for the reduced spatial resolution in the periphery limits its contribution to the perception of diplopia. Here, we therefore introduce a novel soft contact lens device that instead creates a monocular central scotoma inversely mirroring the physiological variation in spatial acuity across the monocular visual field, thereby suppressing the diplopia with minimal impact on the periphery. We compared the device against standard eye patching in 12 normal subjects with prism-induced binocular diplopia and 12 patients with binocular diplopia of diverse causes. Indexed by self-reported scores and binocular perimetry, the scotogenic contact lens was comparably effective in eliminating the diplopia while significantly superior in acceptability and its impact on the peripheral visual field. This simple, inexpensive, non-invasive device may thus be an effective new tool in the treatment of a familiar but still troublesome clinical problem.

Concepts: Eye, Vision, Visual perception, Lens, Binocular vision, Visual field, Perimetry, Scotoma

150

Lentil (Lens culinaris) is one of the cool season grain legume crops and an important source of dietary proteins and fibre. Fungal diseases are main constraints to lentil production and account for significant yield and quality losses. Lentil has a narrow genetic base presumably due to a bottleneck during domestication and as a result, any resistance to fungal diseases in the cultivated genepool is gradually eroded and overcome by pathogens. New sources of resistance have been identified in wild lentil (Lens ervoides). This article provides an overview of harnessing resistance potential of wild germplasm to enhance genetic resistance in lentil cultivars using next-generation sequencing-based genotyping, comparative genomics and marker-assisted selection breeding.

Concepts: Gene, Genetics, Genomics, Pulse, Fabaceae, Lens, Dietary fiber, Lentil