Bradford Scholars -how to deposit your paper
Overview
Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.
Background
Many studies in multiple sclerosis (MS) have investigated the retina. Little however is known about the effect of MS on the cornea, which is innervated by the trigeminal nerve. It is the site of neural-immune interaction with local dendritic cells reacting in response- to environmental stimuli.
Objective
This study aims to investigate the effect of MS on- corneal nerve fibres and dendritic cells in the subbasal nerve plexus using in vivo confocal microscopy (IVCM).
Methods
We measured the corneal nerve fibre and dendritic cell density in 26 MS patients and matched healthy controls using a Heidelberg Retina Tomograph with Cornea Module. Disease severity was assessed with the Multiple Sclerosis Functional Composite, Expanded Disability Status Scale, visual acuity and retinal optical coherence tomography.
Results
We observed significant reduction in total corneal nerve fibre density in MS patients compared to controls. Dendritic cell density was similar in both groups. Reduced total nerve fibre density was associated with worse clinical severity, but not with previous clinical trigeminal symptoms, retinal neuroaxonal damage, visual acuity, or disease duration.
Conclusion
Corneal nerve fibre density is a promising new imaging marker for the assessment of disease severity in MS and should be investigated further.
For thin soft contact lenses, the level of spherical aberration and the consequent power change is similar on-eye and off-eye. Soft contact lenses corrected for spherical aberration in air will be expected to be aberration-free on-eye and produce only negligibly small power changes. For soft contact lenses without aberration correction, for higher levels of ametropia and large pupils, the soft contact lens power should be determined with trial lenses with their power and p value similar to the prescribed lens. The benefit of soft contact lenses corrected for spherical aberration depends on the level of ocular spherical aberration.
Bradford Scholars -how to deposit your paper
Overview
Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.
PURPOSE: Aspheric intraocular lenses (IOLs) are designed to correct spherical aberration in Pseudophakie eyes. We predict the benefit from correcting spherical aberration based on simulations and aberrometry of Pseudophakie eyes implanted with spherical IOLs.
METHODS: Ray tracing was performed through a model eye with an equi-biconvex spherical IOL and with a spherical aberration-correcting aspheric IOL. The IOLs were increasingly tilted and/or displaced, and the resulting transverse aberrations of 169 rays were transformed into Zernike coefficients for different pupil sizes. The benefit from correcting spherical aberration at individual mesopic pupils was investigated by canceling C? in the sets of Zernike coefficients for 41 eyes implanted with a spherical IOL.
RESULTS: Both the model eye and the real eye data predict that age-related miosis reduces spherical aberration in the eye implanted with a spherical IOL to approximately 1/3 of the spherical aberration at a 6-mm pupil. A reduction of similar magnitude occurs when spherical aberration -induced non-pa raxia I defocus is corrected by a spectacle lens. For natural mesopic pupils, canceling the Zernike C? coefficient improved the objective image quality at a rate similar to changing defocus by 0.05 diopters. Average decentration and tilt levels diminish the lead of aspheric IOLs over spherical IOLs, depending on the direction of decentration.
CONCLUSIONS: The benefit from correcting spherical aberration in a Pseudophakie eye is limited for some or all of the following reasons: wearing glasses, age-related miosis, tilt and decentration of IOL, small contribution of spherical aberration to all aberrations, and intersubject variability. [J Refract Surg. 2005;21:S541-S546.]
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