SciCombinator

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

Journal: Contact lens & anterior eye : the journal of the British Contact Lens Association

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

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

28

PURPOSE: To evaluate the refractive and corneal topographical changes of overnight orthokeratology in myopia with two brands of contact lenses. METHODS: Fourty-four eyes of 22 myopic patients with manifest refraction spherical equivalent (MRSE) of -1.00 to -5.00 D (cylinder≤-1.0) were fitted with either DreamLens (Hanita Lenses Investments, Hanita, Israel) (group A) or Rinehart-Reeves (R&R; Danker Laboratories, Sarasota, FL) (group B) reverse-geometry lenses. Each subject eye was evaluated in regards to the uncorrected and corrected distance visual acuities, manifest refraction, slit lamp biomicroscopy, and corneal topography at each follow-up examination. RESULTS: The follow-up was 1 year. For groups A and B, the mean uncorrected distance visual acuity was -0.02±0.10 logMAR (20/20) and -0.08±0.12 logMAR (20/20) respectively at year-1 examination. The mean MRSE decreased from -2.70±0.9D to -0.50±0.08D in group A and -3.1±1.1 to -0.62±0.18D in group B at week-1; and remained stable thereafter in each group. For both groups, starting with week-1, the mean anterior best-fit sphere (ABFS) was statistically significantly flatter from baseline. A high correlation was found between the change in apical corneal power (ACP) and MRSE (r(1)=0.79, r(2)=0.71), and there was a good correlation between the change in ABFS and MRSE (r(1)=0.67, r(2)=0.64) in both groups. No significant ocular adverse events were observed during study. CONCLUSIONS: Both types of contact lenses safely and effectively decreased the myopic refractive error at 1 year follow-up. The refractive effect was mainly induced by the changes in the anterior corneal shape and the ACP.

Concepts: Visual acuity, Cornea, Myopia, Lens, Orthokeratology, Contact lens, Refractive error, Keratoconus

27

PURPOSE: To determine the type and distribution of ocular conditions cared for in a clinic dedicated to scleral devices and to report the clinical outcomes afforded by this approach. METHODS: Fifty-one charts of patients fitted unilaterally or bilaterally with a scleral device (Prosthetic Replacement of the Ocular Surface Ecosystem - PROSE) in a two year period were retrospectively reviewed. Patient demographics, ocular diagnoses, associated systemic conditions, best corrected visual acuity (BCVA) before and after fitting, Visual Function Questionnaire score (VFQ-25), and ocular surface disease index (OSDI) score were collected. RESULTS: All 51 patients were successfully wearing the PROSE device for a period of anywhere from weeks to years. The most common reasons for fitting were to relieve symptoms of moderate to severe dry eye syndrome (“DES”, n=25), management of refractive problems (“refractive”, n=23) with keratoconus being the most common (n=14), and to manage other anomalies (“other”, n=3). Best corrected visual acuity (logMAR) improved with the wearing of the PROSE device for both the DES (17 letters) and the refractive group (10 letters), but not the “other” group. No serious complications were recorded for any of the patients. CONCLUSIONS: The PROSE device is a useful option not only for the management of ocular surface disease and optical imperfections, but also for other ophthalmic conditions. Moderate to severe dry eye was the most common anomaly managed, followed by eyes with irregular corneal astigmatism. DES and refractive patients experienced improvement in visual acuity with wearing of the PROSE device.

Concepts: Eye, Visual acuity, Ophthalmology, Contact lens, Anomaly, Refractive error, Tears, Keratoconjunctivitis sicca

26

Scleral contact lenses (ScCL) have gained renewed interest during the last decade. Originally, they were primarily used for severely compromised eyes. Corneal ectasia and exposure conditions were the primary indications. However, the indication range of ScCL in contact lens practices seems to be expanding, and it now increasingly includes less severe and even non-compromised eyes, too. All lenses that partly or entirely rest on the sclera are included under the name ScCL in this paper; although the Scleral Lens Education Society recommends further classification. When a lens partly rests on the cornea (centrally or peripherally) and partly on the sclera, it is called a corneo-scleral lens. A lens that rests entirely on the sclera is classified as a scleral lens (up to 25mm in diameter maximum). When there is full bearing on the sclera, further distinctions of the scleral lens group include mini-scleral and large-scleral lenses. This manuscript presents a review of the current applications of different ScCL (all types), their fitting methods, and their clinical outcomes including potential adverse events. Adverse events with these lenses are rare, but the clinician needs to be aware of them to avoid further damage in eyes that often are already compromised. The use of scleral lenses for non-pathological eyes is discussed in this paper.

Concepts: Eye, Cornea, Lens, Orthokeratology, Contact lens, Contact lenses, Keratoconus, Scleral lens

25

A 76 year old male presents with a corneal perforation in a phthisical eye. Definitive treatment in the form of an evisceration was delayed by 38 days. During this period a bandage contact lens prevented extrusion of ocular contents through an enlarging corneal perforation. This case demonstrates that a bandage contact lens can be effective in the immediate management of large corneal perforations whilst awaiting urgent definitive treatment.

Concepts: Eye, Cornea, Lens, Orthokeratology, Contact lens, Keratitis, Corneal ulcer

25

The present study was conducted to determine corneal topographic characteristics of children with vernal keratoconjunctivitis (VKC) and compare the corneal topographic indices in VKC subjects with normal subjects MATERIAL AND METHOD: In the hospital based comparative study, 115 consecutive subjects with VKC and 102 age and sex matched normal subjects were selected for the videokeratography with NIDEK ophthalmic operating system. Keratoconus-like topography was determined based on the expert classifier system. Other assessments included visual acuity testing with LogMAR chart, slit lamp biomicroscopy, dilated fundus examination, measurement of central corneal thickness and intraocular pressure. Topographic indices were analyzed and compared using unpaired t-test among different groups. Sensitivity and specificity was estimated by the ROC curve.

Concepts: Sensitivity and specificity, Visual acuity, Ophthalmology, Binary classification

25

To quantify the end-of-day silicone-hydrogel daily disposable contact lens fit and its influence of on ocular comfort, physiology and lens wettability.

Concepts: Cornea, Myopia, Lens, Contact lens, Corrective lens, Intraocular lens

0

To evaluate whether LipidTOX could stain lipid deposits on contact lens (CL) surfaces and compare lipid deposition patterns on various CL surfaces using an imaging method.

Concepts: Cornea, Java, Myopia, Lens, Contact lens, Corrective lens, Intraocular lens

0

First, to examine how wearing high and low modulus lenses with two different base curves affected lens fit, and the corneal tissue and bulbar conjunctival vascular tissue (bulbar redness and blood velocity). Secondly, to quantify the associations between these baseline and outcome variables and the third purpose was to correlate these variables with end of day comfort.

Concepts: Hematology, Eye, Tissue