259 research outputs found
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Smartphone ophthalmoscopy: patient and student practitioner perceptions
It can take several years to become proficient at direct ophthalmoscopy; the instrument’s single eyepiece allows only one individual to view the image at a time, which is considered disadvantageous during teaching. The introduction of smartphone ophthalmoscopes enables groups of teachers and students to view images together which could encourage peer-to-peer learning. In addition, the technology is significantly cheaper than the direct ophthalmoscope. User acceptability and engagement is essential to the success of any (medical) technological innovation. We sought to understand student opinions of a new commercially-available smartphone device for fundus examination, and compare usability to the traditional ophthalmoscope, from the perspective of both student practitioners and patients. Fifty-four undergraduate optometry students with prior experience of the traditional direct ophthalmoscope were asked to examine at least one eye with the D-EYE smartphone ophthalmoscope and also given an opportunity to experience the D-EYE from a patient’s perspective. Minimal instructions were provided and all examinations conducted through undilated pupils. Participants completed an opinion survey to feedback on aspects such as the ease of handling and working distance. Compared to the direct ophthalmoscope, 92% of students preferred the (longer) working distance of the D-EYE; 77% felt it was easier to handle; and 92% preferred the patient experience with the D-EYE. Despite the positive feedback, only 43% of students preferred the D-EYE when assuming the role of the practitioner. Free text responses indicated that students felt the D-EYE may be most useful as a teaching tool. Student opinions indicated that smartphone ophthalmoscopes are an effective training tool for students as an accompaniment to learning the traditional ophthalmoscope method
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Changes in forward light scatter parameters as a function of refractive error in young adults
Background/aims
Some aspects of visual performance worsen with increasing myopia. Whilst the underlying causes are not always clear, reduction in retinal image quality is often attributed to structural changes in the posterior myopic eye. Forward light scatter, originating principally from the cornea and lens, is known to produce veiling glare which subsequently reduces retinal image contrast. It is therefore of interest to investigate whether forward light scatter varies with refractive error.
Methods
Thirteen young-adult subjects (18–25 years), with mean spherical errors (MSE ± sd, D) RE, − 1.69 ± 2.02 (range 0.38 to − 4.75); LE, − 1.91 ± 1.94 (range 0.50 to − 4.63) underwent binocular assessment of forward light scatter using the AVOT light scatter test. Five glare annuli, with effective eccentricities ranging from 2 to 10°, were used to estimate parameters, k and n, which define the light scatter function of the eye. These were then used to calculate the area under the light scatter function (k′) and the total volume of light scatter (k″).
Results
Significant correlation was found between increasing myopia and k′ values (RE, p 0.05 for both eyes). Axial length was also not correlated with any of the light scatter parameters measured.
Conclusion
The preliminary data from this study provide evidence that some light scatter parameters may be correlated with refractive error. Further studies are needed to characterize how changes in the anterior media of the eye, and inclusion of a wider range of refractive errors, may affect forward light scatter
Causes of congenital corneal opacities and their management in a tertiary care center.
PURPOSE: To evaluate causes and management of congenital corneal opacities (CCO) diagnosed in a tertiary care eye center and to compare the data with a previous study at the same institution.
METHODS: Computerized medical records in all patients with congenital corneal opacities diagnosed in the Cornea Service at Wills Eye Hospital (Philadelphia, PA) between January 1, 2007, and December 31, 2015, were retrospectively reviewed. Children aged 12 years and younger at the first visit were included in the study. Patients\u27 demographics, ocular diagnosis, laterality, associated ocular abnormalities, other ocular surgery performed prior or subsequent to the first visit, and their treatment were extracted from the medical records.
RESULTS: A total of 77 eyes in 56 patients were examined. The mean age at presentation was 32.8 ± 44.2 months, with the mean follow-up period of 26.7 ± 30.1 months. The most frequent diagnosis was Peters anomaly (53.2%), followed by limbal dermoid (13.0%), aniridia with glaucoma and microphthalmos (6.5%), sclerocornea and congenital glaucoma (5.2%), idiopathic (3.9%), Axenfeld-Rieger anomaly and Hurler syndrome (2.6%), and microcornea (1.3%). Primary keratoplasty was performed in 26 eyes, with the outcome rate in the clear cornea of 76.0% during the follow-up.
CONCLUSION: Peters anomaly is the most common cause of congenital corneal opacities encountered at our institution. Penetrating keratoplasty is the most frequent choice of corneal surgery to treat congenital corneal opacities. Additional interventions during penetrating keratoplasty were moderately positively correlated with graft failure. This study also shows the rates of some etiologies of that changed over the recent decades in our tertiary care Cornea Service. Although Peters anomaly remains the most common presenting reason for congenital corneal opacities, its rate appears to be increasing over the recent decade. Congenital corneal opacities due to birth trauma, which is one of the preventable causes, were observed in a previous study in our clinic; however, no new cases were noted in this study
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Evaluating a new objective grading software for conjunctival hyperaemia
Background/ Aims: Standardised numeric grading scales are used in ophthalmic practice to improve consistency between clinicians in recording the severity of ocular conditions and to facilitate the monitoring of such changes. We investigated the intra- and inter-observer grading reliability and the agreement between subjective Cornea and Contact Lens Research Unit (CCLRU) and Efron grading scales as well as a new Advanced Ophthalmic Systems (AOS) software which uses an objective approach to grading conjunctival hyperaemia.
Methods: One experienced observer graded n = 30 bulbar and n = 26 palpebral conjunctival hyperaemia images to 0.1 increments. Masked grading of randomised images was undertaken for all three methods, on two separate occasions. The agreement within and between the grading methods was assessed between sessions, and compared to the results of a novice observer.
Results: There were no statistically significant differences (P > 0.05) between test and retest values. However, repeatability in the grading estimates of both bulbar and palpebral conjunctival hyperaemia was improved using the AOS grading method (R2 = 0.998; Coefficient of Repeatability CoR 0.10–0.13), compared to Efron (R2 = 0.926; CoR 0.62) and CCLRU (R2 = 0.885–0.911; CoR 0.50–0.78). Intraclass coefficient correlations (ICC) improved inter-observer agreement using objective (> 0.995) versus subjective methods (0.853–0.959).
Conclusion: These subjective and objective grading methods are not interchangeable. Due to the excellent repeatability and improved agreement between experienced and novice observers, the objective grading method provides a more consistent approach when grading ocular abnormalities and may achieve greater reliability in record keeping and clinical monitoring in the future
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Shape of the posterior vitreous chamber in human emmetropia and myopia
PURPOSE: To compare posterior vitreous chamber shape in myopia to that in emmetropia. METHODS: Both eyes of 55 adult subjects were studied, 27 with emmetropia (mean spherical error [MSE] ≥ -0.55; <+0.75 D; mean +0.09 ± 0.36 D) and 28 with myopia (MSE -5.87 ± 2.31 D). Cycloplegic refraction was measured with a Shin Nippon autorefractor and anterior chamber depth and axial length with a Zeiss IOLMaster. Posterior vitreous chamber shapes were determined from T2-weighted magnetic resonance imaging (3.0-T) using procedures previously reported by our laboratory. Three-dimensional surface model coordinates were assigned to nasal, temporal, superior, and inferior quadrants and plotted in two dimensions to illustrate the composite shape of respective quadrants posterior to the second nodal point. Spherical analogues of chamber shape were constructed to compare relative sphericity between refractive groups and quadrants. RESULTS: Differences in shape occurred in the region posterior to points of maximum globe width and were thus in general accord with an equatorial model of myopic expansion. Shape in emmetropia is categorized distinctly as that of an oblate ellipse and in myopia as an oblate ellipse of significantly less degree such that it approximates to a sphere. There was concordance between shape and retinotopic projection of respective quadrants into right, left, superior, and inferior visual fields. CONCLUSIONS: Prolate ellipse posterior chamber shapes were rarely found in myopia, and we propose that spherical shape in myopia may constitute a biomechanical limitation on further axial elongation. Synchronization of quadrant shapes with retinotopic projection suggests that binocular growth is coordinated by processes that operate beyond the optic chiasm
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Inter-eye asymmetry in corneal topography and classification of corneal astigmatism
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The Effects of Severe Myopia on the Properties of Sampling Units in Peripheral Retina
SIGNIFICANCE: Poor peripheral visual acuity in myopia may reflect, in part, photoreceptor misalignment with the exit pupil of the eye. We speculate that if such misalignment causes sufficient visual deprivation and/or disrupts retinal feedback processes, it may influence eye growth itself. PURPOSE: It is known that myopic eyes have a reduced peripheral resolution acuity relative to emmetropic eyes, though it remains unclear how mechanical stretching of the retina in myopia impacts on peripheral visual performance. Our aim was to determine how retinal stretching affects the properties of sampling units in peripheral vision. METHODS: Three-dimensional magnetic resonance imaging provided a depiction in vivo of ocular shape, allowing the inter-eye ratio of retinal image surface areas and the relative alignment of surfaces to be determined in our observer, who was unique in having severe myopia in the right eye (~21 D) but only modest myopia in the left (~3 D). Visual performance was assessed for the detection and direction discrimination of drifting sinusoids positioned 40° in the temporal retina. Applying the sampling theorem to our measures, we estimated the density and cut-off frequency of the underlying sampling units. RESULTS: The retinal image surface area of the right eye was 40% larger than that of the left and was rotated 8.9° anticlockwise relative to the left eye's image surface. In agreement with a linear stretch model of myopia, the sampling density of the right eye was reduced by approximately the same ratio as that predicted from the inter-eye MRI data, namely, 1.18. However, the cut-off frequency (cycles/mm) of the right eye was approximately half that of the left, a reduction that cannot be explained solely by a linear areal expansion of retinal sampling units. CONCLUSIONS: Poor peripheral acuity in severe myopia may be caused, at least in part, by receptoral misalignment with the exit pupil
Anterior Chamber Characteristics, Endothelial Parameters, and Corneal Densitometry After Descemet Stripping Automated Endothelial Keratoplasty in Patients With Fuchs Dystrophy
Purpose: To compare anterior segment parameters in patients with Fuchs endothelial dystrophy (FED) who underwent Descemet stripping automated endothelial keratoplasty (DSAEK) in one eye and no corneal surgery in the fellow eye.
Methods: This prospective study was conducted on 28 eyes of 14 patients with FED who underwent DSAEK in one eye at least one year prior (DSAEK group) and no corneal surgery in the fellow eye (control group). Each eye was analyzed with the anterior segment optical coherence tomography, specular microscopy, and Scheimpflug imaging systems. Data were compared between the two groups.
Results: The mean age of the patients was 76.9 ± 7.0 years. There were no statistically significant differences in the mean central corneal thickness (CCT), central anterior chamber depth, anterior chamber angle parameters, cylinder and keratometry values between two groups (all P-values > 0.05). The paracentral corneal thickness, corneal volume, endothelial cell density, and hexagonal cell ratio measurements were statistically significantly higher in the DSAEK group than the control (all P-values < 0.05), and anterior chamber volume in the DSAEK group was significantly less than the control (P = 0.046). While posterior and total corneal densitometry values in the DSAEK group were statistically significantly lower than the control (P < 0.001 and P = 0.011, respectively), there were no statistically significant differences in the anterior or middle corneal densities (P = 0.108 and P = 0.134, respectively).
Conclusion: We found that total corneal densitometry value decreased in DSAEK group. Although DSAEK surgery did not affect the anterior chamber angle parameters, it reduced the anterior chamber volume and increased the corneal volume and paracentral corneal thickness due to the addition of the DSAEK graft
4-[(Z)-(2-Ethoxy-4-oxochroman-3-ylidene)methylamino]benzenesulfonamide monohydrate
In the molecule of the title compound, C18H18N2O5S·H2O, the heterocyclic ring adopts a twisted conformation, while the aromatic rings are oriented at a dihedral angle of 45.46 (3)°. Intramolecular C—H⋯O and N—H⋯O interactions result in the formations of planar five- and six-membered rings. In the crystal structure, N—H⋯O hydrogen bonds link the NH2 and SO2 groups through R
2
2(8) ring motifs, while C—H⋯O and N—H⋯O hydrogen bonds result in the formation of R
2
1(7) ring motifs. N—H⋯O and O—H⋯O hydrogen bonds link the uncoordinated water molecules, forming a polymeric network. A weak C—H⋯π interaction is also present
Implementing excellence in diversity, equity, and inclusion in the library workforce: Tips to overcome challenges
Diversifying the library workforce is challenging, with the graduation data of library and information science degrees not representing equity in demographics for diverse populations. Is this the reason for the lack of diversity among library staff or are recruitment practices not based on measurable performance standards? Both questions call upon the library and information science (LIS) profession to address diverse staffing issues to remedy these challenges
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