Aetiology, Diagnosis and Treatment of Arterial Occlusions of the Retina-A Narrative Review.

Arterial occlusions of the retina are potentially sight-threatening diseases which often result in profound visual loss. The aim of this narrative review is to provide an overview of the aetiology, discuss major risk factors, describe the management and systemic assessments and evaluate existing therapies. For this review, an extensive literature search in PubMed was performed. Emboli from the heart or the carotid arteries can cause ophthalmic artery occlusion (OAO), central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO). Most patients with arterial occlusions have vascular risk factors such as arterial hypertension, hyperhomocysteinaemia, carotid stenosis and atrial fibrillation, which also increase the risk of cerebral stroke and myocardial infarction. Therapies such as ocular massage, thrombolysis and anterior chamber paracentesis have been suggested but are still equivocal. However, it is evident that retinal artery occlusion should be immediately treated and accompanied by interdisciplinary collaboration, since early diagnosis and the proper treatment of possible risk factors are important to reduce the risk of further damage, recurrences, other vascular diseases and mortality.

Possible limits of calibrating reading charts with the Landolt ring: a microscopic study.

PURPOSE: To evaluate microscopically whether the print quality and accuracy of sizing of Landolt ring near vision charts are adequate for the calibration of reading charts. METHODS: Near vision charts with Landolt rings from Oculus GmbH (C-Test; Wetzlar, Germany), Precision Vision (Woodstock, IL) and the RADNER Charts were examined, as well as custom-made Landolt rings optimized for print quality. Microscopic investigations and measurements were performed by using a Huvitz HSZ 600 stereomicroscope (Nikon NIS Elements software) to evaluate the height of the Landolt rings, the thickness of the lines, and the width of the openings. The deviations from the mathematically correct values, which were calculated as given in the EN/ISO 8596 and by the International Council of Ophthalmology (ICO), were analyzed (calculated for a test distance of 40 cm). RESULTS: All the near vision charts showed notable deficiencies in print quality and aberrations from the nominal values in the height, thickness of the lines, and width of the openings. The openings were too narrow, whereas the height and thickness of the lines were larger than the nominal values. Even the openings of Landolt rings optimized for print quality were not always within an acceptable 5% tolerance and need further improvement. CONCLUSION: This study reports inaccuracies in the heights, thicknesses of the lines, and widths of the openings of Landolt rings in all the near vision charts investigated. The extent of these inaccuracies excludes such near vision charts as reference tests for the calibration of reading charts. The x-height in relation to the visual angle still seems to be the most reliable method for standardizing the print sizes for reading charts.

Towards a standardisation of reading charts: Font effects on reading performance-Times New Roman with serifs versus the sans serif font Helvetica.

PURPOSE: The purpose was to compare systematically the legibility of a font without serifs (Helvetica) and one with serifs (Times New Roman). METHODS: Three paragraphs that were equal in the number of words, syllables, characters, difficulty and reading length were printed at equal size, with equal spacing between the lines and equal layout (paperback style), in either the sans serif typeface Helvetica Neue T1 55 Roman (Adobe) or the serif typeface Times New Roman PS Roman (Adobe). They were also printed in newspaper format in the serif font. The paragraphs were presented in random order (Latin square design) to 36 participants between 18 and 38 years of age (wearing their best-corrected visual acuity). Reading duration was measured with a stopwatch. Reading time, reading speed and the number of reading errors were compared. RESULTS: For the paperback layout, no significant difference in reading time (p = 0.50) or reading speed (p = 0.56) was found between the two fonts. The correlation between the two fonts was high for both reading time and speed (r = 0.93). The mean number of reading errors was the same (0.31 ± 0.58 errors/text) for both fonts. There was a significant difference in reading time and speed between the paperback and the newspaper layout. CONCLUSION: The legibility of Helvetica and Times New Roman is similar when investigated under equivalent conditions. Thus, these two font types can be used as interchangeable standard typefaces.

Font effects on reading parameters: comparing Radner Reading Charts printed in Helvetica and Times Roman.

PURPOSE: To investigate the effect of font choice on reading parameters by using the RADNER Reading Charts printed in two fonts (Helvetica vs. Times Roman) equalized in terms of x-height. METHODS: This is a cross-sectional study of 40 participants with healthy eyes (18 to 60 years of age; mean: 42.13 ± 12.28 years). Reading performance was evaluated binocularly with RADNER Reading Charts printed in either Helvetica Neue (T1) Roman sans serif (Adobe) or Times New Roman PS Roman serif (Adobe). The test distance was 40 cm. Reading charts were presented in random order. Reading acuity (RA), mean reading speed of all sentences read (MEAN-ALL RS), mean reading speed from 0.8 logRAD to 0.3 logRAD (MEAN-RS), maximum reading speed (MAX-RS), and critical print size (CPS) were compared. RESULTS: The RA values obtained for the Helvetica and Times Roman fonts (in full logarithmic units of 0.1 logRAD) did not differ between the two fonts (mean for both fonts: - 0.128 ± 0.064 logRAD; 95% CI for both: - 0.148; - 0.107 logRAD). The differences in all other reading parameters between the two fonts were small and not statistically significant. The analyses revealed narrow confidence intervals and good coefficients of reliability. Except for the CPS (r = 0.49) and RA (equal for Helvetica and Times Roman), the correlations for all parameters were high, ranging from r = 0.92 to r = 0.98. CONCLUSION: The equivalent reading performance obtained with Helvetica and Times Roman (when equalized in x-height and layout) makes these font types interchangeable as standards for reading charts.

Long-term results of MyoRing treatment of keratoconus / Resultados a largo plazo del tratamiento del queratocono con MyoRing

Purpose: To study long-term results of MyoRing treatment of keratoconus. Methods: Retrospective study of MyoRing implantation into a corneal pocket for keratoconus. Results: Corneal thickness at the thinnest point remained unchanged, SIM K's, manifest sphere and cylinder were significantly improved at the first follow-up 9 months postoperatively and remained stable until the last follow-up about 5 years after surgery. Uncorrected and corrected distance visual acuity (UDVA, CDVA) were significantly improved at the first follow-up 9 months postoperatively and were further ameliorated until the last follow-up about 5 years after surgery. Conclusion: The treatment was safe and effective with continuing improvement of visual acuity during the 5 years after surgery (AU)

Objetivo: Estudiar los resultados a largo plazo del tratamiento del queratocono con MyoRing. Método: Estudio retrospectivo de la implantación del MyoRing en un bolsillo corneal en los casos de queratocono. Resultados: El espesor de la córnea en el punto más fino no reflejó cambios, mejorando los valores de SIM K, esfera y cilindro manifiesto durante el seguimiento a los 9 meses de la intervención y permaneciendo entonces estables hasta el último seguimiento a los 5 años de la misma. La agudeza visual no corregida y corregida (UDVA, CDVA) mejoró considerablemente a los 9 meses de la intervención, y continuaron mejorando significativamente hasta el último seguimiento a los 5 años de la misma. Conclusión: El tratamiento resultó seguro y efectivo, con mejora continua de la agudeza visual durante los 5 años posteriores a la cirugía (AU)

Long-term results of MyoRing treatment of keratoconus.

PURPOSE: To study long-term results of MyoRing treatment of keratoconus. METHODS: Retrospective study of MyoRing implantation into a corneal pocket for keratoconus. RESULTS: Corneal thickness at the thinnest point remained unchanged, SIM K's, manifest sphere and cylinder were significantly improved at the first follow-up 9 months postoperatively and remained stable until the last follow-up about 5 years after surgery. Uncorrected and corrected distance visual acuity (UDVA, CDVA) were significantly improved at the first follow-up 9 months postoperatively and were further ameliorated until the last follow-up about 5 years after surgery. CONCLUSION: The treatment was safe and effective with continuing improvement of visual acuity during the 5 years after surgery.

Visualization of the oculomotor cranial nerves by magnetic resonance imaging.

MRI is the imaging method of choice in patients with cranial nerve palsies. However, the nerves are often not seen on MR images and smaller lesions may not be diagnosed on routine brain MRI. The purpose of this study is to show that the oculomotor cranial nerves can be visualized by standard MR sequences and to present an update on clinical applications of cranial nerve imaging. In MR images of normal subjects, it is demonstrated that the oculomotor nerve, the trochlear nerve and the abducens nerve can be identified not only in the subarachnoid space and cavernous sinus, but also in the orbit. However, a precondition is the use of appropriate imaging sequences and planes (e.g., subarachnoid cisterns: T2-weighted fast spin-echo or T2*-weighted three-dimensional sequences in oblique-axial and sagittal planes; cavernous sinus: contrast-enhanced T1-weighted coronal images; orbit: T1-weighted images without contrast agent in the coronal plane obtained using surface coils). The capability of imaging cranial nerves is clinically important not only for diagnostic purposes in eye muscle palsies but also for planning surgical procedures at the cranio-orbital junction.

Magnetic resonance imaging of the orbit: Basic principles and anatomy.

This review article gives a basic introduction to the technical principles of magnetic resonance imaging for ophthalmologists and orbital surgeons and describes the anatomical structures that can be identified on high-resolution magnetic resonance images of the orbit. The meaning of general imaging parameters, specific weighting of the images, and the use of contrast agents, fat suppression techniques and surface coils is explained. Possible artifacts are also described. The advantages and disadvantages of MRI in comparison with computed tomography (CT) are discussed in order to give recommendations for the use of the appropriate imaging modality in patients with orbital disorders. Apart from delineating the course of the extraocular muscles, high-resolution MRI is able to depict not only all important blood vessels and cranial nerves of the orbit but also major septa of the orbital connective tissue system. Clinical applications are also mentioned to show that high-resolution MRI may contribute to a specific diagnosis in orbital disease.