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No Useful Field Expansion with Full-field Prisms
摘要： Full-field prisms that fill the entire spectacle eye wire have been considered as field expansion devices for homonymous hemianopia (HH) and acquired monocular vision (AMV). Although the full-field prism is used for addressing binocular dysfunction and for prism adaptation training after brain injury as treatment for spatial hemineglect, we show that the full-field prism for field expansion does not effectively expand the visual field in either HH or AMV.
关键词： visual field,field expansion,full-field prisms,homonymous hemianopia,acquired monocular vision
更新于2025-09-10 09:29:36
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Field Expansion for Acquired Monocular Vision Using a Multiplexing Prism
摘要： SIGNIFICANCE: Acquired monocular vision (AMV) is a common visual field loss. Patients report mobility difficulties in walking due to collisions with objects or other pedestrians on the blind side. PURPOSE: The visual field of people with AMV extends more than 90° temporally on the side of the seeing eye but is restricted to approximately 55° nasally. We developed a novel field expansion device using a multiplexing prism (MxP) that superimposes the see-through and shifted views for true field expansion without apical scotoma. We present various designs of the device that enable customized fitting and improved cosmetics. METHODS: A partial MxP segment is attached (base-in) near the nose bridge. To avoid total internal reflection due to the high angle of incidence at nasal field end (55°), we fit the MxP with serrations facing the eye and tilt the prism base toward the nose. We calculated the width of the MxP (the apex location) needed to prevent apical scotoma and monocular diplopia. We also consider the effect of spectacle prescriptions on these settings. The results are verified perimetrically. RESULTS: We documented the effectivity of various prototype glasses designs with perimetric measurements. With the prototypes, all patients with AMV had field-of-view expansions up to 90° nasally without any loss of seeing field. CONCLUSIONS: The novel and properly mounted MxP in glasses has the potential for meaningful field-of-view expansion up to the size of normal binocular vision in cosmetically acceptable form.
关键词： prism glasses,visual field loss,field expansion,multiplexing prism,Acquired monocular vision
更新于2025-09-10 09:29:36
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Effects of Cataract Extraction on the Outcomes of Automated Perimetry and Retinal Nerve Fiber Layer Thickness Measurements by Optical Coherence Tomography in Primary Angle Closure Glaucoma
摘要： Objective: To evaluate the effect of cataract extraction on both visual field and retinal nerve fiber layer thickness measurements in primary angle closure glaucoma (PACG) eyes. Methods: Retrospective cohort study on 30 PACG eyes underwent cataract extraction. Changes in RNFL thickness and visual field parameters including mean deviation (MD), visual field index (VFI) and pattern standard deviation (PSD) were analyzed within 6 months before and after cataract extraction. Results: Overall, MD (p=0.003) and VFI (p=0.004) improved significantly after cataract extraction, whereas PSD showed no significant change (p=0.6). In the 10 eyes with MD worse than -20 dB, mean MD improved by 3.4 ± 3.56 dB (from -24.36 ± 3.06 dB to -20.96 ± 5.06 dB, p=0.01) and mean VFI improved by 16.25 ± 15.66% (from 23.38 ± 9.65% to 39.63 ± 20.83%, p=0.02). PSD showed no significant change after cataract extraction (p=0.07). In the 20 eyes with MD better than -20 dB, MD and VFI also improved postoperatively, but the changes did not reach statistical significance: mean MD improved by 1.64 ± 3.65 dB (from -11.57 ± 5.57 dB to -9.92 ± 5.36 dB, p=0.05) whilst mean VFI improved by 4.57 ± 12.29% (from 74.95 ± 17.95% to 79.52 ± 17.26%, p=0.07). RNFL thickness did not show any significant changes after cataract extraction (p=0.13). Conclusions: Both MD and VFI improved after cataract extraction, especially in eyes with pre-operative MD worse than -20 dB. PSD and RNFL thickness showed no significant change after cataract extraction.
关键词： Perimetry,Visual field,Extraction,Retinal nerve fiber layer thickness,Optical coherence tomography,Primary angle closure glaucoma,Cataract
更新于2025-09-10 09:29:36
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Asymptomatic Unexplained Visual Field Loss Diagnosed as Early Retinitis Pigmentosa without Pigmentation: A Case Report
摘要： Purpose: We report a case of asymptomatic unexplained visual field loss diagnosed as early retinitis pigmentosa (RP) without pigmentation. Case summary: A 33-year-old woman was referred to us with a constricted visual field (C24-2) before laser-assisted in-situ keratomileusis surgery. The visual field test (C30-2) revealed significantly decreased sensitivity between 15 to 25 degrees in both eyes. Close fundus examination revealed a subtle greyish retinal atrophic lesion along the vascular arcade and fluorescein angiography revealed a window defect in accordance with a retinal atrophic lesion in both eyes. Optical coherence tomography showed decreased retinal thickness around the macula. Electroretinogram revealed decreased b waves in rod response. Based on these findings, we diagnosed the patient with early RP without pigmentation. Conclusions: The possibility of early RP without pigmentation presenting as slight atrophy around the macula without significant pigmental degeneration should also be considered if a patient presents with peripheral visual field constriction without other symptoms. The ophthalmologist should ensure that the location of the visual field defect matches the location of the lesion. In addition, a detailed fundus examination with macular optical coherence tomography can be helpful to diagnose such a lesion.
关键词： Constricted central visual field,Electroretinogram,Macular optical coherence tomography,Early retinitis pigmentosa (RP) without pigmentation
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Systems Engineering Symposium (ISSE) - Rome, Italy (2018.10.1-2018.10.3)] 2018 IEEE International Systems Engineering Symposium (ISSE) - Implementation of support tools for the presumptive diagnosis of Glaucoma through identification and processing of medical images of the human eye
摘要： In medicine, the diagnosis of diseases by means of image processing has had great acceptability and credibility, which is why it has been able to explore in depth the theme, taking advantage of mainly which is a non-invasive method within the clinical study. Glaucoma is considered as a group of diseases that damages the optic nerve to the point of causing blindness in the eye, with the disadvantage of in most cases do not exhibit early symptoms. Through this work, the processing biomedical images to locate the parameters considered most relevant within images obtained from the back of the eye to make the determination of the existence or not of Glaucoma, a disease that mainly affects physically the dimensions and proportions of the cup and the optical disc. It gets the value of the reason cup/disc and is additional to the characteristics of the rule ISNT, both parameters considered of great importance in the diagnosis of glaucoma. The results obtained serve as a tool to support the specialist in ophthalmology and optometry in conjunction with a presumptive diagnosis of glaucoma, this way it looks for the early detection and prevention of this disease.
关键词： ISNT,visual field,cup-disc,Glaucoma,nerve fibers,image processing,optic nerve
更新于2025-09-09 09:28:46
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Loss of horizontal macular ganglion cell complex asymmetry: an optical coherence tomography indicator of chiasmal compression
摘要： Objective To estimate the macular ganglion cell complex (GCC) asymmetry in patients with suprasellar tumours, to compare its diagnostic performance to the nasal GCC thickness and visual field (VF) and to investigate how the parameters correlate with magnetic resonance imaging (MRI) findings. Methods and analysis Cross-sectional study of patients with suprasellar tumours affecting the optic chiasm. Macular optical coherence tomography (OCT) scans were evaluated for nasal GCC sector thinning and loss of normal GCC asymmetry between corresponding nasal-temporal sectors. Equivalently, VFs were analysed for defects compatible with chiasm dysfunction. The relationship between optic chiasm and tumour was measured on MRI. results Thirty-three eyes of 33 patients were included. There were OCT findings in 14 eyes. Nasal GCC thinning was found in 9 eyes and loss of GCC asymmetry in 12 eyes; the two parameters were not significantly different with respect to number of positive findings (p=0.45). Loss of GCC asymmetry, however, occurred in 5 eyes among 24 without GCC thinning (proportion 0.21; 95% confidence interval 0.071 to 0.42). In 8 eyes, VF indicated pathology; of these, 7 had concurring OCT findings. The prevalence of OCT and VF findings increased significantly with suprasellar tumour extension on MRI. Conclusion The diagnostic capabilities of nasal GCC thinning and loss of GCC asymmetry were comparable, whilst their complementary performances increased the proportion of eyes in which OCT suggested compression. The prevalence of both OCT and VF findings grew with suprasellar tumour extension. In several cases, however, structural findings on OCT preceded detectable VF deficits.
关键词： suprasellar tumours,visual field,optical coherence tomography,chiasmal compression,macular ganglion cell complex
更新于2025-09-09 09:28:46
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Correlation between optic nerve head structural parameters and glaucomatous visual field indices
摘要： We examined associations between optic nerve head structural parameters and glaucomatous visual field indices. The study population included patients with glaucomatous optic neuropathy who were evaluated at Aichi Medical University, Nagakute, Aichi, Japan, from October 2010 to January 2011. A total of 57 eyes from 33 patients were assessed. We measured visual field using a Humphrey field analyzer, peripapillary retinal nerve fiber layer thickness (RNFL-T), and Bruch’s membrane opening-minimum rim width (BMO-MRW) using spectral domain optical coherence tomography, and rim area with referring three-dimensional photography. Spearman’s rank correlation coefficients were calculated between the threshold of visual sensitivity or total deviation of visual field and the following five optic nerve head structural parameters: RNFL-T length, BMO-MRW length, rim area, and calculated RNFL-T and BMO-MRW volumes (each length multiplied by rim area). The Akaike information criterion was calculated to determine which structural parameter was the best predictor of each visual field index. Threshold of visual sensitivity had correlation coefficients of 0.23 with global sector of RNFL-T, 0.32 with BMO-MRW, 0.14 with rim area, 0.21 with RNFL-T volume, and 0.26 with BMO-MRW volume. The correlation coefficients for each parameter with total deviation of visual field were 0.22, 0.33, 0.28, 0.36, and 0.37, respectively. The Akaike information criterion of BMO-MRW showed the smallest values in analyses of both threshold of visual sensitivity and total deviation. The present results show that RNFL-T volume and BMO-MRW volume were more strongly correlated with total deviation than BMO-MRW, but BMO-MRW appeared to be the best predictor of the two glaucomatous visual field indices.
关键词： retinal nerve fiber layer thickness,rim area,visual field,glaucoma,spectral domain optical coherence tomography,Bruch’s membrane opening-minimum rim width
更新于2025-09-04 15:30:14
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Development of Visual Field Screening Procedures: A Case Study of the Octopus Perimeter
摘要： Purpose: We develop a methodology for designing perimetric screening procedures, using Octopus perimeters as a case study. Methods: The process has three stages: analytically determining specificity and number of presentations required for different multisampling suprathreshold schemes at a single location of the visual field, ranking visual field locations by their positive predictive value (PPV) for glaucoma, and determining a pass/fail criteria for the test. For the case study the Octopus G-program visual field test pattern is used, and a dataset of 385 glaucoma and 86 normal patients. Results: Using a 1-of-3 sampling strategy at a level equal to the 95 percentile of normal observers gave the most robust specificity under the influences of false-negative responses using an average of 1.5 presentations per location. The PPV analysis gave 19 locations that completely classified our glaucomatous data. A further 9 points were added to screen for nonglaucomatous loss. The final stage found that insisting that 3 locations are missed for the screening to fail gave a simulated specificity and sensitivity of approximately 95% for unreliable responders. Conclusions: Our method gives a principled approach to choosing between the many parameters of a visual field screening procedure. We have developed a procedure for the Octopus that should terminate in less than 1 minute for normal observers with high specificity and sensitivity to glaucoma. Translational Relevance: Visual field screening is used in community settings and eye care practice. This study provides a principled approach to the development of such screening procedures and details a new procedure.
关键词： screening,glaucoma,visual field
更新于2025-09-04 15:30:14