Extent Of Visual Field Loss Research Articles

Effects of socioeconomic status on baseline values and outcomes at 24 months in the Treatment of Advanced Glaucoma Study randomised controlled Trial

Background/aimsSocioeconomic status (SES) is associated with late disease presentation and poorer outcomes. We evaluate the effect of SES on treatment outcomes and report the correlation between SES and baseline characteristics...

Sellar masses: diagnosis and treatment.

Sellar mases can cause a variety of neuro-ophthalmic manifestations, including compressive optic neuropathy, chiasmal syndrome, and ophthalmoplegia due to cranial nerve palsy. Diagnosis involves a thorough history, neuro-ophthalmic examination, and ancillary tests and investigations. Visual field testing is critical in diagnosing and localizing the lesion and determining the extent of visual field loss. Appropriate neuro-imaging is essential in characterizing and localizing the lesion. Neuro-ophthalmologic assessment include meticulous clinical examination and ancillary tests including,visual field testing, which is useful in localizing the lesion, and optical coherence tomography, which is helpful in assessing the degree of axonal and neuronal loss and predicting the visual outcome. Treatment requires a multidisciplinary approach by different specialties, including radiologists, neuro-ophthalmologists, and neurosurgeons. The two primary treatment modalities for these tumors are surgery and radiation therapy. We review the main types of sellar lesions, their neuro-ophthalmologic evaluation, and treatment options.

Correlation between Intraocular Pressure and Visual Field Loss in Primary Open Angle and Primary Angle Closure Glaucoma: A Cross-Sectional Study

Introduction: Glaucoma is characterised by structural damage to optic nerve head with corresponding visual field defects and often associated with increased Intraocular Pressure (IOP). It may be broadly classified as Primary Angle Closure Glaucoma (PACG) and Primary Open Angle Glaucoma (POAG). It is one of the leading causes of global blindness, and a major proportion occurs in Indian population. Aim: To study the correlation between pretreatment IOP and extent of visual field loss in PACG and POAG. Materials and Methods: A cross-sectional observational study was carried out in Regional Institute of Ophthalmology, Trivandrum, Kerala, India from April 2016 to May 2017. Newly diagnosed cases of PACG (25 patients-13 males, 12 females, mean age 58.72±10.07 years) and POAG (85 patients- 45 males, 40 females, mean age 60.28±10.42 years) underwent a detailed glaucoma evaluation which included IOP measurement with Goldmann applanation tonometer and visual field testing using Humphrey Field Analysis (HFA) 24-2 pattern. Mean Deviation (MD), Pattern Standard Deviation (PSD) and Advanced Glaucoma Intervention Score (AGIS) score was calculated from reliable visual field test result. All data were coded and entered in to statistical software, Statistical Package for Social Sciences (SPSS) version 16.0 for analysis. The correlation between pretreatment IOP and visual field loss in patients with PACG and POAG was determined by Pearson Correlation of Coefficient. Results: Amongst the total 110 patients of this study, 25 patients were of PACG while POAG were in 85 patients. A significant correlation between pre treatment IOP and the extent of visual field loss in PACG was noted. There was no significant correlation in POAG. Linear regression analysis demonstrated a significant positive correlation between IOP and AGIS score in PACG (Pearson correlation coefficient(r)=0.805, p<0.001), not in POAG (r=0.026, p=0.816). Correlation between IOP and MD is statistically significant in PACG (r=0.812, p<0.001) but not in POAG (r=0.058, p=0.597). The correlation between IOP and PSD is not statistically significant in both groups (p-value >0.450). Conclusion: A significant correlation between IOP and visual field loss in PACG indicates that extent of visual field damage can be controlled by controlling IOP alone in PACG. The correlation between the pretreatment IOP and visual field loss in POAG is not statistically significant which agrees with the current proposed pathophysiology of optic neuropathy in which multiple factors influence in addition to IOP.

The Effect of Simulated Visual Field Loss on Optokinetic Nystagmus.

PurposeAssessment of functional vision across the visual field is hampered by a reliance on patients' subjective judgement of the presence of a stimulus, and the accompanying demands (time and attention) this places on them. As a first step toward determining whether an objective measure of an involuntary eye movement (optokinetic nystagmus [OKN]) could provide an objective measure of field loss, we determined how various measures of OKN depend on the extent of simulated visual field loss (SVFL).MethodsWe used infrared eye-tracking to measure the eye movements of 16 healthy participants viewing horizontally translating 2-dimensional noise patterns over trials of varying contrasts and different levels of SVFL. We quantified the strength of OKN by estimating the velocity of tracking eye movements compared to the stimulus (OKN gain). These measurements were made using an open-loop SVFL paradigm, where a varying amount of gaze-contingent peripheral stimuli was occluded.ResultsFull-field stimulation led to an average OKN gain of 0.92 ± 0.15. This value fell steadily with increasing SVFL to a value of 0.38 ± 0.20 when the periphery was not stimulated at all (i.e., the stimulus was a 5-deg. diameter foveal patch). We note considerable individual variation in OKN gain in all conditions.ConclusionsMeasuring the extent of visual field loss using an objective measure of OKN gain is feasible.Translational RelevanceSimulated visual field loss reduces optokinetic nystagmus, but further refinement of this technique would be required to overcome individual differences and to pick up clinically relevant field defects.

Using sellar region tumor's size as a predictor of psychophysical and electrophysiological perimetric visual losses: a logistic regression approach.

Sellar region tumor growth represents an important cause of visual loss due to mechanical compression of the optic nerve apparatus. Many investigations have used non-invasive tools to evaluate the visual field consequences of this damage, and good associations have been reported between psychophysical and electrophysiological perimetries. Few reports have considered the tumor size as a predictor of visual field loss. In the present study, we evaluated the association between the visual perimetry measured by Humphrey visual field analyzer and multifocal visual evoked cortical potential (mfVECP) and the tumor size. Our sample was composed of 14 patients diagnosed with sellar tumors by magnetic resonance imaging. We accounted the number of sectors with negative visual responses for both methods. A simple logistic regression analysis was used to evaluate the association between the tumor dimensions and the visual field features RESULTS: Three patients had preserved visual fields, three patients showed hemianopic defects, and eight patients had generalized visual field losses at both evaluations. We observed that the three maximum diameters of the tumor and total tumor volume had different predictive abilities regarding the extent of visual field loss when using psychophysical and mfVECP data. The maximum craniocaudal diameter of the tumor was the better predictor of the psychophysical measurements, whereas for the mfVECP results, all tumor dimensions and volumes had similar values that predict visual field losses. Tumor size as a predictor of visual loss has potential to assist in the clinical intervention and to prevent the irreversible visual impairment caused by tumors of the sellar region.

Changes in the Anterior Lamina Cribrosa Morphology with Glaucoma Severity

This study was designed to evaluate if primary open angle glaucoma (POAG) and its severity are associated with the shape of the lamina cribrosa (LC) as measured by a global shape index (LC-GSI), or other indices of LC curvature or depth. Optical coherence tomography (OCT) scans of the optic nerve head (OHN) were obtained from subjects with POAG (n = 99) and non-glaucomatous controls (n = 76). ONH structures were delineated, the anterior LC morphology reconstructed in 3D, and the LC-GSI calculated (more negative values denote greater posterior concavity). Anterior LC depth and 2D-curvature were also measured. Severity of glaucoma was defined by the extent of visual field loss, based on the Hodapp-Parrish-Anderson grading. Linear regression analyses compared LC characteristics between controls, mild-moderate, and advanced POAG groups. After adjusting for age, gender, ethnicity, intraocular pressure, axial length and corneal curvature, the LC-GSI was most negative in the advanced POAG group (mean [standard error] = −0.34 [0.05]), followed by the mild-moderate POAG group (−0.31 [0.02]) and then controls (−0.23 [0.02], PTrend = 0.01). There was also a significant trend of increasing LC depth and greater LC horizontal curvature with increasing severity of glaucoma (PTrend = 0.04 and 0.02, respectively). Therefore, with more severe glaucoma, the LC-GSI was increasingly more negative, and the anterior LC depth and curvature greater. These observations collectively correspond to greater cupping of the ONH at the level of the LC. As the LC-GSI describes the 3D anterior LC morphology, its potential usage may be complementary to existing ONH parameters measured on OCT.

Quantitative analysis of visual field loss after 577 nm krypton pan-retinal photocoagulation for diabetic retinopathy

Objective To observe the visual field loss after 577 nm krypton pan-retinal photocoagulation (PRP) in the treatment of diabetic retinopathy (DR). Methods A prospective clinical studies. Forty-six eyes of 26 patients with proliferative DR (PDR) and severe non-proliferative DR (NPDR) diagnosed by clinical examination from No. 306 Hospital of PLA during January 2014 and December 2015 were included in this study. Among them, 21 eyes of NPDR and 20 eyes of PDR; 13 eyes with diabetic macular edema (DME) (DME group) and 28 eyes without DME (non-DME group). All eyes underwent best corrected visual acuity (BCVA), fundus color photography, fundus fluorescein angiography (FFA) and optical coherence tomography (SD-OCT) examinations. The visual field index (VFI) and visual field mean defect (MD) values were recorded by Humphrey-7401 automatic visual field examination (center 30° visual field). The BCVA of DR eyes was 0.81±0.28; the VFI and MD values were (89.8±8.4)% and −7.5±3.85 dB, respectively. The BCVA of the eyes in the without DME group and DME group were 0.92±0.20 and 0.57±0.27, the VFI were (90.86±7.86)% and(87.46±9.41)%, the MD values were −6.86±3.43 and 8.87±4.48 dB. PRP was performed on eyes using 577 nm krypton laser. The changes of VFI, MD and BCVA were observed at 1, 3, and 6 months after treatment. Results Compared with before treatment, the VFI of DR eyes decreased by 12.0%, 12.3% and 14.8% (t=7.423, 4.549, 4.79; P 0.05) and MD value (t=−0.560, −0.337; P>0.05) at different time points after treatment. Compared with before treatment, the BCVA was significantly decreased in DR eyes at 1 month after treatment, the difference was statistically significant (t=2.871, P 0.05) and MD values (t=1.582, 0.776, 0.927, 1.098; P>0.05) between the two groups. Conclusion The range of 30° visual field loss is about 12%-14.8% after 577 nm krypton laser PRP for DR. VFI and MD can quantitatively analyze the and extent of visual field loss after PRP treatment. Key words: Diabetic retinopathy/therapy; Laser coagulation/adverse effects; Visual fields

Structure-function correlations in Retinitis Pigmentosa patients with partially preserved vision: a voxel-based morphometry study

Retinitis Pigmentosa is a group of hereditary retinal dystrophy disorders associated with progressive peripheral visual field loss. The impact of this retinal loss in cortical gray matter volume has not been addressed before in Retinitis Pigmentosa patients with low vision. Voxel-based morphometry was applied to study whole brain gray matter volume changes in 27 Retinitis Pigmentosa patients with partially preserved vision and 38 age- and gender-matched normally sighted controls to determine whether peripheral visual loss can lead to changes in gray matter volume. We found significant reductions in gray matter volume that were restricted to the occipital cortex of patients. The anteromedial pattern of reduced gray matter volume in visual primary and association cortices was significantly correlated with the extent of the peripheral visual field deficit in this cohort. Moreover, this pattern was found to be associated with the extent of visual field loss. In summary, we found specific visual cortical gray matter loss in Retinitis Pigmentosa patients associated with their visual function profile. The spatial pattern of gray matter loss is consistent with disuse-driven neuronal atrophy which may have clinical implications for disease management, including prosthetic restoration strategies.

Preference pattern of low vision aids in glaucoma-redefining guidelines

Context: Low vision is an important aspect of glaucoma care which required custom based prescription of low vision devices (LVDs) to suit the needs of the patient. Purpose: To evaluate preference pattern of LVDs in glaucoma patients. Setting and Design: Retrospective hospital-based review in a low vision service of a tertiary eye care center. Materials and Methods: Criteria for low vision was defined as best corrected distance visual acuity < 20/80 in the better eye with logarithm of the minimum angle of resolution chart and/or near visual acuity < N10 binocularly with Bailey-Lovie word reading chart and/or visual field 20° or < 20° from the point of fixation. The data collected included age, gender, diagnosis, extent of visual field loss (mean deviation and central residual field of vision), type of visual disability, and the type of low vision aid preferred by the patients for daily routine use. Statistics: Multivariate logistic regression was used to assess the association between different variables influencing preference of particular LVD. Results: The mean age of patients (n = 67) was 50 ± 22.7 (9-83 years) which included 21 developmental (31%), 11 primary angle closure glaucoma (16%) and 35 primary open angle glaucoma (52%) with 61% older than 50 years. On multivariate regression, age < 30 years (β = −0.04, P = 0.005), color matching disability (β = 3.08, P = 0.002), glare (β = 2.04, P < 0.001) were significant influences for preference for electronic LVD. Conclusions: Younger patients < 30 years with glare and color contrast impairment may be prescribed electronic LVDs for optimal visual function.

Migraine and Vasospasm in Glaucoma: Age-Related Evaluation of 2027 Patients With Glaucoma or Ocular Hypertension.

To evaluate frequency of migraine, vasospasm (VS), family history (FH) of migraine, and family history of glaucoma (FHG) in different types of glaucoma in relation to age and stage of visual field loss (VFL) at diagnosis. A total of 2170 patients with glaucoma or ocular hypertension (OH) were interviewed by using standardized questions concerning FHG, age at diagnosis, and potential risk factors, including migraine and VS. Of 2027 patients providing information on migraine, 1244 had primary open-angle glaucoma (POAG), 140 normal tension glaucoma (NTG), 49 pigmentary glaucoma, 64 pseudoexfoliation glaucoma (PEX), 138 OH, and 218 primary angle closure glaucoma (PACG). Of all patients, 13.7% reported migraine, 19.0% VS, 30.8% FH of migraine, and 40.3% FHG. Patients with FHG had a significantly higher frequency of migraine than patients without FHG (15.7% vs. 12.3%, P = 0.02). Migraine was significantly more frequent in NTG (21.4%) than POAG (13.1%; P = 0.01), PEX (7.8%; P = 0.02), and PACG (10.1%; P = 0.004). Compared to patients with POAG, patients with NTG had a 63.5% higher age-corrected probability for migraine (P = 0.007). There was no evidence for migraine or VS being prognostic factors regarding the extent of VFL at diagnosis. Migraine and VS were significantly more frequent in females. The higher frequency of migraine and VS in females could contribute to the female preponderance in NTG. Our findings suggest an association of NTG and migraine and a common, possibly polygenetic, vascular etiology of these two diseases both with familial predisposition.

An introduction to patient-reported outcome measures in ophthalmic research

Clinical outcomes, such as quantifying the extent of visual field loss by automated perimetry, are valued highly by health professionals, but such measures do not capture the impact of the condition on a patient's life. Patient-reported outcomes describe any report or measure of health reported by the patient, without external interpretation by a clinician or researcher. In this review, we discuss the value of the measures that capture this information (patient-reported outcome measures; PROMs), and why they are important to both the clinician and the researcher. We also consider issues around developing or selecting a PROM for ophthalmic research, the emerging challenges around conducting and reporting PROMs in clinical trials and highlight best practice for their use. Search terms for this review comprised: (1) (patient-reported outcomes OR patient-reported outcome measures) AND (2) randomised controlled trials AND (3) limited to ophthalmic conditions. These terms were expanded as follows: ((('patients'(MeSH Terms) OR 'patients'(All Fields) OR 'patient'(All Fields)) AND ('research report'(MeSH Terms) OR ('research'(All Fields) AND 'report'(All Fields)) OR 'research report'(All Fields) OR 'reported'(All Fields)) AND outcomes(All Fields)) OR (('patients'(MeSH Terms) OR 'patients'(All Fields) OR 'patient'(All Fields)) AND ('research report'(MeSH Terms) OR ('research'(All Fields) AND 'report'(All Fields)) OR 'research report'(All Fields) OR 'reported'(All Fields) AND ('outcome assessment (health care)'(MeSH Terms) OR ('outcome'(All Fields) AND 'assessment'(All Fields) AND '(health'(All Fields) AND 'care)'(All Fields)) OR 'outcome assessment (health care)'(All Fields) OR ('outcome'(All Fields) AND 'measures'(All Fields)) OR 'outcome measures'(All Fields)))) AND ('randomized controlled trial'(Publication Type) OR 'randomized controlled trials as topic'(MeSH Terms) OR 'randomised controlled trials'(All Fields) OR 'randomized controlled trials'(All Fields)) AND (ophth*(All Fields)). The authors also utilised the extensive non-ophthalmic literature and online resources relating to PROs and PROMs to inform this review.

Prevalence and Severity of Undetected Manifest Glaucoma: Results from the Early Manifest Glaucoma Trial Screening

To estimate the prevalence and severity of undetected glaucoma in the population. Cross-sectional study. A total of 32 918 subjects aged 55 to 79 years from Malmö, Sweden, who were screened between 1992 and 1997. All subjects in the screened age groups living in the catchment area, and for whom there were no recent records at the Malmö University Hospital Ophthalmology department, were invited. The main purpose of the screening was to recruit subjects for the Early Manifest Glaucoma Trial. We registered the age, sex, and amount of visual field loss in subjects with previously undiagnosed glaucoma identified at the screening. The disease was categorized into 5 stages based on perimetric mean deviation values. Prevalence of undetected glaucoma at various disease stages in different age groups expressed as percentages. Among the screened subjects, who were 77.5% of all invited subjects, a total of 406 subjects (1.23%) were identified with previously undetected glaucoma. Prevalence increased with age, from 0.55% at 55 to 59 years to 2.73% at 75 to 79 years. Unilateral disease accounted for 66% of all cases. Extent of visual field loss was similar in all age groups from 60 years and more. Most eyes had early (35%) or moderate (31%) glaucomatous visual field defects, but 134 subjects (33%) had advanced visual field loss in at least 1 eye. No subject was blind in both eyes, but 3.4% of the newly diagnosed patients were unilaterally blind because of glaucoma. Prevalence of undetected glaucoma increased with age, whereas disease severity did not increase in subjects older than 60 years of age. One third of subjects with previously undetected glaucoma had advanced or later-stage disease in at least 1 eye. Unilaterally blind subjects were present in all age groups. Proprietary or commercial disclosure may be found after the references.

Psychological distress is associated with vision-related but not with generic quality of life in patients with visual field defects after cerebral lesions.

Considerably diminished quality of life (QoL) is observed in patients with visual field defects after lesions affecting the visual pathway. But little is known to what extent vision-and health-related QoL impairments are associated with psychological distress. In 24 patients with chronic visual field defects (mean age=56.17±12.36) the National Eye Institute-visual functioning questionnaire (NEI-VFQ) for vision-related QoL, the Short Form Health Survey-36 (SF-36) for generic QoL and the revised Symptom-Checklist (SCL-90-R) were administered. Cases with clinically relevant SCL-90-R symptoms were defined. Demographic, QoL and visual field parameters were correlated with SCL-90-R scales. About 40% of the investigated patients met the criteria for the definition of psychiatric caseness. 8/12 NEI-VFQ scales correlated significantly with SCL-90-R phobic anxiety (r-range −0.41 to −0.64, P<0.05), 5/12 NEI-VFQ scales correlated with SCL-90-R interpersonal sensitivity (−0.43 to −0.50), and 3/12 with SCL-90-R depression (−0.51 to −0.57) and obsessive-compulsiveness (−0.41 to −0.43). In contrast, only 1/8 SF-36 scales correlated significantly with SCL-90-R depression, phobic anxiety and interpersonal sensitivity (−0.41 to −0.54). No substantial correlations were observed between visual field parameters and SCL-90-R scales. Significant correlations of SCL-90-R with NEI-VFQ but not with SF-36 suggest that self-rated psychological distress is the result of diminished vision-related QoL as a consequence of visual field loss. The extent of visual field loss itself did not influence the rating of psychological distress directly, since SCL-90-R symptoms were only reported when diminished vision-related QoL was present. Patients with reduced vision-related QoL due to persisting visual field defects should therefore be offered additional neuropsychological rehabilitation and supportive psychotherapeutic interventions even years after the lesion.

Visual field loss in children with craniosynostosis

To identify visual field deficits in a group of children with syndromic craniosynostosis. Kinetic visual field examination and visual evoked potentials (VEPs) were recorded in 16 children with syndromic craniosynostosis as part of their ophthalmic evaluation. VEPs were analyzed for inter-hemispheric asymmetries and component amplitude and latency, while visual fields were analyzed both qualitatively and quantitatively. All children with craniosynostosis were found to have visual field deficits compared to controls. In the Crouzon group, deficits tended to involve the nasal field, while infero-nasal field deficits were the most consistent finding in children with Apert syndrome. Children with Pfeiffer's demonstrated the greatest deficits, with severe constrictions affecting the whole visual field. VEPs were asymmetrical in four cases while the P100 component was subnormal in ten of the 16 patients for either amplitude and/or latency. Although we may speculate about the mechanisms that cause visual field deficits, we currently are unable to explain the reason for the differing types and extent of visual field loss in the different syndromic groups. We can conclude that the visual field deficits do indicate previous or ongoing visual dysfunction that cannot be monitored employing central vision tests alone.

Retinal nerve fiber layer thickness in Vigabatrin‐exposed patients

Vigabatrin-associated visual field loss (VAVFL) occurs in 25 to 50% of exposed patients and is routinely monitored using perimetry, which has inherent limitations. Using optical coherence tomography (OCT), retinal nerve fiber layer (RNFL) thinning has been described in a small number of vigabatrin-exposed patients. We explored the relationship between RNFL thickness and visual field size, to determine whether OCT is a suitable tool to use in patients exposed to vigabatrin. Two hundred one vigabatrin-exposed subjects with epilepsy, divided into 2 groups, and 90 healthy controls participated. Visual fields were obtained using Goldmann kinetic perimetry and quantified using mean radial degrees (MRD). RNFL imaging was performed using either spectral-domain (Group 1) or time-domain (Group 2) OCT. Thirty-nine of 201 (19.4%) patients were unable to perform perimetry. Thirteen (6.5%) patients were unable to perform OCT. A total of 51.6% of patients showed VAVFL. Average RNFL thickness was significantly thinner in patients (77.9 μm) compared to healthy controls (93.6 μm) (p < 0.001). There was a strong correlation between MRD and average RNFL thickness for Group 1 (r = 0.768, p < 0.001) and Group 2 (r = 0.814, p < 0.001). OCT RNFL imaging showed high repeatability. OCT provides a useful tool to assess people exposed to vigabatrin, and can provide an accurate estimate of the extent of visual field loss in the absence of a reliable direct measure of the visual field. The strong linear relationship found between RNFL thickness and visual field size provides some evidence that irreversible VAVFL may be related to loss of retinal ganglion cell axons.

The influence of socioeconomic and clinical factors upon the presenting visual field status of patients with glaucoma

To investigate the relationship between socioeconomic status and the extent of visual field loss in POAG and treated OHT patients at their first presentation to Manchester Royal Eye Hospital. A cohort of 113 glaucoma patients seen between 1995 and 2005 was reviewed. The clinical parameters intraocular pressure, C : D ratio, family history of glaucoma, visual acuity, extent of visual field loss, and demographic parameters: age, gender, ethnicity, and residential postcode were extracted from hospital records. The socioeconomic status of each patient was estimated from the patient's residential postcode with the ACORN index (group 1: affluent and group 2: socioeconomically deprived). In comparison to group 1 (n=49), patients in group 2 (n=64) presented with more advanced field loss, lower educational attainment (18 vs 98% with no or unknown qualification), and were less aware of glaucoma in the family (27 vs 17%). Patients with a number of systemic health problems had worse vision, more severe visual field loss, and worse clinical attendance (P<0.05). The extent of visual field loss in glaucoma patients at first presentation is related to a combination of clinical and socioeconomic factors including the patient's postcode. This finding could be used to target future case-finding resources.

Visual fields in patients who have undergone vitrectomy for complications of diabetic retinopathy. A prospective study

BackroundTo determine the extent of visual field loss in patients who had required a pars plana vitrectomy secondary to complications of proliferative diabetic retinopathy.MethodsPatients that had undergone a vitrectomy on at least one eye for treatment of either vitreous haemorrhage or tractional retinal detachment were selected for study. ETDRS acuity and Humphrey binocular Esterman visual field testing were performed and compared to the minimum standards for safe driving as defined by the Royal College of Ophthalmologists in 1999. In addition to this Goldman kinetic visual fields using a III4e and V4e stimulus size and central 24-2 threshold test with the SITA-fast strategy were performed on the vitrectomised eye.Results20 patients (n = 20) were recruited. Mean visual acuity in the eye being tested was 0.20 (Snellen 6/9.5). Results from the Humphrey field analyzer showed a mean number of abnormal stimulus locations of 71.2% (p < 0.005). 70% of patients had sufficient binocular acuity to drive and of these 71.4% were shown not to have a minimum visual field for safe driving on binocular Esterman field analysis.ConclusionVitrectomy potentially allows retention/restoration of good visual acuity in patients with complications of proliferative diabetic retinopathy. However patients may be suffering from unrecognized visual impairment consequent upon extensive visual field loss which in over two thirds of patients may be sufficiently severe to preclude safe driving.

The Impact of Visual Field Loss on Driving Performance: Evidence From On-Road Driving Assessments

The purpose of this study was to investigate the relationship between visual field loss and driving performance as determined by on-road driving assessments. We reviewed the files of 1350 patients enrolled in a rehabilitation program at the Bloorview MacMillan Rehabilitation Centre, Toronto, Canada. We identified 131 patients with visual field loss who had undergone an on-road driving assessment. These patients had a primary diagnosis of visual impairment or a primary diagnosis of cerebral vascular accident (CVA) with a secondary diagnosis of visual impairment. None of these patients had documentation of neglect, substantial motor or cognitive deficits. We report the data obtained from 13 hemianopics, 7 quadrantanopics, 25 patients with monocular vision, 10 patients with moderate peripheral losses (<135 degrees of horizontal visual field measured at the midline), and 76 patients with mild peripheral losses (between 135 degrees and 186 degrees of horizontal visual field). The on-road assessment consisted of driving in the area surrounding the rehabilitation center, and the outcome was based on performance on a number of tasks commonly encountered in daily driving. For the purposes of this study, the assessment outcomes were classified as safe, unknown, or unsafe. Overall, the extent of visual field loss did not have a significant impact on driving performance (chi2 = 4.37, p = 0.358). However, hemianopia tended to have a worse impact on driving performance than quadrantanopia with a marginally significant result (chi2 = 3.33, p = 0.068). Overall, the location of the visual loss was not significantly related to driving fitness (chi2 = 1.05, p = 0.30). However, localized defects in the left hemifield (chi2 = 9.561, p = 0.002) and diffuse visual loss in the right hemifield (chi2 = 10.395, p = 0.001) seemed to be associated with driving impairments. A large proportion of monocular drivers were safe drivers and the location of their deficit had no significant impact. Although the extent of visual field defects appears to be related to driving performance as determined by an on-road driving assessment, large individual differences were observed. This highlights the need for individualized on-road assessments for patients with visual field defects.

Vigabatrin: longterm follow-up of electrophysiology and visual field examinations.

To report the results of repeated electrophysiological and visual field examinations in patients with vigabatrin-associated visual field loss (VGB-VFL) and the relationship between these electrophysiological findings, the cumulative dose of vigabatrin and the extent of visual field loss. Twenty-two eyes of 11 patients with VGB-VFL were studied. All patients underwent surgery for therapy-resistant epilepsy. Repeated electro-oculograms (EOGs) and flash electroretinograms (ERGs) were made and the cumulative dose of vigabatrin and the visual field loss were recorded after a period of 37-47 months. The visual field loss was stable in patients who had stopped vigabatrin at the time of the first examination. There was a slight increase in VFL in patients who continued vigabatrin. During the second EOG and ERG, abnormalities in scotopic and photopic a-wave latencies and in scotopic b-wave amplitude were found in more than 50% of patients. Only b-wave latency became normal, while EOG, a-wave latency, a-wave amplitude and b-wave amplitude stayed abnormal. The amount of VFL and the cumulative dose of vigabatrin were statistically correlated with the b-wave amplitude, mainly photopic, found during the first and second examinations. After 4 years, EOG, flash ERG and visual field loss had not improved in patients with VGB-VFL. The statistically significant correlation found during the first examination between the amount of VFL and the cumulative dose of vigabatrin with the (mainly photopic) b-wave amplitude remained constant.

Neuro-ophthalmologic findings in konzo, an upper motor neuron disorder in Africa.

To investigate the neuro-ophthalmological manifestations in konzo, a non-progressive symmetric spastic para/tetraparesis of acute onset associated with consumption of insufficiently processed bitter cassava roots combined with a low protein intake. Twenty-one Congolese konzo patients underwent neuro-ophthalmological investigations including visual acuity testing, assessment of light pupillary reflexes, evaluation of ocular motility and deviation, direct ophthalmoscopy, and visual field perimetry. Objective refraction including retinoscopy and keratometry, and slit-lamp biomicroscopy were also done. Five patients had visual impairment, and 14 had temporal pallor of the optic disc. Fourteen presented visual field defects, the most frequent being concentric constriction and peripheral defects. Overall, 11 subjects had symptoms qualifying for the diagnosis of optic neuropathy. Two had spontaneous pendular nystagmus in primary position of gaze. Visual field defects and pallor of the optic discs were found in mild, moderate and severe forms of konzo. No correlation was found between the severity of the motor disability of konzo and the extent of visual field loss. Konzo was associated with optic neuropathy and a few patients had nystagmus. Although the etiopathogenesis of this optic neuropathy remains to be elucidated, the symmetry of the involvement suggests a toxic origin. We suggest that cyanide causes the neuro-ophthalmological damage in konzo. However, the optic neuropathy in konzo patients does not resemble the features of the epidemic optic neuropathy in Tanzania, Cuba or Nigeria, Leber's hereditary optic neuropathy, tobacco amblyopia or vitamin B deficiency.