Perimetric Visual Field Research Articles

A Noninvasive Clinical Method to Measure in Vivo Mechanical Strains of the Lamina Cribrosa by OCT

To measure mechanical strain of the lamina cribrosa (LC) after intraocular pressure (IOP) change produced 1 week after a change in glaucoma medication. Cohort study. Adult glaucoma patients (23 eyes, 15 patients) prescribed a change in IOP-lowering medication. Noninvasive OCT imaging of the eye. Deformation calculated by digital volume correlation of OCT scans of the LC before and after IOP lowering by medication. Among 23 eyes, 17 eyes of 12 persons had IOP lowering ≥ 3 mmHg (reduced IOP group) with tensile anterior-posterior Ezz strain= 1.0% ± 1.1% (P= 0.003) and compressive radial strain (Err)=-0.3% ± 0.5% (P= 0.012; random effects models accounting inclusion of both eyes in some persons). Maximum in-plane principal (tensile) strain and maximum shear strain in the reduced-IOP group were as follows: Emax= 1.7% ± 1.0% and Γmax= 1.4% ± 0.7%, respectively (both P < 0.0001 vs. zero). Reduced-IOP group strains Emax and Γmax were significantly larger with greater % IOP decrease (P < 0.0001 and P < 0.0001, respectively). The compliances of the Ezz, Emax, and Γmax strain responses, defined as strain normalized by the IOP decrease, were larger with more abnormal perimetric mean deviation or visual field index values (all P ≤ 0.02). Strains were unrelated to age (all P ≥ 0.088). In reduced-IOP eyes, mean LC anterior border posterior movement was only 2.05 μm posteriorly (P= 0.052) and not related to % IOP change (P= 0.94, random effects models). Only Err was significantly related to anterior lamina depth change, becoming more negative with greater posterior LC border change (P= 0.015). Lamina cribrosa mechanical strains can be effectively measured by changes in eye drop medication using OCT and are related to degree of visual function loss in glaucoma. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparison of disease severity in glaucoma patients identified byscreening in the 1990s and in routine clinical care in the 2010s in Sweden.

In a previous study comparing the amount of visual field damage at presentation in patients having open-angle glaucoma (OAG) identified through screening and in patients diagnosed in routine clinical practice in the 1990s, the damage was considerably worse in the clinically diagnosed patients. In the present study we compare visual field damage at presentation in the same 402 screened patients with that seen in 281 newly detected previously untreated patients clinically diagnosed in the 2010s. The perimetric visual field index mean deviation (MD) was compared in the two groups of patients. In the clinical patients diagnosed with bilateral visual field damage the median MD was -5.1 dB in the better eye and -13.0 dB in the worse eye. In the screened patients the median MD in the better eye was -6.5 dB and -11.5 dB in the worse eye. The differences between the clinical and screened patients were non-significant, p = 0.28 and p = 0.67 respectively. More clinical patients had severe visual field loss, defined as MD less than -20 dB, in the worse eye than in the screened patients, 18.5% versus 12.7% respectively, p = 0.037. The visual field damage at presentation in clinically diagnosed OAG patients has improved in the past 20 years, but the proportion of patients with severe visual field loss in at least one eye, almost 20%, is still unacceptably high considering that severe visual field damage at presentation is the most important risk factor for later development of glaucoma blindness.

Comparison of perimetric 24-2 and 30-2 test patterns in detecting visual field defects in patients with tumours in the pituitary region.

Automated perimetry provides a standardized method of measuring the visual field. The Humphrey Field Analyser (HFA) uses the 24-2 test pattern to cover 24 degrees centrally or the 30-2 test pattern to cover a slightly broader region of 30 degrees. The aim of this study was to determine whether the 24-2 test pattern provides comparable information to the 30-2 test pattern in detecting visual field defects in patients with tumours in the pituitary region. A retrospective cohort study was carried out on patients with tumours in the pituitary region and radiologically confirmed compression of the visual pathway. Included patients (79 of 133) had been examined using the Humphrey 30-2 visual field test, after which the 30-2 test patterns were reduced into corresponding 24-2 test patterns. The location of visual field defects, visual acuity and the perimetric parameters mean deviation (MD) and visual field index (VFI) were also recorded. No patient was classified differently when evaluated with the 24-2 test pattern, compared to the 30-2 test pattern. Interestingly, although the majority of patients had visual field defects located in the temporal visual field of each eye, a significant minority did not. In addition, it was found that a large proportion of patients had normal visual acuity (≥0.8). The use of the HFA 24-2 test pattern reliably detected visual field defects in patients with tumours in the pituitary region. The present study indicates that MD and VFI are not reliable parameters for evaluating visual field defects due to compression.

Fundus imaging and perimetry in patients with idiopathic intracranial hypertension - an intermethod and interrater validity study.

There is a need to improve the diagnostic process of patients suspected of papilledema. In patients with known or suspected idiopathic intracranial hypertension we validated a fundus imaging and perimetric visual field assessment system (COMPASS) performed at a headache centre in comparison to an assessment (Topcon plus OCTOPUS) at a neuroophthalmological clinic. For intermethod assessment, blinded fundus images and perimetry from COMPASS versus Topcon plus OCTOPUS were assessed by a neuroophthalmologist. For interrater assessment, fundus images and perimetry obtained by the COMPASS system were assessed by an untrained medical doctor, a trained neurologist and a trained medical student and compared to the neuroophthalmologist's assessments. For the intermethod variation of presence of papilledema on fundus images, a kappa value of 0.60, sensitivity of 87% and specificity of 73% were found. The interrater variation of presence of papilledema on fundus images showed kappa values ranging from 0.43 - 0.74, sensitivity values ranging from 69.8% - 96.2% and specificity values ranging from 45.6% - 93.4% when comparing the assessments made by the headache centre staff with neuroophthalmologist's assessments. The COMPASS showed a 59% sensitivity and moderate agreement in detecting visual field defects compared with OCTOPUS. The visual field assessment showed only slight to fair agreement from 0.19 - 0.31 between assessments made by the headache center staff and the neuroophthalmologist. The COMPASS system can be used with reasonable sensitivity in the assessment of papilledema in patients suspected of IIH at a tertiary headache centre.

Functional preservation and enhanced capacity for visual restoration in subacute occipital stroke.

Stroke damage to the primary visual cortex (V1) causes a loss of vision known as hemianopia or cortically-induced blindness. While perimetric visual field improvements can occur spontaneously in the first few months post-stroke, by 6 months post-stroke, the deficit is considered chronic and permanent. Despite evidence from sensorimotor stroke showing that early injury responses heighten neuroplastic potential, to date, visual rehabilitation research has focused on patients with chronic cortically-induced blindness. Consequently, little is known about the functional properties of the post-stroke visual system in the subacute period, nor do we know if these properties can be harnessed to enhance visual recovery. Here, for the first time, we show that 'conscious' visual discrimination abilities are often preserved inside subacute, perimetrically-defined blind fields, but they disappear by ∼6 months post-stroke. Complementing this discovery, we now show that training initiated subacutely can recover global motion discrimination and integration, as well as luminance detection perimetry, just as it does in chronic cortically-induced blindness. However, subacute recovery was attained six times faster; it also generalized to deeper, untrained regions of the blind field, and to other (untrained) aspects of motion perception, preventing their degradation upon reaching the chronic period. In contrast, untrained subacutes exhibited spontaneous improvements in luminance detection perimetry, but spontaneous recovery of motion discriminations was never observed. Thus, in cortically-induced blindness, the early post-stroke period appears characterized by gradual-rather than sudden-loss of visual processing. Subacute training stops this degradation, and is far more efficient at eliciting recovery than identical training in the chronic period. Finally, spontaneous visual improvements in subacutes were restricted to luminance detection; discrimination abilities only recovered following deliberate training. Our findings suggest that after V1 damage, rather than waiting for vision to stabilize, early training interventions may be key to maximize the system's potential for recovery.

Personality and stress influence vision restoration and recovery in glaucoma and optic neuropathy following alternating current stimulation: implications for personalized neuromodulation and rehabilitation

PurposeIdentifying factors that affect recovery or restoration of neurological function is a key goal of rehabilitation in neurology and ophthalmology. One such factor can be prolonged mental stress, which may be not only the consequence of nervous system damage but also a major risk factor, or cause, of neural inactivation. Using the visual system as a model of neural injury, we wished to study how patients’ stress and personality profiles correlate with vision recovery as induced by therapy with alternating current stimulation (ACS) in patients with optic nerve damage.MethodsPersonality and stress questionnaires were sent retrospectively to a clinical convenience sample of patients who suffer low vision due to optic nerve damage, which had previously been treated with ACS. The questionnaires included the NEO Five-Factor Inventory (NEO-FFI), the Trier Inventory of Chronic Stress (TICS), and the Flammer syndrome (FS) checklist, which probes signs of vascular dysregulation (VD). These scores were then correlated with the extent of ACS-induced vision restoration as recorded 1–3 years earlier by perimetric visual field tests.ResultsTwo NEO-FFI personality factors (lower neuroticism, higher conscientiousness) and the presence of physiological Flammer signs were associated with greater recovery as were individual items of the factors openness and agreeableness. Single NEO-FFI item analysis revealed that recovery relates to greater extraversion (optimistic and happy), openness (less guided by authorities for decisions on moral issues), and agreeableness (argue less, like working with others, thoughtful, considerate) as well as the presence of FS signs (cold hands/feet, hypotension, slim body shapes, tinnitus). This suggests that patients with better recovery were more calm, peaceful and secure, hard-working, and reliable, and with high organizational skills. In contrast, patients with poor recovery had a tendency to be emotionally unstable, anxious, unhappy and prone to negative emotions, impulsive, careless, and unorganized. Chronic stress assessed with TICS did not correlate with recovery.ConclusionVision restoration induced by ACS is greater in patients with less stress-prone personality traits and those who show signs of VD. Prospective studies are now needed to determine if personality has (i) a causal influence, i.e., patients with less stress-prone personalities and greater VD signs recover better, and/or (ii) if personality changes are an effect of the treatment, i.e., successful recovery induces personality changes. Though the cause-effect relationship is still open, we nevertheless propose that psychosocial factors and VD contribute to the highly variable outcome of vision restoration treatments in low vision rehabilitation. This has implications for preventive and personalized vision restoration and is of general value for our understanding of outcome variability in neuromodulation and neurological rehabilitation.

Prognostic importance of endothelin-1 and endothelin receptor: a plasma levels in the early perimetric stage of primary open-angle glaucoma

An increasing amount of data suggests a role of the eye vascular system and oxidative stress in glaucoma pathogenesis. Reports have suggested endothelin-1 (ET-1) and its receptor (ETR-A) as possible glaucoma biomarkers. This study explored the diagnostic and prognostic abilities of ET-1 and ETR-A plasma concentrations in primary open angle glaucoma (POAG). Seventy-five participants were divided into three groups: controls, early and advanced POAG stage, graded by a perimetric visual field test. All of them underwent a standard ophthalmological examination including optical coherence tomography. The statistical analysis showed a significant difference between the ET-1 values in the controls (4.88 ± 1.75 pg/mL) and the glaucoma patients, but lack of statistical significance in the glaucoma severity (early POAG: 6.33 ± 2.38 pg/mL and advanced POAG: 6.34 ± 1.56 pg/mL). The mean ETR-A values were significantly different between the three groups (controls 1209.28 ± 314.48 pg/mL, early POAG: 673.44 ± 283.02 pg/mL and advanced POAG: 992.28 ± 264.22 pg/mL). Two mathematical models were developed concerning the two perimetric indices (MD/PSD) and ETR-A in the early glaucoma group. ETR-A showed a very high diagnostic accuracy. Only ETR-A had significant diagnostic ability for advanced glaucoma after the comparison between the two glaucoma groups. Every 1 pg/mL increase in the ET-1 plasma concentration increased the possibility for early glaucoma changes by 2.124 times, whereas every 1 pg/mL increase in the ETR-A level decreased this possibility by 1%. Our results indicate that ET-1 and ETR-A could be two very good diagnostic parameters for early POAG changes.

Natural progression of perimetric visual field defects after V1 stroke

Natural progression of perimetric visual field defects after V1 stroke

Glaucoma: Confrontation visual field test using Bagolini striated glasses — a new screening method for detecting visual field defects

INTRODUCTION. Glaucoma diagnosis is based on elevated intraocular pressure, altered morphology of the optic disc, and perimetric visual field defects. Next to funduscopy and optical coherence tomography, perimetric data are important. In developing countries, large parts of the population have only limited access to medical care. Especially in these cases, a quick and affordable method for detecting visual field defects would be desirable. The aim of this study was to investigate the potential use of Bagolini striated glasses in detecting glaucomatous visual field defects. MATERIALS AND METHODS . Ninety subjects of the Erlangen Glaucoma Register (ISSN 2191-5008, CS-2011. ClinicalTrials.gov, Identifier: NCT00494923) were tested using the confrontation visual field test with Bagolini striated glasses [10 normals, 17 ocular hypertensions (OHT), 31 preperimetric open-angle glaucomas (preOAG), 16 normal tension glaucomas (NTG), 16 open-angle glaucomas (OAG)]. All probands underwent standard ophthalmological examination including slit-lamp biomicroscopy, funduscopy, and Goldmann-tonometry. Additionally, standard white-on-white perimetry and measurements of the global retinal nerve fibre layer (RNFL) of the optic disc were performed. RESULTS. 1. All normals, all OHTs, and 96% of preOAGs showed normal Bagolini test results. 2. 74% of NTGs and 73% of OAGs yielded pathological Bagolini test results. 3. Specificity of patients with normal visual fields was 98% and sensitivity was 73–80%. 4. Visual field defects resulted in altered Bagolini test results. 5. Localised visual field defects were detected in 78% (NTG) and 80% (OAG) using Bagolini striated glasses. CONCLUSIONS. Glaucoma-related visual field defects can be detected by confrontation visual field testing using Bagolini striated glasses. This quick, easily performed, and affordable method can be used as a bedside test and is suitable as a screening method for persons in developing countries.

A matter of time: improvement of visual temporal processing during training-induced restoration of light detection performance.

The issue of how basic sensory and temporal processing are related is still unresolved. We studied temporal processing, as assessed by simple visual reaction times (RT) and double-pulse resolution (DPR), in patients with partial vision loss after visual pathway lesions and investigated whether vision restoration training (VRT), a training program designed to improve light detection performance, would also affect temporal processing. Perimetric and campimetric visual field tests as well as maps of DPR thresholds and RT were acquired before and after a 3 months training period with VRT. Patient performance was compared to that of age-matched healthy subjects. Intact visual field size increased during training. Averaged across the entire visual field, DPR remained constant while RT improved slightly. However, in transition zones between the blind and intact areas (areas of residual vision) where patients had shown between 20 and 80% of stimulus detection probability in pre-training visual field tests, both DPR and RT improved markedly. The magnitude of improvement depended on the defect depth (or degree of intactness) of the respective region at baseline. Inter-individual training outcome variability was very high, with some patients showing little change and others showing performance approaching that of healthy controls. Training-induced improvement of light detection in patients with visual field loss thus generalized to dynamic visual functions. The findings suggest that similar neural mechanisms may underlie the impairment and subsequent training-induced functional recovery of both light detection and temporal processing.

Wearable technology with head-mounted displays and visual function.

Letters RESEARCH LETTER Wearable Technology With Head-Mounted Displays and Visual Function Interest in wearable head-mounted display systems for gen- eral consumers is increasing, with multiple models in production. 1 However, their effect on vision is largely un- known. Peripheral visual field is a main component of vision and essential for daily activities such as driving, pedestrian safety, and sports. Conventional spectacle frames can reduce visual field, sometimes causing absolute scotomas (blind spots), 2 and head- mounted devices have even more pronounced frames. To quantify their effect on visual function, we compared perfor- mance on perimetric visual field tests with a head-mounted device vs regular eyewear. Methods | Three healthy emmetropic or refractively corrected individuals with 20/20 best-corrected visual acuity and nor- mal baseline visual fields were tested in April 2014. Partici- pants used a wearable device (Google Glass, Google Inc), fol- lowing manufacturer’s instructions, for a 60-minute acclimation period. Participants required minor adjustments to optimize screen visibility. To assess obstruction potential, the display prism’s position relative to the right eye pupillary axis was graded as (1) over central pupillary axis; (2) above cen- tral pupillary axis but inferior to superior limbus; or (3) above superior limbus. Immediately thereafter, participants underwent 30-2 and 60-4 threshold perimetric (visual field) testing with the Hum- phrey Visual Field Analyzer II-750i (Carl Zeiss Meditec). Test- ing was performed first with the device (with software deac- tivated to avoid distractions), followed by a control frame of similar color and temple width. The University of California, San Francisco, determined the study was exempt from insti- tutional review board review. To assess how the devices are worn by general consum- ers, photographs of people wearing the product and facing the camera, obtained from an Internet search conducted on May 1, 2014, were analyzed. 3 The image search included the term Google Glass. The full output of images was reviewed, includ- ing images posted by companies and individuals. Photo- graphs were assessed for prism position relative to the pupil with the grading system described above. Results | Figure 1 shows the baseline characteristics of partici- pants. Visual field testing demonstrated significant scotomas in all 3 participants while wearing the device (Figure 2; note variations in wearing and head position). In all 3 cases, more than 10° of visual field in the horizontal axis were subtended. Scotoma was absent with control perimetry testing with the regular frame. For the image analysis, 311 images were found, with 132 eli- gible for evaluation. The prism covered the pupillary axis in 29.5%, covered the eye but not the axis in 29.5%, and was su- perior to the limbus in 41%. Therefore, 59% had the prism in a position likely to interfere with vision. Discussion | To our knowledge, this is the first evaluation of the effect of wearable electronics with head-mounted display on vision. The device created a clinically meaningful visual field obstruction in the upper right quadrant. Defects were in- duced by the frame hardware design only and were not re- lated to a distracting effect of software-related interference. Image analysis further demonstrated that many people wear the device near or overlapping their pupillary axis, which may induce scotomas and interfere with daily function. This study is limited by the small number of participants, who may not be representative of all users. Even though the scotomas were easily identifiable, a larger sample is needed to identify factors that influence scotoma size and depth. The Figure 1. Baseline Characteristics of Participants Age, y Participant 1 Participant 2 Participant 3 Sex Male Male Male Race White Pacific Islander Asian Refraction oculus dexter (OD) a Plano Plano Best corrected visual acuity OD a Prism placed over the central pupillary axis Prism cleared the central pupillary axis but was inferior to the superior limbus Prism placed over the central pupillary axis Pupillary distance, mm Wearable device prism position a jama.com jamanetwork/2014/jama/05nov2014/jld140032 Indicates the right eye. JAMA November 5, 2014 Volume 312, Number 17 PAGE: right 1 SESS: 24 OUTPUT: Oct 17 11:34 2014

Objective perimetry using a four-channel multifocal VEP system: correlation with conventional perimetry and thickness of the retinal nerve fibre layer

PurposeThere is evidence that multifocal visual evoked potentials (VEPs) can be used as an objective tool to detect visual field loss. The aim of this study was to correlate multifocal...

Objective visual field determination in forensic ophthalmology with an optimized 4-channel multifocal VEP perimetry system: a case report of a patient with retinitis pigmentosa

We present the case of a 59-year-old male patient with progressive vision impairment and consecutive visual field narrowing ("tunnel view") for 7years and a known retinitis pigmentosa for 5years. The remaining Goldmann perimetric visual field at time reported was less than 5°. A request for blindness-related social benefits was rejected because an ophthalmologic expert assessment suggested malingering. This prompted us to assess an objective determination of the visual field using multifocal VEPs. Objective visual field recordings were performed with a four-channel multifocal VEP-perimeter using 58 stimulus fields (pattern reversal dartboard stimulus configuration). The correlated signal data were processed using an off-line method. At each field, the recording from the channel with the maximal signal-to-noise ratio (SNR) was retained, thus resulting in an SNR optimized virtual recording. Analysis of VEP signals was performed for each single field and concentric rings and compared to an average response measured in five healthy subjects. Substantial VEP responses could be identified in three fields within the innermost ring (eccentricity, 1.7°) for both eyes, although SNR was generally low. More eccentric stimuli did not elicit reliable VEP responses. The mfVEP recording was correlated with perimetric visual field data. The current SNR optimization by using the channel with the largest SNR provides a good method to extract useful data from recordings and may be appropriate for the use in forensic ophthalmology.

Stimulus Parameters for Goldmann Kinetic Perimetry in Nonorganic Visual Loss

Objective: To investigate the influence of the stimulus parameters on perimetry at various distances and draw conclusions for the clinical exploration of nonorganic visual loss. Methods: Visual field testing using Goldmann kinetic perimetry was performed on 15 healthy volunteers. The I/1e isopter at 33 cm was compared to the I/1e, II/1e and I/2e isopters at 66 cm. The 0/1e isopter at 33 cm was compared to the 0/1e, I/1e and 0/2e isopters at 66 cm. Results: Doubling the examination distance without adjusting the stimulus parameters resulted in significant perimetric visual field constriction. Doubling the stimulus diameter resulted in perimetric visual field expansion by a factor of 2.26 and 3.32 for I/1e and 0/1e, respectively. Increasing stimulus luminance by a factor of 3.17 caused expansion by a factor of 2.15 and 2.32 for I/1e and 0/1e, respectively. Conclusions: To avoid falsely diagnosing visual field constriction, stimulus parameters need to be adjusted when visual field testing is performed at double distance. Increasing stimulus luminance was more appropriate than augmenting stimulus size.

Current trends in the treatment of infantile spasms

Infantile spasms are an epilepsy syndrome with distinctive features, including age onset during infancy, characteristic epileptic spasms, and specific electroencephalographic patterns (interictal hypsarrhythmia and ictal voltage suppression). Adrenocorticotropic hormone (ACTH) was first employed to treat infantile spasms in 1958, and since then it has been tried in prospective and retrospective studies for infantile spasms. Oral corticosteroids were also used in a few studies for infantile spasms. Variable success in cessation of infantile spasms and normalization of electroencephalograms was demonstrated. However, frequent significant adverse effects are associated with ACTH and oral corticosteroids. Vigabatrin has been used since the 1990s, and shown to be successful in resolution of infantile spasms, especially for infantile spasms associated with tuberous sclerosis. It is associated with visual field constriction, which is often asymptomatic and requires perimetric visual field study to identify. When ACTH, oral corticosteroids, and vigabatrin fail to induce cessation of infantile spasms, other alternative treatments include valproic acid, nitrazepam, pyridoxine, topiramate, zonisamide, lamotrigine, levetiracetam, felbamate, ganaxolone, liposteroid, thyrotropin-releasing hormone, intravenous immunoglobulin and a ketogenic diet. Rarely, infantile spasms in association with biotinidase deficiency, phenylketonuria, and pyridoxine-dependent seizures are successfully treated with biotin, a low phenylalanine diet, and pyridoxine, respectively. For medically intractable infantile spasms, some properly selected patients may have complete cessation of infantile spasms with appropriate surgical treatments.

The photopic negative response of the blue-on-yellow flash-electroretinogram in glaucomas and normal subjects

The photopic negative response of the flash-electroretinogram driven by the middle- and long-wavelength cones has been shown to be reduced in non-human primates with experimental glaucoma and in human patients with glaucoma. The photopic negative response for the blue-sensitive response has been studied using a blue-green silent-substitution-technique on a red background. The aim of this study was to re-evaluate the value of the photopic negative response of the blue-sensitive pathway in glaucoma using a conventional flash-electroretinogram. In 37 eyes of 37 controls (age: 53 +/- 13.6 years) and 37 eyes of 37 patients with open-angle glaucoma of different perimetric visual field defects (age: 58.3 +/- 10 years; MD: 11.7 +/- 6.7 dB) of the Erlangen glaucoma registry Ganzfeld flash-electroretinograms (LKC, UTAS 3000) were recorded using blue Xenon-flashes of increasing photopic luminance (0.013, 0.018, 0.030, and 0.052 cd s/m(2); 440 nm) on a bright yellow background (238 cd/m(2); 550 nm) after 2 min of light adaptation. Amplitudes and implicit times of the photopic negative response and of L&M-cone- and S-cone-driven b-waves were compared between glaucomas and controls for all flash energies (unpaired t-test). The amplitudes of the photopic negative response were significantly reduced in glaucoma patients for all flash energies (P < 0.001). The implicit times of L&M-cone-driven b-wave (0.013, 0.018, 0.030, and 0.052 cd s/m(2)) and S-cone-driven b-wave (0.030 and 0.052 cd s/m(2)) were significantly prolonged in glaucoma patients (P < 0.05). The changes in these implicit times, however, are very small (1.5 ms or less). The other measures did not differ significantly. The amplitude of the photopic negative response and the implicit times of the L&M-cone and S-cone b-wave in the same responses of the blue-on-yellow flash-electroretinogram are potentially useful in the evaluation of inner-retinal function in glaucoma.

Perimetric homonymous visual field loss post-stroke

Post-stroke homonymous visual field (PSHVF) loss has functional and driving implications for patients. Automated, as opposed to confrontational, assessment of PSHVF loss has the potential to provide a more reliable indicator for field loss and thus ability to drive. Sixty-one consecutive stroke admissions were assessed at 9 months post-stroke. Driving status and the patient’s awareness of any visual field loss was ascertained. Patients underwent formal perimetric visual field testing using a Humphrey Visual Field Analyser II. A separate, blinded, confrontational assessment of visual fields was made using the National Institutes of Health Stroke Scale (NIHSS) technique. Homonymous field defects were found in 10 (16%) patients, with 50% of these being hemianopia and 50% quadrantanopia. Right-sided field loss was more common (70%). No patients with PSHVF loss were aware of their loss, and only two were detected using NIHSS assessment. One patient was thought to have PSHVF loss on NIHSS assessment but this was not confirmed on perimetry. Of those with significant PSHVF loss at 9 months, 30% were driving. The prevalence of PSHVF loss is relatively high and is underestimated by confrontational testing. Stroke patients are often unaware of their field loss, with up to 5% driving with significantly affected visual fields at 9 months. Perimetric testing may be useful in decision-making regarding driving eligibility post-stroke.

Poster 28: Patterns of Training-Induced Recovery in Perimetric and Subjective Measures of Visual Field Size

Objectives: To compare perimetric and subjective visual field size and to observe their changes during vision restoration therapy (VRT) in patients with brain lesions. Design: Pre-post baseline comparison. Setting: Not provided. Participants: 19 patients with postgeniculate brain lesions. Intervention: Visual field measurement before and after 6 months of VRT. Main Outcome Measures: Visual field size as measured by high-resolution computer-based perimetry; subjective visual field size using standardized charts.

Perimetric visual field and functional MRI correlation: implications for image-guided surgery in occipital brain tumours

OBJECTIVETo compare the results of visual functional MRI with those of perimetric evaluation in patients with visual field defects and retrochiasmastic tumours and in normal subjects without visual field defect....

A risk-benefit assessment of treatments for infantile spasms.

Infantile spasms are a devastating epileptic encephalopathy of the young child. The continuing spasms and hypsarrhythmia have a deleterious effect on brain maturation and further cognitive development. Corticotropin (adrenocorticotropic hormone) or corticosteroids have been the gold standard treatment for the last 40 years, but there is little agreement on the best agent to use, or the dosage and duration of the treatment. Despite this empirical approach, corticotropin or corticosteroids are effective in controlling spasms and normalising electroencephalograms in about 60% of cases. The major concern with this treatment is the occurrence of frequent and severe adverse effects. The introduction of vigabatrin in the 1990s improved the outcome of infantile spasms. Vigabatrin shows an efficacy at least equal to that of corticosteroids, and even higher in specific groups such as those with tuberous sclerosis. The major advantages of vigabatrin are the ability to initiate treatment at the full dosage. rapid efficacy, suitability for outpatient treatment and particularly good tolerability with only minor adverse effects. Recently, however, the safety of vigabatrin has caused concern since a specific visual field loss has been reported in treated adults. The current problem is determining the risk-benefit ratio of vigabatrin and corticosteroids/corticotropin in children with infantile spasms, and to specify the groups where their use could be optimal. Visual field loss is usually asymptomatic and can be detected only by perimetric visual field studies. In children, especially in the young or disabled, it is difficult if not impossible to detect the visual field loss and it is not yet known if children are at higher or lower risk for this adverse effect. Until a clear answer about the occurrence of this adverse effect in children has been established through randomised study, vigabatrin may still be considered first-line therapy in infantile spasms. Children who do not achieve a good response to vigabatrin should be switched to corticotropin/corticosteroid therapy. Despite the efficacy of corticosteroids and vigabatrin, the use of the conventional antiepileptic drugs, the newly developed antiepileptic drugs and some promising results with ketogenic diet, 25 to 30% of patients with infantile spasms continue to have spasms and experience psychomotor regression. These drug-resistant patients could be candidates for surgery.