Pattern Of Visual Field Loss Research Articles

Bilateral Ocular Hypertension with Rapidly Progressive Optic Neuropathy in a Teen

We report a rare case of bilateral juvenile open-angle glaucoma (JOAG), with discussion of current understanding of its pathogenesis, differential diagnosis, genetics, and management. The importance of tonometry and dilated fundus examination as essential parts of a complete ocular examination, regardless of patient age, is emphasized. A Hispanic female teenager presented for an updated eye examination as a requirement before joining military boot camp. Chief concern was blurry vision at distance, with no other reported ocular or systemic problems. She manifested simple myopia in both eyes and was correctable to 20/20 in each eye with glasses. However, intraocular pressure (IOP) in each eye was measured above 40 mm Hg. Subsequent automated perimetry showed significant visual field defects, and laser polarimetry analysis of the optic nerve fibers corresponded with the visual field loss pattern. Maximal medical therapy was administered to lower the IOP, with minimal success. Subsequent incisional trabeculectomy with topical antimetabolite were performed in both eyes to achieve adequate control of her IOPs. Juvenile-onset Open Angle Glaucoma (JOAG) has been proposed to be a small subset of Primary Open Angle Glaucoma (POAG) and on a continual spectrum of Primary Open Angle Glaucoma. Because most patients with JOAG are asymptomatic, tonometry and optic nerve analysis are crucial in early detection and, thus, must be performed on all patients, young and old. JOAG has a variable onset, with rapidly progressive neuropathy that does not respond well to medical therapy alone, and surgical intervention is often the eventual treatment of choice. Mutations in the myocillin gene have been strongly linked to the disease. JOAG follows an autosomal dominant inheritance with relatively high penetrance. As such, close monitoring, genetics screening, and/or early medical management to prevent irreversible optic neuropathy and blindness should be considered as well for presymptomatic family members.

Loss of function mutations in the gene encoding latent transforming growth factor beta binding protein 2, LTBP2, cause primary congenital glaucoma

Glaucoma is a heterogeneous group of optic neuropathies that manifests by optic nerve head cupping or degeneration of the optic nerve, resulting in a specific pattern of visual field loss. Glaucoma leads to blindness if left untreated, and is considered the second leading cause of blindness worldwide. The subgroup primary congenital glaucoma (PCG) is characterized by an anatomical defect in the trabecular meshwork, and age at onset in the neonatal or infantile period. It is the most severe form of glaucoma. CYP1B1 was the first gene genetically linked to PCG, and CYP1B1 mutations are the cause of disease in 20-100% of patients in different populations. Here, we report that LTBP2 encoding latent transforming growth factor beta binding protein 2 is a PCG causing gene, confirming results recently reported. A disease-associated locus on chromosome 14 was identified by performing whole genome autozygosity mapping in Iranian PCG families using high density single nucleotide polymorphism chips, and two disease-segregating loss of function mutations in LTBP2, p.Ser472fsX3 and p.Tyr1793fsX55, were observed in two families while sequencing candidate genes in the locus. The p.Tyr1793fsX55 mutation affects an amino acid close to the C-terminal of the encoded protein. Subsequently, LTBP2 expression was shown in human eyes, including the trabecular meshwork and ciliary processes that are thought to be relevant to the etiology of PCG.

Endothelial dysfunction in glaucoma

Glaucoma is a group of ocular diseases characterized by optic neuropathy associated with loss of the retinal nerve fibre layer and re-modelling of the optic nerve head, and a subsequent particular pattern of visual field loss. Increased intraocular pressure is the most important risk factor for the disease, but the pathogenesis of glaucoma is not monofactorial. Among other factors, ischaemia and vascular dysregulation have been implicated in the mechanisms underlying glaucoma. The vascular endothelium plays an important role in the regulation of ocular blood flow and pathological alterations of vascular endothelial cells may induce ischaemia and dysregulation. The present review summarizes our current evidence of endothelial dysfunction in glaucoma. This is of interest because endothelial dysfunction is a good prognostic factor for progression in several diseases. Although such data are lacking for glaucoma, endothelial dysfunction may provide an attractive target for therapeutic intervention in open-angle glaucoma and other vascular disorders of the eye.

NATURAL COURSE OF VISUAL FIELD LOSS IN PATIENTS WITH TYPE 2 USHER SYNDROME

To evaluate the natural course of visual field loss in patients with Type 2 Usher syndrome and different patterns of visual field loss. Fifty-eight patients with Type 2 Usher syndrome who had at least three visual field measurements during a period of at least 3 years were studied. Kinetic visual fields measured on a standard calibrated Goldmann perimeter with II4e and V4e targets were analyzed. The visual field areas in both eyes were determined by planimetry with the use of a digitalizing tablet and computer software and expressed in square inches. The data for each visual field area measurement were transformed to a natural log unit. Using a mixed model regression analysis, values for the half-life of field loss (time during which half of the remaining field area is lost) were estimated. Three different patterns of visual field loss were identified, and the half-life time for each pattern of loss was calculated. Of the 58 patients, 11 were classified as having pattern type I, 12 with pattern type II, and 14 with pattern type III. Of 21 patients whose visual field loss was so advanced that they could not be classified, 15 showed only a small residual central field (Group A) and 6 showed a residual central field with a peripheral island (Group B). The average half-life times varied between 3.85 and 7.37 for the II4e test target and 4.59 to 6.42 for the V4e target. There was no statistically significant difference in the half-life times between the various patterns of field loss or for the test targets. The average half-life times for visual field loss in patients with Usher syndrome Type 2 were statistically similar among those patients with different patterns of visual field loss. These findings will be useful for counseling patients with Type 2 Usher syndrome as to their prognosis for anticipated visual field loss.

Glaucoma Detection With Frequency Doubling Perimetry and Short-wavelength Perimetry

The aim of this analysis was to evaluate the diagnostic usefulness of frequency doubling technology (FDT) perimetry and short-wavelength perimetry (SWAP). Moreover, to study a combination of both methods using the machine-learning technique double-bagging, which was recently established in glaucoma research. Forty-three patients with "preperimetric" open-angle glaucoma (glaucomatous optic disc atrophy and no visual field defect in standard perimetry), 26 patients with "perimetric" open angle glaucoma (glaucomatous optic disc atrophy and visual field defect in standard perimetry), and 40 control subjects had FDT screening (protocol: C-20-5) and SWAP (Octopus 101, G2). Criteria for exclusion were color vision abnormalities, media opacities, and an age below 31 years or above 63 years. Data of 1 eye of each patient and control subject entered the statistical evaluation. A point wise evaluation of the diagnostic power of SWAP values was performed to derive spatial patterns of visual field loss. A double-bagging machine-learning algorithm was used to train classification rules on the basis of a combination of FDT scores and nerve fiber related visual field losses in SWAP. The diagnostic power of the classifiers was compared regarding their misclassification error rates and area under the receiver-operating characteristic curve. The combination of FDT perimetry and SWAP yielded better diagnostic results compared with FDT or SWAP separately. The overall estimated misclassification error rate of the combined classifier was 24% compared with 28% for both SWAP and FDT perimetry. Regarding the estimated performance of classifier at high specificities (>80%) in control eyes as measured by the partial area under the receiver-operating characteristic curve, the combination of both instruments is also superior to the individual instruments. A combination of SWAP and FDT perimetry, each targeting different neuronal pathways, may improve early glaucoma detection.

Retinotopic organization of primary visual cortex in glaucoma: Comparing fMRI measurements of cortical function with visual field loss.

Primary open angle glaucoma (POAG) is a progressive optic neuropathy characterized by retinal ganglion cell loss. Experimental primate glaucoma indicates neuronal degeneration of the lateral geniculate nucleus (LGN) and activity changes in the visual cortex (V1). Neuronal degeneration has also been shown in a post-mortem human study of the optic nerve, LGN and visual cortex. Functional magnetic resonance imaging (fMRI), a non-invasive means of inferring function-specific neuronal activity, provides an opportunity to evaluate glaucomatous changes in neuronal activity throughout the visual pathway in vivo. The purpose of this study is to demonstrate that the relationship between visual field loss in human POAG and the functional organization of V1 can be measured using novel fMRI analysis methods. Visual field defects were measured using standard automated perimetry (SAP). A retinotopic map of visual space was obtained for V1, and the retinotopy data was fit with a template. The template was used to project regions within the visual field onto a flattened representation of V1. Viewing through the glaucomatous vs. fellow eye was compared by alternately presenting each eye with a scotoma-mapping stimulus. The resulting blood oxygen level dependent (BOLD) fMRI response was compared to interocular differences in thresholds for corresponding regions of the visual field. The spatial pattern of activity observed in the flattened representation agreed with the pattern of visual field loss. Furthermore, the amplitude of the BOLD response was correlated on a pointwise basis with the difference in sensitivity thresholds between the glaucomatous and fellow eyes (r = 0.53, p < 0.0001). The BOLD signal in human V1 is altered for POAG patients in a manner consistent with the loss of visual function. FMRI of visual brain areas is a potential means for quantifying glaucomatous changes in neuronal activity. This should enhance our understanding of glaucoma, and could lead to new diagnostic techniques and therapies.

Relative Risk of Progressive Glaucomatous Visual Field Loss in Patients Enrolled and Not Enrolled in a Prospective Longitudinal Study

To establish the relative risk of progressive visual field loss in a sample of glaucomatous eyes enrolled in a prospective longitudinal study vs a matched sample of eyes not enrolled in a study. The first visual field records of 66 glaucomatous eyes enrolled in a prospective longitudinal study (mean follow-up time, 3.4 years; mean number of visual field tests, 8.3) were matched to 66 eyes from patients not enrolled in a study (mean follow-up time, 3 years; mean number of visual field tests, 3.7). Eyes were matched on the basis of (1) time of enrollment, (2) length of follow-up, and (3) the extent and spatial pattern of visual field loss. Linear regression of global visual field indexes was used to measure change and the relative risk of progression was calculated for a series of progression criteria sample. The relative risk of progressive visual field loss was on average 368% (range, 209%-673%) higher in the eyes not enrolled in a prospective longitudinal study. Selection bias may reduce the risk of progressive visual field loss in patients enrolled in longitudinal studies.

Inter-Eye Comparison of Patterns of Visual Field Loss in Patients With Glaucomatous Optic Neuropathy

To compare inter-eye patterns of visual field (VF) loss on standard automated perimetry (SAP) in patients with glaucomatous optic neuropathy. Observational cross-sectional study. Four-hundred-and-ninety eyes of 245 patients with glaucomatous optic neuropathy in at least one eye defined by masked stereophoto review were included. Patients had two reliable SAP visual fields within fifteen months for each eye. Patterns of visual field loss were classified independently by two graders masked to all other patient information. Patterns were described as altitudinal, arcuate, partial arcuate, paracentral, nasal step, temporal wedge, or normal based on the classification system of Keltner and associates. Superior and inferior hemifields were graded separately. Inter-grader agreement in visual field patterns before adjudication was 97% and 94% for the worse eye (superior and inferior hemifield) and 97% and 95% for the better eye (superior and inferior hemifield). The percentage of correspondence by hemifield location was: 53% (superior-superior), 62% (inferior-inferior), 45% (superior-inferior), and 55% (inferior-superior). The highest correspondence of individual glaucomatous VF pattern between eyes was for arcuate (superior-superior) and inferior partial arcuate (inferior-inferior) defects (24% and 26%, respectively). Smaller hemifield patterns showed lower correspondence between the eyes (nasal step, paracentral, temporal wedge, 0% to 13% correspondence). Patterns of visual field loss between eyes often corresponded within the same VF hemifield (superior-superior, inferior-inferior) as well as between opposite hemifields (inferior-superior), although opposite hemifield correspondence was less common. More advanced visual field defects (for example, partial arcuate) showed higher correspondence rates between the eyes than less advanced defects.

Relationship Between Patterns of Visual Field Loss and Retinal Nerve Fiber Layer Thickness Measurements

To investigate the association between patterns of visual field (VF) loss and retinal nerve fiber layer (RNFL) thickness measurements. Observational cross-sectional study. One hundred twenty-one glaucoma patients and 65 healthy subjects from the Diagnostic Innovations in Glaucoma Study (DIGS) were included. All glaucoma patients had repeatable abnormal VFs and scanning laser polarimetry (SLP) RNFL thickness measurements. RNFL measurements were obtained from 16 equal parapapillary sectors. Patterns of VF loss were classified as arcuate, partial arcuate, nasal step, or paracentral in each VF hemifield. Logistic regression analysis was performed to determine which RNFL sectors were associated with each VF pattern. The ability of SLP to discriminate between eyes with different VF patterns and healthy eyes using receiver operating characteristic (ROC) curve analyses also was investigated. VF patterns in the superior hemifield were significantly associated with RNFL sectors in the temporal inferior hemiretina (P < .05). ROC curve areas for discrimination between eyes with different VF patterns and healthy eyes ranged from 0.85 to 0.95. VF patterns in the inferior hemifield were most strongly associated with temporal superior RNFL sectors (P < .05). ROC curve areas for discrimination between different VF patterns and healthy eyes ranged from 0.73 to 0.98. SLP could discriminate between apparently unaffected VF hemifields in glaucoma eyes and VF hemifields in healthy eyes. Parapapillary RNFL thickness was topographically related to patterns of VF loss. SLP can differentiate between apparently unaffected VF hemifields in glaucoma eyes and normal VF hemifields in healthy eyes.

Tissue Bioengineering

Glaucoma comprises a heterogeneous group of disorders, the final common pathways of which result in the death of retinal ganglion cells (RGC) and subsequent characteristic patterns of visual field loss and excavation of the optic nerve head. Those glaucomas in which elevated intraocular pressure (IOP) predominate are characterized by dysfunction of the trabecular meshwork, resulting in increased resistance to aqueous outflow. Non-pressure-dependent mechanisms remain poorly delineated and may consist of cardiovascular and local ischemic conditions, autoimmune and connective tissue disorders, and genetic predisposition to retinal ganglion cell death.

Neurological eye problems

Abstract This review of important neuro-opthalmalogical conditions covers ocular vascular disorders, optic neuropathies, the causes of optic disc swelling, patterns of visual field loss and opthalmoplegia. Critical features in the history and examination are highlighted, and management discussed.

Using unsupervised learning with variational bayesian mixture of factor analysis to identify patterns of glaucomatous visual field defects.

To determine whether an unsupervised machine learning classifier can identify patterns of visual field loss in standard visual fields consistent with typical patterns learned by decades of human experience. Standard perimetry thresholds for 52 locations plus age from one eye of each of 156 patients with glaucomatous optic neuropathy (GON) and 189 eyes of healthy subjects were clustered with an unsupervised machine classifier, variational Bayesian mixture of factor analysis (vbMFA). The vbMFA formed five distinct clusters. Cluster 5 held 186 of 189 fields from normal eyes plus 46 from eyes with GON. These fields were then judged within normal limits by several traditional methods. Each of the other four clusters could be described by the pattern of loss found within it. Cluster 1 (71 GON + 3 normal optic discs) included early, localized defects. A purely diffuse component was rare. Cluster 2 (26 GON) exhibited primarily deep superior hemifield defects, and cluster 3 (10 GON) held deep inferior hemifield defects only or in combination with lesser superior field defects. Cluster 4 (6 GON) showed deep defects in both hemifields. In other words, visual fields within a given cluster had similar patterns of loss that differed from the predominant pattern found in other clusters. The classifier separated the data based solely on the patterns of loss within the fields, without being guided by the diagnosis, placing 98.4% of the healthy eyes within the same cluster and spreading 70.5% of the eyes with GON across the other four clusters, in good agreement with a glaucoma expert and pattern standard deviation. Without training-based diagnosis (unsupervised learning), the vbMFA identified four important patterns of field loss in eyes with GON in a manner consistent with years of clinical experience.

The spectrum of human rhodopsin disease mutations through the lens of interspecific variation*1

Mutations in rhodopsin, the visual pigment found in rod cells, account for a large fraction of genetic changes underlying the human retinal diseases, Retinitis Pigmentosa (RP). The availability of rhodopsin sequences from a large number of vertebrates has allowed us to investigate factors important in the development of RP by contrasting interspecific differences (long-term evolutionary patterns) with RP disease mutation data. We find that disease mutations in rhodopsin are overabundant in highly conserved sites and that amino acid positions with any potential of variability among vertebrates are likely to harbour disease mutations less frequently. At any amino acid position in rhodopsin, the set of disease-associated amino acids does not show any commonality with the set of amino acids present among species. The disease mutations are biochemically four times more radical than the interspecific (neutral) variation. This pattern is also observed when disease mutations are categorized based on clinical classifications that reflect biochemical, physiological and psychophysical traits such as protein folding, cone electroretinogram (ERG) amplitude, pattern of visual field loss, and equivalent field diameter. We also found that for artificial mutations (those not observed in nature interspecifically), there was a positive relationship between the biochemical distance and the magnitude of blue shift in the absorption spectrum maximum. We introduce the concept of the expected chemical severity based on the normal human codon at a position. Results reveal that the analysis of disease mutations in the context of the original codon is very important for the practical application of evolutionary principles when comparing original and disease amino acid mutations. We conclude that the analysis of rhodopsin data clearly demonstrates the usefulness of molecular evolutionary analyses for understanding patterns of clinical as well as artificial mutations and underscores the biomedical insights that can be gained by using simple measures of biochemical difference in the context of evolutionary divergence.

The spectrum of human rhodopsin disease mutations through the lens of interspecific variation

Mutations in rhodopsin, the visual pigment found in rod cells, account for a large fraction of genetic changes underlying the human retinal diseases, Retinitis Pigmentosa (RP). The availability of rhodopsin sequences from a large number of vertebrates has allowed us to investigate factors important in the development of RP by contrasting interspecific differences (long-term evolutionary patterns) with RP disease mutation data. We find that disease mutations in rhodopsin are overabundant in highly conserved sites and that amino acid positions with any potential of variability among vertebrates are likely to harbour disease mutations less frequently. At any amino acid position in rhodopsin, the set of disease-associated amino acids does not show any commonality with the set of amino acids present among species. The disease mutations are biochemically four times more radical than the interspecific (neutral) variation. This pattern is also observed when disease mutations are categorized based on clinical classifications that reflect biochemical, physiological and psychophysical traits such as protein folding, cone electroretinogram (ERG) amplitude, pattern of visual field loss, and equivalent field diameter. We also found that for artificial mutations (those not observed in nature interspecifically), there was a positive relationship between the biochemical distance and the magnitude of blue shift in the absorption spectrum maximum. We introduce the concept of the expected chemical severity based on the normal human codon at a position. Results reveal that the analysis of disease mutations in the context of the original codon is very important for the practical application of evolutionary principles when comparing original and disease amino acid mutations. We conclude that the analysis of rhodopsin data clearly demonstrates the usefulness of molecular evolutionary analyses for understanding patterns of clinical as well as artificial mutations and underscores the biomedical insights that can be gained by using simple measures of biochemical difference in the context of evolutionary divergence.

Medically unexplained visual loss in adult patients.

To evaluate the characteristics of patients with nonorganic or medically unexplained visual loss (MUVL) presenting to a neuro-ophthalmology clinic. A retrospective review of the case notes of patients identified from our diagnostic register. All patients had been followed up for at least 18 months and investigations (including, in all cases, neuroimaging) had failed to reveal any underlying pathology. To be included, patients had to have at least one inconsistent feature on visual function testing. : We identified 58 patients with MUVL. A total of 79% of patients were female and 21% were male. In total, 36% of patients had been seen in other medical specialties with unexplained symptoms. In all, 60% of patients complained of glare or pain. Of the patients with bilateral visual loss, the acuities were frequently the same in each eye and the most common pattern of visual field loss was concentric contraction. Those with unilateral visual loss had a more variable pattern of visual failure. In total, 22% of patients showed some visual recovery though this was usually incomplete. In one patient, organic pathology accounting for the visual symptoms became apparent after the end of the 18 month follow-up period. Medically unexplained symptoms, in general, form an important part of the workload in most medical specialties. Unexplained symptoms in ophthalmology have not been well studied. Terminology should be brought into line with that used in other medical specialties. Further work may help in the identification of positive diagnostic features of MUVL which should not be simply a 'diagnosis of exclusion'.

Optineurin in primary open angle glaucoma.

The authors' initial estimate indicated that mutations in Optineurin are responsible for a significant proportion of LPG/POAG families. Currently, there are up to 1.2 million persons with LPG and up to 2.47 million persons with POAG in the United States alone. Perhaps twice as many individuals are already affected with this condition without any identifiable clinical signs or symptoms. Investigators are eagerly awaiting confirmation of OPTN mutations in other glaucoma populations. Although additional mutations have already been identified in the sporadic cases of LPG, the significance of this gene in high-pressure POAG requires more intensive investigation. Limited data on partial screening of this gene indicate that OPTN mutations are responsible for a limited number of cases of high-pressure POAG. If the reported mutation rates of OPTN in the LPG group can be confirmed in other LPG or POAG patients, then this gene would be useful in diagnosing presymptomatic persons many decades before they develop this silent and blinding eye condition. Early identification of such at-risk patients would provide an opportunity for immediate targeted medical treatments and specific glaucoma therapy that might significantly delay or completely stop the gradual progression of this condition. Therefore, identification of glaucoma-causing genes such as Myocilin, Optineurin, and others could provide molecular diagnostic tools for this category of optic neuropathy. Although patients with advanced glaucoma will not directly benefit from the use of such molecular diagnostic tools, their immediate family members could certainly benefit from the identification of the cause of the glaucoma decades before the first manifestation of the disease. In summary, a series of mutations in the Optineurin gene have been shown to be the principal cause of adult-onset LPG/POAG phenotype in certain pedigrees. The exact mechanisms through which these mutations lead to the development of glaucoma require additional functional study. The existing evidence suggests that direct interaction of Optineurin with E3-14.7K protein probably utilizes TNF-alpha or Fas-ligand pathways to mediate apoptosis, inflammation, or vasoconstriction. Optineurin also functions through its interactions with other proteins in cellular morphogenesis and membrane trafficking (RAB8), vesicle trafficking (Huntingtin), transcription activation (TFIIIA), and assembly or activity of two unknown kinases. Identification of Optineurin as an adult-onset glaucoma gene and its known interaction with a group of proteins provides the first opportunity to study biochemical pathways that are thought to be involved in causation of this group of eye disorders. Furthermore, identification of this gene as a contributing factor to the development of glaucoma gives a useful tool for screening of this disorder in the elderly population and other high-risk individuals. The exact impact of OPTN in the development of all glaucoma phenotypes requires future study.

Examining visual field defects in the paediatric population exposed to vigabatrin.

The antiepileptic drug, vigabatrin, has been linked to a specific pattern of visual field loss. The majority of studies have not included the paediatric population due to difficulties assessing visual field function. This is a particular problem as vigabatrin is effective against infantile spasms. A field-specific visual evoked potential was developed which consisted of a central stimulus (0-5 degrees radius) and a peripheral stimulus (30-60 degrees radius). Both stimuli consist of black and white checks which increase in size with eccentricity. Responses are recorded from occipital electrodes O2 and O1 referred to frontal electrode Fz. Electroretinograms and perimetry was performed were possible as a comparison. Thirty-nine children with epilepsy treated with vigabatrin aged from 3 to 15 years were included in the study; 35/39 children complied with the field-specific VEP, 26/39 complied with the ERG and 11/39 performed perimetry. Of these results, 18 children had normal ERG responses and eight had abnormal response. Visual field testing revealed four children had abnormal and seven had abnormal visual field results. The Field-specific VEP identified three of four abnormal perimetry results and six of seven normal perimetry results, giving a sensitivity of 75% and a specificity of 85.7%. When comparing perimetry results with the ERG parameters only the 30-Hz flicker amplitude, with a cut-off amplitude below 70 microV, gave a useful sensitivity of 75% and a specificity of 71%. The field-specific VEP is a useful alternative method that is both well tolerated by young children and gives a reliable indication of likely peripheral visual field loss associated with vigabatrin. The defect appears to have a similar prevalence in children as it does in adults.

Optic neuritis: Correlation of pain and magnetic resonance imaging

Purpose To demonstrate whether the magnetic resonance imaging (MRI) localization of the abnormal enhancement of the optic nerve can be related to the pain or pattern of visual field loss associated with acute optic neuritis. Design Retrospective observational series and MRI review from a referral neuro-ophthalmology service. Participants Seventy-three women and 23 men with acute optic neuritis who had high resolution gadolinium-enhanced fat-suppressed MRI within twenty days of the onset of visual loss. Methods The presence of eye or other fifth cranial nerve (V 1) pain, and pain with eye movement ipsilateral to the affected optic nerve or no eye pain was recorded. The neuroradiologist reviewed the MRI, masked to the affected eye, and recorded the length and segment (orbital, canalicular, intracranial, or combination of segments) of abnormal optic nerve enhancement. The presenting visual field defects were characterized as diffuse, central, arcuate, nasal or temporal. Main outcome measures The types of pain and patterns of field loss were correlated with the segments of optic nerve enhancement in the affected eye. Results Five patients had nerves that did not enhance and were excluded from the outcome analysis. In the 91 patients with abnormal enhancement, 70 experienced eye/V 1 pain, 67 had pain with eye movement and 17 patients had no pain. Enhancement of the orbital optic nerve occurred in 66 patients, 93.9% who had eye/V 1 pain and 92.4% who had pain with eye movement. In the 25 patients with enhancement of the canalicular, intracranial or both segments, without orbital involvement, 32% had eye/V 1 pain and 24% had pain with eye movement. No pain occurred in 3% with enhancement of the orbital segment and in 60% with enhancement of the other optic nerve segments. The length of enhancement moderately correlated with eye/V 1 pain ( r = 0.49, P = 0.01) and pain with eye movement ( r = 0.37, P = 0.01). Patients with enhancement longer than 10 mm had pain five times ( P = 0.004) more frequent than did those with enhancement ≤10 mm. There was no significant specific pattern of field loss associated with a particular location of enhancement, except temporal field loss occurred in 25% of intracranial lesions ( P = 0.04). Conclusion When optic neuritis involved the orbital segment of the optic nerve, eye or other V 1 distribution pain (94.3% vs. 32%) and pain with eye movement (91.4% vs. 24%) were significantly more frequent. In contrast, pain was absent 20 times more often when the orbital segment was not involved (60% vs. 3%). Except for temporal field loss in eyes with intracranial nerve lesions, no pattern of visual field loss appeared to correlate with the location or length of abnormal optic nerve enhancement.

Patterns of glaucomatous visual field defects in an older population: the Blue Mountains Eye Study.

This report aims to describe the frequency of different patterns of visual field loss in open-angle glaucoma (OAG). The Blue Mountains Eye Study examined 3654 persons (aged 49+) during 1992-1994. Humphrey supra-threshold visual fields were performed in 88.9%. Those classified as glaucoma suspects had 30-2 full-threshold fields (9.2%). Of OAG cases (n = 108) with field tests in both eyes (n = 97), unilateral defects were present in 49 (50.5%) and bilateral in 48 (49.5%). Advanced field loss was found in 16 (15.4%) subjects and in 22 (10.9%) eyes, with bilateral loss present in 6 (6.2%) cases. Of all eyes of OAG cases (n = 201), 49 (24.4%) had no defects, 52 (25.9%) upper, 61 (30.3%) lower, and 17 (8.5%) had combined upper and lower loss. Of the upper and lower cases (n = 113), the types of defects included nasal step (36), arcuate (26), nasal plus arcuate (26), and hemispherical defects (25). Of subjects with fields in at least one eye (n = 104), there was a similar proportion in the worse eye of upper defects (28.8%), lower (31.7%), and combined upper and lower (24.0%). Undiagnosed OAG was more frequent in unilateral (65.3%) than bilateral (34.7%) cases (P = 0.003). This study reports the pattern of typical glaucomatous field loss in an older Australian population.

Field-specific visual evoked potentials. Identifying field defects in vigabatrin-treated children. Harding GFA, Spencer EL, Wild JM, Conway M, Bohn RL. Neurosurgery 2002;58:1261–1265.

Previous studies have linked vigabatrin, an antiepileptic drug, to a specific pattern of visual field loss from retinal toxicity. The visual field defect typically consists of bilateral concentric constriction with a binasal annular defect within the central 30 degrees and relative temporal sparing. Few studies have included the pediatric population because of difficulties in assessing the visual field by perimetry earlier than the age of 9 years, despite the fact that several of the most important indications for the use of vigabatrin are in children. A field-specific visual-evoked potential (VEP) was designed to identify visual field defects in children with epilepsy treated with vigabatrin, especially those unable to perform perimetry. This VEP was created with central (0–5-degree radius) and peripheral (30–60-degree radius) stimuli. Stimuli consisted of black-and-white checks that increased in size with eccentricity. Checks reversed at different rates, allowing separate central and peripheral responses to be recorded. Five vigabatrin-treated young adults with field defects were identified using this stimulus. Electroretinograms (ERG) were recorded to examine the effects of vigabatrin on retinal function. Thirty-nine children aged 3 to 15 years were included in the study. Twelve patients were examined by both the field-specific stimulus test and perimetry. Thirty-five of 39 children complied with the field-specific stimulus, 26 of 39 complied with the ERG, and 12 of 39 complied with perimetry. Using the summed amplitude of the peripheral response from O2 and O1, responses below 10 μV were deemed abnormal. The field-specific stimulus identified three of four abnormal perimetry results and seven of eight normal perimetry results, giving a sensitivity of 75% and a specificity of 87.5%. When comparing perimetry results with the ERG parameters, only the 30-Hz flicker amplitude, with a cutoff below 70 μV, gave a useful indication of visual field loss. The authors conclude that field-specific VEPs are well tolerated by children older than 2 years of age and are sensitive and specific in identifying vigabatrin-associated peripheral field defects.—Nancy J. Newman