Development Of Visual Field Defects Research Articles

Malignant transformation of meningioma: Case report.

Meningiomas are mostly benign brain tumors with minimal malignant cases. Anaplastic meningioma has malignant morphological characteristics and a World Health Organization grade of III. The present study reports a case of an occipital meningioma in a patient who initially chose observation and follow-up after diagnosis. The patient ultimately underwent surgery due to the enlargement of the tumor and the development of visual field defects after a decade of imaging follow-up. The postoperative pathology slides indicated the presence of an anaplastic meningioma (World Health Organization-grade III). The patient's diagnosis was established through cranial magnetic resonance imaging, which revealed an irregular mixed mass in the right occipital region with isointense T1 and hypointense T2 signal, irregular lobulation, and a maximum diameter of approximately 5.4 cm. Heterogenous enhancement was observed in the contrast-enhanced scan. The patient opted for surgical intervention to remove the tumor, and the pathology slides of the tumor sample confirmed the diagnosis of anaplastic meningioma. The patient also received radiotherapy (40Gy/15fr). No recurrence was observed during the 9-month follow-up. This case highlights the potential for low-grade meningiomas to undergo malignant transformation, particularly in the presence of irregular lobulation, peritumoral brain edema, and heterogeneous enhancement on contrast-enhanced scans. Total excision (Simpson grade I) is the preferred treatment option, and long-term imaging follow-up is recommended.

Structural changes in retina (Retinal nerve fiber layer) following mild traumatic brain injury and its association with development of visual field defects

BackgroundMild traumatic brain injury (mTBI)is the most common form of traumatic brain injury accounting for 70–80% of all brain injuries annually. There is increasing evidence that long lasting morphological and functional consequence can be present in visual system following mTBI. Among all the visual manifestation, awareness of Visual field defects is important because it may compromise the social, personal or professional life of any individual. Retinal structural changes such as thinning of Retinal nerve fiber layer (RFNL)captured using optical coherence tomography have emerged as a possible biomarker in many neurological diseases however very little is known in cases with mTBI Objective(I) To demonstrate the structural changes/morphological changes in retina if any following mTBI. (II) Whether the structural changes in retina have any association with the development of Visual field deficits leading to Visual function impairment following mTBI (III) Clinical relevance of structural changes in retina as a possible biomarker for visual function impairment due to visual field deficits. Materials and MethodsOur study included 60 patients with mTBI who fulfilled the inclusion criteria. All patients underwent a detailed ophthalmic evaluation with special focus on temporal recording of Retinal nerve layer thickness using SD- Optical Coherence Tomography and Visual field (Visual field Index) by Humphrey Automated Field Analyser. Results30% of eyes had significant thinning of RFNL (> 30% of the base line thickness) at 6 months following mTBI. Visual function impairment due to visual field deficits (VFI < 80%) at 6 months was seen in 40% of the eyes. The structural changes and visual function impairment peaked at 6 months’ post injury. A strong Association was noted between RFNL thinning and manifestation of Visual field deficits (VFI < 80%) leading to visual function impairment (P < 0.001). The Correlation Co-efficient between thinning of RFNL and Visual field deficits had a positive correlation(p < 0.001). ConclusionThis novel study has demonstrated that visual functional impairment due to Visual field deficits is a real possibility following mTBI. Monitoring of retinal parameter such as thinning of Retinal nerve fiber layer, using Optical coherence tomography, can be a biomarker for early detection or development of visual field defects in mTBI.

Structure/function/treatment in glaucoma: progress over the last 10years

Since the 1990s several so-called landmark studies were carried out, which played an important role in the management of glaucoma patients due to their multicenter, randomized and masked structure. The Ocular Hypertension Treatment Study (OHTS) and the Collaborative Initial Treatment Glaucoma Study (CIGTS) and their follow-up studies are especially important in the conservative glaucoma management and in the evaluation of structure and function. The OHTS examined if lowering of the intraocular pressure (IOP) treatment reduces the progression from ocular hypertension to primary open angle glaucoma and what risk factors influence the progression. The CIGTS examined the progression of glaucoma in patients treated either with pharmacotherapy or with surgery. The recent studies, the United Kingdom Glaucoma Treatment Study (UKGTS) and Glaucoma Automated Test Evaluation (GATE) investigated the influence of treatment with latanoprost on the development of visual field defects and examination of different screening tests in glaucoma, respectively. The OHTS provided results that justify prophylactic treatment as well as watchful waiting. The results of CIGTS showed that under certain conditions surgical treatment of a newly discovered glaucoma can be recommended for moderate to advanced glaucoma. In the UKGTS treatment with latanoprost reduced the intraocular pressure and also the progression of visual field defects in beginning and moderate glaucoma damage. The GATE study found no clear-cut advantage of screening examinations, with cost effectiveness and without a substantial proportion of diagnoses being missed.

Predicting Glaucoma Development With Longitudinal Deep Learning Predictions From Fundus Photographs

To assess whether longitudinal changes in a deep learning algorithm's predictions of retinal nerve fiber layer (RNFL) thickness based on fundus photographs can predict future development of glaucomatous visual field defects. Retrospective cohort study. This study included 1,072 eyes of 827 glaucoma-suspect patients with an average follow-up of 5.9 ± 3.8 years. All eyes had normal standard automated perimetry (SAP) at baseline. Additional SAP and fundus photographs were acquired throughout follow-up. Conversion to glaucoma was defined as repeatable glaucomatous defects on SAP. An OCT-trained deep learning algorithm (machine to machine, M2M) was used to predict RNFL thicknesses from fundus photographs. Joint longitudinal survival models were used to assess whether baseline and longitudinal change in M2M's RNFL thickness estimates could predict development of visual field defects. A total of 196 eyes (18%) converted to glaucoma during follow-up. The mean rate of change in M2M's predicted RNFL thickness was -1.02μm/y for converters and -0.67μm/y for non-converters (P < .001). Baseline and rate of change of predicted RNFL thickness were significantly predictive of conversion to glaucoma, with hazard ratios in the multivariable model of 1.56 per 10μm lower at baseline (95% CI, 1.33-1.82; P < .001) and 1.99 per 1μm/y faster loss in thickness during follow-up (95% CI, 1.36-2.93; P < .001). Longitudinal changes in a deep learning algorithm's predictions of RNFL thickness measurements based on fundus photographs can be used to predict risk of glaucoma conversion in eyes suspected of having the disease.

Retinal nerve fibre layer thickness measured by spectral domain optical coherence tomography amongst early primary open-angle glaucoma patients at Hospital Melaka

Introduction: Glaucoma is second only to cataract as a cause of blindness worldwide and Asians account for almost half the cases. Retinal nerve fibre layer (RNFL) assessment is an important objective method for diagnosis and monitoring of glaucoma as it develops earlier than the development of visual field defects.&#x0D; Purpose: To estimate the proportion of primary open-angle glaucoma (POAG) patients with normal RNFL thickness (RNFLT) amongst early POAG patients who were under follow-up at the Ophthalmology Department, Hospital Melaka (Melaka, Malaysia).&#x0D; Study design: Observational cross-sectional study.&#x0D; Materials and methods: Consecutive sampling of 64 POAG patients who were diagnosed as early POAG as defined by the Glaucoma Staging System 2 (GSS 2) into stage 1 and 2 on Octopus visual field test were recruited in this study. Data collected included demographic data, refraction, slit-lamp examination, intraocular pressure (IOP), gonioscopy, peripapillary retinal nerve fibre layer thickness (RNFLT) measured by spectral-domain optical coherence tomography (SD-OCT), and fundus photography.&#x0D; Results: Among 64 eyes, 57.8% were found to have normal and 42.2% to have abnormal RNFLT classification. There was no difference in terms of age, gender or ethnicity between those with normal and abnormal RNFLT. Mean IOP at presentation, mean duration of POAG, and mean spherical dioptres were compared between the two groups. Only mean spherical dioptres showed a significant difference between the two groups, p &lt; 0.001. An increase of spherical dioptres also had a moderate positive correlation with RNFLT in most optic disc quadrants except the nasal, temporal, superonasal, and inferonasal quadrants.&#x0D; Conclusion: OCT cannot be used as a diagnostic tool alone, especially in early glaucoma, as it showed a normal RNFLT in almost half the patients. RNFLT in early POAG had significant correlation with spherical dioptres in most quadrants.

Vigabatrin add-on therapy for drug-resistant focal epilepsy.

This is an updated version of the original Cochrane Review published in 2008 and updated in 2013. Epilepsy is a common neurological condition which affects up to 1% of the population. Approximately 30% of people with epilepsy do not respond to treatment with currently available drugs. The majority of these people have focal epilepsy. Vigabatrin is an antiepileptic drug licensed for use in drug-resistant epilepsy. To assess the efficacy and tolerability of vigabatrin as an add-on therapy for people with drug-resistant focal epilepsy. For the latest update of this review, we searched the following databases on 1 November 2018: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid 1946 to 31 October 2018), ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform. The Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL) are both included in the Cochrane Register of Studies (CRS Web). We checked reference lists of retrieved studies for additional reports of relevant studies and contacted Hoechst Marion Roussel (manufacturers of vigabatrin) in 2000. We included randomised, double-blind, placebo-controlled, fully published trials of vigabatrin in people of any age with drug-resistant focal epilepsy. Two review authors assessed trials for inclusion and extracted data using the standard methodological procedures expected by Cochrane. Primary analysis was by intention-to-treat (ITT). We evaluated: 50% or greater reduction in seizure frequency, treatment withdrawal, adverse effects, dose-response analysis, cognitive outcomes and quality of life. We presented results as risk ratios (RR) with 95% or 99% confidence intervals (CI). We identified 11 trials that included 756 participants (age range: 10 to 64 years). The trials tested vigabatrin doses between 1 g/day and 6 g/day. All 11 trials displayed a risk of bias across at least three risk of bias domains. Predominantly, the risk of bias was associated with: allocation concealment (selection bias), blinding of outcome assessment (detection bias) and incomplete outcome data (attrition bias). Participants treated with vigabatrin may be two to three times more likely to obtain a 50% or greater reduction in seizure frequency compared with those treated with placebo (RR 2.60, 95% CI 1.87 to 3.63; 4 studies; low-certainty evidence). Those treated with vigabatrin may also be three times more likely to have treatment withdrawn although we are uncertain (RR 2.86, 95% CI 1.25 to 6.55; 4 studies; very low-certainty evidence). Compared to placebo, participants given vigabatrin were more likely to experience adverse effects: dizziness/light-headedness (RR 1.74, 95% CI 1.05 to 2.87; 9 studies; low-certainty evidence), fatigue (RR 1.65, 95% CI 1.08 to 2.51; 9 studies; low-certainty evidence), drowsiness (RR 1.70, 95% CI 1.18 to 2.44; 8 studies) and depression (RR 3.28, 95% CI 1.30 to 8.27; 6 studies). Although the incidence rates were higher among participants receiving vigabatrin compared to those receiving placebo, the effect was not significant for the following adverse effects: ataxia (RR 2.76, 95% CI 0.96 to 7.94; 7 studies; very low-certainty evidence), nausea (RR 3.57, 95% CI 0.63 to 20.30; 4 studies), abnormal vision (RR 1.64, 95% CI 0.67 to 4.02; 5 studies; very low-certainty evidence), headache (RR 1.23, 95% CI 0.79 to 1.92; 9 studies), diplopia (RR 1.76, 99% CI 0.94 to 3.30) and nystagmus (RR 1.53, 99% CI 0.62 to 3.76; 2 studies; low-certainty evidence). Vigabatrin had little to no effect on cognitive outcomes or quality of life. Vigabatrin may significantly reduce seizure frequency in people with drug-resistant focal epilepsy. The results largely apply to adults and should not be extrapolated to children under 10 years old. Short-term follow-up of participants showed that some adverse effects were associated with its use. Analysis of longer-term observational studies elsewhere, however, has demonstrated that vigabatrin use can lead to the development of visual field defects.

Ganglion Cell-Inner Plexiform Layer and Retinal Nerve Fiber Layer Changes in Glaucoma Suspects Enable Prediction of Glaucoma Development

To investigate whether progressive macular ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thinning predict development of visual field (VF) defects in glaucoma suspects. Retrospective cohort study. This study included 541 eyes of 357 glaucoma suspects with a mean follow-up of 5.7 years. Progressive GCIPL and RNFL thinning were determined using Guided Progression Analysis (GPA) in optical coherence tomography (OCT). The development of VF defect was defined as the presence of three consecutive abnormal VFs. The risk of developing VF defect was evaluated using Cox proportional hazard models. A total of 74 eyes (13.7%) and 87 eyes (16.1%) showed progressive GCIPL and RNFL thinning by OCT GPA, respectively, and 40 eyes (7.4%) developed VF defects. Eyes with progressive GCIPL (hazard ratio [HR], 7.130; 95% confidence interval [CI], 3.137-16.205) and RNFL (HR, 7.525; 95% CI, 3.272-17.311) thinning showed a significantly higher risk of developing VF defects. The rate of change in the average GCIPL and RNFL thickness was significantly higher in the eyes that developed VF defects (-0.71 and-1.13μm/y, respectively) than the eyes that did not (-0.19 and-0.27 μm/y, respectively; all P < 0.05). Progressive GCIPL (43.1 vs. 63.1 months, respectively; P < 0.001) and RNFL (50.9 vs. 66.7months, respectively; P < 0.001) thinning were detected significantly earlier than the development of VF defects. Monitoring progressive change in GCIPL, as well as RNFL, effectively predicts the development of VF defects in glaucoma suspects.

Management of nonfunctioning pituitary adenomas (NFAs): observation.

Clinically nonfunctioning pituitary adenomas (NFAs) range from those causing significant hypothalamic/pituitary dysfunction and visual field compromise due to their large size to those being completely asymptomatic. In the absence of hypersecretion, hypopituitarism or visual field defects, patients with NFAs may be followed by periodic surveillance using MRI to detect tumor enlargement. In some cases, endocrine tests are also needed during observation to discover new pituitary dysfunction. Enlargement of NFAs without treatment occurs in about 10% of microadenomas and 23% of macroadenomas. Growth of a pituitary incidentaloma, the development of visual field defects or the development of hypopituitarism are potential indications for surgery during follow up.

Development of visual field defect after first-detected optic disc hemorrhage in preperimetric open-angle glaucoma.

To evaluate functional progression in preperimetric glaucoma (PPG) with disc hemorrhage (DH) and to determine the time interval between the first-detected DH and development of glaucomatous visual field (VF) defect. A total of 87 patients who had been first diagnosed with PPG were enrolled. The medical records of PPG patients without DH (Group 1) and with DH (Group 2) were reviewed. When glaucomatous VF defect appeared, the time interval from the diagnosis of PPG to the development of VF defect was calculated and compared between the two groups. In group 2, the time intervals from the first-detected DH to VF defect of the single- and recurrent-DH were compared. Of the enrolled patients, 45 had DH in the preperimetric stage. The median time interval from the diagnosis of PPG to the development of VF defect was 73.3months in Group 1, versus 45.4months in Group 2 (P=0.042). The cumulative probability of development of VF defect after diagnosis of PPG was significantly greater in Group 2 than in Group 1. The median time interval from first-detected DH to the development of VF defect was 37.8months. The median time interval from DH to VF defect and cumulative probability of VF defect after DH did not show a statistical difference between single and recurrent-DH patients. The median time interval between the diagnosis of PPG and the development of VF defect was significantly shorter in PPG with DH. The VF defect appeared 37.8months after the first-detected DH in PPG.

Confocal Laser Scanning Tomography to Predict Visual Field Conversion in Patients With Ocular Hypertension and Early Glaucoma.

To compare Moorfields regression analysis (MRA), Glaucoma probability score (GPS), and different discriminant functions to predict future visual field conversion of patients with ocular hypertension and early glaucoma. The study included 120 eyes of patients with ocular hypertension and 110 eyes of patients with early glaucoma from the Erlangen glaucoma registry. Annually, all patients underwent standard automated perimetry, 24-hour intraocular pressure profile, optic disc photography, and HRT (Heidelberg Retina Tomograph I-III; Heidelberg Engineering) measurements. The cohort was divided into 2 groups based on the development of repeatable glaucomatous visual fields. Positive predictive values and negative predictive values were compared for MRA, GPS, and the classification of Bathija, Iester, Mardin, and Mikelberg at baseline. Kaplan-Meier Survival curves and Logrank tests were used to evaluate equality of survival distributions for different test results. Median follow-up was 9.04 years. 26 eyes (11.3%) demonstrated glaucomatous visual field loss in the follow-up. MRA temporal-superior and temporal-inferior outside normal limits were predictive of future visual field loss with positive predictive values of 33.3% and 28.6%. Normal GPS Temporal Sector demonstrated a negative predictive value of 96.4% and normal results in discriminant functions between 94.7% and 95.5%. Confocal scanning laser tomography is a useful imaging modality to predict future visual field conversion. Development of visual field defects in 10 years is highly unlikely, if GPS classification and/or classification of discriminant analysis at baseline are normal. MRA temporal-superior and temporal-inferior outside normal limits are associated with future VF conversion (ClinicalTrials.gov number, NCT00494923).

Vigabatrin versus carbamazepine monotherapy for epilepsy.

This is an update of a Cochrane review first published in 2012 (Cochrane Database of Systematic Reviews 2012, Issue 1).The efficacy and safety of vigabatrin (VGB) as an add-on therapy for refractory epilepsy have been well established. However, this information needs to be weighed against the risk of development of visual field defects. Whether VGB monotherapy is an effective and safe treatment compared with the standard antiepileptic drug carbamazepine (CBZ) as monotherapy for epilepsy has not been systematically reviewed. To investigate the efficacy and safety of VGB versus CBZ monotherapy for epilepsy in children and adults. For the latest update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 3 of 4), MEDLINE (1948 to July 2015), EMBASE (1974 to July 2015) and the Chinese Biomedical Database (CBM) (1979 to July 2015). We searched trial registers and contacted themanufacturer of VGB and authors of included studies for additional information. We applied no language restrictions. Randomised controlled trials (RCTs) comparing VGB versus CBZ monotherapy for epilepsy. Two review authors independently assessed trial quality and extracted data. The primary outcome was time to treatment withdrawal. Secondary outcomes were time to achieve six-month and 12-month remission after randomisation, time to first seizure after randomisation and adverse events. We presented results as hazard ratios (HRs) with 95% confidence intervals (CIs) (time to event data) or as risk ratios (RRs) with 95% CIs (adverse events). Five studies involving a total of 734 participants were eligible for inclusion. We assessed only one study as good quality and the other four as poor quality. However, it was difficult to perform a meta-analysis by extracting aggregate data to synthesise the results as originally planned, mainly because not all studies reported the same outcomes as those chosen for this review. No significant differences favoured VGB or CBZ in terms of time to treatment withdrawal and time to achieve six-month remission after dose stabilisation from randomisation, but results did show a disadvantage for VGB on time to first seizure after randomisation. Compared with CBZ, VGB was associated with more occurrences of weight gain and fewer occurrences of skin rash and drowsiness. No differences in visual field defects and visual disturbances were noted. Data are currently insufficient to address the risk-benefit balance of VGB versus CBZ monotherapy for epilepsy. Given the high prevalence of visual field defects reported in an existing systematic review of observational studies (Maguire 2010), VGB monotherapy should be prescribed with caution for epilepsy and should not be considered a first-line choice. If necessary, the visual field should be frequently assessed. Future research should focus on investigating the reasons for visual field defects and exploring potential prevention strategies. Moreover, future monotherapy studies of epilepsy should report results according to the recommendations of the International League Against Epilepsy (ILAE) Commission, and methodological quality should be improved.

Estimating Lead Time Gained by Optical Coherence Tomography in Detecting Glaucoma before Development of Visual Field Defects

To estimate the diagnostic accuracy and lead time gained by retinal nerve fiber layer (RNFL) thickness measurements from optical coherence tomography (OCT) for detecting glaucoma before the development of visual field defects. Observational cohort study. The study group included 75 eyes of 75 patients suspected of having glaucoma. These eyes had normal standard automated perimetry (SAP) at baseline and demonstrated repeatable (3 consecutive) abnormal tests during a median follow-up of 6.3 years. A control group of 75 eyes of 75 healthy subjects matched by age and number of OCT tests during follow-up was included. The RNFL thickness measurements were obtained at the time of development of the earliest SAP defect (time 0) and also at times -1, -2, -3, and so forth, corresponding to 1 year, 2 years, 3 years, and so forth, before the development of field loss. The OCT measurements at corresponding intervals were analyzed for controls. Time-dependent receiver operating characteristic (ROC) curves were used to evaluate diagnostic accuracy of OCT. Areas and sensitivities of ROC curve at fixed specificities at different times before development of field loss. At the date of conversion to the earliest visual field defect (time 0), mean ± standard deviation average RNFL thickness was 75.0±9.8 μm in glaucomatous eyes and 90.6±8.0 μm for controls (P < 0.001). Significant differences were seen up to 8 years before development of visual field defects (86.3±8.2 μm vs. 91.4±7.6 μm, respectively; P = 0.021). The ROC curve areas decreased with increasing times before detection of field defects. At times 0, -4, and -8 years, ROC curve areas were 0.87, 0.77, and 0.65, respectively. At 95% specificity, up to 35% of eyes had abnormal average RNFL thickness 4 years before development of visual field loss and 19% of eyes had abnormal results 8 years before field loss. Assessment of RNFL thickness with OCT was able to detect glaucomatous damage before the appearance of visual field defects on SAP. In many subjects, significantly large lead times were seen when applying OCT as an ancillary diagnostic tool.

Visual and structural prognosis of the untreated fellow eyes of unilateral normal tension glaucoma patients.

To investigate the visual and structural prognosis of untreated initial non-glaucomatous fellow eyes of unilateral normal tension glaucoma (NTG) patients. In this retrospective observational cohort study, 50 NTG patients with unilateral visual field (VF) loss and no VF defect, retinal nerve fiber layer (RNFL) defect or neuroretinal rim (NRR) notching in the fellow eyes, and those who had initial non-glaucomatous fellow eyes untreated were included. For the fellow eyes, the development of VF defect, RNFL defect, and NRR notching was inspected retrospectively by two observers. Baseline clinical characteristics including initial intraocular pressure (IOP), central corneal thickness, and spherical equivalent (SE) were compared between glaucomatous and fellow eyes. During the mean follow-up period of 8.77 ± 2.92 years, five patients (10 %) developed RNFL defect and four patients (8 %) developed NRR notching in the fellow eye. Among six patients (12 %) who had developed either RNFL defect or NRR notching, only three patients (6 %) developed VF loss in 1.81, 3.09, and 9.27 years respectively. The initial IOP was significantly higher (p = 0.031), SE was more myopic (p = 0.025), and the occurrence of disc hemorrhage (p = 0.049) was significantly higher in glaucomatous eyes than that in fellow eyes. The incidence of glaucoma development in the fellow eye is rather low. Therefore, the initial non-glaucomatous fellow eye of the unilateral NTG patient may be observed without treatment until glaucoma develops.

Frequency-Doubling Technology Perimetry for Detection of the Development of Visual Field Defects in Glaucoma Suspect Eyes

While standard automated perimetry (SAP) remains the reference standard for evaluation of visual field (VF) defects in glaucoma, this study demonstrates that frequency-doubling technology (FDT) perimetry is effective in monitoring visual field progression and may detect the onset of visual field defects earlier than SAP. To compare detection of the development of VF defects, rate of change of VF loss, and risk factors for progression between SAP and matrix FDT perimetry in glaucoma suspect and ocular hypertensive eyes. A total of 113 glaucoma suspect and ocular hypertensive eyes from 76 patients with normal SAP and FDT perimetry results at baseline were prospectively followed up for SAP and FDT perimetry testing at approximately 4-month intervals for 30 months or longer. Patients were consecutively enrolled and followed up from January 2, 2008, to February 28, 2012, at the Hong Kong Eye Hospital, Chinese University of Hong Kong. Visual field progression was defined by the development of VF defects confirmed by 3 or more consecutive examinations at a cluster of 3 or more (less conservative) or 4 or more (more conservative) locations. The rates of change of mean deviation and pattern standard deviation were evaluated with linear mixed models and the risk factors for VF progression were computed with Cox proportional hazard models. During a median study period of 3.4 years, 8.0% of eyes developed VF defects detected by FDT perimetry, 6.2% by SAP, and 4.4% by both using the less-conservative criteria. The detection dropped to 6.2%, 4.4%, and 2.7%, respectively, when the more-conservative criteria were applied. The rate of change of pattern standard deviation was significantly faster for FDT perimetry than SAP (P < .001). Baseline average retinal nerve fiber layer thickness and the number of clock hours of abnormal retinal nerve fiber layer measurement were associated with increased risk for VF progression for both SAP and FDT perimetry. Frequency-doubling technology perimetry would be useful to monitor the onset of VF defects in glaucoma and may detect VF defects not evident in SAP.

Visual field defects due to optic disk drusen in children

Optic nerve head drusen (ONHD) are deposits due to abnormalities in axonal metabolism and degeneration. Studies so far have focused on adults. Our aim was to study the effect of ONHD on visual function as well as optic nerve head structure using optical coherence tomography (OCT) in children. Subjects younger than 18 years of age with ONHD and who had a reliable visual field defect in at least one eye due to ONHD were considered for inclusion. All subjects underwent an extensive ophthalmic examination including best-corrected visual acuity (BCVA), funduscopy, and SITA 24-2 standard automated perimetry. OCT scanning was performed using Cirrus-HD Model 4000. Retinal nerve fiber layer (RNFL) thickness data were compared with a group of age-matched healthy children. Fifteen children were included, with a mean age of 13 years (range 7 to 17 years). BCVA was 1.0 in all eyes, except in a child with concomitant esotropia. ONHD were bilateral in 13 children. Among the 28 eyes with ONHD, 12 (43%) were classified as type 1 (buried), eight (29%) as type 2 (ringed) and eight (29%) as type 3 (superficial). All children had a visual field defect in at least one eye, according to the inclusion criteria; however, two eyes (7%) had no defect in spite of the presence of ONHD. Five eyes showed an isolated enlarged blind spot (18%), 15 cases showed a nasal defect (54%), and six eyes showed a constricted visual field (21%). RNFL thickness was higher in type 1 and 2 ONHD than in the control group, although these differences were only significant for the average, superior, and inferior quadrant thicknesses in type 1 and the inferior quadrant in type 2. RNFL thickness was lower in type 3 ONHD than in the control group, although these differences were only significant for the average, superior, and nasal quadrant thicknesses. ONHD may lead to the development of visual field defects, even in children. In initial stages, ONHD produce an increase in RNFL thickness as measured with OCT. As drusen develop and become superficial, the RNFL thickness decreases. The temporal quadrant is often undamaged, probably reflecting the preservation of central visual acuity.

Retinal Ganglion Cell Count Estimates Associated with Early Development of Visual Field Defects in Glaucoma

To estimate retinal ganglion cell (RGC) losses associated with the earliest development of visual field defects in glaucoma. Observational cohort study. The study group included 53 eyes of 53 patients with suspected glaucoma who were followed as part of the Diagnostic Innovations in Glaucoma (DIGS) study. These eyes had normal standard automated perimetry (SAP) visual fields at baseline and developed repeatable (3 consecutive) abnormal test results during a median follow-up of 6.7 years. An age-matched control group of 124 eyes of 124 healthy subjects recruited from the general population was included. Estimates of RGC counts were obtained using a previously published model that combines estimates of RGC numbers from SAP sensitivity thresholds and retinal nerve fiber layer (RNFL) thickness measurements with spectral domain optical coherence tomography (SD-OCT). For eyes converting to glaucoma, estimates of RGC counts were obtained at the time (within ± 3 months) of the first abnormal visual field, representing the time of earliest detection of visual field losses. Estimates of RGC counts in eyes converting to glaucoma versus healthy eyes. The average RGC count estimate in the eyes with early visual field defects was 652057 ± 115829 cells, which was significantly lower than the average of 910 584 ± 142 412 cells found in healthy eyes (P < 0.001). Compared with the average number of RGCs in the healthy group, glaucomatous eyes had an average RGC loss of 28.4%, ranging from 6% to 57%, at the time of the earliest visual field defect on SAP. Retinal ganglion cell counts performed significantly better than the SD-OCT average RNFL thickness parameter in discriminating glaucomatous from healthy eyes with receiver operating characteristic curve areas of 0.95 ± 0.02 versus 0.88 ± 0.03, respectively (P = 0.001). Glaucomatous eyes with the earliest detectable visual field loss on automated perimetry may already show substantial loss of RGCs. Empirical estimates of RGC counts combining structural and functional tests agreed closely with previous histologic reports on the number of RGCs associated with early visual fields defects on SAP.

Nine-Year Incidence of Open-Angle Glaucoma in the Barbados Eye Studies

To determine the 9-year incidence of open-angle glaucoma (OAG) in African-descent participants of the Barbados Eye Studies. Nine-year cohort study with 81% to 85% participation. Three thousand two hundred twenty-two persons without definite OAG at baseline, at risk of developing OAG at follow-up. The standardized protocol included automated perimetry and various ophthalmic measurements, with a comprehensive ophthalmologic examination for those referred. Fundus photographs were evaluated independently by masked graders. Incidence was estimated by the product-limit approach. Relative risk (RR) ratios with 95% confidence intervals (CIs) were based on Cox regression models with discrete time. Nine-year incidence of definite OAG, based on the development of visual field defects and glaucomatous optic neuropathy, with ophthalmologic confirmation. The 9-year incidence of definite OAG was 4.4% (95% CI, 3.7%-5.2%), or an average of 0.5%/year, based on 125 new cases. Incidence increased greatly with age, from 2.2% at ages 40 to 49 years to 7.9% at ages 70 years or older, and tended to be higher in men than women (4.9% vs. 4.1%; RR, 1.3; 95% CI, 0.9-1.8). More than half (53%) of new cases were undetected, and of these, one third had intraocular pressure of 21 mmHg or less. When 141 persons developing suspected/probable OAG were considered, the total incidence was 9.4% (8.4%-10.6%), averaging approximately 1%/year, also increasing with age, and significantly higher in men than women (10.7% vs. 8.6%; RR, 1.31; 95% CI, 1.02-1.67). These new data provide a measure of the long-term risk of OAG in an African-descent population, which is markedly higher than in persons of European ancestry. Results confirm the increased risk with age and in men. The incidence data fill a gap in our understanding of OAG risk and have implications for public health policy and planning; they also will allow the study of factors related to the risk of OAG development.

Visual field defects and other ophthalmological disturbances associated with vigabatrin.

Vigabatrin has been an important anticonvulsant drug for over 10 years with a reputation for high efficacy and excellent tolerability. However, since 1997, there have been over 25 reports in the literature of visual field defects attributable to the use of this agent. Most are case reports and many have only been reported as abstracts or posters or as letters or short communications. Only a small number of papers give details of patient characteristics. Typically, case reports detail ophthalmological tests such as visual acuity, funduscopic examination, integrity of colour vision, and the nature of the field cut. Many also include various electrophysiological tests which were performed in an attempt to further describe the nature of the visual changes. In order to shed light on the mechanism underlying these visual field changes, many investigators also tested various electrophysiological parameters. However, because electrophysiological testing requires considerable expertise on the part of the technician, this could be a source of variability in results and may also pose a challenge with data interpretation. The magnitude of the problem is difficult to assess. The manufacturer's estimate of incidence of visual field defects with vigabatrin was approximately 0.1%, but incidences estimated in the literature range from 6 to 30%. Since the majority of the published data are in case report form, proof of causation is also very difficult. Two papers that used proper scientific methodology to investigate this condition suggest that vigabatrin causes these changes; however, there needs to be further studies with larger populations to answer this question definitively. There is a lack of data on the dose-response characteristics of vigabatrin and the development of visual field defects. The only available data are reports of trends that implicate duration of therapy or cumulative dose. Perhaps the most important area to elucidate is whether or not the visual field defects are reversible. Data are scare on this subject, but we can hope that data will emerge as follow-up periods become more substantial. There is a need for more complete information regarding several aspects of the mechanistic basis of visual field defects associated with vigabatrin that will allow rational clinical decision making. The treatment choices, both pharmacological and nonpharmacological, for patients with refractory epilepsy have grown substantially in the last few years. Thus, it is doubtful that the clinical positioning of vigabatrin is likely to change in the future from that of a very valuable 'niche drug', with emphasis on paediatric usage.

IMAGING OF THE OPTIC NERVE HEAD AND NERVE FIBER LAYER IN GLAUCOMA

Glaucoma is an optic neuropathy in which irreversible loss of ganglion cells may precede the development of visual field defects and visible optic nerve changes. The diagnosis and management of glaucoma depends on accurate and reliable intraocular pressure (IOP) measurements, visual field analysis, and optic nerve head (ONH) evaluations. The ONH appearance has been used by clinicians since the time of Helmholtz and von Graefe to assess the status of glaucoma; however, the interpretation of the ONH is subjective, and there is wide variation among observers and even among examinations by the same observer. 52,63,73 Stereoscopic ONH photography is one of the simplest technologies that can be used by the clinician, and its utility is extremely high. The cost is relatively low, and stereoscopic ONH photographs permit objective recording of the ONH appearance. 63 These photographs allow the clinician to compare the appearance of the ONH in three dimensions between clinic visits. Despite the low cost and high utility, the Baltimore Eye Study 74 illustrated the potential problem of photography in that high quality stereoscopic photographs could not be obtained in 47% of the glaucoma patients and 22% of normal subjects. Furthermore, stereoscopic ONH photography does not provide a truly objective system for interpretation of ONH appearance and change over time. ONH analyzers preceded the development of the confocal scanning laser ophthalmoscope (CSLO). The ONH analyzers were a necessary first step, but variability and lack of resolution as well as high cost eliminated nearly every device of this type including the Rodenstock Optic Nerve Head Analyzer (G. Rodenstock Instrument GmbH, Postfuch, Germany), Humphrey Retinal Analyzer, and the PAR IS 2000/Topcon IMAGEnet. Even the Glaucoma-Scope, which produced better reproducibility than its predecessors at a relatively low cost, is no longer commercially available. In an era of skepticism but great promise, most still consider visual field testing to be the reference standard, but the earliest visual field defect may indicate as much as 40% ganglion cell death. 59 In addition, automated perimetry is a subjective psychophysical test that demands a high degree of performance for a long period and may not suit those individuals who may have advanced visual, mental, or physical deficits. Therefore, much attention has been placed on developing technology to assist in the early detection and progression of glaucoma. The purpose of this review is to give a brief yet comprehensive look at the technology and literature available to image the optic nerve head and the nerve fiber layer in glaucoma. Much of the current literature concerns the Heidelberg Retina Tomograph ([HRT], Heidelberg Engineering GmbH, Heidelberg, Germany), the Nerve Fiber Analyzer or GDx, and Optical Coherence Tomography (Humphrey Systems Inc, Dublin, CA). Consistent with the past, many new methods such as retinal thickness mapping, multifocal electroretinography (ERG), and pattern ERG have appeared trying to prove themselves, whereas the existing devices are constantly being updated with new knowledge and attempts to increase utility.

Comparison of flow velocity of ophthalmic artery between primary open angle glaucoma and normal tension glaucoma.

This study describes an investigation of the relation between the change of intraocular circulatory dynamics and visual field defect between primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). The method was to determine the blood flow velocity of the ophthalmic artery using colour Doppler imaging and quantitative peak systolic flow velocity, mean envelope velocity, end diastolic velocity, and Pourcelot resistivity index (RI) were determined. The visual field was examined using program 30-2 of the Humphrey field analyser: the mean deviation (MD) and corrected pattern standard deviation (CPSD) were calculated as indices for visual field defects. There were 25 patients with POAG and 25 patients with NTG. There were no significant differences in all the four indices of the ophthalmic arterial flow and in both of visual field indices between patients with POAG and those with NTG. However, NTG patients alone showed a statistically significant correlation between RI and MD. The results suggest the vascular resistance of the ophthalmic artery may be associated with the development of visual field defect in NTG patients.