The Photopic Negative Response: An Objective Measure of Retinal Ganglion Cell Function in Patients With Leber's Hereditary Optic Neuropathy.

Purpose: The photopic negative response (PhNR) is a slow negative component of a flash photopic full-field ERG that has been shown to be specific for retinal ganglion cell (RGC) activity. Direct evaluation of RGC function is desirable in patients with Leber's hereditary optic neuropathy (LHON) in which the loss of central acuity can make it difficult to monitor patients with standard metrics. The purpose of this study was to evaluate the use of PhNR as an objective noninvasive clinical metric in LHON. Methods: Full-field photopic ERG recordings were collected in subjects with the mt.11778G>A/ND4 LHON mutation using a red on blue stimulus. The PhNR was identified using a computer-based automated detection system, and data were manually examined to remove movement artifacts. Results: The PhNR amplitude was compared between controls (n = 13), carriers (n = 17), and affected (n = 6). Mean PhNR amplitude decreased significantly across groups (P < 0.0001). Post hoc Tukey's test revealed a significant decrease in PhNR amplitude between carriers and controls (P < 0.05) and between carriers and affected (P < 0.01). Conclusions: We are able to demonstrate that the PhNR amplitude is significantly decreased in patients affected by LHON compared to carriers in a well-described pedigree. Surprisingly, there was also a decrease in PhNR in carriers, suggesting potential subclinical RGC dysfunction in some carriers. This is important in patients affected with LHON who typically have a dense central scotoma. The PhNR may be a useful objective outcome measure for future clinical trials.

Sweep visually evoked potentials and visual findings in children with West syndrome.

BACKGROUND: West syndrome (WS) is a type of early childhood epilepsy characterized by progressive neurological development deterioration that includes vision. AIM: To demonstrate the clinical importance of grating visual acuity thresholds (GVA) measurement by sweep visually evoked potentials technique (sweep-VEP) as a reliable tool for evaluation of the visual cortex status in WS children. METHODS: This is a retrospective study of the best-corrected binocular GVA and ophthalmological features of WS children referred for the Laboratory of Clinical Electrophysiology of Vision of UNIFESP from 1998 to 2012 (Committee on Ethics in Research of UNIFESP n° 0349/08). The GVA deficit was calculated by subtracting binocular GVA score (logMAR units) of each patient from the median values of age norms from our own lab and classified as mild (0.1-0.39 logMAR), moderate (0.40-0.80 logMAR) or severe (>0.81 logMAR). Associated ophthalmological features were also described. RESULTS: Data from 30 WS children (age from 6 to 108 months, median = 14.5 months, mean ± SD = 22.0 ± 22.1 months; 19 male) were analyzed. The majority presented severe GVA deficit (0.15-1.44 logMAR; mean ± SD = 0.82 ± 0.32 logMAR; median = 0.82 logMAR), poor visual behavior, high prevalence of strabismus and great variability in ocular positioning. The GVA deficit did not vary according to gender (P = .8022), WS type (P = .908), birth age (P = .2881), perinatal oxygenation (P = .7692), visual behavior (P = .8789), ocular motility (P = .1821), nystagmus (P = .2868), risk of drug-induced retinopathy (P = .4632) and participation in early visual stimulation therapy (P = .9010). CONCLUSIONS: The sweep-VEP technique is a reliable tool to classify visual system impairment in WS children, in agreement with the poor visual behavior exhibited by them.

Contributing factors to VEP grating acuity deficit and inter-ocular acuity difference in children with cerebral visual impairment.

PURPOSE: To investigate contributing factors to visual evoked potential (VEP) grating acuity deficit (GAD) and inter-ocular acuity difference (IAD) measured by sweep-VEPs in children with cerebral visual impairment (CVI). METHODS: VEP GAD was calculated for the better acuity eye by subtracting acuity thresholds from mean normal VEP grating acuity according to norms from our own laboratory. Deficits were categorized as mild (0.17 ≤ deficit < 0.40 log units), moderate (0.40 ≤ deficit < 0.70 log units) or severe (deficit ≥0.70 log units). Maximum acceptable IAD was 0.10 log units. RESULTS: A group of 115 children (66 males-57 %) with ages ranging from 1.2 to 166.5 months (median = 17.7) was examined. VEP GAD ranged from 0.17 to 1.28 log units (mean = 0.68 ± 0.27; median = 0.71), and it was mild in 23 (20 %) children, moderate in 32 (28 %) and severe in 60 (52 %). Severe deficit was significantly associated with older age and anti-seizure drug therapy. IAD ranged from 0 to 0.49 log units (mean = 0.06 ± 0.08; median = 0.04) and was acceptable in 96 (83 %) children. Children with strabismus and nystagmus had IAD significantly larger compared to children with orthoposition. CONCLUSION: In a large cohort of children with CVI, variable severity of VEP GAD was found, with more than half of the children with severe deficits. Older children and those under anti-seizure therapy were at higher risk for larger deficits. Strabismus and nystagmus provided larger IADs. These results should be taken into account on the clinical management of children with this leading cause of bilateral visual impairment.

Visual acuity and retinal function in patients with Bardet-Biedl syndrome.

OBJECTIVE: Bardet-Biedl syndrome is a genetic, multisystem disorder that causes severe visual impairment. This condition is characterized by retinal dystrophy, obesity, digit anomalies, renal disease, and hypogonadism. The purpose of this study was to analyze visual acuity and full-field electroretinogram findings in patients with the Bardet-Biedl syndrome phenotype. METHODS: The visual acuity of a group of 23 patients (15 males) with ages ranging from 6-36 years (mean = 15.8 ± 6.4; median = 14.7) was assessed. Retinal function was evaluated by full-field electroretinography, and dark-adapted thresholds were assessed. RESULTS: Visual acuity in the better-seeing eye was 20/40 or better in 5 patients (21.7%), 20/50-20/150 in 13 (56.5%) patients, 20/200-20/400 in 2 (8.7%) patients and worse than 20/400 in one (4.3%) patient. The mean acuity in the better-seeing eye was 0.7 ± 0.6 logMAR (20/100, Snellen equivalent). Scotopic rod and maximal responses were nondetectable in 21 (91.3%) patients, and cone responses were non-detectable in 15 (65.2%) patients. Elevated dark-adapted visual thresholds were observed in all 19 patients who were able to be assessed, with 10 (52.6%) patients having thresholds greater than 30 dB. CONCLUSIONS: In a relatively young cohort of patients with Bardet-Biedl syndrome, only 21% had 20/40 or better vision. ERG scotopic responses were absent in the majority of cases, with cone responses being observed in less than half of cases. These findings showed the early deleterious effects in retinal function and visual acuity caused by this condition.

Visual acuity and retinal function in patients with Bardet-Biedl syndrome

OBJECTIVE: Bardet-Biedl syndrome is a genetic, multisystem disorder that causes severe visual impairment. This condition is characterized by retinal dystrophy, obesity, digit anomalies, renal disease, and hypogonadism. The purpose of this study was to analyze visual acuity and full-field electroretinogram findings in patients with the Bardet-Biedl syndrome phenotype. METHODS: The visual acuity of a group of 23 patients (15 males) with ages ranging from 6-36 years (mean = 15.8±6.4; median = 14.7) was assessed. Retinal function was evaluated by full-field electroretinography, and dark-adapted thresholds were assessed. RESULTS: Visual acuity in the better-seeing eye was 20/40 or better in 5 patients (21.7 percent), 20/50-20/150 in 13 (56.5 percent) patients, 20/200-20/400 in 2 (8.7 percent) patients and worse than 20/400 in one (4.3 percent) patient. The mean acuity in the better-seeing eye was 0.7±0.6 logMAR (20/100, Snellen equivalent). Scotopic rod and maximal responses were nondetectable in 21 (91.3 percent) patients, and cone responses were non-detectable in 15 (65.2 percent) patients. Elevated darkadapted visual thresholds were observed in all 19 patients who were able to be assessed, with 10 (52.6 percent) patients having thresholds greater than 30 dB. CONCLUSIONS: In a relatively young cohort of patients with Bardet-Biedl syndrome, only 21 percent had 20/40 or better vision. ERG scotopic responses were absent in the majority of cases, with cone responses being observed in less than half of cases. These findings showed the early deleterious effects in retinal function and visual acuity caused by this condition.

Discriminação de cores em profissionais da área técnica de empresa de material fotográfico / Color vision discrimination in employees of a photographic laboratory

OBJETIVO: Avaliar a discriminação de cores em profissionais da área técnica de empresa de material fotográfico. MÉTODOS: Foram incluídos 47 profissionais (37 homens) com idades variando de 18 a 41 anos (média 27,2 ± 5,6 anos), alocados em área técnica especializada em calibração e assistência de máquinas de revelação de fotos em 1 hora. O tempo de trabalho nesta atividade variou de 1 mês a 18 anos. O grupo controle constituiu de 22 voluntários (5 homens) com idades variando de 18 a 55 anos (Média 25,0 ± 10,6 anos). A discriminação de cores foi avaliada com o teste Farnsworth-Munsell 100-Hue. Os critérios de inclusão para os dois grupos foram: acuidade visual com a melhor correção óptica e > 0,1 logMAR, fundo de olho normal, ausência de doenças hereditárias, sintomas visuais ou cirurgia ocular prévia. RESULTADOS: Vinte e quatro (51 por cento) profissionais do laboratório fotográfico apresentaram discriminação superior, comparados a 18 por cento dos voluntários. Vinte (42 por cento) apresentaram discriminação de cores dentro da média e 3 (7 por cento) apresentaram discriminação inferior. O índice de erros foi estatisticamente menor no grupo de profissionais quando comparado ao grupo controle (T=968.000, P=0,011). Não houve correlação entre o tempo de atividade na profissão e os resultados da discriminação de cores. CONCLUSÕES: Os profissionais da área técnica da empresa fotográfica mostraram discriminação de cores superior à do grupo controle.

PURPOSE: The objective of this study was to evaluate chromatic discrimination in employees of a photographic laboratory. METHODS: A total of 47 professional employees of the technical area devoted to calibration and technical assistance for one-hour photo machines (37 men), aged 18 to 41 years (mean of 27.2 ± 5.6 years). The period working in this function ranged from one month to 18 years. Twenty-two normal volunteers (5 men) aged 18-55 years (mean of 25.0 ± 10.6 years) were tested as a control group. Color discrimination was evaluated by the Farnsworth-Munsell 100-Hue test. The inclusion criteria were visual acuity > 0.1 logMAR, normal fundus, absence of hereditary eye disease, absence of visual symptoms or ocular surgery. RESULTS: Twenty-four people (51 percent) of the professional group presented superior color discrimination when compared to 18 percent of the control group. Twenty people (42 percent) presented average discrimination and 3 (7 percent) presented inferior discrimination. Color vision discrimination was statistically better in professionals when compared to controls (T=968.000, P=0.011). There was no correlation between the period working in the function and color discrimination. CONCLUSIONS: Technical professionals working in a photographic laboratory showed better color discrimination than controls.

[Color vision discrimination in employees of a photographic laboratory]. / Discriminação de cores em profissionais da área técnica de empresa de material fotográfico.

PURPOSE: The objective of this study was to evaluate chromatic discrimination in employees of a photographic laboratory. METHODS: A total of 47 professional employees of the technical area devoted to calibration and technical assistance for one-hour photo machines (37 men), aged 18 to 41 years (mean of 27.2 +/- 5.6 years). The period working in this function ranged from one month to 18 years. Twenty-two normal volunteers (5 men) aged 18-55 years (mean of 25.0 +/- 10.6 years) were tested as a control group. Color discrimination was evaluated by the Farnsworth-Munsell 100-Hue test. The inclusion criteria were visual acuity >or= 0.1 logMAR, normal fundus, absence of hereditary eye disease, absence of visual symptoms or ocular surgery. RESULTS: Twenty-four people (51%) of the professional group presented superior color discrimination when compared to 18% of the control group. Twenty people (42%) presented average discrimination and 3 (7%) presented inferior discrimination. Color vision discrimination was statistically better in professionals when compared to controls (T=968.000, P=0.011). There was no correlation between the period working in the function and color discrimination. CONCLUSIONS: Technical professionals working in a photographic laboratory showed better color discrimination than controls.