Maija Mäntyjärvi

No reversion in vigabatrin-associated visual field defects

Sixty adult patients with partial epilepsy who have been treated with vigabatrin for 7 months to 14 years as mono- or add-on therapy were examined with repeated kinetic Goldmann perimetries to evaluate the prevalence, risk factors, and long-term outcome of vigabatrin-associated visual field defects. A follow-up examination was performed after 4 to 38 months (mean, 15 ± 7) in 55 patients, 29 of whom had discontinued vigabatrin therapy. Neither reversion nor progression in visual field constriction was observed.

Color vision in epilepsy patients treated with vigabatrin or carbamazepine monotherapy

PURPOSE To investigate color vision in epilepsy patients treated with vigabatrin or carbamazepine monotherapy and to evaluate the association between vigabatrin-induced visual field defects and dyschromatopsia. DESIGN Nonrandomized comparative trial. PARTICIPANTS Thirty-two epilepsy patients treated with vigabatrin monotherapy, 18 patients treated with carbamazepine monotherapy, and 47 age-matched healthy controls were examined. MAIN OUTCOME MEASURES Color vision was examined with Standard Pseudoisochromatic Plates 2 (SPP2) screening test, Farnsworth-Munsell 100 (FM 100) hue test, and Color Vision Meter 712 anomaloscope. RESULTS Abnormal color perception was found in 32% of the epilepsy patients treated with vigabatrin monotherapy and 28% of the epilepsy patients treated with carbamazepine monotherapy. The total error score in the Farnsworth-Munsell 100 hue test was abnormally high in the vigabatrin monotherapy patients who had concentrically constricted visual fields and a statistically significant correlation was found between the temporal visual field extents and the age-adjusted Farnsworth-Munsell 100 total error score in vigabatrin monotherapy patients (R = .533, P = 0.003 in the right eye, R = .563, P = 0.001 in the left eye). Four of 31 (12%) vigabatrin monotherapy patients, and 1 of 18 (6%) carbamazepine monotherapy patients had a blue axis in Farnsworth-Munsell 100 hue test. In the anomaloscope, there were a few pathologic findings in both groups. In the SPP2 screening test, a few plates were not seen in both groups. CONCLUSIONS Both examined antiepileptic drugs, vigabatrin and carbamazepine, cause acquired color vision defects. The abnormal color perception seems to be associated with constricted visual fields in the vigabatrin monotherapy patients. The duration of carbamazepine therapy correlates with high FM100 total error score. The best method for detecting dyschromatopsia in patients treated with vigabatrin or carbamazepine was the Farnsworth-Munsell 100 hue test. The SPP2 screening test does not seem to be useful in clinical practice.

Contrast and glare sensitivity in epilepsy patients treated with vigabatrin or carbamazepine monotherapy compared with healthy volunteers

BACKGROUND/AIM Many antiepileptic drugs have influence on visual functions. The aim of this study was to investigate possible changes in contrast sensitivity, macular photostress, and brightness acuity (glare) tests in patients with epilepsy undergoing vigabatrin (VGB) or carbamazepine (CBZ) monotherapy compared with healthy volunteers. METHODS 32 patients undergoing VGB therapy, 18 patients undergoing CBZ therapy, and 35 healthy volunteers were asked to participate in an ophthalmological examination. In the previous study, visual field constrictions were reported in 40% of the patients treated with VGB monotherapy. In the present study, these VGB and CBZ monotherapy patients were examined for photopic contrast sensitivity with the Pelli-Robson letter chart and brightness acuity and macular photostress with the Mentor BAT brightness acuity tester. RESULTS Contrast sensitivity with the Pelli-Robson letter chart showed no difference between these groups and normal subjects (ANOVA: p= 0.534 in the right eye, p= 0.692 in the left eye) but the VGB therapy patients showed a positive correlation between the contrast sensitivity values and the extents of the visual fields in linear regression (R = 0.498, p = 0.05 in the right eye, R = 0.476, p = 0.06 in the left eye). Macular photostress and glare tests were equal in both groups and did not differ from normal values. CONCLUSION The results of this study indicate that carbamazepine therapy has no effect on contrast sensitivity. Vigabatrin seems to impair contrast sensitivity in those patients who have concentrically constricted in their visual fields. Neither GBZ nor VGB affect glare sensitivity.

The amblyopic schoolgirl syndrome.

The occurrence of psychogenic amblyopia in a population of school children was studied. From the population of 14,000 school children under the surveillance of school nurses and doctors, 2280 were referred to the author for an ophthalmological examination during a two-year period. Forty children (1.75%) were diagnosed as having psychogenic amblyopia corresponding to an incidence of 1.4/1000/year. Psychogenic amblyopia was characterized by a high percentage of girls (48 out of 52) and the highest occurrence at the age of 9 to 11 years. There was a wide variation of the duration of the condition, but 37% of the patients recovered within one year. A psychological cause for amblyopia could be revealed in only a few cases. According to the present study psychogenic amblyopia can occur at a relatively high incidence. Awareness of this condition could spare these children from straining, expensive tests.

Predicting of Myopia Progression in School Children

Myopia in 214 school children has been followed from one to nine years. The children have been divided in groups according to the age of onset of myopia and the amount of final myopia at the age of 15 or 16 has been recorded. If myopia started before puberty (at the age of 10 or younger) 70% of the children ended up with myopia of -3.0 to -5.75 D, only 12.5% remained under -3.0 D, and 17.5% had myopia -6.0 D or more. If myopia began at the ages of 11-15, 66.7% remained under -3.0 D, 32.2% reached -3.0 to -5.75 D, and only 1.1% of the children had myopia of -6.0 D or more. Of all the 214 children, 95.8% had myopia less than -6.0 D at the age of 15-16 years. However, the individual variation is very wide, and it is difficult to predict the final amount of myopia in school years in an individual case.

Observations on the use of three different contrast sensitivity tests in children and young adults.

Forty-one children and young adults aged 4 to 25 years (mean 14.5 +/- 6.9, SD) with normal eyes were examined with three different contrast sensitivity tests: the Vistech distance and near test, the Cambridge Low Contrast Gratings test, and the LH-5 Contrast test. In different age groups, the youngest children aged 4 to 9 years had the lowest result values. The results of the older children aged 10 to 15 years and young adults aged 16 to 25 years were close to each other. The range of the results in all tests was large in every age group. The values of contrast sensitivity could not be compared from one test to another; in the Vistech tests the values varied from 10 to 200, in the Cambridge test from 170 to 560, and in the LH-5 test from 5 to 50. Most of the children liked the LH-5 test best, while most of the young adults preferred the Vistech distance test. It is useful to examine children and adults with different contrast sensitivity tests; however, the same test should be used in follow-up examinations.

Visual function in epilepsy patients treated with initial valproate monotherapy

PURPOSE To investigate whether initial valproate (VPA) monotherapy for the treatment of epilepsy causes visual field defects and visual dysfunction. METHODS In a cross-sectional study, visual fields were examined with the kinetic Goldmann and automated Humphrey perimeters, contrast sensitivity function with the Pelli-Robson letter chart and colour vision with the Standard Pseudoisochromatic Plates Part 2 (SPP 2) and Farnsworth-Munsell 100 Hue test (FM 100) in eighteen epilepsy patients (aged 18--50 years, 30.2.+/-10 years, mean+/-S.D.) treated with initial valproate monotherapy for 2--20 years (8.4+/-5.1 years). RESULTS None had vigabatrin-type, concentric visual field defect with the kinetic Goldmann or automated Humphrey perimetries. In the Humphrey perimetry, the mean deviation for the group was within normal limits varying from -2.53 to 0.59 dB (-0.74+/-0.80 dB) in the right eye and from -2.66 to 0.67 dB (-0.78+/-0.82 dB) in the left eye. In the FM 100 test, acquired colour vision deficiency was found in two out of 18 patients (11%, 95% CI: 0--25%). However, the mean total error score was lower in the patient group than in the control group. All patients had normal contrast sensitivity function. CONCLUSIONS The use of VPA in the treatment of epilepsy is not associated with visual field defects similar to vigabatrin, but may induce abnormalities in colour vision.

Visual Function in Patients Treated with the GABAergic Anticonvulsant Drug Tiagabine

AbstractObjective: To evaluate whether the anticonvulsant drug tiagabine is associated with changes in visual function, particularly that of visual field loss. Patients: 15 patients with chronic partial epilepsy treated for 23 to 55 months with tiagabine monotherapy after failure with standard anticonvulsant drug monotherapy were investigated. Main Outcome Measures: The visual field was examined by kinetic perimetry with the Goldmann perimeter and by age-corrected 120 Full Field suprathreshold static perimetry with the Humphrey Field Analyser, contrast sensitivity with the Pelli-Robson letter chart, and colour vision with the Standard Pseudoisochromatic Plates part 2, Farnsworth-Munsell 100 Hue test and Color Vision Meter anomaloscope. Results: None of the patients treated with tiagabine monotherapy had concentric visual field loss. Three patients had localised field loss (two quadrantanoptic and one hemianoptic) from earlier brain lesions. Acquired colour vision defects were found in seven of 14 (50%) examined patients. Contrast sensitivity was within normal ranges. Conclusions: Long-term monotherapy with the GABAergic anticonvulsant drug, tiagabine, showed no effect on visual fields in patients with chronic partial epilepsy. Acquired colour vision defects occurred as often as in patients treated with other anticonvulsant drugs.

Color vision and contrast sensitivity in epilepsy patients treated with initial tiagabine monotherapy

The purpose of the study was to determine whether the use of a GABAergic antiepileptic drug (AED), tiagabine, affects color vision and contrast sensitivity. Twenty newly diagnosed patients with partial epilepsy (aged 19-72 years), receiving tiagabine as their initial monotherapy for 5-41 months were examined. Color vision was examined with the Standard Pseudoisochromatic Plates 2 (SPP2), with the Farnsworth-Munsell 100 Hue Test (FM100) and with the Color Vision Meter 712 (CVM) anomaloscope. Contrast sensitivity was measured with the Pelli-Robson letter chart. Three patients excluded from the color vision evaluation for congenital red-green color vision defects. Seven out of 17 patients (41%) had acquired color vision deficit examined with the FM100. The CVM anomaloscope revealed minor defects in two patients. Contrast sensitivity function was within normal ranges. The present study suggests that AED therapy with tiagabine, like with other established and newer AEDs may interfere with color perception.

Accommodation in Hyperopic and Myopic School Children

Binocular accommodation of 150 consecutive hyperopic and 150 myopic school children was measured during the eye examination. There were 99 girls and 51 boys in the hyperopic group and 100 girls and 50 boys in the myopic group. The ages varied from seven to 16 years. Accommodation of the hyperopic children varied from 4 to 20 D (mean 10.6 +/- 3.4), and in the myopic children also from 4 to 20 D (mean 10.9 +/- 2.5). The difference between these means was not statistically significant. However, hyperopic girls aged 12 to 16 years showed low values of accommodation (mean 9.0 +/- 2.7) compared to the other corresponding age groups. In the second part of the study the refraction of 80 children, aged seven to 15 years, with decreased accommodation was studied retrospectively to see if they had a tendency to become myopic. The follow-up time was from one to eight years, and the accommodation at the beginning of the observation time varied from 2 to 7 D. The mean annual change of the refraction of these children was from -0.03 to -0.17 D. In 34 children there was no change at all, and in 12 children the change of refraction was slightly toward more hyperopia. Only three of these 80 children became myopic during the observation time. This incidence is lower than the incidence of myopia at these ages. Thus, accommodative power of hyperopic and myopic school children appears to be on the same level, and low accommodation does not predict the development of myopic refraction in the school years.