Exp. Clin. Endocrino!. Vol. 97, No. 2/3, 1991, PP. 344-347
J. A. Barth, Leipzig
Department of Ophthalmology (Head: Prof. A. Tarkkanen, M.D.), Endocrine Research Laboratory (Head: Prof. D.-A. Lamberg, M.D.), and Third Department of Medicine (Head: Prof. P. Pentikäinen, M.D.), University of Helsinki/Finland
Visual Evoked Potentials in Basedow's Ophthalmopathy before
and after Orbital Decompression or Retrobulbar Irradiation
Summary. VEP are an objective and a more sensitive sign of optical neuropathy in Graves' ophthalmopathy than is visua! acuity. A correlation exists between VEP and the changes in the external eye muscles as visualized on CT scans. VEP should always be registered if CT changes are present. Improvement of optic neuropathy as evaluated from VEP seems to be remarkably infrequent.
Introduction Optic neuropathy of Graves' disease develops insidiously. Decrease of visual acuity is commonly regarded as an important sign. Visual evoked potentials (VEP) are, however, an objective and more sensitive indicator of neuropathy (Wijngaarde and van Lith, 1979;
Neigel et al., 1988). It seemed of interest to report the present pilot study because of a long follow-up.
Patients and Methods The material comprised 15 patients with Graves' disease of which 7 were submitted to bilateral orbital decompression and 3 to retrobulbar irradiation whereas 5 patients did not need any particular therapy for the eye syndrome. The treated patients had eye signs of classes (2, 3) 4 and 6 according to the classification of the American Thyroid Association (Werner, 1977), the 5 patients not treated belonged to classes 2 and 3. Requirements for active therapy was based upon clinical grounds. The patients were euthyroid at the time of treatment of the eye syndrome. Sixteen healthy subjects served as controls. In addition to the clinical examination and the measurement of the visual acuity (VA) VEP were registered in all and computerized tomography (CT) performed in 14 treated patients. The findings on CT scans were graded arbitrarily 0, barely observable, and 1 to 3. VEP were registered after stimulation with flashes of 0.2 J at a rate of 1 pulse/s. The latency (ms) and amplitudes (p.tV) at N and P20 were evaluated. In the treated patients examinations for VA and VEP were repeated 1/2 and 5-7 years after treatment whereas the patients not treated and the controls were examined only once.
Downloaded by: Universite Laval. Copyrighted material.
K. SETALA, C. RAITTA, M. VÄLIMÄiu, K. KATEVUO and B.-A. LAMBERG
345
K. SETÄLÄ et. al., Visual Evoked Potentials
Results Visual acuity. In the 7 operated patients (13 eyes because one patient had a cataract on one eye which did not, however, prevent the registration of VEP) the VA was initially nor-
mal in 8 eyes and depressed in S (Table 1). Five to seven years following treatment a decrease was observed in 1 initially normal and 1 initially depressed eye but amelioration only in 1 eye. In the 3 irradiated patients (6 eyes) VA was normal and remained so in all (läble 1).
läble 1
Changes in visual acuity and VEP during a
5-7 years follow-up
Operated patients (No of eyes)
5-7 years
Visual acuity Normal
8
Depressed
5
7
Unchanged
10
Further decrease Ameliorated
2
Unchanged Further deterioration Ameliorated
4
Normal
6
Visual evoked potentials Normal Abnormal
O
4
14
5
5
5 5
Irradiated patients (No of eyes) Visual acuity Normal
6
Visual evoked potentials
Abnormal
6
_____P Unchanged Further deterioration Ameliorated
1
3
2
Visual evoked potentials. The mean VEP in the 4 groups of subjects studied are shown in 'Thble 2. The latency at N in the two treated groups (14 eyes in the operated and 6 eyes in the irradiated group) was significantly longer (P
J. A. Barth, Leipzig
Department of Ophthalmology (Head: Prof. A. Tarkkanen, M.D.), Endocrine Research Laboratory (Head: Prof. D.-A. Lamberg, M.D.), and Third Department of Medicine (Head: Prof. P. Pentikäinen, M.D.), University of Helsinki/Finland
Visual Evoked Potentials in Basedow's Ophthalmopathy before
and after Orbital Decompression or Retrobulbar Irradiation
Summary. VEP are an objective and a more sensitive sign of optical neuropathy in Graves' ophthalmopathy than is visua! acuity. A correlation exists between VEP and the changes in the external eye muscles as visualized on CT scans. VEP should always be registered if CT changes are present. Improvement of optic neuropathy as evaluated from VEP seems to be remarkably infrequent.
Introduction Optic neuropathy of Graves' disease develops insidiously. Decrease of visual acuity is commonly regarded as an important sign. Visual evoked potentials (VEP) are, however, an objective and more sensitive indicator of neuropathy (Wijngaarde and van Lith, 1979;
Neigel et al., 1988). It seemed of interest to report the present pilot study because of a long follow-up.
Patients and Methods The material comprised 15 patients with Graves' disease of which 7 were submitted to bilateral orbital decompression and 3 to retrobulbar irradiation whereas 5 patients did not need any particular therapy for the eye syndrome. The treated patients had eye signs of classes (2, 3) 4 and 6 according to the classification of the American Thyroid Association (Werner, 1977), the 5 patients not treated belonged to classes 2 and 3. Requirements for active therapy was based upon clinical grounds. The patients were euthyroid at the time of treatment of the eye syndrome. Sixteen healthy subjects served as controls. In addition to the clinical examination and the measurement of the visual acuity (VA) VEP were registered in all and computerized tomography (CT) performed in 14 treated patients. The findings on CT scans were graded arbitrarily 0, barely observable, and 1 to 3. VEP were registered after stimulation with flashes of 0.2 J at a rate of 1 pulse/s. The latency (ms) and amplitudes (p.tV) at N and P20 were evaluated. In the treated patients examinations for VA and VEP were repeated 1/2 and 5-7 years after treatment whereas the patients not treated and the controls were examined only once.
Downloaded by: Universite Laval. Copyrighted material.
K. SETALA, C. RAITTA, M. VÄLIMÄiu, K. KATEVUO and B.-A. LAMBERG
345
K. SETÄLÄ et. al., Visual Evoked Potentials
Results Visual acuity. In the 7 operated patients (13 eyes because one patient had a cataract on one eye which did not, however, prevent the registration of VEP) the VA was initially nor-
mal in 8 eyes and depressed in S (Table 1). Five to seven years following treatment a decrease was observed in 1 initially normal and 1 initially depressed eye but amelioration only in 1 eye. In the 3 irradiated patients (6 eyes) VA was normal and remained so in all (läble 1).
läble 1
Changes in visual acuity and VEP during a
5-7 years follow-up
Operated patients (No of eyes)
5-7 years
Visual acuity Normal
8
Depressed
5
7
Unchanged
10
Further decrease Ameliorated
2
Unchanged Further deterioration Ameliorated
4
Normal
6
Visual evoked potentials Normal Abnormal
O
4
14
5
5
5 5
Irradiated patients (No of eyes) Visual acuity Normal
6
Visual evoked potentials
Abnormal
6
_____P Unchanged Further deterioration Ameliorated
1
3
2
Visual evoked potentials. The mean VEP in the 4 groups of subjects studied are shown in 'Thble 2. The latency at N in the two treated groups (14 eyes in the operated and 6 eyes in the irradiated group) was significantly longer (P
