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Biomedical subjects

A Tanikawa

Publications and source records attributed to A Tanikawa.

At least 19 recordsLinked to original sources
PubMed2001

Unilateral cone dysfunction with bull's eye maculopathy.

OBJECTIVE: To report a Japanese subject who presented with an acute-onset, unilateral cone dysfunction with bull's eye maculopathy and to describe the functional changes determined by psychophysical and electrophysiologic tests. DESIGN: A single observational case report. METHODS: In addition to a complete ophthalmic examination, the subject underwent some electrophysiologic and psychophysical tests. MAIN OUTCOME MEASURES: Kinetic visual field test, cone and rod perimetry (two-color perimetry), full-field electroretinograms (ERGs), focal macular ERGs, and multifocal ERGs. RESULTS: The full-field ERGs and two-color perimetry showed a predominant loss of cone function in the right eye, whereas the left eye was normal. Cone perimetry and multifocal ERGs revealed that there were small regions functioning normally and other retinal areas that were severely altered in the right eye. CONCLUSIONS: The topographical function analysis suggested that the disorder affected the retina unevenly. The cause of this rare case of unilateral cone dysfunction with bull's eye maculopathy still remains unknown.

Acute Disease↗
PubMed2001

Eosinophilic pustular folliculitis (Ofuji's disease): indomethacin as a first choice of treatment.

Eosinophilic pustular folliculitis (EPF) is characterized by erythematous patches of large follicular papules and pustules involving mainly the face. Although various treatments have been attempted for EPF, including systemic and topical steroid, diaphenylsulphone, colchicine, minocycline as well as UVB phototherapy, there is no consensus on the first choice of treatment. We report a typical case and summarize 25 patients with EPF treated in our hospital between 1978 and 1998. Indomethacin was most frequently used (12/25) and showed clinical improvement in the majority of the cases (11/12). The effect of indomethacin was usually observed within 1--2 weeks after initiation of treatment. Decrease of peripheral blood eosinophils accompanied the clinical improvement. Thus, indomethacin should be considered as a first choice of treatment for EPF.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2001

Multifocal ERG findings in complete type congenital stationary night blindness.

PURPOSE: To study the multifocal electroretinogram (mfERG) in patients with the complete type of congenital stationary night blindness (cCSNB), which is thought to be due to a defect in neurotransmission from the photoreceptors to the ON-bipolar cells. METHODS: mfERGs were recorded with the VERIS recording system from four patients with cCSNB, none of whom had nystagmus. The stimulus array consisted of 61 hexagons, and the total recording time was approximately 4 minutes. The amplitudes and implicit times of the first- and second-order kernels of the local responses were compared with those from 20 myopic controls. Waveforms of the summed response from all locations were also compared between the two groups. RESULTS: The first-order kernels of the mfERGs of cCSNB patients had normal amplitudes but delayed implicit times for nearly the whole field tested. The second-order kernel was severely attenuated in amplitude in cCSNB patients. The ratios of the second- to first-order kernel amplitudes were significantly reduced in cCSNB and clearly separated the cCSNB group from the control group without any overlap of the values. CONCLUSIONS: The second-order kernel, which is involved in adaptative mechanism of the retina to repeated flashes, is selectively reduced in cCSNB. The delay of the implicit times of the first-order kernel in patients with cCSNB may be related to the severe amplitude reduction of the second-order kernel.

Adolescent↗
PubMed2001

A contact lens electrode with built-in high intensity white light-emitting diodes. A contact lens electrode with built-in white LEDs.

We determined the clinical usefulness of a new contact lens electrode with built-in, white light-emitting diodes (LEDs) for full-field electroretinograms (ERGs). Three, high-brightness white LEDs were incorporated into a contact lens electrode and served as the source for the stimulus and the background. The stimulus intensity, stimulus duration and background illumination were regulated by a small LED control device. Maximum stimulus and background intensities were 3.9 and 3.6 log cd/m2, respectively. We successfully recorded intensity-response series for scotopic and photopic ERGs. We also recorded a duration-series for photopic ERGs, and ERGs that were comparable to the ISCEV standardized ERGs. The compactness and ease of using this system suggest that it will be clinically useful under different conditions.

Adult↗
PubMed2000

Neovascular Maculopathy Associated with Rubella Retinopathy.

Background: We report three eyes of two patients with rubella retinopathy which were associated with choroidal neovascularization in the macula.Cases: A 7-year-old girl (case 1) and a 12-year-old girl (case 2) whose mothers had suffered rubella during their pregnancy revealed typical rubella retinopathy in both eyes and neovascular maculopathy in one eye at their initial visit to our clinic. Neovascular maculopathy developed in another eye of case 1 after a follow-up of 10 months.Results: The clinical characteristics indicated that (1) sudden visual loss occurs in children, (2) there is no external trigger such as eye injury, and (3) the visual prognosis appears relatively good.Conclusion: Although neovascular maculopathy is rare in pediatric disease, the rubella retinopathy may have the potential to cause neovascular maculopathy.

Journal Article↗
PubMed2000

Multifocal electroretinogram in occult macular dystrophy.

PURPOSE: Occult macular dystrophy (OMD) is an unusual macular dystrophy presenting with an essentially normal fundus and fluorescein angiography but with progressive central visual loss. The authors studied the function of local retinal areas in the posterior pole of patients with OMD using multifocal electroretinograms (ERGs). METHODS: Multifocal ERGs were recorded using the Visual Evoked Response Imaging System with 61 hexagonal elements within a visual field of 30 degrees radius from 8 OMD patients and 20 age-matched, normal subjects. The amplitudes and implicit times of the patients and normal control subjects were compared at the various retinal eccentricities. RESULTs. The amplitudes of the multifocal ERGs in the OMD patients were markedly reduced in the central 7 degrees of the fovea. The difference of the ERG amplitudes between OMD and normal subjects became smaller toward the peripheral retina. Most OMD patients had slight but significantly delayed implicit times across the whole testing field, and the differences between the OMD and the normal subjects did not change with retinal eccentricity. CONCLUSIONS: Our results for multifocal ERG amplitudes support the idea that OMD patients have localized retinal dysfunction distal to the ganglion cells in the central retina. The delayed implicit times across the whole test field suggest that the retinal dysfunction has a broader boundary than expected by ERG amplitudes and psychophysical perimetric results.

Adult↗
PubMed2000

[Neovascular maculopathy associated with rubella retinopathy].

BACKGROUND: We report three eyes of two patients with rubella retinopathy which were associated with choroidal neovascularization in the macula. CASES: A 7-year-old girl (case 1) and a 12-year-old girl (case 2) whose mothers had suffered rubella during their pregnancy revealed typical rubella retinopathy in both eyes and neovascular maculopathy in one eye at their initial visit to our clinic. Neovascular maculopathy developed in another eye of case 1 after a follow-up of 10 months. RESULTS: The clinical characteristics indicated that 1. sudden visual loss occurs in children, 2. there is no external trigger such as eye injury, and 3. the visual prognosis appears relatively good. CONCLUSION: Although neovascular maculopathy is rare in pediatric disease, the rubella retinopathy may have the potential to cause neovascular maculopathy.

Child↗
PubMed2000

A high association with cone dystrophy in Fundus albipunctatus caused by mutations of the RDH5 gene.

PURPOSE: To analyze the RDH5 gene in patients with fundus albipunctatus with and without cone dystrophy and to determine whether the disease is stationary or progressive and whether the cone dystrophy is a part of fundus albipunctatus or a separate disease. METHODS: Fourteen patients from 12 separate Japanese families with fundus albipunctatus were examined. Six of the patients from 6 families also had a cone dystrophy. Genomic DNA was extracted from leukocytes of the peripheral blood, and exons 2, 3, 4, and 5 of the RDH5 gene were amplified by polymerase chain reaction and were directly sequenced. A complete ophthalmic examination was performed including best-corrected visual acuity, slit-lamp examination, indirect ophthalmoscopy, fundus photography, and electroretinography. RESULTS: In all the patients, either a homozygous mutation or compound heterozygous mutations in the RDH5 gene were identified. The identified mutations were nucleotide position (nt) 103 G to A (Gly35Ser), nt 319 G to C (Gly107Arg), nt 394 G to A (Val132Met), nt 719 G insertion (frame shift), nt 839 G to A (Arg280His), nt 841 T to C (Tyr281His), and nt 928 C to GAAG (Leu310 to GluVal). All these mutations except the Arg280His were new. The nt 928 C to GAAG mutation was detected in patients with and without cone dystrophy. Cone dystrophy was most frequently seen in patients over 40 years old. CONCLUSIONS: Fundus albipunctatus either with or without cone dystrophy is caused by mutations of the RDH5 gene. Cone dystrophy is frequently observed in elderly patients with fundus albipunctatus. The conclusion was reached that the mutations of the RDH5 gene caused a progressive cone dystrophy as well as night blindness.

Adolescent↗
PubMed1999

Abnormal focal macular electroretinograms in eyes with idiopathic epimacular membrane.

PURPOSE: To study the functional state of the retina beneath an epimacular membrane by means of focal macular electroretinography. METHODS: Focal macular electroretinograms of 30 consecutive patients (age 25 to 75 years) with unilateral idiopathic epimacular membrane were recorded prospectively. The amplitudes and implicit times of the a and b waves and the oscillatory potentials (O1, O2, O3) recorded from the eye with idiopathic epimacular membrane were compared with those of the normal fellow eye. RESULTS: There was a statistically significant reduction in the amplitude of the a wave (P < .001), the b wave (P < .001), and the oscillatory potentials (O1 + O2 + O3; P < .001) of the affected eyes. The reduction of the b-wave amplitude was significantly greater than that of the a wave, resulting in a lower b/a wave ratio (P = .003) in the affected eyes. The reduction in the amplitude of the oscillatory potentials was significantly greater than that of the other two components (P < .001). The implicit times were significantly prolonged for the a wave (P < .001), the b wave (P = .004), and 03 (P < .001). There was a significant correlation between relative b-wave amplitude (affected/normal fellow eye) and the visual acuity (r = -0.50, P = .007). These findings were similar to those we reported for eyes with aphakic cystoid macular edema. CONCLUSIONS: The focal macular electroretinograms in eyes with epimacular membrane disclosed abnormalities that were similar to those of eyes with cystoid macular edema. This suggests that the epimacular membrane probably induced damage to the neurons in the inner retinal layers. Dysfunction of these neurons is one possible cause of visual impairment in this disease.

Adult↗
PubMed1999

Amplitude increase of the multifocal electroretinogram during light adaptation.

PURPOSE: To determine using the multifocal ERG technique whether there are any regional differences in the increase in the amplitude of cone electroretinograms (ERGs) during light adaptation. METHODS: Multifocal ERGs were recorded with the Visual Evoked Response Imaging System from five normal subjects. Thirty-seven hexagonal stimulus elements and a recording time of 60 seconds were used. After 20 minutes of dark adaptation, multifocal ERGs were repeatedly recorded every 2 minutes over a period of 16 minutes. The amplitudes of the multifocal ERGs at different eccentricities were compared during the 16 minutes of light adaptation. RESULTS: During the 16 minutes of light adaptation, the summed responses of the multifocal ERGs increased in amplitude an average of 36% and 47% for the negative and positive components, respectively. The magnitude of increase was minimal in the central retina at 22% and was significantly larger in the peripheral retina at 58%. The implicit time was slightly increased (<4%) with light adaptation, but there were no regional differences. CONCLUSIONS: The results demonstrated that there are topographic variations in the amplitude increase of cone ERGs during light adaptation. This topographic variation indicates that the mechanism for the increase must be based on known regional differences in the retina.

Adaptation, Ocular↗
PubMed1998

Focal macular electroretinograms before and after successful macular hole surgery.

PURPOSE: To report changes in focal macular electroretinograms before and after successful macular hole surgery and to discuss whether preoperative retinal function can predict postoperative visual acuity. METHODS: In this prospective study, 28 consecutive eyes of 28 patients underwent vitrectomy for stage 2 or 3 full-thickness idiopathic macular hole. Focal macular electroretinograms using a 4-degree stimulus spot were obtained in 24 eyes of 28 patients, and those using a 5-degree stimulus spot were obtained in 24 eyes of 28 patients, to evaluate preoperative and postoperative amplitude and implicit time of the b-wave. Visual acuity was measured preoperatively and postoperatively, and results were translated into logMAR (minimum angle of resolution) values. RESULTS: After successful macular hole closure, the b-wave amplitude increased in 23 of 24 eyes measured with the 4-degree stimulus spot and in 19 of 24 eyes measured with the 5-degree stimulus spot. Postoperative b-wave amplitude recorded with either stimulus spot correlated with postoperative corrected visual acuity. The b-wave implicit time decreased in 15 of 20 eyes measured with the 4-degree spot and in 13 of 23 eyes measured with the 5-degree spot. Preoperative b-wave implicit time measured with the 5-degree stimulus spot correlated significantly (P = .001) with postoperative corrected visual acuity. CONCLUSIONS: Qualitative change (implicit time) is more important than quantitative change (amplitude) in electroretinograms for predicting postoperative corrected visual acuity. The function of the retinal tissue surrounding the hole may affect visual outcome.

Adult↗
PubMed1998

Recording multifocal electroretinogram on and off responses in humans.

PURPOSE: To record the on and off responses of the multifocal photopic electroretinogram (ERG) from the human retina and to explore how each ERG component (a-, b-, and d-waves) changes at different retinal eccentricities. METHODS: Multifocal ERGs were recorded with the visual evoked response imaging system. Sixty-one densely packed stimulus elements were square wave-modulated between stimulus on and stimulus off, according to a binary m-sequence at a rate of 4.7 Hz under a constant background illumination. The ERGs were recorded with a bipolar Burian-Allen bipolar contact lens electrode from five normal subjects. Response densities (amplitude per retinal area) were calculated for five different eccentric rings. RESULTS: The response densities for all components (a-, b-, and d-waves) decreased with increasing retinal eccentricities. The ratio of the d-wave to b-wave amplitudes was minimal in the central retina and increased toward the periphery. The ratio of a-wave to b-wave amplitudes also increased toward the peripheral retina. CONCLUSIONS: These results demonstrate that the on and off responses of the human cone ERGs have different spatial distributions across the human retina, and they suggest a change in the photopic retinal circuitry with increasing retinal eccentricities.

Adult↗
PubMed1998

Effect of glutamate analogues and inhibitory neurotransmitters on the electroretinograms elicited by random sequence stimuli in rabbits.

OBJECTIVE: To study the origin of the different components of the electroretinogram (ERG) elicited by a random binary m-sequence stimulus. METHODS: Electroretinograms were recorded from pigmented rabbits before and after the injection of glutamate analogues (2-amino-4-phosphono-butyric acid [APB; DL form] and cis-2,3-piperidine-dicarboxylic acid [PDA]) and inhibitory neurotransmitters (glycine and gamma-aminobutyric acid [GABA]) to abolish the contribution of different cell types to the ERG. Two types of stimuli were used: conventional full-field stimulation with short- and long-duration flashes and a random binary m-sequence of flashes designed to mimic the pseudorandom binary m-sequence stimulation used in the multifocal ERG technique. RESULTS: The effects of APB and PDA on the first-order kernel of the random ERGs were similar to those on the photopic short-flash ERG. Glycine and GABA minimized the oscillatory potentials (OPs) of the photopic ERGs, and also reduced the amplitude of the positive wave of the first-order kernel slightly but caused a large reduction in the amplitude of the second-order kernel. CONCLUSIONS: The data suggest that the ON and OFF bipolar cells contribute significantly to the photopic short-flash ERG, as previously shown, and to the first-order kernel of the responses elicited by the pseudorandom binary sequence stimuli. The second-order kernel and the OPs receive a strong contribution from the cells of the inner retinal layers.

Aminobutyrates↗
PubMed1997

Focal macular electroretinogram before and after drainage of macular subretinal hemorrhage.

PURPOSE: To record and evaluate change in preoperative and postoperative macular electroretinograms in patients undergoing surgical drainage of macular subretinal hemorrhage. METHODS: Five eyes of five patients with good visual acuity before onset of hemorrhage underwent vitrectomy between 3 and 14 days after developing hemorrhage, with drainage of submacular hemorrhage, using recombinant tissue plasminogen activator. The causes of subretinal hemorrhage were macroaneurysm in three eyes, age-related macular degeneration in one eye, and unknown in one eye. Visual acuity and macular electroretinograms were recorded preoperatively and postoperatively. RESULTS: In all eyes, preoperative electroretinographic response was remarkably reduced or not recordable. Postoperative visual acuity improved, and electroretinographic response recovered to about one half the amplitude of the fellow eye in every eye with a normal fellow eye. CONCLUSIONS: A nearly nonrecordable preoperative response on macular electroretinogram indicates severe dysfunction of the photoreceptors caused by the submacular hemorrhage. A postoperative recovered macular electroretinogram suggests that photoreceptor function is at least partially reversible with surgical intervention, including injection of recombinant tissue plasminogen activator into the subretinal space.

Aged↗
PubMed1997

Recording multifocal electroretinograms with fundus monitoring.

PURPOSE: To record multifocal electroretinograms (ERGs) with simultaneous fundus monitoring. METHODS: An infrared television fundus camera was used to monitor the fundus. A tightly packed array of 19 yellow light-emitting diodes (LEDs) was used as the stimulus source and LEDs were alternated between on and off according to a binary m-sequence at a rate of 75 Hz. The stimulus array subtended approximately 25 degrees of the visual angle. Multifocal ERGs were recorded with a Burian-Allen bipolar contact lens electrode from two normal subjects and a patient with macular dystrophy. RESULTS: When the center of the stimulus was positioned on the fovea, the amplitude of the response was largest at the fovea and decreased toward the peripheral retina; the response pattern corresponded to the spatial distribution of cone cells. When the center of the stimulus was positioned on the optic disc, the response at the optic disc was undetectable. A reliable multifocal ERG was obtained from a patient with macular dystrophy. CONCLUSIONS: This system made it possible to monitor the stimulus on the fundus and to adjust the stimulus to the correct retinal locations with exact focusing. The authors' findings indicate that this method especially can be useful in patients with poor fixation. In addition, the authors' results suggests that the stray light effect in the multifocal stimulus system is minimal if any.

Adult↗