To report the outcome of transcorneal electrical stimulation (TES) of the visual system on long-standing retinal artery occlusion (RAO).
Open labeled, case series.
Two patients with central RAO (15 ...and 33 months respectively) and one with branch RAO (26 months) underwent TES therapy. Subjective and objective ophthalmological evaluations were performed before and after the TES. The ages of the patients were 38, 49, and 63 years. The TES (20 Hz biphasic pulses, 30 minutes, up to 1100 uA) was delivered by a bipolar contact lens electrode once a month for 3 months. Perimetric and/or electrophysiological examinations were performed as outcome measures.
The visual acuity improved by more than 0.2 logMAR units in two cases, and the visual fields were improved in all three cases. The multifocal ERGs which had been reduced in the loci corresponding to the ischemic retinal area were improved after the treatment in two cases. Neither ocular nor systemic adverse effects were observed except for transient superficial keratitis.
TES of the retina can improve retinal function in eyes with long-standing RAOs.
To study the function and morphology of the macula of the eye before and after the removal of unilateral idiopathic epiretinal membrane (ERM).
Focal macular electroretinograms (fmERGs) elicited by a ...15 degrees stimulus were recorded in 37 eyes of 37 patients with a unilateral ERM. The amplitudes of the a- and b-waves and the oscillatory potentials (OPs) were compared with the corresponding waves in the normal fellow eyes before and after removal of the ERM. In 29 eyes followed up for more than 6 months after surgery, the fmERGs and foveal and parafoveal thicknesses, measured by optical coherence tomography (OCT), were evaluated.
Before surgery, the mean amplitudes of all components of the fmERGs were significantly smaller than in the fellow eyes, with the decrease largest for the OPs, followed by the b-waves and then the a-waves. The eyes with less severely reduced a-wave amplitude (>70% of the fellow eyes) had significantly lower b-wave to a-wave (b/a) ratios. After surgery, the amplitudes of the b-wave and OPs were still significantly smaller in the affected eyes. The mean foveal and parafoveal thicknesses were significantly less after surgery; however, the thickness was still more in the affected eyes. The decrease of the OPs remained after surgery and correlated with increased parafoveal thickness (r = -0.460, P = 0.011).
The decreased fmERGs indicate that macular function is impaired in eyes with ERM. The decrease of the b-wave and OPs in the 29 eyes examined after vitrectomy may be due to the still thickened macular retina.
The purpose of this study was to determine the contribution of different types of retinal neurons to the d-wave of the primate electroretinogram using pharmacological agents. NMDA
+
TTX was used to ...suppress inner retinal activity, and APB and PDA to block the activity of the ON- and OFF-pathways, respectively. Results indicated that the inner retinal neurons had a small but certain contribution to the d-wave. The initial rapid phase of the d-wave originates from the activity of the cone OFF-pathway nearly exclusively, and the later slow phase is shaped by the cone photoreceptors. The cone ON-pathway acts in a direction opposite to that of the other components.
The distribution of the electrical current over the retina when electrical pulses are delivered transsclerally has not been clearly determined objectively and quantitatively in humans. The purpose of ...this study was to determine the pattern of electrically evoked neural activity in the monkey retina by using intrinsic signal imaging.
The intrinsic signals of monkey retinas were recorded as changes in the reflectance of infrared light from the retina after transscleral electrical stimulation by DTL electrodes. The effects of changing the stimulus parameters (e.g., intensity, duration, and frequency) of the electrical current, were investigated.
Electrical stimulation evoked a uniform change in the reflectivity across the posterior pole of the retina; that is, the intrinsic signals changed uniformly. A peak of the intrinsic signal was not observed at the fovea. The threshold of the intrinsic signal was not significantly different for the macula, perimacula, and optic disc, and the threshold did not differ under dark- and light-adapted conditions. The strength of the signals increased with longer stimulus durations, and the maximum signals were obtained when the stimulus frequency was between 15 and 20 Hz.
Intrinsic signals of the monkey retina evoked by transscleral electrical stimulation are elicited uniformly across the posterior pole of the fundus and most likely arise from activation of the inner or middle layers of the retina. These functional measurements could serve as a diagnostic tool for mapping the inner retinal activity, by which the site of a lesion can be noninvasively imaged.
The photopic negative response (PhNR) is a negative component of the photopic electroretinogram (ERG) that is observed after the b-wave and is thought to originate mainly from the activity of ...ganglion cells and their axons. The purpose of this study was to determine whether there are subclinical functional changes in the inner retina after macular hole surgery, by recording the PhNR before and after surgery.
In addition to the routine ophthalmic examinations, photopic ERGs were recorded in 16 eyes with an idiopathic macular hole, before and 3 months after surgery. Photopic ERGs were elicited by white Ganzfeld flashes on a rod-suppressing blue background. The amplitude of the PhNR and the a- and b-waves of the photopic ERGs before and after surgery were compared. PhNRs were also recorded in 14 eyes with epiretinal membrane, before and after surgery.
Macular holes were closed and visual acuities were improved without any serious complications in all eyes with a macular hole. The amplitude of the PhNR was significantly reduced after surgery (P < 0.05), whereas the amplitude of the photopic a- and b-waves were not significantly altered. For eyes with an epiretinal membrane, the mean amplitude of the PhNR was slightly decreased after the surgery, but the degree of reduction was only one half of that after macular hole surgery.
These results suggest that there are some functional impairments in the inner retina after macular hole surgery, even though the patients did not show any reduction on subjective visual tests. The PhNR can be a useful clinical test to assess the inner retinal function objectively, before and after vitreoretinal surgery.
To investigate the refractive status and factors associated with myopia by a population-based survey of Japanese adults.
A total of 2168 subjects aged 40 to 79 years, randomly selected from a local ...community, were assessed in a cross-sectional study. The spherical equivalent of the refractive error was calculated and used in a multiple logistic regression analysis to evaluate the relationships between myopia and possible related factors.
The mean (+/- SD) of the spherical equivalent was -0.70 +/- 1.40 diopters (D) in men, and -0.50 +/- 1.44 D in women. Based on +/- 0.5 D cutoff points, the prevalence of myopia, emmetropia, and hypermetropia were 45.7%, 40.8%, and 13.5% in men, and 38.3%, 43.1%, and 18.6% in women, respectively. A 10-year increase in age was associated with reduced risk of myopia men: odds ratio (OR) = 0.53, 95% confidence interval (CI): 0.44-0.62; women: OR = 0.65, 95% CI: 0.54-0.78. In men, myopia was significantly associated with higher education (high school: OR = 1.6, 95% CI: 1.1-2.3; college: OR = 2.0, 95% CI: 1.3-3.1) and management occupations (OR = 1.6, 95% CI: 1.0-2.4). For women, high income (OR = 1.5, 95% CI: 1.1-2.2), and clerical (OR = 1.5, 95% CI: 1.0-2.4) and sales/service occupations (OR = 1.7, 95% CI: 1.1-2.6) were also associated with myopia.
The prevalence of myopia in a Japanese population was similar to that in other Asian surveys but higher than in black or white populations. Our study confirmed a higher prevalence of myopia among younger vs. older populations, and a significant association with education levels and socioeconomic factors.
Purpose
This study examines the impact of cataracts on health-related quality of life (HR-QOL) and health events in the older population.
Methods
The study population consisted of 439 unoperated ...cataract patients aged 60 years or older who visited any of the facilities affiliated with the Cataract Survey Group of the National Hospital Organization of Japan, which has been conducting a prospective multicenter cohort study on cataract patients. HR-QOL of the patients was assessed using the Japanese version of Visual Function Questionnaire-25 (VFQ-25) and the 8-Item Short-Form Health Survey (SF-8). The health condition and health events of the patients were also investigated.
Results
The average age of the 439 patients enrolled (126 men and 313 women) was 73.0 ± 7.1 years. There were 323 patients with comorbidities (73.6%), 81 of whom (23.7%) felt it was hard to visit the hospital owing to their visual impairment. In the previous year, 74 patients (16.9%) had experienced a fall and 14 (3.2%) had been in a traffic accident. Of those, 43.2% and 8.3% respectively answered that the falls and the accident could have been triggered by their visual impairment. When the patients were classified according to visual acuity, most of the VFQ-25 subscale scores declined significantly with decreasing visual acuity, whereas the SF-8 scores showed no significant change.
Conclusions
The participants of this study were patients with unoperated cataract, and thus the decline of HR-QOL was modest. The survey of health events, however, revealed that the visual constraint has a certain impact on the daily lives of the older population.
Purpose: To investigate the relationship between intraocular pressure (IOP) and refractive errors after adjusting for age, central corneal thickness (CCT), and other related factors.
Methods: IOP, ...CCT and refractive errors were measured in the right eyes of 1855 subjects, aged 40–82 years, in a cross‐sectional study design. Subjects were divided into groups by refractive status: hyperopia, emmetropia, mild myopia, moderate myopia, or high myopia. With adjustments for age, CCT, blood pressure, obesity, education, hypertension, diabetes, and smoking status, IOP was estimated for each refractive status using a general linear model.
Results: IOP increased with advancing degrees of myopia, even after adjustment for age, CCT, and other related factors (p = 0.011). Estimated IOP of moderate myopia was significantly higher than that of emmetropia (p = 0.022).
Conclusions: Our results confirm the positive association between IOP and increasing degrees of myopia. This finding would support the hypothesis that the relationship between glaucoma and myopia might be pressure mediated.
PDF
