Fundus Albipunctatus Diagnosed in a 9-year-old Female

PURPOSE: We report a case of fundus albipunctatus discovered in a young patient. CASE SUMMARY: A 7.6-year-old female showed numerous small whitish-yellow flecks in the perimacular area and retinal periphery. Dark adapted 0.01 electroretinography (ERG) and dark adapted 3.0 ERG were profoundly reduced. At 26 months after the first visit, the best-corrected visual acuities were 1.0 right eye and 0.9 left eye. There were no pigmented lesions, atrophic lesions, or vascular abnormalities in the retina. Humphrey and Goldmann visual field tests were performed, but neither of the tests revealed any scotomas or other visual field defect. The number and size of characteristic numerous small whitish-yellow retinal flecks seemed almost unchanged. In spectral domain-optical coherence tomography (SD-OCT), the subretinal hyper-reflective lesions spanned the retinal pigment epithelium and the external limiting membrane. ERG showed improved dark adapted responses (dark adapted 0.01 ERG and dark adapted 3.0 ERG) after prolonged dark adaptation (2.5 hours). No family member showed any abnormal findings. CONCLUSIONS: Fundus albipunctatus is a rare disease in Koreans. We report a case diagnosed using fundus photography, SD-OCT, visual field tests, and ERG after prolonged dark adaptation (2.5 hours).

Full-field electroretinogram recorded with skin electrodes in normal adults / Eletrorretinograma de campo total registrado com eletrodos de pele em adultos normais

ABSTRACT Purpose: Alternative recording methods have been tested to allow the electroretinogram (ERG) recording in uncooperative patients and/or patients with palpebral alterations, including recordings with skin electrodes. The purpose of this study was to compare ERG recorded with skin electrodes and well-established microfiber electrodes and to determine normative values of ERG parameters for recording with skin electrodes. Methods: Fifty healthy volunteers (17-26 years; mean 20.63 ± 2.01 years) participated in the study. A gold disk skin electrode was placed on the lower orbital rim of a randomly chosen eye. On the contralateral eye, a microfiber electrode was positioned in the lower conjunctival sac. Gold disc electrodes were positioned at the ipsilateral outer canthus of both eyes acting as reference electrodes for the creation of a potential difference. Two ground electrodes were placed on the lobe of each ear. ERGs were recorded according to the International Society of Clinical Electrophysiology Visual (ISCEV) protocol using the VERIS 5.1.9 system for data acquisition and analysis. Results: Both types of electrodes showed similar wave response morphologies. The implicit time of responses between the two electrodes was comparable. On peak-to-peak amplitude, skin electrode recordings showed an amplitude reduction of 61.4% for rod responses, 61.5% for maximal responses, 46.2% for oscillatory potentials, 57.4% for cone responses, and 54.4% for 30Hz-flicker responses, when compared with microfiber electrode recordings. Based on these findings, normative values for peak-to-peak amplitude and implicit time to be used as a reference for ERGs recorded with skin electrodes were determined. Conclusions: ERGs recorded with skin electrodes presented lower peak-to-peak amplitude compared with microfiber electrodes. However, using appropriate normative values, skin electrodes may be useful for specific target populations such as uncooperative infants and/or patients with ocular surface alterations.

RESUMO Objetivo: O eletrorretinograma de campo total (ERG) em pacientes não colaborativos e/ou com alterações palpebrais pode ser registrado com diferentes métodos de captação de respostas, dentre eles os eletrodos de pele. O objetivo deste estudo foi comparar o eletroretinograma obtido com eletrodos de pele e eletrodos de microfibra, determinando valores normativos para os parâmetros registrados com eletrodos de pele. Métodos: Cinquenta voluntários saudáveis (17-26 anos; média 20,63 ± 2,01) participaram deste estudo. Um eletrodo de cúpula de ouro foi aderido à pele na margem orbital inferior de um dos olhos escolhido ao acaso. No olho contralateral, um eletrodo de microfibra foi posicionado no saco conjuntival inferior. Eletrodos de cúpula de ouro foram posicionados na região lateral de cada olho para a formação da diferença de potencial com o eletrodo ativo. Dois eletrodos terra foram posicionados no lobo de cada orelha. O eletrorretinograma foi registrado de acordo com o protocolo da ISCEV (Sociedade Internacional de Eletrofisiologia Visual), com o sistema VERIS 5.1.9 para aquisição e análise dos registros. Resultados: Os dois tipos de eletrodos apresentaram morfologias de onda similares. O tempo implícito das respostas foi comparável entre os dois tipos de eletrodo. Os registros feitos com eletrodo de pele quando comparados aos registros com eletrodos de microfibra mostraram reduções na amplitude das ondas, de 61,4% para resposta de bastonetes, 61,5% para resposta máxima, 46,2% para potenciais oscilatórios, 57,4% para resposta de cones, e 54,4% para flicker 30Hz. Baseado nestes resultados, foram determinados valores normativos para amplitude e tempo de implícito para ERGs obtidos com eletrodos de pele. Conclusões: ERGs registrados com eletrodos de pele apresentam respostas com amplitudes menores quando comparados aos registrados com eletrodos de microfibra. No entanto, usando valores normativos apropriados, os eletrodos de pele podem ser uma alternativa útil para populações especificas como pacientes não colaborativos e/ou com alterações palpebrais.

Verso e avesso da sombra: tessitura de profanação sensível (pensartecorpo na experiência de bioética e aionética)

Tratou-se de um experimento Mítico-Erótiko no suporte da BioÉtica-AionÉtica-Éticada-Vidapor meio de uma cultura da Skótos (Sombra) em solução abstrato-teóricofilosófica(vide procedimentos em Giorgio Agamben) onde se desenvolveram cepashíbridas de idiopaticidade e de criptogenicidade que foram inoculadas no galo-deSócrates-para-Asclépioem vias de administração da oralidade, do rito, daespiritualidade, da filosofia, das humanidades e das artes (dança-Butô, teatro,performance, música, cinema, pintura, fotografia, literatura epistolar, poética,biográfica) com o propósito de observar uma sintomatologia do Contemporâneo e seuspossíveis efeitos adversos (Contra-Temporâneos) nos corpos da potência, diferença,sensações e afetos. Ao descrever os processos de mutações que se efetivaram nesseprotocolo, constatou-se que o próprio campo da Linguagem empreendeu uma curvaendógena (experiência sobre si mesmo), em dobraduras que resistiram às configuraçõesfixadas para um uso da gramática e/ou da finalidade identitária. Nessa zona limítrofelaboratorialdas variáveis no Pensamento e na Linguagem (Fora), enquanto aSubjetividade e os Saberes dos Modernos espargiram-se nas intensidades da imanência,persistiu uma estrutura expelida da Pólis arcana, uma arké da feiticeira no Sertão,outrora marginal ao tratamento que o Discurso-Verdade recebe na poesia (das Musas) ena filosofia (do Lógos), nos termos da Lei (Nómos) e da Ordem (Kósmos). A análisepara a coleta dos dados restritos ao presente sugere a multiplicidade de novos estudos apartir da intersecção de metodologias de conhecimento tácito em camadas distintas davirtualidade. Por fim, esse trabalho declara conflito de interesses às problemáticas dasua época, atinente às influências dos Pós-Modernos, dos Pós-Estruturalistas e dosContemporâneos no pensamento da Saúde e do Cuidado.

A Mythical-Erotic experiment in BioEthics-AionEthics-Life Ethics as substantiated by aculture of Skotos (Darkness) in an abstract-theoretical-philosophical solution (seeprocedures in Giorgio Agamben) within which hybrid strains of idiopathy andcryptogenicity were developed and inoculated in Socrates‘s Cock-for-Asclepius duringthe process of administration, of orality, of the rite, of spirituality, of philosophy, of thehumanities and of the arts (Butoh dance, theater, performance, music, cinema, painting,photography, epistolary literature, poetics, biography), with the aim of observing asymptomatology of the Contemporary and its possible adverse affects (CounterTemporaries)upon the bodies of potency, difference, sensations and facts. In describingthe processes of mutations that took place within that protocol, it became clear that thefield of Language itself had performedan endogenous curve (experience of oneself) infolds that resisted fixed configurations for grammar and/or identity purposes. Whereas,in this coterminous laboratorial zone of variables in Thought and Language (Outside),Subjectivity and the Knowledge of the Moderns spread throughout the intensities ofimmanence, one structure that had been expelled from the arcane Polis lives on – anarche of witchcraft in the Sertão, once marginal to the treatment that Truth-Discoursegiven to poetry (by the Muses) and to philosophy (by the Logos), in terms of Law(Nomos) and Order (Kósmos). The analysis of data collection restricted to the presentsuggests the multiplicity of new studies based on the intersection of methodologies oftacit knowledge in distinct layers of virtuality. Finally, this thesis declares a conflict ofinterests with the problems of its age, pertaining to the influence of the Postmoderns,the Poststructuralists and the Contemporaries upon Health and Care thinking.

Result of Visual Evoked Potential, Electroretinography and Electrooculography in Normal Subjects Using MonPack 3 System

PURPOSE: We present the results of visual evoked potential (VEP), electroretinography (ERG), and electrooculography (EOG) in normal subjects using the Mon-pack 3 system (Metrovision). METHODS: VEP, ERG, and EOG were obtained in 92 normal eyes. The measurements followed the International Society for Clinical Electrophysiology of Vision (ISCEV) standardization protocol. In VEP, the standard electrode was placed on the forehead and the active electrode was attached on the occiput. In ERG, a 20-minute dark adaptation was performed after mydriasis, and an ERG-jet electrode was used. EOG was measured by attaching an electrode to each medial canthal skin. Each latent period and electric potential was measured with average, standard deviation, median, and 95% confidencenterval (95% CI). RESULTS: The mean P100 latency in pattern VEP was 104.36 ms, and P100 latency in flash VEP was 116.71 ms. For the maximal ERG response, the implicit times of a and b waves were 22.65 ms and 44.58 ms, respectively and the amplitude of a and b waves were 274.09 microv and 489.52 microv, respectively. For the ERG cone response, the implicit time of a and b waves were 18.21 ms and 33.40 ms, respectively, and the amplitude of a and b waves were 35.87 microv and 104.42 microv, respectively. The mean ERG oscillitatory potential was 285.53 microv. The average EOG Arden ratio was 2.54. CONCLUSIONS: VEP, ERG, and EOG results from normal subjects using the Mon-pack 3 system can be applied to the diagnosis of retina and optic nerve disease and basic research.

Specific Spectral Domain Optical Coherence Tomographic Findings of Oguchi Disease

PURPOSE: To report specific spectral domain OCT findings of Oguchi disease diagnosed with fundoscopic examination and electrophysiological study. CASE SUMMARY: A 14-year-old patient visited our clinic with a complaint of night blindness for ten years. Fundoscopic examination showed a golden-yellow fundus reflex. After three hours of dark adaptation, the fundus color returned to normal (Mizuo-Nakamura phenomenon). In full-field ERG, rod b-wave was not detectable. The a-wave amplitude in maximal combined response increased after three hours of dark adaptation, although the b-wave amplitude was similar to the amplitude before dark adaptation, demonstrating a negative waveform. In the spectral domain OCT images of the perifoveal area, no gap between the retinal pigment epithelium and the inner segment/outer segment (IS/OS) junction was detected before prolonged dark adaptation, and a highly reflective band was shown. However, the gap appeared after three hours of dark adaptation, and two highly reflective bands were detected in the OCT images. CONCLUSIONS: The characteristic OCT finding in addition to the specific fundoscopic finding and full-field ERG results may be useful to diagnose Oguchi disease.

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.

Characteristics of dark-adapted and light-adapted oscillatory potentials in human electroretinogram / 南方医科大学学报

<p><b>OBJECTIVE</b>To characterize dark-adapted and light-adapted oscillatory potentials (OPs) in human electroretinogram (EGR) elicited by flashing light stimulation of the same intensity.</p><p><b>METHODS</b>Dark- and light-adapted ERGs of normal eyes were studied. The frequency spectra of the extracted dark-adapted OPs and light-adapted OPs were analyzed by a fast Fourier transform. The peak frequency, latency and total power of the OPs were determined.</p><p><b>RESULTS</b>The averaged peak frequency, latency, and power of the dark-adapted OPs was 125.3∓9.93 Hz, 41.7∓3.56 ms, and 9.25∓5.55 (V·s)(2), as compared with 79.5∓6.79 Hz, 50.8∓5.36 ms, and 3.56∓2.18 (V·s)(2) for light-adapted Ops, respectively, showing significant differences in the parameters between dark- and light-adapted Ops (P<0.001).</p><p><b>CONCLUSIONS</b>Compared with dark-adapted OPs, light-adapted Ops is characterized by a lower peak frequency and a lower power with a prolonged latency.</p>

Adaptações fisiológicas e anatômicas de melissa officinalis L. (Lamiaceae) cultivadas sob malhas termorrefletoras em diferentes intensidades luminosas / Physiological and morphological adaptations of melissa officinalis L. (Lamiaceae) cultivated under thermo-reflector shading nets at different luminous intensities

Objetivou-se, com a realização da pesquisa, avaliar modificações fisiológicas e anatômicas em plantas de melissa, cultivadas sob malhas termorrefletoras (Aluminet®), em diferentes níveis de sombreamento, visando conhecer a plasticidade fenotípica em resposta de adaptação a diferentes quantidades de luz. Os tratamentos foram caracterizados por plantas submetidas a pleno sol e a 20 e 60 por cento de intensidade luminosa, e arranjados conforme o delineamento inteiramente casualizado (DIC). As quantificações de clorofila foram feitas em quatro repetições, as medições das epidermes e parênquimas foram repetidas 15 vezes e utilizou-se 10 repetições para as avaliações das características de cloroplastos e grãos de amido destes. Plantas submetidas a 20 por cento de intensidade luminosa apresentaram maior quantidade de clorofila a e, portanto, maior razão clorofila a/b. Comparativamente, as folhas de melissa a pleno sol e a 60 por cento de luz apresentaram células da epiderme adaxial mais espessas, mas as células da epiderme abaxial mostraram características encontradas em folhas de sombra, ou seja, mais finas. Quanto maior a intensidade luminosa, maior o número de cloroplastos, porém, a pleno sol mostraram-se mais finos e com menor área. Os grãos de amido de plantas cultivadas sob ambientes sombreados tiveram maior área e ocuparam maior parte nos cloroplastos de plantas a 60 por cento de intensidade luminosa. Assim, plantas de melissa, quando submetidas ao sombreamento, tiveram plasticidade fenotípica.

The aim of this study was to evaluate physiological and anatomical modifications in lemon balm plants, cultivated under thermo-reflector nets (Aluminet®) at different levels of shading, in order to understand the phenotypic plasticity in adaptation response to different light quantities. The treatments were characterized by plants subjected to full sun and 20 and 60 percent of luminous intensity, and arranged in completely randomized design (CRD). The quantifications of chlorophylls were done in four replicates, the measurements of epidermis and parenchymas were repeated 15 times and 10 replicates were used to evaluate characteristics of chloroplasts and their starch grains. Plants subjected to 20 percent of luminous intensity showed higher quantity of chlorophyll a and, therefore, higher chlorophyll a/b ratio. Lemon balm leaves under full sun and 60 percent of light showed thicker adaxial epidermis cells, but the abaxial epidermis cells showed characteristics found in shaded leaves, i.e., they were slender. The higher the light intensity, the larger the number of chloroplasts; however, under full sun, they were slender and had smaller area. The starch grains of leaves grown under shaded environments showed larger area and, at 60 percent of luminous intensity, occupied the largest part of chloroplasts. Thus, lemon balm plants, subjected to shading conditions, showed phenotypic plasticity.

Pupil Size in the Normal Korean Population According to Age and Illuminance

PURPOSE: To report the change of pupil sizes according to age and illuminance in the normal Korean population. METHODS: Normal Koreans outpatients who never had a history of ophthalmic disease were examined. The patients consisted of 320 eyes of 160 patients, which were classified into 8 age decades (teenage to 80's) with 40 eyes in each age group. The vertical and horizontal pupil size and area under 4 different illuminances (3,500, 1,200, 500, 5 lux) were measured using the Colvard pupillometer(R) (OASIS Medical, Glendora, CA, USA). RESULTS: The pupil size was significantly decreased as the age increased under each illuminance. The pupil area measured after dark adaptation was 47.30 mm2 in the teenage group, 43.32 mm2 in the 20's group, 41.94 mm2 in the 30's group, 40.98 mm2 in the 40's group, 40.61 mm2 in the 50's group, 38.60 mm2 in the 60's group, 37.78 mm2 in the 70's group and 35.45 mm2 in the 80's group. The decrease in pupil area was statistically significant. CONCLUSIONS: In the normal Korean population, a significant decrease in pupil size and area was observed with aging. The present study results provide good basic data for cataract and presbyopia refractive surgery.

c-Fos Immunoreactivity in the Neurons of the Lateral Geniculate Nucleus in Albino Rats by Light Exposure after Dark Rearing

PURPOSE: To investigate the effect of dark rearing immediately after birth on the maturation of the visual relay neurons in the lateral geniculate nucleus. METHODS: Fifty neonatal rats were used. Neonates of the control groups were raised under a normal light/dark cycle. Neonates of the experiment groups were dark reared and isolated from light during the entire experimental period, then exposed to the sun light for 1 hour before sacrifice. RESULTS: In the control groups, the neurons in the dorsal lateral geniculate nucleus developed normally at each age tested. In the experiment groups, the cytoplasm of the large neurons in the dorsal lateral geniculate nucleus of 2-week-old rats contained small vesicles, and the cytoplasm of the large neurons of 4-week-old rats was converted into a vacuole-like space. Moreover, c-Fos immunoreactivity of the large neurons in the dorsal lateral geniculate nucleus in the experiment groups was significantly increased compared to that of the control groups. CONCLUSIONS: We suppose that the maturation of the neurons in the lateral geniculate nucleus might be influenced by light stimulation during the critical period. Furthermore, c-Fos could be a marker of the functional activity of the visual relay neurons of the lateral geniculate nucleus in albino rats.

Pupil constriction can alter the accuracy of dark room provocative test / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Primary angle-closure glaucoma (PACG) is a major cause of visual morbidity in East Asia. Dark-room provocative test (DRPT) has been used to determine which narrow angles have the risk to develop angle closure. However, the accuracy of DRPT might be altered because that after emerging from the dark room, the configuration of the angle is affected by the light of the slit-lamp and the appositionally closed angle reopens. The aim of this study was to examine the pupillary diameter in different light conditions and use it as a parameter to assess the accuracy of dark-room provocative test.</p><p><b>METHODS</b>Patients with suspected primary angle-closure glaucoma undergoing DRPT were recruited. The anterior chamber angle was examined by anterior segment optical coherence tomography under the following conditions: (1) in standard room illumination; (2) after short-term dark-adaptation and (3) after DRPT. Mean values of pupil size and numbers of appositionally closed angle under different conditions were compared.</p><p><b>RESULTS</b>A total of 47 eyes of 47 patients were analyzed. The pupil size after DRPT was smaller than that after short-term dark-adaptation (P < 0.001) and smaller than that in standard room illumination (P = 0.026). The numbers of appositionally closed angles after short-term dark-adaptation were significantly larger than those after DRPT (P < 0.001). There was no significant difference between the numbers of appositionally closed angles in standard room illumination and after DRPT (P = 0.157).</p><p><b>CONCLUSIONS</b>Constriction of pupil size immediately after prolonged dark room provocative test may lead to change in the angle configuration, which may lead to false negative results. We suggest a modified protocol of recording intraocular pressure immediately after DRPT and performing gonioscopy following short-term dark adaptation to improve the accuracy of angle closure assessment.</p>

New comparative ultrasound biomicroscopic findings between fellow eyes of acute angle closure and glaucomatous eyes with narrow angle / Novos achados comparativos de biomicroscopia ultra-sônica entre olhos contralaterais com fechamento angular agudo e olhos glaucomatosos com ângulo estreito

PURPOSE: To compare morphometric features between fellow acute primary angle-closure (APAC) eyes and glaucomatous or suspect eyes with narrow angle (NA). METHODS: Fellow eyes of 30 patients with unilateral APAC and 30 with NA were evaluated by ultrasound biomicroscopy (UBM) under light and dark conditions. UBM parameters such as anterior chamber depth (ACD), angle opening distance at 250 µm/500 µm from the scleral spur (AOD250/AOD500), trabecular ciliary process distance (TCPD) and iris-lens contact distance (ILCD) were measured in the superior (SQ) and inferior (IQ) quadrants. RESULTS: Significant differences between APAC fellow and NA eyes were found in ACD, P<0.001; AOD250 at SQ and IQ, P<0.001; AOD500 at SQ and IQ, P<0.001; TCPD light, P=0.010 and TCPD dark at SQ, P=0.031; and TCPD light at IQ, P=0.010. Significant differences between light and dark examinations of APAC fellow eyes were found in ILCD (P=0.009) at SQ and ILCD at IQ (P=0.006), and of NA eyes in ILCD at SQ (P=0.047) and ILCD at IQ (P<0.001). CONCLUSIONS: APAC fellow eyes have a more crowded anterior segment and shallower ACD than NA eyes. ILCD decreases in both groups when the illumination conditions change from light to dark.

OBJETIVO: Comparar características morfométricas entre olhos contralaterais com fechamento angular primário agudo (FAPA) e olhos glaucomatosos ou suspeitos com ângulo estreito (AE). MÉTODOS: Olhos contralaterais de 30 pacientes com FAPA unilateral e olhos de 30 pacientes com AE foram avaliados através da biomicroscopia ultra-sônica (BUS) no claro e escuro. Parâmetros da BUS como a profundidade central de câmara anterior (PCA), distância da abertura angular a 250 µm/500 µm do esporão escleral (AOD250/AOD500), distância entre o processo ciliar e o trabeculado (TCPD) e distância do contato iris-cristalino (ILCD) foram medidos nos quadrantes superior (QS) e inferior (QI). RESULTADOS: Diferenças significativas entre olhos contralaterais de FAPA e olhos com AE foram encontradas na PCA, p<0,001; AOD250 no QS e QI, p<0,001; AOD500 no QS e QI, p<0,001; TCPD no claro, p=0,010 e TCPD no escuro no QS, p=0,031; e TCPD no claro no QI, p=0,010. Diferenças significativas entre exames no claro e escuro realizados em olhos contralaterais com FAPA foram encontradas na ILCD (p=0,009) no QS e ILCD no QI (p=0,006), e em olhos com SE na ILCD no QS (p=0,047) e ILCD no QI (p<0,001). CONCLUSÕES: Olhos contralaterais de FAPA apresentam um segmento anterior mais aglomerado e uma PCA menor que olhos com AE. ILCD diminui em ambos os grupos quando as condições de iluminação mudam do claro para o escuro.

The Antimydriatic Effect of Brimonidine 0.15% on the Dark-adapted Pupil in Dark Brown Irides

PURPOSE: To analyze the effect of the daily use of brimonidine tartrate 0.15% on the dark-adapted pupil diameter in dark brown irides. METHODS: Twenty-five healthy volunteers administered brimonidine tartrate 0.15% to their right eyes once daily for 3 weeks. Infrared digital photographs of the pupil were taken before administration and 1 hour and 4 hours after administration after dark adaptation (at <0.1 lux ambient illumination for 5 minutes). The diameters of both pupils were measured on the first day, on administration days 7 and 21, and on washout day 7. RESULTS: Four hours after the first administration, pupils showed a decrease of 0.95+/-0.74 mm, 1.03+/-0.94 mm, 0.61+/-0.85 mm on the first day, administration day 7, and administration day 21, respectively (p<0.01), compared with baseline data. The anti-mydriatic effect of brimonidine was sustained for 3 weeks, but the proportions of the eyes showing a reduction in pupil diameter by 0.5 mm or more were 84%, 76%, 68%, and 52% at 4 hours on the first day, administration days 7 and 21, and washout day 7, respectively. CONCLUSIONS: The anti-mydriatic effect of the daily use of brimonidine 0.15% on dark brown irides in a scotopic condition is maintained during the instillation period but has a tendency to fade over time. This point should be considered when using this compound as a miotic agent.

The determination of dark adaptation time using electroretinography in conscious Miniature Schnauzer dogs

The optimal dark adaptation time of electroretinograms (ERG's) performed on conscious dogs were determined using a commercially available ERG unit with a contact lens electrode and a built-in light source (LED-electrode). The ERG recordings were performed on nine healthy Miniature Schnauzer dogs. The bilateral ERG's at seven different dark adaptation times at an intensity of 2.5 cd.s/m2 was performed. Signal averaging (4 flashes of light stimuli) was adopted to reduce electrophysiologic noise. As the dark adaptation time increased, a significant increase in the mean a-wave amplitudes was observed in comparison to base-line levels up to 10 min (p > 0.05). Thereafter, no significant differences in amplitude occured over the dark adaptation time. Moreover, at this time the mean amplitude was 60.30 +/- 18.47 microV. However, no significant changes were observed for the implicit times of the a-wave. The implicit times and amplitude of the b-wave increased significantly up to 20 min of dark adaptation (p > 0.05). Beyond this time, the mean b-wave amplitudes was 132.92 +/- 17.79 microV. The results of the present study demonstrate that, the optimal dark adaptation time when performing ERG's, should be at least 20 min in conscious Miniature Schnauzer dogs.

Effects of Zinc and Hypothermic Process during the Light and Dark Adaptation of Vertebrate Retina

PURPOSE: The purpose of this study was to clarify the effects of zinc treatment and hypothermia on visual adaptation and visual sensitivity in bullfrogs (Rana catesbeiana), which are poikilothermal animals capable of adjusting quickly to environmental temperature changes. METHODS: The effects of both zinc treatment and hypothermia on visual sensitivity were studied by using electroretinogram (ERG) recording and absorption spectra scanning before and after zinc and TSQ (N-[6-methoxy-8-quinolyl]-p-toluene sulfonamide) treatment, with or without temperature changes. RESULTS: In spite of malnutrition due to hibernation, the optimal zinc concentration effect was obtained at 10-4 M (10-2 M 200 microliter ZnCl2 in 20 microliter Ringer's solution) according to ERG recording. After zinc treatment and hypothermia induction, increments of all ERG components and thresholds were taken by ERG recording. These results showed that both zinc treatment and hypothermia may increase visual sensitivity during visual adaptation. In spectral scans, the absorbance increment due to zinc treatment and hypothermia was shown over the whole spectral range (400~750 nm), and it was especially prominent at alpha-peak (about 500 nm). In addition, there was a decrease in absorption differences between dark adaptation and light adaptation after zinc treatment. Furthermore, according to the visual sensitivity decrement using TSQ as a zinc specific chelator, this visual sensitivity increase was shown to be caused by zinc. CONCLUSIONS: As the results suggest, both zinc treatment and hypothermic effects may improve visual sensitivity by promoting rhodopsin regeneration and inhibiting rhodopsin bleaching induced by light illumination. Zinc may activate the enzyme activity of retinol dehydrogenase and phosphodiesterase, while hypothermic effects may improve precursor transport, which is required for rhodopsin regeneration, by tightening membrane adhesion between retinas and retinal pigment epithelia. In addition, we believe that zinc treatment and hypothermic effects may work synergistically to accelerate visual sensitivity during visual adaptation.

Estudo eletrorretinográfico de visão cromática / Electroretinographic study of chromatic vision

OBJETIVO: O objetivo deste estudo é descrever o traçado eletrorretinográfico no gambá sul-americano (Didelphis aurita) obtido com estímulo cromático de comprimento de onda seletivo. O eletrorretinograma é o registro das variações de voltagem nas células retinianas, desencadeadas por estímulo luminoso. O eletrorretinograma representa a atividade elétrica combinada de diferentes células, e sofre variações dependendo da fisiologia retiniana e do método de exame. MÉTODOS: Foram registrados os eletrorretinogramas de seis animais em adaptação ao escuro utilizando filtros cromáticos Kodak Wratten®, e registrada a sensibilidade espectral para comprimentos de onda específicos nas faixas de cores do azul, verde, amarelo, laranja e vermelho. RESULTADOS: Os resultados eletrorretinográficos mais consistentes foram obtidos quando o animal foi estimulado por faixas espectrais seletivas, ao invés de luz branca; e são consistentes com a curva de absorbância das opsinas descritas em fotorreceptores de marsupiais. Estudos prévios sugeriram a tricromacia dos marsupiais por microespectrofotometria de opsinas e imuno-histoquímica de retina. Esse fundamento morfológico não tinha demonstração fisiológica eletrorretinográfica, até este estudo. CONCLUSÃO: O gambá sul-americano tem se mostrado interessante como animal experimental no estudo comparativo da fisiologia visual em mamíferos, especialmente no estudo filogenético da visão cromática. Os marsupiais apresentam um modelo retiniano que superpõe os sistemas fotópico e escotópico; e o gênero Didelphis conserva características encontradas em fósseis do período pleoceno. Portanto, o sistema visual de um marsupial resgata características dos primórdios da evolução dos mamíferos, até o desenvolvimento dos padrões retinianos modernos.

PURPOSE: To describe the electroretinogram of the South-American opossum (Didelphis aurita) obtained by chromatic stimulus of specific wavelengths. The electroretinogram records voltage variations of retinal cells triggered by light stimulation. The electroretinogram represents the combination of electric activity of many different cells and varies according to retinal physiology and examination methods. METHODS: We recorded the electroretinogram of six animals in dark adaptation using chromatic Kodak Wratten® filters, and recorded the spectral sensitivity to specific wavelengths in the spectrum of blue, green, yellow, orange and red light bands. RESULTS: The most consistent electrorretinographic results were obtained when the animals were stimulated by selective spectral bands instead of white light. These results are consistent with the absorbance curve of the opsins described in marsupial photoreceptors. Previous studies using microspectrophotometry of opsins and retinal immunohistochemistry suggested marsupial trichromacy. This morphologic knowledge has not before been physiologically demonstrated by electroretinographic methods. CONCLUSION: The South-American opossum has proven to be an interesting experimental animal for comparative visual physiology studies among other mammals, especially studies on phylogenetic of chromatic vision. The opossum represents a retinal model that superimposes both the photopic and scotopic systems; and the Didelphis genus shows few changes when compared to the fossils of the Pleocene period. Therefore the marsupial's visual system retrieves characteristics from ancient mammal evolution to the retinal patterns found in modern mammals.

[Three cases of benign flecked retina syndrome]

To present 3 rare cases of benign flecked retina syndrome. A 19-year-old female patient presented with fundus albipunctatus appearance in fundoscopy without night blindness and normal dark adaptation time on electeroretinography [ERG]. After 9years of follow up, no change in visual acuity, ERG, or other ophthalmologic examination was seen. Two members of her family had the same condition. Benign flecked retina syndrome presents with fundus abnormalities similar to fundus albipunctatus but without night blindness and normal dark adaptation time and any without any changes in vision or ERG

Study of Blue and Red Flash in Dark-Adapted Electroretinogram

PURPOSE: To investigate the characteristics of the waveform generated by blue and red light stimulations in a dark-adapted electroretinogram (ERG) and those of cone responses in the dark-adapted condition. METHODS: The study subjects were 52 persons (88 eyes) with no previous medical history. The author recorded b-waves (rod response) with red light stimulation and the x-waves (dark-adapted cone response) that appeared before the b-waves. The author also recorded b-waves with blue light stimulation, which had the same amplitude as the b-waves from the red light stimulation. The differences with respect to age and gender were studied. Waveforms of the dark-adapted cone ERGs were recorded by using a digital subtraction technique. RESULTS: The x-wave always appeared before the b-wave with 0 dB (2.4 cd.s/m2) red stimulation. With blue stimulation, a b-wave equivalent to the b-wave stimulated with the red light of 0 dB intensity appeared at an average of -14.57 dB. The implicit time for the b-wave was delayed significantly for the male group. There were no significant differences between different age groups. The dark-adapted cone ERG demonstrated the waveform of a negative response followed by a series of oscillatory potentials (OPs) and a positive response. CONCLUSIONS: The cone responses were followed by the rod responses with red light stimulation of 0 dB in the dark-adapted ERG. The waveforms of the cone ERGs were obtained in dark adaptation with red and blue light stimulation.

Wheel-running and rest activity pattern interaction in two octodontids (Octodon degus, Octodon bridgesi)

Wheel-running and other non-photic stimuli influence the rest-activity pattern of diurnal and nocturnal mammals. A day to night inversion of phase preference of activity was described among Octodon degus, when exposed to ad-libitum wheel running. We have studied the rest-activity pattern response in presence of ad libitum wheel-running in wild-captured male individuals from two species of genus Octodon: O. degus (n=9, crepuscular-diurnal) and O. bridgesi (n=3, nocturnal). After two months of habituation to laboratory conditions, recordings were performed in isolation chambers under a 12:12 light-dark schedule with or without access to a running wheel. Actograms were constructed from data obtained by an automated acquisition system. O. bridgesi were also recorded under constant darkness, with or without access to wheel-running. Entrained to the light-dark schedule, a crepuscular pattern of activity was evident for O. degus, whereas O. bridgesi displayed a robust nocturnal chronotype. The activity of O. degus observed during the dark phase was enhanced when wheel-running was allowed. No significant change in phase preference was observed for O. bridgesi when wheel-running was allowed. A lengthening of endogenous period was observed in O. bridgesi after wheel-running exposure under constant darkness. Nocturnal and diurnal octodontids exhibit different masking responses to wheel-running.

Change of Pupil Diameter after Cataract Surgery or After-Cataract Surgery

PURPOSE: To investigate the change of pupil diameter following cataract surgery or after-cataract surgery and the dependence of this change on the opacity at photopic and scotopic adaptation. METHODS: Thirty-five eyes with cataract and 32 eyes with after-cataract were evaluated prospectively. The pupil diameter was measured at 220 lux (photopic) and 0.05 lux (scotopic) using a pupillometer. Cataract patients were examined preoperatively, and at 1 week and 2 months postoperatively, and after-cataract patients were examined preoperatively, and at 1 week postoperatively. The lens opacity was classified as opacity degree and the after-cataract was divided into pearl and fibrosis type. RESULTS: Pupil diameter of cataract patients was reduced after surgery at photopic and scotopic adaptation (p<0.05). The pupil diameter of eyes with severe opacity degree was 4.3 +/- 1.1 mm and 5.0 +/- 1.1 mm at photopic and scotopic adaptation, respectively, and was larger than eyes with mild opacity degree (3.9 +/- 1.1 mm and 4.5 +/- 1.1 mm, respectively, p<0.05). At photopic and scotopic adaptation, pupil diameter of after-cataract patients was reduced by Nd: Yag laser (p<0.05). The pupil diameter of eyes with fibrosis type, 4.6 +/- 1.0 mm, was significantly smaller than that of eyes with pearls type (5.1 +/- 1.1 mm, p<0.05). CONCLUSIONS: The pupil diameter of eyes with severe opacity degree was larger that of eyes with mild opacity degree. In after-cataract patients, pupil diameter was significant different depending on opacification type at scotopic adaptation and it was reduced after Nd: Yag laser.