RESUMO Objetivo: Avaliar comparativamente o limiar de sensibilidade macular da microperimetria e a estabilidade de fixação entre o primeiro (direito) e o segundo (esquerdo) olhos testados de indivíduos normais. Métodos: Trinta pacientes saudáveis foram divididos aleatoriamente em 2 grupos. Os participantes foram submetidos à microperimetria no “fast mode” e no “expert mode” no grupo I e II, respectivamente. Cada participante foi submetido a um único teste e o olho direito foi testado primeiro. Resultados: No grupo I, o limiar médio de sensibilidade macular (± DP) foi de 24,5 ± 2,3 dB e 25,7 ± 1,1 dB nos olhos direito e esquerdo, respectivamente (p=0,0415). No grupo II foi de 26,7 ± 4,5 dB e 27,3 ± 4,0 dB nos olhos direito e esquerdo, respectivamente (p=0,58). Não houve diferença estatisticamente significativa entre os olhos dos dois grupos (p=0,1512). Em relação à estabilidade de fixação (avaliada no grupo microperimetria no “expert mode”), a média das porcentagens dos pontos de fixação dentro do 1 grau central da mácula (P1) ± DP foi de 87,9 ± 11,5% no olho direito e de 93,8 ± 6,6% no olho esquerdo. O teste t pareado não mostrou diferença estatística entre os olhos (p=0,140). O valor médio de P2 ± DP foi de 95,5 ± 4,9% no olho direito e 98,5 ± 2,1% no olho esquerdo. Foi demonstrado um aumento na porcentagem de pontos de fixação no segundo olho testado quando comparado ao primeiro (teste t pareado= 2,364; p=0,034). Houve correlação negativa entre o limiar de sensibilidade macular do olho direito e a duração do exame nos dois grupos (microperimetria no “expert mode”: r=-0,717; p=0,0026; microperimetria no “fast mode”: r=-0,843; p <0,0001). Conclusão: O limiar médio de sensibilidade macular foi maior no segundo olho testado no grupo microperimetria no “fast mode” e foi semelhante nos dois olhos no “expert mode”. Nossos dados sugerem que a compreensão do exame pelo indivíduo pode impactar nos resultados da microperimetria.

ABSTRACT Purpose: To comparatively assess the macular sensitivity threshold of microperimetry and the fixation stability between the first (right) and second (left) tested eye of normal participants. Methods: Thirty healthy patients were randomly assigned to two groups. The participants underwent microperimetry in the fast mode and expert mode in groups I and II, respectively. Each participant underwent a single test and the right eye was tested first. Results: The mean macular sensitivity threshold (± standard deviation [SD]) was 24.5 ± 2.3 dB and 25.7 ± 1.1 dB in the first (right) and second (left) eyes of group I, respectively (p=0.0415) and 26.7 ± 4.5 dB and 27.3 ± 4.0 dB in the first (right) and second (left) eyes of group II, respectively (p=0.58). There was no statistically significant difference between eyes in either group (p=0.1512). Regarding fixation stability (evaluated in the microperimetry expert mode group), the mean ± SD percentage of fixation points within the 1-degree central macula (P1) was 87.9 ± 11.5% in the right eye and 93.8 ± 6.6% in the left eye. The paired t-test did not show a statistically significant difference between eyes (p=0.140). Mean ± SD P2 value was 95.5 ± 4.9% in the right eye and 98.5 ± 2.1% in the left eye. The analysis demonstrated an increase in the percentage of fixation points in the second tested eye compared with the first one (paired t-test= 2.364; p=0.034). There was a negative correlation between the macular sensitivity threshold of the right eye and the duration of the examination for both groups (microperimetry expert mode: r=-0.717; p=0.0026; microperimetry in the fast mode: r=-0.843; p<0.0001). Conclusion: Mean macular sensitivity threshold was higher in the second tested eye in the microperimetry in the fast mode group and was similar in both eyes in the expert mode. Our data suggest that comprehension of the examination by the individual may impact the results of the microperimetry test.

ABSTRACT The island rule suggests that, when mainland animals are isolated on islands, large animals tend to become smaller, while small animals tend to become larger. A small frog in eastern Brazil, Phyllodytes luteolus (Wied-Neuwied, 1824), is widely distributed in association with bromeliads. At the end of the last glaciation, parts of the mainland became islands due to rising sea levels, thereby isolating frog populations on these islands. If the island rule holds, we predicted that frogs on islands would tend to be larger than frogs on the mainland. We compared sizes (weight and length) of 30 randomly selected male frogs from the mainland with 30 from an island in the state of Espírito Santo, Brazil. We also sampled population density on the island and mainland because concurrent with changing sizes, depending on the causal relationship, density may also change. As predicted, island frogs tended to be larger (both in snout-vent length and weight) and were much more abundant. While not specifically addressed in this study, the absence of predators and interspecific competitors may explain both of these trends.

Se estudiaron los anuros que usan las rosetas de 60 bromelias del género Alcantharea, en un afloramiento rocoso del sudeste de Brasil. Se encontraron 153 larvas y 21 adultos de Scinax arduous, 30 adultos de Thoropa miliaris, y dos individuos de Scinax x-signatus, éstos últimos no se incluyeron en los análisis. Las larvas de S. arduous se encontraron en el 35% de las plantas analizadas. Los adultos de S. arduous se presentaron en el 25% de las plantas estudiadas, mientras que los adultos de T. miliaris se encontraron en el 30% de las plantas. Aparentemente, la presencia de ventosas en las patas de S. arduous permite que los individuos de esta especie ocupen la porción central de las bromelias, en tanto que los individuos de T. miliaris, los que carecen de dichas ventosas en sus patas, ocupan las axilas inferiores de las hojas de las bromelias. El número de especies de anuros y la abundancia de individuos fue relativamente baja. Esto puede ser el resultado de la apreciable altitud del área estudiada o por las restricciones impuestas por el ambiente saxícola del área investigada, la cual se caracteriza por presentar elevadas temperaturas y baja humedad durante el día. Ambas especies pueden ser consideradas como consumidores generalistas. Los formícidos constituyeron la principal presa en número, aunque éstos no se registraron en las rosetas de las bromelias. Por su parte, los Blattodea fueron muy comunes dentro de las bromelias, los cuales representaron una presa más importante en peso para las dos especies de anuros. Se puede concluir que ambas especies de anuros forrajean en la parte interna como en la externa de las bromelias. El nicho trófico de S. arduous demostró ser más amplio. Aunque ambas especies de anuros son habitantes comunes del mismo ambiente, éstas presentan una marcada segregación espacial en las bromelias. No obstante, teniendo como base su dieta, las dos especies de anuros disputan territorio por fuera de las bromelias.

Anurans from an inselberg in southeastern Brazil were studied using a sample of sixty tank bromeliads Alcantharea sp. We found 153 tadpoles of S. arduous, 21 adults of S. arduous, 30 adults of T. miliaris, and two individuals of Scinax x-signatus, which were not considered in our analyses. Tadpoles of S. arduous were present in 35% of the analyzed plants. Adults of S. arduous (bromeligeneous) occurred in 25% of analyzed plants, while adults of T. miliaris (bromelicolous) occurred in 30%. Apparently the presence of toe pads in S. arduous allows them to occupy the center portion of bromeliads, while T. miliaris, which do not have pads on their toes, used the base of the plant axils for residency. The number of anuran species and the abundance of individuals found were low. This may be a result of the high altitude of our studied site or a restriction imposed by the saxicolous environment, such as high temperatures and low humidity during the day. Both species can be considered generalist feeders due to their wide variety of ingested prey. Formicidae was their main prey but was absent inside the bromeliads. Blattodea was very common inside the bromeliad axils and represented the most significant prey by weight in both frog species. We can conclude that both anurans forage inside and outside of bromeliads. The trophic niche breadth in S. arduous was larger than in T. miliaris. Even though both species are common inhabitants of the same environment, they demonstrated a marked spatial segregation in the bromeliads. Based on their diet, however, there may be disputes for territory outside of the bromeliads.