Measuring higher order optical aberrations of the human eye: techniques and applications

In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia) and higher order aberrations (coma, spherical aberration, etc.). We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS) sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE) of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.

Quimiluminescência orgânica: alguns experimentos de demonstração para a sala de aula

The generation of "cold light", visible to the human eye, by chemical reactions has attracted the attention of the scientific community since the beginning of this century. Besides the academic interest in the elucidation of the mechanisms of excited state formations, many chemiluminescence reactions have found widespread analytical applications. Moreover, the phenomenon of chemiluminescence can also be used as a tool in undergraduate and college teaching. In this article, we describe several known chemiluminescence demonstrations, which are suitable for school teaching. The main objective of this work is to produce didactic material in Portuguese to stimulate Brazilian secondary and high school teachers to use these experiments in the classroom. The demonstrations include singlet oxygen emission, the luminol reaction, oscillating chemiluminescence and the peroxyoxalate reaction.

Pathology and first report of natural infections of the eye trematode Philophthalmus lachrymosus Braun, 1902 (Digenea, Philophthalmidae) in a non-human mammalian host

The avian eye trematode Philophthalmus lachrymosus Braun, 1902 is for the first time referred naturally occurring in a non-human mammalian host. Previously, natural infections with P. lachrymosus and other species of Philophthalmus have been occasionally reported from man, with few data on experimental infections of non-human mammals. Results presented here are related to the report of two cases of philophthalmosis due to natural infections of wild Brazilian capybaras, Hydrochaeris hydrochaeris L., 1766 with P. lachrymosus and associated pathology. Clinical signs, gross and microscopic lesions as well as new morphometric data on the parasite are presented.

Human ocular sparganosis in southern Brazil

We report the first case of human ocular sparganosis in the state of Santa Catarina, southern Brazil. A young female patient presented with three periocular moveable inflammatory masses in her right eye, during two years. By surgical excisional biopsy, a helminth larval stage was removed and identified as sparganum. Clinical, laboratory and epidemiological data on this parasite are presented.

Effects of submaximal exercise with water ingestion on intraocular pressure in healthy human males

The effects of exercise and water replacement on intraocular pressure (IOP) have not been well established. Furthermore, it is not known whether the temperature of the fluid ingested influences the IOP response. In the present study we determined the effect of water ingestion at three temperatures (10, 24 and 38ºC; 600 ml 15 min before and 240 ml 15, 30 and 45 min after the beginning of each experimental session) on the IOP of six healthy male volunteers (age = 24.0 ± 3.5 years, weight = 67.0 ± 4.8 kg, peak oxygen uptake (VO2peak) = 47.8 ± 9.1 ml kg-1 min-1). The subjects exercised until exhaustion on a cycle ergometer at a 60% VO2peak in a thermoneutral environment. IOP was measured before and after exercise and during recovery (15, 30 and 45 min) using the applanation tonometry method. Skin and rectal temperatures, heart rate and oxygen uptake were measured continuously. IOP was similar for the right eye and the left eye and increased post-water ingestion under both exercising and resting conditions (P<0.05) but did not differ between resting and exercising situations, or between the three water temperatures. Time to exhaustion was not affected by the different water temperatures. Rectal temperature, hydration status, heart rate, oxygen uptake, carbon dioxide extraction and lactate concentration were increased by exercise but were not affected by water temperature. We conclude that IOP was not affected by exercise and that water ingestion increased IOP as expected, regardless of water temperature.

Pharmacology of human experimental anxiety

This review covers the effect of drugs affecting anxiety using four psychological procedures for inducing experimental anxiety applied to healthy volunteers and patients with anxiety disorders. The first is aversive conditioning of the skin conductance responses to tones. The second is simulated public speaking, which consists of speaking in front of a video camera, with anxiety being measured with psychometric scales. The third is the Stroop Color-Word test, in which words naming colors are painted in the same or in a different shade, the incongruence generating a cognitive conflict. The last test is a human version of a thoroughly studied animal model of anxiety, fear-potentiated startle, in which the eye-blink reflex to a loud noise is recorded. The evidence reviewed led to the conclusion that the aversive conditioning and potentiated startle tests are based on classical conditioning of anticipatory anxiety. Their sensitivity to benzodiazepine anxiolytics suggests that these models generate an emotional state related to generalized anxiety disorder. On the other hand, the increase in anxiety determined by simulated public speaking is resistant to benzodiazepines and sensitive to drugs affecting serotonergic neurotransmission. This pharmacological profile, together with epidemiological evidence indicating its widespread prevalence, suggests that the emotional state generated by public speaking represents a species-specific response that may be related to social phobia and panic disorder. Because of scant pharmacological data, the status of the Stroop Color-Word test remains uncertain. In spite of ethical and economic constraints, human experimental anxiety constitutes a valuable tool for the study of the pathophysiology of anxiety disorders.

Uprootedness and the protection of migrants in the International Law of Human Rights

The article attempt to demonstrate the evolution of international law in connected to the subject of the forced immigrants'. The author supported by several texts, cases and resolutions of the regional level, through interamerican court and European court, and the global level, through the international court. It's shown the evolution that occurred in international law in millennium turn over, which recognize the immigrants' rights. However, it's stressed the necessity of the development of those laws connected to the theme e the recognition, from the States; the importance of law's that effort to ensure the respect to human rights relative to the immigrants and their families.

Human Rights promotion in Serbia: a difficult task for the European Union

This article explores the role of the European Union in the human rights protection, implementation and promotion in Serbia. It is clear that the EU demands on democratisation in the region of Western Balkans are crucial to achieve the respect for human rights. The human rights standards as part of the conditionality criteria of the EU is a clear message towards the countries aspiring membership. However, Serbia progress in the field has been difficult due to several internal constraints. This paper aims to uncover the democratisation process of Serbia on its path towards the EU, and its progress (or not) regarding human rights protection and implementation.

Economic sanctions and human rights: an analysis of competing enforcement strategies in Latin America

This article addresses the consequences of economic sanctions for the protection of human rights in Latin America. The literature on sanctions and compliance informs three hypotheses, which investigate the relationship between sanctions and the level of rights protection in two groups of countries: those that were targeted by sanctions and those that were not. Using data from the Political Terror Scale (PTS) and from Freedom House, I find empirical evidence that sanctions do improve the level of protection in countries that were not targeted. This finding can be explained by the deterrent effect attributed to sanctions by the compliance literature, broadly interpreted. The presence of economic sanctions in a given year increases the probability of observing better human rights practices by almost 50%. These results hold for the 12 Latin American countries that were not subject to economic sanctions for the period 1976-2004.