ABSTRACT
PURPOSE: This study assesses the effect of pleoptic treatment on the stability of visual fixation in children and adolescents with amblyopia of various degrees. MATERIAL AND METHODS: The effect of the treatment in 35 children (35 eyes) with amblyopia of various degrees was evaluated using the MP-1 Microperimeter. The stability was determined by two criteria - number of fixation point hits in the 2° zone and the width of the field of fixation. Children underwent a standard course of treatment. RESULTS: There was an improvement in the stability of visual fixation after treatment. The number of fixation point hits in the 2° zone increased from 44.8±4.1% to 52.6±3.8%. At the same time, the width of the field of fixation after treatment decreased from 6.5±0.7° to 5.2±0.5°. Visual acuity with correction in children with amblyopia correlates with the number of fixation point hits in the 2° zone (direct high correlation "+0.7") and width of the field of fixation (inverse high correlation "-0.7") both before and after the treatment. CONCLUSION: Stabilization of visual fixation was observed in patients with amblyopia of varying degrees after the pleoptic treatment.
Subject(s)
Amblyopia , Child , Humans , Adolescent , Amblyopia/diagnosis , Amblyopia/etiology , Amblyopia/therapy , Orthoptics , Fixation, Ocular , Eye , Visual AcuityABSTRACT
Most sources state that pleoptic treatment is ineffective after the age of 14 years. Despite the high level of diagnostic capabilities in modern ophthalmology, unilateral amblyopia is quite often diagnosed in adolescents. This rises the question - should they refuse treatment? To evaluate the impact of treatment on retinal light sensitivity and the state of the patient's visual fixation, a 23-year-old female patient with high degree amblyopia was examined using the MP-1 Microperimeter. Three courses of treatment were carried out to recover (centralize) fixation on the MP-1. In the course of pleoptic treatment, the patient was observed to have a gradual increase in the light sensitivity of the retina from 2.0 dB to 18.5 dB and centralization of visual fixation. Therefore, treatment in adult patients with high degree amblyopia is justified, since the method improves visual functions. The result will be less pronounced and persistent than in patients under the age of 14, but it is still possible to alleviate the patient's condition, which means that if the patient wishes to undergo treatment, it should be carried out.
Subject(s)
Amblyopia , Adult , Female , Adolescent , Humans , Young Adult , Amblyopia/diagnosis , Amblyopia/etiology , Amblyopia/therapy , Visual Acuity , Photophobia , Orthoptics , Fixation, Ocular , Retina/diagnostic imagingABSTRACT
Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the superconducting state and enhanced momentum-relaxing scattering, respectively. Here we report a qualitative deviation from the standard behaviour in doped metallic graphene. We show that Dirac electrons exposed to continuous-wave terahertz (THz) radiation can be thermally decoupled from the lattice, which activates hydrodynamic electron transport. In this regime, the resistance of graphene constrictions experiences a decrease caused by the THz-driven superballistic flow of correlated electrons. We analyse the dependencies of the negative photoresistance on the carrier density, and the radiation power, and show that our superballistic devices operate as sensitive phonon-cooled bolometers and can thus offer, in principle, a picosecond-scale response time. Beyond their fundamental implications, our findings underscore the practicality of electron hydrodynamics in designing ultra-fast THz sensors and electron thermometers.