Asthenopia: Diagnosis, Tatalaksana, Terapi

Asthenopia (kelelahan mata) merupakan sekumpulan gejala berupa permasalahan pada penglihatan (visual), mata (okular), dan muskuloskeletal yang umumnya terjadi hilang timbul. Keluhan ini sering muncul akibat pengaruh penggunaan perangkat digital dalam waktu yang lama terutama lebih dari 6 jam perhari. Penderita asthenopia secara global mencapai 60 juta orang yang didominasi usia muda. Gejala asthenopia yang paling sering dirasakan adalah keluhan mata kering, kesulitan dalam memfokuskan objek, mata tegang, mata lelah, dan sakit kepala. Diagnosis asthenopia dapat dilakukan secara subjektif dengan menggunakan kuesioner standar ataupun secara objektif dengan pemeriksaan lanjutan. Pemeriksaan yang dapat dilakukan berupa pengukuran Critical Flicker-fusion Frequency (CFF), pengukuran frekuensi berkedip, kemampuan akomodasi, serta refleks cahaya dan ukuran pupil yang dapat memberikan gambaran lebih jelas ke arah asthenopia. Tatalaksana dan terapi pada asthenopia diberikan untuk meredakan gejala dan mengatasi penyebabnya seperti terapi untuk mengatasi mata kering, koreksi gangguan refraksi, terapi gangguan akomodasi dan vergensi, dan penggunaan kacamata filter cahaya biru. Walaupun asthenopia terjadi secara hilang timbul, penyakit ini dapat menjadi menetap dan berkembang menimbulkan keluhan permanen. Artikel ini ditulis berdasarkan hasil literature review dari penelitian terkait diagnosis, tatalaksana, dan terapi asthenopia yang sudah dipublikasi. Penulisan artikel ini diharapkan dapat dijadikan acuan dalam menindaklanjuti kasus asthenopia sehingga prevalensi dan insidensinya dapat ditekan.

Real-Time Life-Cycle Monitoring of Composite Structures Using Piezoelectric-Fiber Hybrid Sensor Network

In this paper, an in situ piezoelectric-fiber hybrid sensor network was developed to monitor the life-cycle of carbon fiber-reinforced plastics (CFRPs), from the manufacturing phase to the life in service. The piezoelectric lead-zirconate titanate (PZT) sensors were inserted inside the composite structures during the manufacturing process to monitor important curing parameters, including the storage modulus of resin and the progress of the reaction (POR). The strain that is related to the storage modulus and the state of resin was measured by embedded fiber Bragg grating (FBG) sensors, and the gelation moment identified by the FBG sensors was very close to those determined by dynamic mechanical analysis (DMA) and POR. After curing, experiments were conducted on the fabricated CFRP specimen to investigate the damage identification capability of the embedded piezoelectric sensor network. Furthermore, a modified probability diagnostic imaging (PDI) algorithm with a dynamically adaptive shape factor and fusion frequency was proposed to indicate the damage location in the tested sample and to greatly improve the position precision. The experimental results demonstrated that the average relative distance error (RDE) of the modified PDI method was 68.48% and 46.97% lower than those of the conventional PDI method and the PDI method, respectively, with an averaged shape factor and fusion frequency, indicating the effectiveness and applicability of the proposed damage imaging method. It is obvious that the whole life-cycle of CFRPs can be effectively monitored by the piezoelectric-fiber hybrid sensor network.

Critical Flicker Fusion Frequency: A Narrative Review

This review presents the current knowledge of the usage of critical flicker fusion frequency (CFF) in human and animal model studies. CFF has a wide application in different fields, especially as an indicator of cortical arousal and visual processing. In medicine, CFF may be helpful for diagnostic purposes, for example in epilepsy or minimal hepatic encephalopathy. Given the environmental studies and a limited number of other methods, it is applicable in diving and hyperbaric medicine. Current research also shows the relationship between CFF and other electrophysiological methods, such as electroencephalography. The human eye can detect flicker at 50–90 Hz but reports are showing the possibility to distinguish between steady and modulated light up to 500 Hz. Future research with the use of CFF is needed to better understand its utility and application.

Study of Acute Effect of Caffeine on Cognition among Adults - A Cross Sectional Study from Puducherry, India

BACKGROUND Information processing has substantial role in performing intellectual activities such as thinking, reasoning, remembering, imagining, or learning. Caffeine being a central nervous system (CNS) stimulant, improves mental performance, especially on alertness, attention, concentration and learning depending on the quantity of intake. In the present study, an attempt was made to study the effect of caffeine on cognitive processing in healthy individuals. METHODS This cross-sectional study was conducted on 50 subjects at Mahatma Gandhi Medical College & Research Institute. Montreal cognitive assessment (MoCA) questionnaire was utilized to assess the level of cognition of each subject. Visual reaction time (VRT), auditory reaction time (ART) and critical fusion frequency (CFF) prior and after consumption of 75 mg of caffeine in 200 ml of milk, pre and post reaction time measurement were taken from the subject to address the difference in reaction time. RESULTS Both visual and auditory reaction time were significantly reduced (P < 0.001) after intake of caffeine. The ability of the subject to appreciate the flickering light stimuli to be steady (critical flicker fusion frequency) had significantly improved to 15 % after caffeine intake. CONCLUSIONS Decrease in visual and auditory reaction and increase in critical flicker fusion frequency values indicate that caffeine increases alertness thereby it may enhance performance efficiency in reasoning, planning, judgment, organizing, concept formation, and problem solving. KEY WORDS Visual Reaction Time, Auditory Reaction Time, MoCA

Assessment of Alertness and Cognitive Performance of Closed Circuit Rebreather Divers With the Critical Flicker Fusion Frequency Test in Arctic Diving Conditions

Introduction: Cold water imposes many risks to the diver. These risks include decompression illness, physical and cognitive impairment, and hypothermia. Cognitive impairment can be estimated using a critical flicker fusion frequency (CFFF) test, but this method has only been used in a few studies conducted in an open water environment. We studied the effect of the cold and a helium-containing mixed breathing gas on the cognition of closed circuit rebreather (CCR) divers.Materials and Methods: Twenty-three divers performed an identical dive with controlled trimix gas with a CCR device in an ice-covered quarry. They assessed their thermal comfort at four time points during the dive. In addition, their skin temperature was measured at 5-min intervals throughout the dive. The divers performed the CFFF test before the dive, at target depth, and after the dive.Results: A statistically significant increase of 111.7% in CFFF values was recorded during the dive compared to the pre-dive values (p &lt; 0.0001). The values returned to the baseline after surfacing. There was a significant drop in the divers’ skin temperature of 0.48°C every 10 min during the dive (p &lt; 0.001). The divers’ subjectively assessed thermal comfort also decreased during the dive (p = 0.01).Conclusion: Our findings showed that neither extreme cold water nor helium-containing mixed breathing gas had any influence on the general CFFF profile described in the previous studies from warmer water and where divers used other breathing gases. We hypothesize that cold-water diving and helium-containing breathing gases do not in these diving conditions cause clinically relevant cerebral impairment. Therefore, we conclude that CCR diving in these conditions is safe from the perspective of alertness and cognitive performance.

Effect of abacus training on critical flicker fusion frequency threshold among primary schoolchildren

Objectives: The concept of neuronal plasticity has been considerably studied to know how long-lasting changes are associated with brain’s capacity to be shaped or sculptured by experience. Potential cognitive benefits of abacus training have been proved by various studies indicating it to be a promising tool in improving cognitive abilities including arithmetic abilities, visuospatial and working memory. Critical flicker fusion happens when the individual can no longer differentiate between changing visual stimuli. It can be modulated by behavioural or psychophysical techniques. The objectives of the study were to evaluate the effects of abacus training on critical flicker fusion frequency (CFFF) threshold. Materials and Methods: CFFF threshold (CFFFT) was measured in 60 school students studying third and fourth standard (30 trained in abacus and 30 not trained in abacus) using portable software-based apparatus. Results: The mean scores of abacus trained individuals were significantly higher compared to those who were not trained. Conclusion: Since higher CFFFTs can absorb more visual information, increasing their threshold might lead to cognitive improvement and better academic performance. Abacus trained individuals showed significantly higher critical fusion frequency threshold.