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.

Acquisition of a Learned Operant and Critical Flicker-Fusion Rate in the Tuatara (Sphenodon spp.)

<p>Scientific investigation of the sensory world and behavior of the tuatara is limited. This study incorporates both ecological and psychological perspectives to test learning and visual perception using a novel operant technique and flicker-fusion rates to measure visual discrimination in tuatara. We posed four main questions: (1) can a reliable method examine learning and visual perception in tuatara?, (2) what is the critical flicker-fusion (CFF) rates for tuatara and how does it relate to motion detection ability?, (3) can stimulus control be transferred to a Y-maze from an open field arena?, and (4) what are the implications for behavioral ecology, conservation, and species welfare? Tuatara (Sphenodon punctatus) were trained using an operant conditioning procedure with food reinforcement to respond to discriminative stimuli (S+) of various flicker-fusion rates, and ignore a non-discriminative stimulus (S-). Tuatara discriminated CFF rates between 2.65-45.61 Hz, but not at 65.09 Hz. The upper threshold between 45.61-65.09 Hz is comparable to other mammalian, avian, and herpetological species. Tuatara demonstrated a learning capacity for acquisition of an operant task as well as cognitive development for learning and memory strategies. Visual discrimination is important to tuatara and may facilitate behavioral responses to many context-dependent ecological processes (i.e., predator/prey/kin recognition, mate selection, environmental discrimination, optimal foraging strategies, and communication). By understanding the importance of visual stimuli, the study provides a better perspective of the tuatara natural sensory world. Additionally, a reliable method was established that can be used for more comprehensive psychophysical experiments to further access visual perception and learning in all reptiles, with the potential to examine other sensory mechanisms such as audition, chemoreception, and tactility.</p>

Acquisition of a Learned Operant and Critical Flicker-Fusion Rate in the Tuatara (Sphenodon spp.)

<p>Scientific investigation of the sensory world and behavior of the tuatara is limited. This study incorporates both ecological and psychological perspectives to test learning and visual perception using a novel operant technique and flicker-fusion rates to measure visual discrimination in tuatara. We posed four main questions: (1) can a reliable method examine learning and visual perception in tuatara?, (2) what is the critical flicker-fusion (CFF) rates for tuatara and how does it relate to motion detection ability?, (3) can stimulus control be transferred to a Y-maze from an open field arena?, and (4) what are the implications for behavioral ecology, conservation, and species welfare? Tuatara (Sphenodon punctatus) were trained using an operant conditioning procedure with food reinforcement to respond to discriminative stimuli (S+) of various flicker-fusion rates, and ignore a non-discriminative stimulus (S-). Tuatara discriminated CFF rates between 2.65-45.61 Hz, but not at 65.09 Hz. The upper threshold between 45.61-65.09 Hz is comparable to other mammalian, avian, and herpetological species. Tuatara demonstrated a learning capacity for acquisition of an operant task as well as cognitive development for learning and memory strategies. Visual discrimination is important to tuatara and may facilitate behavioral responses to many context-dependent ecological processes (i.e., predator/prey/kin recognition, mate selection, environmental discrimination, optimal foraging strategies, and communication). By understanding the importance of visual stimuli, the study provides a better perspective of the tuatara natural sensory world. Additionally, a reliable method was established that can be used for more comprehensive psychophysical experiments to further access visual perception and learning in all reptiles, with the potential to examine other sensory mechanisms such as audition, chemoreception, and tactility.</p>

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.