Trataka and cognition: A systematic review with a proposed neurophysiological mechanism

Traditional references of Trataka

Trataka, a fundamental yogic technique of concentrated gazing, originates from traditional Hatha Yoga scriptures, including the Hatha Yoga Pradipika and Gheranda Samhita.^[10] These scriptures describe Trataka as one of the six Shatkarmas (purificatory practices) aimed at cleansing both the body and mind. According to the Hatha Yoga Pradipika (ch: 2, v. 32), this practice is stated to eliminate various eye disorders, relieve fatigue, and get rid of lethargy. Similarly, the Gheranda Samhita (ch: 1, v. 53 and 54) mentions that through consistent practice of Trataka, one may attain Shambhavi Mudra, overcome visual impairments, and develop an enhanced inner perception.

Given its structured nature, Trataka can be examined through the lens of visual neurophysiology and cognitive processing, offering insights into its hypothesized role in enhancing and refining cognitive function.

Study design

This study was designed as a systematic review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Cochrane handbook guidelines, focusing on Trataka practices and their underlying physiological mechanisms.

Inclusion criteria

The inclusion criteria for the systematic review included only RCTs published between 2014 and 2024 (representing the contemporary phase of empirical Trataka research) in peer-reviewed journals, focusing on the intervention of Trataka. Eligible studies were required to mention the underlying mechanisms (to propose a neurophysiological framework linking sustained visual fixation to cognitive enhancement and autonomic regulation) the effects of Trataka on cognitive function. Restricting the review to RCTs was consistent with the Cochrane Handbook for Systematic Reviews of Interventions, which prioritizes RCTs for establishing causal and mechanistic relationships.^[11]

Exclusion criteria

Studies with randomized crossover designs, pre–post experimental designs (to avoid potential carryover and learning effects that may confound cognitive outcomes) or comparative studies (to prevent bias from non-equivalent controls.), or, as well as systematic reviews, meta-analyses, narrative reviews, research protocols, comments, case series, follow-up studies of previous research, and dissertations were excluded from the review. In addition, studies without full text, those that did not investigate the underlying mechanisms of Trataka, were also excluded.

Search strategy and study selection

A systematic literature search was conducted across three major databases, PubMed, Science Direct, and the Cochrane Library (with cochrane covering cochrane central register of controlled trials [CENTRAL]) to capture studies related to Trataka, published between 2014 and 2024. The EMBASE was not searched due to access constraints. The search strategy was formulated using a broad set of synonymous terms to maximize the retrieval of relevant records. In PubMed, the following search string was used in the “All Fields” option [Figure 1]:

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Figure 1:

Preferred Reporting Items for Systematic Reviews and Meta-analyses flowchart. RCT: Randomized controlled trial

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(“Trataka” OR “yogic visual concentration” OR “yogic gazing” OR “yogic candle gazing” OR “yogic flame gazing” OR “yogic visual fixation” OR “yogic concentration” OR “yogic eye cleansing” OR “trataka kriya” OR “yogic ocular exercise” OR “yogic ocular cleansing” OR “yogic visual cleansing exercise” OR “yogic intense gazing”). Out of 61 records identified from PubMed/Medline (22), Cochrane Library (16), and Science Direct (23), 5 duplicates were removed, leaving 56 abstracts for screening. After excluding 31 records based on abstract review, 25 full-text articles were assessed, and 22 were excluded for following reasons: full Text Unavailability (n = 9), do not address the mechanism of interest (n = 6), unsuitable study designs; Self as control study (n = 3), Comparative (n = 2), Pre-post (n = 2). Ultimately, 3 RCTs met the inclusion criteria and were included in the systematic review. Two reviewers independently screened titles, abstracts, and full texts against eligibility criteria, and disagreements were resolved through discussion and consensus to ensure selection reliability.

Risk of bias assessment

Neuro-ocular integration: The eye-brain connection

Trataka and cognition

Emerging research indicates the possibility that the low-intensity light used in Trataka may have an impact on cognitive functions through intrinsically photosensitive retinal ganglion cells (ipRGC).^[12] These specialized retinal cells are sensitive to light exposure and relay signals to brain areas beyond the visual system, including the PFC, amygdala, and hippocampus, regions crucial for emotional regulation and memory processing [Figure 2].^[13] By possibly stimulating ipRGCs, Trataka could contribute to improved cognitive clarity, potentially mitigating mental fog and supporting sustained attention.

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Figure 2:

Neural and cognitive mechanisms of trataka on attention, memory, and emotional regulation. FEF: Frontal eye field, SC: Superior colliculus, DMN: Default mode network.

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This activation is supported by studies on Trataka, demonstrating significant improvements in tasks like the Corsi-block tapping task and Stroop Color-Word Test.^[14] These findings suggest that Trataka strengthens the functional connectivity within the PFC and its associated neural networks, thereby enhancing cognitive control and flexibility.

Saccadic eye movement in visual processing and cognitive function

Saccadic eye movements are rapid, ballistic shifts in gaze that allow the visual system to efficiently scan the environment and integrate sensory information.^[15] These micro-adjustments occur reflexively, helping the brain construct a coherent perceptual field. However, voluntary modulation of saccades, as practiced in Trataka, may introduce a distinct cognitive and neurophysiological challenge, one that has the potential to strengthen attentional stability, neural plasticity, and cognitive control.^[16]

By imposing sustained voluntary fixation (30–60 s), Trataka is hypothesized to minimize spontaneous saccades and reinforces attentional control mechanisms, primarily mediated by the frontal eye field (FEF) and SC.^[17,18] The FEF, a key structure within the dorsal attention network (DAN), plays a central role in cognitive stability, impulse regulation, and working memory.^[19] Engaging this region through prolonged visual fixation may enhance top-down cognitive control, possibly contributing to sustained concentration, greater task persistence, and improved executive function.^[20] Simultaneously, the superior colliculus (SC), a midbrain structure responsible for integrating sensory and motor signals for gaze coordination, may undergo functional modulation, potentially leading to enhanced perceptual stability and greater visual processing efficiency.^[21] The proposed interactions between oculomotor control, attentional stability, and higher cognitive processing suggest that Trataka holds promise as a cognitive training practice.

In addition to its potential role in refining attentional stability, Trataka is hypothesized to enhance neuroplasticity within the cortical-subcortical loop, a network comprising the visual cortex, thalamus, hippocampus, and basal ganglia. The thalamus, specifically the pulvinar nucleus, plays a crucial role in regulating attentional shifts and visual signal transmission.^[22] Trataka-induced fixation may facilitate thalamic filtering, leading to greater sensory precision and reduced distractibility.^[23] The hippocampus, a structure implicated in memory encoding and consolidation, is functionally linked to both visual processing and attentional control, and may also be influenced by Trataka.^[24] The prolonged concentration and focused gaze required in practice could potentially strengthen hippocampal neuroplasticity, thereby supporting improvements in memory retention, spatial learning, and cognitive resilience.^[25,26]

DMN modulation

Another possible neural mechanism influenced by Trataka is the DMN, a network associated with mind-wandering, self-referential thought, and mental distraction.^[27] Excessive activation of the DMN is implicated in attention disorders, anxiety, and depression, often contributing to reduced task-specific engagement.^[28,29] Research indicates that focused-attention meditation and gaze fixation practices can effectively downregulate DMN hyperactivity, redirecting neural engagement toward goal-directed cognitive processes.^[30] By reducing the brain’s tendency for spontaneous mental drift, Trataka may cultivate enhanced present-moment awareness, cognitive clarity, and emotional regulation.^[31] This mechanism is particularly relevant for individuals with attention deficit hyperactivity disorder, generalized anxiety disorder, and age-related cognitive decline, as it offers a structured method for cognitive control and emotional stability.

Taken together, these mechanisms suggest that Trataka serves as an integrative cognitive training tool, with potential applications in neurological rehabilitation, attention training, and cognitive longevity. Empirical findings further support this hypothesis, demonstrating improvements in anxiety and cognitive function, including working memory, attentional control, and executive processing following Trataka practice.^[14,32-35]

This review, while underscoring the potential benefits of Trataka on cognition and autonomic regulation, acknowledges certain limitations. The first included studies were characterized by small sample sizes (ranging from n = 55 to n = 120), which substantially limit statistical power and the ability to detect clinically meaningful effects. Small samples increase the risk of Type II error and reduce the precision of effect estimates, constraining the generalizability of findings to broader populations. Second, the variation in their Trataka protocols, such as differences in the duration, and intervention length, which may limit the comparability of results. Third, methodological constraints, including the impracticality of participant blinding and limited assessor blinding, are inherent to behavioral interventions like Trataka. PEDro evaluations reflected these challenges, with lower scores primarily related to blinding and allocation concealment, suggesting moderate rather than high methodology quality. Nevertheless, potential bias was mitigated by including only RCTs, ensuring baseline comparability, and employing objective cognitive and physiological measures, consistent with consolidated standards of reporting trials (CONSORT) and Cochrane recommendations for non-pharmacologic interventions. Additionally, the review itself was constrained by the availability of RCTs, resulting in a narrow evidence base and limiting broader generalizability. A quantitative meta-analysis was not performed due to (1) very few studies and (2) dissimilar interventions/outcomes. This was to ensure the validity of our conclusions. We emphasize that our aim was a rigorous narrative synthesis to lay the groundwork for future meta-analyses when more trials are available. Despite these challenges, the synthesis highlights promising directions and provides a foundational understanding, encouraging more rigorous and standardized research in the future.

Future implications

By demonstrating that Trataka reliably enhances cognition and autonomic regulation across children, adults, and the elderly and for the first time, mapping these effects onto specific oculomotor and neural circuits, this review lays critical groundwork for addressing the universal challenge of cognitive decline. As the prevalence of MCI and related disorders rises in all age groups, the mechanistic model we propose (involving ipRGC activation, fronto-collicular attentional pathways, thalamic filtering, hippocampal plasticity, and DMN modulation) offers clear biomarkers and targets for future trials. Standardized Trataka protocols can be integrated into preventive and rehabilitative programs, from school-based attention training to geriatric cognitive clinics, requiring minimal resources and training. At the policy level, recognizing Trataka in national guidelines for cognitive health would support its inclusion in public health initiatives and insurance coverage, ensuring equitable access. Finally, our mechanistic insights direct future research toward quantifiable outcomes (e.g., electroencephalogram theta coherence, functional magnetic resonance imaging connectivity, heart rate variability indices), expediting the translation of Trataka from traditional practice to a validated, scalable intervention.