Drishti: Integrating Ayurvedic and Modern Perspectives on Vision and Eye Health
REVIEW ARTICLE
Dr. Nandini Miri
PG Scholar, Department of Shalakyatantra, National Institute of Ayurveda, Jaipur, https://orcid.org/0009-0002-2232-3524
Prof. (Dr.) Aparna Sharma
Professor, Department of Shalakyatantra, National Institute of Ayurveda, Jaipur, https://orcid.org/0000-0003-4215-8714
International Journal of Ayurveda360 | Volume 1 | Issue 5|
Journal Details:
- ISSN (ONLINE) : 3048-7390
- ISSN (PRINT) : 3048-7382
- Bimonthly Journal
How to cite this article:
Miri, N., & Sharma, A. (2025). Drishti: Integrating Ayurvedic and Modern Perspectives on Vision and Eye Health. International Journal of Ayurveda360, 1(5), 390–403. https://doi.org/10.63247/3048-7390.vol.1.issue5.13
Publication History:
Submitted:5-March-2025 Revised: 6-April-2025
Accepted: 14-April-2025 Published: 15-April-2025
DOI: 3048-7390.vol.1.issue5.13
DOI Link: https://doi.org/10.63247/3048-7390.vol.1.issue5.13
Address for Correspondence: Dr. Nandini Miri, PG Scholar, Department of Shalakyatantra, National Institute of Ayurveda, Jaipur, Email Id: nandinimiri4@gmail.com
Licensing & Distribution
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ABSTRACT
Introduction:
The Ayurvedic tradition identifies five primary sensory organs, known as Panch Gyanendriya, with the eye (Chakshu) holding paramount importance. In Ayurveda, the concept of Drishti has been extensively discussed, particularly by Acharya Sushruta in his seminal work, the Sushruta Samhita. While Ayurveda offers detailed descriptions of the eye’s anatomy, modern ophthalmology provides a scientific perspective on the layers of the eye, which aligns with certain Ayurvedic concepts.
Methods:
This study analyzes the Ayurvedic texts, primarily focusing on the Sushruta Samhita, and compares them with current ophthalmological knowledge. We explore the six Netra Patala (layers of the eye) as described in Ayurveda and attempt to correlate these layers with anatomical findings in contemporary medical science.
Results:
The study identifies key similarities and differences between Ayurvedic and modern scientific descriptions of the eye. Ayurvedic texts provide a multidimensional view of Drishti, encompassing both anatomical and functional aspects. Contemporary ophthalmology, however, focuses primarily on the structural anatomy of the eye, offering a more streamlined definition of vision.
Discussion:
This study highlights the evolving nature of the Drishti concept within Ayurveda and its interpretation in modern scientific terms. The integration of Ayurvedic insights with current medical knowledge could offer new perspectives on vision and eye health. Further interdisciplinary research is needed to bridge these knowledge systems and enhance the understanding of Drishti.
Keywords: Drishti, Panch Gyanendriya, Acharya Sushruta, Netra Patala, vision, Ayurveda, ophthalmology.
FULL PAPER
INTRODUCTION
Ayurveda, the ancient science of health and well-being, offers a holistic approach to curing diseases and maintaining wellness across all stages of life. It encompasses eight branches, collectively known as Ashtang Ayurveda. Among these, Shalakya Tantra is a specialized branch that focuses on disorders of the supraclavicular region, referred to as Urdhwajatru, which includes the eyes (Netra), ears, nose, throat, head, and neck.
In Ayurvedic texts, the eyes (Netra) are accorded significant importance. Acharya Sushruta, a pioneering figure in Ayurveda, has provided a detailed account of Netra Sharira (the anatomy of the eye) in his work. This description divides the eye into three main components: Mandala (zones), Sandhi (joints), and Patala (layers) [1]. Among the five Mandalas described, the Drishti Mandala, located at the innermost part of the eyeball, is intricately linked to various Drishtigata Rogas (eye disorders).
The term Drishti embodies both the structural and functional aspects of vision. Classical Ayurvedic texts offer a wealth of knowledge on the concept of Drishti, yet it remains a subject of debate and ongoing exploration within Ayurveda. This controversy highlights the need for a comprehensive understanding of its anatomical, physiological, and pathological dimensions, as well as its precise interpretation in Shalakya Tantra. This study aims to explore the various perspectives on Drishti in Ayurvedic and modern literature, striving to provide clarity on this complex and evolving concept.
AIM AND OBJECTIVES
Aim:
To explore and analyze the concept of Drishti as described in Ayurvedic and modern scientific literature, providing a comprehensive understanding of its anatomical, physiological, and pathological dimensions, and addressing its controversial interpretations.
Objectives:
- To study the description of Drishti in Ayurvedic classics, including its structural and functional aspects.
- To correlate the Ayurvedic concept of Drishti with modern anatomical and ophthalmological perspectives.
- To identify and clarify the various meanings and interpretations of Drishti in Shalakya Tantra.
- To understand the role of Drishti in the pathogenesis and management of Drishtigata Rogas (eye disorders) based on Ayurvedic principles.
- To highlight the relevance of Ayurvedic insights in enhancing modern approaches to eye care and treatment.
MATERIALS AND METHODS
Materials:
This study incorporates an extensive review of Ayurvedic texts, including Sushruta Samhita, Caraka Samhita, Ashtang-Hridayam, and Ashtang-Sangraha, alongside relevant modern literature, medical journals, and published research articles. The key insights and relevant points derived from these sources are systematically presented in this study.
Method:
The study adopts a review-based approach, focusing on the comprehensive analysis of the gathered material.
ETYMOLOGY OF DRISHTI
The word Drishti is derived from the root “Drish” (to see) combined with “Ktina Krite Pratyaya,” which collectively translates to “the act of seeing” or “the tool or medium through which one sees.” The term Drishti encompasses a wide array of meanings, such as sight, vision, the act of viewing, the faculty of seeing, or even knowledge and perception. When paired with different qualifiers, the word takes on specific connotations [2].
Overall, the essence of the word Drishti can be summarized into two primary interpretations: first, as the structural component of the eye, and second, as the functional aspect, which involves the act or process of seeing.
- Drishti as a Structural Entity: In Ayurveda, the concept of Nidanas (causes) plays a significant role in understanding the onset of eye diseases. Acharya Sushruta, in Uttartantra, explains that the consumption of certain Nidanas leads to the vitiation of doshas. These imbalanced doshas travel through the Siras (channels), reach the Urdhwabhaga (supraclavicular region), and eventually localize in specific parts of the eye, resulting in various disorders.[3]
- Drishti as Mandala: Acharya Sushruta, while detailing the gross anatomy of the eye, identifies five types of Mandalas (circular zones) in the eyeball: Pakshma, Vartma, Shweta, Krishna, and Drishti. The dimension of the Drishti Mandala is described as 1/7th of the Krishna Mandala (cornea) [4] and 1/9th of Taraka (iris) [5]. Furthermore, Acharya Sushruta mentions the measurement of Drishti as Masurdala matrantu (the size of a lentil cotyledon), while Acharya Sharangdhar refers to it as Masurardha dalonmita (half the size of a lentil cotyledon). The shape of the Drishti is described as Vivarakriti, resembling a round hole or aperture. Its appearance is likened to a firefly (Khadhyota) or a small spark (Visfulingabha).[6] In the chapter on Krishnagata Roga Vigyaniyam, Acharya Sushruta emphasizes the importance of Drishti‘s location regarding corneal ulcers (Savrana Shukra). If the ulcer is near the Drishti or at the center of the cornea (Drishti Mandala), the prognosis is unfavorable. Conversely, if it is distant from the Drishti, the prognosis improves. Some pathological conditions can only be understood in terms of structural aspects and not physiological processes. Acharya Vagbhata also elaborates on the measurements of the Drishti Mandala in proportion to the Krishna Mandala. These dimensions and characteristics highlight Drishti primarily as a structural entity rather than a functional one.
- Drishti as Eyeball: In the Chikitsa Sthana, Acharya Sushruta mentions the application of Srotoanjana (Antimony Sulphide) as part of eye treatment. He describes the white circle, which corresponds to the cornea, and the Krishna (black) area, identified as the Taraka (iris), situated within the white circle. Additionally, he highlights the proportional dimensions of the Drishti in relation to the Krishna Mandala, underscoring the structural harmony within the eyeball. In the management of Nayanabhighata (ocular injury), Acharya Sushruta recommends nourishing therapies like Snigdhadi Drishti Prasada Janana Vidhi [7]. Acharya Charaka suggests the use of Mridu Sweda (gentle fomentation) for Drishti, performed by covering it with Padma and Utpala leaves.[8] During thermal cautery (Agnikarma) on the eyelids, Sushruta advises covering Drishti with a wet gauze, implying the entire eyeball is protected except the treated area. These references indicate that Drishti is considered synonymous with the eyeball. The term “Drishti Visharda,” used by Sushruta for ophthalmologists, also supports this notion. Additionally, commentary in the Sushruta Samhita describes Drishti as encased in an outer coat (Avratam Patalena Akshano Bahyen), with the Vartama Patala (eyelids) serving as protective layers. In the context of Hatadimantha, a complication of Adimantha (glaucoma), Sushruta mentions Drishti Pratikshipan,[9] explained by Acharya Dalhana as the outward protrusion of the eyeball. Symptoms like bulging eyes from increased intraocular pressure further reinforce the identification of Drishti as the eyeball.
- Drishti as Inter-pupillary distance: Acharya Sushruta, in Sutrasthana, describes Drishtyantara as the distance between the Drishti-Mandala, which measures 4 Angula. Among the five Mandalas, the Drishti-Mandala refers to the circular region formed by the pupillary margin. Therefore, Drishtyantara indicates the inter-pupillary distance. In modern terms, the average inter-pupillary distance in an adult male typically ranges from 50 to 75 mm [10].
- Drishti as Cornea: Acharya Sushruta, while discussing the prognosis of Savrana Shukra, noted that involvement of Drishti in the disease indicates an unfavorable prognosis.[11] In modern ophthalmology, this corresponds to cases of corneal ulcers which, if left untreated, can extend into deeper tissues. Damage to the corneal stroma often results in permanent opacity, causing blurred vision, and in severe cases, may lead to complete loss of vision.
- Drishti as Pupil: In Kaphaja Lingnasha, it is noted that the Drishti-Mandala constricts in sunlight and dilates in darkness, indicating its identification as the pupil due to its light-responsive nature. Acharya Sushruta, in the prognosis of Savrana Shukra [12], suggests a better outcome when the condition does not affect the peripheral part of Drishti, understood as the pupil’s outer area. Drishti is described as covered by Bahaya Patala, which, according to Ayurveda, is associated with Tejo-Jala Ashrita and must remain clear for proper vision (Roopa Grahanam). In modern terms, this corresponds to the transparent cornea covering the pupil. The size of Drishti is said to be Masoordala Matra (lentil-sized), approximately 3-4 mm, like the pupil’s diameter (2-4 mm). It is measured as 1/7th of the Krishna-Mandala (corneal circle) and 1/9th of Taraka, identified by Acharya Dalhana as the black part of the eye. The differing proportions suggest that Taraka, or the iris, is larger than the Krishna-Mandala.
- Krishna-mandala (Cornea) × 1/7 = Drishti-mandala (Pupil) (Masoordala Matra)
- Taraka (Iris) × 1/9
Acharya Sushruta has detailed a condition called Gambhirika, which is characterized by changes in Drishti, including its distortion (Viroopa), contraction (Sankuchit), and inward displacement (Abhyantara).[13] Modern science correlates this disorder with Anterior Uveitis. While Drishti is typically Vivarakriti (circular), in Gambhirika, it becomes distorted (Vikrit/Viroopa).
In cases of Iridocyclitis, adhesions form between the pupillary margin and the anterior lens capsule, a condition known as Posterior Synechia, which results in an irregularly shaped pupil, corresponding to the Drishti Viroopa. During Iritis, the iris becomes swollen and its movements sluggish. Although both the sphincter pupillae and dilator pupillae muscles are affected, the stronger sphincter pupillae muscle leads to pupil constriction, accounting for Drishti Sankuchyate. Moreover, the pupillary margin may sink inward (Drishti Abhyantaras Cha) due to posterior synechia.
- Drishti as Lens: The shape and size of Drishti is described in Ayurvedic texts as Masoordala Matra, resembling a lentil cotyledon with a biconvex shape. Interestingly, in modern ophthalmology, the lens also shares this biconvex structure. The lens is suspended by suspensory ligaments attached to the ciliary body, which contains ciliary muscles responsible for its movement. Ayurveda mentions that the Drishti-Mandala constricts in sunlight and dilates in darkness or shadow. Similarly, in modern science, the lens adjusts its thickness based on the intensity of light and the need to focus on distant or nearby objects. For instance, in low light conditions, it is harder to focus on distant objects compared to nearby ones. The ciliary muscles enable the lens to change its shape depending on the visual requirements and the surrounding environment.
- Drishti as Retina and Optic Nerve:
The Netra is composed of five Mandalas: Pakshma, Vartma, Shweta, Krishna, and Drishti [14]. Among these, the last four Mandalas are arranged sequentially from the outermost to the innermost layers. This indicates that the Drishti-Mandala represents the innermost Mandala of the eye.
According to contemporary science, the retina is identified as the innermost layer of the eyeball. Ayurvedic texts describe the appearance of Drishti as resembling a firefly (Khadhyota) or a small spark (Visfulingabha) [15]. In modern ophthalmology, the red reflex serves as a quick and non-invasive diagnostic test to detect opacities in the visual axis. This red reflex refers to the reddish-orange light reflection from the back of the eye (fundus), observed using an ophthalmoscope or retinoscope, which parallels the Ayurvedic depiction of Drishti‘s appearance.
Ayurvedic measurements of the Drishti-Mandala suggest it is 1/7th of the Krishna-Mandala (~11.7 mm horizontally and ~10.6 mm vertically). Calculations indicate that the Drishti Mandala spans approximately 1.51 mm, comparable to the dimensions of the retina’s most sensitive region, the Fovea [16].
Descriptions of diseases in Drishtigata Roga provide further evidence of associating Drishti with the retina:
- A lack of functional cones in the retina leads to Hemeralopia (day blindness), which corresponds to Pittavidagdha Drishti, an Ayurvedic disorder.
- Rod dystrophy or pigmentary retinal atrophy results in Retinitis Pigmentosa, characterized by night blindness (Nyctalopia), also a symptom of Kaphavidagdha Drishti.
- Nakulandhya, a Drishtigata Roga, involves night blindness and correlates with Retinitis Pigmentosa, a retinal disease.
- Haraswajadaya, another Drishtigata Roga, presents symptoms like day blindness and micropsia. Modern science attributes micropsia to macular degeneration, a retinal disorder caused by swelling or bulging of the macula. This association links Haraswajadaya with retinal defects.
Drishti as a Functional Entity: Drishti as Vision
Ayurvedic texts provide clear references suggesting that the term Drishti is often used to denote the process of vision and its functional aspects.
• Acharya Sushruta states that suppressing the natural urge of Kshudha (hunger) results in Krishta cha Drishte (reduced vision).[17] Similarly, Acharya Vagbhata explains that suppressing the urge of Adhovata leads to Drishtyagnivadha. This concept is further elaborated by Acharya Arundatta in his commentary, where he interprets Drishtyagnivadha as Drishte Ragneshcha Vadho, indicating a loss of vision (Nasha of Drishti).
• In the context of Adhimantha Sadhyasadhyata, it is stated that improper dietary and lifestyle habits (Mithya Ahara-Vihara) or inadequate treatment of Adhimantha can result in Drishtihanana, which signifies a loss of vision.[18]
• Additionally, when Visha (toxins) is incorporated into Anjana (medicinal eye applications), it may cause Drishti Vibhram—visual distortion or optical illusion—where an individual perceives objects differently from their actual form. This highlights the critical functional role of Drishti in vision.
• Acharya Caraka has further elaborated that consuming toxin-infused (Visha Yukta) food can disrupt visual processes (Drishti Uprodha) once the food reaches the stomach (Amashaya). This is analogous to cases of methyl alcohol toxicity, where the optic nerve is impaired, leading to optic neuropathy. Moreover, Drishtiprada Varti, as recommended by Acharya Caraka for managing Netra Rogas (ocular disorders), is noted for its potent efficacy, with claims that it could restore vision even to individuals who are blind [19].
• In the Sushruta Samhita, Drishti Visha is described as a symptom of toxicity arising from the sight of a Divya Sarpa (divine snake). This underscores the interpretation of “Drishti” as vision itself [20].
• Furthermore, during the achievement of Yoga Siddhi, an individual attains the ability to perceive minute or invisible entities, referred to as Atindriya Darshan, through Drishti.
• Additionally, the recognition of Arishtasuchak Lakshana (indications of imminent death) via sensory organs (Indriyas), in the absence of Gyan Shakti (cognitive power), suggests that the person is nearing the end of life.
• Acharya Sushruta also explains that congenital blindness (Jatyandha) occurs when Tejodhatu (the essence of light/fire) fails to reach the Drishtibhaga (visual organ). This insight highlights that Drishti serves as the locus of Chakshu Indriya (sense of vision).
• Acharya Sushruta, in the context of Lingnasha, explains that when the doshas responsible for Timir progress into the fourth Patala, it leads to Sarvato Drishti Runnadhi—complete obstruction of vision [21]. Similarly, Acharya Vagbhata, in Aupsargika Lingnasha, refers to Drishti Mushita Darshanam [22], which signifies the loss of visual power in the eyes.
• Additionally, there are numerous references emphasizing the impact of dietary habits (Ahara Sevana) on Drishti, highlighting its significant role in maintaining or impairing vision.
v Acharya Vagbhata highlights that the application of Pinyak (a paste made from sesame seeds, known as Kalka of Tila) results in Drishti Dushana, meaning it adversely affects visual power.
v Conversely, the properties of Mudga (green gram) and food prepared in Ghrita (clarified butter) are said to enhance vision, referred to as Drishti Prasadan [23]. On the other hand, food processed in Taila (oil) is described as Drishtighana, which is detrimental to vision.
v Moreover, products made from incompatible grains (Viruddha Dhanya) are identified as Drishti Pradushaka, impairing visual function.
v Lastly, the consumption of Kalinda (a specific food item) is noted to cause Drishti Kshayakaram, leading to diminished visual strength.
• Various references for the effect of therapeutic procedures on Drishti are also present:
v Acharya Sushruta refers to Putpaka, a Kriyakalpa procedure, as “Drishti Balartha Parama,”[24] emphasizing its effectiveness in enhancing vision. Similarly, Acharya Vagbhata describes Putpaka as having the effect of “Driga Baladhana,”[25] further highlighting its role in strengthening the visual process.
v Acharya Sushruta also mentions “Drishti Prasadana” as a key benefit of the Nasya procedure, which aids in improving visual clarity.
v According to Acharya Vagbhata, the application of Mukhalepa enhances vision strength or capability (Drishti Balam/Drishti Samarthyam). However, engaging in activities like talking or laughing during its application can lead to Drishtiyupghata, potentially harming vision.
v Additionally, both Acharya Caraka and Acharya Vagbhata recognize the value of Taila-Abhyanga (oil massage) and Pad-Abhyanga (foot massage) in promoting Drishti Prasadan, [26] i.e., improving visual clarity.
v Lastly, the use of Prasadan Anjana is explained as effective in addressing visual defects, described as “Drishti Dosha Prasadanartha.”Drishti inherently possesses the characteristic of being naturally adapted to cold, owing to the innate quality of its temperament, known as Sheeta Satmaya. The functional aspect of Drishti operates through Chakshu-Indriya with the assistance of its five components, collectively known as Indriya Panch-panchak. Drishti is formed from the essence of the Panchmahabhuta (Akash, Vayu, Agni, Jala, and Prithvi), known as Panchmahabhuta Prasadajam. When a Roopa (object or Indriyartha) interacts with the Adhisthan (Netra or eyes) via Teja/Jyoti/Agni Mahabhuta (Indriyadravya), it is perceived by Chakshu-Indriya.
This perception is further analyzed and interpreted by Chakshubuddhi, resulting in vision-related knowledge, which is then conveyed to the Atma (spirit). The entire process is orchestrated and coordinated by Mana (the mind). This intricate mechanism can be likened to the process of visual transduction or the vision process.Drishti as both a Structural and Functional Entity
Acharya Sushruta describes Ropana Anjana as “Drishti Bala Vardhnam,”[27] signifying its role in enhancing visual strength, and “Drishti Varnya Vardhnam,” implying the purification or enhancement of the visual color, which reflects its functional aspect.
• In the condition of Pittavidagdha-Drishti, the Drishti turns yellowish (Peetvarna), indicating a structural alteration rather than a functional one. However, if the doshas extend into the Tritiya Patala, it results in impaired day vision, highlighting its functional dimension.
• Similarly, in Sleshmavidagdha-Drishti, the Drishti becomes white (Shweta Varna), and night vision deteriorates, demonstrating both structural and functional impacts. Regarding Nakulandhya, the Drishti of the patient is described as shining like a mongoose’s pupillary area at night, accompanied by night blindness.
• Lastly, in Animittaja Lingnasha, the Drishti becomes clean, clear, and naturally colored (Vaiduryavarna Vimala), while simultaneously experiencing a loss of vision (Drishti Hanayate) [28]. This condition signifies the involvement of both structural and functional components of Drishti.
• In the case of Abhighataja Lingnasha, external trauma leads to Drishti Vidiryate,[29] indicating structural damage to the vision. Subsequently, Drishti Hiyate, or the loss of vision, is observed, which represents the functional impairment.The Pathological Aspect of Drishti
The pathological aspect of Drishti involves its defining symptoms, termed Lakshana, which are indicative of disorders. Drishti, or Chakshu Indriya Shakti, serves as the Lakshana of Chakshu Indriya, and its loss is referred to as Lingnasha. This implies that any disorder causing the loss of visual power (Chakshu Indriya Shakti Nasha) can be classified as Lingnasha. Drishtigata Rogas, therefore, encompass diseases affecting vision [30].
• Lingnasha is a broad term that extends beyond cataracts to include various disorders impairing vision. Conditions affecting the retina, optic nerve, vitreous, visual pathway, uveal tract, hypervitaminosis, avitaminosis, and lens all fall under the umbrella of Drishtigata Rogas. This highlights “Drishti” as encompassing multiple structural components, including the retina, optic nerve, vitreous, visual pathway, uveal tract, and lens.DISCUSSION
In Ayurveda, the term “Drishti” encompasses a broad scope, serving varied purposes in different contexts. The study concludes that Drishti is not a singular entity but comprises multiple structures that align with modern ophthalmological concepts. It represents the components along the visual axis, including the central part of the cornea, pupil, lens, vitreous, retina, and visual pathway, alongside their functional output, which collectively results in vision. Effective treatment of Drishti-related diseases demands a deep understanding of terminologies and their practical applications, aligning with Ayurveda’s core goals—to sustain the health of the health and restore wellness in the unhealthy.
The literary study incorporates extensive data from Ayurvedic scriptures, accompanying commentaries, modern medical textbooks, and relevant articles to provide insight into Netra Sharir (the anatomy of the eye) and its comparison with contemporary science. Acharyas have described the anatomy of the eye, highlighting its shape and size and the structure of various components. Acharya Sushruta details seventy-six distinct eye diseases and their treatments in the Uttara Tantra. The Netra (eye) fulfills dual physiological functions—Roopagrahana (perception of form) and Buddhigrahana (interpretation and cognition)—as it houses Alochaka Pitta. Being predominantly composed of Tejo Mahabhuta (the essence of light/fire), the eye remains vulnerable to the influence of Kapha.
CONCLUSION
It is said that Abhishyandha serves as the root cause of all eye diseases, making it essential for a skilled physician to prioritize its treatment (Prayena Sarve Nayanaamyastu Bhavantyaabhishandnimittamula). The process of visual perception is not solely dependent on the eye itself but is facilitated by the mind. When the mind is disturbed, the eye may physically see objects, but the perception of those images is disrupted.
Understanding the term “Drishti” requires contextual interpretation. In anatomical terms, Drishti can refer to the pupil. In the context of disorders such as Kanch, Timir, or Lingnasha (Drishtigata Rogas), it is associated with the intraocular lens. Similarly, in conditions like Pittavidagdha Drishti and Shleshmavidagdha Drishti, Drishtigata Rogas should be understood as involving the optic nerve or the retina collectively.
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[21] Sushrutasamhita, Uttartantra, Dristhiroga Vigyaniyaadhyaya, 7/16-18. Available from: https://niimh.nic.in/ebooks/esushruta (Accessed on 9 April 2025)
[22] Ashtanghridayam Uttarasthana, Dristhiroga Vigyaniyaadhyaya, 2/30-31. Available from: https://vedotpatti.in/samhita/Vag/ehrudayam (Accessed on 9 April 2025)
[23] Sushrutasamhita, Sutrasthana, Annapanvidiadhyaya, 46/128-29. Available from: https://niimh.nic.in/ebooks/esushruta (Accessed on 9 April 2025)
[24] Sushrutasamhita, Uttartantra, Kriyakalpaadhyaya, 18/21-22. Available from: https://niimh.nic.in/ebooks/esushruta (Accessed on 9 April 2025)
[25] Ashtanghridayam Sutrasthana, Tarpanputpakvidhiadhyaya, 24/12. Available from: https://vedotpatti.in/samhita/Vag/ehrudayam (Accessed on 9 April 2025)
[26] Carakasamhita, Sutrasthana, Matrasheetiadhyaya, 5/10-11. Available from: http://niimh.nic.in/ebooks/ecaraka (Accessed on 9 April 2025).
[27] Sushrutasamhita, Uttartantra, Kriyakalpaadhyaya, 18/55. Available from: https://niimh.nic.in/ebooks/esushruta (Accessed on 9 April 2025)
[28] Sushrutasamhita, Uttartantra, Dristhiroga Vigyaniyaadhyaya, 7/44. Available from: https://niimh.nic.in/ebooks/esushruta (Accessed on 9 April 2025).
[29] Sushrutasamhita, Uttartantra, Dristhiroga Vigyaniyaadhyaya, 7/45. Available from: https://niimh.nic.in/ebooks/esushruta (Accessed on 9 April 2025).
[30] Prof. Verma Anil, Shalakya-Tantra, Part I, Ophthalmology, published by Varanasi, Chaukhamba Orientalia, Reprint 2018, p.277.