Charakacharya explains that the channels carrying the sensory and motor impulse from the shiras are like the rays from the sun1. Since it is described that Nasa is the gateway for Shiras2. Dvaram hi siraso nasa. Dvaram denotes door, which is used to facilitate the entry or an exit. Acharya Charaka gives importance to nasya as he compiles Nasya in Panchkarma and devote separate chapter on Nasya procedure, types, indications. As mentioned in Astaangahridya sutra Nasya is useful in all the diseases above clavical2. Nasya is the noninvasive method that bypass the blood brain barrier and targets drugs to the central nervous system to treat neurodegenerative disorder as eye resides in head, thus Nasya can be one of the prime procedure to treat eye health and eye disorder.
2. Vagabhatta, Ashtang Hrudaya , Vidhotani Bhashayateeka Sampadaka Vaidya Vadunandana Uphdhyay Chaukambha Publication Year 2003, sutra sthan 20/1
3. Sushrut Samhita, Ayurvedtatva Sandipika-hindivyakhya-vaigyanikvimarshopeta by Ambikadatta Shastri, Chaukhambha Sanskrit Sansthan, Varanasi, uttar tantra chapters 16/9, 17/32, 17/33
4. Charaka samhita, savimarsh- vidhyotani tika- Gorkhnath chaturvedi and pandit Kashinath, Chaukambha Bharati Academy, siddhi sthana 9/88
5. Intranasal delivery by passes the blood brain barrier agent to central nervous system and treat neurodegenerative disease Lean R. Hansan and Willia Frey BMC neuroscience 2008 (Suppl 3) S5 https://doi.org/10.1186/1471-2202-9-53-55
6. Neurologic disorder have varied ocular symptoms, ocular surgery News U.S. Edition, july 1, 2006, Daniele Cruz; Erin L. Boyle.
7. Pharmacodynamics of nasya karma, K.Y. Shrikanth, V. Krishna murty, M. Srinivasulu, www.ijrap.net IJRAP ISSN 2229-3566