The importance of the organ of vision i.e. eye which is stated as pradhama in the sense organs, has been established by relegating one of the subdivisions of pitta for its function.
Location: – Both Sushruta and Vagbhata have located the Alochaka pitta in the eye and it is responsible for vision. (Sushruta:sutra:21/10)
Charaka has not mention of it as a separate entity, except for including its function among those of pitta in general. Chakrapanidatta, commenting on the above, attributes this function to Alochaka pitta. Sushruta states that the pitta which is located in the eye is known as the alochakagni. Vagbhata, in his Ashtanga Hridaya, has also stated that Alochaka pitta is situated in the eye Bhela samhita gives a little more details that –
Functions of Alochaka Pitta:
According to Sushruta, the function of the alochakapitta is to catch the image of any external object presented to the eye.(Sushruta:sutra:21/7-10). According to Vagbhata, the function of the alochakapitta is the perception of rupa including the colour. (Ash.Hri.sutra12/14) Bhela states two types of alochakapitta- chakshurvaiseshika and Buddhi vaiseshika.
Chakshurvaiseshika alochakapitta- This pitta, being located in the eye, begines to function after the correlation of the atma and manas when the object has made its contact with it leading to the production, in Chitta, of the knowledge of the characteristics like form, colour etc. of such things as flowers, fruits, leaves etc. in all forms of life- possessing the eye.
Buddhivaiseshika alochakapitta- This pitta is located in Sringataka i.e. between the two eye brows. It seizes subtle objects, retains and recalls them. It is a factor which enables concentration, response and cogitation. Bhela also stated that the Alochaka pitta is excited by varsa, seta and atapa.
Buddhivaiseshika alochakapitta is responsible with the processes of memory mainly associated with experience through vision.