Experts well-versed in the anatomy of the eye aver that the Drishti (pupil) of the eye is the quintessence of the five material elements with that of the eternal light predominating therein - this principle of light neither increasing nor decreasing in this case. It is naturally accustomed to cold from the very nature of its temperament and is covered by the outer coating (Patala) of the organ proper. It looks like a hole and is equal in dimension to that of a Masùra seed or pulse *. The pupil of the eye resembles in its action the phosphorescent flash of a glow-worm or that of a minute particle of fire (in not burning the things coming in contact with it). Now we shall describe the pathology of the twelve kinds of disease peculiar to the region of the Drishti (pupil), as well as of the one which is known as Timira (loss of vision) affecting the Patala (coating over the pupil). 2.
All external objects appear dim and hazy to the sight when the deranged Doshas of the locality passing through the veins (Sirá) of the eye, get into and arc incarcerated within the first Patala (innermost coat) of the pupil (Drishti). 3.
False images of gnats, flies, hairs, nets or cob-webs, rings (circular patches), flags, ear-rings appear to the sight, and the external objects seem to be enveloped in mist or haze or as if laid under a sheet of water or as viewed in rain and on cloudy days, and meteors of different colours seem to be falling constantly in all directions in the event of the deranged Doshas being similarly confined in the second Patala (coat) of the Drishti. In such cases the near appearance of an actually remote object and the contrary (Miopia and Biopid) also should be ascribed to some deficiency in the range of vision (error of refraction in the crystalline lens) which incapacitates the patient from looking through the eye and hence from threading a needle. 4.
* According to Nimi, quoted in Mádhava's commentary by Śrtkantha, the dimension of the Drishti is equal to only a half of that of a Masura-pills/:.
Objects situate high above are seen and those placed below remain unobserved when the deranged Dosha are infiltrated into the Third Patala (coat) of the Drishti. The Doshas affecting the Drishti (crystalline lens), if highly enraged, impart their specific colours to the objects of vision. Even large objects seem to be covered with a piece of cloth. The images of objects and persons with ears and eyes, etc., seem to be otherwise i.e., bereft of those organs. The deranged Doshas situated at and obstructing the lower, upper and lateral parts of the Drishti (crystalline lens) respectively shut out the view of near, distant and laterally-situate objects. A dim and confused view of the external world is all that can be had when the deranged Doshas spread over and affect the whole of the Drishti (crystalline lens). A thing appears to the sight as if cutlinto two (bifurcated) when the deranged Doshas affect the middle part of the lens, and as triply divided and severed when the Doshas are scattered in two parts; while a multifarious image of the same object is the result of the manifold distributions of movability of the Doshas over the Drishti. 5.