Loss of vision (Timira) results from the fact of the deranged bodily Doshas being confined within the fourth Patala (choroid) of the organ. When the vision is completely obstructed by the aforesaid cause, it is called a case of Linga-náśa (blindness). Only a faint perception of the images of the sun, the moon and the stars, the heaven, a flash of lightning or any other such highly brilliant objects is possible in a case of superficial (not deep-seated) Linga-nás'a. The Linga-náśa (blindness) is also called Ni'liká and Kácha. 6.
All external objects are viewed as cloudy, moving, crooked and red-coloured in the Vátaja type (of Timira), while in the Pittaja type they appear to be invested with the different colours of the spectrum or of the rain-bow, of the glowworm, of the flash of lightning, or of the feathers of the pea-cock, or with a dark blue tint bordering on black ; while in a case of Kaphaja Timira, a thick white coat like that of a pack of white clouds or a deep white chowri (Chámara) seems to intervene in everything which look white and oily and dull and appear hazy and cloudy in a fine day, or as if laid under a sheet of water. In a case of the Raktaja type of Timira, all objects appear red or envoloped in gloom, and they assume a greyish, blackish or variegated colour. In a case of Sánnipátika Timira, the outer world looks varcigated and confused, appears as doubled or trebled to the vision (of the patient), and stars and planets, either defective or supplied with additional limbs, seem to float about in the vision. 7- 11.
Parimláyi: - The quarters of the heaven look yellow and appear to the sight as if resplendent with the light of the rising sun, and trees seem as if sparkling with the tangles of fire-flics in a case of Parimláyi, which should be ascribed to the action of the deranged Pitta in concert with the vitiated blood. 12.
Now we shall describe the colours of the pupil in the six different types of Linga-nás'a. The pupil assumes a reddish (Aruna) colour in the Vátaja type of the disease; looks blue or bluish yellow in the Pittaja, white in the Kaphaja and blood-red in the blood-origined one, while it assumes a variegated hue in the Sánnipátika type of Linga-nás'a. A circular patch (Mandala) tinged with a shade of bluish or bluish yellow colour and looking like fire or a piece of thick grass, is formed on the pupil owing to the diseased and aggravated condition of the blood (with pitta) in a case of Parimláyi. In this case the patient is sometimes permitted to catch faint glimpses of the external objects owing to the spontaneous and occasional filtering away of the deranged Doshas obstructing the vision. 13 - 15
The circular patch (over the pupil) in a case of Vátaja Linga-nas'a is red-coloured, and is moving and rough to the touch, while that in a case of Pittaja Linga-nás'a is bluish or yellow or coloured like bell-metal. The circular patch in a case of Kaphaja Linga-nás'a is thick, oily and as white as a conch-shell, a Kunda flower or the moon- resembling a white drop of water on the moving lotus leaf and moving away to and fro when the eye is rubbed. The circular patch over the pupil in a case of Raktaja (blood-origined) Linga-nás'a is red-coloured like a coral or a (red) lotus-petal. A Sánuipátika type of the disease is marked by a variegated colour of the Drishti (pupil) and by the specific symptoms of the different Doshas. 16.
The total number of diseases peculiar to the Drishti is twelve. The six types of Linga-nás'a (Drishti) have been described above. The six other forms of the disease, peculiar to the Drishti (pupil) are named as Pitta-vidagdha-Drishti, Śleshma--vidagdha-Drishti, Dhûma-darśin, Hrasva-Jâtya, Nakulândhyatá and Gam-bhirika. 17.
The disease in which the region of the Drishti (pupil) assumes a yellowish colour, and all external objects appear yellow to the sight owing to the presence of the vitaited (and augmented) Pitta in the region of the Drishti is called Pitta-Vidagdha-Drishti. It is due to an accumulation of the deranged Dosha (Pitta) in the third Patala (coat) of the eye, and the patient cannot see anything in the day, but can see only in the night. 18.
The external objects appear white to the sight when it is affected by the accumulation of the deranged Kapha. The deranged Dosha (Kapha), in this case, is simultaneously divided over all the three Patalas (coats) of the eye. In consequence of this the patient is attacked with nocturnal blindness, being able to see only in the daytime owing to the (melting and) decrease of the deranged Kapha through the heat of the sun. This is known as Sleshma-vidagdha-Drishti. 19.
The external objects appear dusky or smoke-coloured when the sight is affected through grief, (high and protracted) fever, over-straining or excessive physical exercise, or injury to the head, etc. The affection of vision thus engendered is called Dhuma-Drishti (smoky sight). 20.
The disease in which small things can be viewed only with the greatest difficulty (even) in the daytime, but can be viewed (easily and clearly) in the night owing to the :subsidence of the deranged pitta through the coldness of the atmosphere (and a general cooling of the Earth's surface) * is called Hrasva-játy † 21.
The form of occular affection in which the colour of Drishti (pupil) of a man affected by the Doshas resembles (and is found to emit (luminous) flashes like) that of a mungoose in consequence of which the external objects appear multi-coloured in the day time, ‡ is called Nakulándhya. The form of occular affection due to the action of the deranged Vayu, and in which the Drishti (pupil) is contracted and deformed and sinks into the socket, attended with an extreme pain in the affected parts, is called Gambhiriká. 22-23.
Besides the above, there are two more forms of Linga-uás'a of traumatic origin, viz., Sa-nimitta (of ascertainable origin) and A-nimitta (without any manifest or ascertainable cause). Under the first group may be arranged those which are produced by such causes as an over-heated § condition of the head (brain, etc.), and marked by the specific symptoms of (blood-origincd) Abhishyanda, while the second comprises those in which the loss of one's vision is due to causes, such as the witnessing of divine halo or effulgence emanating from the ethereal person of a god, or a Gandharva (demigod), a holy saint, a celestial serpent, or such other highly bright object. In this case the eye is not outwardly affected and the pupil (Drishti) looks as bright and clear as a Vaidûrya gem, while in the former case (of ascertainable origin) the eye is characterised by a sunken or pierced or impaired aspect of the pupil. 24.
* The latter part of the text here seems to be incongruous. Mádhava does not read the last line in his Nidána, nor does Dallana include it in his commentary. Dallana, on the other hand, says that some read this line, but holds, on the authorityof Videha, that the reading is incongruous, in as much as "Hrasva-játya" is said to cause one of the four types of night-blindness.
† Some read Hrasva-jádya in place of Hrasva-játya.
‡ This shows that a man affected with this form of disease cannot see anything in the night.
§ The head is liable to be over-heated by the smelling of poison or poisonous objects or any other strong-scented flower, etc.
We have thus finished describing separately the diagnostic traits of the seventy-six forms of disease which affect the organ of vision. We shall hereafter separately deal with the nature of the medical treatment to be pursued in each case. 25.
Thus ends the seventh chapter of the Uttara-Tantra in the Sus'ruta Samhitá which treats of the pathology of the diseases peculiar to the pupil of the eye.