But it is most certain that this Disease is also begot by adstriction and compression of the Optick Nerves; which compression may come both or a moist humor gathered about the optick Nerves, and pressing upon them: as also of blood, filth, or matter: Whence somtimes certain tumors rising in those parts, produce the like Disease. For Experience teacheth, That somtimes blindness in one Eye, somtimes in both, comes upon inflamation of the Brain, and from Phrenzy in malignant Fea∣vers. And Platerus reports lib. 1. Observation, That he saw a blindness which came from a round tumor growing in the Brain, and compressing the optick Nerves, which appeared by opening of the Head after the Patient was deceased.
Finally, Wounds in the Head, in which the Optick Nerves are divided, without controversie do cause that the Animal Spirits can no more come to the Eyes.
This Disease is known, in that the Eyes seem to be in their natural condition, and there is no fault apparent in them, only the Pupilla seems blacker and larger. But in distinguishing the differences of Causes, there is great difficulty; for although the Disease coming of blood or matter is known by inflamation, aposthume, or wound going before, yet no certain sign can be given by which we can di∣stinguish a compression made with flegm from an obstruction: but we may in some part conjecture, for in the obstruction only of the optick Nerve, the Eye is only affected; but if a compression be made of the same Nerve by flegm gathered about the roots of the Eyes and Mamillar Passages, that matter possesseth other parts of the Brain, and then all or some of the other Sences are hurt; but if it seize only upon the Optick Nerves, there is more plenty of humor sent forth at the Nostrils, and the Patient perceives a heaviness in the fore part of the Head, especially about the Eye-brows.
As to the Prognostick part; If this Disease be absolute, that is, if there be a total loss of sight, e∣specially if it come from obstruction of the optick Nerves, it is for the most part incurable; as we see in Palseys also, that they are scarce or never cured which come from the obstruction of the Nerves, e∣specially if the Patient be old. But if the obstruction be imperfect, which only causeth a diminution of sight, but not blindness, there is more hope of recovery, although it cannot be brought about with∣out much pains, and long use of Medicines.
But if this Disease come of humors gathered in the fore part of the head, which compress the Nerves, it may be more easily cured. So saith Fabricius Hildanus, observ. 19. cent. 5. That a cer∣tain man after a strong vomit lost his sight, and that he cured him with giving him the same Medicine again; for as the humors being too much stirred by a violent vomit, and cast upon the Optick Nerves, compressing them, did hinder the passage of the Spirits to the Eyes: so the same humors being carried away by the same Medicine, the disease became cured. Almost the like story is mentioned by Sen∣nertus of a certain Student, who taking too strong a Purge became suddenly blind. He also affir∣meth, That certain women after they had conceived with child, became blind through the straightness of the optick Nerves, and that this Disease went away after four or five months, or in the time of their Delivery.
We also have seen some which fell suddenly into extream diminution of sight, who within fifteen daies, were cured by universal Evacuations, and some revulsions, and by the easiness of the Cure we supposed that the humor was not fastened within the substance of the nerve, but only gathered toge∣ther in the Brain about the original of those Nerves.
For the Cure of this Disease, The matter fastened upon the Nerves, or cleaving thereto, and ma∣keth the obstruction or adstriction, is to be evacuated; which cannot be done, except first the whol body be clensed, as Galen saith 4. meth. The Eye is not to be cured before the whol Head, nor the Head before the whol Body.
And that Remedies may be set down in a convenient Method, we will first set down a Course of Diet, which must be attenuating and moderately drying.
And first, The Air must incline to hot and dry, and a thick, cold, cloudy, and moist Air, must be altogether avoided. Let him cat meats of good and laudable Juyce, avoiding them which beget gross Juyce, as Pork, and all Swines flesh, Geese, Fish, Pulse, Cheese, and the like; as those which are windy, and fill the head, as Milk-meats, and hot Spices, viz. Pepper and Ginger, &c. Let his Bread be made with Fennel Water, or with the Seeds thereof; being careful that the Wheat of which it is made, be not mixt with Darnel, which all the Ancients beleeved to be very naught for the Sight: hence in the Comedy, he that derideth another for defect in his sight; I think (saith he) thou hast sed upon Darnel. In the sawce to his Meat, and in his Broths, let him use things extenuating, as Hysop, Fennel, Marjoram, Bettony, Sage, Eye-bright, and especially Nutmeg, which strengtheneth the Brain, and clears the Sight. He must eat Turneps often, which are thought to quicken the Sight: So do Sparrows, Pidgeons, often eaten. Cold Herbs must be forborn, and especially Let∣tice, which hurts the Eyes.
Let him take but a smal quantity of Meat at a time, and let the sick man never fill himself immo∣derately: Let his Supper be less than his Dinner: and to abstain from a Supper twice or thrice in a week is very good. At his Meat, instead of Salt let him use this Pouder following: