Regarding Colored Spectacles

Since the myth of mid-century sunglasses as signs of syphilis is still running around, I decided to compile some resources here for future reference.  It is built off of this thread from The Sewing Academy, with the addition of links where missing, and some further resources.  

First, let's see what period sources say about colored spectacles: who is wearing them, when, and why.  For this purpose, I am including all tinted lenses, including blue, green, and gray/smokey/neutral, etc.

Colored spectacles as a protection for weak eyes (or not)

Neutral-tint glasses are préferable to any others for the defending delicate eyes against an excess of light of any kind...
--The Retrospective of Practical Medicine and Surgery (1851), page 217 

Coloured Glasses are either of green, blue, or grey, the latter are sufficient for trivial cases and, as any kind of work can be seen through them, they do not interfere with the ordinary occupations. For cases of inflammation which are aggravated by light, and where there is a weakened or irritated condition of the nerve, the dark blue or green should be used; those which are made with a hinge with a double lens are best, as they prevent the light from entering at the side.  ---The Family Doctor (1858) 

Some persons living in cities who have weak eyes find permanent relief only by a change of residence to the country.  Persons of this description will find an advantage in wearing some  defense before their eyes, especially when exposed to heat, sunshine, or  glaring lights. This will be best if of a green color. Spectacles that do not magnify, of the same hue, are well suited for this purpose.  --The Family, Farm and Gardens, and The Domestic Animals (1859)

 Within the last twelve months we have succeeded in procuring glass of rather an inky blue or crape colour. This is called neutral tint and has been found particularly desirable for spectacles operating as shades for weak eyes.
--A Familiar Treatise on the Human Eye (1852), page 37

Spectacles of green glass ought to be used never. When we were young ,we were green enough to use green glasses for many years...One morning the old gentleman said, "It seems to me all our young men are growing blind." "Why so sir?", we inquired. "Because so many of them wear glasses," said he. We replied, "We had been advised to wear them on account of weak eyes." "For that very reason", said he, "I advise you to leave them off."
--The Medical World (1857), page 672

In this case, the narrator has overworked his eyes from painting rather than reading, and attempts to sooth the irritation with green spectacles:

This constant employment of my eye day and night together with the indulgence of my curiosity together with the use of a microscope produced an extreme irritation and sensitiveness, so that when any one remarked that an artist required good eyes, the mere mention of the word set my eyes to watering. I could not paint with green spectacles, and found them prejudicial to use at all; because, although objects seen through them were agreeable enough, yet on looking out of them, everything necessarily had a redness which was offensive. My bandana handkerchief showed me that a subdued purple was the best medium, as its complimentary influence was a subdued orange hue. The pale, purplish, blue glasses, now used, are not of the proper color, entirely to relieve the sight.
--The Crayon (1856), page 164

Colored spectacles for protection from the environment

The Illustrated Catalogue of Mathematical, Optical and Philosphical Instruments (1859) features "wire gauze eye protectors" with green or blue glasses, "an excellent article for railway travelling":

Catalog listing for blue and green glass eye protectors.

...also in hot climates, the blue parallel glasses will be found advantageous, as they modify the intensity of the light. I would recommend blue glasses also for walking, or reading by candle-light.
--A Familiar Treatise on the Human Eye (1852), page 37

During the last century green glasses have been employed to protect the eye from excessive light, and they are decidedly the best of all coloured glasses...Fashion, however, always the victim of ignorance, has introduced blue glasses which as they absorb different parts of the spectrum unequally and transmit the extreme violet and blue rays are more mischievous than useful. Science, however, the unwearied benefactor of an ungrateful community, has substituted for green and blue media an opaque glass of no colour, by means of which we can moderate in any degree we choose, the light which reaches the eye.
--The North British Review (1857), page 182

Another source takes the opposite few--that green and grey/smokey lenses are harmful and blue less so:

Green spectacles are without exception extremely injurious, and physicians are much to blame when they recommend their use...To protect the eyes against the glare of the light when walking over snow covered regions in bright sunshine, or when working near the fire spectacles made of light wire with large round openings in which instead of glass black crape is fixed tightly are most useful. The only color of glass allowable is a light blue colored by cobaltum the color ought to be of such a shade that bright sunlight when falling through the glass appears snow white without blinding the eyes. Glasses of the color commonly known by the name of "London smoke" are injurious they ought not to be used.
--The Homeopathic Domestic Physician (1859)

We also have a few references to colored or smokey glasses used for viewing an eclipse (this is not the modern best practice).

Colored spectacles being book-ish or otherwise unappealing:

"There were 'black spirits and white,' of every shade; strong-minded women, with diminutive hoops, eye-glasses, green spectacles, and unfashionable bonnets; weak-minded men, with a superabundance of hair and an evident predilection for the Grahamite diet, and the usual scattering of old ladies, blue stockings, silly girls, and noisy little boys."--Ought American Slavery Be Defended? (1858)

In one corner stood three young ladies, talking to each other with much excitement and volubility. They were decidedly blue. They were dressed in the fashion of strong-minded women, without any vanities of crinoline, stays, or embroidery, and wore plain coarse dresses made in a masculine style, and very much ornamented with pockets...Then there was a literary lady in blue glasses and dingy dress, who had lately published a novel, and whom every one thought fit to compliment upon such an achievement.
--Now or Never: A Novel (1859)

"Volumes in old worm-eaten bindings, and written in strange languages long since dead and forgotten upon this earth, but they all seem familiar to this pale student whose blue spectacles bend eagerly over pages of crabbed Arabic, with as much interest as a boarding school Miss devours the last new novel."
--Three Times Dead; or The Secret of the Heath (1854)

In Elizabeth Gaskell's 1865 novel Wives and Daughters, Dr. Gibson intercepts a love note send to his 17-year-old daughter by one of his apprentices. The ensuing conversation contains these lines:

"Would it tend to cure your—well! passion, we'll say—if she wore blue spectacles at meal-times? I observe you dwell much on the beauty of her eyes." "You are ridiculing my feelings, Mr. Gibson. Do you forget that you yourself were young once?"

Sarcastic as he can be, the most straightforward reading (to me) is that the hypothetical blue glasses will make Molly look less pretty, not that her own father wants people to imagine she has a venereal disease. For, as he continues: 

" But remember how soon a young girl's name may be breathed upon, and sullied. Molly has no mother, and for that very reason she ought to move among you all, as unharmed as Una herself."

Miscellaneous

Harper's (1855) "An Evening At Newport": a character's blue spectacles are regularly remarked upon as a sort of affectation.

Researches in Colour-Blindness appeals to the common use of blue spectacles for a thought experiment to explain color-blindness, and in another instance refers to red-and-green spectacles being used to treat the same.

Diseases
And now for the gross bit: why do period sources say about treating syphilis and other venereal diseases?  Notice regarding the following links: the subject is rather gross and the illustrations moreso, even if they are presented with period delicacy. 

A Treatise on Gonorrhea and Syphilis (3rd edition, 1865), written by a doctor for other doctors' reference, discusses treatments and gives case studies.  In over 450 pages, there is no mention of any sort of glasses, spectacles, or lenses (of any hue) being used to treat any of the diseases under discussion. The Lancet (1854) also has case studies about the spread of the syphilis from parents to children, but no mention of glasses, spectacles, or other eye-remedies being prescribed. A Dictionary of Practical Surgery (1854) does mention syphilis among other conditions which can affect the eyes, but again makes no recommendation for or connection with glasses or spectacles (so far as I've read).