I don't have a definitive answer for your question, but Optics and Photonics News did a very well researched article on the optical glass industry prior to and during WW1.

In regards to WW2, the government was seeking civilians to donate large amounts of scrap material to recycle for the war effort. Much of the scrap collected wasn't used. Rubber couldn't be recycled and didn't need to be with the advent of synthetic rubber. Recycled aluminum of the time was inadequate for use in airplanes. Iron was recycled, as was kitchen fat in the production of glycerine. The scrap drives were probably more useful in making the civilian population feel like part of the war effort. Binoculars were also something that citizens could donate, unlike tanks and planes.

Back to optical glass, one of the ingredients use in it's manufacture was potash, which is also used in fertilizer and explosives. Germany was the largest producer of potash before the war, and 75% of the world's potash production was located in Germany or France. The US had approximately 7-8% of potash production prior to the war, but the US demand for agriculture was massive and they typically were large importers of French and German potash. The invention of techniques to get potassium from chemical process as the war progressed alleviated some of the need for agriculture, but potash was still a resource controlled by the Combined Resource Production Board.

Finally there was just the demand for optical glass. If the U.S. General Munitions Board required 1 ton of optical glass every day during WW1, the demand during WW2 would be much higher especially with the increased demand by the Navy. Every binocular donated, just meant more optical glass for other purposes, especially at the beginning of the war as B&L ramped up production.

Here is another article on optical instruments in Australia during WW2 which talks about some of the challenges in the industry. Australia also impressed all civilian binoculars during WW2, and also was a supplier of optical glass to the US.

PART I

By World War II, the United States probably did have the capacity to manufacture enough optical glass, but the telling of why I'm using 'probably' makes this a very interesting question.

One of the more fun things you'll run into in this field is something you're completely unaware of but given your expertise that you should know about, and this question definitely falls into that category for me. So I went down my own rabbit hole to see if I could turn up both an answer along with trying to glean how I'd never even heard of this program, and the explanation of both makes for a much more interesting response.

To begin, let's go back to World War I, when the purpose of the original program was explained in a January 1918 ad in the Boston Medical and Surgical Journal - the predecessor of the New England Journal of Medicine. (Italics are original, by the way.)

NAVY'S CALL FOR BINOCULARS, SPY-GLASSES AND TELESCOPES - "THE EYES OF THE NAVY"

Mr. Editor -

The Navy is still in urgent need of binoculars, spyglasses and telescopes. The use of the submarine has so changed naval warfare that more "eyes" are needed on every ship, in order that a constant and efficient lookout may be maintained. Sextants and chronometers are also urgently required.

Heretofore, the United States has been obliged to rely almost entirely upon foreign countries for its supply of such articles. These channels of supply are now closed, and, as no stock is on hand in this country to meet the present emergency, it has become necessary to appeal to the patriotism of private owners to furnish "eyes for the navy."

Several weeks ago, an appeal was made through the daily press, resulting in the receipt of over 3000 glasses of various kinds, the great majority of which has proven satisfactory for naval use. This number, however, is wholly insufficient, and the Navy needs many thousands more....Toward the end of January it is proposed to distribute throughout the country, posters making an appeal to fill this want of the Navy....

Very sincerely yours, Franklin D. Roosevelt Assistant Secretary of the Navy

This ad, repeated in such finer publications as the North American Review (wealthy literary types who were birdwatchers or race horse fans) and the Army and Navy Journal (retired officers who might actually have their own spyglasses), gives a framework to the request that makes some sense if you know the strategic situation at the time.

While there are a couple of genuinely obscure books on the subject, like We're Certainly Not Afraid of Zeiss: Barr and Stroud, which details the British effort to help a local manufacturer get off the ground, there's a publicly available monograph from a researcher at the University of Glasgow, Steven Sambrook, that explains a large part of what was going on. The largest manufacturer of optical glass, Zeiss, was German, and Britain had to rely mostly on encouraging the build up of local production along with some help from the French. On the other hand, the United States appears to actually have still had fairly decent access to raw materials through April 1917 - despite the British blockade, German shipments apparently went through Scandanavia - and happily sold finished products to the Allies, but after the declaration of war the industry had to completely revamp as that was cut off. At that point, the US government moved in, outright seizing the few factories and sending in various military members with technical experience to oversee things. It more or less worked - Bausch and Lomb's production went up 700% between April and November 1917 - but with one major caveat: while the glass created was considered 'fair and satisfactory for wartime purposes' much of the quality of the glass wasn't up to that of what had been commercially available pre-war.

That in turn was what led to the call for binoculars and spyglasses in late 1917, since what was out in the private sector was better than what was being produced. Combined with the rapid expansion of the fleet to convoy merchants, it does appear as if there was a true need.

So that's half the story of 1917. The other half is equally interesting.

FDR's role as Assistant Secretary of the Navy is perhaps the only area of his life and times that is a bit underresearched. Most historians note only that he a. would have gotten fired for insubordination if anyone else but the immensely patient Josephus Daniels was his boss and b. used the networking from that position to launch his political career into the stratosphere. There's only one book I know of that focuses exclusively on what he did during those seven years - Roosevelt's Navy by de Kay - and while it's a fairly good read, it's also limited in scope and doesn't place FDR's actions in context. To give an idea about why the latter matters, in his single chapter on that period of FDR's life, Jean Edward Smith brings up that it was not only the first time that FDR had ever actually worked hard at anything in his life (and that he was by and large pretty competent) but that the exposure he had to junior and midlevel Navy officers - Bill Leahy sat at a desk across from him for months, for instance - allowed him to create his own black book listing officers with potential that he used to great effect as President to bypass the Navy bureaucracy. This allowed him to jumpstart their careers and thus position them for senior leadership during World War II, much as Marshall did with his own famous little black book for Army officers he'd run across earlier in his career that he heavily relied upon after he became chief of staff (Eisenhower being the most famous he pulled from it.)

But de Kay doesn't have a single reference to "Eyes for the Navy", nor do the vast resources of the Naval Institute, nor did a search through most of my FDR and Navy lit. Indeed, about the only thing that pops up is a couple brief references by the Navy itself to the program, including one of the 30857 certificates FDR got to have an autopen sign when the binoculars were returned to their owners post World War I.