Fashion in eyeglasses goes in cycles in the same way as general fashion. For example the small oval eye spectacle frames were in vogue in the late nineteenth and early twentieth century, re-emerging in the 1990s. Originally the frames were this size for a practical reason – many lenses were ground from the mineral quartz and as it was difficult to obtain suitable pieces of quartz large enough, spectacle lenses had to be kept small!
The mineral quartc is relatively weighty – another very good reason for keeping the lens size down. These days eyeglass lenses are generally made from lightweight plastics called allyl diglycol carbonate. The plastic’s name is often abbreviated to CR-39, standing for Columbia Resin, and it is less than half the weight of glass, which supplanted quartz in the early twentieth century. There are lighter spectacle lens option such as polycarbonate which is feather light and able to withstand heavy impact. Digressing slightly, it is the material of choice for vandal-proof light fittings.
Unfortunately, although impact resistant, the material is certainly not scratch resistant which is an important quality to bear in mind when fabricating spectacle lenses. These days polycarbonate lenses, which are a feature of safety eyewear, are surface treated to make them more resistant to scratching.
Most people want to collect vintage frames to wear them. There are a number of possible pitfalls to bear in mind. For example:
What materials deteriorate?
This is a slightly silly question as all frames deteriorate over time. Those the least susceptible to deterioration are metal-rimmed frames. However with frames from around the mid twentieth century and onwards it is common to find the end tips and the nose pads are plastic coated. The reason for the coating is that the base metal of spectacle frames often contains nickel, and if nickel is in prolonged contact with the skin it can set off nickel dermatitis. End tips & nose pads on such frames do deteriorate due to acid in perspiration, but fortunately a good optical outlet can generally fit replacement pads and tips – these may not totally match the originals, but their positioning means they will be hidden behind your ears or behind the lenses.
Other eyeglass frame material fare less well. A number of plastics were used in the twentieth century:
This material, first developed in 1850, was originally used for the production of movie film and for a short while was used in spectacle frame production. However it is essentially the same material as guncotton (!) and it is now illegal to supply this, either in spectacle frames (or in films either). It deteriorates over time, and with heat gives off an acid smell. However if it does ignite it burns very fiercely as it releases oxygen fuelling the flames. Over time the material crumbles and may auto ignite. This material is so dangerous that museums are not allowed to have examples stored or on display. You certainly do not want any nitrate frames!
This material was developed and used for the production of glasses frames in the early 1920s in France. Unlike its nitrate cousin this material was not flammable. It is a stable material and easily worked and colored. It continues until today to be used from spectacle frames. Over time, if stored in overly hot conditions it will tend to lose its plasticity and elasticity, making it brittle and the shapes to warp.
This very strong material gained popularity in the fifties and sixties for upswept cats-eye supra frames. These eliminated the lower frame rim, substituting a nylon cord (like fishing line) which was held under tension in the lower rim of the spectacle lens that had a groove cut to take the nylon cord. Although the nylon supra design was strong, the material is very brittle, needing a great deal of heat before it can be adjusted to fit the person’s face properly. If insufficient heat is used, it is common for the frame itself to snap and it cannot then be repaired. However it is actually relatively straightforward for the nylon cord to be replaced, should that break over time.
There are various other materials such as carbon fibre, which enjoyed brief popularity in the seventies, but there is not enough space in this article to cover less popular materials any more comprehensively.
Are the frames safe to wear?
Well, with the exception of cellulose nitrate (see above) yes, they are all safe.
Can prescription lenses be put into a vintage frame?
Of course any frame needs to fit you correctly. Some prescriptions are not suited to certain frames, and the interpupillary distance (how far apart your eyes are!) will influence how thin the lens can be at the edge. You will need to show your chosen frame to your eyecare practitioner as it is possible to calculate the expected thickness of the lens edge for your prescription and frame chosen.
If your frame has a plastic rim that totally surrounds the lens, this will need to withstand being heated, stretched larger than the lens bevel, then cooled which will shrink the rim to hold the lens firmly. Your eye care specialist / optometrist will be able to advise on potential problems – glazing an old frame in this way will probably only be undertaken at you own risk. It will be impossible for an optician to predict, just by looking at it, how brittle your vintage frame is, and whether the rim will tolerate this degree of manhandling. Reputable companies supplying vintage spectacles from the fifties will be able to give an indication on how robust the frames are likely to be but it is likely that they too will be able to offer any cast-iron guarantees, for the same reason.
There is no doubt that vintage and retro frames really can add a unique edge to your fashion style. You may collect simply for the joy of owning a piece of history, or for use in costume drama, or to wear yourself, but whatever the reason – good luck with your hunting!