3-Piece Rimless Eyewear: How to choose the best styles for patient satisfaction
Drilled rimless eyewear can pose a challenge for ECP’s: not only do they require special tools and dexterity to mount, and this takes time and practice to master. Knowing what qualities to look for in a 3-piece frame line is half the battle and can save both you and your patients the hassle of frequent remountings or cracked lenses.
Frame selection: more than just style
A wide range of rimless eyewear on the market makes it difficult to choose which lines to carry. Rigid frames that have zero flex at the bridge or temples can lead to loosened and cracked lenses over short periods of wear. This is because constantly unfolding and folding the temples and taking them on and off the face places stress on the areas where the chassis is attached to the lenses, transferring the flex to the lenses rather than being absorbed by the frame. Nut and bolt mountings will frequently work their way loose within a few months of regular use, and plastic compression bushings will stretch out and no longer grab the barbs of the frame. This leads to overall patient dissatisfaction with their frame choice and added work and expense for the ECP. Securing these frames with a drop of superglue is often used as a last resort but this can make the frame unusable for future lens changes–glue becomes embedded in the threaded posts or makes a mess on the lenses which is unable to be cleaned off. It also partially melts polycarbonate material which will compromise the integrity of the lenses and reduce their lifespan. Compression mountings pose their own challenges–having the correctly-sized plugs on hand, plus pliers, clippers, and the dexterity to juggle three things in your hands at once.
Lens material is crucial
Drilling into a lens compromises its integrity, and some materials handle this better than others. CR39 is susceptible to breaking and Polycarbonate develops stress cracks around drill holes. The ideal lens material for average prescriptions is 1.53 Trivex, a urethane-based monomer that provides superior optics & solvent resistance when compared to Poly. 1.67 Hi-Index for stronger prescriptions holds up well in rimless drill mountings but still must meet minimum thickness requirements.
Practice makes perfect
Look for frames which are made from high quality, flexible materials that are resistant to solvents and corrosion. Save old lenses instead of throwing them away. Practice unmounting and remounting different rimless styles such as the nut & bolt (which require plastic and metal washers and a hex nut driver) and compression-style frames. I recommend a pair of double nylon-jawed parallel pliers (often found in the jewelry making section of craft stores), compression sleeve removal pliers (eliminates any damage to the frame from pulling it out of the lens), and a pair of cutting pliers specifically designed for trimming plastic bushings. Try overtightening until the lenses crack so you get a better idea of the limits these lenses can withstand. The more familiar you become with how these frames are constructed the easier it will be to adjust and mount the patient’s lenses in the office.