How to fix loose sunglasses: tightening the hinge, replacing a screw, and when to stop

Loose sunglasses are almost always a hinge screw that has backed out. The arm flops, the frame sits crooked, and the fix is a precision screwdriver and a quarter turn. A lost screw is replaced from an eyewear screw kit that costs a few dollars. A screw that will not stay tight, a stripped thread or a cracked hinge is a job for an optician, who will usually do it in minutes for little or nothing. The two things that make a loose frame worse are pliers on plastic and glue on a hinge; both end the frame.

Fix 1: tighten the hinge screw

The hinge is a screw through two or more interlocking barrels. Opening and closing the arms thousands of times works it loose. When it backs out, the arm swings freely and the frame no longer holds its shape.

1. Get the right screwdriver. Eyewear screws take a very small flat or Phillips head; a precision screwdriver set, or the driver in an eyewear repair kit, fits. A kitchen knife does not and will chew the slot.
2. Turn a quarter turn clockwise. Hold the frame front steady, seat the driver, turn gently. Stop when the arm opens and closes with slight resistance and stays where you put it.
3. Do not force it. A screw that is tight but the arm still flops has a different problem; see fix 3.

Most loose frames are fixed at step 2 and stay fixed for months. If a screw backs out repeatedly, a tiny drop of screw-thread locker, sold for eyewear, holds it; ordinary thread locker is too strong and can bond the hinge.

Fix 2: replace a lost screw

If the arm has come off entirely, the screw is gone. An eyewear screw kit, sold anywhere glasses are, has an assortment of sizes and a driver.

1. Match the diameter. Try screws from the kit until one threads into the barrel without forcing. The common sizes are around 1.2 to 1.6mm.
2. Check the length. The screw should pass through all the barrels and not stick out below. If it does, some kits include a cutter; an optician will trim one in seconds.
3. Tighten as above.

If you are away from a kit, a paperclip pushed through the hinge and bent over holds the arm on until you get to one. It is not a repair.

Fix 3: when the screw will not hold

Sometimes a screw is tight and the arm is still loose, or the screw turns and turns without tightening. Three causes:

• The thread in the barrel is stripped. A slightly larger screw from the kit sometimes bites; if not, an optician can fit a self-tapping repair screw.
• The barrels have spread. Metal hinges can be closed up gently by an optician; plastic ones cannot.
• The hinge is cracked. On a plastic frame, the hinge is moulded into the frame, and a crack at the hinge is usually the end. Some can be pinned by a specialist; most are replaced.

For all three, an optician is the right call. It is a minutes-long job and most shops do it cheaply or free.

What not to do

• Pliers on plastic. Plastic frames crack under pliers, and a cracked hinge is worse than a loose one.
• Glue. Glue in a hinge stops it moving, wicks into the lens groove, and ruins any chance of a proper repair. No exceptions.
• Overtightening. A screw cranked down strips the thread or cracks the barrel. Quarter turns.
• Bending a plastic front. The front is not what holds the frame on your face; the arms and bridge are. Our slipping post covers what actually holds a frame.

Bent arms

If the arms are tight at the hinge but splayed outward, the frame has been sat on or left in heat; our hot car post covers the second cause. Acetate and metal arms can be reshaped by an optician. Injected plastic and nylon arms mostly cannot; our frame materials post explains which is which.

Our T01 is injected plastic with standard screw hinges. Fixes 1 and 2 apply exactly as written, and it should not be heated or bent to reshape.

Frequently asked questions