You bought a pair of acrylic frames, maybe from GlassesNG, House of Lunettes, or off a shelf at a market in Lagos, and three weeks later they are sitting crooked on your face, sliding off your nose every time you look down, or digging into one ear. You go back to the shop and they are closed. You search online and every article tells you the same five things in the same flat voice. None of it feels like someone who has actually held a pair of frames in their hands.
This guide is different. It is written from what opticians actually do, what acrylic frame specialists say, and what goes wrong when people rush it.
First: Acrylic Is Not the Same as Acetate
Most people use “plastic frames” as a catch-all. But acrylic and acetate behave differently under heat, and confusing the two is where most home adjustment mistakes start.
Acetate is made from plant-based cellulose. It is denser, slightly more forgiving, and more common in premium optical frames. Acrylic, technically polymethyl methacrylate, or PMMA, is harder, lighter, and more brittle at room temperature. It needs heat to become pliable, but it also reaches its damage threshold faster than acetate does. If you have ever seen a pair of glasses crack along the bend point with a white stress line, that was almost certainly acrylic being forced while still cold.
Kirk and Kirk, one of the few eyewear brands that works exclusively with acrylic for part of their range and publishes specific adjustment guidance for opticians, states that acrylic frames must be heated until the material moves with virtually no resistance before any bend is attempted.
Their instruction is not “warm”, it is properly soft.
That distinction matters enormously when you are working with your hands at home and do not have a professional frame heater.
Quick answer — how to adjust acrylic frame glasses
- Heat the section you want to adjust using a hair dryer on low heat for 25 to 40 seconds, moving it continuously to distribute heat evenly.
- The acrylic should feel slightly soft and offer very little resistance when you press it gently.
- Make one small adjustment with your hands.
- Hold the new position for 15 to 20 seconds.
- Immediately cool the area under cold running water to lock the shape.
Never attempt to bend acrylic cold, it will crack.
Why Your Frames Shifted in the First Place
Before adjusting anything, it helps to understand what caused the problem. Acrylic frames lose their shape through a small set of repeatable causes, and identifying yours determines what exactly you need to fix.
The most common cause is one-handed removal. Every time you pull your glasses off with one hand, which most people do without thinking, you apply uneven lateral force to one temple arm. Over weeks, the frame develops a slight twist. One lens ends up sitting closer to your face than the other. The glasses look crooked in the mirror even though nothing dramatic happened to them.
The second cause is heat exposure. Leaving acrylic frames on a car dashboard, near a gas cooker, or in direct afternoon sun for extended periods softens the material unevenly. The frame reshapes itself under its own weight or the surface it is resting on. By the time you notice, the deformation is already set.
The third cause is often misdiagnosed: a loose hinge screw. A loose screw allows the temple arm to droop slightly, which changes the angle at which the frame sits. This looks like a frame alignment problem when it is actually a thirty-second fix with a precision screwdriver.
Check the screws first before heating anything.
What You Actually Need
You do not need an optical shop for most of these adjustments, but you do need the right approach. The tools are almost certainly in your home already.
- A hair dryer, low to medium setting only. Never high.
- A bowl of warm water, not boiling, not cold from the tap. Comfortable to hold your hand under.
- A microfiber cloth or clean towel.
- A small flat-head or Phillips screwdriver, or a basic eyeglass kit (available at most pharmacies and phone repair shops for well under two hundred naira).
- A flat mirror you can set on a surface and look into straight-on, not handheld.
Cold running water matters more than most guides acknowledge. Once you have adjusted a warm acrylic frame, cooling the adjusted area quickly under cold water is what locks the new position. Without this step, the material retains some memory of its original shape and gradually reverts.
This is why many people repeat the same adjustment twice in a week and assume the method failed, the method was fine; the cooling step was skipped.
Do not do this
- Do not use boiling water.
- Do not hold a hair dryer on one spot without moving it.
- Do not attempt any bend while the frame still feels stiff.
If the acrylic is resisting you after 30 seconds of heat, apply more heat, not more force. Forcing cold or under-heated acrylic is what causes the white stress fractures and cracks that cannot be repaired.
How to Adjust Acrylic Frames for the Most Common Problems
The frame sits crooked — one side higher than the other
This is almost always a temple arm or hinge issue. Stand in front of your flat mirror with the glasses on. Note which side sits lower. The temple arm on the higher side is the one to correct.
- Check the hinge screws before anything else
Place the glasses on a flat table, lenses facing down. If one temple arm lifts off the surface, the hinge screw on that side may simply be loose. Tighten it gently clockwise with a precision screwdriver. This alone resolves the problem more often than people expect. - Apply heat to the higher-side temple arm
If the screw is tight and the frame is still crooked, heat the higher-side temple arm from just behind the hinge to about halfway down. Move the hair dryer back and forth for 25 to 35 seconds. Test the plastic with a gentle fingertip press, it should give slightly. If it feels rigid, continue heating. - Bend the arm gently downward
Hold the front of the frame steady with one hand. Apply very light downward pressure to the warm temple arm with the other. The adjustment needed is almost always smaller than you expect. A two to three millimetre correction is often enough. Hold the position for fifteen seconds. - Lock it with cold water immediately
Run cold water over the adjusted section for ten to fifteen seconds while holding the frame in the corrected position. Dry with a cloth, put the glasses on, and reassess. If more correction is needed, repeat the full cycle, always starting with heat.
The frames slide down your nose
Glasses slide down most often because the temple tips, the sections that hook behind the ears, have lost their downward curve from being stretched during one-handed removal. The fix is straightforward, but it is in the tips specifically, not the full temple arm.
- Heat only the last four to five centimetres of each temple tip
Apply the hair dryer to the tip section for 20 to 30 seconds until that area is soft. You should not need to heat the full arm for this adjustment. - Increase the downward angle
Hold the arm with both hands, thumbs on top, fingers underneath at the bend point, and gently push the tip further downward. The goal is a tighter wrap behind the ear. Work in small increments, not one large bend. - Cool under cold water, then test by wearing
Do not assess the fit immediately after adjustment. Cool the tips, put the glasses on and walk around for two minutes before deciding if more adjustment is needed. The feel changes once the frames settle on your face.
If adjusting the tips does not solve the sliding, the nose bridge may be too flat. On acrylic frames with a built-in bridge rather than separate nose pads, you can heat the bridge area and apply gentle inward pressure to deepen the nose seat.
Alternatively, self-adhesive silicone nose pads available at pharmacies add grip without any permanent modification and cost almost nothing to try first.
The frames are too tight at the temples or behind the ears
- Heat the full temple arm from hinge to tip
Apply the hair dryer along the entire arm for 30 to 40 seconds, keeping the dryer moving at all times. - Identify where exactly the pressure is
| Problem Area | Adjustment Point | Action |
|---|---|---|
| Temples | Near hinge | Gently pull outward |
| Behind ears | Tip curve | Straighten slightly |
- Make multiple small passes
Undershoot deliberately and repeat. A frame that is still slightly tight after the first pass can be widened further in a second cycle. A frame that has been over-widened is much harder to bring back without risking cracks at the hinge corners.
“The most reliable way to damage an acrylic frame at home is to combine impatience with cold plastic. The heat is not optional, it is the entire method.”
What Professional Opticians Do Differently
The steps above mirror what a professional does, with one meaningful difference in tooling.
Opticians use a frame heater, a device that blows controlled warm air at a consistent temperature from a ceramic element. This heats the frame more evenly than a hair dryer and gives the dispenser a much clearer sense of when the material is ready to bend.
Professionals in some practices, particularly older-style shops, use hot sand pans for the same reason: even, controlled heat without moisture.
At practices like The Eye Doctor’s in Lagos, which has branches at Victoria Island, Yaba, Gbagada, Ajah and Ikeja, adjustments are handled as a standard part of the dispensing process. GlassesNG and House of Lunettes both stock and service optical frames.
Most established optical practices in Nigeria will adjust frames they sold at no charge, particularly within a reasonable period after purchase. If you bought your frames from an optician in the first place, going back is almost always the fastest and safest option.
The DIY method in this guide is for situations where returning to the store is not practical, or where the issue is minor enough that handling it yourself genuinely makes sense.
The Mistakes That Actually Damage Acrylic Frames
These are errors that cause permanent damage. None of them are obvious until after they happen.
Bending without heat is the most common and most damaging. Acrylic looks flexible because it is thin, but the material is under internal stress at room temperature. Forcing a bend cold creates micro-fractures visible as white stress lines at the bend point. These weaken the frame even when the glasses still appear intact, and the damage does not reverse.
Using boiling water is the second mistake. Temperatures above approximately 80°C cause acrylic to bubble, warp permanently, or discolour. Hot tap water, warm enough to be uncomfortable to hold your hand under, but not boiling, is the practical upper limit for home adjustment.
Heating the lenses along with the frame is a separate category of damage. Most lenses, prescription or fashion, carry anti-reflective or UV coatings that degrade under direct heat.
- When soaking temple arms in warm water, the lenses should not enter the water.
- When using a hair dryer, direct the airflow at the frame material and away from the lens surface.
Repeating heat cycles without fully cooling between them progressively weakens the material’s ability to hold shape. Each cycle should be followed by a complete cold-water cool and a proper assessment before the next round.
Frequently Asked Questions
How do I adjust acrylic frame glasses at home step by step?
Heat the section you want to adjust with a hair dryer on low for 25 to 40 seconds, keeping the dryer moving. Press the plastic gently, it should feel soft and give slightly. Make one small adjustment with your hands. Hold the new position for 15 seconds, then run cold water over the area immediately for 10 to 15 seconds to lock the shape. Repeat the full cycle if more correction is needed. Never skip the cold water step.
Can acrylic glasses be adjusted without heat?
No. Acrylic is a hard thermoplastic that does not bend safely at room temperature. Attempting to adjust without heat almost always causes stress fractures or cracking.
The heat is not a shortcut, it is the method.
Why do my glasses keep reverting to their old shape after I adjust them?
The most likely cause is skipping the cold-water cooling step. When you adjust a warm frame and allow it to cool slowly in open air, the material partially retains its previous shape. Cooling it quickly under cold water while holding the corrected position is what permanently sets the new shape.
How do I tell if my frames are acrylic or acetate?
| Material | Feel | Visual Clues |
|---|---|---|
| Acetate | Heavier, slightly waxy | Often layered patterns |
| Acrylic | Lighter, harder | Clearer or more uniform colour |
Any optical store in Nigeria can confirm the material. When in doubt, treat the frame as acrylic and use conservative heat, the approach is safe for both.
Where can I get acrylic glasses adjusted professionally in Nigeria?
The Eye Doctor’s has locations in Victoria Island, Yaba, Gbagada, Ajah and Ikeja. House of Lunettes and GlassesNG both carry and service optical frames. Any registered optical practice can adjust frames, most do it free if they sold the glasses, and for a small fee otherwise.