How to choose and maintain an ophthalmic trial lens set
Trial lens case is one of the most widely used tools in the optometry process, and the reliable optical trial lens has a direct impact on the refraction result and the comfort of wearing eyeglasses.
Currently, there are many types of trial lens cases on the market, but distinguish from the quantity of lenses, the common trial lens set boxes are divided into 266 type, 232 type, 158 type, 104 type, 68 type, 48 type, 22 type, etc. Generally, optometrists will choose different type according to their fitting needs. In additional, there are also differences in the material of the lens rim, which includes metal, plastic or mixed. Regular single vision trial lens set and progressive trial lens set are both available.
The tips of choosing a good trial lens case
1.Clarity and Scratches of the Lenses:
Good: The lenses are completely transparent without any visible scratches, cracks, stains, oil stains. High light transmittance.
Bad: Lenses that are scratched, stained, blurred, or cracked, can distort vision, reduce contrast, and cause deviation in refraction results.
2. Lens Mounting
Good: The lenses are securely mounted in the rims, flat, no loosening, no tilting.
Bad: Loose lenses, skewed lenses, chipping edges, affecting the optical center and prism effect.
3. Lens Identification:
Good: The power markings (spherical, cylindrical, axial) on the lenses are clear, accurate and easy to identify.
Bad: Worn markings, blurred or even incorrect, which can cause the optometrist to use the wrong lenses.
4. Power Accuracy:
Good: The actual power of the lens (spherical, cylindrical) is exactly the same as the indicated power (within the permissible tolerances, usually ± 0.06D to ±0.12D). We could use lensometer to check it.
Bad: The actual power deviates from the identified power (out of tolerance). This is the most serious problem and can lead directly to refraction errors. Must be checked regularly with a lensometer
5. Cylindrical axis Accuracy:
Good: The axis of the astigmatism lens is marked accurately, and the actual axis position is consistent with the marked axis position (tolerance is usually ± 2 degrees).
Bad: Excessive axial deviation leads to inaccurate astigmatism correction and affects visual clarity and comfort. Must be checked regularly with a lensometer.
6. Optical Center & Prism:
Good: Accurate optical center of the lens, no noticeable unintended prisms (unless specially designed prisms).
Bad: Optical center shift or undue prism in the lens itself, which can cause visual distortion, double vision, or discomfort. The focimeter can be detected.
7. Lens Material and Aberrations:
Good: Use resin or glass materials with good optical quality, and aberrations (especially chromatic aberration) are well controlled. Or we could also choose the professional optical lenses.
Bad: Poor material with noticeable aberrations (e.g., severe edge dispersion) that affect image quality, especially appear on the high-power lenses.
Tips of maintaining the trial lens kit
1. Cleaning:
Use a soft mirror cloth to wipe. Standardized cleaning and disinfection are carried out after each use, and lenses and frames are kept hygienic. The lenses are dirty, with fingerprints and oil stains, and the frames are dirty, which is a hidden health issue.
2. Safe Storage:
There are dedicated, clearly marked storage boxes/cabinets, and the lenses are stored neatly according to the power division to avoid stacking friction. The environment is dry and protected from light. Do not pile up or scatter them randomly, causing scratches, confusion, loss, or moisture and mold.
3. Regular Inspection:
All optical trial lenses (including spherical lenses, cylindrical lenses, and prism lenses) are regularly tested with a calibrated lensometer for power, axis, and prism, and the results are recorded. Eliminate substandard lenses in a timely manner.
Hot-selling models:
266 type plastic circle trial lens set box:
232 type metal rim full aperture trial lens set:
22 type metal rim progressive trial lens set:
