Stock optical lenses

When purchasing stock lenses, you must prioritize the Refractive Index (e.g., 1.56, 1.60, 1.67, or 1.74) as it determines lens thickness and weight. Ensure the Abbe Value is appropriate for the index to minimize chromatic aberration. Additionally, verify the Specific Gravity for wearer comfort and the UV400 protection rating to ensure 100% blockage of harmful ultraviolet rays. For stock finished lenses, confirm the diameter (typically 65mm to 75mm) matches your frame glazing requirements.

The longevity of a lens depends on its coating stack. Demand suppliers provide test data for Anti-Reflective (AR) coatings, specifically the luminous reflectance (Rv < 1%). For durability, check the Bayer Ratio for scratch resistance (Hard Coat). If sourcing 'Blue Cut' lenses, distinguish between substrate absorption and coating reflection technologies. High-quality stock lenses should also feature a Super Hydrophobic (Easy-to-Clean) top coat with a high water contact angle (>110°) to prevent smudging.

Optical lenses are medical devices. For the US market, compliance with FDA 21 CFR 801.410 (Impact Resistance/Drop Ball Test) is mandatory. For the European market, lenses must carry the CE Mark and comply with ISO 14889 (Fundamental requirements for uncut finished lenses) and ISO 8980 (Optical tolerances). Ensure the supplier provides a Declaration of Conformity (DoC) and is registered under ISO 13485 for medical device quality management.

Request a Batch Inspection Report that details the diopter tolerance (typically ±0.06D for low powers) and cylindrical axis precision. Use a Lensmeter to verify a random sample from the shipment against the packing list. For stock lenses, surface quality (S/D 60/40 or better) is critical; ensure there are no bubbles, inclusions, or 'orange peel' waves that could impair vision.

The primary risk is optical power deviation or 'mixed power' within a box, which can lead to high return rates from your retail clients. Another risk is coating delamination caused by poor chemical bonding during the vacuum deposition process. To mitigate this, use Made-in-China.com's Secured Trading services to ensure the goods meet your technical specifications before final payment is released.

Stock lenses are high-volume commodities. Negotiate based on a 'Mixed Power' MOQ rather than a per-SKU MOQ to maintain inventory balance. Aim for tiered pricing where the unit cost drops significantly once you exceed 1,000 pairs per index. Ask for free samples (5-10 pairs) to conduct independent lab testing for impact resistance and coating durability before committing to a container-level order.

Lenses are sensitive to pressure and temperature. Ensure the supplier uses double-walled corrugated export cartons and that individual lens envelopes are packed tightly to prevent friction scratches. For sea freight, request desiccant silica gel packs inside the master cartons to prevent moisture from affecting the lens envelopes or causing 'clouding' on the lens surface. Always clarify Incoterms (FOB or CIF) to understand where the risk of loss transfers.

Check if the supplier is a 'Gold Member' or 'Audited Supplier' on Made-in-China.com, which indicates they have undergone third-party verification by firms like SGS or Intertek. Review their Business License to ensure their scope includes 'Optical Lens Manufacturing' and not just 'Trading.' Request photos of their AR Coating Cleanroom and Automatic Edging/Polishing lines to confirm their production capacity.