In the precision-driven world of optical manufacturing, the quality of lens coatings has become one of the most critical differentiators between premium eyewear and average products. Anti-reflective (AR) coatings, hard coatings, mirror coatings, and other functional layers are essential for enhancing light transmission, reducing glare, improving durability, and protecting against scratches and environmental damage. However, even minor defects such as scratches, pinholes, uneven thickness, or improper adhesion can severely compromise functionality, leading to reduced clarity, increased scattering, or even complete coating failure. For B2B buyers sourcing eyewear, understanding the rigorous quality control ecosystem—from coated lens inspection and sunglass lens QC to optical lens appearance inspection, 100% visual inspection after lens coating, and post-coating lens surface inspection—is essential for ensuring product excellence and protecting brand reputation. The inspection of optical resin eyeglass lenses is a sophisticated, multi-stage quality assurance process integral to delivering safe, effective, and cosmetically pleasing vision correction. This comprehensive guide explores the critical importance of lens coating inspection, the methodologies and standards that govern sunglass lens QC, the meticulous procedures of optical lens appearance inspection, and the non-negotiable practice of 100% visual inspection after lens coating as part of a complete post-coating lens surface inspection regimen.