There are many different standards in use by the community of optical element manufacturers, designers and users. All of those standards define how to specify and how to test the various optical elements. However, different geographic regions and different industries tend to use different standards. For example, German manufacturers are known for their fondness for ISO 10110, while the US military developed MIL-PRF-13830 and used it for many decades, making it the de facto global standard. The issue of scratches is particularly complicated because it is not always possible to translate the scratch grade by one standard to another and sometimes the translation ends up being statistical (sampling defects to ensure that statistically, the percentage rejected elements will be similar in both methods).