Yes, PVC design flooring can be installed on top of existing tiles. However, it is important to ensure that the tiles are clean, level, and in good condition before installation. Additionally, it may be necessary to use a primer or leveling compound to create a smooth surface for the PVC flooring to adhere to. Overall, with proper preparation, PVC design flooring can be successfully installed over tiles. **

Eyeglass cloths are small pieces of fabric designed specifically for cleaning eyeglasses, sunglasses, and other delicate lenses. They are usually made of microfiber material, which is gentle on the lenses and helps to remove dirt, smudges, and fingerprints without scratching or damaging the surface. Eyeglass cloths are portable and convenient for on-the-go use, making them a popular accessory for anyone who wears glasses or sunglasses. **

Eyeglass coatings are not inherently toxic, as they are designed to improve the durability, clarity, and performance of the lenses. However, some coatings may contain chemicals that could be harmful if ingested or inhaled. It is important to follow the manufacturer's instructions for care and maintenance of coated lenses to minimize any potential exposure to harmful substances. If there are concerns about the safety of a specific eyeglass coating, it is best to consult with an eye care professional or the manufacturer for more information. **

Eyeglass strength is typically measured in units called diopters. The strength of eyeglasses can vary depending on the individual's vision needs. It is important to have an eye exam to determine the correct eyeglass strength needed for clear vision. The eyeglass strength required can range from negative numbers for nearsightedness to positive numbers for farsightedness. **

Protruding eyeglass lenses are lenses that stick out from the frame of the glasses. This can happen when the lenses are too large for the frame or if the frame is too small for the lenses. Protruding lenses can affect the fit and comfort of the glasses, as well as the overall appearance. It is important to ensure that the lenses are properly fitted into the frame to avoid any protrusion. **

Eyeglass lenses produce clear vision by refracting light rays to focus them properly on the retina at the back of the eye. They correct various vision problems such as nearsightedness, farsightedness, and astigmatism by bending light in a way that compensates for the eye's specific refractive error. The lenses help to improve visual acuity and clarity, allowing individuals to see objects more sharply and clearly. **

To determine if the eyeglass prescription has expired, you should check the date of the last eye exam. Eyeglass prescriptions typically expire after one or two years, depending on the state or country's regulations. If it has been longer than the expiration period since the last eye exam, then the prescription is likely expired and a new eye exam is needed to obtain a current prescription. It's important to have an up-to-date prescription to ensure that your eyeglasses provide the correct vision correction. **

Without specific information about the issue with the eyeglass lenses, it is difficult to determine if they are defective. Common issues with lenses can include scratches, warping, or poor prescription accuracy. If the lenses are not meeting the expected standard of quality or are causing discomfort or vision problems, it is recommended to have them assessed by an optician or the place of purchase to determine if they are indeed defective. **