The Royal Greenwich Observatory informed the Press Association that roughly 15,000 pairs of glasses were bought in the past month, marking a total sellout. The park is an international dark sky reserve and a spokesperson for the park said that they “couldn’t keep up with demand” for eclipse glasses. The Met Office said weather conditions in most of the country will be “more or less perfect” for eclipse viewing. Experts have warned that only special solar eclipse glasses that are ISO 12312-2 certified for the safest eye protection should be used to view the eclipse. Following the 1999 total solar eclipse, the Royal College of Ophthalmologists reported around 70 cases of people experiencing vision problems after watching the eclipse.