To further protect gorillas from disease transmission, many sites are implementing the best practice guideline of having visitors and all staff wear surgical masks while within 10 meters of gorillas. Wearing the mask further reduces the risk of disease transmission to the gorillas.
Tips for glasses wearers:
1) Wear contacts for trekking if you are a contact wearer,
2) Pinch the nose piece of the mask tight to your nose to prevent fogging,
3) Pack a de-fogging product as you prepare for your trip and apply just prior to (but not during) your visit,
4) Bring a pair of binoculars, which can be a great way to see the gorillas in detail without the inconvenience of fogging.