The sunvisors, even the light gray ones, in the EC225 are sufficient sun protection for my eyes. Even before I was forced to wear glasses, I almost never used sunglasses in the military and simply 'squinted' my eyes to reduce glare. I found that sunglasses irritated me and sometimes gave me a headache.
The stems of my prescription glasses don't let extra noise into the earphones, as the pads have settled around the stems to make a full seal. We are issued with reusable individually shaped earplugs which do a fantastic job of filtering out unwanted noise, so additional noise reduction offered by helmets is not an issue for us.
Sunburn also isn't an issue when flying over the North Sea. I have a skin type which is highly intolerant of strong sunlight and I use SPF 50 in sunny latitudes. In 30 summers here, I've never gotten sunburned in a helicopter.
So, hearing problems can't be blamed on a combination of earphones and sunglasses; properly fitted earplugs take care of that. Sunburn is a non-factor for North Sea pilots. All that leaves is head protection in the event of a crash. About 40 years of North Sea oil exploration history tells us that not one life might have been saved by the wearing of helmets. Q.E.D.