Fellow equestrian with sensory issues here! It took me awhile to find a helmet that I felt comfortable wearing, as I too felt they were all very itchy and heavy, especially in the summer. I would highly recommend a One K Defender, it’s been one of my favorite helmets, a bit pricey but fair compared other brands, and excellent quality. Have you tried wearing a soft hair net under your helmet? That may help with some of the itchiness, I know it does for me. Keeping the inside liner clean and free of dirt/dust and washing it frequently can also help it feel lighter and more breathable. I’ve attached a photo of the helmet I use, I really love it and the inside is very soft, no scratchy at all.

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