When looking for good youth sports sunglasses, there are several factors to consider to ensure they provide proper eye protection, comfort, and durability. Here are some key features to look for when selecting youth sports sunglasses:

1. UV Protection: The primary function of sports sunglasses is to protect the eyes from harmful UV rays. Look for sunglasses that provide 100% UV protection (UV400 or higher) to shield young eyes from both UVA and UVB rays.

2. Impact Resistance: Sports sunglasses for youth should be made from impact-resistant materials, such as polycarbonate lenses, to withstand potential accidents or impacts during sports activities.

3. Lens Material: Choose lenses that are scratch-resistant to ensure longevity. Some sports sunglasses also have interchangeable lenses for different lighting conditions, which can be a useful feature.

4. Wraparound Design: A wraparound design provides better coverage and protection from sunlight and debris, and it helps to reduce peripheral glare.

5. Durability: Look for sturdy and well-built frames, preferably made of materials like nylon or TR90, which are lightweight and durable. Rubberized or grippy nose pads and temple tips can help keep the sunglasses in place during activities.

6. Anti-Fog Coating: If the sunglasses will be used in conditions where fogging is a concern (such as during cold weather sports), consider sunglasses with anti-fog coatings to maintain clear vision.

7. Comfort and Fit: Proper fit is crucial for sports sunglasses. Look for adjustable features like nose pads and temple tips to ensure a secure and comfortable fit. Some youth sports sunglasses come with adjustable straps to keep them in place during high-intensity activities.

8. Ventilation: Adequate ventilation can help prevent fogging and ensure comfort during sports. Some sunglasses have built-in vents to improve airflow.

9. Polarized Lenses (Optional): Polarized lenses can help reduce glare from reflective surfaces like water or pavement, which can be beneficial for some sports. However, they may not be suitable for all sports, so consider the specific needs of the young athlete.

10. Lens Tint: The lens tint should be appropriate for the specific sport and lighting conditions. For example, amber or brown lenses can enhance contrast in overcast conditions, while gray lenses are versatile for various lighting conditions.

11. Safety Certification: Check if the sunglasses have been certified for sports use, especially if they are intended for high-impact activities like baseball, basketball, or skiing.

12. Style and Color: While not as critical as the above factors, choosing a style and color that the young athlete likes can help ensure they wear the sunglasses consistently.

It's essential to involve the youth athlete in the selection process to ensure a comfortable fit and that their specific needs are met. Additionally, consulting with an optometrist or eyewear specialist can provide valuable guidance in finding the right sports sunglasses for a young athlete's particular sport and visual requirements.