The ornamental design for a light treatment apparatus, as shown and described.
1.-3. Light treatment apparatus
1.1 : Right perspective
1.2 : Back
1.3 : Top
1.4 : Left perspective
1.5 : Bottom
1.6 : Front
2.1 : Right perspective
2.2 : Back
2.3 : Top
2.4 : Left perspective
2.5 : Bottom
2.6 : Front
Design 1: fig.1.1 is a right side perspective view of a light treatment apparatus in an open state showing our new design, the broken line illustration of the nose rest forms no part of the claimed design; fig. 1.2 is a rear view thereof; fig. 1.3 is a top view thereof; fig. 1.4 is a left side perspective view thereof; fig. 1.5 is a bottom view thereof; and, fig. 1.6 is a front view thereof; design 2: fig. 2.1 is a bottom right side perspective view of a light treatment apparatus in a closed state showing our new design, the broken line illustration of the nose rest forms no part of the claimed design; fig. 2.2 is a rear view thereof; fig. 2.3 is a top view thereof; fig. 2.4 is a top left side perspective view thereof; fig. 2.5 is a bottom view thereof; and, fig. 2.6 is a front view thereof.