Table S2.

Attenuation factors arising from rod waveguide properties, alignment, and other morphological features of the rod

Factor	Fold attenuation	Description	Comments and source
i	1.3	Fraction of 860-nm power in the core of the mouse rod waveguide	(12, 15)
ii	∼2	Variation across the OCT B-scan field	Beam axis vs. photoreceptor waveguide axis
iii	∼2	Variation across experiments in optimal alignment of mouse	System optical axis vs. mouse eye optical axis
iv	5–6	Apodization by optical system pupil	Assuming rod N.A. = 0.25
v	2–5	Ultrastructure of the IS/OS (OS base): inhomogeneity and surface tilt	Fig. 5; Δz ≤ 0.4 μm vs. λ = 0.86 nm
vi	∼2	Axial distribution of the IS/OS (Fig. S1) vs. the axial psf
All	∼100−300	Total attenuation