Table 1.

Features of rod osmotic swelling and backscatter increases measured with OCT

	Rod OS		Water influx into rod OS				Backscatter from IS/OS
Strain, N	Length, μm	Increase, μm	Max. rate, μm3⋅s−1	Total, μm3	LP, cm3⋅s−1⋅dyn−1	Pf, cm⋅s−1	Dark, S2OCT × 10−8	Light, S2OCT × 10−8	Ratio
BALB/c, 11	19.3 ± 0.1	2.1 ± 0.1	0.033 ± 0.006	3.2 ± 0.2	1.7 ± 0.1 × 10−14	2.3 × 10−5	0.12 ± 0.01	0.55 ± 0.05	4.9 ± 0.5
C57Bl6/J, 7	21.1 ± 0.6	1.9 ± 0.2	0.032 ± 0.011	2.8 ± 0.2	2.0 ± 0.2 × 10−14	2.8 × 10−5	0.06 ± 0.01	0.22 ± 0.05	3.5 ± 0.4
Gnat1−/−, 10	21.7 ± 1.3	0.007 ± 0.12	—	—	—	—	0.10 ± 0.02	0.08 ± 0.01	0.9 ± 0.1

The first row identifies features of mouse rod OS measured with OCT, the second row identifies measured parameters associated with the feature, and the third row gives the physical units of the latter (where appropriate). Numerical entries are mean ± SEM of data from the experimental paradigm illustrated in Fig. 1 (10% bleaching exposure). Length measurements assumed an average refractive index of 1.410 for the rod OS. Water influx parameters were estimated from fitting the osmo-elastic model (Eq. 1) to rod OS elongation data (e.g., Fig. 1F, red trace), assuming the dark-adapted cytoplasmic volume is 56% of the rod OS envelope volume (Fig. 4 and Osmo-Elastic Model of Light-Induced Rod OS Swelling). For the rod OS diameter of 1.4 μm (61), the cytoplasmic volume of a 20-μm long, dark-adapted mouse rod OS is 17.2 μm³. S²_OCT specifies the backscatter power in instrumental units of the OCT. Hydraulic conductivity (L_P) and water permeability (P_f) were computed for each experiment with Eq. 2, as described in the text.