Table 1.

Optical sensitivity S, calculated at the level of the ganglion cell matrix, for a range of species. When possible a range of estimation per species is given based on the lowest and highest ganglion cell density. Note that the highest ganglion cell density gives the lowest sensitivity S and vice versa. For all species, we fixed the photoreceptor coefficient of absorption k at 0.035 µm⁻¹, the average for vertebrates [36]. For fish species, we used the diameter of the lens for A and Matthiessen's ratio to calculate f (f = 1.275A). l, Photoreceptor outer segment length; A, pupil or lens diameter; f, focal length; N, ganglion cell density; d, diameter of a ganglion cell's dendritic field; n.a., not available.

species	l (μm)	A (mm)	f (mm)	N (×103 cells mm−2)	d (μm)	S (μm2 sr)	refs
lanternfishes
Bolinichthys longipesd	117a	1.8	2.3	3.4–14.9	9–19	32–140	[32,33]
Electrona rissod	64a	3.4	4.3	1.4–8.0	13–30	54–308	[32,33]
Lampanyctus alatusd	52	1.3	1.7	3.2–19.6	8–20	21–126	[32,33]
Myctophum brachygnathumd	91a	3.3	4.2	1.1–10.6	11–34	44–421	[32,33]
Notoscopelus kroeyerid	37	2.7	3.4	1.1–6.0	15–34	58–317	[32,33]
Symbolophorus rufinusd	78a	2.8	3.6	2.0–11.2	11–25	40–226	[32,33]
other teleosts
Platytroctes apuse	150	5.1	6.5	n.a.–26.2	7–n.a.	18–n.a.	[39,40]
Lepidocybium flavobrunneumd	148a	16.0	20.4	0.1–0.6	46–113	801–4804	[37]
Makaira nigricansc,d	57	19.0	24.2	0.1–1.6	28–113	261–4174	[41]
sharks
Etmopterus luciferd	52	5.4	6.9	n.a.–25.3	22–n.a.	159–n.a.	[42]
Etmopterus spinaxd	51	7.1	9.1	n.a.–10.7	35–n.a.	377–n.a.	[42]
Etmopterus splendidusd	69	3.8	4.8	n.a.–20.5	25–n.a.	215–n.a.	[42]
Squaliolus aliaed	48	3.1	4.0	n.a.–38.9	18–n.a.	101–n.a.	[42]
Triaenodon obesusc,d	31	9.1	10.3	n.a.–15.2	29–n.a.	265–n.a.	[43]
Orectolobus ornatusc	23	5.7	7.3	n.a.–16.2	28–n.a.	165–n.a.	[43]
Hemiscyllium ocellatumc	35	4.5	5.7	n.a.–23.7	23–n.a.	114–n.a.	[43]
human
Homo sapiens	30	8b	16.7	n.a.–38	6–n.a.	3.1–n.a.	[35,38]

^aOuter segment length doubled by the presence of a tapetum lucidum.

^bPupil diameter at night-time.

^cEpipelagic.

^dMesopelagic.

^eBathypelagic.