fɔːɹ ðˈɪs, fˈʌŋkʃənəl ˈæspɛkts kˈʌm ˌɪntʊ plˈeɪ: ðə stˈoːɹɪdʒ ʌv ɹˈɛtɪnəl ænd ðɪ ɐdˈæpʃən ʌvðə ɹɪˈækʃən spˈiːd.
For this, functional aspects come into play: the storage of retinal and the adaption of the reaction speed.