ɪf ðɪ ˈaɪ wʌz ɪŋkˈeɪpəbəl ʌv kəntɹˈækʃən, wiː wʊd ˈoʊnli biː ˈeɪbəl tə sˈiː ɪn wˈʌn dᵻɡɹˈiː ʌv lˈaɪt ænd wiː wʊd nˌɑːt biː ˈeɪbəl tə dˌɪfɚɹˈɛnʃɪˌeɪt ðə dˈɪstəns ʌv lˈaɪt ɹᵻflˈɛktɪŋ fɹʌm nˌɪɹ ænd fˈɑːɹ ˈɑːbdʒɛkts.
If the eye was incapable of contraction, we would only be able to see in one degree of light and we would not be able to differentiate the distance of light reflecting from near and far objects.