Table 3.
OQAS-II parameters among the normal, FFK, AK1, and AK2 group.
| NL (n = 21) | FFK (n = 21) | AK1 (n = 21) | AK2 (n = 21) | P | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FFK/NL | AK1/NL | AK2/NL | FFK/AK1 | FFK/AK2 | AK1/AK2 | |||||
| OSI | 0.44 ± 0.18 | 0.61 ± 0.37 | 2.85 ± 2.62 | 9.88 ± 3.86 | 0.815 | 0.001∗ | 0.000∗ | 0.003∗ | 0.000∗ | 0.000∗ |
| MTF cutoff (c/d) | 46.69 ± 6.43 | 38.81 ± 8.93 | 21.97 ± 10.59 | 7.23 ± 4.51 | 0.002∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ |
| SR | 0.27 ± 0.05 | 0.23 ± 0.06 | 0.13 ± 0.05 | 0.06 ± 0.02 | 0.002∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ |
| OV-100 | 1.56 ± 0.21 | 1.29 ± 0.30 | 0.73 ± 0.35 | 0.24 ± 0.15 | 0.002∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ |
| OV-20 | 1.21 ± 0.22 | 0.95 ± 0.26 | 0.49 ± 0.27 | 0.16 ± 0.10 | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ |
| OV-9 | 0.75 ± 0.16 | 0.59 ± 0.17 | 0.29 ± 0.16 | 0.10 ± 0.07 | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ | 0.000∗ |
NL: normal; FFK: forme fruste keratoconus; AK1: stage 1 of the Amsler-Krumeich scales; AK2: stage 2 of the Amsler-Krumeich scales; OSI: object scatter index; MTF cutoff: modulation transfer function cut off; SR: Strehl ratio; OV-100: OQAS values at contrasts of 100%; OV-20: OQAS values at contrasts of 20%; OV-9: OQAS values at contrasts of 9%. ∗P < 0.05 denotes statistical significance.