Table 2.
Comparison of the OCTA parameters between NDR and control groups before and after the hyperoxic challenge.
| Groups | P value | ||
|---|---|---|---|
| NDR | Control | ||
| Parafoveal VD at SCP | |||
| Before (mean ± SD) | 44.64 ± 4.62 | 49.32 ± 3.95 | <0.001 |
| After (mean ± SD) | 44.93 ± 6.44 | 48.75 ± 4.82 | 0.029 |
| Difference | 0.29 ± 3.41 | −0.58 ± 4.96 | 0.51 |
| P value | 0.708 | 0.61 | |
|
| |||
| Parafoveal VD at DCP | |||
| Before (mean ± SD) | 49.36 ± 5.32 | 53.06 ± 3.06 | 0.006 |
| After (mean ± SD) | 49.71 ± 5.42 | 50.17 ± 3.56 | 0.742 |
| Difference | 0.35 ± 6.75 | −2.89 ± 4.19 | 0.034 |
| P value | 0.819 | 0.006 | |
|
| |||
| FAZ (mm2) | |||
| Before (mean ± SD) | 0.285 ± 0.073 | 0.27 ± 0.087 | 0.536 |
| After (mean ± SD) | 0.332 ± 0.114 | 0.28 ± 0.083 | 0.093 |
| Difference | 0.05 ± 0.12 | 0.01 ± 0.03 | 0.173 |
| P within | 0.095 | 0.153 | |
|
| |||
| Flow index, outer retina | |||
| Before (mean ± SD) | 1.338 ± 0.623 | 1.204 ± 0.368 | 0.396 |
| After (mean ± SD) | 1.15 ± 0.583 | 1.155 ± 0.423 | 0.972 |
| Difference | −0.19 ± 0.37 | −0.05 ± 0.47 | 0.281 |
| P within | 0.033 | 0.647 | |
Groups were compared using generalized estimating equation to correct for intereye associations. P value equal or less than 0.05 is significant and was calculated using the paired t-test. OCTA, optical coherence tomography angiography; NDR, no diabetic retinopathy; VD, vessel density; SCP, superficial capillary plexus; DCP, deep capillary plexus; FAZ, foveal avascular zone.