Table 3.
The Effect of Radiation Dose–Volume Parameters on Ophthalmologic Tests for Chiasm.a
| Visual Tests | Median Score | Odds Ratio | Confidence Interval (95% CI) | P Value |
|---|---|---|---|---|
| Visual acuity | ||||
| V55 <50% vs ≥50% | 1.0 vs 0.3 | 13.33 | 1.39-127.57 | .008 |
| Dmean <50 Gy vs ≥50 Gy | 1.0 vs 0.7 | 1.63 | 1.13-2.36 | .003 |
| D5 <55 Gy vs ≥55 Gy | 1.0 vs 0.7 | 1.41 | 1.09-1.82 | .037 |
| Dmax <60 Gy vs ≥60 Gy | 1.0 vs 0.8 | 1.46 | 1.10-1.95 | .019 |
| RNFL thickness | ||||
| Dmean <50 Gy vs ≥50 Gy | 90 vs 93 | 1.00 | 0.23-4.30 | 1.00 |
| Dmax <60 Gy vs ≥60 Gy | 94 vs 89 | 0.58 | 0.12-2.78 | .49 |
| Visual field | ||||
| V55 <50% vs ≥50% | 2 vs 3 | 4.23 | 4.50-39.87 | .180 |
| Dmean <50 Gy vs ≥50 Gy | 2 vs 3 | 8.51 | 0.90-80.02 | .035 |
| D5 <55 Gy vs ≥55 Gy | 2 vs 3 | 3.50 | 0.63-19.23 | .137 |
| Dmax <60 Gy vs ≥60 Gy | 2 vs 3 | 5.62 | 0.44-22.53 | .102 |
| Contrast sensitivity | ||||
| V55 <50% vs ≥50% | 1 vs 3 | 3.00 | 0.75-11.86 | .112 |
| Dmean <50 Gy vs ≥50 Gy | 1 vs 3 | 7.00 | 1.59-30.80 | .007 |
| D5 <55 Gy vs ≥55 Gy | 1 vs 3 | 2.00 | 0.47-8.46 | .343 |
| Dmax <60 Gy vs ≥60 Gy | 1 vs 3 | 5.00 | 1.19-20.92 | .023 |
| VEP latency | ||||
| V55 <50% vs ≥50% | 101 vs 113 | 7.91 | 1.71-36.63 | .005 |
| Dmean <50 Gy vs ≥50 Gy | 97 vs 110 | 9.35 | 1.71-51.03 | .005 |
| D5 <55 Gy vs ≥55 Gy | 99 vs 110 | 3.78 | 0.69-20.51 | .109 |
| Dmax <60 Gy vs ≥60 Gy | 99 vs 107 | 5.10 | 0.94-27.54 | .045 |
| VEP amplitude | ||||
| V55 <50% vs ≥50% | 8.5 vs 5.0 | 1.16 | 0.25-5.33 | .845 |
| Dmean <50 Gy vs ≥50 Gy | 9.3 vs 5.2 | 2.5 | 0.51-12.13 | .248 |
| D5 <55 Gy vs ≥55 Gy | 7.6 vs 5.6 | 1.0 | 0.20-4.95 | 1.00 |
| Dmax <60 Gy vs ≥60 Gy | 8.9 vs 6.7 | 1.37 | 0.28-6.70 | .693 |
Abbreviations: CI, confidence interval; OR, odds ratio; RNFL, retinal nerve fiber layer; VEP, visual evoked potential.
a Visual acuity: 1.0: normal, <1.0: abnormal; visual field: grade 2: peripheral defects outside the central 30° field, grade 3: defects located in the central 30° field; contrast sensitivity: grade 1: normal, grade 3: under the normal line beginning from low spatial frequencies (1 cycle/degree) for each eye. VEP latency: 106 ± 3 milliseconds; VEP amplitude: 9 ± 4 µV; odds ratio: cross tabulations were prepared, and odds ratios were calculated using the formula, OR = a × d/b × c.