The biostatistics has gained significant importance in recent years, being one of the mainstays of current scientific research. It has a series of concepts and rules that must be understood to carry out or analyze an article. In this review we will discuss some of main tools utilized in works of interest in ophthalmology, its applications and limitations.
Biostatistics/methods; Statistical distributions; Data Interpretation, statistical
| Normal | Keratoconus | |||||
|---|---|---|---|---|---|---|
| Mean ± Standard Deviation | Range | Mean ± Standard Deviation | Range | p-value* * Student's t test | ||
| K1 | 42.68 ± 1.47 | 39.5 - 46.7 | 49.35 ± 7.64 | 38.6 - 71.6 | < 0.001 | |
| K2 | 43.66 ± 1.58 | 39.8 - 48.2 | 51.58 ± 9.1 | 42.6 - 77.5 | <0.001 | |
| CCT | 550 ± 35 | 444 - 632 | 460 ± 57 | 283 - 548 | <0.001 | |
| TP | 544 ± 35 | 443 - 629 | 443 ± 60 | 254 - 542 | <0.001 | |
| Astig Axis | 97 ± 71 | 1 - 180 | 76 ± 64 | 0 - 179 | 0.12 | |
| Test | III Group | Normal Group (no disease) |
|---|---|---|
| Positive for Disease | Correct decision, True Positive (TP) | Type II or β error, False Negative (FN) |
| Negative for Disease | Type I or α False Positive (FP) | Correct decision, True Negative (TN) |
| Cut-off point | Sensitivity (%) | Specificity (%) |
|---|---|---|
| < 283 | 0 | 100 |
| <= 435 | 20.45 | 100 |
| <= 444 | 20.45 | 99.12 |
| <= 456 | 34.09 | 99.12 |
| <= 459 | 34.09 | 98.25 |
| <= 460 | 36.36 | 98.25 |
| <= 462 | 36.36 | 97.37 |
| <= 477 | 61.36 | 97.37 |
| <= 479 | 63.64 | 96.49 |
| <= 483 | 63.64 | 95.61 |
| <= 493 | 68.18 | 95.61 |
| <= 496 | 68.18 | 93.86 |
| <= 498 | 72.73 | 93.86 |
| <= 501 | 72.73 | 91.23 |
| <= 502 | 75 | 91.23 |
| <= 504 | 77.27 | 90.35 |
| <= 505 | 79.55 | 88.6 |
| <= 506 | 79.55 | 87.72 |
| <= 507 | 81.82 | 87.72 |
| <= 508 | 81.82 | 86.84 |
| <= 509 | 88.64 | 85.96 |
| <= 516* | 93.18 | 85.96 |
| <= 523 | 93.18 | 78.07 |
| <= 524 | 95.45 | 77.19 |
| <= 529 | 95.45 | 72.81 |
| <= 532 | 97.73 | 71.05 |
| <= 547 | 97.73 | 53.51 |
| <= 548 | 100 | 53.51 |
| <= 632 | 100 | 0 |
| AUC | ||
|---|---|---|
| K1 | 0.865 | |
| K2 | 0.859 | |
| CCT | 0.939 | |
| TP | 0.957 |
| K1 | K2 | CCT | TP | |
| K1 | 0.85 | 0.049 | 0.036 | |
| K2 | 0.037 | 0.009 | ||
| CCT | 0.003 | |||
| TP |
