Association between the number of visual fields and the accuracy of future prediction in eyes with retinitis pigmentosa

Abstract

Purpose: To evaluate the minimum number of visual fields (VFs) required to precisely predict future VFs in eyes with retinitis pigmentosa (RP).

Methods: A series of 12 VFs (Humphrey Field Analyzer 10-2 test (8.9 years in average) were analysed from 102 eyes of 52 patients with RP. The absolute error to predict the 12th VF using the prior 11 VFs was calculated in a pointwise manner, using the linear regression, and the 95% CI range was determined. Then, using 3-10 initial VFs, next VFs (4th to 11th VFs, respectively) were also predicted. The minimum number of VFs required for the mean absolute prediction error to reach the 95% CI was identified. Similar analyses were iterated for the second and third next VF predictions. Similar analyses were conducted using mean deviation (MD).

Results: In the pointwise analysis, the minimum number of VFs required to reach the 95% CI for the 12th VF was five (first and second next VF predictions) and six (third next VF prediction). For the MD analysis, three (first and second next VF predictions) and four (third next VF prediction) VFs were required to reach 95% CI for the 12th VF.

Conclusions: The minimum number of VFs required to obtain accurate predictions of the future VF was five or six in the pointwise analysis and three or four in the analysis with MD.

Keywords: eye (globe); field of vision; retina.

Figure 1

Association between the absolute prediction error and the number of VFs used in the prediction (PW sensitivity). The Y-axis shows the absolute prediction error when predicting the first, second or third next VF. (A) First next VF prediction. The X-axis shows the number of VFs used in the prediction. For instance, X=12 suggests the absolute prediction error when the 12th VF was predicted using VF_1–11. Values are illustrated as the mean and SE. Prediction calculations were conducted using 102 eyes up to X=11, 72 eyes for X=12, 59 eyes for X=13, and 38 eyes for X=14. The grey zone shows the 95% CI of the absolute prediction error when predicting VF₁₂ using VF_1–11. (B) Second next VF prediction. The X-axis shows the number of VFs used in the prediction. For instance, X=13 suggests the absolute prediction error when the 15th VF was predicted using VF_1–13. Values are illustrated as the mean and SE. Prediction calculations were conducted using 102 eyes for up to X=10, 72 eyes for X=11, 59 eyes for X=12, and 38 eyes for X=13. The grey zone shows the 95% CI of the absolute prediction error when predicting VF₁₂ using VF_1–10. (C) Third next VF prediction. The X-axis shows the number of VFs used in the prediction. For instance, X=12 suggests the absolute prediction error when the 15th VF was predicted using VF_1–12. Values are illustrated as the mean and SE. Prediction calculations were conducted using 102 eyes for up to X=9, 72 eyes for X=10, 59 eyes for X=11, and 38 eyes for X=12. The grey zone shows the 95% CI of the absolute prediction error when predicting VF₁₂ using VF_1–9. OLSLR, ordinary least square regression; PW, pointwise; VF, visual field.

Figure 2

Association between the absolute prediction error and the number of VFs used in the prediction (MD). The Y-axis shows the absolute prediction error when predicting the first, second or third next VF. (A) First next VF prediction. The X-axis shows the number of VFs used in the prediction. For instance, X=12 suggests the absolute prediction error when the 12th VF was predicted using VF_1–11. Values are illustrated as the mean and SE. Prediction calculations were conducted using 102 eyes for up to X=11, 72 eyes for X=12, 59 eyes for X=13, and 38 eyes for X=14. The grey zone shows the 95% CI of the absolute prediction error when predicting VF₁₂ using VF_1–11. (B) Second next VF prediction. The X-axis shows the number of VFs used in the prediction. For instance, X=13 suggests the absolute prediction error when the 15th VF was predicted using VF_1–13. Values are illustrated as the mean and SE. Prediction calculations were conducted using 102 eyes for up to X=10, 72 eyes for X=11, 59 eyes for X=12, and 38 eyes for X=13. The grey zone shows the 95% CI of the absolute prediction error when predicting VF₁₂ using VF_1–10. (C) Third next VF prediction. The X-axis shows the number of VFs used in the prediction. For instance, X=12 suggests the absolute prediction error when the 15th VF was predicted using VF_1–12. Values are illustrated as the mean and SE. Prediction calculations were conducted using 102 eyes for up to X=9, 72 eyes for X=10, 59 eyes for X=11, and 38 eyes for X=12. The grey zone shows the 95% CI of the absolute prediction error when predicting VF₁₂ using VF_1–9. OLSLR, ordinary least square regression; PW, pointwise; VF, visual field.