# Artificial Intelligence-Based System for Retinal Disease Diagnosis
## 4 Discussion of Results  
We conduct more than 100 experiments with different combinations and values of input variables. The experiments' results help to identify the key determinants and factors (markers) for each disease. Surface plots for each of the four diagnoses are shown in Figure 7. In the presence of one or another input variable, the diagnosis (O1...O4) will be established with a higher probability; that is, these input variables act as certain markers of one or another diagnosis. Based on the correlation matrix obtained as a result of testing the model for more than 100 different situations, it was found that the input variables I7, I8, I10, I16, I17, I18, I19, I21, I23, I27, I28, I31, I32, I33, I35, I36, I37, I38 and I39 have medium correlation with the output variables O1, O2, O3 and O4 (correlation coefficient r from 0.4 to 0.67), and the input variable I24 has a high correlation with O2 (correlation coefficient r more than 0.68). Correlation matrix is shown in Figure 8.  
Based on a detailed analysis of the correlation matrix, it was found that the diagnosis O1 is established for the variables I16 (r = \(-\)0.47), I19 (r = \(-\)0.59) and I35 (r = \(-\)0.46). Consequently, the presence or absence of diabetic retinopathy is determined by the amplitude of the b-wave of the maximum ERG, the peak latency of the a-wave of the maximum ERG and the threshold of electrical sensitivity. Figure 7: Surface plots for the diagnoses and its key predictors (hsv colormap is used): (**a**) I\({}_{16}\), I\({}_{19}\) and O\({}_{1}\); (**b**) I\({}_{7}\), I\({}_{21}\) and O\({}_{2}\); (**c**) I\({}_{2}\), I\({}_{20}\) and O\({}_{3}\); (**d**) I\({}_{10}\), I\({}_{20}\) and O\({}_{4}\). The diagnosis O2 is established for variables I7 (r = 0.42), I10 (r = \(-\)0.44), I17 (r = \(-\)0.6), I19 (r = \(-\)0.58), I21 (r = \(-\)0.57), I23 (r = \(-\)0.51), I24 (r = \(-\)0.68), I27 (r = \(-\)0.56), I31 (r = 0.55), I33 (r = 0.49), I37 (r = \(-\)0.53) and I38 (r = 0.42). Therefore, the presence or absence of age-related macular degeneration is determined by the following parameters: difficulty reading, presence of detachment in the fellow eye, peak latency of the b-wave of maximum ERG, peak latency of the a-wave of maximum ERG, latency of the a-wave of cone ERG, amplitude of the b-wave of rod ERG, amplitude of the a-wave of rod ERG, latency of N1 mf-ERG, time of N95 PERG, liability of the optic nerve, amplitude of the a-wave of local ERG and latency of the a-wave of local ERG. The diagnosis O3 is established for the variables I10 (r = 0.53), I16 (r = \(-\)0.54), I28 (r = \(-\)0.47), I32 (r = 0.64), I36 (r = \(-\)0.43) and I39 (r = \(-\)0.37). Therefore, the presence or absence of retinoschisis is determined by the following parameters: the presence of detachment in the fellow eye, the amplitude of the b-wave of maximum ERG, the amplitude of PERG, the threshold of electrical sensitivity, the amplitude of N1 mf-ERG and the amplitude of the b-wave of local ERG. The diagnosis O4 is established for the variables I8 (r = 0.46), I18 (r = \(-\)0.418), I19 (r = \(-\)0.57), I32 (r = \(-\)0.41) and I33 (r = \(-\)0.45). Therefore, the presence or absence of retinal detachment is determined by surgical intervention, the amplitude of the b-wave of maximum ERG, the peak latency of the a-wave of maximum ERG, the threshold of electrical sensitivity and the ability of the optic nerve. Thus, the main determinants (markers) of the diagnosis O1 (diabetic retinopathy) are objective data obtained from the electrophysiological complex--variables I16 (maximum ERG, b-wave amplitude), I19 (peak latency of the a-wave of maximum ERG) and I35 (amplitude of rhythmic ERG at 30 Hz).