Participant Demographics
Five participants were enrolled in this single center study under the supervision of a single vitreoretinal surgeon. All recruitment, surgeries and follow up visits were conducted at Stony Brook University Hospital and its affiliated sites (Stony Brook, New York). Demographics, diagnosis, age at implantation, implanted eye, axial length and the visual acuity at presentation are shown in Table 1.
Table 1. Participant Demographics at Baseline (N=5)
No. of participants
|
5
|
Age at time of implantation (yrs)
|
69 [53-75]
|
Sex (M)
|
3 (60%)
|
Sex (F)
|
2 (40%)
|
Retinal degeneration diagnosis:
|
|
Leber congenital amaurosis
|
1 (20%)
|
Retinitis pigmentosa
|
4 (80%)
|
Bare light perception
|
5 (100%)
|
Implanted Eye (OS)
|
3 (60%)
|
Implanted Eye (OD)
|
2 (40%)
|
Axial length of implanted eye (mm)
|
23.0 [21.37-23.73]
|
Median [range] or N (%)
Movement of the Implant’s Electrode Array on the Retina over Time
The position of electrode array at M1, M3, M6, Y1 & Y2 is shown in Table 2. A one-way repeated measures ANOVA was performed to determine if there was statistically significant change in the mean movement of the implant changed over time (Figure 2). Mauchly’s Test of Sphericity indicated that the assumption of sphericity had been violated for measures of length AB, X2(9) = 26.872, p = 0.005 and therefore, degrees of freedom were corrected using Greenhouse-Geisser estimated of sphericity ɛ = 0.279. A one-way repeated measures ANOVA revealed that there was no statistically significant difference in distance of length AB overtime (M1 to M24) (F = 0.196, p = 0.705). Bonferroni’s test for multiple comparisons found that there was a significant difference in the change in distance overtime between patients between M3 and M6 (p = 0.025).
Mauchly’s Test of Sphericity indicated that the assumption of sphericity was not violated for measures of angle 𝛾 over time, X2(9) = 10.652, p = 4.08 and therefore, we assumed sphericity. A one-way repeated measures ANOVA revealed that there was a statistically significant change of angle 𝛾 overtime (M1 to M24) (F = 3.527, p = 0.030). Bonferroni’s test for multiple comparisons was done, but it did not show a significant difference in the change in distance between patients.
Mauchly’s Test of Sphericity indicated that the assumption of sphericity was not violated for measures of angle 𝜟 over time, X2(9) = 10.966, p = 0.385 and therefore, we assumed sphericity. A one-way repeated measures ANOVA revealed that there was no statistically significant change of angle 𝜟 overtime (M1 to M24) (F = 1.797, p = 0.179). Bonferroni’s test for multiple comparisons was done but did not show a significant difference in the change in distance between patients.
Mauchly’s Test of Sphericity indicated that the assumption of sphericity had been violated for measures of angle 𝜶 over time, X2(9) = 26.844, p = 0.005 and therefore, degrees of freedom were corrected using Greenhouse-Geisser estimated of sphericity ɛ = 0.308. A one-way repeated measures ANOVA revealed that there was no statistically significant difference in distance of angle 𝜶 overtime (M1 to M24) (F = 0.507, p = 0.546). Bonferroni’s test for multiple comparisons was done but did not show a significant difference in the change in distance between patients.
Mauchly’s Test of Sphericity indicated that the assumption of sphericity was not violated for measures of angle 𝜷 over time, X2(9) = 10.330, p = 0.433 and therefore, we assumed sphericity. A one-way repeated measures ANOVA revealed that there was no statistically significant change of angle 𝜷 overtime (M1 to M24) (F = 2.556, p = 0.079). Bonferroni’s test for multiple comparisons was done but did not show a significant difference in the change in distance between patients.
Table 2. Position of electrode array at M1, M3, M6, Y1, & Y2
Length AB (µm)
Patient
|
M1
|
M3
|
M6
|
Y1
|
Y2
|
1
|
4699.0
|
4749.8
|
4978.4
|
4927.6
|
6070.6
|
2
|
7721.6
|
7594.6
|
7747.0
|
7569.2
|
7518.4
|
3
|
6731.0
|
6553.2
|
6807.2
|
6654.8
|
5816.6
|
4
|
7721.6
|
7442.2
|
7543.8
|
7505.7
|
7632.7
|
5
|
7213.6
|
7366
|
7594.6
|
7353.3
|
7162.8
|
Average
|
6817.36
|
6741.16
|
6934.2
|
6802.12
|
6840.22
|
Angle 𝜶 (degrees)
Patient
|
M1
|
M3
|
M6
|
Y1
|
Y2
|
1
|
78.487
|
78.323
|
76.211
|
75.655
|
70.81
|
2
|
54.471
|
55.712
|
55.877
|
54.69
|
54.876
|
3
|
38.707
|
39.189
|
39.308
|
39.643
|
38.534
|
4
|
15.796
|
16.538
|
17.567
|
23.587
|
21.25
|
5
|
36.439
|
37.41
|
37.85
|
37.961
|
36.978
|
Average
|
44.78
|
45.4344
|
45.3626
|
46.3072
|
44.4896
|
Angle 𝜷 (degrees)
Patient
|
M1
|
M3
|
M6
|
Y1
|
Y2
|
1
|
84.387
|
83.948
|
83.082
|
83.271
|
87.474
|
2
|
97.598
|
94.05
|
91.652
|
91.9
|
92.42
|
3
|
117.924
|
118.456
|
119.707
|
116.334
|
117.997
|
4
|
155.874
|
152.895
|
155.252
|
146.523
|
149.271
|
5
|
122.231
|
121.585
|
118.866
|
119.244
|
119.31
|
Average
|
115.6028
|
114.1868
|
113.7118
|
111.4544
|
113.2944
|
Angle 𝛾 (degrees)
Patient
|
M1
|
M3
|
M6
|
Y1
|
Y2
|
1
|
17.126
|
17.729
|
20.707
|
21.074
|
21.716
|
2
|
27.931
|
30.238
|
32.471
|
33.41
|
32.704
|
3
|
23.369
|
22.355
|
20.985
|
24.023
|
23.469
|
4
|
8.33
|
10.567
|
7.181
|
9.89
|
9.479
|
5
|
21.33
|
21.005
|
23.284
|
22.795
|
23.712
|
Average
|
19.6172
|
20.3788
|
20.9256
|
22.2384
|
22.216
|
Angle 𝜟 (degrees)
Patient
|
M1
|
M3
|
M6
|
Y1
|
Y2
|
1
|
28.936
|
35.352
|
34.789
|
34.226
|
39.783
|
2
|
-37.126
|
-41.952
|
-44.068
|
-43.516
|
-44.599
|
3
|
47.003
|
45.433
|
52.836
|
46.701
|
54.716
|
4
|
32.373
|
30.683
|
33.573
|
31.017
|
37.504
|
5
|
-38.873
|
-43.603
|
-40.862
|
-40.687
|
-38.748
|
Average
|
6.4626
|
5.1826
|
7.2536
|
5.5482
|
9.7312
|
In conclusion, repeated measures ANOVA showed that there was statistically significant change of the optic disc-tack-surgical handle angle (𝛾) (M1 to M24) (F = 3.527, p = 0.030). It showed that there was a significant change in the distance of length AB overtime between patients from M3 to M6 (p=0.025). However, there was no significant change in distance between the optic disc and the surgical handle (length AB) over the two-year span (F = 0.196, p = 0.705). There was also no significant change in angle 𝜟 (the angle to the horizontal of the image), angle 𝜶 (tack-optic disc-surgical handle), and angle 𝜷 (optic-disc-surgical handle-tack). The estimated marginal means of the angles and lengths of each measurement are shown in Figure 2.