The mean age of the studied cases was 57.16 ± 6.81 years ranging from 44–66 year in group A and 61 ± 6.87 years ranging from 56–71 year in group B. The studied cases included 8 males (40%) and 12 females (60%) in group A and 7 males (35%) and 13 females (65%) in group B.
The mean diabetes duration was 13.23 ± 4.47 ranging from 7–21 year in group A and 10.71 ± 5.69 ranging from 4–24 year in group B.
The mean preoperative HbA1c level was 7.98 ± 0.92 ranging from 6.1–9.2 in group A and 8.36 ± 1.17 ranging from 5.6–9.7. in group B.
The mean preoperative IOP in group A was 15.36 ± 3.17 ranging from 12–21 mm.Hg. and 16.44 ± 2.18 ranging from 11–20 mm.Hg. in group B.
The differences among the studied groups regarding baseline characteristics were statistically insignificant.
BCVA
The mean preoperative BCVA in our patients was 0.17 ± 0.08 (range, 0.1–0.4) in group A and 0.21 ± 0.10 (range, 0.1–0.4) in group B (table 1).
The mean postoperative BCVA was 0.27 ± 0.14 (range, 0.1–0.4) (Delta change 58.8 ± 51.21) in group A and 0.38 ± 0.21 (range, 0.2–0.5). (Delta change 81.0 ± 73.6) in group B.
The postoperative BCVA significantly increased compared with preoperative one in both groups. (p-value = 0.002 in group A and < 0.001 in group B)..
The differences among the studied groups in pre and post BCVA were statistically insignificant.
By the end of our study, we had 13 eyes (65%) improved in BCVA in group A compared to 14 eyes (70%) in group B while there was 6 eyes (30%) in group A did not improve compared to 3 eyes (15%) in group B, only 1 eye (5%) in group A worsened compared to 3 eyes (15%) in group B
Table (1)
Comparison between Group A and Group B according to BCVA.
BCVA
|
Group A
(n = 20)
|
Group B
(n = 20)
|
Test
|
p-value
|
Pre
|
|
|
|
|
Mean ± SD
|
0.17 ± 0.08
|
0.21 ± 0.10
|
T=-1.448
|
0.156
|
Range
|
0.1–0.4
|
0.1–0.4
|
Post
|
|
|
|
|
Mean ± SD
|
0.27 ± 0.14
|
0.38 ± 0.21
|
T = 1.949
|
0.059
|
Range
|
0.1–0.4
|
0.2–0.5
|
Paired t-test
|
4.059
|
5.627
|
|
|
p-value
|
0.002*
|
< 0.001**
|
|
|
Mean Diff.
|
0.10 ± 0.11
|
0.17 ± 0.14
|
Z = 1.758
|
0.087
|
Delta Change%
|
58.8 ± 51.21
|
81.0 ± 73.6
|
Z = 1.107
|
0.275
|
Using: t-Independent Sample t-test; z-Mann Whitney test; p-value > 0.05 NS |
CMT
The mean preoperative CMT in our patients was 493.50 ± 124.27 µm ranging from 309 µm to 803 µm in group A and 502.35 ± 103.31 µm ranging from 334 µm to 748 µm in group B.
The mean postoperative CMT was 315.90 ± 67.31 µm ranging from 219 µm to 499 µm in (Delta change − 36.0 ± 11.13) group A and 299.10 ± 58.46 µm ranging from 184 µm to 422 µm (Delta change − 40.5 ± 9.8) in group B.
There was a significant reduction of CMT postoperatively compared with preoperative values in both groups (p-value < 0.001).
The differences among the studied groups in pre and post CMT were statistically insignificant.
Table (2)
Comparison between Group A and Group B according to CMT.
CMT
|
Group A
(n = 20)
|
Group B
(n = 20)
|
Independent t-test
|
p-value
|
Pre
|
|
|
|
|
Mean ± SD
|
493.50 ± 124.27
|
502.35 ± 103.31
|
-0.245
|
0.808
|
Range
|
309–803
|
334–784
|
Post
|
|
|
|
|
Mean ± SD
|
315.90 ± 67.31
|
299.10 ± 58.46
|
0.843
|
0.405
|
Range
|
219–499
|
148–422
|
Paired t-test
|
-9.368
|
-12.256
|
|
|
p-value
|
< 0.001**
|
< 0.001**
|
|
|
Mean Diff.
|
-177.60 ± 84.78
|
-203.25 ± 74.2
|
-1.018
|
0.315
|
Delta Change%
|
-36.0 ± 11.13
|
-40.5 ± 9.8
|
-1.357
|
0.183
|
Using: t-Independent Sample t-test; p-value > 0.05 NS |
MF-ERG
The mean Preoperative P1 amplitude in ring (1 + 2) (nV/degree2) was 32.15 ± 6.86 ranging from 18 to 44 in group A and 35.50 ± 8.15 ranging from 20 to 50 in group B.
The mean postoperative P1 amplitude in ring (1 + 2) was 41.10 ± 7.15 ranging from 30 to 55 (Delta change 27.80 ± 22.67) in group A and 40.85 ± 7.26 ranging from 23 to 51 (Delta change 15.1 ± 13.63) in group B.
Compared to the preoperative P1 amplitude values the difference was significant in both groups (p-value < 0.001)
The mean Preoperative P1 latency (ms) in ring (1 + 2) was 50.30 ± 7.36 ranging from 39 to 68 in group A and 49.55 ± 7.65 ranging from 38 to 66 in group B.
The mean post operative P1 latency (ms) in ring (1 + 2) was 36.40 ± 8.17 ranging from 22 to 50 (Delta change − 27.60 ± 14.64) in group A and 39.25 ± 8.50 ranging from 27 to 61 (Delta change − 20.8 ± 8.93) in group B.
Compared to the preoperative P1 latency values the difference was significant in both groups (p-value < 0.001)
The differences among the studied groups in pre and post amplitude and latency were statistically insignificant.
Table (3)
Comparison between Group A and Group B according to MF-ERG.
MF-ERG
|
Group A
(n = 20)
|
Group B
(n = 20)
|
Test
|
p-value
|
Amplitude
|
|
|
|
|
Pre
|
|
|
|
|
Mean ± SD
|
32.15 ± 6.86
|
35.50 ± 8.15
|
T=-1.407
|
0.168
|
Range
|
18–44
|
20–50
|
Post
|
|
|
|
|
Mean ± SD
|
41.10 ± 7.15
|
40.85 ± 7.26
|
T = 0.110
|
0.913
|
Range
|
30–55
|
23–51
|
Paired t-test
|
7.035
|
6.364
|
|
|
p-value
|
< 0.001**
|
< 0.001**
|
|
|
Mean Diff.
|
8.95 ± 5.69
|
5.35 ± 3.76
|
Z=-2.361
|
0.024*
|
Delta Change%
|
27.80 ± 22.67
|
15.1 ± 13.63
|
Z=-2.147
|
0.038*
|
Latency
|
|
|
|
|
Pre
|
|
|
|
|
Mean ± SD
|
50.30 ± 7.36
|
49.55 ± 7.65
|
T = 0.316
|
0.754
|
Range
|
39–68
|
38–66
|
Post
|
|
|
|
|
Mean ± SD
|
36.40 ± 8.17
|
39.25 ± 8.50
|
T=-1.081
|
0.287
|
Range
|
22–50
|
27–61
|
Paired t-test
|
-7.574
|
-10.760
|
|
|
p-value
|
< 0.001**
|
< 0.001**
|
|
|
Mean Diff.
|
-13.90 ± 8.21
|
-10.30 ± 4.28
|
Z = 1.739
|
0.090
|
Delta Change%
|
-27.60 ± 14.64
|
-20.8 ± 8.93
|
Z = 1.773
|
0.084
|
Using: t-Independent Sample t-test; z-Mann Whitney test; |
p-value > 0.05 NS; *p-value < 0.05 S |
Significant correlation was found among postoperative changes of the macular thickness, BCVA, amplitude & latency of the mf-ERGs and HbA1c.
Table (4): Correlation between CMT Change with all parameters, using Pearson Correlation Coefficient in all patients.
Parameters in all patients
|
CMT Change
|
r-value
|
p-value
|
Age (years)
|
-0.113
|
0.436
|
Duration of DM (years)
|
0.024
|
0.868
|
HbA1c
|
0.865
|
0.423
|
IOP
|
-0.202
|
0.158
|
BCVA Change Pre and Post
|
-0.288
|
0.043*
|
MF-ERG [Amplitude] Change Pre and Post
|
-0.870
|
< 0.001**
|
MF-ERG [Latency] Change Pre and Post
|
0.888
|
< 0.001**
|
r-Pearson Correlation Coefficient, p-value > 0.05 NS; *p-value < 0.05 S; **p-value < 0.001 HS |
This table shows statistically significant negative correlation between CMT Change with BCVA Change and MF-ERG [Amplitude] Change, while HbA1c and MF-ERG [Latency] Change show significant positive correlation.
Only one eye (0.05%) in group A had an iatrogenic break that was treated intaoperatively by endo-laser photocoagulation with air tamponade post operative without development of postoperative retinal detachment, no iatrogenic breaks occurred in group B.
In terms of postoperative complication, mild vitreous haemorrhage developed in 2 cases. 1 case (0.05%) in group A and 1 case (0.05%) in group B, with spontaneous resolution at 2 month postoperatively.
At the end of study (after 3 months) we had 5 cases developed cataract; 3 out of 17 phakic eyes in group A (17%) and 2 out of 14 phakic eyes in group B (14%).