Table 2.
Principal studies comparing central corneal thickness (CCT) in diabetic and non-diabetic patients.
| Authors, Years |
Study Design | Imaging Method | Eyes (n) | CCT (µm) | Conclusions | ||
|---|---|---|---|---|---|---|---|
| DM | Controls | DM | Controls | ||||
| Suraida et al., 2018 [86] |
CS | AS-OCT | DM = 100 NoDR = 50 NPDR = 50 |
50 | 524.60 ± 28.74 529.26 ± 33.88 |
493.12 ± 67.08 | Diabetic patients appear to have significantly thicker CCT regardless the retinopathy status (p < 0.001) |
| Yusufoglu et al., 2022 [87] | P, CS | AS-OCT | 72 | 72 | 544.33 ± 31.20 | 533.77 ± 24.45 | The CCT was statistically significantly thicker in diabetic patients than in the controls (p = 0.025) |
| Canan et al., 2020 [88] |
P, CS | AS-OCT SST UP |
NoDR = 49 NPDR = 30 PDR = 17 NoDR = 49 NPDR = 30 PDR = 17 NoDR = 49 NPDR = 30 PDR = 17 |
521.71 ± 27.58 528.20 ± 29.16 516.94 ± 34.25 568.10 ± 32.5 567.57 ± 35.49 554.47 ± 25.95 551.1 ± 29.64 556.07 ± 31.18 544.18 ± 36.33 |
No correlation between CCT and the severity of retinopathy (p > 0.05) Better correlation for OCT and UP. |
||
| Lee et al., 2006 [93] |
CS | UP | 200 ≤10y = 111 >10y = 89 |
100 | 588.2 ± 2.7 582.2 ± 3.7 595.9 ± 4.2 |
567.8 ± 3.8 | Diabetic patients show significantly higher CCT differences compared to controls (p < 0.05) DM of over 10 years’ duration showed thicker corneas (p < 0.05) |
| Özdamar et al., 2010 [92] | CS | UP | DM = 100 NoDR = 29 NPDR = 48 PDR = 23 |
145 | 564 ± 30 565 ± 32 558 ± 31 582 ± 23 |
538 ± 35 | The CCT of diabetic patients is thicker when compared with non-diabetic patients (p = 0.001) Differences between DM subgroups are not statistically significant (p = 0.056) |
| Su et al., 2008 [94] |
CS | UP | 748 | 2491 | 547.2 ± 1.2 | 539.3 ± 0.7 | Thicker corneas in patients with DM (p < 0.001) |
| Galgauskas et al., 2016 [97] | P, CS | NCSM | 123 | 120 | 566.7 ± 35.7 | 550.0 ± 56.4 | CCT is significantly higher in diabetic patients (p < 0.05) |
| El-Agamy et al., 2020 [98] |
P, CS | NCSM | DM 2 = 57 | 45 | 545.61 ± 30.39 | 539.42 ± 29.22 | No significant difference in CCT between diabetic and control groups (p = 0.301) |
| Inoue et al., 2002 [100] |
CS | UP | DM 2 = 99 | 97 | 538 ± 36 | 537 ± 38 | CCT is not increased in type II DM (p = 0.90) |
| Urban et al., 2013 [101] |
CS | NCSM | DM 1 = 123 | 124 | 550 ± 30 | 530 ± 33 | CCT is increased in children and adolescents with DM (p < 0.0001) |
| Storr-Paulsen et al., 2014 [102] | P, CS | NCSM | 107 | 128 | 546 ± 7 | 538 ± 5 | Diabetic patients show a significant increase in CCT (p < 0.05) |
| Ramm et al., 2020 [105] |
P, CS | Pentacam Corvis ST |
59 | 57 | 552.6 ± 33.2 553.4 ± 35 |
552 ± 36.6 558 ± 38.6 |
No significant increase in CCT in diabetic patients (p = 0.923 and p = 0.511 with Pentacam and Corvis, respectively) |
AS-OCT: anterior segment optical coherence tomography; CS: cross-sectional; DM: diabetes mellitus; DR: diabetic retinopathy; NCSM, noncontact specular microscope; NPDR: non-proliferative diabetic retinopathy; P: prospective; PDR: proliferative diabetic retinopathy; SM: specular microscope; SST: slit-scanning topographer; UP: ultrasonic pachymeter.