Table 2.
Summary of included case control studies on individuals with Alzheimer's disease and mild cognitive impairment.
| References | Country | Sample | Mean MMSE (±SD) | Mean age (±SD) | Sex (M/F) | Eye | Neurocognitive diagnosis |
OCTA
model |
Macular scan size | Parafoveal VD: inner; outer diameter (mm) | Choroidal perfusion density | SCP | DCP | FAZ | NOS score |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Bulut et al. (2018) | Turkey | 26 ADs | 16.92 (±7.39) | 74.23 (±7.55) | 11/15 | S | NIA-AA | RTVue XR Avanti | 6x6 | NA | NA | SCP were significantly lower in AD than controls. | NA | FAZ was significantly enlarged in AD than controls. | 7 |
| 26 Controls | 26.81 (±2.20) | 72.58 (±6.28) | 13/13 | ||||||||||||
| Lahme et al. (2018) | Germany | 36 ADs | 22.32 (±4.45) | 67.97 (±9.3) | 21/15 | S | NIA-AA | RTVue XR Avanti | 3x3 | NA | NA | SCP were significantly lower in AD than controls. | No significant difference. | No significant difference. | 6 |
| 38 Controls | NA | 66.08 (±10.11) | 23/14 | ||||||||||||
| O'Bryhim et al. (2018) | USA | 14 Pre-ADs | NA | 73.5 (±4.7) | 8/6 | P | NA | RTVue XR Avanti | 6x6 | NA | NA | NA | NA | FAZ was enlarged in biomarker (+) eyes compared with biomarker (-) eyes. | 7 |
| 16 Controls | NA | 75.4 (±6.6) | 6/10 | ||||||||||||
| Jiang et al. (2018b) | USA | 12 ADs | NA | 73.3 | NA | P | NIA-AA | Cirrus 5000 Angioplex | 3x3 | NA | NA | SCP were significantly lower in AD than controls. | DCP were significantly lower in AD than controls. | NA | 8 |
| 19 MCIs | NA | 69.6 | NA | ||||||||||||
| 21 Controls | NA | 67.6 | NA | ||||||||||||
| Querques et al. (2019) | Italy | 12 ADs | 20.7 (±3.6) | 72.9 (±7.2) | 4/8 | S | NIA-AA | Cirrus 5000 Angioplex | 3x3; 6x6 | 3;6 | No significant difference. | No significant difference. | No significant difference. | No significant difference. | 7 |
| 12 MCIs | 24.9 (±2.7) | 76.3 (±6.9) | 5/7 | ||||||||||||
| 32 Controls | NA | 71.6 (±5.9) | 17/15 | ||||||||||||
| Haan et al. (2019) | Netherlands | 48 ADs | 23.0 (±3.0) | 65.4 (±8.1) | 25/23 | P | NIA-AA | Cirrus 5000 Angioplex | 6x6 | 1-3; 3-6 | NA | No significant difference. | NA | No significant difference. | 6 |
| 38 Controls | 29.0 (±1.0) | 60.6 (±5.0) | 24/14 | ||||||||||||
| Zhang et al. (2019) | USA | 3 early ADs/13 aMCIs | 26.0 | 73.03 (± 8.24) | 3/13 | P | NIA-AA | RTVue XR Avanti | 3x3 | 1;3 | NA | SCP were significantly lower in early AD/aMCI than controls. | No significant difference. | NA | 7 |
| 16 Controls | NA | 73.60 (±7.69) | 3/13 | ||||||||||||
| Zabel et al. (2019) | Poland | 27 ADs | 20.55 (±5.46) | 74.11 (±5.87) | 6/21 | S | NIA-AA | RTVue XR Avanti | 6x6 | 1;3 | NA | No significant difference. | DCP were significantly lower in AD than controls. | FAZ was significantly enlarged in AD than controls. | 7 |
| 27 Controls | 28.39 (±1.04) | 74.26 (±7.66) | 8/19 | ||||||||||||
| Yoon et al. (2019) | USA | 39 ADs | 20.1 (±5.9) | 72.8 (±7.7) | 13/26 | P | NIA-AA | Cirrus 5000 Angioplex | 3x3; 6x6 | 3;6 | NA | SCP were significantly lower in AD than controls and AD vs. MCI but not between MCI and controls. | NA | No significant difference. | 6 |
| 37 MCIs | 22.6 (±4.7) | 72.8 (±7.7) | 17/20 | ||||||||||||
| 133 Controls | 29.2 (±1.1) | 69.2 (±7.8) | 36/97 | ||||||||||||
| Wu et al. (2020) | China | 18 ADs | 19.67 (±2.45) | 69.94 (±6.39) | 10/9 | P | AD (NINCDS-ADRDA); MCI (Petersen criteria) | RTVue XR Avanti | 6x6 | 1-3; 3-6 | NA | No significant difference. | DCP were significantly lower in AD and MCI than controls. | FAZ was significantly largest in AD, followed by MCI, and lastly controls. | 6 |
| 21 MCIs | 24.76 (±1.09) | 67.81 (±5.96) | 12/9 | ||||||||||||
| 33 Controls | 27.14 (±1.20) | 68.67 (±5.85) | 11/10 | ||||||||||||
| Chua et al. (2020) | Singapore | 24 ADs | 20.3 (±6.1) | 74.9 (±6.0) | 7/17 | P | AD (DSM-IV); MCI (Petersen criteria) | Cirrus 5000 Angioplex | 3x3 | 1;2.5 | NA | SCP were significantly lower in AD and MCI than controls. | DCP were significantly lower in AD than controls. | No significant difference. | 6 |
| 37 MCIs | 23.9 (±6.3) | 77.9 (±6.4) | 21/16 | ||||||||||||
| 29 Controls | 24.8 (±4.8) | 76.7 (±5.3) | 16/13 | ||||||||||||
| Robbins et al. (2021) | USA | 67 ADs | 19.77 (±7.09) | 72.76 (±8.07) | 22/45 | P | NIA-AA | Cirrus 5000 Angioplex | NA | NA | Choroidal vascularity index was significantly less in AD than MCI. | NA | NA | NA | 6 |
| 74 MCIs | 24.45 (±5.85) | 70.04 (±11.53) | 33/41 | ||||||||||||
| 137 Controls | 28.96 (±2.73) | 69.23 (±7.71) | 38/99 | ||||||||||||
| Salobrar-Garcia et al. (2020) | Spain | 17 MCIs | 26.0 | NA | NA | S | MMSE/CDR | Heidelberg Spectralis | NA | NA | NA | NA | NA | No significant difference. | 5 |
| 15 Controls | 30.0 | NA | NA | ||||||||||||
| Criscuolo et al. (2020) | Italy | 27 aMCIs | 26.51 (±1.8) | 73.0 (± 6.0) | 12/15 | S | NIA-AA | RTVue XR Avanti | 6x6 | NA | NA | SCP were significantly lower in MCI than controls. | DCP were significantly lower in MCI than controls. | FAZ was significantly enlarged in MCI than controls. | 7 |
| 29 Controls | 28.03 (±1.3) | 73.1 (± 7.0) | 14/15 | ||||||||||||
| van de Kreeke et al. (2020) | Netherlands | 12 pre -AD Aβ+ | 29.0* | 68.6 (±6.3) | 58/66 | P | TICS-M/CDR | Cirrus 5000 Angioplex | 6x6 | 1-3; 3-6 | NA | Aβ+ participants had significantly higher vessel density than Aβ- individuals in all regions. | No significant difference. | 5 | |
| 111 pre-AD Aβ- | |||||||||||||||
| Wang et al. (2021) | Netherlands | 62 ADs | 19.92 (±4.54) | 71.81 (±7.98) | 27/35 | P | NIA-AA | RTVue XR Avanti | 3x3 | 1;3 | NA | SCP were significantly lower in AD and MCI than controls. | DCP were significantly lower in AD and MCI than controls. | No difference in FAZ among the three groups. | 7 |
| 47 MCIs | 28.04 (±1.90) | 72.73 (±7.75) | 18/29 | ||||||||||||
| 49 Controls | 28.67 (±1.0) | 69.50 (±5.94) | 17/32 | ||||||||||||
| Shin et al. (2021) | Korea | 40 MCIs | NA | 72.8 (±8.6) | 25/15 | P | NIA-AA | Cirrus 5000 Angioplex | 6x6 | 1-3; 3-6 | NA | SCP were significantly lower in MCI than controls. | • No significant difference. • No significant difference. |
FAZ was significantly enlarged in MCI than controls. | 7 |
| 37 Controls | NA | 69.0 (±10.4) | 17/20 | ||||||||||||
| O'Bryhim et al. (2021) | USA | 16 Pre-ADs | NA | 76.29 (±4.66) | NA | P | NA | RTVue XR Avanti | 6x6 | NA | NA | NA | • NA • NA |
FAZ was enlarged in biomarker (+) eyes compared with biomarker (-) eyes. | 7 |
| 19 Controls | NA | 75.21 (±4.13) | NA | ||||||||||||
NA, Not Available; CC, Case–control study; PS, Prospective study; MMSE, Mini-Mental State Examination; NIA-AA, National Institute on Aging and Alzheimer's Association (NIA-AA); NINCDS-ADRDA, National Institute of Neuro- logical, Communicative Disorders and Stroke-Alzheimer Disease and Related Disorders Association; CDR, Clinical Dementia Rating; TICS-M, The modified Telephone Interview for Cognitive Status; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, fourth edition; OCTA, Optical Coherence Tomography Angiography; AD, Alzheimer's Disease; MCI, Mild cognitive impairment; aMCI, Amnestic mild cognitive impairment; Eye; S, OCTA measurements of either single eye were selected; P, OCTA measurements of both eyes were considered; SCP, Superficial capillary plexus; DCP, Deep capillary plexus; FAZ, Foveal avascular zone.
*
Median.