Table 5 Advantages and disadvantages of different imaging methods for screening and assessment of DR severity
Imaging methods | Advantages | Disadvantages |
|---|---|---|
Stereoscopic 7-field | Stereopsis for detecting DME, NVE, NVD, pre-retinal hemorrhages, and vitreous hemorrhages | Time-consuming process and requires highly training photographers for capturing images [15, 16] Requires stereo viewer while grading images in order to appreciate stereo effect 14 images are captured |
Montage | Viewing 7F area in a single shot while maintaining original monoscopic images Less photographs are taken (7 total) | Time-consuming in constructing montage and requires highly training technician Lack of stereopsis |
Monoscopic 7-field | Less photographs are taken (7 total) | Lack of stereopsis |
Mosaic | Less photographs are taken (9 total) | Lack of stereopsis Uneven transition between adjacent fields [22] Does not entirely cover 7F area although covers larger retinal area [22] |
Ultra-widefield | Only one photograph is taken Covers much larger retinal area Viewing retinal area in a single shot | Lack of stereopsis Lower sensitivity in detecting certain retinopathy lesions [26, 27] Semirealistic fundus images [15] |