Fig. 1
a Amsler chart, case 1. A central scotoma, due to a prefoveal floater, extending to 2.2° × 1.3° of visual angle on the Amsler chart held at about 30 cm distance such that one square corresponds to 1°. b Optical coherence tomography, case 1. A prefoveal floater is seen on the right (cSLO). The 25 vertical green lines correspond to subsequent OCT B-scans on an approximate 30° field. The distance between the individual lines calculates to 1.2°. The floater measures about 3.6° × 1.2° on the cSLO image. This prefoveal floater corresponds to the mirror image shown on the Amsler chart in a. d Central scotoma in case 2. The small, relative central scotoma makes it difficult to read small print text messages on his smart phone. The text for the city of “London” is obscured whilst focusing on the words “nice sunny”. e–f Serial OCT was taken over a 9-month period. One small prefoveal floater remains in exactly the exact same place at three-month follow-up visits. g The very small prefoveal floater in case 3 casts a dense shadow in the OCT image, which is not visible on the sCLO image on the right, but can be seen on the OCT B-scan on the left (colour figure online)