  Deep learning is currently the state-of-the-art for automated detection of
referable diabetic retinopathy (DR) from color fundus photographs (CFP). While
the general interest is put on improving results through methodological
innovations, it is not clear how good these approaches perform compared to
standard deep classification models trained with the appropriate settings. In
this paper we propose to model a strong baseline for this task based on a
simple and standard ResNet-18 architecture. To this end, we built on top of
prior art by training the model with a standard preprocessing strategy but
using images from several public sources and an empirically calibrated data
augmentation setting. To evaluate its performance, we covered multiple
clinically relevant perspectives, including image and patient level DR
screening, discriminating responses by input quality and DR grade, assessing
model uncertainties and analyzing its results in a qualitative manner. With no
other methodological innovation than a carefully designed training, our ResNet
model achieved an AUC = 0.955 (0.953 - 0.956) on a combined test set of 61007
test images from different public datasets, which is in line or even better
than what other more complex deep learning models reported in the literature.
Similar AUC values were obtained in 480 images from two separate in-house
databases specially prepared for this study, which emphasize its generalization
ability. This confirms that standard networks can still be strong baselines for
this task if properly trained.
