We would like to congratulate the team of Kelly and associates on a brilliant study, and we agree with the idea that efforts need to be focused on teaching direct ophthalmoscopy.

This valuable procedure could save lives (in the case of papilledema) and/or the patient’s vision (in the case of diabetic retinopathy or glaucoma).

We also noticed that most physicians do not have the appropriate training during medical school and/or do not retain that knowledge.

Models that simulate real situations are of value in teaching, as well as in diagnostic and even therapeutic maneuvers. The efficacy of these models depends on the skill transfer from the bench to real life and on retention over months and years.

A low-cost model that can stimulate students to learn the physical principles of the direct ophthalmoscope while they participate in its construction was developed by the Medhacker team of the Ocular Bioengineering Laboratory (Ophthalmology Department, Paulista School of Medicine–UNIFESP [Sao Paulo, Brazil]).

The model consists of a cardboard box that creates a dark space and allows for different pupil sizes, which creates different difficulty levels. This simple feature, which is not presented in the published paper, proved to be related to the speed of feature recognition by doctors and students.

We also included a glass sphere that simulates the enlargement of the image produced by the human eye, allowing the use of high-definition (900 dpi) photographs with actual-size optic discs.

Knowing this, the students can easily understand the optical principles when they see a word written inside of the box and realize that the word is not inverted and bigger, for example. Any retinal image could be used in the model to illustrate different diseases and their stages.

The design of the model gives the students a chance to move their heads to observe the entire retinal image, making the scenario more realistic. It is also possible to associate a contact lens with the glass sphere to create different types of ametropia.

In our study, we increased the level of difficulty to make the students more interested in the examination technique and in the learning process itself. The students also felt safer when performing the actual examination with real patients after utilizing the model with different retinal images.