Online learning with virtual slides, how our members are teaching in response to COVID-19

August 25, 2021

In early 2020, in response to growing concern about the threat posed by the novel coronavirus sars-cov-2 (COVID-19), many universities cancelled face-to-face classes for their students and moved to online learning. For those teaching histology and pathology, virtual slides were an essential part of their online classes.

Some of our academic members were already incorporating Slice into online learning or for students at remote sites, but COVID-19 meant that all face-to-face classes had to be moved online. We asked some of our members to share how they have been using Slice for online learning during the pandemic.

Running online classes

Virtual slides are an essential part of online learning in microscopy-based disciplines including histology, pathology, haematology and cytopathology. Slice can be used for both synchronous and asynchronous online teaching and provides an authentic and interactive way of teaching microscopy compared to the use of static images.

During online lectures, our academic members used videoconferencing tools such as Microsoft Teams or Zoom, and alternated the screensharing of Slice images and layers with the  screensharing of Microsoft PowerPoint slides or similar. For synchronous practical sessions, academics used video conferencing tools and their institutional LMS (Blackboard, Moodle or Canvas) to share links to Slice images and annotation layers. When teaching asynchronously (e.g. prereading or offline learning tasks), academics shared links with their students through the LMS or other programs such as H5P, Padlet or EdX, or incorporated them directly into learning materials through links embedded in images in presentations or PDFs.


An important part of online teaching with virtual slides is the ability to mark regions of slides to point out features to students. Academics have two options when teaching with virtual slides in online classes:

1. Use the screen annotation tools provided within screensharing software, or

2. Use the Slice annotation tool.

Both methods have advantages and disadvantages and are used for different purposes. Many of our academics used a mixture of both methods during live screensharing sessions. Our members have shared below some tips that may help you identify which one works best for the different types of online teaching you are facilitating.

Within live classes, while guiding students through the features of virtual slides, academics often used the screen annotation tools provided within screen sharing software or additional tools such as Epic Pen or Ink2Go. This was particularly the case when they needed to respond rapidly to student questions, because the annotations were flexible and transient, allowing them to draw or highlight whatever they wanted and erase just as quickly. However, notes made using the screen annotation tools were not often saved.

Many academics also made use of pre-annotated Slice layers in their live teaching sessions. They reported that they generally make these layers prior to any teaching session rather than doing it live in class. This was because they preferred to commit some time to create the layers that they would present and share with students. The Slice annotation tool allows our academic and student members to highlight areas of the slide and make notes. Annotation layers were created by academics to:

• Highlight features to draw attention to while teaching, avoiding the need to search for hard-to-find features within a live session

• Prepare a “professional looking” set of notes, compared to the rough notes created with the use of screen annotation tools

• Generate a permanent set of shareable notes, compared to transient screen annotations

• Be easily duplicated and altered to suit other student cohorts or additional purposes

• Be modified year after year

• Share with students before class to help them prepare or after class to review what was covered. Example pre- and post-class layers are viewable by BEST Network members.

It's worth noting that in Slice some images already have “public layers" that you can copy and edit to suit your own purpose – while saving time in drawing detailed annotations around key features (example viewable by members:

Active learning

Student learning is improved when they are given the opportunity to be actively involved in the learning process, interacting with the material, synthesising what they have heard and solving problems (Bonwell, 1991). By annotating, students are required to identify features on slides, to name them and to summarise information about the feature. The notes they create are held in context of the feature’s position on the slide, making them easier to review and edit than a screenshot.

Some of the ways our members facilitate active learning during online sessions include:

• Giving students time to make their own layers and notes during synchronous classes as a record of finding features or while watching a walkthrough of the slide by their teacher. All layers are private until shared and most members indicated that they did not usually ask their students to share their layers.

• Giving students the opportunity to take control of the screen share and to show the layer they have annotated live online (e.g. in Microsoft Teams), and to prompt them to build on these layers in real-time by asking them to identify other features that were not annotated.

• Asking students to summarise their learnings as annotation layers as revision for homework.

Handling questions

Students may have questions about the slides or the appearance of structures. Instead of students taking a screenshot and sharing that with their teachers, Slice enables them to mark up the image, identifying the feature they have questions about. A direct link to the annotation, at a suitable magnification, allows that layer to be shared privately with their tutor, course co-ordinator or friends.

Synchronous online sessions can give students the opportunity to share the link to their annotation within the chat function or to share their screen and ask their questions. The greatest benefit is that those answering the question can then view the feature at any magnification, in context of where it is located within the tissue rather than be restricted to a single view.

Collaborative layers

After creating an annotation layer, members can be invited to join that layer and annotate together for a group activity. Some of our members use collaborative layers on Slice as an exercise for students during live online sessions, interspersed with students annotating individually or reviewing academic annotations. Once all students have logged in and joined the layer, they can place pins on features as requested by their teacher. The colour coding of annotations creates heat maps of student responses. Student annotations can also be reviewed with the entire group anonymously, and the teacher or peers can provide effective feedback in real-time.

Slice also facilitates annotating in smaller student groups. Academics or students can create layers and chose whether the participants are anonymous or whether their names are shown. By giving participants the ability to see other annotations as they are created, peer-to-peer learning can be facilitated.

A special thank you to Dr Martin Weber, Professor Nicholas Hawkins, Professor Nicodemus Tedla, Dr Claire Aland and Dr Noelia Roman for sharing how they use Slice for online learning. Dr Martin Weber has previously discussed how he uses Slice for remote learning by Medicine students who attend Rural Clinical Schools.

Slice has been designed to be a very flexible tool for learning and it is suited to both face-to-face and online learning. It facilitates a variety of ways for students to engage with microscopy content so that classes can employ a few activities to keep attention high throughout the class. If you have any questions about using Slice in your classes, please get in contact with me at New members are welcome to trial using Slice with their students.


1. Bonwell, C.; Eison, J. (1991). Active Learning: Creating Excitement in the Classroom AEHE-ERIC Higher Education Report No. 1. Washington, D.C.: Jossey-Bass. ISBN 978-1-878380-08-1.

Photo by Chris Montgomery on Unsplash

Stephanie Dowdell