Accessible Light Microscope for Students with Mobility and Visual Impairments

Bradley S. Duerstock, PhD

ABSTRACT

Students with profound mobility impairments are often unable to perform light microscopy by themselves. The ability to independently control a microscope allows students and scientists with disabilities to perform laboratory research by themselves and eliminates the need to rely on classmates or lab assistants for help. Independent microscope operation also provides an active learning experience necessary for better understanding microscopical imaging concepts and histology. An accessible microscopy workstation was developed that allowed students with a range of upper limb mobility impairments to independently control all features of a brightfield and fluorescent light microscope. The PC user interface will be adapted to accommodate different mobility and visual impairments.

Keywords:

light microscopy; accessibility; mobility impairments; science education; low vision

BACKGROUND

Light microscopy is one of the most basic laboratory techniques for a science student or scientist. Microscope usage is fundamental for acquiring an in-depth understanding of cell biology, histology, botany, and materials science - and even optics. The ability to operate a light microscope encourages students with disabilities to take an active part in laboratory experiments and the learning process (1). For a comprehensive educational experience, students with disabilities need to be able to interact with their teacher and classmates, as well as the course material and laboratory equipment (2, 3).

Without the ability to operate a microscope students with disabilities are relegated to reading histology atlases, studying stock micrographs, operating computer simulations, or relying on another to operate the microscope for them. These passive learning activities do help students with disabilities learn histology and cell biology, but they are not substitutes for practical experience. The National Science Education Standards emphasize that hands-on experimental activities are a crucial component of learning (4). The ability to actively explore and interact with scientific concepts and practices is critical to knowledge acquisition and retention (4). Activity-based learning is recommended as a standard of teaching science to disabled and able-bodied students at all educational levels (5, 6, 7, 8, 9, 10). In addition, independent light microscope control is necessary for persons with disabilities to take practical exams by themselves, conduct graduate level research, and ultimately pursue occupations in the scientific, medical, or engineering disciplines. Relying on a laboratory assistant is often expensive and impractical.

Light microscopes have previously been proposed to be adapted to assist persons with disabilities. Enlarged images of microscopical specimens can be digitally projected from a microscope onto a projector screen to aid students with motor and visual impairments. Microscope knobs can be modified to be adjusted by individuals with some degree of hand motor skills (1, 12). However, such accessible adaptations solve one or only a few technical problems and do not employ an integrated approach to control all facets of microscopy through a single input method. Current microscopy systems do not allow students and scientists with little or no upper limb mobility to be able to independently control all aspects of a research-level light microscope.

To solve this problem an integrated accessible microscopy workstation, called AccessScope, was developed to allow students and scientists with disabilities to operate a light microscope independently. AccessScope allows students with mobility disorders, including head and spinal cord injuries, rheumatoid arthritis, poliomyelitis, and multiple sclerosis, to fully control a light microscope and other microscopy functions. Once the slide autoloader is filled with slides the user does not require further assistance. Preliminary investigation has shown that modifications to the AccessScope system could also allow students with low vision to independently operate AccessScope, including those with retinitis pigmentosa, macular degeneration, diabetic retinopathy, and nystagmus.

METHODOLOGY

Microscope Workstation Design

The initial design of the prototype integrated microscopy workstation was based on the ability to use a personal computer (PC) interface to control all features of the microscope including loading slides. The PC is adaptable to accommodate different user's preferences and disability by employing different input devices and assistive technology (AT) software. During this project different AT software were made available according to individual participants' wishes. Different input devices including a mouse, trackball, keyboard, and speech recognition were also available for participants.

Figure 1. d (Click image for larger view)

The major hardware component of AccessScope was an Olympus® BX61® research light microscope with motorized objective nosepiece, condensor, filter wheel, illuminator, and Z focus drive (Fig. 1A). The microscope communicated with the PC through a RS232C connection. A motorized stage by Ludl ® Electronics Products (Fig. 1B) was attached to the microscope to translate in the X and Y axes. Assembled with the stage was a bulk slide autoloader (Fig. 1C) that mechanically loads slides onto the stage controlled by the user through the PC. The autoloader holds up to fifty slides. A digital camera mounted on top of the microscope (Fig. 1D) displayed images of the slide specimens to the computer monitor (Fig. 1E).

A commercial microscopy program was initially used to control each part of the AccessScope workstation. This AccessScope control software will be replaced with a novel application to specifically accommodate students with mobility and visual impairments. Like the current application, the new AccessScope program will run on Microsoft® Windows® and control all facets of the microscope workstation. The new application, however, will be designed specifically for users with hand and arm mobility impairments and users with visual impairments. The AccessScope application will be compliant with other accessibility applications, such as typing, voice recognition, screen magnifier, and text reading software.

The design of the graphical user interface for the software application will comply with Section 508 accessibility guidelines (10, 12). Specialists in software assistive technology for users with low vision and motor impairments will assist in the design of the AccessScope graphical user interface (GUI). Issues concerning low or impaired vision will include a loss of visual acuity, distorted vision, light sensitivity, limited field of vision, and lack of contrast. Motor impairments generally result in the loss or weakness of fine or gross motor control or both in the upper extremities. Software controls will accommodate these different mobility impairments. Design critiques from disabled participants will also be incorporated.

Recruitment and Evaluation of Participants

Seven participants with a range of mobility impairments have evaluated the AccessScope thus far (Table 1). In total twenty University-level students who are partially-sighted and mobility-impaired will participate in this study. A combination of qualitative and quantitative assessments will be used to evaluate the effectiveness of AccessScope for students with disabilities. A repeated measures design will be used in which participants will serve as their own controls to rate the usability of AccessScope. Participants compare conventional microscopical methods, including studying databases of slide images or histology atlases, that they have used in past science classes with performing microscopy with AccessScope. Measures of student performance for ease of use and accuracy of readings will be collected. To control for practice effects, students will perform microscopy on the same tissue samples and perform the same tasks. The order of control and experimental conditions will be counterbalanced among participants. In addition, students will be interviewed to identify aspects of each condition that were perceived as challenging or advantageous.

RESULTS

Figure 2. d (Click image for larger view)

Of the seven subjects tested, all were able to successfully perform common microscopical tasks without human assistance (Fig. 2). Subjects were asked to turn on the microscope and light source, load specific slides, position individual specimens, focus, change objectives, and acquire images of slide specimens without any assistance except verbal directions.

The features participants stated they appreciated the most were the ability to; view specimens on the computer monitor instead of through the eyepieces, operate the microscope using a pointing device and joystick, change different slides using the slide autoloader, and adjust the height of the workstation table. Features of AccessScope that participants suggested to be modified were to change the style or shape of the joystick for controlling stage movement and to increase the size of the workstation table.

Participants' accessibility needs to independently use the prototype AccessScope were made to the PC instead of to the microscopy hardware. Each user's needs were accommodated by repositioning and choosing their preferred pointing device and AT software, modifying the AccessScope control GUI, and adjusting the height of the workstation table (Table 2).

In a questionnaire participants with mobility impairments described their experiences with a conventional light microscope. Two out of seven subjects claimed they could satisfactorily operate a microscope. However, all subjects stated their disability was a hindrance in operating it efficiently.

Five participants discussed what aspects of conventional light microscope operation were particularly difficult for them to accomplish. All five of these participants used a wheelchair or scooter. Four out of the five participants stated that viewing specimens through microscope eyepieces was a major obstacle to using a light microscope because of the position of the microscope eyepieces. The other participant stated that visual difficulties, including double vision and nystagmus, in addition to mobility impairments made using binocular eyepieces difficult. All five participants found that loading slides and positioning the stage of a standard microscope was difficult because of lacking the necessary dexterity.

DISCUSSION

Participants with a range of upper limb mobility impairments were able to successfully perform common microscopy activities without assistance using AccessScope. All subjects stated in the past they had intentionally tried to avoid laboratory-intensive classes because of their disability. Participants also stated that the prospect of being required to use certain job-specific equipment had dissuaded them from pursuing a particular course of study or occupational choice.

We believe AccessScope is the first microscope system to allow persons with severe upper limb mobility impairments to independently control all aspects of microscopy. AccessScope is sophisticated to accommodate disciplinary requirements that would satisfy graduate-level histology and cell biology courses and flexible enough for incoming undergraduate biology students to medical pathologists. AccessScope can be used for brightfield and fluorescence microscopy, image acquisition and analysis, and cell and tissue morphometry.

An improved control software application will be developed to be more accessible for persons with motor or visual impairments. The new application will also provide remote access and multiple-user sharing of a single AccessScope workstation from a computer network or the internet. Remote control promotes distance learning and equipment sharing between several users to reduce hardware costs. Less expensive versions of AccessScope using digital microscopes will also be investigated.

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