ADVANCED IMAGING

A compact, computational solid-state system being developed as a tool for examining and imaging the anterior segment offers many advantages and advanced capabilities compared to the ophthalmic slit lamp, according to Shantanu Sinha BS, who presented the technology at the 2015 annual meeting of the Association for Research in Vision and Ophthalmology in Denver, USA.

“Our platform is a less expensive, low-complexity, portable system and can be operated by less skilled technicians. Its features make it attractive for use in settings where cost and access to medical care are issues, and to the best of our knowledge, it is the only portable system that can generate a complete 3D model of the anterior segment,” said Mr Sinha, speaking on behalf of his colleagues in the Camera Culture Group, MIT Media Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.

The system is comprised of a pico projector, which outputs a computationally generated slit of light, simplified optics that collimate and focus the slit onto the eye, and a 60fps RGB camera fitted with a beam splitter that images the anterior chamber in high definition. The examination is completed in less than five seconds, and the image is transferred to a computer, where it can be reviewed later by an ophthalmologist.

The prototype device measures 120mm long x 60mm wide. Like a conventional slit lamp, it has an 80° field of view. However, because it is under computational control, the system can project any pattern of light on to the eye, generate a 3D model of the anterior segment, and provide quantitative metrics and topographical maps.

GREAT UTILITY

Therefore, Mr Sinha and colleagues envision that the system has great utility for not only imaging external, corneal and anterior segment pathologies, but also for generating quantitative information to guide management.

For example, it could measure the distance between the apex of a pterygium and the central visual axis and quantify irregular astigmatism associated with the lesion. By quantifying light scatter, it could grade cataract opacity.

Topographic imaging capabilities would allow its use for identifying and characterising corneal ectatic disorders and facilitating complicated contact lens fittings. In addition, it is capable of measuring corneal thickness and posterior corneal surface radius of curvature at an infinite number of locations.

The Camera Culture Group is collaborating with the LV Prasad Eye Institute, Hyderabad, India, to develop, validate, and eventually deploy this technology. They hope to initiate clinical trials with their prototype in 2015, and by mid-2016, to have
a clinic-ready device suitable for seeking regulatory approvals.

Shantanu Sinha:
sssinha@mit.edu