Auto-aligning slit lamp for eye exams

Unmet Need

At least 2.2 billion people in the world have vision impairment. In 2019, there were 60 million incident cases and 438.4 thousand years lived with disability of eye injury. Almost half of these cases are preventable disease, underscoring the need for accessible diagnostic tools. However, the most common imaging tool in optometry practice, the slit lamp, is currently limited by its need for patient stabilization and its high demand of operator skill. A slit lamp illuminates the eye with adjustable light and subsequently observed for diagnosis. The conventional slit lamp is a tabletop device that requires the patient to be seated upright, their head immobilized by chin and forehead rests. Handheld slit lamps are used when the conventional setup is not possible, such as for bedbound or mobility impaired patients. The operator must manually align the handheld so projected light is focused on the front of the eye, which is often challenging due to ocular movement. There is a need for an improved slit lamp with enhanced accessibility to patients and reduced burden on operators.

Technology

Duke inventors have developed an improved slit lamp device with an auto-aligning system that will streamline examination of patients. Specifically, this auto-aligning slit lamp consists of a dynamic illumination optical system, imaging cameras, and tracking cameras, all mounted on a robotic arm. The optical system uses a liquid crystal display (LCD) scheme to project a slit onto the patient's cornea. The illumination is dynamic, with the system detecting small pupil movement and moving the slit to match it. This dynamic illumination system can stand alone as a handheld slit lamp that compensates for small lateral hand or eye movements. Furthermore, when mounted on the robotic arm, it makes a fully automated slit lamp, where the robotic arm detects and follows large body and head movements. Together, the dynamic illumination system and robotic arm allow for repetitive slit lamp imaging and performing diagnostics without the need for patient restriction or advanced training. This has been demonstrated in a complete prototype. The inventors have also applied similar auto-alignment technology to an optical coherence tomography (OCT) handheld scanner (T-008586).

Advantages

• Accommodates more patients.
• Reduces operator burden.
• Improved accuracy and efficiency.
• Versatile as either a handheld slit lamp or mounted on the robotic arm.
• Dynamic illumination system is lightweight and robust (no moving parts).