Ocular discomfort has primarily been attributed to contact lens wear, refractive surgery, meibomian gland dysfunction and aging. It is something that we all experience from time to time; however, it could be an early symptom of more serious ocular diseases, such as keratoconus, shingles or herpes.
Efforts to diagnose, treat and understand the underlying causes have been hindered by a lack of suitable methods to quantify ocular sensitivity. Traditional instruments are either inaccurate, difficult to use or not generally available.
Dr Klaus Ehrmann, Director of Technology, Brien Holden Vision Institute (BHVI), and associates have developed a new instrument, based on the liquid jet concept, to measure ocular sensitivity, which can potentially enable practitioners to quickly measure discomfort and inform their diagnosis and treatment recommendations.
The instrument does this by propelling small droplets of sterile liquid through a micro-valve onto the surface of the eye. The sensitivity threshold is established by increasing the intensity of the stimulus until the patient reports a positive response. Mechanical, chemical and thermal stimulation is achieved by adjusting the properties of the liquid. The dedicated hardware and custom written software control all the operating parameters, including ejection pressure, precise position targeting, temperature and droplet size.
The instrument conveniently attaches to any slit lamp and is easy to use by unskilled operators. A complete measurement takes 2-3 minutes. With both the patient and the operator being masked to the applied stimuli, more reliable results can be achieved. This new method of corneal stimulation opens a wide range of new applications, ranging from detecting abnormalities in corneal sensation to diagnosing corneal diseases and monitoring the effectiveness of treatment options.