Centre for Sensors, Instruments and Systems Development

Universitat Politècnica de Catalunya

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Ophthalmic instrumentation for tear film evaluation based on corneal reflex degradation

The tear film is the first surface of the eye which is in contact with the air. When its normal function is altered dry eye appears, a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. Dry-eye has high prevalence, up to 30%, and which is expected to increase due to the use of contact lenses, LASIK and all sorts of displays.

There are several tests in clinical practice for dry eye diagnosis. Despite the wide use of those techniques in clinical practice, there is general agreement of their limitations as being subjective and invasive. In this sense in the last years a big effort has been made to develop objective and non-invasive methods for dry eye diagnosis based in new technologies.However, up to date no gold-standard exists for the diagnosis of dry eye, and some of the methods based in new technologies are unfeasible in clinical environment as cannot be adopted to daily clinical practice, where inexpensive and easy-to use tools are needed.

In the last years our research group has propposed a new method for tear film evaluation by means of corneal reflex image degradation analysis, a simple technique based on photonics. When the tear film is in good condition the image of coherent light reflected on the cornea, is regular and of good quality. However, when the tear film breaks up, the corneal reflex degrades. By means of the corneal reflex image degradation, our method evaluates the tear film and could be used on dry eye diagnosis. Up to date, our research group has done basic research on the field, developed the method, built a pre-prototype and carried out measurements in laboratory and clinical conditions. Moreover, the method has been tested in the assesment of contact lens comfort, evaluating the tear film stability in the contact lens. Fruits of this labor, we have done international communications of the scientific progresses, published a paper on an international journal and patented the method.

The final goal of the project is to develop an instrument for tear film stability assesment based on corneal reflex degradation and focused to daily clinical practice, where inexpensive and easy to use tools are required. Our research group has been working on this objective for the last three years. During this time basic research has been done, the methodology been develop, a pre-prototype been built and laboratory and clinical measurements performed with patients. The actual prototype and methodology are suitable for laboratory conditions and, although some tests have been done in clinical practice, work is still required in order to be feasible in operational (clinical) environment.

This project has been co-financed by the European Union through the European Regional Development Fund (ERDF) and has the support of the Secretariat of Universities and Research of the Department of Business and Knowledge of the Generalitat de Catalunya
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