Background: The two most important characteristics of the natural tear are its chemophysical properties and the continuity of its delivery. The chemical characteristics of tears are very difficult to reproduce since they contain more than 200 different components. In severe dry eyes - due to their relative short residence - manual application of artificial tears from small bottles to the eye has to be performed every 5-10 min, while at night no lubrication at all is provided. Previously, for continuous lubrication of the ocular surface, dacryoreservoirs attached to spectacles or placed in pockets of the patient's clothes were used, but were often complicated by infection. A new option is the implantable pump dacryoreservoir.
Material and methods: In 21 patients with a Schirmer test without anaesthesia of <2mm in 5 min, a Medtronic 60-ml reservoir was implanted into a pocket under the subcutaneous tissues of the anterior abdominal wall and connected to a silicone catheter that ascended subcutaneously along the chest, neck and temple to the upper conjunctival fornix. The results of this procedure and complications associated with the implantation of reservoirs in general - as evaluated on the basis of a Medline search - are presented.
Results: Postoperatively all patients reported a dramatic improvement of dry eye symptoms. Slit-lamp microscopy revealed a substantially prolonged break-up time and a reduction of signs of ocular surface disease such as superficial punctuate keratopathy and conjunctival hyperaemia. A penetrating keratoplasty was successfully performed in 2 eyes with an implanted dacryoreservoir and remained clear throughout the follow-up of up to 3.5 years. No infections of the catheter reservoir were observed. Prominent parts of the catheter induced skin ulceration, but no infection, in 2 patients which was managed successfully by removal of the catheter, systemic antibiotics and subsequent re-implantation of a new catheter. A literature review showed that infection is not a frequent problem with implantable and external reservoirs.
Conclusion: At present, this is the only safe and effective method able to maintain a continuous lubrication of the ocular surface with artificial tears, and the only one that allows corneal, conjunctival or limbal transplantations in severe dry eyes.