Dr. Eldridge began an interesting thread this past week regarding ocular surface disease in glaucoma patients. He reminded us that dry eye disease can often be silent in patients after chronic administration of BAK preservatives have reduced corneal sensitivity:
An important corollary to this story comes from a study done by Dr. Antoine Labbé at the Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts in Paris. Specifically, he showed that:
“Tear osmolarity was increased in patients treated for glaucoma or OHT, particularly in those using multiple preserved eyedrops.”
Moreover, he showed that the increase in osmolarity was directly related to the number of instillations of preserved eye drops per day.
These data suggest that managing tear osmolarity is an important adjunct to traditional glaucoma therapy. Hyperosmolarity alone has been shown to cause inflammation, apoptosis, and is associated with fluctuations in vision and a loss of lubrication from the endogenous proteoglycans found on the ocular surface. As such, Dr. Labbé and his colleagues suggest that:
“The evaluation of the ocular surface of patients treated for glaucoma or OHT may benefit from such analysis and future trials for new intraocular pressure-lowering eyedrops should thus evaluate tear osmolarity.”
Dr. Labbé recently presented his data at the Congrès Société Française d’Ophtalmologie:
http://www.sfo2011.fr/donnees/programme/detail-intervention.php?cid=53
Therefore, while many patients chronically exposed to preservatives may not feel like they have been doing damage to their ocular surface, it is now known that there is a way to quantify these iatrogenic effects – by measuring tear osmolarity.
