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Stephen C Pflugfelder1, Christophe Baudouin2,3 1Ophthalmology-Ocular Surface Center, Baylor College of Medicine, Houston, TX, USA; 2Department of Ophthalmology, Quinze-Vingts Hospital, Paris, France; 3Vision Institute, Paris, France Abstract: Ocular surface disease (OSD) is common among glaucoma patients. Clinical assessment of OSD can be challenging. This review focuses on some of the limitations relating to both subjective and objective measures of OSD, including dry eye. A survey of the literature was conducted to identify the caveats associated with different methods of assessing OSD. The effect of preservatives on the ocular surface, with respect to glaucoma patients in particular, was also reviewed. Objective methods for assessing ocular surface health and disease include the Schirmer test, tear break-up time, fluorescein turnover, corneal and conjunctival staining, tear osmolarity, and vital dyes. These measures all have limitations in terms of their ability to grade the severity of OSD. Previous studies using the OSD Index showed a mild-to-moderate correlation to dry eye disease severity. Other scoring systems for dry eye have shown a relationship to patient symptom scores or quality of life. Due to the challenges clinicians face concerning both subjective and objective ocular surface health assessments, discerning clinical improvement in ocular surface disease can be a challenge. Further research is needed in order to optimize existing clinical methods and/or identify alternative techniques for assessing OSD in the glaucoma population. Keywords: dry eye, glaucoma, ocular surface disease, ocular surface disease index, preservatives, tear break-up time

Malgré une conjoncture globalement médiocre, du fait notamment de la crise asiatique et d'un hiver clément dans l'hémisphère nord, l'année 1997 a confirmé les signes d'amélioration de l'activité du raffinage observés en 1996. Mais la situation de ce secteur n'est pas encore satisfaisante : faible rentabilité des capitaux employés, préoccupations quant aux financements des investissements nécessaires à la protection de l'environnement. Pour 1998, la chute des cours des pétroles bruts, qui a évidemment pour corollaire une baisse des prix des produits, a été finalement plutôt favorable aux marges. Deux éléments modèrent ce relatif optimisme : d'une part le maintien d'une très grande volatilité, d'autre part l'accentuation de la crise économique et financière observée au cours de l'été, qui s'est traduite par une forte chute des marges dans toutes les zones géographiques et plus particulièrement en Asie. Début 1999, les marges de raffinage sont restées faibles et ont conduit à une baisse du taux d'utilisation des capacités de traitement. Despite a business environment that was globally mediocre due primarily to the Asian crisis and to a mild winter in the northern hemisphere, the signs of improvement noted in the refining activity in 1996 were borne out in 1997. But the situation is not yet satisfactory in this sector: the low return on invested capital and the financing of environmental protection expenditure are giving cause for concern. In 1998, the drop in crude oil prices and the concomitant fall in petroleum product prices was ultimately rather favorable to margins. Two elements tended to put a damper on this relative optimism. First of all, margins continue to be extremely volatile and, secondly, the worsening of the economic and financial crisis observed during the summer made for a sharp decline in margins in all geographic regions, especially Asia. Since the beginning of 1999, refining margins are weak and utilization rates of refining capacities have decreased.

Depuis quelques années le secteur du raffinage est soumis à rude épreuve. La consommation de produits pétroliers augmente peu en Europe, leurs spécifications se durcissent. En raison notamment des progrès permanents dans l'utilisation des unités, les surcapacités de traitement demeurent. . . Tous ces facteurs réunis font que les marges du raffinage à travers le monde restent faibles et insuffisantes pour financer correctement les investissements nouveaux. Refining margins throughout the world have remained low in 1996. In Europe, in spite of an improvement, particularly during the last few weeks, they are still not high enough to finance new investments. Although the demand for petroleum products is increasing, experts are still sceptical about any rapid recovery due to prevailing overcapacity and to continuing capacity growth. After a historical review of margins and an analysis of margins by regions, we analyse refining overcapacities in Europe and the unbalances between production and demand. Then we discuss the current situation concerning barriers to the rationalisation, agreements between oil companies, and the consequences on the future of refining capacities and margins.