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We reviewed 121 consecutive patients with biopsy-proven sarcoidosis who visited the sarcoidosis clinic of the University Hospital in Amsterdam, to determine the risk factors for the development of ocular manifestations. Of 121 patients 52 (43%) were black. Ocular disease developed in 50 (41%) patients and was more common in female and in black patients. uveitis was the most frequent manifestation of ocular sarcoidosis (29 out of 50 or 58%). There were no differences in the extra-ocular manifestations of the sarcoidosis between patients with and without ocular disease or between uveitis and non-uveitis patients. This study covered a mixed racial population and shows that different types of uveitis are seen in white and black patients. Anterior uveitis was more frequent in black patients (P less than .001), whereas posterior uveitis was more common in white patients (P less than .01). Chronic posterior uveitis with complications occurred most frequently in white female patients with late onset of the systemic disease. Uveitis was an early feature of sarcoidosis (25 out of 29 or 86%); moreover in 9 out of 29 (31%) cases, uveitis preceded the non-ocular detectable signs of sarcoidosis by more than one year. This emphasizes the importance of periodic re-evaluation of uveitis patients for sarcoidosis.

Concentrations of the metabolites glucose, lactate, pyruvate, and urea were determined in human tear fluid. Collection of the tears in glass capillaries, without mechanical irritation, permitted the estimation of naturally occurring levels of these metabolites. Glucose concentrations were very low, also in diabetics with high blood glucose levels. Lactate was present at higher levels and pyruvate and urea in about the same concentrations as normally for blood. Collection of the tears with filter paper strips as absorbent material caused slight epithelial damage and consequently a loss of the barrier function of the epithelium. In filter paper eluates glucose concentrations were found to be much higher, especially in diabetics with high blood glucose levels. Lactate and pyruvate concentrations were not influenced, whereas the urea concentrations decreased. The value of clinical tear glucose tests is discussed.

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Using high performance liquid chromatography (HPLC) the tear protein profiles were measured in controls, patients with Sjögren's disease, questionable dry eye (idiopathic dry eye), idiopathic chronic conjunctivitis and the corneal melting syndrome. Qualitative comparison of the protein profiles of patients with Sjögren's disease, corneal melting and IgA deficiency shows a marked difference in the heights of various peaks as compared to the profiles of the control group. The total protein content of tears in controls and in patients with idiopathic chronic conjunctivitis is age dependent and appears to increase until the age of 40 and to decrease afterwards. The peaks containing IgA, lactoferrin and lysozyme were measured in various eye diseases. In idiopathic chronic conjunctivitis and in the corneal melting syndrome no differences were seen in comparison with controls. In patients with idiopathic dry eye and Sjögren's disease a marked decrease in the three proteins was seen. The study presented here indicates that the HPLC analysis of tears is a promising technique which may increase our knowledge of this ocular fluid.

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The excretory duct of the lacrimal gland of rabbits and guinea pigs was cannulated in situ for collection of pure lacrimal gland fluid, not contaminated by secretions from the Harderian gland or contributions of desquamating cells of the conjunctival and corneal epithelium. Tears as well as lacrimal gland fluid of both species showed a species-specific and molecular weight-dependent pattern after sodium dodecylsulphate-polyacrylamide (SDS-PAA) gradient slab gel electrophoresis. The most striking difference in both species was a protein corresponding to serum albumin present in tears and almost lacking in lacrimal gland fluid. Likewise, a variety of enzymes, total protein and PGE2 were measured in tears and lacrimal gland fluid. For rabbit tears the lacrimal gland is the primary tissue source of lysozyme (LZM), beta-hexosaminidase (beta-hex), angiotensin-converting enzyme (ACE), plasminogen activator (PA) and total protein, while lactate dehydrogenase (LDH) and the greater part of prostaglandin E2 (PGE2) are present in rabbit tears mainly as products from other ocular tissue sources. In guinea pig tears peroxidase (POD), ACE, PA and less PGE2 are exceted by the lacrimal gland, amylase (AMY), LDH and a substantial amount of PGE2 are added to the guinea pig tears by other ocular tissue sources. Beta-hex and total protein are released from the lacrimal gland and from other ocular tissue sources as well.