Donald R. Korb

Correlation of lipid layer thickness measurements with fluorescein tear film break-up time and Schirmer's test

AbstractPurpose This study correlates measurement of lipid layer thickness (LLT) with two frequently used dry eye tests, fluorescein break-up time (FBUT) and Schirmers test with anaesthesia (STA).Methods Subjects (n=44 eyes) with symptoms of dry eye and positive results for dry eye with either FBUT or STA or both were selected. Quantification of LLT was performed by the observation of colour interference patterns in zones of specular reflection using a custom-designed instrument.Results All correlations among pairs of tests were strong and exhibited a significance of P<0.000: STA with FBUT, Pearsons correlation 0.653; STA with LLT, 0.764; FBUT with LLT, 0.751. When LLT was high, ie ≥120u2009nm, which occurred in 14 eyes, STA was also elevated in those eyes and FBUT was high in 13 of the 14 eyes. When LLT was low, ie ≤60, which occurred in 22 eyes, STA was below normal in 14 of the 22 eyes, and FBUT was below normal in 15 of the 22 eyes. These clinical observations paralleled the statistical findings computed from the entire data set.Conclusions The correlations demonstrated in this study support the premise (1) that measurement of LLT is a reliable test for the diagnosis of dry eye, and (2) that aqueous deficiency and lipid deficiency, as they apply to dry eye disorders, are not mutually exclusive.

Histochemical analysis of secretory vesicles in nongoblet conjunctival epithelial cells

Abstract. An Alcian‐blue/Periodic acid Schiff reagent (AB/PAS) pH dependent staining method was used to identify the mucus content of secretory vesicles of nongoblet epithelial cells of the human conjunctiva. Twenty subjects were selected for biopsy of the midcentral upper tarsal conjunctiva: 10 subjects had no contact lens wearing experience, and 10 subjects wore contact lenses. Human respiratory epithelium was used as a control for the staining procedure. Four‐micron paraffin sections of conjunctival and control tissues were stained with Alcian blue at pH 2.5 and 1.0 and counterstained with PAS. Non‐goblet epithelial cell secretory vesicles contained neutral mucin, sialmucin, and sulphomucin. This study provides evidence for a ‘second’ mucus system of the conjunctiva, that this system is in the non‐goblet epithelial cells, and that the mucus of this system has sulphomucins, sialomucins and neutral mucins.

Biomicroscopy of papillae associated with wearing of soft contact lenses.

We studied the topographical, macrostructural, and fluorescein staining characteristics of papillary changes of the upper tarsal conjunctiva associated with the wearing of hydrophilic (soft) contact lenses. Fifty soft contact lens wearers with elevated conjunctival papillae greater than 0.3 mm in diameter were studied. Topographic characteristics recorded were distribution and number of papillae; macrostructural characteristics recorded were diameter and morphology of papillae. The information collected included age of patient, duration of lens wear, average daily time of wearing lens, presence or absence of itching or mucus, refractive status, and atopic history. Papillae were found in most cases in the conjunctival zone adjacent to the tarsal fold and were never found in the zone adjacent to the eyelid margin without also occurring in the intervening zone. The diameter of the papillae ranged from greater than 0.3 mm to 2.0 mm. The number of papillae per eyelid ranged from 4 to over 100. The apices of the papillae were frequently flattened, and these flattened surfaces frequently stained with fluorescein. The vascular supply of individual papillae was observed to radiate from a vessel occupying the central core of each papilla.

Response of the Ocular Surface to Histamine

Eye rubbing results in ocular surface changes, such as irregular epithelial cell morphology, alterations in microprojections, and increased cellular exfoliation. It is unknown whether such changes are related entirely to the mechanical trauma of eye rubbing or manifest secondary to the effects of histamine released from degranulated mast cells associated with eye rubbing. To distinguish between these effects, the present study examines the effects of topical histamine application in the absence of applied mechanical trauma. The bulbar and tarsal conjunctiva of rabbits (n=10) exposed to 25 μl of histamine (25 mg/ml) for 10 minutes were examined using scanning electron microscopy. Contralateral untreated eyes served as controls. Regions studied included the bulbar and tarsal conjunctivae. The bulbar conjunctiva was divided into two regions, the interpalpebral bulbar conjunctiva and that portion unexposed to the environment. In contrast to control eyes, the interpalpebral bulbar conjunctiva of treated eyes had surface cells with irregular morphology and elevated apices. The goblet cell intercellular crypt openings in treated eyes had minimal mucus, while in control conjunctiva most intercellular openings contained mucus. The upper tarsal conjunctiva of treated eyes had an irregular surface and empty intercellular crypt orifices when compared to the smooth tarsal conjunctival surface and mucus-con- taining crypts of control eyes. The lower tarsal conjunctiva had minimal differences in surface cell morphology and did not appear notably altered, in contrast to the upper tarsal conjunctiva. In summary, topical histamine resulted in alteration of the exposed bulbar conjunctiva and upper tarsal conjunctiva, whereas the unexposed bulbar conjunctiva and lower tarsal conjunctiva surfaces exhibited only subtle changes. Perhaps the changes observed in the upper tarsal conjunctiva resulted from the blinking (wiping) action of the upper lid over the chemotic exposed bulbar conjunctiva. The paucity of mucus in the goblet cell orifices after histamine exposure was unexpected.