Nasolacrimal obstruction.
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Dacryocystorhinostomy↗
Biomedical subjects
Eric B Papas
Publications and source records attributed to Eric B Papas.
Videoreflective dacryomeniscometry in normal adults and in patients with functional or primary acquired nasolacrimal duct obstruction.
PURPOSE: Videoreflective dacryomeniscometry (VRD) for evaluation of marginal tear film has not been performed in patients with watery eye or in a controlled study. We used VRD to evaluate the height of the central marginal lower lid tear film in normal adults and compared it with two watery-eye groups and a postoperative dacryocystorhinostomy (DCR) group. DESIGN: Case-controlled interventional case series. METHODS: We evaluated with VRD 20 subjects with normal lacrimal drainage function, 21 patients with primary acquired nasolacrimal duct obstruction (PANDO), 28 patients with functional nasolacrimal duct obstruction (FNLDO), and a postoperative group of 14 patients derived from the previous two pathologic groups. Comparison between the four groups was performed to determine statistically significant differences between tear film height. RESULTS: PANDO and FNLDO groups were shown to have significantly greater median tear meniscus heights ([TMH] PANDO: 620 microm, interquartile range [IQR] 453 microm; FNLDO: 731 microm, IQR 529 microm) than normal subjects (296 microm, IQR 214 microm; P < .001) and postoperative PANDO patients (265 microm, IQR 159 microm). There was no significant difference in TMH between PANDO and FNLDO groups preoperatively (P = .275). There was a reduction in median TMH postoperatively of 355 microm (P = .008) in PANDO and 360 microm (P = .068) in FNLDO. CONCLUSIONS: PANDO and FNLDO patients have similar preoperative TMH. In both these groups, TMH is significantly greater than in normal control subjects. Lacrimal drainage surgery substantially reduces TMH as measured using VRD in PANDO.
Aged↗
The limbal vasculature.
The cornea is an avascular structure whose closest point of approach to the systemic blood stream is provided by the limbal vessels. Activity within these structures provides the clinician with a sensitive indicator of contact lens performance and associated problems. In this paper, the anatomy and physiology of the limbal vessels is reviewed with particular attention to the control of capillary perfusion. Mechanisms whereby soft contact lenses can interact with this network of vessels are considered.
Journal Article↗
Clinical appearance and microscopic analysis of mucin balls associated with contact lens wear.
PURPOSE: The structure of mucin balls collected from silicone hydrogel contact lens wearers was examined to determine their nature. METHODS: Tears containing mucin balls were collected using a capillary tube. These were processed for light microscopic histochemistry, scanning electron microscopy, and electron microscopic elemental analysis. Mucin balls were also observed in vivo using confocal microscopy. RESULTS: Histology showed that the mucin balls were PAS positive, indicating that glycoproteins form a major component. Lipids and bacteria were not detected. Scanning electron microscopy did not show the surface to be smooth but revealed a variation in density across the surface. Elemental analysis was inconclusive. CONCLUSIONS: Mucin balls are likely to be made from collapsed mucin and are unlikely to have been formed as a result of pearling around a silicon, lipid, or bacterial kernel.
Contact Lenses↗
The role of hypoxia in the limbal vascular response to soft contact lens wear.
PURPOSE: Increases in limbal vascular blood flow frequently occur as an accompaniment to conventional soft contact lens wear. This study attempted to discover whether these changes can be induced by the direct influence of oxygen alone in the absence of contact lenses. METHODS: Nine people were subjected to monocular anoxia by bathing one randomly chosen eye with 100% nitrogen using gas-tight goggles. Their other eyes served as controls and were exposed to normal air throughout the study. Vascular changes were quantified by image capture and subsequent analysis, with the change in the proportion of the image corresponding to blood vessels (per area) being used as the measure of hyperemia. RESULTS: Nitrogen-exposed eyes showed significantly greater hyperemia (mean perarea change +/- 95% confidence interval, 0.023 +/- 0.016 compared with control eyes, -0.013 +/- 0.013; P=0.004, paired t test). CONCLUSION: Reduced oxygen concentration at the ocular surface induces more blood flow in limbal vessels. This result provides further evidence that similar changes occurring during soft contact lens wear are caused by lens-induced hypoxia.
Blood Flow Velocity↗