23,083 research outputs found
An Unusual Melanocytic Nevus of Conjunctiva : Balloon Cell Nevus
Melanocytic nevi are one of the most common benign tumors of the conjunctiva. The balloon cell nevus is a rare and unusual variant of nevus of melanocytic origin, in which more than 50% of the tumor is composed of large polygonal cells with small nucleus and a clear to vacuolated cytoplasm. We describe a case of balloon cell nevus in a 6-year-old child who presented with pigmented lesion of the right eye since birth. The melanocytic nature of these cells was confirmed by immunohistochemical study. Excision of the tumor results in cure. This report describes a rare balloon cell nevus of conjunctiva which to the best of our knowledge is not documented in Indian literature
A solute gradient in the tear meniscus I. A hypothesis to explain Marx's line
Marx's line is a line of mucosal staining behind the mucocutaneous junction. It can be demonstrated throughout life in all normal lids by staining with lissamine green and related dyes. Of all the body orifices, only the mucosae of the eye and mouth are directly exposed to the atmosphere. In this paper, we suggest that for the eye, this exposure leads to the formation of Marx's line. The tear meniscus thins progressively toward its apex, where it is pinned at the mucocutaneous junction of the lid. It also thins toward the black line, which segregates the meniscus from the tear film after the blink. We predict that, because of the geometry of the tear meniscus, evaporation generates a solute gradient across the meniscus profile in the anteroposterior plane, which peaks at the meniscus apices at the end of the interblink. One outcome would be to amplify the level of tear molarity at these sites so that they reach hyperosmolar proportions. Preliminary mathematical modeling suggests that dilution of this effect by advection and diffusion of solute away from the meniscus apex at the mucocutaneous junction will be restricted by spatial constraints, the presence of tear and surface mucins at this site, and limited fluid flow. We conclude that evaporative water loss from the tear meniscus may result in a physiological zone of hyperosmolar and related stresses to the occlusal conjunctiva, directly behind the mucocutaneous junction. We hypothesize that this stimulates a high epithelial cell turnover at this site, incomplete epithelial maturation, and a failure to express key molecules such as MUC 16 and galectin-3, which, with the tight junctions between surface epithelial cells, are necessary to seal the ocular surface and prevent penetration of dyes and other molecules into the epithelium. This is proposed as the basis for Marx's line. In Part II of this paper (also published in this issue of The Ocular Surface), we address additional pathophysiological consequences of this mechanism, affecting lid margins
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Pro-Secretory Activity and Pharmacology in Rabbits of an Aminophenyl-1,3,5-Triazine CFTR Activator for Dry Eye Disorders.
PurposePharmacological activation of ocular surface cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels is a potential pro-secretory approach to treat dry eye disorders. We previously reported the discovery of aminophenyl-1,3,5-triazines, one of which, N-methyl-N-phenyl-6-(2,2,3,3-tetrafluoropropoxy)-1,3,5-triazine-2,4-diamine (herein called CFTRact-K267), fully activated human wildtype CFTR with EC50 ∼ 30 nM and increased tear volume for 8 hours in mice. Here, functional and pharmacological studies of CFTRact-K267 were done in adult New Zealand white rabbits.MethodsCFTR chloride conductance was measured in vivo by ocular surface potential differences and in ex vivo conjunctiva by short-circuit current. Tear volume was measured by the Schirmer tear test II and CFTRact-K267 pharmacokinetics and tissue distribution by liquid chromatography/mass spectrometry. Toxicity profile was studied for 28 days with twice-daily topical administration.ResultsElectrophysiological measurements in vivo and in ex vivo conjunctiva demonstrated CFTR activation by CFTRact-K267. A single topical dose of 3 nmol CFTRact-K267 increased tear production by >5 mm for 9 hours by the Schirmer tear test, with predicted therapeutic concentrations maintained in tear fluid. No tachyphylaxis was seen following 28-day twice-daily administration, and changes were not observed in corneal surface integrity or thickness, intraocular pressure, or ocular histology. At day 28, CFTRact-K267 was concentrated in the cornea and conjunctiva and was not detectable in blood or peripheral organs.ConclusionsThese studies support the development of CFTRact-K267 as a pro-secretory therapy for dry eye disorders
A comparison of two conjunctival rotation autograft techniques in primary pterygium surgery.
PURPOSE: To compare the effects of 90° and 180° conjunctival rotational autograft (CRA) techniques used in primary pterygium surgery.
METHODS: Forty-five patients were included in this retrospective study. Visual acuity (VA), corneal topography, and auto-refractometer measurements, as well as detailed biomicroscopic examinations, were performed preoperatively and postoperatively. During surgery, the pterygium tissue was excised then rotated 90° in Group 1 and180° in Group 2, after which it was sutured to the bare sclera. Pterygium recurrence was defined as corneal invasion ≥1 mm.
RESULTS: Group 1 consisted of 21 patients with a mean age of 45.1 ± 11.8 years, while Group 2 comprised 24 patients with a mean age of 47.9 ± 13.8 years. The pterygia in Group 1 were graded as more advanced than those in Group 2. A similar number of recurrences were observed in Group 1 (14.3%) and in Group 2 (16.7%). There was no statistically significant difference in terms of the preoperative and postoperative VA and astigmatism values between the two groups. There was a statistically significant improvement in the postoperative VA and astigmatism values in Group 1 and in the postoperative astigmatism values in Group 2. Although postoperative redness was more common in Group 1, no statistically significant difference was found between the groups.
CONCLUSION: BothCRA techniques can be successful in patients for whom it is desirable to avoid a conjunctival autograft and for patients without high cosmetic expectations
A solute gradient in the tear meniscus II. implications for lid margin disease, including meibomian gland dysfunction
We have hypothesized previously that evaporation from the tears generates a solute gradient across the tear meniscus, which delivers hyperosmolar stress to the mucocutaneous junction (MCJ) of the lid margin. This is proposed as the basis for Marx's line, a line of staining with topically applied dyes that lies directly behind the MCJ. In this article, we consider the implications of this hypothesis for progressive damage to the lid margin as an age-related phenomenon, its amplification in dry eye states, and its possible role in the etiology of meibomian gland dysfunction (MGD). It is suggested that a hyperosmolar or related stimulus, acting behind the MCJ over a lifetime, promotes the anterior migration of the MCJ, which is a feature of the aging lid margin. This mechanism would be amplified in dry eye states, not only by reason of increased tear molarity at the meniscus apex but also by raising the concentration of inflammatory peptides at this site. This could explain the increased width and irregularity of Marx's line in dry eye. While the presence of stem cells at the lid margin may equip this region to respond to such stress, their depletion could be the basis of irreversible lid margin damage. It is further proposed, given the proximity of the MCJ to the meibomian gland orifices, that the solute gradient mechanism could play a role in the initiation of MGD by delivering hyperosmolar and inflammatory stresses to the terminal ducts and orifices of the glands. By the same token, the presence of a zone of increased epithelial permeability in this region may provide a back door route for the delivery of drugs in the treatment of MGD
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