The diagnosis of the aqueous deficient dry eye, keratoconjunctivitis sicca, remains a major clinical problem. Available diagnostic tests are either erratic and inconsistent e.g. Schirmer test or measure phenomena other than tear production i.e. epithelial dessication (Rose Bengal), enzyme content of tears, Lysozyme or Lactoferrin) or tear osmolarity. Tear flow as measured by fluorescein dilution is generally considered to be the best index of aqueous tear production. Surprisingly, no extensive clinical stueies employing this modality in normals and clinically symptomatic abnormals have been published. Moreover, reports to date on other diagnostic tests have not been correlated with this reliable measure of aqueous tear production. This study will measure aqueous tear production by fluorescein dilution in normal and clinically symptomatic abnormal human subjects, to determine possible statistically significant correlations with commonly used diagnostic tests, e.g. the Schirmer test, tear osmolarity, Rose Bengal staining and tear lysozyme levels. The development of a truly extended wear contact lens awaits a lens design consistent with significant tear exchange beneath the lens. The effects of five parameters of lens design on tear exchange will be studied using high molecular weight fluorescein isothiocyanate dextran solutions. These solutions do not penetrate hydrophilic gels of high ater content or the corneal epithelium. The effects of the same five parameter of lens design on the corneal spithelium will be studied. Wide field specular microscopy of the human corneal epithelium reveals patterns of exfoliation which differ in contact lens wearers. The applications of these two techniques i.e. fluorophotometry of the tears and in vivo wide field specular microscopy of th epithelium will answer some critical questions in tear production, tear exchange beneath hydrophilic lenses, and contact lens design effects on epithelial integrity.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY004361-06
Application #
3258727
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1986-08-07
Project End
1990-07-31
Budget Start
1988-08-01
Budget End
1989-07-31
Support Year
6
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Georgetown University
Department
Type
Schools of Medicine
DUNS #
049515844
City
Washington
State
DC
Country
United States
Zip Code
20057
Mathers, W D; Lemp, M A (1992) Morphology and movement of corneal surface cells in humans. Curr Eye Res 11:517-23
Mathers, W D; Lemp, M A (1991) Vortex keratopathy of the corneal graft. Cornea 10:93-9
Ichikawa, H; Kozai, A; MacKeen, D L et al. (1989) Corneal swelling responses with extended wear in naive and adapted subjects with menicon RGP contact lenses. CLAO J 15:192-4
Hideji, I; MacKeen, D L; Hamano, H et al. (1989) Swelling and deswelling of rabbit corneas in response to rigid gas permeable, hydrogel and elastomer contact lens wear. CLAO J 15:290-7
Lemp, M A (1989) The surface of the corneal graft: in vivo color specular microscopic study in the human. Trans Am Ophthalmol Soc 87:619-57
Lemp, M A; Mathers, W D; Gold, J B (1989) Surface cell morphology of the anesthetic human cornea: a color specular microscopic study. Acta Ophthalmol Suppl 192:102-7
Mathers, W D; Jester, J V; Lemp, M A (1988) Return of human corneal sensitivity after penetrating keratoplasty. Arch Ophthalmol 106:210-1
Lemp, M A (1987) Structural considerations in refractive surgery. Trans New Orleans Acad Ophthalmol 35:83-7
Lemp, M A (1987) Extended-wear contact lenses: effects on the cornea. Trans New Orleans Acad Ophthalmol 35:137-42
Lemp, M A (1987) Tear film: new concepts and implications for the management of the dry eye. Trans New Orleans Acad Ophthalmol 35:53-64

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