Author: El Hage S
Institute: Eye Care Associates Houston, USA

Abstract:

Optimizing the outcome of a surgical or non surgical Keratorefractive procedures, requires the knowledge of corneal topography, the shape factor, eccentricity and Q value. Also, the measurement of the wavefront measurement using Zernike polynomial or Fourier analysis, would explain some of the patient complains after an Orthokeratology procedure. Using the EH-300 Optivision corneal topography, we were able to design empirically from the data collected over the cornea (up to 8300 points) a CKR contact lens. The nomogram allows us to "Optimize" the fit and minimize the high order aberration such as coma and spherical aberrations.

Author: Key JE
Institute: Baylor College of Medicine Houston, Texas, USA

Abstract:

Aim: To investigate and quantify differences among contact lens multi-purpose solutions (MPS) as regards silicone hydrogel (SiH) lens wetting, corneal stress and patient comfort.
Patients and methods: Laboratory videography was used to measure and compare wetting angles on SiH lenses preconditioned with various MPS. In addition, studies were performed on adapted contact lens wearers to quantitate corneal stress (staining), subjective rating of comfort and extent of lens coating.
Results:
There are demonstrable differences in wettability, staining and comfort among MPS. The copolymer, Tetronic 1304, demonstrated improved wettability and less corneal staining.
Conclusion: Careful choice of MPS can affect patient comfort and success with SiH contact lenses and promote safer lens wear.

Author: Meshel LG
Institute: USA

Abstract:

Untwinkle, untwinkle little star….now I can tell where you are. Wavefront analysis of the human visual system has allowed us to uncover and correct some 20% to 50% of previously unrecognized errors in the human optical system. These errors are caused by higher order optical aberrations not detected or corrected by traditional manifest refraction which has been performed using spherical and cylindrical lenses for the past 200 years. This traditional refractive method only corrected optical defocus (myopia and hyperopia) and astigmatism.
This presentation will discuss the history, physics, and clinical applications of wavefront optics, and how its understanding has not only improved outcomes of LASIK therapeutics, but has also allowed for production of truly customized “finger print” contact lenses and spectacles which theoretically can realize the full visual potential of the human eye towards achieving “super vision” (20/8 - 3 lines better than the currently considered normal 20/20).

Author: Stock E. Lee Cornea Consultant, S.C.
Institute: Milwaukee, WI, U.S.A.

Abstract:

There is evidence that stem cells for the cornea reside in the limbus. Stem cells may be deficient in aniridia, Stevens-Johnson syndrome and alkali burns. Recent evidence has accumulated that certain patients may develop stem cell deficiency related to contact lens wear.
Stem cells are a population of cells capable of ‘unlimited’ self-renewal that upon division gives rise to progeny (transient amplifying or TA cells) that have limited renewal capability. Stem cells divide relatively infrequently (slow-cycling) in mature nontraumatic tissues, have a high proliferative potential and can be induced to divide more frequently following wounding or in vitro culture conditions. They are relatively small cells, which are structurally and biochemically primitive with less cellular granularity, AND tend to be heavily pigmented in sun-exposed areas.
The clinical picture of stem cell deficiency related to contact lens wear includes inflammation of the limbus with relatively normal conjunctiva. Corneal pannus is present and is most pronounced superiorly.

Author: Chartrand JP
Institute: Contact Lens Clinic McGilll University Montreal, Quebec, Canada

Abstract:

Many refractive surgery patients are contact lens wearers that desire a permanent answer to their vision or contact lens problems.
Those patients have particular expectations and ocular surface altered by the contact lens. A thorough subjective questioning and an objective examination eliminating any contact lens related pathologies are important to obtain the best surgical results.
A special surgical preparation is sometimes necessary as well as an adequate follow-up.