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Bruno Lay, Christine W Sindt, David Slater; Normative Scleral Lens Landing Data. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3081.
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© ARVO (1962-2015); The Authors (2016-present)
Standardized fitting sets are currently the most common way to fit scleral lenses. Recent publications have shown vast differences in the elevation of scleral topography in different meridians of the eye. Most scleral lenses are designed with rotational symmetry, with either spherical or toric peripheral curves, with possibly minor focal changes to account for localized irregularity. No lenses account for rotational elevation differences, even though it is known the nasal sclera has a higher elevation than the temporal sclera. We propose a normative database can be determined using elevation specific data, to design a standardized scleral lens fitting set with rotationally asymmetric differences in scleral lens landing zone elevation. Elevation specific fitting sets should allow for faster and more physiologically aligned scleral lens determination.
Using impression technology to capture true 3-D ocular surface topography, 3+ points are chosen to define the limbal circle and limbal plane on the impression displayed in the user interface. Starting 1.5 mm beyond the limbus, the distance from the limbal plane to the scleral surface is measured. A series of concentric scleral rings, 100 microns apart with 90 points of interest per ring, serve as the data locations for the limbal plane to scleral surface measurements. Concentric rings are measured up to 4mm beyond the limbus. All elevation data are exported to a generic file that can be later used for statistical analysis.Data points may be used to find trends in the scleral elevation data.
Elevation data based on a limbal plane efficiently finds elevation changes from the limbal plane, in addition to toricity changes and can be incorporated into scleral lens landing design. This elevation data may be analyzed for various populations.
Normative scleral lens landing data can be efficiently collected and utilized in scleral lens designs. This allows standardized fitting sets to be developed to better align the peripheral eye.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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