Scleral-Contact Lenses

Fringe TopographyWhat did we learn about ocular contour?A new technology formeasuring the cornea andscleral surface shape hasbeen developed in theDepartment of Optometryat the Beuth Hochschulefor Applied Sciences atBerlin, Germany. GlobalContact No.2/2009(52)Precision measurement of ocular sag every 60 microns of chord over 15.5 mm0 0.06 0.12 0.18 0.24 0.3 0.36 0.42 0.48 0.54 0.6 0.66 0.72 0.78 0.84 0.9 0.960 0.002302 0.006083 0.010255 0.014707 0.021918 0.02698 0.032601 0.036583 0.043705 0.051786 0.060478 0.06819 0.075681 0.084563 0.092945 0.1038160 0.001329 0.002908 0.004338 0.005507 0.007736 0.010835 0.014525 0.018684 0.023823 0.029262 0.034311 0.039131 0.04467 0.051099 0.058258 0.0662870 0.001232 0.002564 0.004226 0.006098 0.00895 0.011612 0.014734 0.020186 0.026258 0.03126 0.037081 0.042443 0.046195 0.051727 0.060049 0.0686410 0.001105 0.003301 0.004596 0.005292 0.007657 0.010202 0.011308 0.012343 0.013469 0.015734 0.019949 0.025655 0.03095 0.035495 0.039451 0.0452460 0.002963 0.007667 0.01047 0.012323 0.012156 0.01398 0.014403 0.016006 0.01879 0.022703 0.026226 0.024539 0.030923 0.032526 0.039639 0.0468130 0.000496 0.002262 0.004108 0.007234 0.01083 0.013237 0.015643 0.019469 0.023235 0.027091 0.031167 0.036673 0.044169 0.050975 0.056251 0.0615280 -0.001451 0.000278 0.004427 0.007396 0.008625 0.009194 0.010723 0.014922 0.020522 0.025091 0.03163 0.040489 0.046878 0.050857 0.055586 0.063715Contour Data for Mean EyeContour Data to Six Standard DeviationsAverage Sag OD (mm)4.543.532.521.510.50-8.5 -8 -7.5 -7 -6.5 -6 -5.5 -5 -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5-0.5Average Sag OS(mm)4.543.532.521.510.5OD n = 93 Nasal TemporalSemi-chord (mm) 6.48 -5.22 5.22 q -6.48 qAverage Sag (mm) 3.00 1.95 41.8 1.88 2.81 38.7Standard Deviation (mm) 0.259 0.128 4.067 0.080 0.162 3.3160-8.5 -8 -7.5 -7 -6.5 -6 -5.5 -5 -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5-0.5The Enigma of Scleral ContourConvex Landing Zone GeometryRed = Mean eye profileGreen = Lens with concavescleral zoneBlack = Lens with uncurvedscleral zoneBlue = Lens with convextoward scleraEven a scleral zone having no curvature will bury into the scleraA convex curve toward the eye is required to create edge lift(Patent pending)Red = Mean ScleraGreen = Standard concave to eyeBlack = Un-curved targeted to touch at 13.0 mmBlue = Convex to eye targeted to touch at 13.0 mm2