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B. L. Tannen, K. L. Fry, P. S. Hersh; Topographic and Keratometric Changes With Single and Double Intacs for Keratoconus. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5001.
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To investigate topographic and keratometric changes relativeto the placement of Single and Double Intacs in keratoconuspatients at approximately one (PO1) and three (PO2) months.
Topography (Eyesys) and keratometry was reviewed in 24 eyesof 19 patients with keratoconus who had Intacs placed usingthe Intralase laser. Either one (Single) or two (Double) Intacswere placed with the incision along the steep axis. Changesto corneal power centrally and at 3mm and 5mm optical zones(oz) relative to the Intacs placement were analyzed.
Eight eyes had Single and sixteen had Double Intacs placed.Mean age was 31 (Single) and 33 yrs (Double). Single sizes from300 to 450 and Double combinations from 300/300 to 450/350 micronswere placed. Mean follow up for PO1 was 46 (Single) and 42 days(Double). Mean follow up for PO2 was 82 (Single) and 120 days(Double).Changes to UCVA and BCVA are shown in Table 1a. BothUCVA and BCVA improved at PO1 and remained stable at PO2. Keratometricchanges are shown in Table 1b. More flattening occurred alongthe steep than the flat axis with Single (p=0.08). Similar amountsof flattening occurred at each axis with Double.Relative topographicchanges are shown in Table 2. More flattening occurred at the5 than the 3mm oz for both Single and Double. Single causedmore flattening in the inferior than the superior meridiansadjacent to its placement (p<0.05). Double caused more flatteningin the meridians adjacent to the superiorly placed Intac (p=0.07).
Topographic and keratometric changes suggest that differenteffects occur in different regions of the cornea relative toSingle and Double Intacs that may be useful in refining a surgicalnomogram.
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