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K. L. Fry, P. S. Hersh; The Influence of Corneal Biomechanics on Conductive Keratoplasty Outcomes. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5361.
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© ARVO (1962-2015); The Authors (2016-present)
To analyze the influence of corneal biomechanical properties on CK outcomes.
A prospective study was carried out on 26 patients that underwent CK treatment for +1.0 to +2.0D of presbyopia in the non-dominant eye. Ten patients also underwent CK treatment in the dominant eye for hyperopia. Mean preoperative manifest refraction spherical equivalent (MRSE) for distance treated eyes was +0.71D (SD 0.26) and +0.31D (SD 0.46) in near eyes. Pre- and postoperative data at 1, 3 and 6 months following surgery were assessed including: UCVA, BSCVA, MRSE, predictability (achieved minus attempted correction) and stability. The Ocular Response Analyzer (Reichert Inc.) was used to gather biomechanical data, including corneal hysteresis (CH) and corneal resistance factor (CRF).
For all eyes (n=36), mean preoperative CH was 10.03 mmHg (SD 1.56) and CRF was 10.11 mmHg (SD 1.58). Following surgery, no significant changes in CH or CRF were observed for all time periods. No significant association was observed between CH and predictability. A weak correlation between CRF and predictability was found. Eyes having higher initial CRF (>10mmHg) showed a greater propensity to be more under-corrected or more hyperopic after surgery compared to eyes with lower (≤ 10mmHg) CRF (p=0.05 at 1 month, p=0.01 at 3 months). No significant correlation was shown for preoperative CH or CRF and regression following CK
Incorporating biomechanical properties of the cornea in planning CK surgery strategies may lead to increased predictability of the surgery. However, the lack of strong correlation to one measurement implies that many factors may be involved in determining final outcome.
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