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Kristina Spaniol, Jan Hendrik Schwinde, Marianne Hoffmann, Marianne Borrelli, Stefan Schrader, Gerd Geerling; The influence of ocular surface parameters on the visual outcome of Descemet-membrane endothelial keratoplasty. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1202.
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© 2017 Association for Research in Vision and Ophthalmology.
It is yet unclear how ocular surface impairment influences the outcome after Descemet-membrane endothelial keratoplasty (DMEK). Aim of this study was to evaluate the correlation between visual recovery after DMEK and ocular surface disease.
Ninety-three eyes of 79 Patients (26 male, 53 female) were investigated preoperatively, 6 weeks, 6, and 12 months after DMEK (surgery between 06/2012 and 01/2015) for best corrected visual acuity (BCVA in logMar), corneal pachymetry (Pentacam, Oculus, Germany), corneal sensitivity (Cochet-Bonnet aesthesiometer), corneal surface staining with 2% Fluorescein (Oxford Grading Score, OGS: 0=no corneal staining, 12=maximum staining), break up time (BUT), lid parallel conjunctival folds (LIPCOF), and subjective symptoms (Ocular Surface Disease Index, OSDI). Surgery time was recorded with a stopwatch. Statistical analysis was performed with SPSS 22.0 (IBM statistics).
Twelve months postoperatively (postop), BCVA improved from 0.7±0.4 to 0.16±0.1 (p<0.001) and pachymetry decreased from 727±170 to 534±86µm (p=0.014). Corneal sensitivity increased significantly at 6 weeks from 2.5±3 to 5.0±1 and remained stable at the follow up while OGS decreased non-significantly from 3.7±2 to 2.2±2 after 6 weeks. BUT, LIPCOF, and OSDI did not change significantly. Patients with high corneal sensitivity showed better BCVA values, up to 6 months postop (p=0.001; r=-0.53). A higher preoperative OGS correlated significantly with a longer surgery-duration (p<0.002; r=0.78) and a higher early postop OGS with a worse BCVA 6 weeks (p=0.003; r=0.49) while this correlation was not evident at the follow up visits.
This study shows that DMEK leads to a significant improvement of visual acuity and does not impair dry eye parameters, which is consistent with the fact that the corneal nerve plexus is not damaged through surgery. However, corneal surface parameters should be optimized prior to DMEK as an irregular corneal surface may prolong the surgery due to reduced corneal clarity. Superficial corneal irregularities diagnosed by corneal fluorescein staining can cause a lesser BCVA-increase. In such cases, lubricant eye drops should be prescribed postop to improve the visual outcome. Patients with high corneal sensitivity show best early postop BCVA-results, which may be due to intact reflex tearing leading to improved surface parameters.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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