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Maninder S. Bhogal, Bruce D. Allan; Effect Of Air Fill Pressure And Graft Thickness On Interface Fluid Dispersion In An Oct Model Of Descemets Stripping Automated Endothelial Keratoplasty. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6024.
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To examine the effect of graft thickness and anterior chamber pressure fill on interface fluid dispersion in a model of DSAEK using anterior segment optical coherence tomography
16 pairs of human corneas with consent for research were used. One cornea in each pair underwent standard microkeratome dissection using a mechanical mircokeratome. A descemetorhexis was performed on the second cornea in the pairing. The 'host' cornea was mounted in an artificial anterior chamber and 'donor' floated into position by an air bubble completely filling the anterior chamber. 8 corneal pairs had a complete fill at 18mmHg and 8 pairs at 60mmHg. Serial OCT images were taken every 2 minutes for 14 minutes in total. Interface fluid area and maximal separation were measured in the horizontal meridian. A Pearson correlation was conducted between graft thickness and interface fluid. Repeated measures anova was used to compare the effects of time and pressure on interface fluid dispersion.
There was a strong correlation between graft thickness and both initial and final interface fluid area (p=0.0002) and maximal separation (p=0.003). There was a significant reduction in interface fluid area over time (p< 0.0001). Anterior chamber filling pressure did not have an effect on rate of fluid dispersion or final fluid dispersion (p= 0.43)
Interface fluid prevents graft apposition and adhesion. Current strategies using a high pressure anterior chamber gas fill in eyes without venting incisions do not offer an advantage in terms of fluid dispersion. Leaving a gasfill for an extended period of time will encourage dispersion of interface fluid. Thinner grafts conform better to the posterior cornea with less initial and final fluid trapping.Graft dislocation remains the most common complication of DSAEK. Dislocation is a definite risk factor for primary failure. Enhanced understanding of graft attachment and fluid dispersion will allow for safer and more successful eyes, many of which are vulnerable to high pressure states.
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