Authors (including presenting author) :
Chow Y(1), To W(1), Ng SK(1), Leung KP(1), Wong C(1), Wong WY(2)
Affiliation :
(1)Hospital Authority Eye Bank, (2)Hong Kong West Cluster
Introduction :
In Descemet’s stripping automated endothelial keratoplasty (DSAEK), an automated microkeratome is used to produce a thin donor graft for endothelial keratoplasty (EK). In Hong Kong, Hospital Authority Eye Bank (Eye Bank) started to perform automated posterior lamellar graft preparation (precut) since 2008.
Objectives :
To review and compare the trend of precut in our Eye Bank with US in the past decade.
Methodology :
The statistics of precut between 2009 and 2018 were analyzed which included posterior thickness (PT) of precut corneas, the change in endothelial cell density (ECD), the day from recovery to precut, number of perforation during precut and other complications. Also, we compared with those in US released by Eye Bank Association of America.
Result & Outcome :
560 precut corneas were prepared by Eye Bank in the past decade. The numbers doubled from 31 in 2009 to 63 in 2015. The latest figure was 72 in 2018. A significant difference in precut rate between 2009-2015 and 2016-2018 (p=0.0017) was demonstrated. A similar raising trend was observed in US (r=0.8871). A 33.1% decrease in the mean PT from 162.7±31.8μm in 2009 to 108.8±18.6μm in 2018 was noted. Mean ECD before and after precut were 2900.8±273.4 and 2816.9±284.1 per square millimeter. There was 2.9% of ECD loss after precut which was lower than our previous study (6.3% in 2014). The day from recovery to precut was 5.3±1.6. There were 9 perforations (1.8%) during precut, one primary graft failure and one bacteria growth which might be attributable to EK. Eye Bank plays a critical role in the recovery, evaluation and processing of cornea for transplant. This latter role has expanded with growing demands of DSAEK. Therefore, additional manpower and microkeratomes have been instituted. Standard operation procedures were established and enhanced, and anterior segment optical coherence tomography was introduced in 2012. Most importantly, precut is a highly skilled process and Eye Bank has equipped Eye Technicians with the expertise through overseas training, certified examinations and annual competency evaluations. With more experience, there is a decrease in PT of precut corneas which can lead to a better clinical outcome as DSAEK with thinner grafts are linked to improved visual acuity. The decreasing ECD loss, high precut successful rate and paucity of complications are strong indication of the technical performance.
