Influence of Pars Plana Vitrectomy on Ocular Surface using Non-Invasive Keratograph 5M

Abstract Background: The noninvasive Keratography has been used in evaluating surgery-induced ocular surface changes, while few were known about the influence of pars plana vitrectomy (PPV) on ocular surface. This study aimed to evaluate the influence of PPV on ocular surface using Keratograph 5M. Methods: 30 patients (30 eyes) undergoing primary PPV were recruited in the study. Ocular Surface Disease Index (OSDI) questionnaire was performed. Ocular surface parameters, including tear meniscus height (TMH), noninvasive tear break up time (NITBUT) and bulbar redness score were obtained preoperatively, at 1 week, 2 weeks, 4 weeks, 8 weeks and 12 weeks postoperatively by Keratograph 5M. Correlations between all the clinical parameters were analyzed further. Results: The percentages of both photophobia and gritty within 4 weeks after PPV were significantly higher than preoperation, while they decreased to the preoperative levels at both 8 weeks and 12 weeks postoperatively. The percentage of sore eyes within 2 weeks postoperatively was significantly higher than preoperation, but there were no significant differences between the percentages of preoperation and 4 weeks, 8 weeks and 12 weeks postoperatively. OSDI score increased significantly within 8 weeks postoperatively, but it returned to the preoperative level at 12 weeks. TMH was increased significantly at the first week after PPV, and recoverd to preoperative level at 2 weeks postoperatively. Both NITBUT-first and NITBUT-average shortened significantly within 8 weeks postoperatively, but they gradually improved to the preoperative levels at 12 weeks. Bulbar redness score was significantly higher than preoperative level within 4 weeks postoperatively, but it returned to the preoperative level at 8 weeks. NITBUT-first and NITBUT-average had a significant positive correlation at each visit. OSDI score had a significant positive correlation with bulbar redness, and TMH had a significant positive correlation with NITBUT-average at both 1 week and 2 weeks postoperatively. Conclusions: Keratograph 5M can provide a reliable noninvasive method to assess the influence of PPV on ocular surface. PPV may cause various changes in both symptoms and signs of ocular surface damages at an early stage, while all these changes will return to preoperative levels gradually at 12 weeks postoperatively.