en تخصصي Special پژوهشي Research Article <span style="font-size:12pt"><span style="line-height:16.0pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:9.0pt">Background & Aims</span></i></b><b><span style="font-size:9.0pt">:</span></b> <span style="font-size:9.0pt">Corneal transplantation is considered the most transplanted solid tissue in humans. The purpose of the present investigation was to recognize the main indications and risk factors for allograft rejection.</span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:16.0pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:9.0pt">Materials & Methods</span></i></b><b><span style="font-size:9.0pt">:</span></b><span style="font-size:9.0pt"> The medical files of all subjects who underwent penetrating keratoplasty at a major referral center in Northwest Iran (Urmia Imam Hospital) were retrospectively reviewed, regardless of the indication for transplantation, over a 13-year period, from 20 March 2002 to 19 March 2015. &nbsp;</span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:16.0pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:9.0pt">Results</span></i></b><b><span style="font-size:9.0pt">:</span></b> <a name="_Hlk171978910"><span style="font-size:9.0pt">In total,<b> </b>327 cases of corneal transplantation were examined (mean age: 53.48 &plusmn; 22.44 years). </span></a><span style="font-size:9.0pt">Of these, 170 patients (52%) were male. Out of 327 individuals, 42 cases (12.8%) experienced graft rejection. Nearly three-quarters of rejected transplants (N = 31, 73.8%) occurred in patients &ge; 40 years (<i>p</i> = 0.381). No significant association was detected between graft rejection and gender (<i>p</i> = 0.136). <a name="_Hlk171979878">The most frequent indications for corneal transplantation in cases with rejection were </a>leukoma (N = 13, 31.0%), trauma (N = 12, 28.6%), and pseudophakic bullous keratopathy (PBK) (N = 9, 21.4%). The most prevalent causes of graft rejection included delayed follow-up (N = 17, 40.4%), recurrence of corneal dystrophies (N = 9, 21.4%), and graft failure (N = 9, 21.4%). Only 3 out of 17 patients (17.6%) with delayed follow-up achieved graft restoration.</span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:16.0pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:9.0pt">Conclusion</span></i></b><b><span style="font-size:9.0pt">: </span></b><span style="font-size:9.0pt">This study suggests a link between delayed follow-up and graft rejection. Prompt intervention improves the chances of regaining graft clarity, and patients must be well informed about the importance of follow-up visits.</span></span></span></span> Bullous Keratopathy, Corneal transplantation, Graft rejection, Trauma 298 305 http://hsm.umsu.ac.ir/browse.php?a_code=A-10-268-1&slc_lang=en&sid=1 Naser Samadi Aidenloo samadi.n@umsu.ac.ir 10031947532846003086 10031947532846003086 No Department of Ophthalmology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran Qader Motarjemizadeh qadermotarjemizadeh@gmail.com 10031947532846003087 10031947532846003087 Yes Department of Ophthalmology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran (Corresponding Author) Ayyub Shamsi ayyub.shamsi@gmail.com 10031947532846003088 10031947532846003088 No Department of Ophthalmology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran