Corneal Research Articles

Progress of diagnosis and treatment of familial hypercholesterolemia

Familial hypercholesterolemia is a rarely genetic disorder of lipid metabolism.The Clinical manifestations are high serum cholesterol, yellow tumor, corneal arch, atherosclerosis, or early coronary heart disease.Recently, we have been made great progress on Familial hypercholesterolemia in domestic and foreign researches, but our understanding is still insufficient.We aim to overview genetics and current perspectives on diagnosis and treatment.Prompt diagnosis, intervention of individualized drug treatment control and follow-up management contribute to increase awareness, and add decades of life for people with Familial hypercholesterolemia. Key words: Familial hypercholesterolemia; Low density lipoprotein; Low-density lipoprotein cholesterol; Genetics; Diagnosis; Treatment

Protective efficacy of bandage lens on corneal flap of patients with retinal detachment after LASIK surgery

Objective To evaluate the protective efficacy of bandage contact lens on corneal flap for retinal detachment patients with LASIK history. Methods A prospective, self-controlled clinical study. Nine eyes of 9 patients with retinal detachment who had history of LASIK were enrolled. All cases underwent vitreoretinal surgery with non-contact wide-angle lens. Corneal bandage lenses were used to completely cover the surface of the corneal flap during surgery. The visual acuity, IOP, corneal fluorescein sodium staining, tear function, corneal thickness and corneal endothelial cell density at 1 d, 1 week and 1 month postoperatively were recorded. Results No corneal flap displacement or loss occurred in 9 cases. Before surgery corneal fluorescein staining showed scattered cornea around the next spot color in 7 cases. The score of corneal fluorescein staining was (2.00±0.87) 1 d after surgery, it was higher than that before surgery (t=-5.547, P=0.001). The score returned to preoperative level at 1 week after surgery. BUT was agreement with results of corneal fluorescein sodium staining. The corneal thickness at 1 week after surgery was (531.78±24.17)μm, it was thicker than that before surgery(t=-4.918, P=0.001). The difference of corneal thickness was not statistically significant between before and 1 month after surgery. The difference of Schirmer Ⅰtest and corneal endothelial cell density were not statistically significant between before and after surgery. Conclusion Application of corneal bandage lens for retinal detachment patients with history of LASIK can protect corneal flap, recovery early of tear film stability, effectively protect the corneal function. Key words: Retinal detachment, after surgery, laser in situ keratomileusis(LASIK); Vitreoretinal surgery; Bandage contact lens; Corneal flap

Observation on the efficacy of retinoic acid for alkali corneal burn in rats

Objective To observe the efficacy of retinoic acid (RA) for the treatment of rats with corneal alkali burn. Methods The corneal alkali burn model of 36 Sprague-Dawley rats was established, all cases were randomly divided into RA group and control group, with 18 cases in each. RA group received RA eye drops and the control group received lysozyme of RA eye drops. The corneal morphology changes, conjunctival goblet cell count and corneal neovascularization area were measured. The number of inflammatory cells and expression of inflammatory factor in the corneal line of rat were observed by HE staining and immunohistochemical staining. Results The corneal neovascular area and inflammatory cell count after corneal alkali burn in RA group were lower than those of the control group. The conjunctival goblet cells count were higher than those of the control group at 4 and 7 days after corneal alkali burn, the difference was not significant at 14 days after corneal alkali burn. The expression of IL-1α, NF-κB and VEGF in the RA group were lower than those in the control group at 4 and 7 days after corneal alkali burn. At 14 days after corneal alkali burn, the VEGF expression in the RA group was lower than that of the control group, but the difference in the expression of IL-1α and NF-κB were not significant between the two group (IL-1α: 1.84±0.15 and 2.01±0.19, t=-2.26, P=0.347; NF-κB: 1.83±0.35 and 2.00±0.33, t=-2.59, P=0.695). Conclusion RA can control corneal inflammatory reaction and neovascularization by inhibiting the expression of IL-1α, NF-κB and VEGF. RA is effective for the treatment of alkali corneal burn. Key words: Retinoic acid; Burn, alkali, corneal; Neovascularization

Bandage contact lenses for the treatment of acute ocular chemical injuries

Objective To observe the application efficacy of bandage contact lens(BCL) for the treatment of acute ocular chemical injuries. Methods Prospective case-control study. Seventy-seven eyes of 50 patients with ocular chemical injuries were randomly divided into 2 groups: observation group, 39 eyes of 25 patients and control group, 38 eyes of 25 patients. All patients were treated with routine anti-inflammatory and reparative treatment after emergency treatment. The observation group received normal treatment combined with BCL.The changes in corneal epithelial, symptom scores, corneal epithelial healing time and complications after treatment were observed and recorded. Results All BCLs were successfully fit patients of observation group, no any related complication occurred. The scores of symptoms and corneal fluorescence staining in observation group were significantly lower than those in the control group at 1, 3 and 7 days after treatment(all P<0.05). The difference of scores of the two groups were not significant between before and 14 days after treatment (P=0.311). The average time of corneal epithelial healing in observation group was (2.670±0.982) days and (5.870±1.711 )days in the control group, the difference was statistically significant between the two groups(t=-10.769, P<0.05). Conclusion Application of BCL for the treatment of acute ocular chemical injuries is effective for shorting the time of re-epithelialization and reducing postoperative pain. Key words: Bandage, contact lens, cornea; Injuries, chemical, ocular

Analysis on the efficacy of biological amniotic membrane transplantation for complicated ocular surface diseases

Objective To evaluate the clinical efficacy of biological amniotic membrane transplantation in complicated ocular surface disease and ocular surface reconstruction. Methods The data of 74 eyes of 74 patients with complicated ocular surface disease from Jan. 2011 to Dec. 2016 were analyzed retrospectively. They underwent biological amniotic membrane transplantation. Results The most common primary diseases was recurrent pterygium in 25 eyes (33.78%), followed by corneal ulcer in 20 eyes (27.03%), chemical injury in 15 eyes (20.27%), symblepharon in 10 eyes (13.51%), persistent epithelial defects (PED) in 2 eyes (2.70%), eyelid basal cell carcinoma in 1 eye (1.35%) and Stevens-Johnson syndrome (SJS) in 1 eye (1.35%). After 6 - 24 months follow-up, there were 12 eyes (16.22%) reoperated, including pterygium recurrence in 3 eyes (3/25, 12.00%), corneal ulcer in 2 eyes (2/20, 10.00%), chemical injury in 4 eyes (4/15, 26.67%), symblepharon in 2 eyes (2/10, 20.00%), SJS 1 in eye (1/1, 100.00%). No infection, graft rejection or allergic reaction after surgery occurred. Conclusion Amniotic membrane transplantation is an effective method for the treatment of complicated ocular surface diseases. Key words: Transplantation, biological amniotic membrane; Diseases, ocular surface; Pterygium; Ulcer, corneal; Injury, chemical

Comparison of the efficacy between phacoemulsification and small incision extracapsular cataract extraction for the treatment of cataract

Objective To compare the efficacy between phacoemulsification and small incision extracapsular cataract extraction for the treatment of senile cataract. Methods The data of 198 eyes of 198 patients with senile cataract from May 2015 to May 2017 were analyzed retrospectively. All cases were divided randomly into 2 groups. Small incision group, 120 patients, underwent small incision extracapsular cataract extraction, and phacoemulsification group, 78 patients, received phacoemulsification. The efficacy, complications and corneal endothelial cell density between two groups were compared. Results The visual acuity of two groups at 3 d, 1 and 3 months after operation were improved (P 0.05). The astigmatism degree of both groups at 3 d and 1 month after operation were increased (P 0.05). Before operation, the difference in endothelial cell densities and hexagonal cell ratio between two groups were not significant (P>0.05). After operation, the endothelial cell densities and hexagonal cell ratio of both groups were decreased (P<0.05), and the small incision group were lower than phacoemulsification group (P<0.05). Conclusion Both phacoemulsification and small incision extracapsular cataract extraction can get good curative effect in the treatment of senile cataract, and phacoemulsification may have an advantage on protecting the corneal endothelial cells. Key words: Phacoemulsification; Cataract extraction, small incision; Cataract, senior

Characteristics of posterior corneal astigmatism and aberration in cataract patients with high myopia

Objective This study was to investigate the characteristics of posterior corneal astigmatism (PCA) and aberration in cataract patients with high myopia. Methods A retrospective study was designed.Two hundred and eighty-two eligible eyes of 190 cataract patients were enrolled in Eye and ENT Hospital of Fudan University from September to December, 2014.The eyes were classified into two groups according to axial length (AL): high myopia group with 139 eyes (AL≥26 mm) and control group with 143 eyes (AL was 20 to 25 mm). The mean keratometric mid-radius of curvature (Km), corneal central thickness (CCT), astigmatism and aberrations were measured by the rotating Scheimpflug System (Pentacam), and the AL were measured by the partial coherence interferometry (IOL Master). This study followed the Helsinki declaration, and was approved by the Ethic Committee of Eye and ENT Hospital, Fudan University.Informed consent was signed from each patient. Results In high myopia group, the mean PCA was 0.3 D (range 0~0.9 D) and 92.8% eyes had PCA values <0.5 D. The steep corneal meridian was aligned vertically (60°~120°) in 87.1% eyes for the posterior corneal surface.There was no significant difference in PCA between the high myopia group and the control group (P=0.797). Significant positive linear correlations was found between PCA and anterior corneal astigmatism (ACA), PCA and anterior corneal root mean square (RMS), PCA and anterior lower-order RMS, PCA and posterior corneal RMS, PCA and posterior high-order RMS, PCA and posterior lower-order RMS (r=0.235, P=0.005; r=0.217, P=0.010; r=0.229, P=0.007; r=0.395, P=0.000; r=0.243, P=0.004; r=0.384, P=0.000). Compared with total corneal astigmatism (TCA), anterior corneal measurements overestimated with-the-rule astigmatism (WTR) by a mean of (0.27±0.18)D in 65.67% eyes, underestimated against-the-rule astigmatism (ATR) by (0.27±0.18)D in 88.10% eyes and underestimated oblique astigmatism (Obl) by (0.22±0.10)D in 63.33% eyes.Compared with total corneal aberrations, anterior corneal aberrations measurements overestimated by (0.275±0.176)μm in 87.05% eyes, and the anterior corneal astigmatism types had no effect on the result. Conclusions In high myopia group, 92.8% eyes had PCA values <0.5 D and the main astigmatism type in posterior corneal surface was ATR.The posterior corneal astigmatism and aberration were needed to consider in choosing intraocular lens (IOL) before cataract surgery. Key words: High myopia; Secondary cataract; Posterior corneal surface; Astigmatism; Aberration

Correlation analysis between corneal biomechanical properties and high-order aberration in myopia

Objective To investigate the correlations between corneal biomechanical properties and corneal high-order aberrations (HOAs) in myopic eyes. Methods In this retrospective study, 263 right eyes with myopia or myopic astigmatism were enrolled from January to October 2015 in Tianjin Eye Hospital.The values of first applanation time (A1T), first applanation length (A1L), first applanation velocity (A1V), second applanation time (A2T), second applanation length (A2L), second applanation velocity (A2V), highest concavity time (HCT), highest concavity deformation amplitude (HCDA), highest concavity peak distance (HCPD), highest concavity radius (HCR) and non-contact intraocular pressure (IOPnct) were measured using the corneal visualization Scheimpflug technology (Corvis ST). The central corneal thickness (CCT) and wavefront aberrations of the anterior, posterior surface, and the total cornea were measured with Pentacam.Pearson correlation and stepwise multivariate linear regression analysis were applied to analyze the correlations between biomechanical properties and corneal HOAs.This study follows the Helsinki declaration.The experiment was approved by the Ethic Committee of Tianjin Eye Hospital.Informed consent was signed from each patient. Results There was a correlation between biomechanical properties and corneal HOAs.Negative correlations were found between A1L and the spherical aberration, HOAs RMS of anterior surface, total RMS and HOAs RMS of the posterior surface and HOAs RMS of the total cornea (P<0.05). HCRs were negatively correlated with total RMS of the total cornea and the anterior surface (P<0.05). The A2V was correlated with various aberrations.Multiple stepwise linear regression model analysis showed that, the correlation between the aberrations of anterior surface and biomechanical parameters, and the correlations between the total corneal aberration and biomechanical parameters were weak, the correlations between the aberrations of posterior surface and biomechanical parameters were strong. Conclusions There is a correlation between the biomechanical properties and corneal HOAs.The changes of the corneal biomechanical properties are mainly associated with the posterior corneal aberrations, which may contribute to the early diagnosis of subclinical keratoconus or dilated corneal disease. Key words: Corneal biomechanical properties; Aberration; Visual quality

Application of optical coherence tomography angiography in ocular anterior segment diseases

Optical coherence tomography angiography (OCTA) is a rapid, noninvasive new blood flow imaging technique that was first applied to retinal retinopathy and acquired retinal vascular imaging in only a few seconds.Compared with the traditional optical coherence tomography(OCT), OCTA analyze has the advantages of higher resolution, faster scanning speed, quantitative blood flow, etc.OCTA not only can more accurately and qualitatively analyze ocular vascular morphology, but also can measure blood vessels and blood flow perfusion noninvasively and quantitatively.With the application of anti angiogenesis drugs in the anterior segment, it is important to evaluate the neovascularization of the cornea and iris in order to guide the clinical medication and evaluate the therapeutic effect.This article reviewed the application of OCTA in ocular anterior segment diseases, such as cornea and iris diseases, etc. Key words: Optical coherence tomography angiography; Cornea; Iris; Application

Effects of operative design during small incision lenticule extraction on surgical outcomes

As a relatively new procedure, small incision lenticule extraction (SMILE) is still in its initial stage.Despite the fact that it has shown safety, efficacy, predictability, and stability, the clinical outcomes were diversiform among individuals.How to improve visual quality by designing individualized parameters is one of the researching focuses in corneal refractive surgery.This article reviewed the operative design, such as pluse energy, scanning patterns, cap, incision, optical zone and its influences on surgical results. Key words: Small incision lenticule extraction; Operative design; Effects

Observation on the effect of applying mitomycin C in transepithelial photorefractive keratectomy

Objective To observe the efficacy of applying mitomycin C(MMC)in transepithelial photorefractive keratectomy(TPRK )surgery. Methods A retrospective nonrandomized controlled study. The data of 122 eyes of 61 cases received TPRK surgery were collected and analyzed.All cases were divided into two groups.Group A, 60 eyes of 30 patients, 0.02% MMC sponge was put on to the cornea ablation area during operation for 20-40 s; group B, 62 eyes of 31 cases received surgery without MMC. The follow-up time was 6 months.The incidence of haze formation, cornea epithelium healing and visual acuity of the two groups were observed. Results The eye irritation symptoms of group B was lighter than that of group A, the difference was statistically significant between the two groups (t=7.582, P=0.000). At 3 and 10 days postoperatively corneal epithelium repair were faster, the difference was statistically significant between the two groups(P=0.002, 0.007). The visual acuity at 3, 10 days, 1 and 3 months after surgery was same with that before surgery.The difference was not statistically significant(χ2=0.439, P=0.508; χ2=2.367, P=0.124; χ2=0.370, P=0.543; χ2=0.919, P=0.338). The difference in incidence of haze was not statistically significant between the two groups(χ2=0.726, P=0.190). Conclusion During TPRK surgery without MMC can reduce postoperative eye irritation, and repair corneal epithelium relatively fast, without influence on visual recovery and the incidence of haze. Key words: Keratectomy, transepithelial, photorefractive; Mitomycin C, intraoperative application; Haze, corneal; Visual acuity

Observation on the efficacy of Tacrolimus eye drops for preventing rejection after high-risk corneal transplantation

Objective To observe the efficacy of Tacrolimus eye drops for preventing rejection after treatment of high-risk penetrating keratoplasty in patients with poor response to Cyclosporin A eye drops. Methods The data of 10 eyes of 9 patients with high-risk penetrating keratoplasty from Apr. 2008 to Jun. 2015 were analyzed retrospectively. Cyclosporine A eye drops were applied after the first penetrating keratoplasty. Five eyes were treated with Tacrolimus eye drops after secondary penetrating keratoplasty, and the other 5 eyes were treated with Cyclosporine A eye drops. Results Ten eyes were followed up for (41.70±8.53) months after corneal transplantating, rejection happened in 9 eyes(90.00%) . All eyes underwent penetrating keratoplasty due to grafts opacification. Five eyes were treated with Tacrolimus eye drops and followed up for (16.00±2.68) months. The rejection occurred in 2 eyes(40.00%). The other 5 eyes were treated with Cyclosporin A and followed up for (36.20±7.95) months. The rejection rate was 100.00%. After treatment of Tacrolimus eye drops, the grafts of 5 eyes were transparent and followed up for (13.40±3.17) months. In the follow-up period, rejection occurred in 1 eye(20.00%). Conclusion Tacrolimus eye drops is applied for preventing rejection in high-risk keratoplasty patients with poor response to Cyclosporin A eye drops, most patients can get better anti-immune rejection effects. Key words: Keratoplasty, penetrating; Eye drops, Tacrolimus; Rejection, immune; Efficacy

Relationship between age and intraocular lens diopter prediction error

Objective To investigate the relationship between intraocular lens (IOL) diopter prediction error (PE) and ages of patient with cataract . Methods A prospective nonrandom cohort study. The data of 525 eyes of 525 patients with cataract were collected and they were divided into 4 groups according to age. Age ≤ 59 years group were in 75 eyes of 75 cases, and 150 eyes of 150 patients in each other 3 groups (60-69, 70-79 and 80-89 years). All cases received phacoemulsification and implantation of a single-piece acrylic IOL. The IOL diopter was calculated by the optimized SRK/T formula.Objective refraction was measured with an auto-refractomer 3 months postoperatively.The mean PE and absolute PE were compared among 4 groups. Results The difference of mean preoperative refractive prediction error by the SRK/T formula was statistically significant among 4 groups (P=0.418). Mean PE was 0.24 diopters (D) in≤59 years group, 0.17 D in 60-69 years group, 0.11 D in 70-79 years group, and 0.05 D in 80-89 years group. The difference in median absolute PE was not statistically significant among groups (P=0.619). Mean PE was positively correlated with age (P=0.000). Multiple regression analysis revealed that age, preoperative axial length, average corneal curvature, and anterior chamber depth were independent predictors of the age-related difference in PE. Conclusion PE is less of 0.06 D per decade as age increased, suggesting that age of patient should be considered when selecting IOL diopter. Key words: Cataract; Phacoemulsification; Lens, intraocular; Prediction error, dioptric

Central Corneal Thickness and Endothelial Damage After Cataract Surgery

Central Corneal Thickness and Endothelial Damage After Cataract Surgery

Advances in corneal wound healing and stroma remodeling

Stroma is the major part of cornea.The factors maintain corneal stroma transparency include the ultrastructural anatomy and physiology of the cornea and its cellular and extracellular components.During corneal development, neural crest cells and keratoblasts differentiate into keratocytes, which synthesize high levels of collagen and proteoglycans.The production and assembly of collagen fibers need a series of intracellular and extracellular components.The assembled collagen fibers deposite in ECM, assemble into high-order structures to synthesize small fiber bundles, and then form a larger structure in a particular tissue.Corneal wound healing is completed in highly coordinate by various cells and cytokines in time and space.The keratocytes phenotype changes and the remodeling of corneal stroma ECM are two important factors in this process.Corneal refractive surgery are carried out in the worldwide, although most corneal refractive surgery are successful, But the stromal opacity formed during the remodeling of corneal stroma is the most important cause of visual impairment and visual quality decline after refractive surgery.Well understanding the course of stroma remodeling after corneal injury, is meaningful for the exploration of decreasing corneal opacity formation.In this paper, the corneal stroma structure and its synthesis and assembly, the pathophysiological process of stroma remodeling in corneal wound healing and after corneal refractive surgery were reviewed. Key words: Corneal stroma; Corneal wound healing; Stroma remodeling; Refractive surgery

Research progress of the robot-assisted ophthalmology surgery

Surgical robots have the advantages of high precision, high flexibility, high repeatability, and merging with minimally invasive surgery to solve the shortcomings of traditional minimally invasive surgery, and gradually into all fields of medicine.Foreign scholars have extensive research on medical surgical robots.Currently, Da Vinci surgical robots are the most widely used and most mature surgical robot system.Although our scholars started later, they also successfully developed a corneal transplant robot, MiaoShou-A robot, robotic vitreoretinal microsurgery system and so on.At present, Robot-assisted surgery are widely used in various medical fields, which has also been used in ophthalmology.Robot-assisted surgery can reduce the physiological tremor of the surgeon; improve surgical stability and accuracy; shorten the learning curve and so on.At present, Da Vinci surgical robots can perfectly complete the ocular surface surgery such as suturing of the corneal laceration, corneal whole-layer transplantation, amniotic membrane transplantation and pterygium excision.The corneal transplantation microsurgery robot developed by our country can also complete corneal looping incision and suturing of the corneal.As Da Vinci surgical robots have some limitations and can't be well used in complex intraocular surgery such as vitreoretinal surgery.Handheld robot system, steady-hand robot system, master-slave robot system and various kinds of robots based on these systems are used in intraocular surgery.The pars plana vitrectomy(PPV), retinal foreign body Removal, retinal vascular sheath sclerosis, retinal vascular cannulation had successfully performed in harvested porcine eyes and endolaser for retinal photocoagulation was done in Irish rabbit.It offers the possibility for future intraocular surgery with robot-assisted.At the same time, wider application research of robotic surgery and improvement of a robotic system should be continued. Key words: Robot; Ophthalmology; Research progress

Clinical Evaluation of Surgical Procedures for Corneal Ulcer in Dogs

The present study was conducted on 12 dogs, irrespective of age sex and breed, having corneal ulcer to evaluate the response of surgical procedures on corneal ulcer. The animals were randomly divided into two groups, in group I temporary tarsorrhaphy and in group II third eyelid flap surgery was performed along with pre and post-operative systemic and local medication. Preoperative ophthalmoscopic examination was performed before starting the treatment, i.e. day 0, to check the general health status of the animals, followed by day 15, 30, 45 and 60 post-operative examination to record the healing of corneal ulcer. In group I lesser complications were observed as compared to group II and 66.66% and 50.00% dogs recovered without scar formation on 60th post-operative day in group I and II, respectively. Thus temporary tarsorrhaphy was observed superior then the third eyelid flap surgery as well as combination of moxifloxacin and flurbiprofen was found satisfactory for the healing of corneal ulcer.

Incidence of eye affections in dogs.

A total of 8760 cases of dogs registered at TVCC of college of veterinary science and A.H. Jabalpur during the period of 9 months (August, 2015 to April, 2016) were screened. Out of these 3872 (44.20%) cases were referred to Department of Veterinary Surgery and Radiology, of which 122 (1.39%) dogs were suffering with various eye affections. Majority of the animals were affected with cataract (38.52%), followed by corneal ulcer (13.11%). The incidence of rest of the eye affections was less. Majority of animals were non-descript (38.62%), between 6 to 10 years (47.54%) of age. Sex wise incidence was higher in male (70.49%) dogs.

The variation of corneal curvature of diabetic patients after small-incision extracapsular cataract extraction

Objective To analyse the variation of corneal curvature of diabetic patients after small incision non-phacoemulsification extracapsular cataract extraction. Methods The data of 83 eyes of 71 patients with cataract and diabetic from Apr.2009 to Apr.2012 were collected and all cases were divided into 3 groups: normal control group, diabetic groupⅠ(blood glucose<9.0 mmol/L) and diabetic groupⅡ(blood glucose≥9.0 mmol/ L). The follow-up time was 12 months. Results Horizontal corneal curvature (HCC) of the three groups after surgery were higher than that of before surgery, the difference was statistically significant (P<0.001). Vertical corneal curvature (VCC) after surgery were lower than that before surgery (P<0.001). The difference value of HCC in control group and diabetic groupⅠwere decreased 3 days-12 months after surgery (P<0.05). The difference value of HCC in diabetic groupⅡwas decreased from 3 days to 6 months after surgery (P<0.05), the difference value was not changed from 6 to 12 months after surgery (t=0.292, P=0.774). The difference value of VCC in control group and diabetic group Ⅱwere decreased 3 days-12 months after surgery (P<0.05). The difference value of VCC in diabetic groupⅠwas decreased 3 days-6 months after surgery (P<0.05), the difference value remained stable at 6-12 months after surgery (t=1.578, P=0.129). Conclusion HCC of the three groups are elevated and VCC are decreased, the degree of change is proportional to the level of blood glucose, the healing process of corneal acomplishes almost from half year to 1 year. Key words: Extracapsular cataract extraction, small-incision; Patient, diabetic; Corneal curvature

Risk factor analysis of persistent corneal epithelial defects after vitrectomy in patients with proliferative diabetic retinopathy

Objective To analyze the risk factors for persistent corneal epithelial defects (PCED) after pars plana vitrectomy (PPV) in patients with proliferative diabetic retinopathy (PDR). Methods A total of 201 PDR patients (201 eyes) who received PPV were enrolled in this retrospective study. There were 86 males (86 eyes) and 115 females (115 eyes). The patients aged from 30 to 81 years, with the mean age of (57.94±9.65) years. Among them, 159 patients were ≥50 years of age, and 42 patients were 1000 points were performed in 123 eyes. Sixty-one eyes involved intravitreal silicone oil tamponade, 18 eyes involved intravitreal tamponade with C3F8, and 122 eyes were not involved with intraocular tamponade. Postoperative persistent intraocular hypertension was defined as an intraocular pressure (IOP) ≥21 mmHg (1 mmHg=0.133 kPa) after PPV with necessary treatment using IOP-lowering medications for ≥2 weeks. The diagnostic criteria for corneal epithelial defects were taken from the Expert Consensus on Clinical Diagnosis and Treatment of Corneal Epithelial Defect in China (2016). The corneal epithelial defect was diagnosed as PCED if it was treated with common methods such as a lacrimal substitute or corneal contact lens, but showed no improvement and no signs of healing for ≥2 weeks. The incidence of PCED after eye surgery was recorded and its related risk factors were analyzed. A multivariate logistic regression was used to analyze the risk factors for PCED, which were expressed as a odds ratio (OR) and a 95% confidence interval (CI). Results Of 201 eyes, 16 eyes (7.96%) presented with PCED after surgery and 185 eyes (92.04%) with no PCED. There was no significant difference in the age, sex, and eyes between the patients with or without PCED (χ2=6.548, 0.927, 0.044; P=0.011, 0.336, 0.833). A multivariate logistic regression showed that intraoperative epithelial debridement (OR=13.239, 95%CI 2.999−58.442, P=0.001), intraoperative treatment in combination with cataract surgery (OR=7.448, 95%CI 1.975−28.091, P=0.003), intravitreal tamponade with C3F8 (OR=11.344, 95%CI 2.169−59.324, P=0.004), and postoperative persistent intraocular hypertension (OR=10.462, 95%CI 2.464−44.414, P=0.001) were risk factors for PCED after PPV. Conclusion Intraoperative epithelial debridement, intraoperative treatment in combination with cataract surgery, intravitreal tamponade with C3F8, and postoperative persistent intraocular hypertension are risk factors for PCED in patients with PDR after PPV. Key words: Epithelium, corneal/injuries; Vitreoretinal surgery; Diabetic retinopathy