[Mitomycin C related complications shouldn't be neglected in the pterygium surgery].

Mitomycin C (MMC), as it could reduce tissue adhesions and scar formation, has been widely adopted in pterygium surgery to lower the recurrence rate.Upon a certain therapeutic effect obtained, a variety of ocular complications was combined and always occupies a quite long time after MMC application.once occurred, it was tough to cure. Compared to autologous limbal-conjunctival grafts, MMC has no apparent advantage to reduce reoccurrence of pterygium. Therefore, it is advised to abandon the use of MMC in pterygium surgery.

[Several problems of diagnosis and treatment in fungal keratitis in China].

Fungal keratitis is one of major blindness disease in corneal infection. At present, mistake and missed diagnosis were often happened in Fungal keratitis. Initial doctor was insufficient knowledge of diagnosis. There were not to do etiology examination in corneal fungal infection, and lead to some case getting worse during medicinal treated. Highly ratio patients need controlled infection by corneal transplantation due to severe lack antifungal eye drops, and poor understood the way of antifungal medicine in clinic. Finally, Fungal keratitis is still one of major intractable disease in corneal infection, because some doctor were short of experience to hold surgical opportunity and indication, and corneal donor severe shortage in China.

[Preliminary clinical results of deep anterior lamellar keratoplasty in the treatment deep infectious purulent keratitis].

OBJECTIVE: To evaluate the clinical results of deep anterior lamellar keratoplasty (DALK) assisted by big bubble technique in the treatment of deep infectious purulent keratitis. METHODS: Seventeen patients (17 eyes) with deep infectious purulent keratitis received DALK surgery in Shandong Eye Hospital from January 2011 to March 2012. Case selection:Patients with purulent keratitis, the infection or infiltrate depth was more than four fifth corneal thickness; SURGICAL TECHNIQUE: Use DALK assisted by big bubble technique to cut off the lesions and expose the Descemet's membrane. The prepared donor which stored in D-X medium or in glycerine preoperatively was oversized by 0.25 mm, and after stripping of Descemet's membrane, the donor button was interrupted sutured with 10-0 nylon suture. The perioperative complications, recurrence, graft status and visual recovery were evaluated. RESULTS: The mean follow up time were 9 months.17 patients with average age of (46 ± 13) year old received DALK surgery, including 14 cases of fungal keratitis and 3 cases of bacteria keratitis. Perioperative complications:Two cases suffered micro perforation and were continuing performed DALK surgery after injecting air bubble in the anterior chamber. Three cases suffered double anterior chamber, one was resolved after graft resuture, and the other two were absorbed automatically.One patient suffered fungal recurrence and cured with secondary penetrating keratoplasty. Graft status:All grafts attached closely to the recipients, slit lamp and AS-OCT examinations were difficult to distinguish the interface. All of grafts were transparent. Visual acuity:before the operation best corrected visual acuity (BCVA) in patients with HM/20 cm to 3.7, after the surgery patients' BSCVA improved to 4.5-5.0. The mean astigmatism postoperatively of 16 cases received successful DALK finally was (4.53 ± 2.35) D . CONCLUSIONS: For patients with deep infectious purulent keratitis, big bubble technique assistants DALK surgery is still a safe and effective method.

Single-cell RNA sequencing in cornea research: Insights into limbal stem cells and their niche regulation.

The corneal epithelium is composed of stratified squamous epithelial cells on the outer surface of the eye, which acts as a protective barrier and is critical for clear and stable vision. Its continuous renewal or wound healing depends on the proliferation and differentiation of limbal stem cells (LSCs), a cell population that resides at the limbus in a highly regulated niche. Dysfunction of LSCs or their niche can cause limbal stem cell deficiency, a disease that is manifested by failed epithelial wound healing or even blindness. Nevertheless, compared to stem cells in other tissues, little is known about the LSCs and their niche. With the advent of single-cell RNA sequencing, our understanding of LSC characteristics and their microenvironment has grown considerably. In this review, we summarized the current findings from single-cell studies in the field of cornea research and focused on important advancements driven by this technology, including the heterogeneity of the LSC population, novel LSC markers and regulation of the LSC niche, which will provide a reference for clinical issues such as corneal epithelial wound healing, ocular surface reconstruction and interventions for related diseases.

Should ocular Demodex be checked and treated in refractory keratitis patients without blepharitis?

AIM: To evaluate the correlation between Demodex infestation and keratitis, and to assess demodicosis using a simple approach. METHODS: A modified slit lamp illumination (at 40× magnification) was used to observe Demodex tails in 40 patients with refractory keratitis and 80 healthy controls. Bacterial smear and culture of the conjunctival sac and corneal lesion were performed to identify the pathogen. Tea tree oil ointment (TTOO) was added as a Demodex killing agent for lid scrubs to the treatment when Demodex infestation was confirmed. RESULTS: Demodex tails were found in all patients compared to 42/80 of the controls (P<0.01). Seventeen patients presented blepharitis, while 23 were free of scales and inflammation at the lid margin. The demodicosis was mild, moderate, and severe in 8, 19, and 13 patients, respectively, compared to mild in 42 controls (P<0.01). The keratitis was mild, moderate, and severe in 13, 19, and 8 patients, respectively. The severity of Demodex infestation was not correlated to the severity of keratitis (P=0.126). The growth of Staphylococcus was revealed in nine patients who did not react to antibiotic eye drops prior to the TTOO treatment. Patients' signs and symptoms got resolved after the lid scrub with TTOO. CONCLUSION: Ocular Demodex needs to be checked and treated in refractory keratitis patients with or without blepharitis. A slit-lamp illumination under high magnification favors the judgment of the severity of Demodex infestation.

[Strengthen the study of several issues on diagnosis and treatment of the corneal herpetic endotheliitis].

Herpes simplex keratitis (HSK), including epithelial keratitis, stromal keratitis, and endotheliitis, is one of the major blinding eye diseases in China. Corneal herpetic endotheliitis has a variety of clinical manifestations, which causes much difficulty for diagnosis and treatment. This paper suggests a uniform classification of corneal herpetic endotheliitis, which helps to the set up and wide application of a standard treatment protocol. As a result, the cure rate would be increased significantly, corneal endothelium loss due to misdiagnosis would be reduced, and finally the blindness rate of HSK would be lowered.

[The preliminary study of establishing animal model of chronic allograft dysfunction after penetrating keratoplasty].

OBJECTIVE: To establish a murine model of chronic corneal allograft dysfunction (CCAD) after penetrating keratoplasty (PK). METHODS: Experimental study. PK model in mice: Semiallogeneic CB6F1 mice were obtained from matching of female BALB/c and male C57BL/6 mice. C57BL/6 (allogeneic group), CB6F1 (semiallogeneic group) and BALB/c (syngeneic group) grafts were transplanted orthotopically to BALB/c recipients respectively, and BALB/c mice as a control group. The follow-up time was more than 100 d, and graft survival time and corneal opacity score were monitored, and corneal endothelium were examined by alizarin red and PI/Hoechst stain. CD4(+) and CD8(+) T lymphocytes were examined by immunohistochemistry. Ultrastructure changes of the grafts were examined by electronmicroscopy. Log-rank test were used to compare survival curves. RESULTS: (1) Graft examination:Median graft survival times were 17.0 d, 85.5 d, > 100 d and > 100 d in allogeneic, semiallogeneic, syngeneic and control groups, respectively (F = 344.0, P < 0.01). (2) Immunohistochemistry examination: There were large amount of CD4(+) and CD8(+) T lymphocyte infiltration in allografts in allogeneic group at 3 weeks after PK; Few CD4(+) and CD8(+) T lymphocytes were observed in semiallogeneic group and syngeneic groups at 3 weeks after PK; CD4(+) and CD8(+) T lymphocyte infiltration was not observed in the control group. (3) Endothelium examination: The endothelium can not be counted because the blurred image after the alizarin red combined PI/Hoechst stain and apoptotic and necrotic cells can be seen in allogeneic group; the endothelial cell density decreased and few apoptosis can be detected in semiallogeneic and syngeneic groups; no apoptotic and necrotic endothelial cells were found in the control group. (4) Ultrastructural characteristic changes mainly include fibrosis formation and endothelium atrophy and degeneration in failed grafts in all transplanted groups by electron microscopy examination. Inflammation cells can only be found in the allogeneic group. CONCLUSIONS: Semiallogeneic and syngeneic transplantation groups present the changes similar to CCAD in clinical study, and both can be regarded as the model that permits molecular evaluation of CCAD.

[Clinical application of irrigation in therapeutic keratoplasty for suppurative keratitis with severe hypopyon].

OBJECTIVE: To investigate the safety and clinical efficacy of anterior chamber irrigation combined with corneal transplantation in the treatment of corneal ulcer with severe hypopyon. METHODS: Non-randomized retrospective case series. Twenty patients (20 eyes) suffered from corneal ulcer with severe hypopyon were enrolled in Shandong Eye Hospital from January 2008 to June 2009, and 13 patients with significant corneal endothelial plaque, which hard to determine the lesion edge under microscope. Twenty patients received anterior chamber irrigation combined with penetrating or lamellar keratoplasty treatment; the donors were preserved in the medium-term preservation solution or freeze-dry preservation of glycerine. Intraoperative and postoperative complications, visual acuity, immune rejection were collected as outcome measures. RESULTS: Twenty cases received anterior chamber irrigation combined with corneal transplantation successfully, eleven of which received penetrating keratoplasty (PK) and 9 received lamellar keratoplasty (LK). Ten cases that underwent PK using donors preserved in medium-term solution, and the remaining using donors cryopreserved at -20 degrees C. Intraoperative complications include bleeding iris (11 cases), postoperative complications including iris adhesions (8 cases), transient high intraocular pressure (4 cases), anterior chamber hemorrhage (5 cases), and were cured after drug treatment. One case suffered recurrence of fungal keratitis and received repeat PK. Four cases occurred endothelial immune rejection, 3 cases were controlled and 1 case occurred graft failure after anti-rejection treatment. In the final follow-up in December 2009, 17 grafts were clear and 3 grafts were edema. CONCLUSION: In the treatment of severe corneal ulcer with hypopyon, anterior chamber irrigation combined with penetrating or lamellar keratoplasty is an effective and a safety method.

Multi-level consistent changes of the ECM pathway identified in a typical keratoconus twin's family by multi-omics analysis.

BACKGROUND: Keratoconus (KC) is a common, degenerative disorder of the cornea, and genetic factors play a key role in its development. However, the genetic etiology of KC is still unclear. This study used the family of twins as material, using, for the first time, multi-omics analysis, to systematically display the changes in KC candidate factors in patients at the DNA, RNA, and protein levels. These can evaluate candidate pathogenic factors in depth and lock onto pathogenic targets. RESULTS: The twins in this study presented classic phenotypes, clear diagnoses, complete case data, and clinical samples, which are excellent materials for genetically studying KC. Whole-exome sequencing was conducted on both the twins and their parents. Transcriptome sequencing was conducted on proband's and health individual's primary human corneal fibroblast cells. Quantitative Real-time PCR and western blot were used to validate the differential gene expressions between the proband and controls. By integrating genomics, transcriptome, and protein level data, multiple consecutive events of KC were systematically analyzed to help better understand the molecular mechanism and genetic basis of KC. The results showed that the accumulation of rare, micro-effect risk variants was the pathogenic factor in this Chinese KC family. Consistent changes in extracellular matrices (ECMs) at the DNA and RNA levels suggested that ECM related changes play a key role in KC pathogenesis. The major gene variants (WNT16, CD248, COL6A2, COL4A3 and ADAMTS3) may affect the expression of related collagens or ECM proteins, thus reducing the amount of ECM in corneas and resulting in KC. CONCLUSIONS: This study, the first to explore the genetic etiology of KC via multi-omics analysis under the polygenetic model, has provided new insights into the genetic mechanisms underlying KC and an effective strategy for studying KC pathogenesis in the future.

[Pay attention to a reasonable systemic medication in corneal disease].

Local medication is the main method for the treatment of corneal diseases. Eye drops and eye ointment are the main preparations. But many corneal diseases are related closely with systematic diseases and local medication is insufficient for the treatment of these corneal diseases. Lack of systemic medication can aggravate these corneal diseases. Conversely, if systemic medication is used in all patients with corneal disease, it can lead to an adverse drug reaction. Therefore, it is very important to use systemic medication in corneal disease properly. This article discusses the ignorance and abuse of systemic medication in the treatment of corneal disease.

[Relationship between corneal neovascularization and various relevant biological factors in surrounding cornea stroma of rats].

OBJECTIVE: To study the relationship between corneal neovascularization and various biological factors in corneal stroma of rats. METHODS: It was an experimental study. Corneal neovascularization was induced by alkali burn in 40 rats. Transforming growth factor-beta1 (TGF-beta1), alpha-smooth muscle actin (alpha-SMA) and fibroblast activation protein (FAP) in the stroma surrounding corneal neovascularization were detected by immunohistochemical studies on day 1, 3 and 7 after chemical burn. Platelet-endothelial cell adhesion molecule-1 (CD31) was used to identify the vascular endothelial cells. RT-PCR was used to identify FAP in the cornea 3 and 7 days after chemical burn. Picrosirius staining and polarization microscopy were used to detect changes of collagen types I and III in the cornea. RESULTS: After alkali burn, TGF-beta1 was first expressed in the cornea stroma. Then, some stroma cells expressed both alpha-SMA and FAP. The FAP(+) keratocytes were found surrounding the CD31(+) endothelium of angiogenesis. RT-PCR study showed that FAP mRNA was only present in neovascularized cornea and not in normal cornea. Polarization microscopy revealed that the collagen types I and III were rearranged in neovascularized cornea. CONCLUSIONS: Various biological factors in corneal stroma are changed when the cornea shows neovascularization. FAP(+) keratocytes are present in the stroma, and the appearance of these cells parallels the growth of vascular endothelial cells. Collagen types I and III are rearranged during the process of angiogenesis.

[Virulence of extracellular phospholipase B of Candida albicans in rabbit experimental keratomycosis].

OBJECTIVE: To determine the virulence of extracellular phospholipase B (PLB) of Candida albicans in experimental keratomycosis. METHODS: It was an experimental study. The PLB-deficient mutant strain of Candida albicans and its isogenic parental strain were used in this study. The effects of these two strains on the model of experimental keratomycosis in 48 New Zealand albino rabbits covered with contact lens was compared by observing the dynamic changes clinically and histopathologically. In vitro, these two strains were incubated with the corneal stromal cells separately (37 degrees C, 5% CO2). The influence of these two strains on monolayer keratocytes were detected by scanning electron microscopy (SEM), enzyme linked immunosorbent assay (ELISA), and flow cytometry with Annexin V/propidium iodide. RESULTS: The hyphae of these two strains grew perpendicularly to the corneal stromal lamellae. The difference of the hyphal invasion inoculated for 2 days by these two isogenic strains was statistically significant (P = 0.002), but at other intervals, no significant difference was found. The severity of the inflammation in parental keratomycosis was the same as that in PLB null strain at any time points (P > 0.05). Under SEM, the morphogenesis and the number of adherent germ tubes of these two isogenic strains appeared similarly (P > 0.05), but the number of germ tubes penetrating cell monolayer was significantly different (P = 0.009). Obviously more prostaglandin E2 (PGE2) was detected in the culture supernatants of parental strain group (65,466 +/- 5773) pg/ml than that of the null strain group (18,025 +/- 5232) pg/ml. The percentages of the cells with damaged cellular membrane in the parental group, the PLB null group and the control group, were 3.02%, 2.04% and 0.12%, respectively. The percentages of apoptosis cells in these three groups were 33.17%, 27.56% and 1.46%, respectively. The percentages of living cells were 63.81%, 70.40% and 98.41%, respectively. CONCLUSIONS: PLB shows virulent effects in triggering fungal invasion in cornea immediately following fungal adherence by decomposing membrane phospholipids and leading to cell lysis. However, its virulent effect does not appear to be critical as in the hematogenous model of disseminated candidiasis.

[Reconstruction tissue-engineered corneal epithelium using xenogeneic acellular corneal stroma as scaffold].

OBJECTIVE: To compare two methods for preparing acellular corneal stroma and evaluate the possibility of culturing corneal epithelium on xenogeneic acellular corneal stroma. METHODS: Experimental study, applying completely randomized design method. Dispase followed by Triton-X-100 detergent and sodium chloride SDS detergent followed by trypsinase were applied respectively to treat the rabbit cornea. The characteristics of corneal stroma and acellular status after treatment were examined with slit lamp, optical microscope and transmission electron microscope. The rabbit limbal cells were then cultured on the acellular porcine Bowman's membrane/stroma. Rabbit corneal epithelium lamella reconstructed in vitro and evaluated in morphology, histopathology and immunohisto-chemistry. RESULTS: Acellular corneal stroma prepared by two different methods is quite similar in morphology, being gray and opaque with visible edema and soft texture. Collagen fibers of the stroma were regularly in histopathology and ultrastructure. But the one prepared by the NaCl-SDS-Trypsinase method retained a amounts of cell debris, while there was none in the other did by Dispase-Triton-X-100 method. The limbal cells began to shift out at 24 hours after being inoculated on xenogeneic acellular corneal stroma, then attached on it, formed a confluent monolayer containing normal-appearing in 7 days. The tissue engineering corneal epithelium was cryosectioned and characterized immunohistochemically at 14 days after inoculation. Meanwhile, epithelium associated antigen CK3 in endochylema was stained. CONCLUSIONS: Dispase-Triton-X-100 was proved better in obtaining acellular corneal stroma. It is possible to reconstruction tissue-engineered rabbit's corneal epithelium on acellular porcine corneal Bowman's membrane/stroma.

[Biocompatibility of acellular corneal stroma and transplantation of tissue-engineered corneal epithelium].

OBJECTIVE: To evaluate the biocompatibility of xenogeneic acellular corneal stroma, the feasibility of tissue engineered corneal epithelial transplantation, and verify the long term survival of epithelial allograft. METHODS: It was a experimental study. Porcine corneal stroma was treated by dispase followed by Triton-X-100 detergent. Treated porcine corneal stroma (group A) or fresh corneal stroma (group B) were put into the sac of rabbit cornea. Rabbit cornea without implantation of porcine corneal stroma was used as the control group (group C). Immunological rejection was evaluated in morphology, histopathology and immunohistochemistry in month 1, 3, 6. Female rabbit underwent lamellar keratoplasty (LK) using male tissue engineered corneal epithelium as donors, and immunological rejection after LK was analyzed. The corneas were collected at day 1, 3, 7, 15 and 30 after LK and evaluated by histopathology, immunohistochemistry and sex-determining region of Y-chromosome (SRY)-PCR analysis. RESULTS: All corneas became transparent gradually after the transplantation of treated porcine corneal stroma and were not rejected. The epithelium, stroma, endothelium, Bowman's and Descemet's membrane were preserved in all corneas of group A and B in histological observations, collagen fibers were parallel, a few keratocytes presented in the acellular and fresh corneal stromas. The corneas of group C were normal in histological sections. No significant immune rejection was noted in any of the corneas. The corneas in the study of transplantation of tissue engineered cornea epithelium recovered smoothly in 3 or 4 days, turned transparent in 15 or 20 days after surgery and were not stained by fluorescein. Well-differentiated corneal epithelium were recognized at 15 and 30 days after LK. Many keratocytes infiltrated into the scaffold. SRY-PCR analysis showed that allogenic donor corneal epithelium cells could survive in recipients after a long-term observation. CONCLUSIONS: Acellular porcine corneal stroma shows a satisfying biocompatibility. Tissue engineered corneal epithelium using acellular porcine corneal stroma as carrier could be used as donors for LK with satisfactory results. Donor cells have the potential to survive in recipients after long-term observation.

[CTLA4-FasL protein for the prevention of immune rejection in mouse corneal transplantation].

OBJECTIVE: To investigate the therapeutic effect of double-functioned CTLA4-FasL protein for the prevention of immune rejection in murine corneal allografts. METHODS: It was a experimental study. C57BL/6 mice (n = 45) were as donors and BALB/c mice (n = 90) as recipients. BALB/c mice accepted penetrating keratoplasty were randomly divided into 3 groups including no therapy (A), CsA DDS implanted in anterior chamber (B), 10 microg/mL CTLA4-FasL (C). Survival time of corneal allografts was observed and routine assays were performed including immunohistochemistry, reverse-transcription polymerase chain reaction (RT-PCR), TdT-mediated dUTP nick end labeling (TUNEL). RESULTS: Survival time of corneal transplants was (14.3 +/- 1.3) days, (58.0 +/- 2.8) days, (106.3 +/- 17.5) days respectively. There was significant difference between groups in statistics analysis (P = 0.000). Inflammatory cells, predominant for CD4 + T cells, showed an increasing tendency for rejected corneal allografts in A group, peaked on postoperative 7 d and then decreased in C group compared with invisible in B group. CD80 or CD86 was detected on postoperative 3 d or 7 d respectively in excised cornea and iris of both A and B group, while either showed weakening expression in C group. On postoperative 14 d, IL-10, TNF-alpha, IFN-gamma mRNA were only detected in rejected cornea allograft of A group other than clear allografts of B or C group. Compared with no apoptosis in the other groups, abundant apoptosis cells were visible in cornea and iris of C group on postoperative 7 d. CONCLUSIONS: CTLA4-FasL is able to prolong survival time of corneal allografts by dual action mechanism to exert immunosuppressive effects, both blockade of CD28-CD80/86 pathway and induction of apoptosis of T cell.

Increased succinate receptor GPR91 involved in the pathogenesis of Mooren's ulcer.

AIM: To investigate the expression of succinate receptor GPR91 and its pathogenic roles in Mooren's ulcer (MU). METHODS: Biopsy specimens were obtained from 7 patients with MU and 6 healthy donors. The expression of GPR91 in MU tissues was evaluated using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). Succinate was used to activate GPR91 signaling, and the effect of GPR91 on the expression of interleukin-1ß (IL-1ß), NLRP3, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-13 (MMP-13) in human peripheral blood mononuclear cells (PBMCs) was determined. The influence of GPR91 on the nuclear factor-κB (NF-κB) signaling in PBMCs was investigated by detecting the phosphorylation of p65. Moreover, the expression of IL-1ß, VEGF, MMP-13 and phosphorylated p65 (p-p65) in the tissues of MU was examined by qRT-PCR or IHC. RESULTS: GPR91 mRNA expression showed a higher level in the MU group than in the healthy control group. IHC analysis also revealed that the expression of GPR91 was elevated in patients with MU compared with healthy controls. Moreover, ligation of GPR91 with succinate promoted the lipopolysaccharide-induced production of NLRP3, IL-1ß, VEGF and MMP-13 in PBMCs through increased phosphorylation of p65. Pharmacological inhibition of the NF-κB signaling reversed GPR91 induced production of NLRP3, IL-1ß, VEGF and MMP-13. These findings, coupled with the elevated amounts of IL-1ß, VEGF, MMP-13 and p-p65 observed in the MU biopsies, constituted a rational basis for the involvement of GPR91 in the pathogenesis of MU. CONCLUSION: This study indicates the increased succinate receptor GPR91 in conjunctival or corneal tissues is involved in the pathogenesis of MU through elevated NF-κB activity, which may provide a new therapeutic target for MU.

[The value of conjunctival flaps in the management of refractory corneal ulcer].

Refractory corneal ulcer, include infective, sterile and graft ulcer after corneal transplantation, is oppositional to the routine medical therapy and difficult to be managed with other methods. Among amniotic transplantation, corneal transplantation, and conjunctival flaps, which is the best way to treat the refractory corneal ulcer? This problem has puzzled the ophthalmic surgeons for a long time. This paper focused the indication and technique of conjunctival flaps, analyzed the results of some common refractory corneal ulcer treated by the conjunctival flap, and evaluated the value of conjunctival flaps in the management of the refractory corneal ulcer.

[The value of aetiology in the diagnosis of infectious keratitis].

Microbial keratitis is one of the major causes of blindness in China. The rapid and unequivocal identification of the causative organism is the key point for the rational antimicrobial therapy and restoration of the vision. It is difficult for the physician to choice the first step in the management of microbial keratitis: starting antimicrobial therapy after the identification of the causative organism, or starting therapy even there is no organism identification. The authors thought that it is urgent to start the antimicrobial therapy for microbial keratitis, however, the causative organism identification should be performed in time. This steps are necessary for the high diagnostic rate and cure rate of microbial keratitis, also for improving physician's consciousness of causative organism diagnosis.

[The indications and prognosis of penetrating keratoplasty in 236 children].

OBJECTIVE: To evaluate indications, surgical details, factors affecting graft survival and determinants of visual acuity after penetrating keratoplasty (PKP) in children. METHODS: This was a retrospective analysis of 266 grafts of PKP performed in 257 eyes of 236 children, aged younger than 14 years between June 1994 and June 2004 in Shandong Eye Institute and Qingdao Eye Hospital. The patient characteristics, indications, and outcome with follow up 6 months to 9 years and 5 months, mean (21 +/- 13) months were evaluated. RESULTS: On the basis of the corneal pathology, the indications of pediatric PKP were divided into three categories: related to congenital, hereditary and growth (99 eyes, 38.5%), related to trauma (82 eyes, 31.9%) and related to keratitis (76 eyes, 29.6%). At the last follow-up, the best corrected visual acuity of 146 eyes were better than 0.05, 37.7% (55/146) of these eyes were related to keratitis, and 55.5% (81/146) aged more than 9 years; 190 (190/266, 71.4%) of total grafts remained clear, in which, 52 (52/73, 71.2%) grafts were related to additional surgical procedures remained clear, 24 (24/48, 50.0%) were bilateral grafts and 8 (8/21, 38.1%) were repeat grafts. There was no significant difference between only PKP and PKP additional surgical procedures (chi(2) = 0.002, P = 0.965), and there was significant difference between the unilateral and bilateral grafts (chi(2) = 13.178, P = 0.000), between once and repeat PKP (chi(2) = 12.413, P = 0.000). CONCLUSIONS: The indications related to congenital, hereditary and growth are the main cause of pediatric PKP. The outcome is concerned with indications, ages onset, additional surgical procedures, bilateral grafts, and so on. Pediatric PKP is of benefit to children avoiding blindness caused by corneal opacity, especially combined with pre- and post-operative care.

[Ultrastructure changes in chronic corneal allograft dysfunction after penetrating keratoplasty].

OBJECTIVE: To study the ultrastructure changes of failed graft caused by chronic corneal allograft dysfunction (CCAD) after penetrating keratoplasty (PK), and to reveal the possible mechanism of these changes. METHODS: In CCAD group, corneas of 12 patients fulfilling the diagnostic criteria for CCAD who underwent repeated PK operation were studied. The average interval of these 12 patients between two PK operations was 69 months. All but two patients suffered at least once acute rejection episode during follow-up period. The mean time that the first acute immune rejection occurred was 39.4 months. Five healthy donor corneas were also studied as the control group. Both failed corneal grafts and healthy corneas were examined by light and electron microscopy. RESULTS: Compared with normal cornea, the cornea epithelium of CCAD became thinner, the quantity of microvillus apparently reduced, number of dark cells was increased, fibers of cornea stroma arranged disorderly, and there was no obvious invasion of inflammation cell into the stroma. The thickness of Descemet's membrane was uneven, abnormal lacuna and red cell could be seen between the Descemet's membrane and the endothelium. The number of cornea endothelial cells was decreased, cells became thinner, the organelle was reduced obviously, notch appeared in the cell nucleus, chromatin was condensed and inflammatory cells was adherent to the endothelium. CONCLUSIONS: The special ultrastructure changes of CCAD grafts consist of atrophic changes of the endothelium and fibrosis without inflammatory cells. Chronic subclinical alloantigen specific and non-alloantigen specific factors are both contributed to the CCAD process. Acute immune rejection perhaps induces and accelerates the occurrence and development of CCAD.