Proliferative activity and p53 expression in primary and recurrent pterygia

PURPOSE: To assess p53 expression and proliferative activity in primary and recurrent pterygia from the same eyes. DESIGN: Retrospective comparative human tissue study. PARTICIPANTS: Tissue from excised primary pterygia that did not recur (group A, n = 10) was compared with tissue from primary pterygia that recurred (group B, n = 10) and to the recurrent pterygia tissue that was excised from subjects in group B (group C, n = 10). Ten normal conjunctivas served as controls (group D). METHODS: Sections from each pterygium were immunostained with the MIB-1 and bp53. 12 monoclonal antibodies that react with Ki-67 and p53 antigens, respectively. MAIN OUTCOME MEASURES: Proliferative activity was calculated as the mean of the MIB-1 positive cell count per eyepiece grid in high magnification (x40) (positive cell count/grid). Percentage of positive cells of all cells in the grid area was evaluated in the p53-stained sections. RESULTS: Proliferative activity was found in the epithelium overlying the pterygia and normal conjunctiva. The mean MIB-1 positive cell count/grid +/- standard error was 2.84 +/- 1.07, 1.74 +/- 0.82, 3.83 +/- 1.35, and 0.86 +/- 0.33 in groups A, B, C, and D, respectively (P = 0.17, Kruskal-Wallis). P53 staining was found in 50% of pterygia in groups A, B, and C; none of the normal conjunctival tissues showed p53 immunoreactivity. Four of five p53-positive tissues in group B were p53-negative in group C. In the p53-positive pterygia, less than 10% of cells were p53 positive. However, p53-positive pterygia had higher mean MIB-1 positive cell count/grid +/- standard error as compared with the p53-negative lesions, 4.56 +/- 0.94 vs 1.39 +/- 0.59 (P = 0.021, Mann-Whitney). CONCLUSIONS: p53 immunoreactivity and high proliferative activity in the epithelium overlying the pterygium are not associated with recurrence of pterygium.     

The relation between expression of basic fibroblast growth factor and mast cells in pterygium

OBJECTIVE: To examine the expression and distribution of basic fibroblast growth factor (bFGF) and mast cells in pterygium, and evaluate its effects in the pterygium formation and progression. METHOD: The expression of bFGF and mast cell tryptase in 17 primary pterygia, 6 recurrent pterygia and 6 normal conjunctival specimens were studied. The mast cell count and bFGF expression situation were observed. RESULTS: The bFGF was specifically localized in the epithelium, blood vessels and a subset of connective tissue cells. The bFGF expression was increased in the recurrent pterygium. The numbers of infiltrating mast cells (five 400 x sights) were (45.47 +/- 5.50) cells and (48.83 +/- 3.19) cells in the primary and recurrent pterygium respectively. In the comparisons between the cells in the pterygium (primary and recurrent) and (4.24 +/- 2.36) cells in the normal connective tissue, there were significant differences (F = 200.3128; q = 26.6762, 23.7341; P < 0.05). The shape and distribution of all the tryptase-positive cells (mast cells) in the pterygium tissues were similar to that of the cells with bFGF expression in the connective tissue. And the majority of bFGF-positive cells (87.54 +/- 3.60)% were similar to that of mast cells in the connective tissue. CONCLUSIONS: All infiltrating mast cells in pterygium have bFGF-positive expression. The bFGF expression is increased in the epithelium, blood vessels and infiltrating mast cells of the pterygium, and may contribute to the formation and progression of a pterygium.     

Conjunctival-limbal autografts for primary and recurrent pterygia: technique and results

Our technique of pterygium excision with conjunctival-limbal autografting is described and the safety and efficacy of the procedure in India is analysed. Case records of 51 consecutive patients (53 eyes) who underwent surgery at our institute between November 1992 and September 1994 were retrospectively analysed. Recurrence was defined as fibrovascular tissue crossing the corneoscleral limbus onto clear cornea in the area of previous pterygium excision. 2 (3.8%) of the 53 pterygia (primary 36; recurrent 17) recurred, after a mean follow up of 18.9 +/- 12.1 months (range: 1.5-43 months). Both recurrences occurred within a year of follow up, in patients who were < or = 40 years of age. No major operative or postoperative complications were encountered. The inclusion of limbal tissue in conjunctival autografts following pterygium excision appears to be essential to ensure low recurrence rates. The technique is safe, simple and inexpensive and is recommended for the management of both primary and recurrent pterygia in Indian eyes.     

Flow cytometry measurements of DNA content in primary and recurrent pterygia

PURPOSE: To evaluate DNA content and cellular proliferation rates in primary and recurrent pterygia. METHODS: Matched pterygium and superior conjunctiva tissue were obtained in 36 eyes of 36 patients undergoing pterygium excision with conjunctival autografting (24 primary pterygia, 12 recurrent pterygia). Epithelial and fibrovascular layers were separated for analysis. Matched superior conjunctiva obtained at the time of surgery were used as controls. Samples were prepared according to Thompson's method, and flow cytometry was performed with a Becton-Dickinson FACScan. Analysis of histograms and calculations of cell percentages in cell cycle phases were carried out using CellFit software (version 2.0). Mean proliferation indices (MPIs) were compared using the Wilcoxon matched-pair signed-rank test. RESULTS: The MPI of pterygium fibrovascular tissue (13.4) was significantly higher than the MPI of pterygium epithelium (3.1; P = 0.0001). The MPI of pterygium fibrovascular tissue was also significantly higher than that of superior conjunctival fibrovascular tissue (6.0; P = 0.0001). There was no difference in MPI values between pterygium epithelium and superior conjunctival epithelium (3.55; P = 0.12). The MPI of fibrovascular tissue from recurrent pterygium (73.75) was significantly higher than the MPI of fibrovascular tissue from primary pterygium (7.3; P = 0.003). CONCLUSIONS: The finding of high levels of cellular proliferation in the subepithelial fibrovascular layer of pterygium confirms that pterygium is a disorder of excessive cellular proliferation and that the fibrovascular layer is the site of cellular proliferation. Markedly raised levels of cellular proliferation in recurrent pterygium tissue suggest a clinical correlation between fibrovascular tissue upregulation and pterygium recurrence after surgery.     

翼状胬肉组织中环氧化酶-2及p21-ras的表达研究

目的 通过免疫组织化学方法检测翼状胬肉组织中环氧化酶-2（COX-2）和p21ras的表达，进一步证实氧自由基在翼状胬肉形成和发展中的作用。方法 选择临床切除的静止期、进行期和复发期胬肉材料共40例，行苏木精-伊红染色及COX-2和p21ras免疫组织化学染色。结果 COX-2及p21ras在正常球结膜中表达微弱，静止期胬肉组织中COX-2和p21ras阳性染色主要位于复层鳞状上皮化生细胞，在进行期及复发期翼状胬肉组织中COX-2及p21ras阳性染色弥漫性分布于复层鳞状上皮化生细胞的胞浆和杯状细胞的胞浆中，胬肉组织中的炎性细胞和血管内皮细胞胞浆可见少量COX-2及p21ras表达。结论 p21ras and COX-2的过度表达在翼状胬肉的发生和发展过程中可能起重要作用。     

Relationship between angiogenesis and lymphangiogenesis in recurrent pterygium

AIM: To examine the relationship between angiogenesis and lymphangigenesis in recurrent pterygia. METHODS: Tissues from 34 excised recurrent pterygia (including 12 Grade 1, 10 Grade 2, and 12 Grade 3) were involved in the study and tissues from 7 nasal epibulbar conjunctivae segments were used as controls. Sections from each pterygium were immunostained with CD₃₁ and LYVE-1 monoclonal antibodies to evaluate lymphatic microvessel density (LMVD) and blood microvessel density (BMVD), and the relationship between LMVD and BMVD in the pterygium was examined. RESULTS: There was a large number of CD₃₁⁽⁺⁾LYVE-1^(-) blood vessels but only a few CD₃₁⁽⁺⁾LYVE-1⁽⁺⁾ lymphatic vessels in grades 1 and 2 pterygium. However, lymphatic vessels were dramatically increased in grade 3 pterygium. LMVD correlated closely with BMVD in all pterygia, including grades 1, 2 and 3 peterygium patients (all P values <0.01). Although both the density of blood and lymphatic vessels increased in recurrent pterygia, lymphatic vessels developed much faster than blood vessels, especially in grade 3 pterygia. CONCLUSION: There is a significant but not parallel relationship between angiogenesis and lymphangiogenesis in recurrent pterygium. The outgrowth of blood and lymphatic vessels provide evidence that immunological mechanism may play a role in the development and recurrence of pterygium.     

A comparative study of recurrent pterygium surgery: limbal conjunctival autograft transplantation versus mitomycin C with conjunctival flap

OBJECTIVE: To compare the recurrence rate following treatment of recurrent pterygia using one of two techniques-limbal conjunctival autograft transplantation versus low-dose intraoperative mitomycin C (0.2 mg/ml) combined with conjunctival flap closure. DESIGN: Randomized clinical trial. PARTICIPANTS: Eighty-one patients with recurrent pterygia treated by limbal conjunctival autograft transplantation (n= 41) or mitomycin C combined with conjunctival flap (n= 40) participated. INTERVENTION: Limbal conjunctival autograft transplantation or low-dose intraoperative mitomycin C application with conjunctival flap technique was performed on recurrent pterygium cases. MAIN OUTCOME MEASURES: Recurrence of pterygium and postoperative complications. RESULTS: During mean follow-up periods of 16+/-1.9 and 15.5+/-1.5 months, six recurrences (14.6%) in the limbal conjunctival autograft transplantation group and five recurrences (12.5%) in the mitomycin C group were observed (P=0.77). The difference between the mean ages of recurrent (26.4+/-8.0 years) and nonrecurrent (35.8+/-11.9 years) cases for all patients was statistically significant (P=0.014). Technically, limbal conjunctival autograft transplantation seemed to be more difficult. The most frequent complication in limbal conjunctival autograft transplantation was graft edema, whereas that in the mitomycin C group was superficial keratitis. CONCLUSION: Both techniques showed similar recurrence rates in the treatment of recurrent pterygia. Although technically easier to perform, further follow-up is necessary to determine the long-term safety of low-dose intraoperative mitomycin C with conjunctival flap closure. The surgeon's familiarity with either procedure should determine the method of choice.     

Long-term follow-up study of mitomycin eye drops as adjunctive treatment of pterygia and its comparison with conjunctival autograft transplantation

We observed 48 patients for 7-21 months (mean, 18 months) after pterygium excision and 2 weeks of placebo or mitomycin topical therapy to evaluate whether or not the short-term efficacy of mitomycin in preventing pterygium recurrence would be reflected in long-lasting efficacy as well. Placebo-treated pterygia showed a 73% recurrence rate. One of 58 (1.7%) mitomycin-treated pterygia recurred (p less than 0.05). We also performed a pilot study comparing pterygia treated with excision followed by 0.4 mg/ml of mitomycin to pterygia treated with excision coupled with conjunctival autograft transplantation to estimate the number of patients required for a randomized clinical trial comparing these two treatment modalities and thereby to decide whether or not such a study would be justified. Thirteen primary and two recurrent pterygia were treated with mitomycin, while 14 primary and one recurrent pterygia were treated with conjunctival autograft transplantation. With mean follow-up times of 4 and 6 months, respectively, no recurrences were noted in the mitomycin-treated group, while the conjunctival autograft transplantation group had one recurrence (6.6%). We estimate that 400 patients would be required for a properly designed clinical trial comparing these two effective therapies for prevention of recurrent pterygia. We conclude that such a study is unjustified, and further conclude that the vastly less expensive, simple therapy of mitomycin eye drops is the more appropriate treatment.     

Expression of p63 and p16 in primary and recurrent pterygia

Background p63 and p16 have been described as stem-cell markers of squamous epithelium. In an attempt to obtain new insights into the pathogenesis of pterygium, this study aims to evaluate the relationship between p63 and p16 expression in primary and recurrent pterygia.Methods Samples of primary (n=56) and recurrent (n=14) pterygia and normal bulbar conjunctival tissue (n=11) were submitted to immunohistochemical study to evaluate the expression of p63 and p16 in these tissues.Results Most of the cells stained for p63 were located in the basal layer of the normal conjunctiva, in the lower two-thirds of the epithelium of primary pterygia, and throughout all epithelial layers of recurrent pterygia. In normal conjunctivae, p16 expression was rarely expressed. Primary and recurrent pterygium groups exhibited increased p16 expression, with cytoplasmic staining in the primary group, and cytoplasmic or nuclear staining in the recurrent group.Conclusion The overexpression of p63 and p16 observed in the present study reinforces likelihood of involvement of these genes in the pathogenesis of pterygium, perhaps related to the intense cellular turnover with substitution of superficial epithelial cells by less differentiated forms. This loss of normal cellular differentiation of the epithelial layers could explain the high rates of recurrence overall in the recurrent pterygia.Research supported by FAEPA and CAPES.     

Evaluation of loss of heterozygosity and microsatellite instability in human pterygium: clinical correlations

AIMS—To evaluate the incidence of loss of heterozygosity (LOH) and microsatellite instability (MI) in pterygia and their possible correlation with clinical variables.
METHODS—50 pterygia, blood, and conjunctival specimens were obtained. A personal and family history was recorded for each patient. Amplification of 15 microsatellite markers at regions 17p, 17q, 13q, 9p, and 9q was performed using the polymerase chain reaction. The electrophoretic pattern of DNA from pterygia was compared with the respective pattern from blood and conjunctiva.
RESULTS—LOH incidence was the highest at 9p (48%), followed by 17q (42%). Only three cases displayed MI. LOH incidence at individual markers was positively correlated with recurrence (D9S59, p=0.11 and D9S270, p=0.16), family history of neoplasia (D13S175, p=0.09), altitude of present residence ( D9S112, p=0.1), duration of the existence of pterygium (D9S144, p=0.06), and inversely correlated with age (D9S59, p=0.09). Concerning chromosome arms, LOH was positively correlated with the altitude of present residence (13q and 17p, p=0.03) and duration of the existence of pterygium (13q and 17p, p=0.09).
CONCLUSIONS—LOH is a common event whereas MI is a very uncommon one at the examined markers in pterygium, indicating the presence of putative tumour suppressor genes implicated in the aetiopathogenesis of the disease. The fact that LOH at 9q31-33 was more frequent in recurrent pterygia and also correlated with known risk factors such as young age and high altitude of residence, implies a possible predictive value of this finding for postoperative recurrence.

Keywords: heterozygosity; microsatellite instability; pterygium     

Randomised controlled study of conjunctival autograft versus amniotic membrane graft in pterygium excision

AIM: To determine whether amniotic membrane can be used as an alternative to conjunctival autograft after pterygium excision. METHODS: 287 eyes with either primary or recurrent pterygium were included in this study. All eyes were randomised to undergo conjunctival autograft or amniotic membrane transplantation after pterygium excision by a single surgeon. 106 eyes in primary pterygium and 14 eyes in the recurrent group were treated with conjunctival autograft, and 148 eyes in primary pterygium and 19 eyes in the recurrent group were treated with amniotic membrane transplantation. Patients were followed up at 6 weeks and 6 months after operation. The main outcome measurement was recurrence rate after surgery. RESULTS: In the conjunctival group, the recurrence rate was 12.3%, 21.4% and 13.1% for primary, recurrent and all pterygia, respectively. In the amniotic membrane group, the recurrence rate was 25.0%, 52.6% and 28.1% for primary, recurrent and all pterygia, respectively. The recurrence rate for all pterygia in the amniotic membrane group was significantly higher than that in the conjunctival group (p = 0.003). CONCLUSIONS: Amniotic membrane graft had a higher recurrence rate than conjunctival autograft. However, it is an alternative choice, especially for advanced cases with bilateral heads or patients who might need glaucoma surgery later.     

羊膜移植联合自体角膜缘干细胞移植对复发性翼状胬肉的效果分析

目的:探讨羊膜移植联合自体角膜缘干细胞移植术治疗复发性翼状胬肉的效果及其影响因素。方法:对复发的翼状胬肉患者行胬肉切除 羊膜移植 自体角膜缘干细胞移植术,观察术后植片情况、角膜创面愈合时间、取材区愈合情况和患者症状;随诊观察术后复发率。结果:28例(32只眼)复发翼状胬肉患者行胬肉切除 羊膜移植 自体角膜缘干细胞移植,随诊6~12个月,平均7.6个月,角膜创面上皮愈合时间为3~7d,平均(4.4±1.5)d;最后复诊时28例(32只眼)患者中4只眼复发,复发率为12.5%;所有患者取材区实现上皮化愈合。结论:翼状胬肉切除联合羊膜移植和自体角膜缘干细胞移植能有效地减少复发性翼状胬肉的术后复发;对角膜缘受累范围大的患者应注意医源性角膜缘干细胞损害的风险。眼科学报2007;23:227-230.     

Detection of 8-hydroxydeoxyguanosine enzyme in recurrent pterygium raising a question on its role on recurrence

AIM: To detect the presence of 8-hydroxydeoxyguanosine enzyme (8-OHdG) in recurrent pterygium and its role on recurrence. METHODS: Ninty-two samples were collected of which 55 from primary pterygium, 12 from recurrent and 25 from normal conjunctiva. A cross sectional study was embarked to detect the presence of the 8-OHdG enzyme in primary, recurrent pterygium and the normal conjunctival tissue by immunohistochemistry test. RESULTS: The immunohistochemistry test showed positive results: 35 in primary, 2 in recurrent pterygia and 4 in normal conjunctiva, respectively. Significant association between primary pterygium and 8-OHdG enzyme (63.6% of samples are positive) and no significant relation was detected with recurrent pterygium (16.7% of samples are positive). CONCLUSION: 8-OHdG enzyme is associated with primary pterygium. It is also present in normal conjunctival tissue. For the first time it is detected in recurrent pterygia. This may raise question whether 8-OHdG enzyme has a role in recurrence of pterygium.     

Telomerase activity and p53 expression in pterygia

PURPOSE: To investigate tolomerase activity and p53 expression in pterygial tissue. METHODS: Pterygia tissue was obtained during excisional surgery fr om 35 eyes of 35 patients, and superior bulbar conjunctival tissue from the same eye was also sampled as control when possible. Fluorescence telomeric repeat amplification protocol was used to measure telomerase activity in whole pterygium samples from 9 cases and in the epithelium and stroma of pterygium from another 10 cases. p53 protein content was measured by enzyme-linked immunosorbent assay (ELISA) in tissues obtained from 7 eyes, as well as in epithelial cell suspensions collected by brush cytology in 8 eyes. Six samples were also analyzed for UV-specific mutations in the p53 gene by the single-strand conformation polymorphism technique and DNA sequencing. A conjunctival epithelial cell line was irradiated with sublethal levels of UV-B to investigate whether telomerase activity can be induced in vitro. RESULTS: In all, 63% of pterygia samples demonstrated telomerase activity, whereas all 10 paired conjunctival control samples were negative (P = 0.05, chi-square test). Of the 10 samples in which telomerase activity was measured separately in the epithelium and stroma of pterygia, 5 samples were positive in the epithelium, only 1 of which had activity in the stroma. Average telomerase activity in positive samples was 18.44 +/- 8.77 U/microg protein, compared with telomerase activity measured in a carcinoma in situ patient (33.73 U/microg), and in an immortalized conjunctival epithelial cell line (50.72 +/- 15.55 U/microg). Telomerase activity was not upregulated in this cell line by UV-B exposure. All 6 pterygia samples tested for p53 mutations did not reveal the UV-specific mutations in exons 5, 6, 7, or 8. No statistical significance was observed in the pterygium or conjunctiva p53 protein levels in epithelial cells collected by brush cytology, while p53 protein level was lower in pterygia when measured in whole tissue samples. CONCLUSIONS: Telomerase activity was detected in some pterygia, mostly in the epithelium. Pterygia was not associated with an increase in epithelial p53 protein content measured by ELISA.     

Surgical treatment of pterygium: 24 cases of excision

Forty-two eyes (32 patients) with pterygia were treated with simple excision at the Ophthalmologic Clinic of University of Kinshasa during a four year period (from Jan. 1, 1983, to Dec. 31, 1986). The mean age of patients with pterygia was 36 years (range of 22 to 70 years). Nineteen (59%) patients were males and thirteen (41%) were females. Twenty (48%) pterygia affected right and left eyes and 9 (21%) pterygia affected the right eye and 13 (31%) the left eye. The pterygia were classified in four stages according to the degree of penetration from the surface of the cornea. Most of the excised pterygia were at stage one or two. With an average follow-up of six months (range, one to 34 months), 10 (24%) of the eyes had recurrences following their primary irrespective of the eye condition and the stage of advancement. Rate of recurrence of pterygium after primary excision was higher before the age of 40 years. The recurrences were also twice higher in females than in males. Excision of the recurrent pterygia indicated a recurrence rate of 100%. These results confirm that simple resection was not indicated for recurrent pterygium, which could be treated with an other surgical technique as previously recommended. The results of this study showed that the primary excision could be reserved only for pterygium at stage 1 or 2 after the age of 40 years.     

Cyclooxygenase-2 expression in primary and recurrent pterygium

Background: Pterygia are common, benign, fibrovascular, and infiltrative processes of the corneo-conjunctival junction of unknown pathogenesis. Cyclooxygenase-2 (COX-2) mediates the rate-limiting step in arachidonic acid metabolism. Extensive evidence indicates that the COX-2 prostanoid pathway is involved in inflammation. The aim of the study was to document the immunohistochemical expression of COX-2 in primary and recurrent pterygia. Materials and Methods: In this study, 21 primary pterygia and 12 recurrent pterygia from subjects undergoing pterygium surgery and six normal corneal-scleral tissue specimens were studied immunohistochemically for COX-2 expression. Results: COX-2 was expressed in primary pterygia and recurrent pterygia specimens. There was a statistically significant difference in COX-2 expressions in fibroblasts between primary and recurrent pterygium cases ( P = 0.001). There were statistically significant differences in COX-2 expressions in surface epithelium ( P = 0.028) and stromal inflammatory cells ( P =0.000) between control tissues and primary pterygia tissues. We also detected statistically significant differences in COX-2 expressions in surface epithelium ( P =0.000), stromal fibroblasts P =0.000 (stromal fibroblasts and inflammatory cells), vessels ( P = 0.027) and inflammatory cells ( P =0.001) between control tissues and recurrent pterygia tissues. Conclusions: This is the first study to document the expression of COX-2 in primary and recurrent pterygia. In our opinion after excision of pterygia, fibroblastic proliferation continues and this contributes to recurrence.     

Differential expression of matrix metalloproteinases and their tissue inhibitors at the advancing pterygium head

PURPOSE: Pterygia are a proliferative and inflammatory growth of limbal epithelial stem cell origin, characterized by corneal tissue invasion and extensive matrix remodeling including the destruction of Bowman's layer (BL). The purpose of this study was to determine the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) at the advancing pterygium edge. METHODS: Formalin-fixed, paraffin-embedded whole eyes (n = 11) with pterygia attached, were serially sectioned and analyzed immunohistochemically to determine the spatial distribution of four MMPs and three TIMPs. Tear samples were collected from other patients with pterygia (n = 11) and displayed by gelatin zymography. RESULTS: Collagenase-1 was expressed by pterygium epithelial cells, corneal stromal fibroblasts and pterygium fibroblasts that had migrated between the epithelium and BL at the advancing pterygium edge. Collagenase-3 and gelatinases A and B were detected in all pterygia, intensely staining columnar epithelial cells directly adjacent to the denatured BL. In addition, gelatinase A immunoreactivity was observed on BL. Immunoreactivity for TIMP-1 and -3 paralleled that of the gelatinases, with more intense staining in epithelial cells and fibroblasts where BL was absent. TIMP-2 was faintly detected in pterygium epithelial cells but intensely stained pterygium fibroblasts. Gelatinase B was the most abundant gelatinolytic enzyme present in tears, elevated approximately twofold in eyes with pterygia versus the contralateral control eyes. CONCLUSIONS: This investigation is the first to identify the expression pattern of MMPs and TIMPs at the advancing pterygium edge in specimens of human eyes and in tears derived from patients with pterygia. These enzymes may be responsible for the destruction of BL, and their pattern of differential expression suggests that each may play a selective role in the pathogenesis of pterygia.     

Fibrin sealant in corneal stem cell transplantation

PURPOSE: To determine if transplanted corneal epithelial stem cells are safely and efficiently attached to the deficient limbal niche with use of fibrin sealant. The primary outcome is measured with respect to the stability of the transplant, with secondary qualitative evaluations of inflammation, patient comfort, speed of operation, and incidence of complications. METHODS: This retrospective case study examined a total of 114 corneal stem cell reconstructions performed in 95 patients from 1996 to 2004 using corneal stem cells primarily, with a minority of amnion alone, or both. Fibrin sealant was used as the only technique of stem cell adhesion for limbal reconstruction for primary or recurrent pterygia and various stem cell-deficient diseases from 2000 to 2004. RESULTS: The fibrin sealant group showed 1 small recurrence of pterygium but no complications. With sutures, there were 3 recurrences in the pterygia group. After completion of all surgical procedures, all patients were free of pterygia. Miscellaneous stem cell deficiencies were included to demonstrate that corneal stem cell transplants can be used in other corneal procedures in addition to pterygia. CONCLUSIONS: Fibrin sealant alone effectively and safely attached corneal stem cell transplants to the limbal niche. The additional qualitative observations of a reduction in operation time, postoperative pain, and inflammation augurs for more extensive use of fibrin sealants in ophthalmology.     

Analysis of variation in success rates in conjunctival autografting for primary and recurrent pterygium

AIMS: To evaluate the success rates of conjunctival autografting for primary and recurrent pterygium performed in a tertiary ophthalmic centre. METHODS: The outcome of 139 cases with primary pterygia and 64 cases with recurrent pterygia who underwent excision with conjunctival autografting was retrospectively reviewed. Outcome was evaluated in terms of recurrence of pterygia onto the cornea. The recurrence rates were determined using Weibull survival functions, in a mixture model that included a component allowing for cure. The suitability of this model was verified using Turnbull's non-parametric method for interval censored data (1974). Estimated recurrence free probabilities were based on the fitted Weibull survival curves. RESULTS: Mean follow up was 8.4 months in the primary group, and 9.5 months for the recurrent group. 29 out of 139 cases of primary pterygia recurred (20.8%) while 20 out of 64 cases in the recurrent group (31.2%) recurred. Recurrence rates varied widely among surgeons, ranging from 5% to 82%. Recurrence rates were inversely related to previous experience in performing conjunctival grafting. The recurrence free probability was 84% at 3 months, 73% at 1 year for primary pterygia, and 80% at 3 months, 67% at 1 year for recurrent pterygia. There was no statistical difference in recurrence rates between primary and recurrent groups (p= 0.80). CONCLUSION: The success of conjunctival autografting for pterygium in this series varies widely, and may be related to a significant learning curve or differing surgical techniques for this procedure. This may account for the wide variation in reported success of this procedure in the ophthalmic literature.     

Z-shaped incision without epithelial resection in pterygium surgery

AIM: To introduce a novel surgical technique using a Z-shaped incision without epithelial resection in ophthalmic pterygia. METHODS: This was a prospective study. During pterygium surgery, all proliferative tissues were separated from the cornea and conjunctiva without resection of the tissues. The unaffected conjunctiva was incised in a Z-shape. The upper (or lower) conjunctival flap was sutured to the lower (or upper) normal conjunctiva on the limbal sclera, while the proliferative tissue was sutured to the upper conjunctiva (or lower) near the fornix. RESULTS: Ten patients with pterygia were eligible for this study. Eight patients with primary pterygia and 2 with recurrent pterygia were included. The age of patients at surgery ranged from 47 to 90y (average: 71.9y). Five patients each showed right and left-sided pterygia. The postoperative follow-up periods were from 8 to 78mo (average: 25.0mo). The surgery was successfully conducted and wounds were favorably reconstructed in all patients. The proliferative tissues sutured to the normal conjunctiva showed palor and attenuated neovessles, and never showed re-growth after surgery. Nine patients did not show recerrence. Recerrent pterygium was noted in 1 patient, but additional treatments were not required. CONCLUSION: The procedure involves the reconstruction of pterygial tissue and normal conjunctiva using a Z-shaped incision. The scleral limbal wound can be covered with non-affected conjunctiva without any excision of conjunctival epithelia in patients with primary or recurrent pterygia.