Limbal-conjunctival autograft transplantation for recurrent pterygium.

PURPOSE: To assess the usefulness of limbal-conjunctival autograft transplantation (LCAT) for the treatment of recurrent pterygium. PATIENTS AND METHODS: Seventeen eyes with advanced recurrent pterygium underwent LCAT All had already been treated at least twice either by simple excision (n=15) or by conjunctival rotation autograft (n=2). Three eyes (17.65%) had symblepharon at the time of surgery, so LCAT was combined with amniotic membrane transplantation. The autograft was taken from the supero-lateral part of the same eye and transferred to the area where the pterygium had been excised. RESULTS: During 6-18 months of follow-up no postoperative complications occurred. In 15 eyes (88.24%) no pterygium recurrence was recorded; recurrence occurred in two eyes (11.76%) after 8 and 5 months. In three eyes with a combined symblepharon formation, remission of both pterygium and symblepharon growth was obtained. CONCLUSIONS: LCAT seems to be a promising and safe procedure for recurrent pterygium.

Profile of cytokines in aqueous humor from corneal graft recipients.

AIM: Due to the immune privilege of the anterior eye chamber, the success rate of corneal transplantation can reach 90%. The aim of this study was to determine cytokine profile in aqueous humor of patients undergoing corneal transplantation, and to establish whether cytokine profile at the time of surgery influenced corneal graft outcome. METHODS: Proinflammatory (TNF-beta and IFN-gamma) and immunosuppressive (TGF-beta2) cytokine levels were measured in aqueous humor and serum of 44 patients. Non-inflammatory corneal diseases included keratoconus (n=8), bullous keratopathy (n=7), and stromal dystrophy (n=3). Inflammatory diseases included corneal scars (n=10), graft rejection (n=5), pending perforation (n=4), chemical burns (n=4), rejection/ uveitis (n=1), infectious keratitis (n=1), and perforated ulcer (n=1). Control aqueous humor and sera were obtained from cadavers without corneal pathology. RESULTS: The concentration of TGFbeta2 in the aqueous humor in non-inflammatory corneal diseases was similar to that of controls (2,605+/-204 pg/mL vs 2,200+/-100 pg/mL). In inflammatory corneal diseases, the concentration of TGFbeta2 in aqueous humor was significantly lower (1,400+/-375 pg/mL, p<0.001). TNF-beta was detected in the aqueous humor of 16 out of 26 patients with inflammatory corneal diseases and in all patients with stromal dystrophies, but was undetectable in cases of keratoconus and bullous keratopathy. Low levels of IFN-gamma were present in all aqueous humor samples. Patients' sera contained significantly less cytokine (up to 252 pg/mL) then their aqueous humor (p<0.001). We have set an arbitrary cut-off point for TGF-beta2 level in aqueous humor at 1,500 pg/mL and divided all investigated samples (from 44 patients and 10 controls) into two groups, one with high and the other with low TGF-beta2 concentration. The coefficient of contingency showed that patients with high TGF-beta2 concentration in their aqueous humor had significantly greater chance for graft acceptance than those with low TGF-beta2 concentration (p<0.001). CONCLUSION: High TGFbeta2 concentrations in the eyes without intraocular inflammation suggest its immunosuppressive role in human eyes. High concentration of TGFbeta2 (>1,500 pg/mL) was associated with graft acceptance. Also, absence of proinflamatory TNFbeta increased the graft acceptance, but independently from TGFbeta2.

The role of HLA-DRB1 matching in corneal grafting.

The aim of the study was to evaluate the role of HLA-DRB1 (Human Leukocyte Antigens) matching in corneal transplantation. Fifty-two patients were observed. Low-risk group consisted of 28 patients and high-risk group consisted of 24 patients. All the patients and donors were tissue typed with Polymerase Chain Reaction (PCR) on the HLA-DRB1 gen. The primary corneal disease preceding keratoplasty was keratopathia (15), leucoma (10), keratoconus (7), Re-KPP (6), impending perforation (4), combustio corneae (3), degenerative disorders (2), keratoglobus (1), keratouveitis (1), corneal maculae (1), and corneal melting syndrome (1). The graft rejection frequency was higher in the group of high-risk patients (29%) than in the group of low risk patients (7.1%). The rejection rate of compatible grafts was 37% for high risk and 2% for low risk group, while the rejection rate of incompatible was 44% in high risk and 5% in low risk group. We can conclude that HLA-DRB1 matching does not improve corneal graft survival.

Corneal transplantation in children.

The main purpose of the study was to describe the surgical success rate and visual results of penetrating keratoplasty in children. This retrospective study included children that underwent corneal transplantation at the Department of Ophthalmology, General Hospital "Sveti Duh", in the period 1994-1999. Patients' age ranged from 6 to 16 years. Twenty-five corneal transplants were performed in 24 eyes. Corneal pathologies were corneal leucoma, congenital dystrophy, corneal combustion, corneal scar after perforating injury, keratoconus, corneal melting, hematocornea and rekeratoplasty. The follow-up period was at least 6 months. The rate of graft survival was 1 year in 75% of eyes with congenital dystrophy and keratoconus. Hematocornea and rekeratoplasty ended with graft failure. Postoperative visual acuity improvement was recorded in 14 out of 25 eyes. Penetrating keratoplasty in children showed very good surgical success. The final visual outcome was affected by irreversible amblyopia.

Multilayer vs. monolayer amniotic membrane transplantation for deep corneal ulcer treatment.

The purpose of the study was to evaluate the efficacy of multilayer amniotic transplantation (AMT) for reconstruction of corneal stroma and epithelium. Corneal ulcer (28) was a consequence of a previous infectious or neurotrophic keratitis. In the first group (17) ulcer was covered with monolayer AM, while in the other group (11) there were two or more layers of AM situated in the ulcer and the whole cornea was covered with AM sheet. Monolayer AMT was successful in 64% while the multilayer AMT success rate was 72%. AM gradually dissolved within 3-6 postoperative weeks. AM transplantation facilitates rapid healing of corneal epithelium, reduces inflammation and stimulates epithelial cell regrowth. In eyes with deep corneal ulcer multilayer technique proved to be better then monolayer procedure.

Pterygium treatment with limbal-conjunctival autograft transplantation.

The objective of this pilot study was to examine the usefulness of limbal autograft transplantation (LCAT) in the treatment of recurrent pterygium. Eleven eyes with advanced recurrent pterygium underwent LCAT. All eyes were previously treated at least two times either by simple excision (10) or conjunctival rotation autograft (1). In two eyes (18.18%) symblepharon was present at the time of surgery, therefore LCAT was combined with amniotic membrane transplantation. Limbal-conjunctival autograft was taken from supero-lateral part of the same eye and transferred to the area where pterygium was excised. No intraoperative complications occurred. In ten eyes (90.9%) no pterygium recurrence was recorded during the follow-up time, and one (9.1%) recurrence was recorded after 5 months. In two eyes with combined symblepharon formation remission of both pterygium and symblepharon growth was obtained. LCAT proved to be a promising and safe procedure in recurrent pterygium treatment.

The influence of tissue culture on corneal immunogenicity.

In this study we examined whether immunization with heterotopic corneal graft can be suppressed by usage of cultured corneal tissue. Starting from the hypothesis that the corneal antigenicity might change during long-time storage, we compared, in a mouse model, the immunization obtained with fresh and> stored corneas. Heterotopic (chest wall) mice corneal allografts were exchanged between donors and hosts: (1) mismatched at multiple minor H loci and (2) only H-Y mismatched animals. Median survival time (MST) of primary and secondary skin grafts exchanged between mentioned donors and hosts was recorded. Recipient mice were immunized with either: (a) tail-skin graft, (b) fresh cornea graft or (c) corneal graft stored for three weeks in tissue culture. Three weeks later, recipients were challenged with skin graft placed at the opposite side of the chest wall and MST of these skin grafts was recorded. MST of secondary skin grafts in animals that had been immunized by skin served as a control. In case of multiple minor H disparity, MST of a first-set skin graft was 12 days, as compared to 9 days in case of secondary skin graft (P<0.05). MST of secondary skin graft following immunization by both fresh and stored corneas was 10 days. These data suggest that stored corneas don't loose ability to sensitize the multiple minor H disparate host. It also show that both cultured and fresh corneas, when placed in non-privileged site, have same immunizing capacity as skin (MST of 10 and 9 days, respectively; P>0. 1). When only H-Y disparate animals were used, MST of a first-set skin grafts was 26 days and of secondary skin graft 11 days (P<0.01). In case of H-Y disparity, MST obtained after immunization with fresh and stored corneal tissue (19 and 18 days, respectively) was significantly longer as compared to skin (P<0.05). However, no significant difference in MST of secondary skin grafts between recipients of fresh (19 days) and stored corneal grafts (18 days) was recorded. According to our results, the ability of corneal tissue to immunize both multiple minor H mismatched, as well as only H-Y mismatched host, was not influenced by storage in a tissue culture.

Human amniotic membrane in the reconstruction of the ocular surface.

We sought to determine the efficacy of amniotic membrane transplantation (AMT) in the reconstruction of ocular surface. AMT was performed on 40 eyes with following indications: I, persistent corneal ulceration (n = 12); II, impending perforation (n = 6); III, persistent epithelial defect on the corneal graft (n = 6); IV, recurrent pterygia (n = 10), and V, risk of conjunctival scarring (n = 6). Amniotic membrane was prepared from a fresh placenta under sterile conditions, washed with BSS containing penicillin, streptomycin, neomycin and amphotericin B and stored at -80 degrees C in 1:1 InoSol:Glycerol solution. Donor serological test for HIV, HBV and HCV were all negative. Associated surgical procedures according to indication were performed. Healing of the corneal ulcer in Group I was obtained in 67% of eyes at 1-3 weeks after surgery, Group II: AMT was followed by 'a chaud' keratoplasty in 33% and by planned keratoplasty in 67% patients, Group III: healing of the defect in 33% of eyes in 2-5 postoperative weeks, Group IV: no recurrence of pterygium ingrowth in 70% in the follow up period of 6-14 months, and V: 84% of patients had good eye motility without any synechia formation. We concluded that AMT have shown to be effective in enhancing healing of the corneal defects, in prevention of symblepharon formation and recurrent pterygium ingrowth. In case of impending perforation, AMT alone was not a method of treatment but is useful as a first step procedure in preparing the eye for the corneal transplantation.