Tectonic corneal lamellar grafting for severe scleral melting after pterygium surgery

PURPOSE: To describe the technique and review the indications and success of tectonic corneal lamellar grafting for the management of severe scleral melts after pterygium surgery. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty cases of severe scleral necrosis after pterygium surgery (1993-1999). INTERVENTION: Tectonic corneal lamellar grafting. Surgery involved (1) removal of all devitalized or infected scleral tissue surrounding the melt; (2) use of lamellar or full-thickness donor corneal tissue, fashioned to fit the scleral defect exactly or a 0.25-mm diameter larger; and (3) placement of a pedicled or free conjunctival flap over the corneal lamellar graft. MAIN OUTCOME MEASURES: Eradication of progressive scleral necrosis, preservation of globe integrity, eradication of infection, and preoperative and postoperative visual acuity. RESULTS: Sixteen (80%) of 20 cases developed severe scleral necrosis that required tectonic surgery after bare sclera pterygium excision with mitomycin C or beta-irradiation. Surgery was also therapeutic to eradicate progressive infection in 6 cases of infective scleritis that did not respond to maximal medical treatment. Scleral melting presented 1 month to 20 years after initial pterygium surgery in healthy, immune-competent adults. Therapeutic and tectonic success was achieved in 19 cases (95%); in 1 case, recurrence of fusarium fungal infection led to severe graft necrosis and intraocular spread. Among the cases of infectious scleritis, three eyes required repeat lamellar grafting to successfully eradicate infection. CONCLUSIONS: Tectonic and therapeutic lamellar keratoplasty, combined with aggressive antibiotic therapy, preserved globe integrity and eradicated infection in cases of severe scleral melting after pterygium surgery.     

Penetrating keratoplasty vs. epikeratoplasty for the surgical treatment of keratoconus

PURPOSE: Penetrating keratoplasty and epikeratoplasty have been utilized in the surgical treatment of keratoconus. Comparison of the relative efficacy of each procedure in achieving visual outcomes has not been achieved due to limited numbers of cases and follow-up in previous series. METHODS: All patients who underwent either penetrating keratoplasty or epikeratoplasty for keratoconus between January 1987 and December 1997, and for whom at least 24 months of postoperative follow-up data for visual acuity was documented in the medical record, were included in this retrospective, nonrandomized, sequential comparative trial. The sole criteria for outcome in each group, as well as for comparison of the two groups, was Snellen visual acuity measured at the time of each follow-up with the presenting optical aid. RESULTS: Inclusion criteria were met for 443 eyes treated with penetrating keratoplasty and 161 eyes treated with epikeratoplasty. Mean follow-up was 4.3 years for penetrating keratoplasty and 4.5 years for epikeratoplasty. In each group, approximately 50% of the patients chose rehabilitation with optical correction with either spectacles or contact lenses and 50% chose no optical correction. Final median logMAR visual acuity for all patients, irrespective of means of visual rehabilitation, was 0.30 (20/40) for penetrating keratoplasty and 0.40 (20/50) for epikeratoplasty (P < .00005). In 209 penetrating keratoplasty and 77 epikeratoplasty eyes with optical correction, the final median logMAR visual acuity was 0.18 (20/30) for penetrating keratoplasty and 0.40 (20/50) for epikeratoplasty (P < .00005). The final median logMAR visual acuity in 234 penetrating keratoplasty and 84 epikeratoplasty eyes without optical correction was 0.48 (20/60) in both groups (P-value was not statistically significant). CONCLUSIONS: Although penetrating keratoplasty was statistically superior to epikeratoplasty with respect to visual outcome, results with epikeratoplasty were adequate to recommend its use as a surgical alternative in cases when it is not desirable to perform penetrating keratoplasty.     

Descemet stripping endothelial keratoplasty: effect of the surgical procedure on corneal optics

PURPOSE: To determine the changes in corneal optical performance after posterior lamellar corneal transplantation. DESIGN: Retrospective case series. METHODS: The anterior segment in four eyes of four patients who underwent Descemet stripping endothelial keratoplasty (DSEK) with cataract extraction and intraocular lens (IOL) implantation were imaged with the Visante anterior segment optical coherence tomography [OCT] (Carl Zeiss Meditec, Dublin, California, USA). The curvature of the posterior surface of the donor graft was compared with that of the host cornea, and corneal thickness was measured. RESULTS: All eyes had a hyperopic refractive error after surgery. The posterior corneal curvature after surgery was more than that before surgery. Average preoperative keratometry was 43.4 diopters (D), and after surgery, it was 42.8 D using keratometry. However, when the postsurgical corneal power was calculated using the Gaussian optics method, the average value was 40.8 D. CONCLUSIONS: The addition of a donor corneal graft to the posterior surface of decompensated corneas may lessen the effective optical power of the cornea and may have implications for IOL power calculations in these eyes.     

角膜胶原交联治疗角膜融解的研究进展

角膜胶原交联( corneal collagen cross-linking,CXL)技术是通过紫外光A和感光剂核黄素的光化学反应使角膜基质内胶原纤维形成共价键,从而增加胶原纤维机械强度、生物学稳定性及角膜抗扩张能力。角膜融解( corneal melting)是一种与自身免疫相关的非感染性角膜溃疡。我们对角膜融解发病机制、目前主要治疗手段及紫外光 A核黄素介导角膜胶原交联术基本原理、在角膜融解方面的实验和临床研究现状等问题进行综述。     

Immune-mediated corneal melting disease

Corneal melting disease is, as illustrated, a very severe problem for patients. Correct diagnosis and aggressive management is critical. Help from general physicians and rheumatologists as required is essential, given that the medications used have significant toxic effects.     

Tectonic grafts for corneal thinning and perforations

PURPOSE: To evaluate the success of tectonic grafts in cases of corneal thinning and perforations. METHODS: We performed 42 tectonic grafts in 41 eyes of 40 patients. Three types of tectonic grafts were used in our treatment protocol. These were (a) full-thickness grafts, (b) mushroom grafts, and (c) lamellar grafts. The parameters evaluated were indications, visual acuity, location, size and type of graft, postoperative outcome, and complications, if any. RESULTS: The most common indication for tectonic grafts was corneal thinning and perforation subsequent to infection (12 eyes) followed by those due to immunologic causes (six eyes) and trauma (six eyes). Twenty-four full-thickness tectonic grafts, nine mushroom grafts, and nine lamellar patch grafts were performed. Anatomical success was achieved in 35 of 41 (85.4%) eyes. Visual acuity of 6/24 or better was obtained in 29 of 41 (70.73%) eyes. The mean of best-corrected visual acuity (expressed in decimal) improved from 0.2 +/- 0.26 to 0.34 +/- 0.26 at an average follow-up of 10.83 +/- 6.27 months. The major complications were peripheral anterior synechiae in four eyes (9.76%) and graft melting in five eyes (12.2%). CONCLUSIONS: Tectonic graft is a useful therapeutic option in selected cases of corneal thinning and perforations because it effectively restores the integrity of the eye and allows acceptable visual rehabilitation.     

Blastoschizomyces capitatus keratitis and melting in a corneal graft

CASE REPORT: We present the first case, to our knowledge, of Blastoschizomyces capitatus keratitis and melting in a corneal graft. An 80-year-old man was treated for a large, severe corneal abscess and melting in the corneal graft of his right eye. Medical history was negative for hematologic disorders. Urgent penetrating keratoplasty was performed. COMMENTS: Corneal cultures grew B. capitatus. Systemic fluconazole and systemic and topical amphotericin B treatment were started. Three months after the last operation, no recurrence was observed and the graft remained clear. B. capitatus can rarely cause severe keratitis in patients even in the absence of hematologic disorders.     

深板层角膜移植-一种新的光学性角膜移植技术

深板层角膜移植适合于角膜基质异常及/或混浊但内皮健康者,其恢复角膜透明性的效果与穿透性角膜移植相当。这一手术的最大优点是能避免术后排斥反应、无须内皮健康的供体。经过多年的改进,手术技术已有明显进步,但仍存在操作难度较大、费时、受体基质去除不彻底、术中后弹力膜微穿孔的缺点。随着手术技术的进一步完善,临床上相当部分的穿透性角膜移植可被深板层角膜移植取代。(眼科,2006,15:156-158)     

Tectonic corneal graft for conjunctival rhinosporidiosis with scleral melt

A 16 year old girl presented with irritation and watering of the right eye for 3 months. On examination, the superior perilimbal sclera was ectatic with incarcerated uveal tissue covered by conjunctiva. The conjunctiva showed discreet, yellow white mucoid spots. Excision biopsy of the conjunctiva showed subepithelial spherules of sporangia containing numerous endospores, suggestive of rhinosporidiosis. Diathermy was applied to flatten the staphyloma. The ectatic area was covered with a corneal patch graft. The patient was started on prednisolone acetate eye drops and oral dapsone for 6 months. Corneal graft was well incorporated and conjunctivalized by 3 months. Since the graft was not seen within the palpebral aperture, there was good cosmetic result. The corneal graft had the added advantage of transparency which allowed visualization of the underlying tissue to diagnose early recurrence. There was no recurrence at 6 months.     

Pigmented corneal implants: a surgical treatment for iridectomy related optical complications

Initial evaluation in rabbits demonstrates that corneal implants made from prolene and nylon sutures flattened into strips appear promising as a means of covering diplopia or glare-inducing iridectomies. Two-month follow-up studies showed the implants to be well tolerated in the corneal stroma. Results of the studies suggest that black prolene films of 50 to 70 micrometers in thickness, contoured to follow the corneal curvature, would be the ideal configuration for such implants.     

非甾体类抗炎剂滴眼液与角膜融解

近年来滴用非甾体类抗炎剂(NSAIDs)滴眼液出现角膜融解的病例时有报道,其发生的可能机制包括NSAIDs对环氧酶的抑制、基质金属蛋白酶在角膜中表达的增高、角膜知觉的减退及其中所含防腐剂、溶剂与表面活性剂的毒性等。此外,其他相关危险因素如糖尿病、自身免疫性疾病及眼表疾病等也可能与该并发症的发生有关。     

A comparison of penetrating keratoplasty to epikeratoplasty in the surgical management of keratoconus

Of 40 patients intolerant to contact lenses, 47 eyes with keratoconus were surgically corrected with either epikeratoplasty (N = 31) or penetrating keratoplasty (N = 16). The percentage of eyes in both groups that had visual acuity of 20/40 or better with contact lenses at one year were equal (14 of 15 eyes [93.3%] in the penetrating keratoplasty group; 27 of 29 eyes [93.1%] in the epikeratoplasty group); however, the penetrating keratoplasty procedure resulted in a higher percentage of eyes that had visual acuity of 20/20 than the epikeratoplasty group (11 of 15 eyes [73%] compared with seven of 29 eyes [24.1%], respectively). Both procedures resulted in significant corneal flattening, with the penetrating keratoplasty group producing an average of 3 diopters more keratometric reduction than the epikeratoplasty group one year postoperatively. Although no irreversible graft failures occurred, five of 16 eyes (31%) in the penetrating keratoplasty group had graft reactions. No serious complications were noted in the eyes of the epikeratoplasty group. Both procedures were effective in the surgical management of keratoconus.