Rama Rajagopal

Limbal allografting from related live donors for corneal surface Reconstruction

OBJECTIVE To report the results of limbal allograft transplantation, from human leukocyte antigen (HLA)-matched and -unmatched related live donors, in patients with ocular surface disease due to chemical burns and Stevens-Johnson syndrome. DESIGN Retrospective, noncomparative case series. PARTICIPANTS Eight patients (nine eyes) with severe chemical burns (n = 7 eyes) and Stevens-Johnson syndrome (n = 2 eyes). INTERVENTION Recipient eyes were treated with excision of cicatricial tissues. Transplantation of superior and inferior limbal grafts was performed from related live HLA-matched (n = 7) and -unmatched donors (n = 2). Systemic cyclosporine was not used in any of the recipients. MAIN OUTCOME MEASURES Reconstruction of corneal surface epithelium, restoration of avascularity, increase in ocular comfort, and improvement in visual acuity. RESULTS With a mean observation period of 17.2 months, phenotypically corneal epithelium, decreased vascularization of the corneal surface, and improved ocular comfort were seen in seven (77.8%) eyes. In all seven eyes, gradual recurrence of peripheral corneal vascularization occurred during the follow-up period. Features of graft rejection developed in three (42.9%) of these seven eyes. In two eyes, limbal transplantation from HLA-unmatched donors failed to reconstitute the corneal surface. Limbal allograft transplantation resulted in visual acuity of 20/400 or greater in only two (22.2%) eyes at last follow-up. Corneal grafts performed 7 and 16 months after successful limbal transplantation in two eyes developed recurrent epithelial breakdown and superficial corneal scarring. None of the donor eyes in this study had any complication. CONCLUSION Transplantation of limbal tissue from related live donors successfully reconstructs the corneal surface in HLA-matched recipients. Recurrence of vascularization on long-term follow-up probably results from inadequate stem cell transfer, immune-mediated stem cell damage, or both. Limbal allografting is best performed by transplanting the entire limbus from a cadaveric donor eye with systemic immunosuppression of the recipient, even if the donor is HLA-compatible.

LIMBAL AUTOGRAFTING : COMPARISON OF RESULTS IN THE ACUTE AND CHRONIC PHASES OF OCULAR SURFACE BURNS

PURPOSE To compare outcomes of limbal autograft transplantation (LAT) in the acute and chronic phases of ocular surface burns. METHODS Retrospective analysis of case records of 16 consecutive patients who underwent LAT for ocular surface burns, at our institute, between April 1994 and March 1997. RESULTS Limbal autograft transplantation was successful in reconstructing the corneal surface and restoring ocular comfort in 15 (93.8%) eyes. Limbal autografting failed to reconstruct the ocular surface in one patient undergoing surgery 2 weeks after grade IV alkali burns. In 13 eyes with counting fingers or worse vision, functional success (visual acuity >20/400) was attained after LAT in nine (69.2%) eyes. Visual acuity > or = 20/80 was achieved in two (25%) of eight eyes undergoing surgery for a persistent epithelial defect (PED) and five of six (83.3%) eyes undergoing surgery after the epithelial defect had healed (p = 0.03). Nine patients underwent simultaneous superior and inferior limbal autografting. Mean epithelial healing time in six of these patients undergoing surgery in the acute phase of injury (<4 months) was 15+/-6.1 days. In three patients undergoing a similar procedure in the chronic phase of injury, the healing time was 8.3+/-6.7 days. CONCLUSIONS Limbal autograft transplantation is successful in reconstructing the corneal surface and restoring ocular comfort after ocular surface burns. Surgery in the acute phase of injury (<4 months), in the presence of a PED, could result in delayed corneal reepithelialization and poorer visual prognosis. If performed in the acute phase of injury, LAT should be performed after adequate limbal vascularization and resolution of surface inflammation in the recipient eye, avoiding graft placement over ischemic limbus.

Postoperative Mycobacterium chelonae endophthalmitis after extracapsular cataract extraction and posterior chamber intraocular lens implantation

OBJECTIVE To describe a case of postoperative endophthalmitis caused by Mycobacterium chelonae after extracapsular cataract extraction with posterior chamber intraocular lens implantation. DESIGN Interventional case report. METHODS The history and clinical presentation of a 66-year-old female patient, in whom a low-grade delayed-onset endophthalmitis and keratitis developed after extracapsular cataract extraction with posterior chamber intraocular lens implantation, is described. Microbiologic investigations of the scrapings of corneal infiltrate at the cataract incision site, aqueous humor and eviscerated material, and histopathologic study of eviscerated material and an enlarged cervical lymph node were performed. MAIN OUTCOME MEASURES The clinical, histopathologic, and microbiologic findings in a case of low-grade delayed-onset endophthalmitis. RESULTS Analysis of the direct smear of both the corneal infiltrate as well as the eviscerated material revealed acid-fast bacilli. M. chelonae was isolated from these specimens. Direct smear and culture of the aqueous humor were negative for bacteria (including mycobacteria) and fungus. Histopathologic examination of the eviscerated material showed a dense infiltration of polymorphonuclear leukocytes in the uveal tissue, extensive necrosis and hemorrhage, and exudates with hemorrhage in the vitreous cavity. Histopathologic examination of the lymph node revealed granulomatous inflammation with caseation necrosis, but did not reveal acid-fast bacilli. CONCLUSIONS M. chelonae, although infrequent, should be considered an etiologic agent of delayed-onset, postoperative endophthalmitis and early bacterial diagnosis should help in institution of appropriate therapy.

Bilateral corneal infiltrates after excimer laser photorefractive keratectomy

A 26-year-old man developed painless inferior subepithelial infiltrates away from the site of ablation in both eyes after excimer laser photorefractive keratectomy (PRK) for myopia. Clinical characteristics of the corneal infiltrates resembled staphylococcal-immune infiltrates. The condition responded to treatment with topical diluted steroids and antibiotics. There was no residual corneal scarring. The infiltrates did not affect the refractive outcome of the surgery. Recognition of this rare entity will help clinicians avoid aggressive investigative and treatment modalities that can affect the results of PRK.

Biosynthetic and functional defects in newly identified SLC4A11 mutants and absence of COL8A2 mutations in Fuchs endothelial corneal dystrophy

Late-onset Fuchs endothelial corneal dystrophy (FECD) shows genetic heterogeneity. Identification of SLC4A11 as a candidate gene for congenital hereditary endothelial dystrophy with similar corneal endothelial defects as FECD and reduced mRNA expression of SLC4A11 in the endothelium of FECD cases suggested that this gene may also be involved in pathogenesis of FECD. Mutations in SLC4A11 give rise to SLC4A11 protein marked by retention in the endoplasmic reticulum as a result of mis-folding. We screened 45 sporadic late-onset, 4 early-onset FECD patients and an early-onset autosomal dominant FECD family. We identified three previously unreported missense mutations: c.719G>C (p.W240S), c.1519G>A (p.V507I) and c.1304C>T (p.T434I) in unrelated individuals. These SLC4A11 mutants, expressed in HEK293 cells, had defects in either their cell surface expression or functional activity (rate of osmotically driven water flux). SLC4A11 mutations contribute to 11% (5/45) of sporadic late-onset FECD in the cohort studied. COL8A2, which causes some cases of early-onset FECD, was also screened in this cohort. No mutations were identified in COL8A2, in neither the late-onset cohort nor the early-onset family, suggesting genetic heterogeneity in this FECD family.

Bilateral penetrating keratoplasty--indications, results and review of literature.

Purpose: To analyze the indications, functional results, and rates of graft rejection and failure after bilateral penetrating keratoplasty (PK) in a major eye care hospital and research center in India. Methods: Retrospective review of the case records of 38 patients who underwent bilateral PK and had at least 6 months follow-up after cornealtransplantation in the second eye. Results: The mean age of the 38 patients (20 M, 18 F) was 35 ± 25 years (range, 0.5 to 79 years). Mean follow-up was 49 ± 23 months (range, 13.4 to 116.4 months) after surgery in the first eye and 31 ± 22 months (range, 6.6 to 103.6 months) after surgery in the second eye. The average time interval between surgery in the first and second eye was 18 ± 10 months (range, 0 to 38 months). The commonest indications for surgery were corneal dystrophies (50%),aphakic bullous keratopathy (21%), and keratoconus (11%). Postoperatively, secondary glaucoma occurred in 2 first and 3 second eyes. Best-corrected visual acuity at last follow-up was > 6/12 in 34% of first eyes and 50% of second eyes, and was > 6/60 in 26% and 18% of first and second eyes respectively. Allograft rejection occurred in 4 of the first eyes and 3 of the second eyes. The two-year graft survival rate in first eyes was 70% and in second eyes was 83%. Worse outcomes were noted in grafts performed for secondary endothelial failure. Earlier graft failure occurred in first eyes (54 ± 5 months) compared to second eyes (79 ± 10 months) (Logrank Test p = 0.2311).Conclusions: Bilateral penetrating keratoplasty has reasonable success in selected patients. Corneal transplantation in the second eye does not seem to increase the risk of graft rejection in either eye.

Ligneous Conjunctivitis: A Clinicopathologic Study of 3 Cases

The clinical, histopathologic features, and treatment outcomes in 3 patients with ligneous conjunctivitis are described. Bilateral, idiopathic membranes occurred in the palpebral conjunctiva in 2 patients. In 1 patient, unilateral conjunctival changes occurred in the bulbar conjunctiva, at the site of pterygium excision. Treatment included topical hyaluronidase, chymotrypsin, heparin, and cyclosporine and surgical excision with limited or no success. In one patient, conjunctival autografting from the normal fellow eye resulted in pseudomembrane formation at the donor site in the previously unaffected eye. Histopathological evaluation of excised membranes revealed the presence of amorphous eosinophilic hyaline material and chronic inflammatory cells. Immunohistochemical study revealed a predominance of T-lymphocytes. This case series confirms the recalcitrant clinical course of ligneous conjunctivitis. Conventional treatment modalities described in literature were not useful in the management of this condition. Surgical manipulation of the unaffected fellow eye in patients with unilateral disease can result in pathologic conjunctival changes, and is best avoided.

A Study on Isolation Rate and Prevalence of Drug Resistance among Microorganisms Isolated from Multiorgan Donor and Donor Corneal Rim along with a Report on Existence of bla NDM-1 among Indian Population

Purpose: To study the rate of isolation and prevalence of drug resistance among bacteria isolated from conjunctival swabs collected from multiorgan donor and Donor corneal rim specimens obtained from a tertiary eye hospital in South India. Methods: Donor corneal rims (DCR) and conjunctival swabs from multiorgan donors collected over a period of 6 months were screened for the prevalent species of bacteria and drug resistance associated with them against the first line of antibiotics by phenotypic methods and multidrug resistant isolates were further subjected for genotypic analysis. Results: Seventy-six DCR specimens were screened out of which 46 (60.5%) specimens showed bacterial growth, the predominant isolate being Coagulase negative Staphylococci, the rest 30 (39.5%) did not show any culture growth. All 42 (100%) conjunctival swabs collected from multiorgan donors were positive for bacterial culture, the prevalent species once again, being Coagulase negative Staphylococci. Among the other gram positive bacterial genus encountered were Streptococci, Bacillus, Diphtheroids and the gram negatives were Enterobacteriaceae and nonfermentors. Antibiotic resistance was significantly high among gram positive group. Seven (29.1%) gram negative isolates were positive for Extended Spectrum Beta Lactamases (ESBL’s) by conventional and molecular method. A blaNDM -1 carrying Acinetobacter baumannii was isolated from a multiorgan donor. Conclusion: Preexcision culture in multiorgan donor is necessary to prevent postoperative endophthalmitis. Preexcision culture and antibiotic susceptibility testing of bacterial isolates of DCR will aid in understanding antibiotic pattern as institution of correct antibiotic will prevent the emergence of postoperative endophthalmitis. Molecular methods help in reducing the turn-around time for understanding the drug resistance genotypes.

Analysis of candidate genes ZEB1 and LOXHD1 in late-onset Fuchs’ endothelial corneal dystrophy in an Indian cohort

ABSTRACT Background: Fuchs’ endothelial corneal dystrophy (FECD) is a complex degenerative disease of the corneal endothelium with genetic predisposition. Pathogenic rare variants have been identified in SLC4A11, LOXHD1, ZEB1, and AGBL1. Association of single nucleotide polymorphisms (SNPs) and CTG trinucleotide repeat expansions in the intron of TCF4 gene to FECD has been studied across multiple ethnicities. Recently, genome-wide association studies have also identified KANK4, LAMC1, and ATP1B1 as novel loci for FECD. Here, we report the contribution of ZEB1 and LOXHD1 genes in our sporadic late-onset FECD cohort. Materials and methods: In the experimental study, coding regions of ZEB1 and LOXHD1 were screened by Sanger DNA sequencing in 52 late-onset and 5 early-onset FECD cases of Indian origin, recruited at a tertiary eye care center. Further, bioinformatics analysis was done. Results: One reported missense mutation, c.2522A>C; p.(Q841P), and one variant of uncertain significance (VUS), c.619A>G; p.(S207G), were identified in the ZEB1 gene. One VUS, c.6413G>Ap.(R2138Q), was observed in LOXHD1. A 3D structural bioinformatic analysis of the missense variant in LOXHD1 predicted the variant to affect the structure–function relationship of the protein. Discussion: While mutations in ZEB1 contributed to 2% of the late-onset FECD cases, the exact role of the two VUS identified in ZEB1 and LOXHD1 in FECD pathogenesis needs to be studied.

Unusual ulcerative keratitis caused by Prototheca wickerhamii in a diabetic patient

The purpose of the study was to report a case of ulcerative keratitis caused by an unusual algae Prototheca wickerhamii in a diabetic patient. This study design was a case report. A 46-year-old male, who was a known diabetic for 3 years, had an injury to the left cornea with the sparks of fire from wielding at work that developed into an ulcerative keratitis over a period of next 3 months as the patient was not on any medication. Corneal scraping culture report and Vitek 2 system investigation result confirmed it to be a P. wickerhamii infection. The patient was started on intensive topical 1% voriconazole and 5% natamycin for 1 month and with no improvement subsequently underwent penetrating keratoplasty. No recurrence of infection postoperatively was noted. This opportunistic algae rarely known to cause human eye infections is so far reported in either patients with severe systemic immunosuppression causing posterior segment eye involvement or as postcorneal surgery infections. We report an ulcerative keratitis by P. wickerhamii in a diabetic patient post corneal trauma with no prior ocular surgery.