G Sitalakshmi

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.

Cystoid macular edema after pediatric intraocular lens implantation: fluorescein angioscopy results and literature review

Purpose: To evaluate the occurrence of cystoid macular edema (CME) after lens extraction, anterior vitrectomy, and intraocular lens implantation (IOL) in children using angioscopy after administration of oral fluorescein. Setting: Centers in Tamil Nadu, India, and Hong Kong, China. Methods: This study comprised 18 children (28 eyes) who had cataract extraction, posterior capsulorhexis, anterior vitrectomy, and in‐the‐bag IOL implantation. The presence of CME was evaluated 1 week and 4 to 6 weeks after surgery using fluorescein angioscopy. Results: Anterior chamber fibrin occurred in 4 eyes (14.3%). Fluorescein angioscopy was performed 1 week after surgery in all eyes and after 1 month in 25 eyes (89.3%). No eye demonstrated the presence of CME on fluorescein angioscopy. Conclusions: Cystoid macular edema did not occur in the early period after pediatric cataract surgery using current surgical techniques. Longer follow‐up is required to ascertain the incidence of CME in the late postoperative period.

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.

CORNEAL TOPOGRAPHY IN ATYPICAL PELLUCID MARGINAL DEGENERATION

PURPOSE Pellucid marginal degeneration (PMD) is commonly described as a noninflammatory corneal ectasia typically involving the inferior cornea. Although reports of superior corneal changes in PMD exist, the topographic patterns of these PMD variants are not well characterized. We describe corneal topographic alterations seen in eyes with atypical PMD. METHODS Computer-assisted videokeratography was performed in 10 eyes of five patients with PMD. RESULTS Eight of the eyes studied had changes involving the superior cornea, with or without changes in the inferior cornea. Atypical presentations of PMD included extension of inferior peripheral thinning above the horizontal meridian and occurrence of superior corneal thinning and ectasia with or without typical inferior changes. Atypical PMD reveals topographic patterns similar to classic PMD, but corneal changes also involve the nasal, temporal, or superior quadrants or a combination of these. The topographic maps reflect the location of peripheral corneal thinning and extent of corneal protrusion. CONCLUSIONS Corneal topographic changes in atypical PMD are similar to those seen in typical PMD but can involve the superior cornea.

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.

Corneal autografting: a systematic approach.

OBJECTIVE To describe a systematic approach to corneal autografting. PATIENTS AND METHODS Retrospective review of case records of 3 patients who underwent this procedure. RESULTS All patients achieved satisfactory visual recovery. Oversized grafts of 0.5 mm had less post-operative complications in the recipient eye. A phakic blind eye that received a 0.5 mm undersized graft had a temporary ocular hypertensive phase. CONCLUSIONS Corneal autografting is a safe and effective technique in selected patients. The preferred surgical technique consists of surgery first on the blind eye, excision of a 0.5 mm oversized donor graft, cataract extraction if the eye is phakic, and use of an appropriate temporary keratoprosthesis to maintain donor eye integrity until autografting is completed in the eye with visual potential.

Partial flap during laser in situ keratomileusis: role of smaller diameter corneal flap of original thickness.

PURPOSE To report results of smaller diameter corneal flap of original thickness in the management of partial flap during laser in situ keratomileusis (LASIK). METHODS Retrospective review of the case records of three patients (3 eyes) who had a partial corneal flap during LASIK. RESULTS Retreatment was performed using an 8.5-mm-diameter corneal flap, which was smaller than the original partial flap of 9.5-mm diameter. The recut depth was maintained as the original cut depth of 160 microm. No intraoperative or postoperative complications were noted. At follow-up 4 weeks later, two patients had an uncorrected visual acuity of 20/20. One patient had uncorrected visual acuity of 20/40 that improved to preoperative best spectacle-corrected visual acuity of 20/30 with a correction of +0.50 -1.25 x 170 degrees. CONCLUSION A smaller diameter corneal flap of original thickness can be used for retreatment of partial flap during LASIK. A thicker posterior stromal bed after laser ablation may be retained with this technique, compared to retreatment using a corneal flap of greater thickness.