Prema Padmanabhan

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.

Wavefront-guided versus wavefront-optimized laser in situ keratomileusis: Contralateral comparative study

PURPOSE: To compare the outcomes of wavefront‐guided and wavefront‐optimized treatment in fellow eyes of patients having laser in situ keratomileusis (LASIK) for myopia. SETTING: Medical and Vision Research Foundation, Tamil Nadu, India. METHODS: This prospective comparative study comprised 27 patients who had wavefront‐guided LASIK in 1 eye and wavefront‐optimized LASIK in the fellow eye. The Hansatome (Bausch & Lomb) was used to create a superior‐hinged flap and the Allegretto laser (WaveLight Laser Technologie AG), for photoablation. The Allegretto wave analyzer was used to measure ocular wavefront aberrations and the Functional Acuity Contrast Test chart, to measure contrast sensitivity before and 1 month after LASIK. The refractive and visual outcomes and the changes in aberrations and contrast sensitivity were compared between the 2 treatment modalities. RESULTS: One month postoperatively, 92% of eyes in the wavefront‐guided group and 85% in the wavefront‐optimized group had uncorrected visual acuity of 20/20 or better; 93% and 89%, respectively, had a postoperative spherical equivalent refraction of ±0.50 diopter. The differences between groups were not statistically significant. Wavefront‐guided LASIK induced less change in 18 of 22 higher‐order Zernike terms than wavefront‐optimized LASIK, with the change in positive spherical aberration the only statistically significant one (P = .01). Contrast sensitivity improved at the low and middle spatial frequencies (not statistically significant) and worsened significantly at high spatial frequencies after wavefront‐guided LASIK; there was a statistically significant worsening at all spatial frequencies after wavefront‐optimized LASIK. CONCLUSION: Although both wavefront‐guided and wavefront‐optimized LASIK gave excellent refractive correction results, the former induced less higher‐order aberrations and was associated with better contrast sensitivity.

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.

Modified osteo-odonto keratoprosthesis--the Indian experience--results of the first 50 cases.

Purpose: To study the results of the modified osteo-odonto keratoprosthesis (MOOKP) surgery in bilateral end-stage ocular surface disorders. Methods: The MOOKP surgery is performed as a routine in 3 stages. Stage 1A involves removal of the iris and anterior vitrectomy with a corneal transplant if indicated. Stage 1B + 1C usually performed simultaneously involves harvesting the buccal mucosa and transplanting it onto the ocular surface along with fashioning of the osteo-odonto alveolar lamina. Stage 2 involves transplanting the osteo-odonto alveolar lamina to the eye 3 months later. Results: The MOOKP surgery was completed in 50 eyes of 47 patients with a mean follow-up of 15.38 months (range: 1-54 months). Anatomic success was achieved in 96% of the eyes. Functional success of visual acuity ≥20/60 was noted in 66% of eyes. Complications included oroantral fistula (6%), trophic mucosal alterations (8%), lamina exposure (central 6% and peripheral 8%), mucous membrane overgrowth (2%), hypotony (2%), expulsion of optic cylinder (4%), endophthalmitis (2%), glaucoma (20%), sterile vitritis (6%), and retinal detachment (2%). Conclusions: MOOKP is the keratoprosthesis of choice in bilateral end-stage ocular surface disorders in the Indian subcontinent. Complications do occur and have to be recognized and treated early.

Interface fluid after laser in situ keratomileusis

We report a case in which raised intraocular pressure (IOP) was associated with interface fluid after uneventful bilateral laser in situ keratomileusis (LASIK). The patient presented with diffuse lamellar keratitis in both eyes 3 weeks postoperatively that was treated aggressively with topical corticosteroids. A steroid-induced rise in IOP resulted in interface fluid accumulation and microcystic edema. Measurements with the Goldmann tonometer revealed an IOP of 3.0 mm Hg in both eyes. However, Schiotz tonometry recorded a pressure of 54.7 mm Hg in both eyes. Reduction in the dosage of topical corticosteroid and medical treatment of the raised IOP resulted in resolution of the microcystic edema and interface fluid accumulation. This case highlights the inaccuracies of IOP measurement after LASIK and the resulting complications.

Monochromatic aberrations in eyes with different intraocular lens optic designs.

PURPOSE To study the wavefront aberration profile of eyes with three different types of intraocular lenses (IOLs)--the Tecnis Z9000 (modified prolate surface design) (Pfizer, New York, NY), the Acrysof MA60BM (unequal biconvex optic) (Alcon, Ft Worth, Tex), and the Sensar Optiedge AR40e (equibiconvex optic) (AMO, Santa Ana, Calif)--in eyes following cataract surgery. METHODS This study was conducted in two parts. The first part was a randomized open study of 32 eyes of 16 patients who underwent bilateral phacoemulsification with a foldable IOL in the capsular bag. A Tecnis Z9000 IOL was implanted in one eye and an Acrysof MA60BM IOL in the fellow eye. The ALLEGRETTO WAVE Analyzer (Wavelight Laser Technologies AG, Erlangen, Germany) was used to measure ocular aberrations 2 weeks after surgery. A paired t test was used to compare each Zernike term from Z3(-3) to Z6(6) between fellow eyes (pupil diameter = 6 mm). In the second part of the study, the wavefront aberrations of 16 eyes that underwent an identical surgical procedure as in the first part of the study but had a Sensar Optiedge AR40e IOL implanted were studied and compared with eyes with the Tecnis Z9000 and Acrysof MA60BM IOLs. RESULTS The mean spherical aberration (Z4(0)) was statistically significantly lower in eyes with a Tecnis Z9000 IOL (Z4(0) = 0.07 +/- 0.12 microm) compared with eyes with an Acrysof MA60BM IOL (Z4(0) = 0.29 +/- 0.20 microm, P < .001) and with eyes with a Sensar Optiedge AR40e IOL (Z4(0) = 0.20 +/- 0.09 microm, P = .002). No statistically significant differences were noted in any of the Zernike terms between eyes with Acrysof MA60BM and Sensar Optiedge AR40e IOLs, or in the root-mean-square (RMS) of total higher order aberrations among the three IOL groups. CONCLUSIONS The implantation of a Tecnis Z9000 IOL produces a significant reduction in spherical aberration of the eye. No significant differences were noted in the wavefront profile between eyes with Acrysof MA60BM and Sensar Optiedge AR40e IOLs. No significant differences were found in the RMS of total higher order aberrations among the three IOL groups.

Wavefront aberrations in eyes with decentered ablations

PURPOSE: To compare the refractive and functional outcomes and wavefront profiles in eyes with decentered ablations and eyes with well‐centered ablations. SETTING: Medical Research Foundation, Chennai, Tamil Nadu, India. METHODS: This retrospective analysis comprised eyes with topographically diagnosed decentered ablations after laser in situ keratomileusis (LASIK). Refraction, contrast sensitivity, and ocular wavefront aberrations were measured preoperatively and 1 month postoperatively. The induced aberrations in these eyes were compared with those in eyes with well‐centered ablations. RESULTS: Forty‐six eyes (38 patients) had decentered ablations and 60 eyes (32 patients), well‐centered ablations. The mean decentration in the study group was 0.86 mm ± 0.29 (SD) (range 0.35 to 1.61 mm). There was no significant correlation between decentration and attempted refractive correction. There was, however, a statistically significant (P<.05) linear correlation between the distance of decentration and the magnitude of induced tilt (r = −0.31), coma (r = −0.41), and secondary astigmatism (r = 0.36). The induced changes in tilt, oblique astigmatism, vertical coma, and spherical aberration were statistically significantly higher in eyes with decentered ablations than in eyes with well‐centered ablations. A statistically significantly higher percentage of eyes (87%) with well‐centered ablations than eyes with decentered ablations (70%) had a postoperative uncorrected visual acuity (UCVA) of 20/20 or better. There was no significant difference in contrast sensitivity between groups. CONCLUSION: Eyes with decentered ablations had a significantly higher magnitude of induced aberrations and lower UCVA than eyes with well‐centered ablations.

Keratectasia in 2 cases with pellucid marginal corneal degeneration after laser in situ keratomileusis

&NA; We report 2 patients who experienced progressive blurring of vision following myopic laser in situ keratomileusis (LASIK) in 1 eye (Case 1) and bilaterally (Case 2). High against‐the‐rule astigmatism, associated with perilimbal thinning inferiorly, was seen on refraction in all eyes. Regional corneal pachymetry confirmed the peripheral corneal thinning inferiorly. Corneal topography revealed the typical features of pellucid marginal corneal degeneration (PMCD) in the untreated eye of Case 1. Advanced changes were noted in the fellow eye. The corneal topography findings in Case 2 were similar to those seen in PMCD. Patients with early PMCD may present to the refractive surgeon with a stable refraction, normal corrected visual acuity, and adequate central corneal thickness. Corneal topography data along with regional corneal pachymetry must be interpreted carefully to detect these cases. Laser in situ keratomileusis can lead to a rapid progression of PMCD.

Lacrimal Proline Rich 4 (LPRR4) Protein in the Tear Fluid Is a Potential Biomarker of Dry Eye Syndrome

Dry eye syndrome (DES) is a complex, multifactorial, immune-associated disorder of the tear and ocular surface. DES with a high prevalence world over needs identification of potential biomarkers so as to understand not only the disease mechanism but also to identify drug targets. In this study we looked for differentially expressed proteins in tear samples of DES to arrive at characteristic biomarkers. As part of a prospective case-control study, tear specimen were collected using Schirmer strips from 129 dry eye cases and 73 age matched controls. 2D electrophoresis (2DE) and Differential gel electrophoresis (DIGE) was done to identify differentially expressed proteins. One of the differentially expressed protein in DES is lacrimal proline rich 4 protein (LPRR4). LPRR4 protein expression was quantified by enzyme immune sorbent assay (ELISA). LPRR4 was down regulated significantly in all types of dry eye cases, correlating with the disease severity as measured by clinical investigations. Further characterization of the protein is required to assess its therapeutic potential in DES.

Diffuse lamellar keratitis: are meibomian secretions responsible?

drawn in the irrigation mode, with the aspiration port facing anteriorly since the capsular bag becomes loose and inadvertent posterior capsule capture may occur at this juncture. If the I/A probe is in the aspiration mode during withdrawal of the probe, an inadvertent posterior capsule tear may occur. We would like to highlight additional clues for complete removal of an OVD during phacoemulsification.