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Biomedical subjects

P Padmanabhan

Publications and source records attributed to P Padmanabhan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Fellow eye treatment in excimer photo refractive keratectomy.

PURPOSE: To describe symmetry of response in fellow eyes of patients undergoing photorefractive keratectomy (PRK) for myopia, analyse the risk factors leading to asymmetry in response and to determine if delayed treatment of the second eye increases safety and predictability of PRK. METHODS: Retrospective review of case records of 133 patients who underwent bilateral myopic PRK and had a minimum follow up of 6 months in both eyes. RESULTS: Postoperative uncorrected visual acuity, spherical equivalent (SE) refraction within +/- 1 D of emmetropia, best-corrected visual acuity (BCVA) and corneal haze were not significantly different in fellow eyes of patients undergoing PRK for myopia. Of 87 eyes in group 1 (myopia < 6 D), 96.6% had uncorrected visual acuity > or = 6/12, 89.7% were within +/- 1 D of emmetropia, none lost > or = 1 line BCVA, and none had haze > or = grade 3. Similar results for 98 eyes in group II (myopia 6 to 9.9 D) were 75.6%, 55.1%, 2.0% and 2.0% respectively. For 81 eyes in group III (myopia > or = 10 D) the results were 42.7%, 33.3%, 8.6%, and 4.9% respectively. Among 84 patients with similar preoperative myopia in both eyes, 54 (64.3%) patients had a postoperative SE difference < or = 1 D in fellow eyes. Risk factors for asymmetric response among fellow eyes included increasing preoperative myopia (p < 0.001) and dissimilar treatment technique in the two eyes (p = 0.03). Corneal haze did not increase significantly after the third postoperative month. CONCLUSION: This study demonstrates that considerable symmetry of response exists in fellow eyes of patients undergoing myopic PRK. Early PRK in the fellow eye of patients with < 6 D myopia is safe and allows quick visual rehabilitation of the patient. In patients with myopia > or = 6 D, a 3-month interval before treating the second eye may improve the safety of the procedure.

Adolescent↗
PubMed2000

Partial flap during laser in-situ keratomileusis: pathogenesis and timing of retreatment.

PURPOSE: To report the timing of retreatment and clinical outcomes in patients with a partial corneal flap during laser in-situ keratomileusis (LASIK), and to describe the causes of this complication. METHODS: Retrospective review of case records of four patients (4 eyes) who had a partial corneal flap during LASIK. RESULTS: The mean age of the four patients was 23 +/- 4.7 years, and mean preoperative spherical equivalent (SE) refraction was -9.1 +/- 3.1 D (range, -5.5 to -13 D). A 160 microns corneal flap was attempted during the initial treatment. Retreatment with a 180 microns corneal flap was performed at a mean of 5.1 +/- 1.6 weeks (range, 4 to 7.5 weeks) after the initial procedure. There were no intraoperative complications during retreatment. Post-LASIK mean SE refraction was -1.0 +/- 1.1 D (range, +0.38 to -2.0 D), after a mean follow up of 19 +/- 15.7 weeks (range, 7 to 42 weeks). Best spectacle-corrected visual acuity decreased in one eye from 6/5 to 6/6 and was maintained in the others. CONCLUSION: LASIK retreatment can be performed as early as one month after a partial flap, if the refraction is stable and a thicker corneal flap is created.

Adult↗
PubMed2000

Nocardia Asteroides keratitis: report of seven patients and literature review.

PURPOSE: To describe clinical features and treatment outcomes in patients with advanced Nocardia asteroides keratitis. METHODS: Retrospective review of case records of 7 patients with culture-proven Nocardia keratitis. RESULTS: Corneal infection occurred after corneal trauma in two patients, cataract surgery in three patients, penetrating keratoplasty in one patient and was associated with a silicone buckle element infection in one patient. Mean duration of infection at presentation was 33.4 days (7-75 days), and five patients had received prior treatment with corticosteroids. Six of seven patients had deep corneal suppuration at the time of presentation, clinically suggestive of mycotic keratitis. In two patients who had received prolonged corticosteroid therapy (> or = 45 days), the eyes could not be salvaged. Complete resolution of infection was achieved in all 4 eyes treated with topical fortified cefazolin eye drops (50 mg/ml).

Adolescent↗
PubMed1999

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.

Adolescent↗
PubMed1999

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 corneal transplantation 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.

Adolescent↗
PubMed1999

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.

Acids↗
PubMed1999

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.

Adult↗
PubMed1999

Combined phacoemulsification and penetrating keratoplasty.

To highlight indications, technique, and advantages of closed-chamber phacoemulsification and intraocular lens (IOL) implantation during penetrating keratoplasty for corneal opacities. Case reports of 2 patients who underwent combined phacoemulsification, IOL implantation and penetrating keratoplasty. The technique described allowed controlled capsulorrhexis, cataract removal and in-the-bag IOL implantation. Complications due to increased posterior pressure during open-sky extracapsular cataract were not encountered. The surgical technique described in this report can only be used in selected patients undergoing combined corneal transplant and cataract surgery. In this group of patients, however, the technique offers many intra- and postoperative advantages.

Corneal Diseases↗
PubMed1999

Excimer laser phototherapeutic keratectomy: indications, results and its role in the Indian scenario.

PURPOSE: To report indications, technique, and results of excimer phototherapeutic keratectomy (PTK), and describe possible reasons for the small numbers of such procedures performed in a referral institute in India. METHODS: Retrospective review of case records of 10 patients (11 eyes) who underwent excimer PTK at our institute between February 1994 and September 1997. RESULTS: Corneal scars were the most common indication for treatment. Best-corrected visual acuity (BCVA) improved in 6 eyes (mean: 2 lines of Snellen acuity). All eyes had BCVA > or = 6/12 after treatment. None of the patients experienced loss of BCVA after treatment. Unaided visual acuity improved in 3 eyes and decreased in 2 eyes. Change in spherical equivalent refraction > or = 1 diopter occurred in 77.8% of eyes after treatment. Treating central corneal scars resulted in a significant hyperopic shift in refraction. CONCLUSIONS: Excimer PTK is a safe and effective procedure for the treatment of superficial corneal opacities. Post-treatment ametropia may require further correction with optical aids. Inappropriate referrals, deep corneal scars, and cost of the procedure could have contributed to the small numbers of PTK performed at our institute. Improved understanding of procedural strengths and limitations could lead to increased use of this procedure, with satisfying results in selected patients.

Adolescent↗
PubMed1998

Posterior keratoconus. An expanded classification scheme based on corneal topography.

OBJECTIVE: The purpose of the study was to evaluate corneal changes in posterior keratoconus. DESIGN: A retrospective review. RESULTS: Distinct topographic patterns were identified. Generalized posterior keratoconus showed uniform corneal steepening. Localized central and paracentral posterior keratoconus showed corneal steepening, and localized peripheral posterior keratoconus showed corneal flattening overlying the area of corneal change. The changes in central and paracentral posterior keratoconus appear to progress with an increase in patient age. Unilateral disease may have more amblyogenic potential. CONCLUSIONS: Posterior keratoconus manifests significant corneal surface alterations. The distinct topographic patterns seen probably warrant a further classification of localized posterior keratoconus into central-paracentral and peripheral varieties.

Adult↗
PubMed1998

Capsulorhexis in eyes with phacomorphic glaucoma.

Phacomorphic glaucoma is a common condition in developing countries. Extracapsular cataract extraction with a sulcus-fixated intraocular lens (IOL) is associated with increased intraoperative and postoperative complications in this condition. We developed a technique that allows a safe, controlled capsulorhexis in the presence of the shallow anterior chamber, increased anterior capsule convexity, and high intralenticular pressure seen in eyes with phacomorphic glaucoma. The intumescent cataracts are decompressed by filling the anterior chamber with viscoelastic; a 30 gauge needle is then used to aspirate liquid cortex, which facilitates a controlled capsulorhexis. This allows safe phacoemulsification of the cataract and in-the-bag IOL implantation.

Anterior Chamber↗
PubMed1998

Corneoscleral epithelial cysts: evidence of developmental etiology.

PURPOSE: To describe the clinical features, histopathology, surgical management and possible etiopathogenesis of corneoscleral epithelial cysts. METHODS: Three patients with corneoscleral epithelial cysts underwent surgical ablation of the cysts. Material obtained during surgery was subjected to histopathologic analysis. RESULTS: At last follow-up (mean, 6.3 months), none of the cysts had recurred. All patients had improved visual acuity. Histopathology revealed the occurrence of glandular elements suggestive of lacrimal tissue in one of the cysts. CONCLUSION: The presence of ectopic lacrimal tissue suggests a developmental etiology for such cysts. Marsupialization of the scleral portion of the cyst and chemical ablation of the lining epithelium of the corneal cyst with 20% trichloroacetic acid appears to be a safe and effective technique in the surgical management of corneoscleral epithelial cysts.

Child↗
PubMed1998

Conjunctival-limbal autografts for primary and recurrent pterygia: technique and results.

Our technique of pterygium excision with conjunctival-limbal autografting is described and the safety and efficacy of the procedure in India is analysed. Case records of 51 consecutive patients (53 eyes) who underwent surgery at our institute between November 1992 and September 1994 were retrospectively analysed. Recurrence was defined as fibrovascular tissue crossing the corneoscleral limbus onto clear cornea in the area of previous pterygium excision. 2 (3.8%) of the 53 pterygia (primary 36; recurrent 17) recurred, after a mean follow up of 18.9 +/- 12.1 months (range: 1.5-43 months). Both recurrences occurred within a year of follow up, in patients who were < or = 40 years of age. No major operative or postoperative complications were encountered. The inclusion of limbal tissue in conjunctival autografts following pterygium excision appears to be essential to ensure low recurrence rates. The technique is safe, simple and inexpensive and is recommended for the management of both primary and recurrent pterygia in Indian eyes.

Adult↗