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.

Duplex RT-PCR for simultaneous detection of hepatitis A and hepatitis E virus isolated from drinking water samples

A duplex reverse transcription polymerase chain reaction (RT-PCR) protocol for simultaneous detection of hepatitis A virus (HAV) and hepatitis E virus (HEV) in water samples has been developed and demonstrated. Both HAV and HEV were concentrated from drinking water samples through a one-step concentration protocol. Different cDNA could be produced in the RT step carried out with a random primer in a single reaction tube. Two different sets of primers specific for HAV-cDNA and HEV-cDNA were used for PCR amplification. Amplified DNA products representing HAV and HEV were identified by gel electrophoresis at 247 and 327 bp (base pair) sequences, respectively. Specific sets of primers amplified a single type of virus and no cross-reactivity of the primers was noticed in duplex RT-PCR. The protocol was used for direct isolation and detection of HAV and HEV from 23 water samples in urban areas of Chennai city. Out of these, nine water samples were positive for HAV, and three for HEV. All three samples positive for HEV were also positive for HAV. The test provides a rapid and economical means of water quality surveillance to specifically detect HAV and HEV.

Corneal endothelial cell density and morphology in normal Indian eyes

PURPOSE

To describe corneal endothelial cell density and morphology in the Indian population and to compare endothelial cell characteristics in the Indian population with data available in literature for American and Japanese populations.

METHODS

Specular microscopy and corneal pachymetry were performed in both eyes of 537 normal Indian volunteers, aged 20-87 years. Parameters studied included endothelial cell density, cell area, coefficient of variation (CV) in cell area and hexagonality.

RESULTS

Mean endothelial cell density in the study population was 2,525 +/- 337 cells/mm2. There was a statistically significant decrease in endothelial cell density with age (p < 0.001, correlation -0.387) and the rate of cell loss was 0.3% per year. There was also a statistically significant increase in mean cell area (p < 0.001, correlation 0.362) and CV (p = 0.02, correlation 0.096), and decrease in percentage of hexagonal cells (p = 0.01, correlation -0.127) with increasing age. There was no significant difference in these parameters between fellow eyes of subjects. In all age groups, the mean endothelial cell density was significantly lower than values reported previously in the Japanese population. The values were less than those described in the American population, but the differences were statistically significant only in the 20-30 and 41-50 year age groups.

CONCLUSION

Normative data for the endothelium in the Indian population are reported. Endothelial cell density in Indian eyes is less than the values described in the Japanese and American populations.

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: 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.

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).

Understanding corneal topography

With the increase in corneal laser refractive surgery, there is a greater need for precise evaluation of the corneal surface. Articles published in the past year have reported possible use of confocal scanning laser technology-based devices to image the cornea. Other studies have compared existing instruments and software in an effort to determine if data from different instruments are comparable. Topographic evaluation also has served to highlight long-term complications of procedures like radial keratotomy and the promise of newer surgical procedures like the intrastromal corneal ring segments. Studies of the corneal surface have helped refine surgical procedures like photorefractive keratectomy, laser in situ keratomileusis, penetrating keratoplasty, and cataract surgery. Topographic measures that serve as direct correlates of ocular visual performance, however, still remain elusive. Studies in the past year have confirmed that corneal topographic evaluation may be a powerful tool in the search for a genetic basis of keratoconus. Important areas for future research include precise determination of the power of the postrefractive surgery cornea to allow precise estimation of intraocular lens power in these eyes. Detecting the presence of past corneal refractive surgery in donor eyes also is likely to be a challenge. Despite the numerous advances in the field of corneal topography in the past year, there is still a need to present the data in a standardized format that is universal to all instruments and technologies.

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.

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.

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.

In situ tumbling of the AcrySof intraocular lens

The small incision through which foldable acrylic intraocular lenses (IOLs) are implanted does not allow easy explantation of the lens in the event of intraoperative complications. Reversal of the IOL optic during insertion, although rare, can predispose to postoperative complications such as pupillary capture of the IOL, capsule bag distension syndrome, and refractive problems. Explanting the IOL can damage it, the cataract wound, or both. We describe a technique of in situ tumbling of the AcrySof IOL to correct reversed-optic implantation that preserves the integrity of the IOL and anterior segment structures.

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.

Explantation of silicone plate haptic intraocular lenses

The stress on small self-sealing incisions in cataract surgery has resulted in the increased use of foldable intraocular lenses (IOL). Plate haptic silicone IOLs implanted with the help of an injector require extremely small incision lengths and are extensively used. The authors discuss difficulties in explanting such lenses, especially in inflamed eyes. Two patients who underwent plate-haptic silicone IOL explantation for postoperative bacterial endophthalmitis are described. Plate haptic IOLs have a tendency to dislocate posteriorly because of poor capsular fixation and increased posterior bowing. Enlarging a small rhexis prior to attempting explantation of these lenses reduces this complication. Difficulties inherent in explanting plate haptic silicone IOLs in inflamed eyes are discussed, along with suggestions to overcome them.

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 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.

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.