Jayesh Vazirani

Keratoconus: current perspectives

Keratoconus is characterized by progressive corneal protrusion and thinning, leading to irregular astigmatism and impairment in visual function. The etiology and pathogenesis of the condition are not fully understood. However, significant strides have been made in early clinical detection of the disease, as well as towards providing optimal optical and surgical correction for improving the quality of vision in affected patients. The past two decades, in particular, have seen exciting new developments promising to alter the natural history of keratoconus in a favorable way for the first time. This comprehensive review focuses on analyzing the role of advanced imaging techniques in the diagnosis and treatment of keratoconus and evaluating the evidence supporting or refuting the efficacy of therapeutic advances for keratoconus, such as newer contact lens designs, collagen crosslinking, deep anterior lamellar keratoplasty, intracorneal ring segments, photorefractive keratectomy, and phakic intraocular lenses.

Autologous simple limbal epithelial transplantation for unilateral limbal stem cell deficiency: multicentre results

Purpose To report outcomes of autologous simple limbal epithelial transplantation (SLET) performed for unilateral limbal stem cell deficiency (LSCD) at multiple centres worldwide. Methods In this retrospective, multicentre, interventional case series, records of patients who had undergone autologous SLET for unilateral LSCD, with a minimum of 6 months of follow-up, were reviewed. The primary outcome measure was clinical success, defined as a completely epithelised, avascular corneal surface. Kaplan–Meier survival curves were constructed and survival probability was calculated. A Cox proportional hazards analysis was done to assess association of preoperative characteristics with risk of failure. Secondary outcome measures included the percentage of eyes achieving visual acuity of 20/200 or better, percentage of eyes gaining two or more Snellen lines and complications encountered. Results 68 eyes of 68 patients underwent autologous SLET, performed across eight centres in three countries. Clinical success was achieved in 57 cases (83.8%). With a median follow-up of 12 months, survival probability exceeded 80%. Presence of symblepharon (HR 5.8) and simultaneous keratoplasty (HR 10.8) were found to be significantly associated with a risk of failure. 44 eyes (64.7%) achieved a visual acuity of 20/200 or better, and 44 eyes (64.7%) gained two or more Snellen lines. Focal recurrences of pannus were noted in 21 eyes (36.8%) with clinical success. Conclusion Autologous SLET is an effective and safe modality for treatment of unilateral LSCD. Clinical success rates and visual acuity improvement are equal to or better than those reported with earlier techniques.

Unilateral partial limbal stem cell deficiency: contralateral versus ipsilateral autologous cultivated limbal epithelial transplantation.

PURPOSE To report the outcomes of autologous cultivated limbal epithelial transplantation using the healthy part of the affected eye or the fellow eye as a source of limbal stem cells in patients with unilateral, partial limbal stem cell deficiency (LSCD). DESIGN Retrospective, nonrandomized, interventional case series. METHODS setting: L. V. Prasad Eye Institute, Hyderabad, India. study population: Patients with unilateral, partial LSCD who underwent autologous cultivated limbal epithelial transplantation between 2001 and 2011. intervention: The limbal biopsy was taken either from the healthy part of the limbus of the same eye (ipsilateral group) or from the healthy fellow eye (contralateral group). Cells were cultivated using a xeno-free explant culture technique, and cultivated cells were transplanted onto the affected surface. primary outcome measure: Success of cultivated limbal epithelial transplantation, defined as a completely epithelialized, avascular, and clinically stable corneal surface. RESULTS Seventy eyes of 70 patients were studied. The mean follow up was 17.5 ± 7 months. In 34 eyes the limbal biopsy was taken from the ipsilateral eye and in the remaining 36 eyes from the contralateral eye. Clinical success was achieved in 70.59% of eyes in the ipsilateral group and 75% of eyes in the contralateral group (P = .79). Limbal transplant survival rates at the final follow-up visit were 65.1% ± 0.09% in the ipsilateral group and 53.6% ± 0.12% in the contralateral group (P = .74). CONCLUSIONS Ocular surface restoration in partial LSCD is possible with cell-based therapy. Outcomes are similar irrespective of whether the limbal biopsy is taken from the healthy part of the ipsilateral eye or the contralateral eye.

Multidrug-Resistant Pseudomonas aeruginosa Keratitis: Risk Factors, Clinical Characteristics, and Outcomes.

PURPOSE To identify risk factors for multidrug-resistant Pseudomonas aeruginosa (MDR-PA) keratitis and to report clinical characteristics and outcomes of this infection. DESIGN Retrospective, case-control study. PARTICIPANTS Ninety episodes of P. aeruginosa keratitis from a tertiary care eye institution from 2007 through 2014 were identified. Episodes of MDR-PA keratitis were taken as cases. Episodes of drug-sensitive P. aeruginosa keratitis during the same period were taken as controls. METHODS Chart review of cases and controls. Multidrug resistance was defined as resistance to 3 or more classes of antimicrobial drugs. Logistic regression analysis was used to determine association of baseline characteristics with multidrug resistance. Clinical characteristics and risk factors in each group also were compared. MAIN OUTCOME MEASURES Risk factors for multidrug resistance, including age, gender, eye, duration of symptoms, topical steroid or lubricant ointment use, trauma, prior ocular surgery, presence of a compromised ocular surface, and bandage contact lens use. RESULTS Twenty-three episodes of MDR-PA keratitis (cases) and 67 episodes of drug-sensitive P. aeruginosa keratitis (controls) were identified. In the multivariate analysis, lubricant ointment use, presence of a compromised ocular surface, and bandage contact lens use were associated with MDR-PA keratitis. Antimicrobial resistance in the MDR-PA keratitis isolates was least for colistin and imipenem (56.52% each). Corneal perforation was more common in cases (52.17% [12 of 23]) than in controls (11.94% [8 of 67]; P = 0.0001). Cyanoacrylate glue application was required in 47.82% of cases (11 of 23), compared with 22.38% of controls (15 of 67; P = 0.031). Keratoplasty was more commonly required in cases (47.82% [11 of 23]) than in controls (20.89% [14 of 67]; P = 0.017). CONCLUSIONS Lubricant ointment use, a compromised ocular surface, and bandage contact lens use are associated with MDR-PA keratitis. Preservative-free lubricant ointment may act as a source or reservoir of infection. Outcomes are worse in MDR-PA keratitis compared with drug-sensitive P. aeruginosa keratitis.

Role of topical, subconjunctival, intracameral, and irrigative antibiotics in cataract surgery.

Purpose of review To summarize current understanding of antibiotic prophylaxis in cataract surgery, with particular emphasis on available evidence and change in practice patterns over the past decade. Recent findings Povidone–iodine application prior to cataract surgery remains a universal practice, and is backed by good quality evidence. Subsequent to the results of the European multicenter trial documenting decreased risk of endophthalmitis with intracameral cefuroxime injection at the end of surgery, similar benefit with intracameral antibiotic use has been reported in studies with large sample sizes from multiple centers around the world. There has been a distinct change in practice patterns in many countries, with intracameral antibiotic use becoming part of routine protocol. In the USA, topical fluoroquinolone application remains the most popular mode of antibiotic prophylaxis. A promising approach is the development of novel drug delivery methods like polymeric devices designed for sustained antibiotic release. Summary Based on current evidence, the recommended measures for endophthalmitis prophylaxis are preoperative topical instillation of povidone–iodine and intracameral antibiotic injection at the end of cataract surgery.

Surgical Management of Bilateral Limbal Stem Cell Deficiency

Limbal stem cell deficiency (LSCD) is now established as a distinct entity with a spectrum of clinical manifestations. Bilateral LSCD presents a unique set of challenges to the clinician dealing with ocular surface disease, due to the underlying causes, clinical presentation, and adnexal status, as well as lack of a source of autologous limbal stem cells. Various surgical modalities have been described to achieve visual rehabilitation in patients with bilateral LSCD. These can primarily be divided into cell-based therapies and implantation of keratoprostheses. In this review, the surgical options for management of bilateral LSCD, including autologous and allogeneic cell-based therapies and different types of keratoprostheses are described and classified. The indications, prerequisites, technique, results and complications of each modality are discussed. Based on the status of the ocular surface, an algorithm for choosing appropriate surgical management for vision restoration in bilateral LSCD has been proposed.

Successful simple limbal epithelial transplantation (SLET) in lime injury-induced limbal stem cell deficiency with ocular surface granuloma

A 9-year-old boy presented with unilateral, total limbal stem cell deficiency (LSCD) complicated by the presence of a large fibro-vascular ocular surface mass lesion secondary to accidental lime injury. The pathological tissue covering the cornea was excised and simple limbal epithelial transplantation (SLET) was performed using autologous limbal tissue from the fellow eye. Histopathology of the excised ocular surface tissue revealed exuberant granulation tissue interspersed with retained calcium particles. At 6 weeks postoperatively, a focal recurrence of LSCD with symblepharon and forniceal shortening was noted superiorly. This was successfully managed by performing conjunctival autografting along with supplemental SLET. The unaided vision had improved from light perception at presentation to 20/40 at 6 months postoperatively. The fornices were deep and the corneal surface was avascular, epithelised and stable. This case demonstrates the efficacy of SLET in a child with severe ocular burns, highlighting the role of supplementary procedures customised to treat focal recurrences of LSCD.

Customised simple limbal epithelial transplantation for recurrent limbal stem cell deficiency

A 4-year-old boy developed unilateral, total limbal stem cell deficiency (LSCD) following an acid injury. A stable ocular surface was achieved with autologous simple limbal epithelial transplantation (SLET), performed 4 months after the injury. Focal areas of conjunctivalisation were noted in the postoperative period. These were addressed using a novel modification of SLET. A very small piece of limbus from the healthy eye was split into multiple pieces, and applied to the bare corneal stroma with fibrin glue after pannus resection. The surface was covered with amniotic membrane. This resulted in a stable surface, and visual acuity improved to 20/50. The donor remained healthy despite two biopsies being harvested. This case demonstrates that early ocular surface reconstruction may be considered in children with LSCD if amblyopia is a concern. Customised SLET allows surgeons to tackle focal recurrences of LSCD effectively, using minimal limbal tissue from the donor site.

Can we apply the results of the Steroid Corneal Ulcer Trial to Nocardia infections of the cornea

Evaluation of: Lalitha P, Srinivasan M, Rajaraman R et al. Nocardia keratitis: clinical course and effect of corticosteroids. Am. J. Ophthalmol. 154(6), 934.e1–939.e1 (2012). The authors compared the clinical course of Nocardia species keratitis with keratitis resulting from other bacterial organisms and also the effect of corticosteroids as adjunctive therapy. This was a subgroup analysis using data collected from the Steroid Corneal Ulcer Trial wherein 500 patients with culture‑proven bacterial keratitis were randomized 1:1 to topical corticosteroid therapy or placebo after receiving topical moxifloxacin therapy for at least 48 h. Fifty five patients presented with Nocardia keratitis and the data from these patients were used for the subgroup analysis. The authors analyzed various aspects of Nocardia keratitis and compared several features with non-Nocardia keratitis cases. Since 31 subjects of the subgroup were randomized to corticosteroid therapy and 23 to the placebo group, the data could be used to study the effect of corticosteroids for Nocardia keratitis. The key findings of this study were as follows: trauma was the most common predisposing factor for this infection, and nearly half of the enrolled subjects were agricultural workers; the patients with Nocardia ulcers had longer duration of symptoms (median duration of 10 vs 4 days for non-Nocardia cases); despite longer duration of symptoms, the patients had better presenting visual acuity (median Snellen visual acuity 20 out of 45 compared with 20 out of 145 for non-Nocardia cases) while the infiltrate size remained the same (median infiltrate size: 2.7 mm); the most common species were Nocardia cyriacigeorgica (35%), Nocardia pneumoniae (21%) and Nocardia asteroides (19%); 98% of the Nocardia species were susceptible to amikacin while fluoroquinolones showed variable activity; median best spectacle corrected visual acuity and infiltrate or scar size at 3 months were comparable with non-Nocardia keratitis cases; on average, the use of corticosteroids was associated with a 0.40-mm larger infiltrate or scar size at 3 months in Nocardia keratitis cases, however, there was no difference in the time to re‑epithelialisztion and rate of corneal perforation. The authors concluded that Nocardia keratitis generally responds well to antibiotic therapy, but the adjunctive use of corticosteroids results in larger infiltrate or scar sizes, suggesting that this therapy may not be appropriate for treating this disease.

Conjunctival pedicle flap in management of open globe injury with corneal tissue loss

Accidental injury with scissors led to an open globe injury with iris prolapse and corneal tissue loss in the right eye of a 15-year-old girl. Attempts to suture the laceration normally, led to persistent aqueous leak, and tight suturing was leading to unacceptable distortion of the corneal contour. In the absence of donor tissue or tissue glue, a bulbar conjunctival pedicle flap was used to augment sutures placed without undue tension, and watertight closure of the globe was achieved. Postoperatively, the flap retracted, and excellent tectonic, cosmetic and refractive outcomes were achieved. A conjunctival pedicle flap can be a useful adjunct in the armamentarium of the corneal surgeon while dealing with open globe injuries with corneal tissue loss.