Rabbit Fungal Keratitis Model of Fusarium solani Tested Against Three Commercially Available Antifungal Drugs.

OBJECTIVES: The purpose of this study was to develop a reproducible preclinical Fusarium solani keratitis model, which would allow comparative testing of currently available antifungals (NATACYN [Alcon, Fort Worth, TX], voriconazole 1%, and amphotericin B 0.1%) as well as efficacy testing of new antifungals for translation into clinical practice in the future. METHODS: The rabbit F. solani keratitis model was developed in New Zealand white rabbits using local and systemic immunosuppression. Infection was introduced by intrastromal injection of F. solani spores into one of the immunosuppressed rabbit eyes while the contralateral eye was a control. Progress of the infection was assessed by the clinical features, histopathology, and viable fungal counts. In this study, the efficacy of currently available antifungals (NATACYN [Alcon], voriconazole 1%, and amphotericin B 0.1%) was compared. Rabbits were randomly divided (n=4 in each group), and the respective antifungal was instilled topically 5 times/day for 7 days. Treatment effects were analyzed by evaluating the anterior segment with the help of slit-lamp, histopathological findings and viable fungal culture at the end of the experiment. RESULTS: We report the development of a reproducible and progressive rabbit F. solani keratitis model as shown by the substantial viable fungal counts (3 log CFU), the presence of large patchy lesions and substantial hypopyon in the 12-day model correlated with specific histopathological analysis for fungus (extended F. solani hyphae from midcorneal stroma into the anterior chamber and traverse Descemet membrane with anterior chamber suppurative plaque). Voriconazole 1% and NATACYN revealed significant reduction of the fungal wound area (P=0.02 and 0.021), respectively, while amphotericin B 0.1% exhibited P value of 0.083 compared with their infected nontreated controls. Voriconazole 1% and amphotericin B 0.1% showed significant viable fungal count differences (P=0.004 and 0.01), respectively, whereas P value of NATACYN was 0.337 compared with control infected corneas. CONCLUSION: The reported rabbit fungal keratitis model can be used for screening new antifungals and evaluating currently available antifungals to facilitate better clinical outcomes. Voriconazole 1% showed the best efficacy among the three tested currently available antifungals by showing the significant differences in both wound size and viable fungal count comparisons in our F. solani rabbit keratitis model.

Mutations in sodium-borate cotransporter SLC4A11 cause recessive congenital hereditary endothelial dystrophy (CHED2).

Congenital hereditary endothelial dystrophy (CHED) is a heritable, bilateral corneal dystrophy characterized by corneal opacification and nystagmus. We describe seven different mutations in the SLC4A11 gene in ten families with autosomal recessive CHED. Mutations in SLC4A11, which encodes a membrane-bound sodium-borate cotransporter, cause loss of function of the protein either by blocking its membrane targeting or nonsense-mediated decay.

Rapid bactericidal action of alpha-mangostin against MRSA as an outcome of membrane targeting.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has created the need for better therapeutic options. In this study, five natural xanthones were extracted and purified from the fruit hull of Garcinia mangostana and their antimicrobial properties were investigated. α-Mangostin was identified as the most potent among them against Gram-positive pathogens (MIC=0.78-1.56 µg/mL) which included two MRSA isolates. α-Mangostin also exhibited rapid in vitro bactericidal activity (3-log reduction within 5 min). In a multistep (20 passage) resistance selection study using a MRSA isolated from the eye, no resistance against α-mangostin in the strains tested was observed. Biophysical studies using fluorescence probes for membrane potential and permeability, calcein encapsulated large unilamellar vesicles and scanning electron microscopy showed that α-mangostin rapidly disrupted the integrity of the cytoplasmic membrane leading to loss of intracellular components in a concentration-dependent manner. Molecular dynamic simulations revealed that isoprenyl groups were important to reduce the free energy for the burial of the hydrophobic phenyl ring of α-mangostin into the lipid bilayer of the membrane resulting in membrane breakdown and increased permeability. Thus, we suggest that direct interactions of α-mangostin with the bacterial membrane are responsible for the rapid concentration-dependent membrane disruption and bactericidal action.

Nerve growth factor expression and nerve regeneration in monkey corneas after LASIK.

PURPOSE: To determine whether changes in cornea nerve growth factor (NGF) protein and gene expression correlate with corneal nerve regeneration after LASIK in rhesus monkeys. METHODS: Ten rhesus monkeys underwent randomly assigned LASIK procedures to correct -8.0 diopters of myopia in both eyes and two additional monkeys (with no surgery) served as controls. The central corneas of the experimental animals were excised 3 and 7 days and 1, 3, and 6 months after the surgery. Nerve regeneration, NGF mRNA, and protein expression were analyzed by gold chloride staining, real-time polymerase chain reaction, and enzyme-linked immune sorbent assay analysis, respectively. RESULTS: Compared to controls, the LASIK-treated animals had a significantly diminished nerve plexus in the sub-basal region of the cornea at all times after the surgery (P < .001). NGF protein levels decreased significantly on days 3 and 7 after LASIK (P < .001), but returned to control levels 1 month later. NGF mRNA levels increased 5.4-fold on day 3 after the surgery (P < .001), then reduced to two-fold (P < .05) above control levels on day 7 and were back to normal at 3 months and beyond. After LASIK, the changes of early NGF protein and NGF mRNA levels correlated with the density of the corneal nerve plexuses. CONCLUSIONS: The results showed that the LASIK procedure in non-human primates was associated with changes in NGF protein and mRNA levels in the cornea. Such changes may be related to the initiation of nerve regeneration and the final recovery of nerve plexuses in the cornea.

Definition and Diagnostic Criteria for Pediatric Blepharokeratoconjunctivitis.

Importance: Pediatric blepharokeratoconjunctivitis (PBKC) is a chronic, sight-threatening inflammatory ocular surface disease. Due to the lack of unified terminology and diagnostic criteria, nonspecific symptoms and signs, and the challenge of differentiation from similar ocular surface disorders, PBKC may be frequently unrecognized or diagnosed late. Objective: To establish a consensus on the nomenclature, definition, and diagnostic criteria of PBKC. Design, Setting, and Participants: This quality improvement study used expert panel and agreement applying the non-RAND modified Delphi method and open discussions to identify unified nomenclature, definition, and definitive diagnostic criteria for PBKC. The study was conducted between September 1, 2021, and August 14, 2022. Consensus activities were carried out through electronic surveys via email and online virtual meetings. Results: Of 16 expert international panelists (pediatric ophthalmologists or cornea and external diseases specialists) chosen by specific inclusion criteria, including their contribution to scientific leadership and research in PBKC, 14 (87.5%) participated in the consensus. The name proposed was "pediatric blepharokeratoconjunctivitis," and the agreed-on definition was "Pediatric blepharokeratoconjunctivitis is a frequently underdiagnosed, sight-threatening, chronic, and recurrent inflammatory eyelid margin disease associated with ocular surface involvement affecting children and adolescents. Its clinical spectrum includes chronic blepharitis, meibomitis, conjunctivitis, and corneal involvement ranging from superficial punctate keratitis to corneal infiltrates with vascularization and scarring." The diagnostic criteria included 1 or more suggestive symptoms accompanied by clinical signs from 3 anatomical regions: the eyelid margin, conjunctiva, and cornea. For PBKC suspect, the same criteria were included except for corneal involvement. Conclusions and Relevance: The agreements on the name, definition, and proposed diagnostic criteria of PBKC may help ophthalmologists avoid diagnostic confusion and recognize the disease early to establish adequate therapy and avoid sight-threatening complications. The diagnostic criteria rely on published evidence, analysis of simulated clinical cases, and the expert panel's clinical experience, requiring further validation with real patient data analysis.

Corneal transplantation.

Corneal transplantation or keratoplasty has developed rapidly in the past 10 years. Penetrating keratoplasty, a procedure consisting of full-thickness replacement of the cornea, has been the dominant procedure for more than half a century, and successfully caters to most causes of corneal blindness. The adoption by specialist surgeons of newer forms of lamellar transplantation surgery, which selectively replace only diseased layers of the cornea, has been a fundamental change in recent years. Deep anterior lamellar keratoplasty is replacing penetrating keratoplasty for disorders affecting the corneal stromal layers, while eliminating the risk of endothelial rejection. Endothelial keratoplasty, which selectively replaces the corneal endothelium in patients with endothelial disease, has resulted in more rapid and predictable visual outcomes. Other emerging therapies are ocular surface reconstruction and artificial cornea (keratoprosthesis) surgery, which have become more widely available because of rapid advances in these techniques. Collectively, these advances have resulted in improved outcomes, and have expanded the number of cases of corneal blindness, which can now be treated successfully. Femtosecond-laser-assisted surgery, bioengineered corneas, and medical treatment for endothelial disease are also likely to play a part in the future.

A mouse model of corneal endothelial decompensation using cryoinjury.

PURPOSE: To develop a mouse model of bullous keratoplasty and evaluate the safety and efficacy of cryoinjury-induced corneal endothelial decompensation. METHODS: Transcorneal freezing was performed on the right eye of each mouse. One cycle of cryoinjury was performed in 18 eyes (group A), and three cycles were performed in 17 eyes (group B). Pachymetry and intraocular pressure (IOP) measurements were done preoperatively, as well as at 1, 3, 7, 14, and 21 days after cryoinjury. At each post-cryoinjury time point, three mice from each group were euthanized, and the corneas underwent histology and electron microscopy. RESULTS: In both groups, significant corneal edema was noted at post-cryoinjury day 1, which was maintained throughout the study period. IOP remained within normal range in group A, but increased significantly with time in group B (p=0.011 at day 1, 0.038 at day 3, 0.026 at day 14, and 0.008 at day 21). In group B, serious complications including hyphema (one case), severe iridocorneal adhesion (15 cases), and total cataract (three cases) were detected, while only mild iridocorneal adhesion (four cases) and cataract (three cases) were noted in group A. Live/dead cell assay, hematoxylin and eosin staining, and scanning electron microscopy revealed successful ablation of corneal endothelial cells and absence of regeneration in both groups. Hematoxylin and eosin staining and terminal deoxynucleotidyl transferase-mediated nick end labeling assay showed that apoptosis was mainly confined to the posterior stroma and endothelium in group A, while severe apoptosis was observed throughout all layers of the cornea in group B. CONCLUSIONS: One cycle of cryoinjury was safer than three, while both were equally effective in inducing bullous keratopathy. This cryoinjury mouse model of bullous keratopathy was a consistently reproducible model that can be used for further studies on endothelial cell damage and rescue therapy.

In vivo biocompatibility of two PEG/PAA interpenetrating polymer networks as corneal inlays following deep stromal pocket implantation.

This study compared the effects of implanting two interpenetrating polymer networks (IPNs) into rabbit corneas. The first (Implant 1) was based on PEG-diacrylate, the second (Implant 2) was based on PEG-diacrylamide. There were inserted into deep stromal pockets created using a manual surgical technique for either 3 or 6 months. The implanted corneas were compared with normal and sham-operated corneas through slit lamp observation, anterior segment optical coherence tomography, in vivo confocal scanning and histological examination. Corneas with Implant 1 (based on PEG-diacrylate) developed diffuse haze, ulcers and opacities within 3 months, while corneas with Implant 2 (based on PEG-diacrylamide) remained clear at 6 months. They also exhibited normal numbers of epithelial cell layers, without any immune cell infiltration, inflammation, oedema or neovascularisation at post-operative 6 month. Morphological studies showed transient epithelial layer thinning over the hydrogel inserted area and elevated keratocyte activity at 3 months; however, the epithelium thickness and keratocyte morphology were improved at 6 months. Implant 2 exhibited superior in vivo biocompatibility and higher optical clarity than Implant 1. PEG-diacrylamide-based IPN hydrogel is therefore a potential candidate for corneal inlays to correct refractive error.

Indications, outcomes, and risk factors for failure in tectonic keratoplasty.

PURPOSE: Outcomes of corneal transplantation for tectonic indications and risk factors for (tectonic and physiologic) graft failure. DESIGN: Retrospective cohort study. PARTICIPANTS: Consecutive patients who underwent keratoplasty for tectonic indications at the Singapore National Eye Centre (SNEC) between January 1, 1991, and December 1, 2009. METHODS: Clinical data and donor and recipient characteristics were recorded and analyzed from subjects in the prospective Singapore Corneal Transplant Study. MAIN OUTCOME MEASURES: (1) Tectonic (anatomic) failure defined as recurrence of corneal melt threatening tectonic integrity and requiring additional corneal grafting within 3 months of the primary procedure. (2) Physiologic failure defined as irreversible change in graft clarity preventing recovery in useful vision in grafts initially clear 2 weeks postoperatively. RESULTS: The mean age of the study cohort (n = 362, 193 male and 169 female subjects) was 51.5 ± 20.2 years, with a mean follow-up of 25.8 ± 18.7 months. Patients underwent penetrating keratoplasty (PK) (n = 142, 39.2%), anterior lamellar keratoplasty (ALK) (n = 127, 35.1%), or a peripheral corneoscleral patch graft (n = 93, 25.7%) most commonly for inflammation (n = 68, 18.8%), trauma (n = 66, 18.2%), or infection (n = 66, 18.2%). Risk factors for tectonic failure (18/362 eyes, 5.0%) were severe lid disease (odds ratio [OR], 6.1; 95% confidence interval [CI], 1.7-22.1; P = 0.006), central ALK (OR, 7.5; 95% CI, 1.8-32.4; P = 0.007), and peripheral grafts (OR, 5.7; 95% CI, 1.1-28.3; P = 0.035). Among anatomically successful central grafts (n = 223), the mean physiological graft survival was 96 months (95% CI, 83-110); Kaplan-Meier probabilities for survival at 10 years were 66.8% for ALK and 44.2% for PK. Active corneal inflammation (hazard ratio [HR], 2.5; 95% CI, 1.4-4.4; P = 0.003) and larger donor and recipient graft sizes of ≥ 9 mm (HR, 17.9; 95% CI, 2.3-140.3; P = 0.006) were risk factors for physiologic graft failure in anatomically successful eyes with central tectonic grafts. CONCLUSIONS: Patients with lid disease, central ALK, and peripheral grafts were at higher risk of anatomic failure. For anatomically successful cases with central tectonic grafts, active corneal inflammation and donor size ≥ 9 mm were risk factors for physiologic failure. In these cases, our results suggest that ALK had better physiologic graft survival outcomes than PK.

Prevalence of and racial differences in pterygium: a multiethnic population study in Asians.

PURPOSE: To describe the prevalence and risk factors of pterygium in a multiethnic Asian population and to examine racial differences. DESIGN: Population-based study in Singapore, located 1° north of the equator. PARTICIPANTS: Data were analyzed from 8906 participants from 3 population-based studies of Malays, Indians, and Chinese persons 40 years of age and older conducted between 2004 and 2011. METHODS: Standardized slit-lamp examinations were performed by trained study ophthalmologists to examine the anterior segment for evidence of pterygium. Every subject underwent standardized systemic and ocular examinations, interviewer-administered questionnaires, and blood investigations for risk factor assessment. Regression and principle component analysis models were constructed to study the relationship of race and other factors to pterygium. MAIN OUTCOME MEASURES: Any pterygium and severe (grade 3 or opaque) pterygium. RESULTS: The overall prevalence of any pterygium was 10.1% (n = 900), of which severe pterygium was seen in 1.6% (n = 142). The prevalence of any pterygium was more common in Malays (15.5%) than Chinese (7.0%; P<0.001) or Indians (7.0%; P<0.001). Multivariate analysis revealed increasing age (P<0.001), male gender (P<0.001), Malay race (P<0.001), and having a poorer education level (P<0.001) as significant factors for any pterygium. Race contributed significantly to presence of any pterygium (41%; P<0.001) or presence in both eyes (33%; P<0.001) compared with other risk factors. Severe pterygium was associated with outdoor occupation (P = 0.02), but race was not a significant risk factor in multivariate analysis. CONCLUSIONS: This population-based study in Asian persons of different races living in the same geographical location at the equator indicated that race is a significant risk factor for pterygium, with Malays having higher prevalence than Indians and Chinese, while controlling for other risk factors.

S100A expression in normal corneal-limbal epithelial cells and ocular surface squamous cell carcinoma tissue.

PURPOSE: To study the expression and cellular distribution of multiple S100A genes and proteins in normal corneal-limbal epithelium and ocular surface squamous cell carcinoma (SCC) tissue. METHODS: Normal corneal-limbal tissue was obtained from the Lions Eye Bank, Tampa, FL. Ocular surface SCC tissues were excised from patients undergoing surgery at Singapore National Eye Centre. S100A mRNA expression was measured by quantitative PCR. S100 protein distribution was determined by immunofluorescent staining analysis. RESULTS: Twelve S100 mRNAs were identified in human corneal and limbal epithelial cells. S100A2, A6, A8, A9, A10, and A11 mRNA was expressed at high level, while S100A1, A3, A4, A5, A6, A7, and A12 mRNA expression was low. The intracellular localization of S100A2, A6, A8, A9, A10 and A11 protein was determined in normal corneal-limbal and SCC tissues. S100A2 and S100A10 proteins were enriched in basal limbal epithelial cells of the normal tissue. S100A8 and S100A9 were found only at the surface of peripheral corneal and limbal epithelium. S100A6 was uniformly found at the plasma membrane of corneal and limbal epithelial cells. S100A11 was found at the supralayer limbal epithelial cells adjacent to the conjunctiva. SCC tissue showed typical pathological changes with expression of cytokeartin (CK) 14 and CK4 in the epithelial cells. All SCC epithelial cells were positive of S100A2, S100A10, S100A6 and S100A11 staining. Intracellular staining of S100A8 and S100A9 was found in several layers of SCC epithelium. Expression of S100A2 and S100A10 decreased dramatically in cultured limbal epithelial cells with increased passaging, which was accompanied by a small increase of S100A9 mRNA, with no changes of S100A8 gene expression. Serum and growth hormone depletion of the culture serum caused a small reduction of S100A2 and S100A10 gene expression, which was accompanied by a small increase of S100A9 mRNA while no changes of S100A8 expression was measured. CONCLUSIONS: Normal corneal and limbal epithelial cells express a broad spectrum of S100 genes and proteins. Ocular surface SCC express high levels of S100A2, S100A10, S100A8 and S100A9 proteins. The expression of S100A2 and S100A10 is associated with limbal epithelial cell proliferation and differentiation.

Incidence and characteristics of unilateral keratoconus classified on corneal topography.

PURPOSE: To evaluate the characteristics of unilateral keratoconus defined on the basis of corneal topography and analyze videokeratography parameters between fellow eyes and normal controls. METHODS: A total of 111 patients with clinical keratoconus were prospectively enrolled. Both eyes were evaluated with Tomey (Tomey Corp) and Orbscan II (Bausch & Lomb) corneal topography systems. The patient was classified as having unilateral keratoconus if one eye had clinical keratoconus and the other eye did not have any topographic signs of keratoconus such as asymmetric videokeratographic pattern, positive result in Tomey keratoconus screening, maximum posterior elevation >40 µm, or corneal thinnest pachymetry <500 µm. Clinical characteristics and 13 Orbscan II quantitative indices between keratoconic and fellow eyes and normal control eyes were evaluated. RESULTS: Five (4.5%) of 111 patients with keratoconus had no topographic evidence of keratoconus in the fellow eye. All clinically normal fellow eyes had symmetric bowtie patterns. Statistically significant differences were noted in maximum posterior elevation, corneal irregularity, and corneal thinnest values between keratoconic eyes and fellow eyes, and between keratoconic eyes and control eyes. Only 3-mm irregularity was significantly higher in the fellow eyes compared with control eyes (P<.05). An increased trend for corneal 5-mm irregularity was found in fellow eyes compared to control eyes. CONCLUSIONS: The incidence of unilateral keratoconus was 4.5%. A trend of higher irregularity was found in fellow eyes compared with control eyes. This finding indicates that fellow eyes may show a certain low-expressivity morphologic feature of keratoconus.

A survey of contact lens complications in Singapore.

OBJECTIVES: To describe the type of complications related to contact lens wear seen in a hospital setting in Singapore. METHODS: Data were collated over a 2-year period from April 1999 to March 2001, from all public hospitals in Singapore. A standardized clinical record form was completed by the attending doctor when a patient presented for contact lens-related complications. RESULTS: Nine hundred and fifty-three contact lens-related complications were recorded. The mean age of presentation was 26.4 years. Women made up the majority n=491 (68%). Most patients were Chinese (555, 77%). Six hundred and seventy-six (93.7%) patients were soft contact lens wearers. Most patients, 585 patients (85.2%) wore their lenses on a daily basis. Two hundred and forty-four cases (25.6%) of infective keratitis were seen, with 55 patients requiring hospital admission for management of the infection. Soft disposable contact lens wear was associated with the majority of the infective keratitis (178, 73%). Epithelial keratitis occurred in 229 patients (24.0%) with punctuate epithelial erosions being the commonest presentation in 139 (14.6%). Allergic conjunctivitis occurred in 179 (18.8%) of the cases with giant papillary conjunctivitis accounting for 147 (15.4%) of them. Dry eyes (77, 8.1%), sterile infiltrates (71, 7.5%) and neovascularization of the cornea (75, 7.9%) were the next commonest complications seen. Corneal edema, solution- and lens-related complications occurred in small numbers, accounting for less than 5% of the complications reported. CONCLUSION: Infective keratitis secondary to soft lens wear was the most common complication, followed by epithelial keratitis and allergic conjunctivitis seen in public hospitals in Singapore.

IMI Prevention of Myopia and Its Progression.

The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high myopia-associated optic neuropathy, are now some of the most common causes of irreversible blindness. Hence, strategies are warranted to reduce the prevalence of myopia and the progression to high myopia because this is the main modifiable risk factor for pathologic myopia. On the basis of published population-based and interventional studies, an important strategy to reduce the development of myopia is encouraging schoolchildren to spend more time outdoors. As compared with other measures, spending more time outdoors is the safest strategy and aligns with other existing health initiatives, such as obesity prevention, by promoting a healthier lifestyle for children and adolescents. Useful clinical measures to reduce or slow the progression of myopia include the daily application of low-dose atropine eye drops, in concentrations ranging between 0.01% and 0.05%, despite the side effects of a slightly reduced amplitude of accommodation, slight mydriasis, and risk of an allergic reaction; multifocal spectacle design; contact lenses that have power profiles that produce peripheral myopic defocus; and orthokeratology using corneal gas-permeable contact lenses that are designed to flatten the central cornea, leading to midperipheral steeping and peripheral myopic defocus, during overnight wear to eliminate daytime myopia. The risk-to-benefit ratio needs to be weighed up for the individual on the basis of their age, health, and lifestyle. The measures listed above are not mutually exclusive and are beginning to be examined in combination.

SLC4A11 mutations in Fuchs endothelial corneal dystrophy.

The endothelial (posterior) corneal dystrophies, which result from primary endothelial dysfunction, include Fuchs endothelial corneal dystrophy (FECD), posterior polymorphous corneal dystrophy (PPCD) and congenital hereditary endothelial dystrophy (CHED). Mutations in SLC4A11 gene have been recently identified in patients with recessive CHED (CHED2). In this study, we show that heterozygous mutations in the SLC4A11 gene also cause late-onset FECD. Four heterozygous mutations [three missense mutations (E399K, G709E and T754M) and one deletion mutation (c.99-100delTC)] absent in ethnically matched controls were identified in a screen of 89 FECD patients. Missense mutations involved amino acid residues showing high interspecies conservation, indicating that mutations at these sites would be deleterious. Accordingly, immunoblot analysis, biochemical assay of cell surface localization and confocal immunolocalization showed that missense proteins encoded by the mutants were defective in localization to the cell surface. Our data suggests that SLC4A11 haploinsufficiency and gradual accumulation of the aberrant misfolded protein may play a role in FECD pathology and that reduced levels of SLC4A11 influence the long-term viability of the neural crest derived corneal endothelial cells.

Effect of intracameral injection of fibrin tissue sealant on the rabbit anterior segment.

PURPOSE: To investigate the effect of intracameral injection of fibrin tissue sealant on the anterior segment structures in a rabbit model. METHODS: One eye of 10 rabbits received an intracameral injection of fibrin tissue sealant with a thrombin concentration of 500 IU (TISSEEL), and the fellow eye received an intracameral injection of balanced salt solution as a control. The rabbits were followed up with serial slit-lamp examinations, photography, high resolution anterior segment optical coherence tomography scans with pachymetry measurement, and intraocular pressure (IOP) monitoring until complete dissolution of the fibrin sealant. Corneal endothelial cell viability was evaluated using live/dead cell assays. Apoptosis of the cornea and trabecular meshwork were evaluated using TUNEL assays. Ultra-structural examinations of the cornea and trabecular meshwork were performed using electron microscopy. Histology of the trabecular meshwork and iris were analyzed using light microscopy. RESULTS: The quantity of the intracameral fibrin sealant was shown to be significantly correlated with increased IOP and pachymetry post-operatively. Complete dissolution of the fibrin sealant occurred between 15 and 30 days. Live/dead cell assays showed no decrease in viability of the corneal endothelium, and TUNEL assays showed no increase in apoptosis of the corneal epithelium, stroma, endothelium, or trabecular meshwork in the eyes with the fibrin sealant. Light and electron microscopy of the anterior segment structures were unremarkable. CONCLUSION: The intracameral use of fibrin glue was associated with a transient increase in IOP and pachymetry. However, there was no evidence of toxicity or structural damage to the corneal endothelium, trabecular meshwork, or iris.

Dietary factors, myopia, and axial dimensions in children.

PURPOSE: To evaluate the possible associations between dietary factors and myopia. DESIGN: Cross-sectional study. PARTICIPANTS: Eight hundred fifty-one Chinese schoolchildren from the Singapore Cohort Study of Risk Factors for Myopia. METHODS: Diet was assessed using a semiquantitative food-frequency questionnaire. Spherical equivalent (SE) refraction was assessed with an autorefractometer, and axial length (AL) by contact ultrasound A-scan biometry. MAIN OUTCOME MEASURES: Myopia was defined as SE< or =-0.5 diopters (D). Spherical equivalent and AL were analyzed by quartile groups. RESULTS: The mean age (+/-standard deviation) was 12.81+/-0.83 years, approximately half were male (422 children [49.6%]), and 653 (73.8%) children had myopia. In multivariate models, AL was longest in the highest quartile group of total cholesterol intake compared with the lowest (adjusted mean [95% confidence interval], 24.66 [24.62-24.71] mm vs. 24.32 [24.27-24.36] mm; P = 0.026, for trend) and was longest in the highest quartile group of saturated fat intake compared with the lowest (24.65 [24.60-24.70] vs. 24.36 [24.32-24.41] mm; P = 0.039, for trend). None of the nutrients was associated with SE or a diagnosis of myopia. CONCLUSIONS: Higher saturated fat and cholesterol intake are associated with longer AL in otherwise healthy Singapore Chinese schoolchildren.

Anterior lamellar keratoplasty: 'Back to the Future'- a review.

Newer forms of lamellar keratoplasty techniques have emerged in the last decade or so revolving around the concept of targeted replacement of diseased corneal layers. These include anterior lamellar keratoplasty (ALK) techniques that aim to selectively replace diseased corneal stroma and, endothelial keratoplasty techniques aiming to replaced damaged endothelium in endothelial disorders. ALK surgery has a distinct advantage over penetrating keratoplasty (PK) in that it minimizes unnecessary replacement of the unaffected healthy endothelial layer thereby almost eliminating the risk of endothelial rejection, a major cause of graft failure in PK. Overall it provides increased life expectancy to the graft and with advancements in the surgical technique and instrumentation for ALK, the visual outcomes are now comparable if not better to standard PK. There are several forms of ALK procedures that have evolved to cater to a wide range of stromal disorders. This article reviews the various emerging techniques of anterior lamellar surgery, its indications and visual outcomes, to emphasize the shift from PK to ALK for stromal disorders with a healthy endothelium.

Cytomegalovirus endotheliitis in Descemet's stripping endothelial keratoplasty.

OBJECTIVE: To report 4 cases of undiagnosed cytomegalovirus (CMV) endotheliitis in patients who underwent Descemet's stripping automated endothelial keratoplasty (DSAEK). DESIGN: Retrospective interventional case series. PARTICIPANTS: Four eyes of 4 patients diagnosed with active CMV endotheliitis after DSAEK. METHODS: Retrospective review of the medical records of 4 patients with DSAEK who had an aqueous tap that was positive for CMV DNA but negative for herpes simplex virus (HSV) and varicella zoster virus. MAIN OUTCOME MEASURE: Clinical features and management. RESULTS: Four immunocompetent Chinese male patients with a mean age of 67 years underwent DSAEK for posterior polymorphous dystrophy (1), Fuchs' heterochromic cyclitis (1), pseudophakic bullous keratopathy (1), and herpetic keratouveitis (1). Clinical findings seen in all patients were localized corneal edema, increased intraocular pressure, pigmented keratic precipitates (KPs), and no/minimal anterior chamber (AC) activity. An unexplained sudden decrease in endothelial cell count (ECC) in the absence of rejection or significant inflammation was seen in 3 patients, whereas 1 patient also developed concomitant retinitis. CMV DNA was positive in all aqueous specimens and from the vitreous of the patient with retinitis. All patients were treated with oral valganciclovir with resolution of inflammation; 2 patients had recurrences; 1 patient developed recurrent retinitis; and 1 patient developed recurrent CMV endotheliitis and is currently receiving maintenance therapy with oral valganciclovir. CONCLUSIONS: CMV endotheliitis with corneal edema masqueraded as a variety of other endothelial conditions, which resulted in DSAEK surgery being performed in these patients who may have responded to antiviral treatment without the need for endothelial transplantation. A heightened awareness is required to exclude CMV endotheliitis as the cause for endothelial decompensation or unexplained, sudden reduction in ECCs post-DSAEK in the absence of other complications, and it should be differentiated from allograft rejection in view of the critical difference in treatment.

Outcomes of therapeutic deep lamellar keratoplasty and penetrating keratoplasty for advanced infectious keratitis: a comparative study.

PURPOSE: To compare the therapeutic success, visual outcomes, complications, and graft survival rates of therapeutic deep anterior lamellar keratoplasty (TDALK) and therapeutic penetrating keratoplasty (TPK) for advanced infectious keratitis. DESIGN: Retrospective, comparative study. PARTICIPANTS: One hundred twenty-three patients (126 eyes) with medically uncontrolled infectious keratitis of bacterial, fungal, or acanthamoeba etiologies who underwent TDALK (n = 26) or TPK (n = 100 eyes; 80 nonperforated ulcers; 20 perforated ulcers; mean follow-up in TDALK, 12.9 months; in TPK, 21.3 months). METHODS: We performed TDALK for infections confined to the corneal stroma and the technique used was either manual lamellar dissection or Anwar's big bubble technique for total stromal removal. Therapeutic penetrating keratoplasty was performed for either nonperforated or perforated ulcers. Comparison with respect to recurrence of infection, visual acuity, graft survival, and complications was made. Baseline characteristics of the patients were analyzed using the chi-square test. Kaplan-Meier survival analysis was used to evaluate graft survival. MAIN OUTCOMES MEASURES: Therapeutic success (eradication of infection) or therapeutic failure (recurrence of original infection in cornea or sclera, or as endophthalmitis), graft survival (clarity), and best-corrected visual acuity (BCVA). RESULTS: Therapeutic success rate of 84.6% was achieved in the TDALK group and 88% in the TPK group (P = 0.74); of the 12 eyes with recurrence of infection in the TPK cohort, 6 developed endophthalmitis with poor outcomes. A BCVA of > or =6/9 was achieved in 50% of patients in the TDALK group and 20.2% in the TPK group (P = 0.01). Mean improvement of acuity was 7.27 lines in the TDALK group and 4.76 lines in the TPK group (P = 0.01). Kaplan-Meier survival analysis at 1 year showed better graft survival for TDALK (90%) compared with TPK (78.4%). CONCLUSIONS: For medically unresponsive infectious keratitis, TDALK may be considered instead of TPK yielding similar graft survival, without an increased risk of disease recurrence.