Faculty Bibliography

This report describes the corneal pathology in an infant with newborn primary congenital glaucoma and discusses whether these findings could be due to a developmental anomaly. The corneal specimen of a 4-month-old infant with newborn primary congenital glaucoma and cloudy corneas who had undergone penetrating keratoplasty was evaluated by light and electron microscopy. Light microscopy showed a thinned epithelium, areas of thickened Bowman's layer (approximately 27 mum thick) interspersed with nuclei, and a thickened and disorganized stroma. Descemet's membrane was intact, and the endothelium was mildly attenuated. The corneal changes seen in this patient may be specific to primary congenital glaucoma and may contribute to the corneal clouding seen so frequently in these patients.

Conjunctival melanoma patients often follow an unpredictable course with significant rates of recurrence and metastases despite optimal treatment. Can we better understand conjunctival melanomas by applying the cancer stem cell hypothesis? The cancer stem cell hypothesis posits that cancers exist as a hierarchical system where cancer stem cells generate and maintain tumors. Targeting cancer stem cells may be the key to future treatments. Directed treatments need to focus on key differences between cancer stem cells and normal tissue stem cells. These directed treatments may lead to curative therapies and decrease the number of recurrences and metastases.

INTRODUCTION/BACKGROUND:Management of corneal scarring following herpes zoster ophthalmicus (HZO) is challenging due to the dense corneal anesthesia that results from viral damage to the subepithelial nerve plexus. These patients have significant risk of graft failure following traditional corneal transplantation. We present a case of a 74-year-old white woman with counting fingers vision from HZO-associated corneal scarring and mature cataract where visual rehabilitation was accomplished with a Type I Boston keratoprosthesis (KPro) and concurrent extracapsular cataract extraction and posterior chamber intraocular lens placement (the "KPro Triple"). One month following surgery, the patient's uncorrected visual acuity improved to 20/25; this level of vision has been maintained for 7 months at present. SURGICAL TECHNIQUE (SEE VIDEO)/UNASSIGNED:The keratoprosthesis is assembled by creating a sandwich composed of the KPro front plate, the donor cornea, and the KPro backplate that is secured with a locking ring. The host cornea is then trephined and posterior synechiae lysed to allow access to the mature cataract. The cataract is manually expressed and a posterior chamber intraocular lens implanted. The assembled keratoprosthesis is then sutured into position with 9.0 nylon. A bandage contact lens is placed. COMMENT/CONCLUSIONS:In patients with severe neurotrophic keratopathy, traditional penetrating keratoplasty is fraught with problems, including poor epithelial healing and corneal ulceration. The Boston KPro can provide rapid visual rehabilitation, despite corneal anaesthesia in these patients, and is currently our treatment of choice as a primary procedure for HZO patients who need corneal transplantation.

PURPOSE/OBJECTIVE:To investigate the differential expression of the glycoprotein clusterin/apoJ (CLU) in normal and Fuchs' endothelial dystrophy (FED) corneal endothelium and to compare the expression of various forms of CLU in normal and FED tissue. METHODS:FED and pseudophakic bullous keratopathy (PBK) corneal buttons were removed during transplantation, and normal corneas were obtained from tissue banks. Human corneal endothelial cells and Descemet's membrane (HCEC-DM) complex was dissected from the stroma. Proteins were separated on 2-D gels and subjected to comparative proteomic analysis. Relative expression of presecretory CLU (pre-sCLU), secretory (s)CLU, and nuclear (n)CLU were compared between normal and FED HCEC-DM by Western blot analysis. Expression of CLU mRNA was compared by using RT-PCR. Subcellular localization of CLU was compared in corneal wholemounts from normal eyes and eyes with FED by immunocytochemistry followed by confocal microscopy. RESULTS:Proteomic analysis revealed an apparent increase in CLU expression in FED HCEC-DM compared with the normal control. Western blot analysis demonstrated that pre-sCLU protein expression was 5.2 times higher in FED than in normal samples (P = 3.52E-05), whereas the mature form modified for secretion (sCLU) was not significantly elevated (P = 0.092). Expression of nCLU protein was significantly elevated in FED (P = 0.013). RT-PCR analysis revealed that CLU mRNA was significantly increased (P = 0.002) in FED samples, but not in PBK samples. CLU also had a distinctive localization in FED samples with enhanced intracellular staining around the guttae and in the nuclei of endothelial cells. CONCLUSIONS:CLU expression is markedly elevated in FED-affected tissue, pointing to a yet undiscovered form of dysregulation of endothelial cell function involved in FED pathogenesis.

PURPOSE/OBJECTIVE:To compare the relative expression of peroxiredoxin (Prx) proteins in normal human corneal endothelium with endothelium in corneas affected by Fuchs' endothelial dystrophy (FED) and between normal human endothelium and epithelial/stromal tissue. METHODS:Human corneal endothelial cell-Descemet's membrane (HCEC-DM) complexes from normal and FED corneal buttons were dissected from the epithelium/stroma. For proteomic analysis, HCEC-DM protein extracts were separated by using two-dimensional gel electrophoresis. Relative differences in protein spot density was analyzed. Proteins of interest, including Prx isoforms, were identified by MALDI-TOF (matrix-assisted desorption ionization-time of flight) mass spectrometry. Western blot analysis compared the relative expression of Prx isoforms in normal and FED endothelium and between normal endothelium and normal epithelium/stroma. Expression of Prx-2 mRNA was compared by using real-time PCR. RESULTS:Proteomic analysis identified differences in the relative expression of Prx isoforms between normal and FED endothelium. Western blot analysis confirmed that expression of Prx-2, -3, and -5 was significantly decreased (P < 0.05) in FED cells. Normal HCECs expressed significantly (P < 0.05) higher levels of Prx-2 and -3 than did the epithelium/stroma. Expression of Prx-5 was not significantly different (P > 0.05) in the endothelium versus the epithelium/stroma. Real-time PCR analysis revealed that Prx-2 mRNA was significantly decreased (P = 0.027) in FED samples. CONCLUSIONS:Prx proteins were identified in human corneal endothelium. The fact that Prx-2 and -3 were expressed at significantly higher levels in HCEC-DM compared with the epithelium/stroma reflects the different physiologic activities of individual corneal cell types. Significantly decreased expression of Prx-2, -3, and -5 in FED may suggest an alteration in the ability of endothelial cells to withstand oxidant-induced damage and may be closely related to the pathogenesis of this disease.

PURPOSE/OBJECTIVE:Ocular Tracking Resistance in U.S. Today (TRUST) annually evaluates in vitro antimicrobial susceptibility of Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae to ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, penicillin, azithromycin, tobramycin, trimethoprim, and polymyxin B in national samples of ocular isolates. DESIGN/METHODS:Laboratory investigation. METHODS:Prospectively collected ocular isolates (197 S. aureus, 49 S. pneumoniae, and 32 H. influenzae) from 35 institutions and archived ocular isolates (760 S. pneumoniae and 356 H. influenzae) from 34 institutions were tested by an independent, central laboratory. Mean minimum inhibitory concentrations that would inhibit growth of 90% of the tested isolates (MIC(90)) were interpreted as susceptible, intermediate, or resistant according to standardized breakpoints for systemic treatment. S. aureus isolates were classified as methicillin susceptible (MSSA) or methicillin resistant (MRSA). RESULTS:MSSA or MRSA susceptibility patterns were virtually identical for the fluoroquinolones, that is, MSSA susceptibility was 79.9% to 81.1% and MRSA susceptibility was 15.2%. Trimethoprim was the only agent tested with high activity against MRSA. All S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin, and moxifloxacin; 89.8% were susceptible to ciprofloxacin. H. influenzae isolates were 100% susceptible to all tested agents but trimethoprim. Ocular TRUST 1 data were consistent with the eight-year longitudinal sample of archived ocular isolates. CONCLUSIONS:The fluoroquinolones were consistently active in MSSA, S. pneumoniae, and H. influenzae. After more than a decade of intensive ciprofloxacin and levofloxacin use as systemic therapy, 100% of ocular S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin, and moxifloxacin; nonsusceptibility to ciprofloxacin was less than 15%. High-level in vitro MRSA resistance suggests the need to consider alternative therapy to fluoroquinolones when MRSA is a likely pathogen.

Conjunctival nevi in children and adolescents often have histologic features that can be difficult to differentiate from malignancy. We have identified a subset of childhood nevi displaying a confluent growth pattern and a lack of maturation that we have defined as juvenile conjunctival nevi (JCN), with the aim of further describing the clinicopathologic features of these lesions. Lesions identified as conjunctival nevus in a tertiary referral hospital were reviewed and the subset of lesions identified as JCN were further evaluated. Clinical details including follow-up data were also gathered. Of the 40 conjunctival nevi identified, 33 fit the criteria for JCN. The mean age at time of excision was 10.9 years (range: 4 to 19 y). Thirty-two lesions were of the compound type; one was a junctional nevus. All showed a nested junctional growth pattern. In 17 lesions (61%), the junctional component extended beyond the subepithelial component (shoulder phenomenon). Maturation was absent in 21 of the compound nevi (66%, average age 10.3 y), and incomplete in the remaining 11 lesions (34%, average age 12.1 y). The nuclei of the subepithelial nevus cells were larger than the epithelial nevus cells in 19 nevi (59%) and the same size in 13 (41%). A lymphocytic host response was present in 17 lesions (52%). Mitotic figures were rarely seen. None of the lesions had recurred over an average follow-up period of 34 months. Recognition of JCN as a distinct morphologic variant of a conjunctival nevus with characteristic histologic features may help to distinguish this benign lesion from melanoma.

PURPOSE/OBJECTIVE:To describe cataract extraction and intraocular lens placement in a patient with an existing Type I Boston keratoprosthesis. METHODS:Case report to describe the surgical technique used to remove a cataract that developed after Boston keratoprosthesis placement. RESULTS:Extracapsular cataract extraction by using an open-sky technique can be used to remove a cataractous lens in the setting of an existing Boston keratoprosthesis. CONCLUSIONS:Although this case shows that it is possible to perform cataract surgery after Boston keratoprosthesis placement, it is prudent to remove the crystalline lens during the initial surgery, even in the absence of a visually significant cataract, because several factors work together to almost guarantee eventual cataract development if the patient is left phakic.

Corneal dystrophies are a group of heterogenous conditions that are characterized by the progressive loss of corneal transparency that results from the accumulation of deposits within the different corneal layers. Up until recently, corneal dystrophies were classified according to their slit lamp appearance, the morphology of the deposits, the depth of the corneal involvement and their histopathological features. This classification has been challenged because of the significant inter-and intra- familial variability in phenotypic expression of the corneal dystrophies and the overlapping characteristics between the different types. In addition, there are dystrophies with atypical characteristics that involve multiple corneal layers or are associated with extraocular involvement that can not be classified into a single type based on morphologic criteria. Recent developments in corneal genetics have shed light on the pathogenesis of corneal dystrophies and have led to the implementation of a new classification scheme that takes into account the responsible gene defect. The discovery that mutations in Tissue Growth factor beta inducible (TGFBI) responsive gene, BIGH3, are the cause of a group of corneal dystrophies (granular, Avellino, lattice and Reis Bucklers) has revolutionized our understanding of these conditions (Stone et al., 1994; Munier et al., 1997). Since this discovery, the genetic basis of many corneal dystrophies and a chromosomal locus for several others has been described. It has also been shown that mutations in the same gene can cause different phenotypes. The association of specific gene mutations with specific phenotypes has given the clinician the opportunity to use molecular genetic analysis to diagnose dystrophic corneal disorders. In parallel, characterization of the mutations responsible for different types of corneal dystrophies has expanded our knowledge regarding their genetic and inheritance patterns. The finding of a highly penetrant, dominantly inherited corneal dystrophy in an affected offspring of unaffected parents has confirmed the existence of spontaneous pathogenic mutations. Additionally, molecular analysis for pathogenetic mutations can confirm the diagnosis in cases with atypical presentations of corneal dystophies. On the other hand, we still know little about how interactions between the environment and the genetic composition affect the phenotype of these conditions. It is highly likely that even when our understanding of the molecular basis of the corneal dystrophies is complete, this knowledge will be used as an adjunct to clinical findings to make the diagnosis of a corneal dystrophy.