Faculty Bibliography

OBJECTIVE: To assess the safety of cataract extraction following penetrating keratoplasty for corneal graft survival and to evaluate visual and refractive outcomes in corneal graft patients undergoing cataract extraction. METHODS: Retrospective chart review of 29 eyes of 24 patients with corneal grafts who underwent cataract extraction from January 1, 1993 to December 31, 2002, followed on the Cornea Service at Wills Eye Hospital. RESULTS: The mean time from penetrating keratoplasty to cataract extraction was 8.4 years (range 2 months to 36 years). Following cataract extraction, the corneal grafts remained clear in all but 1 eye (3%), during an average follow-up time of 44.5 months (range 3-118 months). All of the remaining patients benefited from improved visual acuity, with 15 of 28 patients having a postoperative best-corrected visual acuity of 20/30 or better. Patients also benefited from decreased absolute spherical refractive error, with a preoperative mean value of 6.6 +/- 3.4 D compared with 2.4 +/- 1.6 D postoperatively, while cylindrical refractive error remained relatively stable at 3.2 +/- 2.9 D preoperatively and 2.8 +/- 2.4 postoperatively. The patient who developed graft failure had 3 episodes of preoperative endothelial rejection and a clear corneal graft at the time of cataract surgery. CONCLUSIONS: Cataract surgery following penetrating keratoplasty is a safe and effective procedure, with a low but definite risk of corneal graft failure. In patients with clear grafts and visually significant cataracts, cataract extraction alone is preferred over repeat penetrating keratoplasty and cataract extraction

PURPOSE: To further characterize the mutations within the CHST6 gene responsible for causing macular corneal dystrophy in a cohort of affected patients from the United States. DESIGN: Experimental study. METHODS: Genomic DNA was extracted from buccal epithelium of 16 affected patients (14 families), 17 unaffected relatives, and 127 controls, followed by polymerase chain reaction amplification and direct sequencing of the CHST6 coding region. Subtyping of affected patients into type I and II macular corneal dystrophy was performed by measuring antigenic keratan sulfate (AgKS) serum levels. Haplotype analysis was performed in families that demonstrated common mutations. RESULTS: CHST6 coding region analysis in 10 patients identified as having type I macular corneal dystrophy revealed 10 sequence changes: eight missense mutations, four of which are novel (Met104Val, Tyr110Cys, Gln122Pro, and Leu276Pro) and four of which have been reported previously (Ser51Leu, Pro72Ser, Cys102Gly, and Leu200Arg); one novel homozygous nonsense mutation in two patients from a single family (c. 1683C>T, Gln331X); and one frameshift mutation in a heterozygous state in a single patient (c.1744_1751dupGTGCGCTG). Mutation analysis in the four patients identified as having type II macular corneal dystrophy (serum samples were not obtained from two affected patients) revealed three patients heterozygous for either the c.923G>C, c.969C>A, or c.1519T>C sequence changes. The fourth patient was compound heterozygous for c.969C>A and c.1291T>G. None of these changes was observed in 127 control individuals. Haplotype analysis using microsatellite markers flanking the CHST6 gene did not reveal a common founder for the Leu200Arg (1291T>G) missense mutation, present in five families, identifying this position as a mutation hot-spot. CONCLUSIONS: A variety of previously unreported mutations in the coding region of the CHST6 gene are associated with type I macular corneal dystrophy in a cohort of patients from the United States

PURPOSE: To report a series of patients with no previous history of herpes simplex virus (HSV) infection who had new onset of herpetic keratitis after penetrating keratoplasty (PK). DESIGN: Noncontrolled, retrospective case series. METHODS: We included in the study the patients who had new onset of herpetic keratitis after penetrating keratoplasty for corneal diseases unrelated to HSV infection who were seen at the Cornea Service at Wills Eye Hospital (Philadelphia, Pennsylvania) from January 1996 to December 2002. The diagnosis of HSV epithelial keratitis was based on clinical characteristics of either a classic herpetic dendrite, a geographic ulcer, or a nonhealing epithelial defect that responded only to antiviral therapy. RESULTS: Fourteen patients were included in the study. Eight of these (57%) had presented with a geographic ulcer whereas six patients (43%) had a classic dendrite. The most common primary corneal disease that led to PK was pseudophakic bullous keratopathy (36%), followed by keratoconus (29%), Fuchs dystrophy (21%), and corneal scar unrelated to HSV (14%). CONCLUSIONS: The ophthalmologist should be aware of the possibility of herpetic keratitis in eyes after PK, even in patients with no previous history of HSV infection

OBJECTIVE: To review the available evidence for the use of confocal microscopy in diagnosing infectious keratitis and for other applications for ophthalmic practice. METHODS: A MEDLINE search of the peer-reviewed literature for the years 1990 to 2001 yielded 94 citations. The search was limited to studies of human subjects published in English with abstracts. The Ophthalmic Technology Assessment Committee Cornea Panel evaluated these 94 articles for possible clinical relevance and selected 51 (54%) for content review by the panel members. Of these 51 articles, 24 were selected for the panel methodologist to review and rate according to the strength of evidence. RESULTS: Of the 24 articles, 21 (87.5%) were classified as case reports or case series and were rated as level III evidence. Three articles were classified as independent, masked, or objective comparisons performed in a narrow spectrum of patients or in a nonconsecutive series of patients and were rated as level II evidence. No studies were rated as level I evidence, defined as an independent masked comparison of an appropriate spectrum of consecutive patients. CONCLUSION: Confocal microscopy is a new technology with clinical applications in ophthalmology. Although confocal microscopy has been used in other fields of medicine, the optical transparency of the cornea and other structures of the eye provides a unique opportunity to apply this technology. The targeted literature review of 24 articles found no level I studies to support the use of confocal microscopy in the management of eye disorders. Three level II studies pertained to promising clinical applications of the confocal microscope and provided evidence that supports the use of confocal microscopy as an adjunctive modality for diagnosing Acanthamoeba keratitis. The remaining 21 articles, rated as level III evidence, focus on the use of confocal microscopy to facilitate the diagnosis of infectious keratitis, including amoebic and fungal, but currently there are no definitive studies of its role in the differential diagnosis of this condition. There are also level III studies that support the use of the confocal microscope in refractive surgery. Facilitating the diagnosis of infectious keratitis and applying the confocal microscope to refractive surgery may hold the greatest promise of this new technology

PURPOSE: To present the microbial spectrum and susceptibilities of isolates in endophthalmitis following penetrating keratoplasty. DESIGN: Interventional case series. METHODS: The 1,074 consecutive cases of endophthalmitis presenting to Wills Eye Hospital between 1989 and 2000 were reviewed. Fourteen patients with endophthalmitis after penetrating keratoplasty were identified, and vitreous biopsy isolates from these patients were examined. RESULTS: Eleven (78.6%) of 14 vitreous samples were culture-positive, and two others (14.3%) had organisms viewed on pathology specimen, for a total of 13 (92.9%) organism-proven cases of endophthalmitis. Isolates included 10 (76.9%) gram-positive cocci (six Streptococcus sp., three Staphylococcus sp., one identified on pathology specimen only) and three (23.1%) gram-negative organisms (Proteus mirabilis, Serratia marcescens, one identified on pathology specimen only). Susceptibilities to organism-appropriate antibiotic testing are reported, including cefazolin (six of eight, 75.0%), ciprofloxacin (four of seven, 57.1%), nafcillin (four of six, 66.7%), and vancomycin (seven of seven, 100.0%). CONCLUSION: This is the largest series on microbial susceptibilities in postpenetrating keratoplasty endophthalmitis. We report a high percentage of culture-positivity, and a high incidence of gram-positive species, and in particular Streptococcus species, with all tested gram-positive organisms susceptible to vancomycin