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Biomedical subjects

William W Culbertson

Publications and source records attributed to William W Culbertson.

9 recordsLinked to original sources

Insurgence of Fusarium keratitis associated with contact lens wear.

OBJECTIVE: To describe the clinical presentation and course of patients who developed keratitis due to Fusarium while wearing nontherapeutic soft contact lenses. METHODS: A retrospective review of microbiologic records from January 1, 2004, through April 15, 2006, was performed, identifying all patients with corneal ulceration and a culture positive for Fusarium species. Medical records of 34 patients were reviewed for clinical characteristics, treatment regimens, and microbiologic features. RESULTS: The most common antimicrobial medications administered prior to Fusarium diagnosis were antibacterials in 31 of 34 patients. No distinct preponderance of any one brand of either contact lens or solution was identified. The microbiologic corneal cultures found Fusarium oxysporum in 20 cases, Fusarium solani in 3 cases, Fusarium species not further identifiable in 10 cases, and no growth in 1 case. Patients with a delayed onset of treatment had a tendency for prolonged treatment until cure. CONCLUSIONS: Fusarium has previously been an unusual organism in the etiology of infectious keratitis in the setting of nontherapeutic soft contact lens wear. A delay in proper diagnosis and intervention may contribute to a prolonged treatment course. The microbial spectrum of contact lens-related keratitis may be evolving with higher participation of Fusarium species compared with prior reports.

Adolescent↗

Wound dehiscence after penetrating keratoplasty: clinical characteristics of 51 cases treated at Bascom Palmer Eye Institute.

PURPOSE: To describe the causes, clinical characteristics, and treatment of wound dehiscence in patients after penetrating keratoplasty (PK). METHODS: A retrospective chart review was completed, evaluating patients seen at Bascom Palmer Eye Institute between 1989 and 2001. RESULTS: All dehiscence occurred at the graft-host junction with an average of 5 hours of dehiscence, but no site preference was identified. Dehiscence occurred because of trauma (53%), suture-related complications (27%), infectious keratitis (8%), and spontaneous wound separation (12%). Twelve patients had either intraocular lens dislocation or expulsion; 42 patients underwent primary repair; 7 patients underwent primary PK; and 1 patient underwent primary evisceration. Surgical details were unavailable for 1 patient. Final visual acuity ranged from 20/20 to no light perception. Acuity was unavailable for 2 patients. Visual acuity was 20/200 or better in 23 patients (47%) and less than 20/200 in 26 patients (53%). Two patients (4%) had no light perception. The visual acuity of 13 patients (27%) was 20/40 or better at their last clinic visit. Comparison of predehiscence and postdehiscence visual acuity showed that 23 eyes (54%) had comparable vision after dehiscence, 11 eyes (25%) had improved vision, and 9 eyes (21%) had worsening of vision. CONCLUSIONS: These observations show that graft dehiscence can occur for a variety of reasons after PK, including trauma, infectious keratitis, suture failure, or spontaneous wound separation. The graft-host interface remains vulnerable after corneal transplant and is a potential area for wound dehiscence even many years after keratoplasty. Nevertheless, comparable or even improved vision is possible after wound dehiscence.

Adolescent↗

Corneal flap thickness in laser in situ keratomileusis using the Moria M2 microkeratome.

PURPOSE: To determine the predictability of flap thickness in laser in situ keratomileusis (LASIK) using the Moria M2 microkeratome and identify factors that may be related to variations in flap thickness. SETTING: Laser Vision Correction Center, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA. METHODS: Charts of 208 patients having same-day bilateral LASIK using the Moria M2 microkeratome were reviewed. Intraoperative pachymetry was performed routinely. The right eye was always treated first. The same suction ring, stop, microkeratome head (110 microm or 130 microm), and blade were used in fellow eyes. Subtraction pachymetry was used to calculate flap thickness. Other collected data included age, keratometry, corneal diameter, and preoperative spherical equivalent (SE). RESULTS: With the 110 microm head and slow translation velocity in both eyes, the mean flap thickness was 151.6 microm +/- 24.0 (SD) and 148.5 +/- 24.3 microm in the right and left eyes, respectively. With the 110 microm head and fast translation velocity in both eyes, the mean thickness was 136.2 +/- 25.5 microm and 132.8 +/- 23.5 microm, respectively. With the 130 microm head and fast translation velocity, the mean flap thickness was 145.8 +/- 25.4 microm and 139.9 +/- 25.5 microm, respectively. Flaps were thinner with fast translation velocity, the 110 microm head, and presumably duller blades used in the left eyes. There was a weak but statistically significant inverse correlation between flap thickness and age and between flap thickness and SE. A stronger correlation was found in flap thickness between right and left eyes. CONCLUSIONS: Flap thickness with the Moria M2 microkeratome was variable. Fast translation velocity, a used (presumably duller) blade, and the 110 microm head produced thinner flaps. Given the potential variation in flap thickness (SD 23.5 to 25.5 microm), intraoperative pachymetry might be an adjunctive measure to prevent residual stromal beds that are thinner than planned, especially in patients with high myopia and/or thin corneas.

Adolescent↗

Flap and stromal bed thickness in laser in situ keratomileusis enhancement.

PURPOSE: To evaluate whether flap thickness changes after the primary laser in situ keratomileusis (LASIK) procedure and to assess the accuracy of intraoperative pachymetry and ablation depth measurements in predicting stromal bed thickness before enhancement in eyes that have had primary myopic LASIK. SETTING: Bascom Palmer Eye Institute, Miami, Florida, USA. METHODS: This retrospective noncomparative interventional case series comprised 57 eyes of 42 patients who had LASIK enhancement between June 2001 and September 2002. Exclusion criteria included previous ocular surgery or complications during the first LASIK procedure. Only patients who had had LASIK and enhancement by the same surgeon at our institution and had intraoperative pachymetry readings for both procedures were included. The original flap was relifted in all enhancement procedures. Corneal thickness was routinely measured intraoperatively by ultrasound pachymetry. The age, eye, refraction, date of primary LASIK, central corneal thickness (CCT) and central stromal bed thickness at primary LASIK, depth of ablation, flap thickness (subtraction pachymetry), date of enhancement, CCT and central stromal bed thickness at enhancement, and flap thickness at enhancement were recorded. RESULTS: Thirty-one eyes of 26 patients were myopic and 26 eyes of 16 patients were hyperopic before primary LASIK. The mean time between LASIK and enhancement was 218 days +/- 115 (SD) (193 +/- 88 days in myopic eyes and 248 +/- 136 days in hyperopic eyes [P = .068]). The flap tended to be thicker at enhancement than in the primary LASIK procedure by 9.3 +/- 25.7 microm in myopic eyes (P = .054) and 10.5 +/- 16.6 microm in hyperopic eyes (P = .004). A strong correlation was found between flap thickness in the first and second procedures in myopic and hyperopic eyes (r = 0.6). In myopic eyes, the mean difference between the estimated stromal bed thickness after the first procedure (central bed thickness- ablation depth) and the stromal bed thickness measured directly at enhancement was not statistically significant (3 +/- 29 microm; P = .54, paired t test). A strong correlation was found between the 2 measurements (r = 0.8, P<.001). Another strong correlation was found in myopic eyes between the estimated corneal thickness after the primary LASIK and the corneal thickness measured at enhancement (r = 0.81, P<.001). No correlation was found between the difference in flap thickness and the time to enhancement (r = 0.09 in myopic eyes and r = 0.01 in hyperopic eyes). CONCLUSIONS: Flap thickness tended to be thicker at enhancement than at primary LASIK. Intraoperative pachymetry and ablation depth measurements proved to be precise tools to predict stromal bed thickness before enhancement in eyes that had had primary myopic LASIK. This information may help in planning LASIK enhancements.

Adult↗

Infectious keratitis after LASIK.

PURPOSE: To report the clinical course, management, and outcomes of culture-proven infectious keratitis in 15 eyes of 13 subjects after LASIK. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Fifteen eyes of 13 subjects who underwent LASIK and developed culture-positive keratitis. INTERVENTION: Infectious keratitis was encountered in the operative eyes between 1 day and 450 days. Cultures were obtained, and topical antibiotic therapy was administered in all cases. Some cases required flap lifting, irrigation, and soaking of the bed with antibiotics, flap amputation, or further surgical intervention. MAIN OUTCOME MEASURES: Time periods from onset to diagnosis, from clinical diagnosis to clinical resolution, final acuities, microbiologic profiles, and medical and surgical interventions were reviewed. RESULTS: Onset of symptoms of infection varied, depending on the infectious organism. Bacterial organisms tended to present earlier, whereas mycobacterial and fungal organisms had a later mean onset of presentation. Furthermore, the atypical organisms such as mycobacteria, fungus, and acanthamoeba also had a more delayed diagnosis, resulting in a prolonged disease course. CONCLUSIONS: Infectious keratitis after LASIK is a potentially vision-threatening complication. Onset of symptoms varies depending on causative agents. Furthermore, atypical organisms in the interface or beneath the flap can pose both diagnostic and therapeutic dilemmas. Location in the interface can make it more difficult to culture the organisms and prevent adequate penetration of topical antibiotics.

Adult↗

Endothelial replacement: flap approach.

The concept of selectively transplanting the corneal endothelium has been contemplated since the middle of the twentieth century. Procedures leading up to and including endothelial lamellar keratoplasty are described and discussed in this article.

Endothelium, Corneal↗

Laser in situ keratomileusis for myopia and astigmatism: safety and efficacy: a report by the American Academy of Ophthalmology.

OBJECTIVE: This document describes laser in situ keratomileusis (LASIK) for myopia and astigmatism and examines the evidence to answer key questions about the efficacy and safety of the procedure. METHODS: A literature search conducted for the years 1968 to 2000 retrieved 486 citations and an update search conducted in June 2001 yielded an additional 243 articles. The panel members reviewed 160 of these articles and selected 47 for the panel methodologist to review and rate according to the strength of evidence. A Level I rating is assigned to properly conducted, well-designed, randomized clinical trials; a Level II rating is assigned to well-designed cohort and case-control studies; and a Level III rating is assigned to case series and poorly designed prospective and retrospective studies, including case-control studies. RESULTS: The assessment describes randomized controlled trials published in 1997 or later (Level I evidence) and more recent comparative and noncomparative case series (Level II and Level III evidence), focusing on results for safety and effectiveness. It is difficult to extrapolate results from these studies that are comparable to current practices with the most recent generation lasers because of the rapid evolution of LASIK technology and techniques. It is also difficult to compare studies because of variations in the range of preoperative myopia, follow-up periods, lasers, nomograms, microkeratomes and techniques, the time frame of the study, and the investigators' experience. CONCLUSIONS: For low to moderate myopia, results from studies in the literature have shown that LASIK is effective and predictable in terms of obtaining very good to excellent uncorrected visual acuity and that it is safe in terms of minimal loss of visual acuity. For moderate to high myopia (>6.0 D), the results are more variable, given the wide range of preoperative myopia. The results are similar for treated eyes with mild to moderate degrees of astigmatism (<2.0 D). Serious adverse complications leading to significant permanent visual loss such as infections and corneal ectasia probably occur rarely in LASIK procedures; however, side effects such as dry eyes, night time starbursts, and reduced contrast sensitivity occur relatively frequently. There were insufficient data in prospective, comparative trials to describe the relative advantages and disadvantages of different lasers or nomograms.

Academies and Institutes↗