Early Endophthalmitis Incidence and Risk Factors after Glaucoma Surgery in the Medicare Population from 2016 to 2019.

PURPOSE: To determine early endophthalmitis incidence and risk factors after glaucoma surgeries in the Medicare population. DESIGN: Retrospective, longitudinal study. PARTICIPANTS: Medicare Fee-for-Service (FFS) and Medicare Advantage beneficiaries in the United States aged 65 years or older undergoing glaucoma surgery. METHODS: Medicare claims were used to identify all patients who underwent glaucoma, cataract, or combined cataract/glaucoma surgery from 2016 to 2019. Endophthalmitis cases within 42 days of the index surgery were identified using the diagnostic codes. Multivariable logistic regression models were used to evaluate factors associated with postoperative endophthalmitis. MAIN OUTCOME MEASURES: The 42-day postoperative endophthalmitis incidence and risk factors associated with endophthalmitis after glaucoma surgery. RESULTS: There were 466 928 glaucoma surgeries, of which 310 823 (66.6%) were combined with cataract surgery. Cataract surgeries alone (n = 8 460 360) served as a reference group. Microinvasive glaucoma surgeries constituted most glaucoma procedures performed (67.8%), followed by trabeculectomy (14.0%), tube shunt (10.9%), and other procedures (7.3%). There were 572 cases of endophthalmitis identified after all glaucoma surgeries. Endophthalmitis incidence after glaucoma, combined cataract/glaucoma, and cataract surgeries alone was 1.5 (95% confidence interval [CI], 1.3-1.7), 1.1 (95% CI, 1.0-1.2), and 0.8 (95% CI, 0.8-0.8) per 1000 procedures, respectively. The median day of diagnosis of endophthalmitis was later for glaucoma surgeries (16.5 days) compared with combined cataract/glaucoma or cataract surgeries alone (8 and 6 days, respectively). Compared with microinvasive glaucoma surgery (MIGS), tube shunts were the only surgery type to be a significant risk factor for endophthalmitis for both stand-alone (adjusted odds ratio [aOR], 1.8, P = 0.002) and combined surgery (aOR 1.8, P = 0.047). The other risk factor for both stand-alone (aOR 1.1, P = 0.001) and combined (aOR 1.06, P = 0.049) surgeries was the Charlson Comorbidity Index (CCI). Age (aOR 1.03, P = 0.004) and male gender (1.46, P = 0.001) were significant risk factors for combined cataract and glaucoma surgeries. CONCLUSIONS: Compared with cataract surgery, early endophthalmitis incidence was higher for both glaucoma and combined cataract/glaucoma surgeries, with the highest incidence among tube shunts. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Cystoid Macular Edema after Cataract Surgery in the United States: IRIS® Registry (Intelligent Research in Sight) Analysis.

PURPOSE: To determine the incidence, risk factors, and visual outcomes of cystoid macular edema (CME) after cataract surgery in the United States. DESIGN: Retrospective, longitudinal, case-control study. PARTICIPANTS: Patients aged ≥ 18 years who underwent phacoemulsification cataract surgery. METHODS: The American Academy of Ophthalmology IRIS® Registry (Intelligent Research in Sight) was used to analyze patients who underwent cataract surgery between 2016 and 2019. Patients who received a diagnosis of CME within 90 days after cataract surgery were classified as cases, and the rest were classified as controls. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for risk factors associated with the development of CME as well as poor visual outcome (defined as a best-recorded visual acuity worse than 20/40 Snellen equivalent at postoperative month 12). MAIN OUTCOME MEASURES: Incidence, demographics, baseline characteristics, and visual outcomes. RESULTS: Of 3.1 million cataract surgeries performed during the study period, CME was diagnosed in 25 595 eyes (0.8%), with an average onset of 6 weeks. Patients with CME were more likely to be male, to be aged < 65 years, to be Black, and to have preexisting diabetic retinopathy. Patients with CME were more likely to have a poor visual outcome (OR, 1.75; 95% CI, 1.66-1.84; P < 0.001), with a mean best-recorded visual acuity of 20/30 at postoperative month 12 (compared with 20/25 for those without CME; P < 0.001). Other factors associated with a poor visual outcome included smoking, Medicaid insurance, non-White race, and baseline ocular comorbidities such as macular degeneration and retinal vein occlusion. CONCLUSIONS: Although the incidence of CME after cataract surgery is low and most eyes achieve a visual acuity of 20/40 or better, there are significant outcome disparities that warrant further exploration. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Endophthalmitis Rates among Medicare Beneficiaries Undergoing Cataract Surgery between 2011 and 2019.

PURPOSE: To determine national incidence and risk factors associated with developing endophthalmitis after cataract surgery in the United States. DESIGN: Retrospective, cross-sectional analysis. PARTICIPANTS: Medicare beneficiaries aged ≥65 years undergoing cataract surgery between 2011 and 2019. METHODS: Medicare claims were used to identify all patients who underwent ≥1 cataract surgery between 2011 and 2019. Endophthalmitis cases within 90 days of the cataract surgery were identified using diagnostic codes. Patients with a history of endophthalmitis 12 months before their cataract surgery procedure were excluded. Annual and aggregate 9-year incidences were determined for all cataract surgeries and for stand-alone cataract procedures. A stepwise multivariable logistic regression model using generalized estimating equations was used to evaluate factors associated with occurrence of postoperative endophthalmitis. MAIN OUTCOME MEASURES: The 90-day postoperative endophthalmitis rate and patient risk factors associated with onset of endophthalmitis after cataract surgery. RESULTS: A total of 14 396 438 cataract surgeries were performed among Medicare beneficiaries between 2011 and 2019. The overall 90-day postoperative endophthalmitis rate was 1.36 per 1000 cataract surgeries for all cataract procedures and 1.30 per 1000 cataract surgeries for stand-alone cataract procedures. A decreasing trend was noted for postoperative endophthalmitis rates during the 9-year study period. On multivariable analysis, the risk of endophthalmitis after cataract surgery was increased for cases performed among those aged ≥75 years versus those aged <75 years (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.11-1.18), Blacks (OR, 1.13; 95% CI, 1.07-1.20), Native Americans (OR, 1.43; 95% CI, 1.19-1.73), and eyes with any history of invasive glaucoma surgery (OR, 1.40; 95% CI, 1.18-1.65). Cataract cases combined with retinal surgery (OR, 2.60; 95% CI, 2.15-3.16) and those performed when the Charlson Comorbidity Index (CCI) was greater than 0 also had an increased likelihood of developing endophthalmitis. The risk of endophthalmitis was lower for cases performed on women versus men (OR, 0.89; 95% CI, 0.86-0.92). CONCLUSIONS: The overall 90-day postoperative endophthalmitis rate after cataract surgery was 1.36 per 1000 cataract surgeries between 2011 and 2019. Patient age, gender, race, and CCI were associated with risk of endophthalmitis.

American Academy of Optometry Microbial Keratitis Think Tank.

SIGNIFICANCE: Think Tank 2019 affirmed that the rate of infection associated with contact lenses has not changed in several decades. Also, there is a trend toward more serious infections associated with Acanthamoeba and fungi. The growing use of contact lenses in children demands our attention with surveillance and case-control studies. PURPOSE: The American Academy of Optometry (AAO) gathered researchers and key opinion leaders from around the world to discuss contact lens-associated microbial keratitis at the 2019 AAO Annual Meeting. METHODS: Experts presented within four sessions. Session 1 covered the epidemiology of microbial keratitis, pathogenesis of Pseudomonas aeruginosa, and the role of lens care systems and storage cases in corneal disease. Session 2 covered nonbacterial forms of keratitis in contact lens wearers. Session 3 covered future needs, challenges, and research questions in relation to microbial keratitis in youth and myopia control, microbiome, antimicrobial surfaces, and genetic susceptibility. Session 4 covered compliance and communication imperatives. RESULTS: The absolute rate of microbial keratitis has remained very consistent for three decades despite new technologies, and extended wear significantly increases the risk. Improved oxygen delivery afforded by silicone hydrogel lenses has not impacted the rates, and although the introduction of daily disposable lenses has minimized the risk of severe disease, there is no consistent evidence that they have altered the overall rate of microbial keratitis. Overnight orthokeratology lenses may increase the risk of microbial keratitis, especially secondary to Acanthamoeba, in children. Compliance remains a concern and a significant risk factor for disease. New insights into host microbiome and genetic susceptibility may uncover new theories. More studies such as case-control designs suited for rare diseases and registries are needed. CONCLUSIONS: The first annual AAO Think Tank acknowledged that the risk of microbial keratitis has not decreased over decades, despite innovation. Important questions and research directions remain.

Prescribing Patterns and Costs Associated with Postoperative Eye Drop Use in Medicare Beneficiaries Undergoing Cataract Surgery.

PURPOSE: To determine costs and prescribing patterns of postoperative eye drops for cataract surgery and estimate potential savings of generic or therapeutic drug substitutions. DESIGN: Retrospective, cross-sectional analysis. PARTICIPANTS: Medicare beneficiaries aged ≥65 years with Part D coverage who underwent cataract surgery in 2016. METHODS: Medicare Part D claims were used to extract information on eye drop prescriptions that were filled during the postoperative period of cataract surgery. Savings from generic or therapeutic drug substitutions were estimated for brand medications. MAIN OUTCOME MEASURES: Total cost of postoperative eye drops for cataract surgery and physician and patient factors associated with medication cost. RESULTS: Postoperative eye drops were prescribed in 2016 to 88% of 591 733 Medicare beneficiaries who underwent cataract surgery during that calendar year, with brand medications accounting for 57.5% of prescription volume. The overall cost totaled more than $167 million, 76.5% of which was attributable to use of brand medications. The mean costs of medications were $228 and $324 for those undergoing 1 and 2 surgeries, respectively. Topical antibiotics (89%) were the most commonly prescribed drug class by volume, followed by topical steroids (86%) and nonsteroidal anti-inflammatory drugs (66%), and accounted for 26%, 37%, and 36% of the total cataract surgery eye drop cost, respectively. Use of therapeutic and generic alternatives could have resulted in cost savings of as much as $118 million, or 70% of the total cost of postoperative eye drops. In adjusted analysis, patient factors associated with increased eye drop cost included older age, female gender, and race or ethnicity. Physician characteristics associated with increased eye drop cost included female gender, greater number of years in practice, practicing in metropolitan versus nonmetropolitan areas, and practicing in the Northeast versus the South and in the South versus the Midwest. CONCLUSIONS: The cost to the Centers for Medicare and Medicaid Services for eye drops prescribed for postoperative use after cataract surgery in 2016 was approximately $170 million. In the absence of evidence of clinical superiority of expensive versus less costly options, substantial opportunity exists to improve the value of care delivered to Medicare beneficiaries.

A Preoperative Medical History and Physical Should Not Be a Requirement for All Cataract Patients.

Cataract surgery poses minimal systemic medical risk, yet a preoperative general medical history and physical is required by the Centers for Medicare and Medicaid Services and other regulatory bodies within 1 month of cataract surgery. Based on prior research and practice guidelines, there is professional consensus that preoperative laboratory testing confers no benefit when routinely performed on cataract surgical patients. Such testing remains commonplace. Although not yet tested in a large-scale trial, there is also no evidence that the required history and physical yields a benefit for most cataract surgical patients above and beyond the screening performed by anesthesia staff on the day of surgery. We propose that the minority of patients who might benefit from a preoperative medical history and physical can be identified prospectively. Regulatory agencies should not constrain medical practice in a way that adds enormous cost and patient burden in the absence of value.

Acanthamoeba Keratitis among Rigid Gas Permeable Contact Lens Wearers in the United States, 2005 through 2011.

PURPOSE: To describe the clinical presentation and outcomes of Acanthamoeba keratitis (AK) in rigid gas permeable (RGP) contact lens wearers and to identify modifiable risk factors. DESIGN: Case-control investigation. PARTICIPANTS: Patients were RGP contact lens-wearing United States residents with a diagnosis of AK from 2005 through 2011. Controls were RGP contact lens wearers with no history of AK who were at least 12 years of age. METHODS: Patients were identified during 2 multistate AK outbreak investigations. Controls from the first investigation in 2007 were identified using a reverse address directory. In the second investigation, controls were recruited from participating ophthalmology and optometry practices. Patients and controls were interviewed by phone using a standardized questionnaire. Odds ratios (ORs) and Fisher exact P values were calculated to assess risk factors associated with infection. MAIN OUTCOME MEASURES: Acanthamoeba keratitis, a rare eye disease primarily affecting contact lens wearers, is caused by free-living amebae, Acanthamoeba species. RESULTS: We identified 37 patients in the 2 investigations, 10 (27%) from the 2007 investigation and 27 (73%) from 2011. There were 17 healthy controls, 9 (53%) from 2007 and 8 (47%) from 2011. Among patients, 9 (24%) wore RGP lenses for orthokeratology or therapeutic indication; no controls wore RGP lenses for these indications. Significant risk factors for AK were wearing lenses for orthokeratology (OR, undefined; P = 0.02), sleeping while wearing lenses (OR, 8.00; P = 0.04), storing lenses in tap water (OR, 16.00; P = 0.001), and topping off contact lens solution in the case (OR, 4.80; P = 0.01). After stratifying by use of RGP lenses for orthokeratology, storing lenses in tap water and topping off remained significant exposures. CONCLUSIONS: Nearly one quarter of patients were orthokeratology wearers. Using tap water to store RGP lenses and topping off solution in the lens case were modifiable risk behaviors identified in RGP wearers who wore lenses for both orthokeratology and nonorthokeratology indications. Rigid gas permeable wearers should avoid exposing their lenses to tap water and should empty their cases and use fresh lens solution each time they take out their lenses.

Characteristics of Endophthalmitis after Cataract Surgery in the United States Medicare Population.

PURPOSE: Endophthalmitis is a rare but sight-threatening infection after cataract surgery. Roughly one third of eyes remain blind after treatment. We report United States population-based data on microbiological investigations and treatment patterns plus risk factors for poor outcomes. DESIGN: Retrospective cohort study. PARTICIPANTS: Medicare beneficiaries from 5 states in whom endophthalmitis developed within 6 weeks after cataract surgery in 2003 and 2004. METHODS: We identified endophthalmitis cases occurring after cataract surgery using Medicare billing claims. We contacted treating physicians and requested they complete a questionnaire on clinical and microbiological data and submit relevant medical records. Two independent observers reviewed materials to confirm that cases met a standardized definition. MAIN OUTCOME MEASURES: Positive culture results, vitrectomy status, microbiology spectrum, and final visual acuity. RESULTS: In total, 615 cases met our case definition. Initial visual acuity was counting fingers or worse for 72%. Among 502 cases with known culture results, 291 (58%) had culture positive results. Twelve percent had positive results for streptococci. More than 99% of cases were treated with intravitreal vancomycin. Vitrectomy was performed in 279 cases (45%), including 201 cases with initial acuity better than light perception. Rates of vitrectomy varied across states, with California having the highest rate and Michigan having the lowest (56% and 19% of cases, respectively). Overall, 43% of individuals achieved visual acuity of 20/40 or better. Poor initial acuity (adjusted odds ratio [OR], 1.08; 95% confidence interval [CI], 1.04-1.12 per 0.10 logarithm of the minimum angle of resolution units), older age at diagnosis (OR, 1.22; 95% CI, 1.03-1.45 per 5-year increase), and more virulent organisms were important predictors of poor final visual acuity. Cases with streptococci infection were 10 times more likely to have poor final acuity than coagulase-negative staphylococci cases (adjusted OR, 11.28; 95% CI, 3.63-35.03). Vitrectomy was not predictive of final visual acuity (adjusted OR, 1.26; 95% CI, 0.78-2.04). CONCLUSIONS: Population-based data on the microbiology of acute postoperative endophthalmitis in the United States after cataract surgery are consistent with prior reports. Vitrectomy usage is higher than that recommended from the Endophthalmitis Vitrectomy Study, with no evidence of increased benefit.

Endophthalmitis rates and risk factors following intraocular surgeries in the medicare population from 2016 to 2019.

AIMS: To determine endophthalmitis rates and risk factors following intraocular surgeries in the Medicare population. METHODS: Retrospective, cross-sectional study from 2016 to 2019 in Medicare fee-for-service and Medicare Advantage beneficiaries. 100% Medicare claims were used to identify eyes that underwent intraocular surgery. Exclusion criteria included eyes that had intraocular surgery 42 days before or after and eyes in patients with a history of endophthalmitis within 12 months. RESULTS: 9 744 400 intraocular surgeries were performed among Medicare beneficiaries from 2016 to 2019. A 42-day postoperative endophthalmitis rate was 0.09%. Endophthalmitis rate by surgery type was 0.43% for corneal transplant, 0.36% for secondary intraocular lens (IOL), 0.24% for retina, 0.16% for glaucoma, 0.11% for cataract combined with other procedures and 0.08% for cataract surgeries alone. On multivariable analysis, the risk of endophthalmitis was increased for all intraocular surgery types when compared with cataract surgeries; adjusted OR (aOR) 5.30 (p<0.01) for corneal transplant, aOR 4.50 (p<0.01) for secondary IOL, aOR 3.00 (p<0.01) for retina, aOR 1.93 (p<0.01) for glaucoma, aOR 1.45 (p<0.01) for combined cataract surgeries. Increased risk of developing endophthalmitis was associated with older age (≥85 vs 65-75 years: aOR 1.36; p<0.01), male sex (aOR 1.20; p<0.001) and greater Charlson Comorbidity Index (≥7 vs 0: aOR 1.79; p<0.01). CONCLUSIONS: Postoperative endophthalmitis rate after intraocular surgeries was 0.09% between 2016 and 2019 for Medicare beneficiaries. Endophthalmitis rates were highest for corneal transplant surgeries followed by secondary IOL surgeries and lowest for cataract surgeries. Older age, male gender and higher comorbidity index were associated with risk of endophthalmitis.

Surgical Approach for Monoclonal Gammopathy of Undetermined Significance-Related Ocular Copper Deposition.

PURPOSE: The aim of this study was to present the surgical management of a patient with ocular copper deposition associated with monoclonal gammopathy of undetermined significance (MGUS). METHODS: This is a case report of a 44-year-old man with MGUS who presented to us with bilateral diffuse deposition of copper in the cornea and lens. RESULTS: Despite initiating systemic therapy for MGUS, no corneal clearing was observed. A decision was made to proceed with cataract extraction in the left eye given worsening vision. Despite trypan blue staining and a central descemetorhexis, visualization remained too poor to complete phacoemulsification. Pars plana lensectomy and vitrectomy to remove the residual lens material and placement of a posterior chamber intraocular lens in the sulcus with endoillumination was subsequently performed. As vision in the left eye steadily improved postoperatively, cataract surgery was then performed in the right eye. With use of trypan blue, creation of a 6-mm central descemetorhexis, and a retinal light pipe for endoillumination anteriorly to augment visualization, capsulorhexis, phacoemulsification, and insertion of intraocular lens in the bag were completed without difficulty. The patient's vision improved at subsequent follow-ups, reaching a final best-corrected visual acuity of 20/20-1 in the right eye and 20/25-1 in the left eye. CONCLUSIONS: Ocular copper deposition is a rare manifestation of MGUS. Cataract extraction is challenging, often requiring advanced techniques. Endoillumination is useful to improve visualization through the dense corneal copper deposition.

Postcataract surgery endophthalmitis in the United States: analysis of the complete 2003 to 2004 Medicare database of cataract surgeries.

OBJECTIVE: To estimate endophthalmitis incidence after cataract surgery nationally and at the state level in 2003 and 2004 and to explore risk factors. DESIGN: Analysis of Medicare beneficiary claims data. PARTICIPANTS: We evaluated billed claims for cataract surgery and endophthalmitis diagnosis and treatment for all Medicare fee-for-service beneficiaries in 2003-2004. METHODS: Cataract surgeries were identified by procedure codes and merged with demographic information. Cataract annual surgical volume was calculated for all surgeons. Presumed postoperative endophthalmitis cases were identified by International Classification of Diseases-9 Clinical Modification Codes on claims within 42 days after surgery. Endophthalmitis rates and 95% confidence intervals (CI) were calculated at state and national levels. Logistic regression was used to investigate the association between developing endophthalmitis and surgery location and surgeon factors. MAIN OUTCOME MEASURES: Endophthalmitis incidence and risk factors. RESULTS: We included 4006 cases of presumed endophthalmitis, which occurred after 3 280 966 cataract surgeries. The national rate in 2003 was 1.33 per 1000 surgeries (95% CI, 1.27-1.38) and decreased to 1.11 per 1000 (95% CI, 1.06-1.16) in 2004. Males (relative risk [RR], 1.23; 95% CI, 1.15-1.31), older individuals (RR, 1.53; 95% CI, 1.38-1.69; ≥85 compared with 65-74 years), blacks (RR, 1.17; 95% CI, 1.03-1.33), and Native Americans (RR, 1.72; 95% CI, 1.07-2.77) had increased risk of disease. After adjustment, surgeries by surgeons with low annual volume (RR, 3.80; 95% CI, 3.13-4.61 for 1-50 compared with ≥1001 annual surgeries) and less experience (RR, 1.41; 95% CI, 1.25-1.59 for 1-10 compared with ≥30 years), and surgeries performed in 2003 (RR, 1.20; 95% CI, 1.13-1.28) had increased endophthalmitis risk. CONCLUSIONS: Endophthalmitis rates are lower than previous yearly US estimates, but remain higher than rates reported from a series of studies from Sweden; patient factors or methodologic differences may contribute to differences across countries. Patient age, gender, and race, and surgeon volume and years of experience are important risk factors.

Lessons learned: wrong intraocular lens.

OBJECTIVE: To report cases involving the placement of the wrong intraocular lens (IOL) at the time of cataract surgery where human error occurred. DESIGN: Retrospective small case series, convenience sample. PARTICIPANTS: Seven surgical cases. METHODS: Institutional review of errors committed and subsequent improvements to clinical protocols. MAIN OUTCOME MEASURES: Lessons learned and changes in procedures adapted. RESULTS: The pathways to a wrong IOL are many but largely reflect some combination of poor surgical team communication, transcription error, lack of preoperative clarity in surgical planning or failure to match the patient, and IOL calculation sheet with 2 unique identifiers. CONCLUSIONS: Safety in surgery involving IOLs is enhanced both by strict procedures, such as an IOL-specific "time-out," and the fostering of a surgical team culture in which all members are encouraged to voice questions and concerns.

Hospital benchmarking: are U.S. eye hospitals ready?

BACKGROUND: Benchmarking is increasingly considered a useful management instrument to improve quality in health care, but little is known about its applicability in hospital settings. PURPOSE: The aims of this study were to assess the applicability of a benchmarking project in U.S. eye hospitals and compare the results with an international initiative. METHODOLOGY: We evaluated multiple cases by applying an evaluation frame abstracted from the literature to five U.S. eye hospitals that used a set of 10 indicators for efficiency benchmarking. Qualitative analysis entailed 46 semistructured face-to-face interviews with stakeholders, document analyses, and questionnaires. FINDINGS: The case studies only partially met the conditions of the evaluation frame. Although learning and quality improvement were stated as overall purposes, the benchmarking initiative was at first focused on efficiency only. No ophthalmic outcomes were included, and clinicians were skeptical about their reporting relevance and disclosure. However, in contrast with earlier findings in international eye hospitals, all U.S. hospitals worked with internal indicators that were integrated in their performance management systems and supported benchmarking. Benchmarking can support performance management in individual hospitals. Having a certain number of comparable institutes provide similar services in a noncompetitive milieu seems to lay fertile ground for benchmarking. International benchmarking is useful only when these conditions are not met nationally. PRACTICE IMPLICATIONS: Although the literature focuses on static conditions for effective benchmarking, our case studies show that it is a highly iterative and learning process. The journey of benchmarking seems to be more important than the destination. Improving patient value (health outcomes per unit of cost) requires, however, an integrative perspective where clinicians and administrators closely cooperate on both quality and efficiency issues. If these worlds do not share such a relationship, the added "public" value of benchmarking in health care is questionable.

Clinical and microbiological characteristics of fungal keratitis in the United States, 2001-2007: a multicenter study.

OBJECTIVE: To study the epidemiology, clinical observations, and microbiologic characteristics of fungal keratitis at tertiary eye care centers in the United States. DESIGN: Retrospective multicenter case series. PARTICIPANTS: Fungal keratitis cases presenting to participating tertiary eye care centers. METHODS: Charts were reviewed for all fungal keratitis cases confirmed by culture, histology, or confocal microscopy between January 1, 2001, and December 31, 2007, at 11 tertiary clinical sites in the United States. MAIN OUTCOME MEASURES: Frequency of potential predisposing factors and associations between these factors and fungal species. RESULTS: A total of 733 cases of fungal keratitis were identified. Most cases were confirmed by culture from corneal scraping (n = 693) or biopsies (n = 19); 16 cases were diagnosed by microscopic examination of corneal scraping alone; and 5 cases were diagnosed by confocal microscopy alone. Some 268 of 733 cases (37%) were associated with refractive contact lens wear, 180 of 733 cases (25%) were associated with ocular trauma, and 209 of 733 cases (29%) were associated with ocular surface disease. No predisposing factor was identified in 76 cases (10%). Filamentous fungi were identified in 141 of 180 ocular trauma cases (78%) and in 231 of 268 refractive contact lens-associated cases (86%). Yeast was the causative organism in 111 of 209 cases (53%) associated with ocular surface disease. Yeast accounted for few cases of fungal keratitis associated with refractive contact-lens wear (20 cases), therapeutic contact-lens wear (11 cases), or ocular trauma (21 cases). Surgical intervention was undertaken in 26% of cases and was most frequently performed for fungal keratitis associated with ocular surface disease (44%). Surgical intervention was more likely in cases associated with filamentous fungi (P = 0.03). Among contact lens wearers, delay in diagnosis of 2 or more weeks increased the likelihood of surgery (age-adjusted odds ratio = 2.2; 95% confidence interval, 1.2-4.2). CONCLUSIONS: Trauma, contact lens wear, and ocular surface disease predispose patients to developing fungal keratitis. Filamentous fungi are most frequently the causative organism for fungal keratitis associated with trauma or contact lens wear, whereas yeast is most frequently the causative organism in patients with ocular surface disease. Delay in diagnosis increases the likelihood of surgical intervention for contact lens-associated fungal keratitis.