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Purpose To compare the efficacy of a single application of lidocaine 2% gel with tetracaine 0.5% drops for topical anesthesia in clear corneal cataract surgery. Setting The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. Methods A preliminary toxicity study applied lidocaine 2% gel in the conjunctival fornices of rabbit eyes (n = 9). Biomicroscopic examination was performed and then enucleation at sequential intervals after the application. Intentional intracameral injection of lidocaine gel was performed (n = 3), followed by enucleation. Histopathological analysis was performed on all eyes. A randomized clinical trial comparing topical anesthesia in clear corneal cataract surgery was performed in 25 eyes of 25 patients (12 eyes randomly assigned to lidocaine gel, 13 eyes to tetracaine drops). Corneal sensation was measured with the Cochet–Bonnet aesthesiometer before application of the topical anesthesia, 5 minutes after application, and at the conclusion of surgery. Additional intraoperative local anesthesia and systemic sedation were recorded. Patients’ subjective level of comfort was reported 20 minutes after surgery, and the surgeon’s perception of patients’ comfort was also noted. Results In rabbits, lidocaine gel did not cause clinical or histopathological alteration of the ocular tissues. In the clinical study, median corneal sensitivity before application, after 5 minutes, and postoperatively was 6, 0, 0 (maximum sensitivity = 6), respectively, in the lidocaine gel group and 5, 0, 0, respectively, in the tetracaine drops group. Additional local anesthesia was administered in 17% and 31% of patients, respectively. Satisfactory comfort was reported by 58% in the lidocaine gel group and 62% in the tetracaine drops group. Conclusions A single application of lidocaine 2% gel was a safe and effective alternative to multiple topical anesthetic drops for clear corneal cataract surgery. Lidocaine 2% gel was similar to tetracaine drops in provision of corneal anesthesia and patient comfort,while causing no significant toxicity to the ocular surface.

The authors have identified a corneal stromal protein (CO-Ag) that may be involved in the pathogenesis of Mooren's ulcer. The CO-Ag cDNA sequence is identical to that of human neutrophil calgranulin C (CaGC). This study sought to demonstrate expression of the CaGC gene in the human cornea and in corneal keratocytes after cytokine stimulation. In situ hybridization and immunohistochemistry were used to localize CaGC mRNA and protein in normal and diseased human corneas, including a specimen with Mooren's ulcer. Cultured bovine keratocytes were stimulated with IL-1 alpha or TNF-alpha, and reverse transcription polymerase chain reaction (RT-PCR) was performed to amplify CaGC cDNA from cytokine-stimulated keratocytes and unstimulated controls. Southern blotting verified the specificity of the RT-PCR amplification products. In situ hybridization detected human CaGC mRNA in the stroma of corneas with Fuchs' dystrophy, postinfection corneas, and a cornea with Mooren's ulcer. In cultured bovine keratocytes, peak levels of CaGC mRNA were reached 6 h after cytokine stimulation. Southern blots with an oligonucleotide probe specific for CaGC detected the RT-PCR products of expected sizes (273 bp) and confirmed that the amplified CO-Ag sequence was identical to that of CaGC. These studies are the first to demonstrate the presence of CaGC in the human cornea and the ability of stromal keratocytes to produce CaGC (CO-Ag). The up-regulation of CaGC gene expression by corneal keratocytes due to proinflammatory cytokines from trauma or inflammation may induce autoimmunity that ultimately results in Mooren's ulceration.

Therapy of ocular fungal infections represents a challenge for the ophthalmic clinician. Although ocular fungal infections are relatively uncommon in developed countries compared with bacterial infections, the need for improved antifungal therapy is emphasized by the potentially poor clinical outcomes in patients with severe ocular mycoses. An increased number of fungal infections of the eye have been reported in the past few decades, in part, because of increased clinical awareness and improved laboratory techniques. The increase reflects more significantly the widespread use of antibiotics, immunosuppression, chemotherapy, and ocular prosthetic devices. Although the number of cases of ocular mycoses have increased, the number of antifungal agents available for therapy are few, given the number of fungal pathogens capable of infecting the eye. Current treatment for systemic fungal infections is not always sufficiently effective for ocular mycoses. The slower research and development progress in antifungal therapy compared with antibacterial therapy stems from the fact that fungal cells, unlike bacteria, are eukaryotic, so any drug that is toxic to fungal cells could potentially exert similar effects on mammalian cells. There also has been less financial incentive for pharmaceutical companies to invest in the development of ocular antifungal agents. Fungal infections can involve various regions of the eye and periocular tissues, including the lacrimal apparatus, conjunctiva, eyelids, and bony orbit. The two most common sites for fungal infections of the eye are the cornea and retina or vitreous. Successful medical treatment of fungal keratitis and endophthalmitis depends not only on the spectrum of antifungal activity of the particular drug but also on the pharmacokinetic properties of the agent (i.e., its ability to achieve therapeutic concentrations in the cornea or vitreous). This article reviews the antifungal agents currently available and under development for use in therapy of ocular fungal infections.

Herpes simplex virus (HSV) eye infections are a major cause of corneal opacity and visual loss in developed countries. The main goals of the treatment of HSV keratitis are: 1To eradicate the live virus 2To promote healing of corneal tissues 3To minimize the scarring resulting from the associated inflammation To decrease the chance for future recurrence The successful management of HSV keratitis depends on clinical recognition of the specific tissue layers involved and the various immune components of the keratitis. Modulation of HSV ocular disease relies upon the appropriate application of antiviral and anti-inflammatory medications.

Varicella-zoster virus (VZV) belongs to the Alphaherpesvirus subfamily along with herpes simplex virus types 1 and 2. The VZV virion consists of a double-stranded DNA core, icosahedral nucleocapsid and a glycoprotein-containing tegument. The tegument is enclosed in a lipid envelope composed of host cell membranes and viral glycoproteins. 2 Only enveloped virions are infectious. Glycoproteins are one of the most important antigens responsible for eliciting both humoral and cell-mediated immunity. Varicella-zoster virus is the causal agent of varicella (chickenpox) and herpes zoster (shingles). The common origin of these two diseases was first suggested in 1892 by Bokay, 119 who reported chickenpox in people exposed to herpes zoster patients, and later confirmed by Kundratitz, 60 who inoculated healthy children with herpes zoster vesicle fluid, causing a chickenpox outbreak. Subsequent studies proved viruses of chickenpox and zoster to be morphologically and histologically identical. 109,124

Parasitic infection of the retina has recently attracted more attention because of an increase in clinical cases occurring in AIDS patients. Recent developments in molecular microbiology have enabled more definitive diagnosis of these retinal parasites in many cases. In this article, a review of the most frequent parasitic infections involving the posterior segment is provided. A summary of retinal parasitic infections and associated systemic diseases is given in Table 1. The suggested therapy of choice is summarized as an outline in Table 2 for quick reference. This review includes a detailed discussion of the different therapeutic strategies and a recent update on medical and surgical methodology.

Efforts to improve the overall quality and efficiency of medical care within limited budgets are ongoing across all medical specialties, including ocular infectious disease. As part of this movement, decision makers are requesting data regarding the value of medical treatments increasingly, in addition to traditional measures of efficacy and safety. The demand for value data within medical care has spurred the growth of outcomes research that is focused on the final end points of treatments, as opposed to intermediate end points, surrogate markers, or the structure and process of providing medical care. Value is a multidimensional concept that requires simultaneous assessment and balancing of many factors affecting the costs and benefits of a treatment. A model illustrating a decision-making structure for conducting multidimensional value assessments for medical interventions has been proposed by Kozma and colleagues. 6 The model includes three types of outcomes of medical care: economic, clinical, and humanistic outcomes (ECHO). Examples of variables within each outcome category are presented below.* *Adapted from Kozma CM, Reeder CE, Schulz RM: Economic, clinical, and humanistic outcomes: A planning model for pharmacoeconomic research. Clin Ther 15:1121–1132, 1993; with permission. Economic Outcomes Direct medical costs Cost of drug Cost of drug administration Cost of treating adverse events Direct nonmedical costs Transporation to clinic Indirect Costs Lost work days Decreased productivity Lost earnings Intangible costs Pain Suffering Clinical Outcomes Efficacy Onset of action Percentage of patients who become pain free Recurrence of symptoms Adverse events Humanistic Outcomes Health-related quality of life Return to normal functioning Satisfaction with therapy Some category examples may be relevant to a significant other or caregiver as well as the patient. The relevance of each type of outcome is dependent chiefly on the clinical characteristics of a disease. For example, the indirect cost of lost work days may be relevant in the treatment of a disease with debilitating symptoms, such as migraine, but have less relevance in a silent, less symptomatic disease, such as hypertension or glaucoma. Chronic diseases with high prevalence and expenditure rates have been first priority for identifying which treatments offer the most value by maintaining or improving quality of care in a cost-efficient manner. Many of these first-priority areas have been addressed to date, and the outcomes movement is now expanding to assess the value of treatments for acute or less prevalent diseases that have several alternative medical treatments available. Given the recent advances in therapies for many diseases of the eye, ophthalmologic treatments should be expected to come under increasing value scrutiny. Glaucoma is an obvious choice, given the number of recently introduced alternative treatments for this chronic disease that effects a growing segment of our population. Perhaps less obvious is the need to assess the comparative value of treatments for ocular infections that are less prevalent and generally of a more acute nature. Over the past few years, however, an increasing array of new, broader spectrum, higher cost treatments (antibacterials, antifungals, and antivirals) have become available, making relative value decisions more important. The purpose of this article is to describe the basic principles of pharmacoeconomic analyses that can be used to enhance the treatment selection process for ocular infections by including a value component.

Purpose To qualitatively assess the endothelial damage on Descemet-stripping automated endothelial keratoplasty (DSAEK) donor tissue resulting from a gentian violet marking pen. Methods An in vitro model was used, by using corneoscleral rims, DSAEK quality corneal donor tissue, and a gentian violet marking pen. After making a mark on the stromal side of a microkeratome-prepared DSAEK corneal button to confirm appropriate orientation of the donor tissue after insertion into the anterior chamber, the corneal tissue was returned to Optisol GS solution for 1 hour. A vital dye assay was used to identify devitalized and necrotic endothelial cells with alizarin red S and trypan blue. Results Corneal donor tissue evaluated with the gentian violet marking pen showed positive trypan blue staining, limited to the area marked with the gentian violet ink. Conclusions Marking the DSAEK donor stromal surface with a gentian violet marker damages the endothelium. Surgeons should limit the size of the mark or use an insertion technique that avoids confusion about orientation of the donor cornea.

Except in animal models of cataractogenesis, the literature on the effects of tea infusion on ocular tissue is scant. In our patient, prolonged exposure to tea infusion may have led to a hypesthetic cornea with secondary limbal stem cell loss. In turn, the eye developed keratinization and corneal neovascularization.

BACKGROUND: Our aim was to examine the change in astigmatism after spherical photorefractive keratectomy (PRK). These effects are essential to optimizing photoastigmatic refractive keratectomy (PARK) to correct astigmatism to within fractions of a diopter. METHODS: We retrospectively reviewed 98 eyes of 178 patients with mild to moderate myopia and cylinder «1.00 diopter (D) treated with spherical PRK (VISX 20/20 STAR excimer laser system); 31 eyes had epithelium removed mechanically with a blade and 67 eyes by a laser-scrape technique. RESULTS: Refractive astigmatism was reduced by greater than 0.25 D in 27 eyes (28%); refractive astigmatism was induced by greater than 0.25 D in 31 eyes (32%); the average vector-corrected difference between an eye's astigmatism before and after surgery was 0.01 ± 0.52 D (P=.85). Eyes with high topographic astigmatism but low refractive cylinder before PRK showed an average of 0.07 ± -0.60 D change in refractive cylinder after PRK. Refractive astigmatism of more than 0.25 D was induced in 16 eyes (44%) that received manual removal of epithelium versus 15 eyes (24%) that received laser removal of epithelium (odds ratio 2.51, P CONCLUSIONS: When using PRK for astigmatism correction, refractive cylinder before surgery rather than topographic astigmatism may be the most appropriate method for targeting the astigmatism correction, especially when the two values are discordant. An unpredictable mild increase or decrease in astigmatism may be expected. [J Refract Surg 1998;14:610-614]

Acanthamoeba keratitis is uncommon, but one of the most severe infectious diseases of the cornea. Delayed diagnosis or misdiagnosis as bacterial or herpes simplex keratitis leads to extensive corneal inflammation and profound visual loss. Therefore, accurate and rapid diagnosis of Acanthamoeba keratitis is essential for successful treatment and good prognosis. We evaluated the usefulness of acridine orange staining from corneal scrapings and contact lens solutions for the rapid diagnosis of four consecutive cases of Acanthamoeba keratitis. Gram stain and culture on nonnutrient agar plates with Escherichia coli overlay were also made. Corneal scrapings stained with acridine orange revealed yellow-to-orange polygonal, cystic structures consistent with the appearance of Acanthamoeba among inflammatory cells and the corneal epithelial cells. The contact lens case solutions of two patients also showed numerous cysts with double wall. Some organisms from the third patient were identified as Acanthamoeba castellani and others as Acanthamoeba lugdunensis. Based on the acridine orange staining results in four cases of Acanthamoeba keratitis, this stain is recommended as a simple and reliable method for the rapid diagnosis of this disease.

Background Air and expansile gases commonly are injected into the eye in both vitreoretinal surgery and anterior segment surgery. Although the halogenated gases are filtered routinely before injection, air often is not prepared in this manner. This study was designed to investigate the effect of filtration on the microbiology of gas mixtures. Methods Two separate studies were conducted, one examining medical grade perfluoropropane gas (C3F8), and the other evaluating air collected from an ophthalmic operating room or emergency room. Aliquots of air or gas were collected through a 0.22-micron filter before and after filtration. The filter discs were cultured for bacterial and fungal organisms. Results Of 514 samples collected, none grew either bacterial or fungal organisms. There was no difference with regard to recovered microbes between filtered and unfiltered air or C3F8, nor was there a difference between operating room air and emergency room air. Positive controls using aerosolized microorganisms yielded heavy growth. Conclusion Based on results obtained in this study and available information on the concentration of airborne microbes, the microbiologic effect of gas filtration is of little significance for volumes routinely injected in ophthalmic surgery.

Purpose The study aimed to determine whether detectable concentrations of colchicine are present in the tear fluid of treated patients with familial Mediterranean fever (FMF) and thus demonstrate a possible route by which colchicine reaches the corneal surface. Methods Tear fluid samples (50-100 microL) were collected from eight FMF patients on long-term colchicine treatment. Colchicine tear fluid concentrations were determined in all patients by radioimmunoassay using goat anticolchicine antibodies and [3H]colchicine (Dupont, Wilmington, DE). Results Detectable concentrations of colchicine, with no apparent effect on the ocular surface, were found in all tear fluid samples (median, 0.46 ng/mL; range, 0.24-1.05 ng/mL). Conclusions This study provides evidence of the route by which colchicine, given systemically, reaches the corneal surface and thus gives credence to the possible inhibitory effect of this drug on corneal wound healing in the cases described in the literature.

Background: Infectious crystalline keratopathy is a distinctive clinical entity characterized by bacterial replication within the cornea without inflammation. The authors report on a patient with infectious crystalline keratopathy due to Streptococcus pneumoniae serotype 11F. They used this isolate to study the contribution of the pneumococcal polysaccharide capsule to the pathogenesis of the infectious crystalline keratopathy. Methods: Aliquots containing 10 6 colony-forming units of pneumococci serotype 11F, serogroup 9 or 15, were inoculated into New Zealand white rabbit corneas. The corneas were examined at 24, 48, and 72 hours. Representative corneas were excised at 24 hours and processed for histopathologic analysis. Results: Pauci-inflammatory crystalline lesions developed in all corneas inoculated with the serotype 11F ocular isolate by 24 hours. Suppurative keratitis developed in control corneas inoculated with serogroup 9 or 15 pneumococci. The nonocular 11F isolates produced lesions with some features compatible with infectious crystalline keratopathy. Conclusion: Different pneumococcal serotypes vary in their ability to produce infectious crystalline keratopathy. Because serotype differences reflect differences in the antigenic polysaccharides of the bacterial capsule, this study suggests that properties of the pneumococcal capsule may influence the initial development of infectious crystalline keratopathy.

Seasonal allergic conjunctivitis (SAC) is an inflammatory response of the conjunctiva triggered by exposure to seasonal allergens. Treatment options for SAC include artificial tears, antihistamines, decongestants, mast cell stabilizers, nonsteroidal anti-inflammatory drugs, dual antihistamine/mast cell stabilizers, immunotherapy and corticosteroids. Topical, intranasal and systemic formulations of corticosteroids have traditionally provided the most effective relief of the inflammation and signs and symptoms associated with severe, acute exacerbations of SAC. However, steroid-induced ocular and systemic side-effects have limited the prescribing of these agents. This limitation of traditional corticosteroids led to the development of modified corticosteroids that retain the anti-inflammatory mechanism of action of traditional corticosteroids with a much-improved safety profile because of their rapid breakdown to inactive metabolites after exerting their activity. The development of one such novel corticosteroid, loteprednol etabonate (LE), led to the insertion of an ester (instead of a ketone) group at the carbon-20 (C-20) position of the basic corticosteroid structure. Clinical trials assessing this C-20 ester corticosteroid have demonstrated similar efficacy to C-20 ketone corticosteroids in the prevention or treatment of the signs and symptoms of SAC but with a greatly improved safety profile, as the C-20 ester corticosteroid is less likely to elevate intraocular pressure. In addition, the ketone at the C-20 position has been implicated in the formation of cataract, while nonketolic corticosteroids do not form Schiff base intermediates with lens proteins, which is a common first step in cataractogenesis. The clinical relevance of the C-20 ester corticosteroid class, as modelled by LE, is that they provide both effective and safe treatment of the inflammation associated with SAC and relief of its signs and symptoms. Loteprednol etabonate offers a well-tolerated treatment option for patients with debilitating acute exacerbations as well as chronic forms of the disease.

This article reviews the complications of laser-assisted in-situ keratomileusis (LASIK) associated with ocular allergy. This review will provide guidance and heighten the need for a more comprehensive allergic evaluation before recommending LASIK procedure to patients. The material provided allows enhanced awareness of the potential postsurgical effects on allergic responses of the ocular surface and management thereof.Ocular allergy is often underdiagnosed and has been previously reported only in a handful of peer-reviewed journals as the cause for ocular irritation and visual morbidity in post-LASIK dry eye disease. Diffuse lamellar keratitis is one complication of LASIK that has been linked to atopic individuals. LASIK causes significant inflammation in normal eyes, which is only exacerbated in atopic patients. Atopy may be a contributing factor in patients with patients with post-LASIK dry eye symptoms. Further investigation is required to better understand the complications of LASIK in allergic patients.LASIK surgery has been associated with increased anterior surface inflammatory processes that include dry eye syndromes and ocular allergy. In addition, poorer outcomes of LASIK procedures have been reported in patients with moderate to severe ocular allergies and chronic forms of allergic conjunctivitis, which is an absolute contraindication to the LASIK procedure. We propose preoperative and postoperative management algorithms for allergic LASIK candidates.

Hyperosmolarity is a central mechanism causing ocular surface inflammation and eye irritation in typical patients suffering from tear dysfunction. Tear composition in dry eyes, or dysfunctional tear syndrome, may destabilize the tear film and cause ocular surface epithelial disease. Increased activity of matrix metalloproteinases (MMPs), especially MMP-9, plays a critical role in wound healing and inflammation and is primarily responsible for the pathologic alterations to the ocular surface that leads to a dysfunctional tear state.Altered corneal epithelial barrier function is the cause for ocular irritation and visual morbidity in dry eye disease. The increased MMP-9 activity in dry eyes may contribute to deranged corneal epithelial barrier function, increased corneal epithelial desquamation, and corneal surface irregularity.Dry eye is one of the most common complications of photorefractive keratectomy and laser in-situ keratomileusis (LASIK). LASIK has both a neurotrophic effect on the cornea and leads to a physical change in corneal shape that results in a change in tear dynamics, leading to ocular surface desiccation. The reduction in tear function after LASIK may induce an increase in osmolarity and consequently raise the concentration of proinflammatory cytokines and MMP-9 in the tear film, which results in dry eyes and insufficient attachment between the corneal flap and the corneal bed. Appropriate diagnosis and management of dysfunctional tear syndrome may lead to less postoperative LASIK complications.

Conjunctivitis is a common problem in primary health care. Inflammation of the conjunctiva may result from infection or noninfectious causes. Microbial conjunctivitis may be caused by bacteria, viruses, or parasites. Although usually a benign, self-limited disease in healthy individuals, serious complications (eg, keratitis) may be sight-threatening. Accurate diagnosis and specific treatment of conjunctivitis remain challenging. History taking and physical examination are occasionally insufficient for correct diagnosis, thus laboratory testing may play a vital role in identification of specific pathogen(s). However, diagnostic testing has several limitations, including time-consuming methods, increased cost, and requirement for expertise in performance and interpretation. Treatment with empirical topical antibiotics for suspected infectious conjunctivitis is controversial. Although antibiotic treatment can diminish risk of adverse events and shorten the course of disease, drug resistance, toxicity, and expense are important considerations in management of acute infectious conjunctivitis.

PURPOSE To report a novel method of preparing planar Descemet stripping automated endothelial keratoplasty (DSAEK) tissue using a femtosecond laser with a hyperopic soft contact lens (Hyp-SCL). METHODS DSAEK tissue was prepared from 11 cadaveric porcine eyes. A femtosecond laser was used to create 400-microm flaps, with or without a Hyp-SCL, after which the eyes were imaged with anterior segment optical coherence tomography. The ratio of the mean central thickness (C) to the mean peripheral thickness (P) was calculated using the flap tool. RESULTS Eleven eyes were cut (5 without, 5 with, and 1 without and with a Hyp-SCL). In all corneas, the cut interfaces were visualized by anterior segment optical coherence tomography. The mean C:P ratio of the flap made without a Hyp-SCL was 0.998 (range 0.968-1.03, SD = 0.254) compared with 0.904 (range 0.851-0.985, SD = 0.509) with a Hyp-SCL (P = 0.001), demonstrating that a cut made with a Hyp-SCL created a flap that was significantly more concave than that created without a Hyp-SCL, resulting in a more planar DSAEK graft. However, the C:P ratios calculated for DSAEK tissue made without (mean 0.998, range 0.965-1.02, SD = 0.0195) and with (mean 1.02, range 0.986-1.05, SD = 0.0250) a Hyp-SCL did not show significance (P = 0.07). CONCLUSIONS Combining a femtosecond laser and a Hyp-SCL may aid in the creation of planar donor tissue for DSAEK. Clinically, this could reduce the amount of postoperative hyperopic shift, although further human corneal studies are warranted.

Purpose To evaluate the long-term results of femtosecond laser-assisted anterior lamellar keratoplasty (FALK) for anterior corneal pathologies. Design Retrospective, noncomparative, interventional case series. Participants Thirteen consecutive patients who underwent FALK for anterior corneal pathologies. Intervention Femtosecond laser-assisted sutureless anterior lamellar keratoplasty. Main Outcome Measures Best spectacle-corrected visual acuity (BSCVA), manifest refraction, need for adjunctive surgery, and complications. Results Follow-up ranged from 12 to 69 months (mean = 31 months). The BSCVA was significantly improved over preoperative values at the 12-, 18-, 24-, and 36-month visits. A BSCVA greater than 20/30 was achieved in 54% of patients at the 12-month visit when all 13 patients were available for follow-up, in 50% and 33% of patients at the 18- and 24-month visits, respectively, when 12 patients were available, and in 60% and 50% of patients at the 36- and 48-month visits when 5 and 2 patients were available, respectively. The BSCVA of the eye that completed the 60- and 70-month visits was 20/50. Patients achieved a mean gain of 5 lines of BSCVA at the 6-, 12-, 18-, and 24-month visits, 4 lines at the 36-month visit, 5 lines at the 48-month visit, and 6 lines at the 60- and 72-month visits. Two patients lost a mean of 1.5 lines of BSCVA because surface haze developed after photorefractive keratectomy (PRK) and granular dystrophy recurred in the graft. At a mean of 5 weeks postoperatively, 83.3% of patients achieved BSCVA within 2 lines of that recorded at the 24-month visit. At the 12-month visit, mean spherical equivalent and refractive astigmatism were −0.4 diopters (D) and 2.2 D, respectively, with no significant shift from preoperative values or values recorded in different follow-up visits. Adjunctive surgeries included phototherapeutic keratectomy, PRK, cataract extraction, and epithelial ingrowth debridement. Complications included residual corneal pathology, mild interface haze, anisometropia, recurrence of pathology, haze after adjunctive PRK, dry eye, epithelial ingrowth, and suspicious ectasia. Conclusions Femtosecond laser-assisted sutureless anterior lamellar keratoplasty improves the BSCVA of patients with anterior corneal pathologies with rapid visual rehabilitation and no significant induced astigmatism. Our preliminary results indicate that FALK results remained stable throughout the follow-up period. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.

BACKGROUND AND OBJECTIVE: To develop a prototype three-dimensional anterior segment spectral-domain optical coherence tomography (SD-OCT) device and demonstrate the feasibility of its use in the operating room. PATIENTS AND METHODS: Single-institution interventional case series including six consecutive patients undergoing Descemet's stripping automated endothelial keratoplasty (DSAEK). The prototype anterior segment SD-OCT was used intraoperatively to search for the presence of interface fluid between the host cornea and the DSAEK graft. RESULTS: Anterior segment SD-OCT was successfully used intraoperatively during DSAEK. After the initial placement of the graft, no fluid was clinically apparent; however, interface fluid was identified by anterior segment SD-OCT in two of the six cases. After additional aspiration, all patients were fluid-free on follow-up anterior segment SD-OCT scanning. CONCLUSION: Intraoperative anterior segment SD-OCT was used successfully to find interface fluid that was clinically undetectable under the microscope. As such, all patients were able to leave the operating room with a fully attached graft. [Ophthalmic Surg Lasers Imaging 2010;41:250–254.]

Objective: Acute conjunctivitis is an extremely common condition and can be associated with significant morbidity and economic burden. Despite this, considerable controversy exists pertaining to the prevalence, diagnosis, management, and treatment of the condition. A panel of ophthalmology experts was assembled to review and discuss the current evidence based literature as it pertains to each of these persistent controversies. Methods and scope: An acute conjunctivitis round table symposium was convened at the American Academy of Ophthalmology meeting in Atlanta, November 2008. The expert panelists consisted of four academic ophthalmologists in the field of cornea and external disease, whose discussion was informed by an English language literature survey carried out on the PubMed database for the period of January 1972 to October 2008. A narrative summary was generated from the literature review and direct transcription of this event, from which this Review article was developed. Findings and conclusions: Considerable light has been shed on acute microbial conjunctivitis and especially those cases caused by adenovirus. Many of the myths that have perpetuated for years have been debunked by emerging evidence. The advent and the implementation of better diagnostic tools and anti-viral medications will help clinicians to improve their diagnostic accuracy, improve management and treatment decisions, and ultimately benefit patients while saving overall healthcare costs.

To assess the kill rates of preserved and preservative-free 8-methoxy fluoroquinolones and benzalkonium chloride (BAC) against isolates of Staphylococcus aureus and coagulase-negative Staphylococcus (CNS) species.Bascom Palmer Eye Institute, Miami, Florida, USA.Ocular and standard isolates of S aureus and CNS were inoculated with saline, 0.005% BAC, gatifloxacin 0.3% containing 0.005% BAC (Zymar), or BAC-free moxifloxacin 0.5% (Vigamox) at 37 degrees C. Bacterial viability was assessed after 15 minutes, 30 minutes, and 60 minutes.Thirteen isolates of S. aureus and 5 isolates of CNS were used. The mean initial load of bacterial inoculum was 5.45 log colony-forming units (CFU)/mL +/- 0.37 (SD). Saline did not affect the density of staphylococci; BAC significantly decreased the staphylococci count to a mean of 3.80 +/- 0.32 log CFU/mL at 60 minutes (P.05). Gatifloxacin 0.3% reduced the number of staphylococci significantly more than moxifloxacin 0.5% at 15 minutes (mean 0.47 +/- 1.12 log CFU/mL versus 4.55 +/- 0.60 log CFU/mL), 30 minutes (mean 0.07 +/- 0.31 log CFU/mL versus 3.82 +/- 1.07 log CFU/mL), and 60 minutes (mean 0.00 +/- 0.00 log CFU/mL versus 2.75 +/- 1.29 log CFU/mL) (P.005). Gatifloxacin 0.3% completely eradicated most S. aureus (10/13) and CNS (3/5) isolates at 15 minutes; moxifloxacin 0.5% did not achieve complete kill in any S. aureus isolate (13/13) or in most CNS isolates (4/5) at 60 minutes.The commercial formulation of gatifloxacin 0.3% containing BAC 0.005% completely eradicated staphylococcal isolates more rapidly than the BAC-free formulation of moxifloxacin 0.5% or BAC 0.005% alone.

Purpose: To report the technique of combining the two different polarization filters to detect the flap edge of the corneoscleral tissue before trephining the Descemet's stripping automated endothelial keratoplasty (DSAEK) tissue. Methods: A human DSAEK donor tissue was prepared with mechanical microkeratome and the tissue on the cutting block was brought under the microscope. The liner, circular, or the combination of these two polarization filters was placed be- tween the tissue and the microscope. The tissue images were taken with digital camera under either of 3 settings. Results: The combination of circular and linear polarization filters enabled us to recognize the edge of the flap more easily than others. Conclusion: This simple system with polarization filters was effective in clear visualization of the flap edge during DSAEK tissue preparation. These features may significantly enhance safety of various surgical procedures, in addition to DSAEK tissue preparation.

Purpose To evaluate surgical outcomes after intraocular lens (IOL) exchange of refractive IOLs in dissatisfied patients. Setting Bascom Palmer Eye Institute, Palm Beach Gardens, Florida, USA. Methods This retrospective case series comprised dissatisfied patients who sought consultation and subsequently had IOL exchange surgery to remove a refractive IOL. Data collected included preoperative subjective and objective findings, surgical technique, and postoperative course. Results Ten patients (12 eyes) had IOL exchange. All patients had subjective visual symptoms before IOL exchange surgery. Despite this, the preoperative corrected distance visual acuity (CDVA) was 20/30 or better in all eyes. During IOL exchange surgery, a monofocal IOL was placed in the capsular bag or the ciliary sulcus. Adjunctive anterior vitrectomy was performed as indicated for vitreous prolapse. The median follow-up after IOL exchange surgery was 8.9 months. Eight patients (10 eyes) were satisfied with the results of the IOL exchange surgery, while 2 patients said their initial symptoms persisted after the exchange. The CDVA was 20/25 or better in 9 eyes at 1 month. The CDVA in the remaining 3 eyes improved to 20/25 or better at 3 months (2 patients) or 6 months (1 patient). One patient had a complicated postoperative course that necessitated repeat IOL exchange with scleral fixation due to inadequate capsule support. Another patient had corneal decompensation after the IOL exchange surgery. Conclusion Results show that IOL exchange is a feasible option for dissatisfied patients with persistent visual symptoms after refractive IOL placement.

An 83-year-old man underwent penetrating keratoplasty for pseudophakic bullous keratopathy in the left eye. Postoperatively, a thin transparent membrane in the anterior chamber was noted. The differential diagnosis included vitreous prolapse, retained capsule, fibrinous anterior chamber membrane, and retained Descemet’s membrane in the anterior chamber, but the diagnosis was uncertain due to corneal edema and Descemet’s membrane folds. Anterior segment optical coherence tomography was used to determine the diagnosis of retained host Descemet’s membrane. This case report demonstrates that anterior segment optical coherence tomography is a useful and noninvasive instrument for diagnosing and following complications from penetrating keratoplasty.

Purpose To test a possible mechanism for allopatric gas-bubble formation in femtosecond laser–assisted surgery using an experimental closed system. Setting Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. Methods Plastic bottles were filled with balanced salt solution (BSS). Femtosecond laser (IntraLase) flap-mode cuts were made on the walls of the BSS bottles. After femtosecond laser application, the BSS bottles were viewed under the excimer laser microscope and the results photographed. Next, the BSS bottles and laser cuts were imaged with optical coherence tomography. Results In-bottle gas bubbles were consistently produced in the closed system. No cut lines crossed the inner wall of the BSS bottles. Conclusion Results show that in situ gas-bubble formation as a mechanism for gas-bubble formation is a possible alternative to gas traveling through the anterior segment and into the intraflap laser space.

Purpose To examine the technique of second-pass femtosecond laser to correct an incomplete flap during laser in situ keratomileusis. Setting Department of Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida, USA. Methods Twenty porcine eyes were assigned to 1 of 4 groups. In the first 2 groups, a flap was created with a femtosecond laser with a centrally black-painted applanator at a 200 μm depth; a second flap was created at a 400 μm depth with the normal applanator. These groups differed by waiting or not waiting for the opaque bubble layer (OBL) to clear. In the third and fourth groups, the eyes were separated into those with and without OBL; however, the same depth was used for the second pass, which was performed after intentional suction loss. After these treatments, the corneas were examined using anterior segment optical coherence tomography (AS-OCT) and the surgical microscope. Results In the first group (did not wait for OBL to clear), the peripheral shallow cut and the central deep line were observed in the AS-OCT images, with corresponding findings under the surgical microscope. In the second group (waited for OBL to disappear), there were 2 parallel lines on the AS-OCT images; the lines corresponded to dual flaps. In the third and fourth same-depth-cut tests, lines and irregularities were seen on the bed and the back of the flap. Conclusion A second femtosecond laser pass for incomplete flaps, especially when the OBL has cleared, may result in an uneven lamellar cut.

Purpose: To describe complications associated with femtosecond laser-assisted flap creation in LASIK surgery. The management and visual outcomes of femtosecond laser complications related to flap creation in LASIK patients are also described. Methods: All eyes that underwent LASIK with the IntraLase femtosecond laser from September 2003 to June 2006 at a university-based refractive center were included in this retrospective, noncomparative, interventional case series and IntraLase-related LASIK complications are described. All flaps were made with the 15- and 30-kHz IntraLase femtosecond laser. Results: Included in the study were 4772 eyes, of which 44 (0.92%) eyes had direct or indirect complications due to flap creation. Thirty-two eyes had indirect complications (diffuse lamellar keratitis [DLK] and transient light sensitivity)—20 (0.42%) eyes developed DLK (stage 1 to 2) and 12 (0.25%) eyes had transient light sensitivity syndrome. Twelve (0.25%) eyes had direct femtosecond laser flap-related complications—8 (0.17%) eyes had premature breakthrough of gas through the epithelium within the flap margins, 3 (0.06%) eyes had incomplete flaps due to suction loss, and 1 (0.02%) eye had irregular flap due to previous corneal scar. Conclusions: Less than 1% of eyes had direct or indirect complications due to femtosecond laser flap creation. Laser in situ keratomileusis complications specifically related to the IntraLase femtosecond laser did not cause loss of best spectacle-corrected visual acuity in any eyes. [ J Refract Surg. 2009;25:979–984.]

Purpose To study the histopathologic features of 19 corneal posterior lamellar grafts in eyes for which Descemet's stripping with automated endothelial keratoplasty (DSAEK) has failed. Design Retrospective case series with clinicopathologic correlation. Participants Nineteen cases of DSAEK failures undergoing repeat DSAEK or penetrating keratoplasty. Methods The histopathologic results of posterior lamellar grafts (also termed DSAEK grafts ), recipient corneas, or both from 19 cases of failed DSAEK were examined. Main Outcome Measures Abnormalities in the DSAEK graft and in the interface between the recipient cornea and the DSAEK graft were assessed. Results Histopathologic features in 19 failed DSAEK grafts revealed attenuation of endothelial cells (16 cases) and presence in the graft–host interface of fibrocellular tissue (11 cases), retained Descemet's membrane (5 cases), epithelial ingrowth (4 cases), or a combination thereof. Four DSAEK grafts had full-thickness corneal layers at 1 edge. Conclusions Presence of interface material, such as fibrocellular tissue, retained Descemet's membrane, and epithelial ingrowth, are potential causes of dislocation. Endothelial attenuation was the most common finding in failed grafts. Decentered DSAEK grafts with full-thickness corneal layers at 1 edge are a potential cause for epithelial ingrowth. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose. To evaluate and compare the in vitro effectiveness of multipurpose contact lens solutions (MPDS) to inhibit fungal colonization of Food and Drug Administration (FDA) contact lens groups. Methods. Contact lenses from FDA groups I (low water content, nonionic), II (high water content, nonionic), III (low water content, ionic), and IV (high water content, ionic) were placed in sterile contact lens cases with 2 mL of ReNu MultiPlus, ReNu with MoistureLoc, or OPTI-FREE RepleniSH. Each contact lens–multipurpose solution combination was challenged with 0.1 mL of 106 colony-forming units/mL of Fusarium oxysporum and incubated at room temperature. Contact lenses and aliquots from phosphate-buffered saline rinse solutions, multipurpose solutions in cases, and lens cases were sampled at 24, 48, and 72 hours, plated on Sabouraud’s agar, incubated at room temperature, and observed for growth (i.e., adhesion) for 1 to 7 days. Results. Used multipurpose contact lens solutions met or exceeded the 1-log reduction requirement of the FDA stand-alone test. Viable fungal colonies were recovered from group II lenses after 24 hours of storage in all three multipurpose solutions. Colonization was also detected with at least one contact lens–multipurpose solution pairing from groups I, III, and IV. Fungi were not recovered from lens–solution combinations after 24 hours or from phosphate-buffered saline solutions or lens cases at any period. Conclusions. Antifungal activity of contaminated multipurpose solutions may be insufficient to prevent fungal colonization of contact lens materials despite meeting or exceeding the FDA stand-alone test criteria. Colonized lens may increase the risk of fungal keratitis.

DSAEK has recently evolved as a preferred method in place of PKP. After DSAEK, we experienced subconjunctival emphysema, decreased air bubble in the AC and low IOP. This could lead to complications, higher rate of dislocation or infection. We should control the wound closure with suture when in doubt.

A surgical technique for implanting a posterior chamber intraocular lens (IOL) in eyes without capsular or zonular support is presented. A 10-0 polypropylene suture attached to a standard needle is tied to the apex of each haptic and passed transclerally through the ciliary sulcus to secure the haptics at the 3 o'clock and 9 o'clock meridians. This technique produced good visual results in six aphakic patients who were contact lens intolerant, two patients in whom capsular or zonular rupture at the time of cataract surgery precluded standard nonsuture fixation techniques, one patient who had intracapsular cataract extraction for a subluxated, cataractous lens, and one patient who had secondary IOL implantation in combination with penetrating keratoplasty for aphakic bullous keratopathy. Advantages over other techniques o£ posterior chamber lens implantation in the absence of capsular support include technical ease, avoidance of iris fixation, and more precise placement of scleral fixation sutures, thus minimizing IOL decentration.

We report the clinical manifestations and outcomes in 4 patients who experienced premature gas-bubble leakage during raster lamellar dissection during IntraLase femtosecond laser corneal flap creation. Three patients experienced a full-thickness epithelial breakthrough and the fourth, a flap tear. The patient who experienced the flap tear was unable to have laser in situ keratomileusis successfully. The flap complications did not result in a decreased best corrected visual acuity in any patient but may have resulted in epithelial ingrowth in one and a corneal scar and microstriae in another. Potential predisposing factors for epithelial breakthrough, the incidence of epithelial breakthrough, and methods for avoiding and salvaging traumatic corneal flaps are discussed.

To compile a survey of complications during and after Descemet's stripping with automated endothelial keratoplasty (DSAEK) in 118 eyes conducted by cornea subspecialists at a single academic center.Retrospective case series.One hundred eighteen eyes undergoing DSAEK in 99 patients.Outcomes of DSAEK performed in 118 eyes by 10 surgeons were reviewed retrospectively. Sixty-four eyes had pseudophakic bullous keratopathy. Forty-one had Fuchs' endothelial dystrophy and cataract. Three had aphakic bullous keratopathy. In 10 eyes, previous DSAEK performed at the same institution failed. Complications of DSAEK were noted from the intraoperative and postoperative periods. Detached DSAEK grafts were repositioned, rebubbled, or both immediately after diagnosis of this complication.Intraoperative and postoperative complications of DSAEK.Graft detachment was the most common type of complication encountered. In 27 (23%) of 118 eyes, graft detachments were observed. Twenty-five eyes with detached grafts successfully were repositioned or rebubbled after surgery, or both. In 1 eye, a previously detached graft reattached spontaneously. In 1 aphakic eye, the graft detached into the vitreous cavity. In 17 eyes, successful reattachment of the cornea occurred (68%). Twenty-one of the 118 eyes were considered to have failed DSAEK, meaning that persistent edema was present after DSAEK. Seven (6%) demonstrated graft rejection. In 5 eyes (4%), retinal detachment (RD) developed. In 6 (5%), cystoid macular edema developed. In 1 aphakic patient, an air bubble could not be maintained during surgery, and sulfur hexafluoride was injected into the anterior chamber. In 1 eye (1%), epithelial ingrowth developed. One eye (1%) demonstrated blood in the graft interface. In 1 eye (1%), a limited intraoperative suprachoroidal hemorrhage occurred. Two eyes (2%) had pupillary block after surgery that resolved with removal of the air bubble.Descemet's stripping with automated endothelial keratoplasty has become a popular and effective treatment for corneal endothelial dysfunction, but complications resulting from DSAEK do occur. Graft detachment is the most common complication, but postoperative repositioning or rebubbling, or both, allow for graft reattachment in most cases. Other complications found in this series were graft failure, graft rejection, cystoid macular edema, RD, suprachoroidal hemorrhage, and pupillary block. Retained Descemet's membrane and epithelial ingrowth, are potential causes of dislocation.

To examine in vitro resistance to azithromycin and moxifloxacin in bacterial conjunctivitis isolates.MIC90s (Minimum Inhibitory Concentration) and resistance rates to azithromycin and moxifloxacin were determined based upon microtiter broth dilution and/or antimicrobial gradient test strips in a multicenter phase III study and confirmed externally.The most common isolates collected from bacterial conjunctivitis patients in the phase III study were Haemophilus influenzae (40.6%), followed by Staphylococcus epidermidis (19.3%), Propionibacterium acnes (17.3%), Streptococcus pneumoniae (16.8%), and Staphylococcus aureus (0.06%). MIC90s for all of these organisms were well below established resistance breakpoints for moxifloxacin, indicating no bacterial resistance. On the other hand, the MIC90 for H. influenzae was 3-fold higher than the resistance breakpoint for azithromycin,or = 128-fold higher for S. epidermidis, 16-fold higher for S. pneumoniae andor = 128-fold higher for S. aureus, indicating moderate to very high bacterial resistance to azithromycin.Resistance to azithromycin is more common than resistance to moxifloxacin in clinical isolates causing bacterial conjunctivitis.

Purpose To report the technique and small case series results of femtosecond laser–assisted sutureless anterior lamellar keratoplasty (FALK) for anterior corneal pathology. Design Retrospective, noncomparative, interventional case series. Participants Twelve consecutive eyes from 12 patients with anterior corneal scarring. Intervention Femtosecond laser–assisted sutureless anterior lamellar keratoplasty. Main Outcome Measures Measured parameters included femtosecond laser settings, technique, uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and complications. Results Mean follow-up was 12.7 months (range, 6–24). No intraoperative complications were found. Uncorrected visual acuity (VA) improved in 7 eyes (58.3%) compared with preoperative VA. The mean difference between preoperative and postoperative UCVAs was a gain of 2.5 lines (range, unchanged–7 lines). Best-corrected VA was unchanged or improved in all eyes compared with preoperative levels. The mean difference between preoperative and postoperative BCVAs was a gain of 3.8 lines (range, unchanged–8 lines). In 2 eyes, adjuvant surgical procedures were performed (one treated with phototherapeutic keratectomy and the other with photorefractive keratectomy). Six patients (50%) developed dry eye after FALK, which improved during the follow-up period. No graft rejection, infection, or epithelial ingrowth was found in this series of patients. Conclusions Femtosecond laser–assisted sutureless anterior lamellar keratoplasty could improve UCVA and BCVA in patients with anterior corneal pathology.

Photorefractive keratectomy (PRK) with mitomycin-C (MMC) was performed in 2 patients with visually significant, complicated laser in situ keratomileusis flap striae. These striae had been resistant to multiple treatments, including stretching, suturing, and PRK. The visual symptoms in both patients resolved after PRK with MMC, and both patients were stable 1 year later. Wavefront-guided PRK with MMC may be a viable treatment for patients who have complicated flap striae resistant to standard measures.

To aid the cataract surgeon's understanding of rational approaches to antimicrobial prophylaxis and place the European Society of Cataract & Refractive Surgeons (ESCRS) postoperative endophthalmitis study in perspective, a review was conducted of published and unpublished data on intracameral antibiotic use during cataract surgery and the antimicrobial efficacy, pharmacodynamics, ocular penetration, and safety of moxifloxacin. The ESCRS-sponsored study of postoperative endophthalmitis prophylaxis reported rates of presumed infectious postoperative endophthalmitis of 0.07% with intracameral cefuroxime treatment and 0.34% in control groups. Postoperative endophthalmitis after cefuroxime use was mostly due to cefuroxime-resistant gram-positive bacteria. Intracameral cefuroxime also requires extemporaneous compounding, has short-term stability, and carries a risk for hypersensitivity. Moxifloxacin, a fourth-generation fluoroquinolone, has potent and rapid bactericidal activity against the most common gram-positive postoperative endophthalmitis pathogens, has excellent ocular penetration after topical administration, and is available in a self-preserved ophthalmic formulation that has been shown safe and effective in preventing endophthalmitis when administered intracamerally in an animal model. Available data suggest that the optimum antibiotic regimen and route of delivery for cataract surgery antimicrobial prophylaxis require further study. Moxifloxacin offers many theoretical advantages that make it an attractive first-line choice for topical use and of interest for intracameral administration.

Human prion diseases are characterized by rapidly progressive fatal neurodegenerative symptoms. In prion diseases, neural tissues have the greatest potential for infectivity, and ocular tissues are included in the category of high infection risk. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have published specific infection control guidelines for prion diseases. Standard Precautions are utilized for all patient care. Additional and more stringent measures are indicated when patients with known or suspected prion disease require ocular surgery. Measures include: notification of infection control, operating room, and decontamination personnel; use of disposable instruments whenever possible; special processing for non-disposable instruments; identification of tissue and laboratory specimens; and incineration or other appropriate treatment of infectious waste. Clumsiness, vision changes, and myoclonus in association with prion disease may predispose patients to traumatic ocular emergencies. Proactively, procedure areas should utilize a multidisciplinary approach to do the following: identify urgent surgical procedures that are likely to be required by these patients; evaluate cleaning procedures that will result in effective tissue removal; identify critical, non-disposable equipment for which there are no disposable alternatives; identify decontamination methods available to the specific facility as well as to identify which recommended decontamination procedures may not be appropriate for ocular instrumentation; and develop precautionary procedures specifically for decontamination of equipment and instruments.

Histamine receptor activation and degranulation of mast cells are the mechanisms by which the ocular itching, hyperemia, chemosis, eyelid swelling, and tearing of seasonal allergic conjunctivitis are induced. Some of the topical solutions available as anti-allergy therapies are intended to interfere with these mechanisms, and the body of research regarding the capabilities of these therapeutic molecules continues to expand.To review the currently available literature regarding one topical ophthalmic anti-allergy agent, olopatadine (Patanol), and its anti-histaminic and mast cell stabilizing actions, both in pre-clinical and clinical settings.Relevant research of laboratory, animal model, and clinical trial studies performed using olopatadine was reviewed. MEDLINE literature searches were conducted and supplemented by additional reports which furthered relevant discussion or were necessary to verify the information resulting from original searches.Olopatadine demonstrates unique properties both pre-clinically and clinically which differentiate it from other therapeutic molecules in its class of dual action mast cell stabilizer/anti-histamine. Its non-perturbation of cell membranes, human conjunctival mast cell stabilization in vivo and in vitro, and superior efficacy as compared to other topical anti-allergic medications including mast cell stabilizers, anti-histamines, and dual action agents, all contribute to olopatadine's profile.Peer-reviewed literature suggests that olopatadine is clinically superior to the other anti-allergic molecules because of its strong anti-histaminic qualities and its unique ocular mast cell stabilizing properties.

A prospective, double-masked, randomized, parallel-group study (n = 25) was conducted to examine the ocular penetration of moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% solution into the aqueous humor following topical administration prior to routine cataract surgery. One drop of antibiotic was instilled every 10 min for four doses beginning 1 h prior to surgery. Preliminary results showed aqueous humor concentrations for moxifloxacin that were significantly greater (p < 0.01) than those for gatifloxacin.

Purpose To measure the achievable perioperative aqueous concentration of the commercially available topically administered fourth generation fluoroquinolones, moxifloxacin 0.5% ophthalmic solution, and gatifloxacin 0.3% ophthalmic solution, and to correlate this concentration with the agents' biological efficacy in the aqueous humor of patients undergoing routine cataract surgery. Design Prospective, randomized, parallel, double-masked, clinical trial. Participants Fifty patients undergoing cataract extraction. Methods Patients (n = 25) were given perioperative topical moxifloxacin 0.5% or topical gatifloxacin 0.3% (n = 25). One drop of antibiotic was administered every 10 minutes for 4 doses beginning 1 hour prior to surgery. Aqueous humor was sampled via paracentesis and antibiotic concentrations were determined using validated high performance liquid chromatography (HPLC) procedures. Dilution analyses were performed to determine the biological efficacy of the agents in the aqueous against Staphylococcus epidermidis , the most common cause of postcataract endophthalmitis. Main Outcome Measures Aqueous humor antibiotic concentrations were measured using HPLC and microdilution bioassay techniques. Biological activity was measured as minimal inhibitory dilution and minimal bactericidal dilution. Results Aqueous humor concentrations for moxifloxacin via HPLC analysis were 1.80 (±1.21) μg/ml, whereas those for gatifloxacin were 0.48 (±0.34) μg/ml. This 3.8-fold difference in aqueous humor antibiotic concentrations was statistically significant ( P = 0.00003). Similarly, the biological dilution analysis of the aqueous humor samples showed that moxifloxacin attained an estimated activity of 2.1 μg/ml, whereas the gatifloxacin activity was approximately 0.4 μg/ml, which represented a 4.9-fold difference. Conclusions This study demonstrated that after topically administered perioperative antibiotics with cataract surgery, moxifloxacin 0.5% ophthalmic solution achieved a statistically significantly higher concentration in aqueous humor compared with gatifloxacin ( P = 0.00003). Results from the broth dilution analysis showed that moxifloxacin 0.5% was biologically more active against S. epidermidis than gatifloxacin 0.3% in aqueous humor after topical application. There were no adverse events reported, and incision wounds healed quickly and as expected.