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Biomedical subjects

Terrence P O'Brien

Publications and source records attributed to Terrence P O'Brien.

36 records · Page 2Linked to original sources
PubMed2004

A randomized trial of topical cyclosporin 0.05% in topical steroid-resistant atopic keratoconjunctivitis.

OBJECTIVE: To evaluate the short-term efficacy and safety of topical cyclosporin A 0.05% in the treatment of patients with severe, steroid-resistant atopic keratoconjunctivitis (AKC). DESIGN: Multicenter, placebo-controlled, double-masked, randomized trial. PARTICIPANTS: Twenty-two patients with AKC refractory to topical steroid treatment. INTERVENTION: Patients were randomly assigned (1:1) to treatment with topical 0.05% cyclosporin A eyedrops or a placebo (artificial tears) for a period of 28 days, 6 times daily during the first 2 weeks and 4 times daily during the last 2 weeks. MAIN OUTCOME MEASURES: Symptoms (itching, tearing, discomfort, mucous discharge, and photophobia) and signs (bulbar conjunctival hyperemia, upper tarsal conjunctival papillae, punctate keratitis, corneal neovascularization, cicatrizing conjunctivitis, and blepharitis) of AKC recorded on the day of enrollment and at the end of the treatment period. RESULTS: A composite score computed by summing the severity grade over all 5 symptoms and 6 signs of AKC for each patient indicated a greater improvement in the cyclosporin A group relative to the placebo at the end of the 4-week treatment period (P = 0.048 and P = 0.002, for symptoms and signs, respectively). No adverse effects of the treatment with cyclosporin A 0.05% eyedrops were observed. CONCLUSIONS: Topical cyclosporin A 0.05% seems to be safe and have some effect in alleviating signs and symptoms of severe AKC refractory to topical steroid treatment.

Administration, Topical↗
PubMed2004

Outcomes of laser in situ keratomileusis in patients with pigment dispersion syndrome.

PURPOSE: To analyze the outcome of laser in situ keratomileusis (LASIK) in patients with pigment dispersion syndrome (PDS). SETTING: Outpatient ambulatory laser vision correction centers. METHODS: This noncomparative case series reviewed the medical records of 12 patients (22 eyes) who had clinical features consistent with PDS at the time of the initial preoperative refractive evaluation and had LASIK surgery. RESULTS: Twenty eyes (90.9%) of 11 patients had an uneventful course after LASIK and a good final uncorrected visual acuity (mean follow-up 26 months). One patient (2 eyes) with PDS and suspicion of glaucoma on topical beta-blocker therapy had delayed healing, fluctuations in vision, and a lengthy visual recovery. CONCLUSIONS: Corneal findings of PDS do not appear to affect the intraoperative or postoperative outcomes of LASIK. However, patients who have PDS in the context of glaucoma and therapy with an intraocular-pressure-lowering agent may experience delayed healing and a less predictable visual outcome.

Adult↗
PubMed2004

Evolving guidelines for intravitreous injections.

Intravitreous (i.v.t.) injection is increasingly being incorporated into the management of ocular diseases. While only fomivirsen sodium (Vitravene) is currently approved by the Food and Drug Administration as an i.v.t. injection, the number of approved i.v.t. injections indications is anticipated to grow on the basis of promising results from ongoing clinical studies. Despite the potential benefits that may be derived from intraocular injections of different agents, no guidelines have been published previously for i.v.t. injection. The purpose of this document is to identify specific strategies for the delivery of i.v.t. injection that may reduce risks and improve outcomes. Consensus was sought among a panel of investigators, surgeons experienced with this technique, and industry representatives. Objective evidence was sought for all guidelines, but consensus was accepted where evidence remains incomplete. In the absence of either evidence or consensus, the current manuscript identifies outstanding issues in need of further investigation. It is anticipated that more complete guidelines will evolve over time, potentially altering some of the guidelines included here, based on new applications of i.v.t. injection, additional clinical experience, and results of clinical trials.

Humans↗
PubMed2004

Disinfection capacity of PuriLens contact lens cleaning unit against Acanthamoeba.

PURPOSE: The PuriLens contact lens system is indicated for cleaning and disinfection of soft (hydrophilic) contact lenses by means of subsonic agitation to remove lens deposits and microorganisms, and ultraviolet irradiation of the storage solution for disinfection. The capacity of the PuriLens system to disinfect storage solutions contaminated with known concentrations of Staphylococcus aureus, Pseudomonas aeruginosa, and Acanthamoeba species was evaluated. METHODS: An in vitro assessment of the antibacterial and antiparasitic efficacy of the PuriLens system was performed. Separated batches of the storage solution for the cleansing system were contaminated with stock strains of S. aureus and P. aeruginosa. A comparison of the microbiologic content was made between the solution before and after the cycle. RESULTS: The PuriLens system effectively eradicated S. aureus and P. aeruginosa organisms after a 15-minute cycle. However, viable cysts of acanthamoeba were recovered in the solution after the 15-minute cycle. CONCLUSIONS: The PuriLens system is highly efficient in protecting against contamination with common bacterial ocular pathogens. Acanthamoeba cysts, however, can survive in the solution or contact lens bath undergoing integrated subsonic debridement and indirect ultraviolet light disinfection. Use of chemical disinfecting solutions that contain agents such as chlorhexidine or other cationic antiseptics may be advisable in conjunction with use of the PuriLens device, especially in high-risk settings.

Acanthamoeba↗
PubMed2003

Effect of topical fluoroquinolones on the expression of matrix metalloproteinases in the cornea.

BACKGROUND: Matrix metalloproteinases play an important role in extracellular matrix deposition and degradation. Based on previous clinical observations of corneal perforations during topical fluoroquinolone treatment, we decided to evaluate the comparative effects of various fluoroquinolone eye drops on the expression of matrix metalloproteinases (MMPs) in cornea. METHODS: Eighty female Lewis rats were divided into two experimental groups: intact and wounded corneal epithelium. Uniform corneal epithelial defects were created in the right eye with application of 75% alcohol in the center of the tissue for 6 seconds. The treatment groups were tested as follows: 1) Tear drops: carboxymethylcellulose sodium 0.5 % (Refresh, Allergan); 2) Ciprofloxacin 0.3% (Ciloxan, Alcon); 3) Ofloxacin 0.3%(Ocuflox, Allergan); 4) Levofloxacin 0.5%(Quixin, Santen). Eye drops were administered 6 times a day for 48 hours. Rats were sacrificed at 48 hours. Immunohistochemical analysis and zymography were conducted using antibodies specific to MMPs-1, 2, 8 and 9. RESULTS: MMP-1, MMP-2, MMP-8 and MMP-9 expression were detected at 48 hrs in undebrided corneal epithelium groups treated with the topical fluoroquinolones. No statistical difference was observed in quantitative expression of MMPs among ciprofloxacin 0.3%, ofloxacin 0.3%, levofloxacin 0.5%. When the artificial tear group and the fluoroquinolone groups with corneal epithelial defect were compared, increased expression of MMPs was observed as a result of the wound healing process. However, the fluoroquinolone treated group exhibited high statistically significantly levels of MMPs expression. CONCLUSIONS: Our study provides preliminary evidence that topical application of fluoroquinolone drugs can induce the expression of MMP-1, MMP-2, MMP-8 and MMP-9 in the undebrided corneal epithelium compared to artificial tear eye drops.

Administration, Topical↗
PubMed2003

Infectious keratitis after photorefractive keratectomy.

PURPOSE: To elucidate risk factors, microbial culture results, and visual outcomes for infectious keratitis after photorefractive keratectomy (PRK). DESIGN: Multicenter, retrospective chart review, case report, and literature review. METHODS: The records of 12 patients with infectious keratitis after PRK were reviewed. MAIN OUTCOME MEASURES: Causative organism, response to medical treatment, and visual outcome. RESULTS: Infectious keratitis developed in 13 eyes of 12 patients after PRK. Organisms cultured were Staphylococcus aureus (n = 5), including a bilateral case of methicillin-resistant Staphylococcus aureus; Staphylococcus epidermidis (n = 4); Streptococcus pneumoniae (n = 3); and Streptococcus viridans (n = 1). Four patients manipulated their contact lenses, and 2 patients were exposed to nosocomial organisms while working in a hospital environment. Prophylactic antibiotics used were tobramycin (nine cases), polymyxin B-trimethoprim (three cases), and ciprofloxacin (one case). Final best spectacle-corrected visual acuity ranged from 20/20 to 20/100. CONCLUSIONS: Infectious corneal ulceration is a serious potential complication of PRK. Gram-positive organisms are the most common pathogens. Antibiotic prophylaxis should be broad spectrum and should include gram-positive coverage.

Adult↗
PubMed2003

Histoplasma granuloma of the conjunctiva.

PURPOSE: To describe the clinical and pathologic features of a conjunctival granuloma resulting from Histoplasma capsulatum. DESIGN: Clinicopathologic case report. METHODS: Surgical excision of conjunctival lesion, histopathologic study with special stains, and a fluorescent antibody technique. RESULTS: A conjunctiva granuloma was found to contain microorganisms, compatible with H. capsulatum, confirmed by a fluorescent antibody technique. The conjunctiva returned to normal. CONCLUSIONS: A focal granuloma of the conjunctiva contained H. capsulatum in a patient whose recent symptoms suggested primary infection. The conjunctival lesion was similar to mucocutaneous lesions seen in patients with systemic histoplasmosis.

Aged↗
PubMed2003

Recurrence of keratitis after excimer laser keratectomy.

We report 3 patients who experienced a recurrence of nonherpetic keratitis after excimer laser photorefractive surgery. Two patients had a history of culture-positive adenoviral keratoconjunctivitis, and 1 had a clinical diagnosis of Thygeson's superficial punctate keratitis (SPK) prior to excimer laser surgery. Patients should be informed that excimer laser surgery may contribute to a recurrence of keratitis and Thygeson's SPK. Recognition and appropriate treatment can result in resolution and maintenance of a good refractive outcome.

Adult↗
PubMed2003

Effects of topical nonsteroidal antiinflammatory drugs on the expression of matrix metalloproteinases in the cornea.

PURPOSE: To assess the effects of nonsteroidal antiinflammatory drug (NSAID) eyedrops on the expression of matrix metalloproteinases in corneal tissue. SETTING: Ocular Microbiology and Immunology Laboratory, Refractive Surgery Research Laboratory, The Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA. METHODS: Seventy rats were divided into 2 groups: intact and debrided epithelium. Uniform central corneal epithelial defects were created in the right eye of the debrided corneal group. Each group was divided into 4 subgroups, each receiving 1 of the following eyedrops or artificial tears: The 3 NSAIDs were diclofenac sodium 0.1% (Falcon or Voltaren) and preservative-free ketorolac 0.5% (Acular PF). The artificial tears were carboxymethylcellulose sodium 0.5% (Refresh Plus PF). The eyedrops were administered 4 times a day for 1 week. The rats were killed on days 2 and 7. The corneas were excised and processed for immunohistochemical staining, Western blot assay, and zymography studies to determine the localization of the production of the following matrix metalloproteinases (MMPs): MMP-1, MMP-2, MMP-8, and MMP-9. RESULTS: Matrix metalloproteinase-1, MMP-8, and MMP-2 were detected in rat corneas at 48 hours in the debrided and intact epithelium groups treated with NSAID eyedrops. The MMP-1 and MMP-8 expression levels were higher in intact corneas in the diclofenac sodium groups than in the ketorolac and artificial tears groups. The expression was localized mostly in the epithelial cells and occasionally in keratocytes. CONCLUSION: This study provides preliminary evidence that topical application of some NSAIDs can induce the early expression of MMP-1, MMP-2, and MMP-8 in the cornea, suggesting that MMPs play a role in the corneal cytotoxicity of certain NSAIDs.

Administration, Topical↗
PubMed2003

Incidence of intraoperative corneal abrasions and correlation with age using the Hansatome and Amadeus microkeratomes during laser in situ keratomileusis.

To compare the incidence of intraoperative corneal abrasions using the Hansatome (Bausch & Lomb Surgical) and Amadeus (Advanced Medical Optics) microkeratomes and to determine whether there is a correlation between patient age and the occurrence of intraoperative corneal abrasions. Outpatient ambulatory laser vision correction center. The charts of 133 patients (263 eyes) having laser in situ keratomileusis (LASIK) were reviewed retrospectively. The patients were randomized to LASIK performed by 2 surgeons using the same technique with alternative microkeratome selection. The incidence of intraoperative corneal abrasions was significantly higher with the Hansatome microkeratome than with the Amadeus microkeratome (P =.014). There was a significant correlation between increasing patient age and the incidence of corneal abrasions with both microkeratomes (P<.05). Laser in situ keratomileusis surgeons should be aware that certain microkeratome designs pose a higher risk for intraoperative corneal abrasions and that older patients are more susceptible to intraoperative corneal epithelial injury. These patients should be informed accordingly for appropriate consent.

Adult↗
PubMed2003

Ocular toxicity of intravitreal trovafloxacin in the pigmented rabbit.

PURPOSE: Trovafloxacin is an expanded spectrum, newer-generation fluoroquinolone antibiotic with improved Gram-positive and anaerobic activity compared with existing quinolones, while maintaining Gram-negative activity comparable to ciprofloxacin. Given its broad spectrum of activity, trovafloxacin may have potential use for treatment of acute bacterial endophthalmitis. This study examined the toxicity of intravitreally administered trovafloxacin in the pigmented rabbit eye. METHODS: Doses of trovafloxacin ranging from 12.5 microg to 1000 microg were injected into the mid-vitreous of Dutch Belted rabbit eyes. Clinical examination was performed at 1, 3, and 14 days following injection. Animals were sacrificed and eyes were enucleated 14 days following injection. Light microscopy (LM) and transmission electron microscopy (TEM) studies of the optic nerve head, medullary ray, and inferior retina were performed to determine toxicity. RESULTS: At intravitreal doses of 500 microg and less, no toxicity was observed at the ophthalmoscopic or light microscopic level. By TEM, a dose-dependent increase in injury to retinal pigment epithelium, photoreceptors, and nerve fibers in the optic nerve head and medullary ray was observed from 50 microg to 500 microg. No toxicity was noted at doses of 12.5 microg and 25 microg. At doses of 750 microg and above, edema of the medullary ray was noted on ophthalmoscopy. Swelling of the peripapillary medullary ray and necrosis of the inferior retina were evident on LM. CONCLUSION: Intravitreal trovafloxacin doses of 50 microg and higher in the pigmented rabbit eye cause retinal and nerve fiber injury. Intravitreal doses 25 microg and lower appear to be safe, with no evidence of ocular toxicity.

Animals↗
PubMed2003

Colchicine in tear fluid of treated patients with familial Mediterranean fever.

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.

Adult↗
PubMed2002

Phakic intraocular lenses and refractory lensectomy for myopia.

Phakic intraocular lens implantation (IOLs) and clear lens extraction for high to extreme myopia have grown in popularity recently as a consequence of potentially unsatisfactory results with corneal refractive surgery in higher ranges of refractive errors. The refractive outcome of these alternative modalities has been encouraging to date, yet the potential for significant complications exists. Current evidence shows that the risk of retinal detachment after clear lens extraction for myopes is high. Trials with angle-supported phakic IOLs revealed unacceptable rates of pupillary ovalization, IOL rotation, and endothelial cell loss. Iris-fixated and posterior chamber phakic IOLs have proven sufficient safety, but long-term follow-ups of current cohorts are still to be awaited. The implantation of either of the latter two phakic IOLs followed by laser in situ keratomileusis or photorefractive keratectomy (bioptics) provides another option in refractive surgery for high ametropia.

Anterior Chamber↗
PubMed2002

The relationship between long-term contact lens wear and corneal thickness.

PURPOSE: The purpose of this study is to assess the effects of long-term contact lens wear on corneal thickness and to compare differences based on rigid versus soft lens material. METHODS: This analysis included scanning slit topographic imaging (Orbscan, Bausch & Lomb, Rochester, NY) performed on 124 consecutive patients (248 eyes), who underwent comprehensive evaluations in consideration of refractive surgery by one surgeon. RESULTS: Sixty-two 62 patients (124 eyes) who had not previously worn contact lenses had a least-squares mean pachymetry of 546.4 microm +/-3.5 SE. Thirty-nine patients (78 eyes) who had previously worn soft contact lenses for an average of 16 years had a least-squares mean pachymetry of 543.2 microm +/-3.8 SE. Twenty-three patients (46 eyes) who had worn rigid contact lenses for an average of 19 years had a least-squares mean pachymetry of 509.4 microm +/-6.9 SE. Mean pachymetry differed significantly between eyes wearing rigid lenses versus no lenses (P<0.0001) and between eyes wearing rigid lenses versus soft lenses (P=0.0002). CONCLUSION: Long-term rigid contact lens wear is associated with a decrease in the average central-corneal thickness (CCT) by an average of 37 microm, in this group of otherwise healthy eyes, compared to no contact lens wear. Long-term soft contact lens wear did not appear to significantly change corneal thickness compared to no contact lens wear. Caution should be exercised when screening patients with a history of long-term rigid contact lens wear for possible excimer-laser photoablative correction.

Contact Lenses↗
PubMedDate not supplied

Risk factors in interface epithelialization after laser in situ keratomileusis.

PURPOSE: To identify risk factors associated with primary and recurrent epithelial ingrowth after laser in situ keratomileusis (LASIK) requiring surgical debridement. METHODS: Charts of patients who required single or multiple surgical debridements of epithelial ingrowth were reviewed retrospectively and analyzed to identify preoperative, intraoperative, and postoperative risk factors. RESULTS: Fourteen of 22 patients had epithelial ingrowth that required a single surgical removal. These were mostly associated with the surgeon's learning curve, epithelial injury, and enhancement by lifting the flap. Multiple surgical debridements were required in eight patients and some of these were associated with epithelial basement membrane degeneration and a history of type I diabetes. CONCLUSIONS: Refractive surgeons should be aware of surgical and non-surgical ocular and systemic risk factors associated with both primary and recurrent epithelial ingrowth after LASIK to appropriately consent patients seeking refractive surgery. Type I diabetes may increase the risk of epithelial downgrowth in LASIK.

Adult↗
PubMedDate not supplied

Patients with prion disease: planning for eye surgery.

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.

Equipment Contamination↗