Lagrangian simulation of oil trajectories in the Florida Straits.

A Lagrangian floating oil trajectory model is developed to simulate a continuous surface spill in the Florida Straits. The trajectories are initiated at locations representative of exploratory drilling sites around Cuba's Exclusive Economic Zone and integrated for ten days. The simulation is initialized for different seasons, using leeway-corrected observed winds, ocean currents, different climatologies, and a first-order Markov Lagrangian Stochastic Model. A Monte-Carlo scheme is used to parameterize oil weathering processes collectively. Overall, the simulations exhibit a strong seasonal dependence, where the Florida coast is most affected during the summer and the Cuban coast in the winter. Drilling sites at the center of the Straits show the largest impact on Florida. Cuba is most affected by shoreline locations. A significant amount of oil reaches the Florida coastline within two to ten days, and Cuba is potentially affected within hours. Many simulations project impacts for the Florida Keys, South Florida, and the north shore of Cuba.

Intraocular molluscum contagiosum after a corneoscleral laceration.

PURPOSE: To report molluscum contagiosum as a cause of severe posttraumatic intraocular inflammation. METHODS: A 9-year-old girl developed severe intraocular inflammation in the right eye after a corneoscleral laceration. She underwent vitrectomy, and bacterial and fungal cultures of intraocular fluids were negative. A pedunculated white-tan mass removed from her right optic nerve head was sent for histologic evaluation. RESULT: Histologic examination of the tissue showed stratified keratinizing squamous epithelium with intracytoplasmic inclusions consistent with molluscum contagiosum. CONCLUSIONS: It is likely that infected epithelial cells were implanted at the time of injury. Vitrectomy as debridement was curative.

Two shielded 'bullet' probes for panoramic endoillumination.

Panoramic viewing during vitrectomy offers significant advantages over conventional viewing in many cases and is being used with increasing frequency. Two endoillumination probes that reduce the glare occurring with use of the existing panoramic endoillumination probes were developed. They allow easier viewing of the fundus in eyes with poor media and improve the visualization of the vitreous fibers adjacent to the probe in eyes with clear media. One probe is used for endoillumination alone, and the other has a pick to be used for bimanual dissection. The two probes have been used in more than 100 vitrectomies for various indications, and they give excellent illumination with reduced glare.

Lensectomy, vitrectomy indications, and techniques in cataract surgery.

Removal of a cataract during a vitrectomy can be performed to improve visualization for the surgeon or to facilitate visual rehabilitation for the patient. Because aphakic eyeglasses or contact lenses are often poor options to correct aphakia, placement of an intraocular lens during or after a vitrectomy is becoming increasingly common. A cataractous lens can be removed by pars plana lensectomy, phacoemulsification, or extracapsular cataract extraction. Options for intraocular lens placement include no intraocular lens, anterior chamber lens or sutured posterior capsular lens in the absence of capsular support, "in-the-bag" posterior capsular lens, or sulcus-fixated posterior capsular lens. This article reviews the current indications and techniques for cataract removal with or without intraocular lens placement in patients undergoing vitrectomy.

Results of surgical treatment of recent-onset full-thickness idiopathic macular holes.

OBJECTIVE: To investigate whether the visual prognosis after macular hole surgery was different between recent and older holes and to evaluate preoperative characteristics and variations in surgical technique that may influence outcome. DESIGN: The medical charts of all our patients who underwent surgery for a full-thickness macular hole were retrospectively reviewed. PATIENTS: Forty-eight eyes of 48 patients in the "early" group (symptoms < or = 6 months), and 20 eyes of 19 patients in the "late" group (symptoms > 6 months). INTERVENTION: Vitrectomy, separation of the posterior hyaloid, gas tamponade, and instructions to be face down for 1 week. Most patients had epiretinal membrane dissection. MAIN OUTCOME MEASURES: The early and late groups were compared regarding anatomic and visual outcomes. In the early group we evaluated the effect on outcome of the stage of the hole, intraocular tamponade, membrane dissection, and travel distance. RESULTS: Median postoperative visual acuity in the early group was 20/40 at 3, 6, and 12 months. Fifteen (56%) of 27 patients gained at least three lines of vision at 12 months. Anatomic success was seen with one operation in 75% (36/48), and with two operations in 87.5% (42/48). Stage 2 holes had a final anatomic success rate of 94.4%. Of respondents to an informal survey, 63.4% (26/41) believed that vision was greatly improved, and 70.3% (26/37) said that they would definitely choose surgery again. In the late group, median postoperative visual acuity was 20/100 at 6 months, compared with 20/142 preoperatively. Closure of the hole with one operation was seen in 60% (12/20) of the patients in the late group. CONCLUSIONS: Surgery in patients with recent macular holes has a better prognosis for visual rehabilitation than with older holes and appears to be considered beneficial by most patients.

Tissue plasminogen activator and Staphylococcus epidermidis endophthalmitis.

OBJECTIVE: To determine whether intraocular administration of tissue plasminogen activator (tPA) speeds clearance of inflammatory debris or prevents fibroproliferative complications in an animal model of endophthalmitis. METHODS: Aphakic rabbits were given an intraocular dose of Staphylococcus epidermidis organisms known to cause moderate inflammation and to self-sterilize. They were then randomized to receive either tPA or saline injections 2 and 3 days after inoculation. All eyes were graded by one masked clinician seven times, 1 to 28 days after infection. Vitreous samples from selected eyes were cultured. RESULTS: Treated and control eyes were found to have no significant difference in inflammatory scores. Although the eyes treated with tPA had more retinal detachments and more positive cultures than control eyes, these numbers were not statistically significant (P = .44 to .71). CONCLUSION: Fibrinolysis with intraocular tPA does not accelerate clearance of inflammation nor decrease fibroproliferative complications in this animal model of endophthalmitis.

External argon laser drainage of subretinal fluid using the endolaser probe.

The results of 200 consecutive scleral buckling procedures in which the argon endolaser probe was used to create a choroidotomy for drainage of subretinal fluid are reported. This technique was used in any case requiring drainage and was specifically employed in cases in which needle drainage was contraindicated because the detachment was shallow. The argon laser was set at 0.2 seconds, 1.25 watts, and was used with the endolaser probe held adjacent to, but not touching, the choroid. Drainage was successfully accomplished in 98% of cases. Rates of subretinal hemorrhage, retinal incarceration, and perforation related to laser drainage were 5.5%, 2.5%, and 1%, respectively. No large or submacular subretinal hemorrhages occurred. This technique appears to be particularly promising for drainage of shallow retinal detachments.

An illuminated cannula for viscodelamination.

A fiberoptic illuminated infusion cannula for posterior segment surgery allows the introduction of viscoelastic substances under preretinal membranes in diabetics, defining the vascular epicenters and making scissors delamination easier and safer. This technique has been most helpful in diabetics who have an attached posterior hyaloid. It appears to reduce the incidence of posterior breaks. We have used this instrument successfully in 12 patients with diabetes who have severe fibrovascular proliferation with or without retinal detachment.

Nd:YAG laser photodisruption of the lens nucleus before phacoemulsification.

We studied the use of Q-switched Nd:YAG laser pulses to soften sclerotic lens nuclei before phacoemulsification. We obtained 105 lens nuclei from extracapsular cataract extractions, graded them for degree of sclerosis, and randomized them into laser treatment (53 lenses) or control groups (52 lenses). The treated lenses received laser pulses until confluent pits and clefts were visible. All lenses were phacoemulsified and the times recorded. Nd:YAG laser pretreatment decreased phacoemulsification time in all grades. In moderately sclerotic nuclei, average phacoemulsification time was reduced from 40.1 to 23.9 seconds (40.4%). The nuclei of ten lenses obtained from intracapsular cataract extractions were treated intracapsularly, and the posterior capsule was inadvertently ruptured in five.

An instrument to aid intracapsular cataract extraction of dislocated lenses.

Techniques for surgical removal of a dislocated lens have evolved considerably in the past 30 years. There has been a change in preference from open-sky techniques to the use of automated vitrectomy instruments. We introduce an instrument which may be useful in selected patients with dislocated lenses. This instrument is placed through the pars plana to entrap the lens anteriorly without trauma to the retina or ciliary body. Cryoextraction of the lens through a limbal incision is then performed. We feel this instrument will be most useful in the management of a dislocated nucleosclerotic lens.

Drug-induced acute transient myopia with retinal folds.

A patient was seen with acute bilateral transient myopia, shallowing of the anterior chamber, and radiating perimacular folds. This was believed to be a drug reaction. A fluorescein angiogram was performed which showed no retinal edema. A number of pathophysiologic mechanisms have been proposed for acute transient myopia, but the findings in this patient support ciliary body swelling as the cause of the changes in the eye. This swelling of the ciliary body results in a forward rotation of the lens-iris diaphragm and the vitreous, which causes both the myopia and the retinal folds.