Trifluoperazine inhibits phagocytosis in a macrophagelike cultured cell line.

Trifluoperazine, a drug that binds to Ca2+-calmodulin and inhibits its interaction with other proteins, was found to inhibit growth and phagocytosis in a macrophagelike cell line, J774.16. Both effects were reversible and occurred at the same concentrations of drug (25--50 microM) that inhibited the activation of cyclic nucleotide phosphodiesterase by calmodulin in vitro. Fc-mediated phagocytosis was also depressed by W-7, a sulfonamide derivative that inhibits the activity of Ca2+-calmodulin. In contrast, taxol, a drug that stabilizes cellular microtubules, had no effect on Fc-mediated phagocytosis although it inhibited cell growth at nanomolar concentrations. The inhibitory effects of trifluoperazine and W-7 on phagocytosis suggest that calmodulin may be involved in this complex cellular function.

Myopic intrastromal photorefractive keratectomy with the neodymium-yttrium lithium fluoride picosecond laser in the cat cornea.

OBJECTIVE: To evaluate the refractive effects of myopic intrastromal photorefractive keratectomy (IPRK) with the neodymium-yttrium lithium fluoride (Nd-YLF) picosecond laser. METHODS: A 1053-nm Nd-YLF picosecond laser was used to produce myopic IPRK in cat corneas at threshold energy densities. Preoperative corneal topography and ultrasonic pachymetry were performed followed by IPRK in one eye each of 21 cats. No anti-inflammatory medications were administered. Postoperative corneal topography, ultrasonic pachymetry, and slit-lamp examination were performed at scheduled intervals. RESULTS: An average topographic flattening of 11.4 diopters and pachymetric thinning of 50 microns at the center of the treatment zone were observed by 6 weeks following treatment. The average diameter of the zone of flattening was 5.1 mm at 6 weeks and 6.0 mm at 12 weeks postoperatively. At 6 months postoperatively, the average central corneal power was unchanged, while the average central thickness had returned to the preoperative value. A mild subepithelial haze was detected at 1 month following IPRK, which was barely perceptible at the second through sixth months. Regression of the topographic effects of PRK was not observed. CONCLUSION: Intrastromal PRK with the Nd-YLF picosecond laser produces central flattening of the cat cornea with barely perceptible stromal haze and no regression of topographic effect after 6 months in the absence of treatment with anti-inflammatory agents.

Effect of gas-permeable contact lenses on the endothelium of corneal transplants.

The effects of gas-permeable contact lens wear on the density and morphologic characteristics of corneal endothelial cells were prospectively studied by wide-field specular microscopy in 18 eyes that had undergone keratoplasty at least 14 months previously. Daily-wear rigid gas-permeable lenses were fitted to allow as much movement and tear exchange as possible. There was no evidence of morphologic instability of the endothelial cells during the course of the study, with a mean duration of lens wear of 9.8 months. Although there is concern over adverse effects associated with polymethylmethacrylate contact lens wear, this study suggests that the endothelium of a corneal transplant tolerates rigid gas-permeable lens wear without adverse effect during a limited period of follow-up.

Influence of haptic materials on the adherence of staphylococci to intraocular lenses.

A recent case-control study indicated that the insertion of an intraocular lens with polypropylene (Prolene) haptic materials was a significant risk factor for postoperative endophthalmitis (odds ratio = 4.5, P < .01). In the present study, we used quantitative techniques to evaluate adherence of Staphylococcus epidermidis to two intraocular lens types--lenses with polypropylene haptic materials and all-polymethyl methacrylate optic and three-piece all-polymethyl methacrylate lenses--using a quantitative culture method, a radioisotope technique, and scanning electron microscopy. All three methods demonstrated approximately twice as many bacteria adherent to lenses with polypropylene haptic materials as to all-polymethyl methacrylate lenses. Scanning electron microscopy showed preferential bacterial adherence to the polypropylene haptic materials. These data provide a pathogenic mechanism to explain our epidemiologic findings of an increased risk of postoperative endophthalmitis associated with implantation of intraocular lenses with polypropylene haptic materials.

Blepharitis.

Blepharitis is an acute or chronic inflammatory process involving the eyelids that is frequently associated with conjunctivitis. In its many clinical forms, blepharitis is one of the most common diseases seen by ophthalmologists; yet it remains a diagnostic and therapeutic challenge. This article reviews the clinical presentation, classification, diagnosis, etiology and pathogenesis, and treatment of blepharitis.

Repair of Descemet's membrane detachment with the assistance of intraoperative ultrasound biomicroscopy.

PURPOSE: To evaluate the ability of ultrasound biomicroscopy to monitor the repair of large Descemet's membrane detachments. METHODS: Intraoperative ultrasound biomicroscopy was performed in two patients who had undergone previous unsuccessful surgical repair of large Descemet's membrane detachments. RESULTS: Ultrasound biomicroscopy visualized and located Descemet's membrane detachment and verified proper suture placement and membrane repositioning. CONCLUSIONS: Ultrasound biomicroscopy is a useful tool to guide surgical repair of Descemet's membrane detachments, particularly when hazy media prevent satisfactory visualization.

Pseudophakic bullous keratopathy.

We reviewed the records of all patients with pseudophakic bullous keratopathy (271 eyes, 251 patients) seen during a six-month period to determine predisposing factors, associated problems, current management, and visual outcome. Pseudophakic bullous keratopathy was associated most frequently with anterior chamber intraocular lenses in general (155 of 271), and with Leiske style lenses in particular (100 of 271). It was associated with a visual acuity of 20/200 or less in 206 eyes and a visual acuity of counting fingers or less in 129 of the eyes at the initial examination. Penetrating keratoplasties had been performed in 189 of the eyes. After penetrating keratoplasty, 108 of 189 of the eyes had a visual acuity of 20/200 or less (mean follow-up, 15 months). Visual acuity improved with longer follow-up, and among patients with a minimum follow-up of two years, 23 of 36 eyes had a visual acuity of 20/100 or better. Most grafts were clear (145 of 189). Pseudophakic bullous keratopathy was associated with marked visual loss, which was permanent despite clear grafts in 29 of 92 eyes followed-up for one year or longer.

Wound healing following intrastromal photorefractive keratectomy with the Nd:YLF picosecond laser in the cat.

BACKGROUND: We studied the histopathology of the stromal wound healing response in the cat cornea following intrastromal photorefractive keratectomy (IPRK) with the Nd:YLF picosecond laser. METHODS: Intrastromal PRK was performed in the anterior stroma of cat corneas with the Nd:YLF picosecond laser. The cats were sacrificed at predetermined intervals ranging from immediately to 6 months postoperatively. Effects of the laser treatment on the epithelium, Bowman's layer, stroma, and the endothelium were evaluated using light and scanning electron microscopy. No anti-inflammatory agents were used. RESULTS: Intrastromal PRK resulted in no perceptible damage to the corneal epithelium or Bowman's layer either acutely or at 6 months. The corneal stroma showed multiple cavitations immediately after intrastromal PRK, which collapsed over several hours, followed by thinning of the cornea over 2 weeks. At 1 month, the stromal collagen was abnormal with surrounding hypercellularity. The endothelium showed no injury, acutely or at 6 months. No thermal effects on stromal collagen were observed at 6 months, and disruption of the lamellar pattern was not apparent after the cavitation bubbles were reabsorbed. CONCLUSION: Intrastromal PRK can effectively remove stromal tissue without acute damage to the adjacent lamellae, epithelium, or endothelium. There is a transient cellular wound healing response associated with a transient stromal collagen abnormality at 2 weeks to 1 month, which was not apparent 2 months after the procedure.

Ultrasound biomicroscopy of intrastromal photorefractive keratectomy with the Nd:YLF picosecond laser.

PURPOSE: To evaluate corneal morphology in vivo following intrastromal photorefractive keratectomy (IPRK) with the Nd:YLF picosecond laser, using the ultrasound biomicroscope. MATERIALS AND METHODS: Myopic intrastromal PRK was performed in the anterior stroma of cat corneas with the neodymium:yttrium lithium fluoride (Nd:YLF) picosecond laser. Periodic examination of the treated corneas up to 6 months postoperative was performed with high resolution ultrasound biomicroscopy. Corneal thickness, depth of the laser patterns from the corneal surface, alignment of the laser treatment, extent of stromal opacification until resolution, and contour of the corneal surface were measured with the ultrasound biomicroscope throughout follow up. RESULTS: The treated corneas were thickened on ultrasonic biomicroscopy measurement immediately after intrastromal PRK and revealed a densely echogenic shadow parallel to the corneal surface at the treatment site. There was increased stromal echogenicity denoting mild edema. The echoes decreased over time and appeared thinner at 2 months compared to the preoperative and immediate postoperative measurements. At 6-month follow up, the treated corneas were echolucent on ultrasonic biomicroscopy. CONCLUSION: The ultrasound biomicroscope might become a helpful tool in assessing accuracy of treatment parameters of intrastromal PRK as well as in monitoring the response of the cornea to treatment.

Clinical analysis of the neodymium:YLF picosecond laser as a microkeratome for laser in situ keratomileusis. Partially Sighted Eye Study.

PURPOSE: To evaluate the use of a picosecond neodymium:YLF (Nd:YLF) laser as a nonmechanical intrastromal microkeratome. SETTING: Universita Cattolica del Sacro Cuore, Rome, Italy. METHODS: An intrastromal spiral disc pattern of picosecond laser pulses was used to create a corneal flap for laser in situ keratomileusis (LASIK) in 14 partially sighted eyes. RESULTS: Flaps with a 6.0 mm diameter and 180 to 200 microns depth were successfully created in most cases. The underlying stroma was treated with a Lambda Physik excimer laser using a 3.5 to 4.5 mm optical zone. Patients were divided into 3 groups for target corrections of 5.0, 10.0, and 15.0 diopters of myopia. Good corneal clarity and refractive undercorrection were recorded in each group 6 months postoperatively. The undercorrection was due in part to the limited optical zone of the laser's delivery system. Some flap decentration was noted. CONCLUSION: This pilot study indicates that the Nd:YLF picosecond laser may be clinically applied for creating corneal flaps for LASIK. Further refinements of the laser delivery system will include enlargement of the flap diameter and improvements in flap centration. The use of a femtosecond laser may expand the capabilities and precision of this technology.

Mass spectrometry analysis of the by-products of intrastromal photorefractive keratectomy.

BACKGROUND AND OBJECTIVE: To determine the nature and chemical composition of the cavitation bubbles generated by intrastromal photorefractive keratectomy (IPRK) with the Neodymium: Yttrium Lithium Fluoride (Nd:YLF) picosecond laser. MATERIALS AND METHODS: IPRK was performed on the corneas of three fresh human cadaver eyes with the Nd:YLF picosecond laser. High energy levels of 200 mJ/pulse to 300 mJ/pulse were used to produce the maximum amount of gas within the corneal stroma. The cavitation bubbles produced in the stroma were aspirated using a gas-tight syringe connected to a valve, and the specimens were analyzed with a mass spectrometer. RESULTS: The experiment was performed on three different occasions using one cadaver eye in each experiment. The analysis consistently revealed a mixture of carbon dioxide, carbon monoxide, water vapor, oxygen, and nitrogen. Atmospheric control samples also revealed oxygen and nitrogen. No other components were detected. CONCLUSION: The gaseous by-products of IPRK with the picosecond laser result from the simple breakdown of stromal tissue and contain no toxic or unexpected components. We found that these gaseous products are capable of rapid elimination by absorption or diffusion out of the intact cornea.

Prophylaxis of endophthalmitis with topical povidone-iodine.

The authors conducted an open-label nonrandomized parallel trial to examine whether the preoperative application of povidone-iodine to the ocular surface reduces the incidence of endophthalmitis after intraocular surgery. During an 11-month period, topical 5% povidone-iodine was used to prepare the conjunctiva in 1 set of 5 operating rooms, while silver protein solution was used in another set of 5 rooms. In all cases, surgeons continued to use their customary prophylactic antibiotics. A significantly lower incidence of culture-positive endophthalmitis (P less than 0.03) was observed in the operating rooms using povidone-iodine (2 of 3489 or 0.06%) compared with those using silver protein solution (11 of 4594 or 0.24%). Use of topical povidone-iodine in over 3000 cases was not associated with any adverse reactions. In a majority of the observed cases of endophthalmitis, some form of intraoperative communication with the vitreous cavity existed.

Computerized preparation of a scientific poster.

We prepared an attractive and effective poster using a Macintosh computer and Laserwriter and Imagewriter II printers. The advantages of preparing the poster in this fashion were increased control of the final product, decreased cost, and a sense of artistic satisfaction. Although we employed only the above mentioned computer, the desktop publishing techniques described can be used with other systems.

The collagen shield as a collagenase inhibitor and clinical indicator of collagenase activity on the ocular surface.

Collagen shields applied to the corneas of patients with bacterial keratitis degrade rapidly, often within a few hours. Once treatment brings the infection under control, subsequently applied collagen shields degrade more slowly. In vitro models were established to evaluate the significance of these observations. Twenty-four and 72-hour collagen shields were incubated with collagenase from Clostridium histolyticum. The in vitro rate of digestion of the shields was directly proportional to the concentration of collagenase, with the rate of digestion of the 24-hour shields being greater than that of the 72-hour shields. Therefore, the rate of collagen shield degradation may be a clinically useful index of collagenase activity on the ocular surface. Ultrastructural studies of collagen shields from patients with acute bacterial keratitis revealed irregular degradation of shield matrix with no evidence of adherence of microorganisms or inflammatory cells. Co-incubation of deepithelialized rabbit corneas and collagen shields resulted in inhibition of the digestion of the rabbit corneas when the weight:weight ratio of collagen shield:rabbit cornea was increased to greater than or equal to 2:1. Collagen shields may inhibit corneal collagen degradation in infectious ulceration and melting disorders by effectively competing for collagenase on the ocular surface.