Severe penetrating ocular injury from ninja stars in two children.

The authors describe two cases of penetrating ocular trauma in children resulting from ninja stars. In the first case, despite a scleral laceration, loss of iris tissue, and a vitreous hemorrhage, the child had a good result with a final best corrected visual acuity of 20/20. Unfortunately, the child in the second case did not fare as well. In this case, the child suffered a large corneal laceration and traumatic cataract. He ultimately required a penetrating keratoplasty, and he is currently being treated for amblyopia, strabismus, and elevated intraocular pressures. His best corrected visual acuity is 20/70.

Chronic exposure keratopathy complicating surgical correction of ptosis in patients with chronic progressive external ophthalmoplegia.

PURPOSE: To report chronic exposure keratopathy related to surgical ptosis correction in patients with chronic, progressive, external ophthalmoplegia. METHODS: Case reports of three patients with chronic exposure keratopathy following blepharoptosis surgery. RESULTS: We report three patients with chronic progressive external ophthalmoplegia with chronic corneal complications after surgical ptosis repair. All three gave a history of blepharoptosis and extraocular muscle dysfunction. Each presented with chronic corneal ulceration. All had histories suggestive of ophthalmoplegia. Treatment of corneal ulceration necessitated hospitalization and surgical intervention. CONCLUSION: Patients with chronic, progressive, external ophthalmoplegia have little ability to properly protect the eye from exposure and are at risk for corneal damage. A thorough ophthalmic history and examination before ptosis surgery may prevent the corneal complications resulting from surgical intervention.

Identification of a herpes simplex virus-induced dendrite in an eye-bank donor cornea.

PURPOSE: To demonstrate the presence of an active herpetic dendrite in an eye-bank cornea. CASE REPORT: One eye-bank cornea was studied. Viral cultures and polymerase chain reaction (PCR) testing were performed 4 days after tissue preservation. The presence or absence of herpes simplex virus (HSV) type 1 was investigated. RESULTS: The presence of an active HSV dendrite in an eye-bank cornea was verified. HSV type 1 was confirmed using PCR amplification and restriction endonuclease DNA fragment analysis. CONCLUSION: This case suggests that HSV may remain viable in stored corneal tissue at 4 degrees C.

Mini radial keratotomy reduces ocular integrity. Axial compression in a postmortem porcine eye model.

OBJECTIVE: This study aimed to examine ocular rupture force in pig eyes after "minimally invasive radial keratotomy" (MRK) and standard radial keratotomy (SRK). DESIGN: Experimental study. MATERIALS: A total of 71 pairs of pig eyes (51 control eyes) were examined. INTERVENTION: An axial-torsional Materials Testing System (MTS, Eden Prairie, MN) was used to apply blunt force to the corneal surface. A force transducer measured the rupture forces in control eyes and in eyes with MRK or SRK. Five groups of paired eyes were compared: 2.0-mm MRK versus control (N = 12), 3.5-mm MRK versus control (N = 21), 6.5-mm SRK versus control (N = 18), SRK versus 3.5-mm MRK versus 2.0-mm MRK (N = 10). MAIN OUTCOME MEASURE: Ocular rupture force (newtons) was measured. RESULTS: The mean rupture force in newtons was 746.3 for control eyes, 514.2 for 2.0-mm MRK, 353.1 for 3.5-mm MRK, and 246.2 for SRK. Analysis of variance showed a statistically significant difference (P < or = 0.04) between paired comparisons. CONCLUSION: The MRK and SRK significantly weakened ocular integrity compared with control eyes not operated on. MRK required significantly more force to rupture than SRK. MRK eyes, however, ruptured at 50% to 70% of the force required to rupture eyes not operated on. Any patient considering radial keratotomy should be counseled about the risk of greater ocular damage in trauma.

Corneal lenticular wrinkling after automated lamellar keratoplasty.

PURPOSE: To report complications of automated lamellar keratoplasty in two eyes of two patients. METHODS: Case reports. Two eyes of two patients underwent automated lamellar keratoplasty for myopia. Both patients complained of visual distortion and glare in the postoperative eye. RESULTS: The postoperative eye of both patients showed evidence of wrinkling of the corneal lenticule accompanied by irregular astigmatism. Patient 1 showed persistent lenticular wrinkling and corneal scarring 2.5 years later. Patient 2 showed evidence of interface scar and overcorrection. CONCLUSION: The use of a microkeratome can be complicated by lenticular displacement and wrinkling, resulting in visual aberration for the patient.

Cell cycle kinetics in pterygium at three latitudes.

The cell cycle kinetics of 93 specimens of pterygial tissue, as well as 19 specimens of normal conjunctiva, from patients at three sites representing three different latitudes (Singapore, 1 degree; Hong Kong, 22 degrees; and Little Rock, Arkansas, 34 degrees) were evaluated by flow cytometry. The results showed no difference in cellular proliferation patterns between pterygial and conjunctival tissue at any of the sites, suggesting that pterygium is not a disorder of excess cellular proliferation. Transmission electron microscopy showed extracellular matrix to be a prominent component of pterygium. Cellular proliferation patterns of primary and recurrent pterygium were not significantly different from each other. Factors associated with increased incidence of pterygium included male sex, outdoor occupation, and advanced age.

Nd:YAG laser treatment of retained Descemet's membrane after penetrating keratoplasty.

Retention of the host's Descemet's membrane is an unusual complication of penetrating keratoplasty. The membrane may opacify and even threaten the health of the transplant. Following creation of a central opening with the Nd:YAG laser in such a case, visual acuity improved from counts fingers at 5 ft to 20/100.

Collagen-based drug delivery and artificial tears.

For patients with conditions requiring chronic rather than acute therapy, the advantages of collagen shields in providing high and sustained levels of drugs and/or lubricants to the cornea are outweighed by the difficulty of insertion of the shield and the problem of blurred vision. We have developed a delivery system in which collagen pieces suspended in a viscous vehicle can be instilled into the lower forniceal space, thereby simplifying application and reducing blurring of vision. The collagen pieces (Collasomes) can be formulated with various constituents such as antibiotics or cyclosporine, or with chemical alterations such as the inclusion of a lipid (Lacrisomes) for the treatment of dry eyes. In the normal eyes of volunteers, Collasomes hydrated in a solution of sodium fluorescein and suspended in a methylcellulose vehicle as a model for delivery of water-soluble drugs produced fluorescein concentrations 17 to 42 times higher in the cornea and 6 to 8 times higher in the aqueous humor, compared with fluorescein-containing vehicle alone. In a preliminary controlled study, 76% of patients with moderately severe keratoconjunctivitis sicca (KCS) preferred Lacrisomes to the vehicle control because of a more soothing effect and longer duration of comfort. All preparations were well tolerated by all study subjects. Current studies involve improving drug delivery by chemically modifying the collagen molecule to slow diffusion of the drug from the Collasome matrix, as well as varying the amount of cetyl alcohol and combining it with modified collagen in Lacrisomes to maximize comfort in patients with dry eyes.

Topical bupivacaine and proparacaine: a comparison of toxicity, onset of action, and duration of action.

Bupivacaine is a local ocular anesthetic with a long duration of action when administered by retrobulbar injection. To determine the potential for the use of bupivacaine as a topical ocular anesthetic, the onset and duration of action and toxicity of various concentrations of bupivacaine were studied after instillation in rabbit eyes. The onset and duration of action were not significantly different from that of topical 0.5% proparacaine. Increasing the pH of the bupivacaine solution from 5.7 to 6.5 nearly doubled the duration of action, but the increase was not sufficient to be clinically important. Slit lamp biomicroscopic examination and scanning electron microscopy showed that bupivacaine was less toxic to the corneal epithelium than 0.5% proparacaine. Healing after keratectomy was significantly more rapid in eyes treated with 0.75% bupivacaine, compared with eyes treated with 0.5% proparacaine. These results suggest that bupivacaine may be less toxic to the corneal epithelium than proparacaine and could be clinically useful for topical ocular anesthesia, particularly if pharmacologic modifications can increase the duration of anesthesia provided by this drug.

Vancomycin-enriched corneal storage medium.

Antibiotics in a corneal preservation solution probably have little effect during storage at 4 C, but are effective as the tissue is warmed. The tissue acts as a sponge, soaking up the antibiotic from the solution and releasing it into the eye, where the bactericidal effect is achieved. Currently, high concentrations of gentamicin (relative to the minimal inhibitory concentration) are used in the preserving solution for this purpose. Presumably, proportionately high concentrations of any proposed new antibiotic added to supplement the bactericidal effect of gentamicin, such as the vancomycin used in this study, would be required. However, neither the ability of donor tissue to tolerate high concentrations of vancomycin nor the stability of vancomycin at neutral pH in appropriate storage media has been documented. We evaluated the addition of vancomycin (100 micrograms/ml) to two corneal storage media that contained gentamicin in terms of stability of the antibiotic in solution and the effect on the endothelial cells of donor tissue stored for two weeks at 4 C. Vancomycin was stable in solution at neutral pH (7.2) during the five-month period of the study; the concentration exceeded 90 micrograms/ml for the first five weeks. The endothelial cells from donor tissue stored in the vancomycin-enriched media showed no notable differences from those stored in the same media without vancomycin in terms of cell shape, cell borders, cell swelling, and apical holes. The stability of vancomycin in storage and the absence of endothelial toxicity in vitro support the potential use of this antibiotic as a supplement to gentamicin for the prevention of endophthalmitis in patients receiving corneal transplants.

Optisol corneal storage medium.

Optisol is an investigational, intermediate-term corneal storage medium containing chondroitin sulfate and dextran to enhance corneal dehydration during storage. We used scanning electron microscopy to grade endothelial cell morphologic characteristics in terms of cell shape, cell borders, cell swelling, and apical holes in pairs of corneas stored in Optisol and Dexsol. Optisolstored corneas showed significantly fewer morphologic changes after 14 days at 4 degrees C than did Dexsol-stored corneas. No significant differences were seen after 1 to 4 days at 26 degrees C. Temperature-reversal analysis showed no significant change in corneal thickness with warming after 2-week storage at 4 degrees C in either medium, although Optisol-stored corneas were significantly thinner than those stored in Dexsol at all times. The results of scanning electron microscopy suggest that preservation at refrigerator temperature for 2 weeks in Optisol is superior to preservation in Dexsol. Both media may be useful in preserving endothelial structure for limited periods at room temperature, which could provide a measure of safety in shipping or storage where refrigeration is unreliable.

Flow cytometry measurements of the DNA content of corneal epithelial cells during wound healing.

This study presents the first application of flow cytometry (FCM) techniques to the assessment of cell cycle dynamics in the corneal epithelium after experimental wounding. Anterior keratectomies 6 mm in diameter were created in the central corneas of albino rabbits. The authors sampled the epithelial tissue obtained outside the wound at 12-hr intervals until wound closure at 72 hr. Regenerated epithelium from the surface of the wounded area was collected at 78 hr. The percentages of nuclei in the G0/G1 (growth), S (DNA synthesis), and G2/M (tetraploid/mitosis) phases were determined by FCM. An increase in the percentage of nuclei in the G2/M phase at 36 hr was seen, compared with cell populations in samples from unwounded control corneas. The authors found an increase in mitotic activity in the corneal epithelium during the period of cell migration before wound closure.

Corneal allograft rejection following immunization.

Five patients developed corneal allograft rejection after immunization. One patient, a 33-year-old woman, received a tetanus toxoid booster nine months after a corneal transplant for keratoconus. Within four days she developed a graft rejection that required a penetrating keratoplasty two years later. Six months later, after hepatitis B immunization, the patient reported decreased vision and the graft was cloudy, but visual acuity was 20/20. The other four patients developed graft rejection after influenza immunization. Two of these four graft rejection episodes were successfully treated with high-dose corticosteroid therapy; all episodes occurred within several weeks of influenza immunization. Patients should be prudently counseled regarding the possible risks of immunization to corneal allograft survival.