Thomas E. Clinch

Microbial keratitis in children

In a five-year review, we identified 29 cases of microbial infection in 28 patients who were 16 years old or younger. Herpes simplex infections were excluded. Predisposing factors included trauma (ten cases, 34%), severe systemic illness (eight cases, 27%), contact lens use (seven cases, 24%), exposure keratopathy (seven cases, 24%), and previous ocular surgery (six cases, 21%). A total of 24 microorganisms were identified in cultures of corneal scrapings from 22 of the 29 cases; two cases involved polymicrobial infections. Of the 24 identified pathogens, gram-positive cocci were the most common (12). Other microorganisms included gram-negative bacteria (five) and fungi (four). Isolated cases of Acanthamoeba species, Borrelia burgdorferi, and Bacillus species were also present. Therapy with intensive topical antibiotics was successful in this series. The rate of surgical intervention (6/29, 21%) was similar to that of previous reports.

Anti-Interleukin-6 Antibodies Inhibit Herpes Simplex Virus Reactivation

Herpes simplex viruses (HSVs) infect epithelial cells, become localized in neurons, and can reactivate in response to a variety of stimuli, including ultraviolet light and hyperthermia. The sequence of gene activation during viral replication is known, but the molecular linkage between exogenous stimuli and HSV reactivation has not been determined. It was hypothesized that interleukin (IL)-6 acts as a signal between exogenous stimuli and neurons, stimulating HSV reactivation from latency. Mouse corneas were infected with HSV-1, and ocular reactivation was induced 5-7 weeks later by thermal stress or corneal exposure to ultraviolet light. Anti-IL-6 monoclonal antibodies were administered to the latently infected mice 8-12 h before the reactivation stimulus. Treatment with anti-IL-6 antibodies resulted in significantly lower frequencies of ocular reactivation compared with those in mice treated with a control immunoglobulin. These results support the hypothesis that IL-6 plays a role in HSV reactivation from latency.

Treatment of Contact Lens-related Ocular Surface Disorders with Autologous Conjunctival Transplantation

The authors describe two cases of chronic ocular surface disorder caused by the use of soft contact lenses. These cases demonstrated persistent corneal epithelial abnormalities, indolent ulceration, superficial stromal scarring, peripheral vascularization, and decreased visual acuity (worse than 20/400). Both cases were refractory to medical management, including discontinuation of contact lenses and topical medications. Autologous conjunctival transplantation restored the ocular surface with the return of good visual acuity (better than 20/40). Tissue culture demonstrated a decreased replication rate in the limbal epithelial cells, which suggests that epithelial stem cell dysfunction may be responsible for this ocular surface disease.

Chondroitin Sulfate: A New and Effective Protective Agent for Intraocular Lens Insertion

Chondroitin sulfate (CDS) has been found to serve as an excellent protective coating for intraocular lens (IOL) implantation to avoid any damage to the corneal endothelium; the protection is total. Using a new vital dye, acid violet 49, as a stain, a series of possible coatings including albumin and hyaluronic acid was evaluated in vitro and in vivo. Some 600 animal corneas were trephined, and the sample buttons submitted to the dragging of variously coated lenses across the endothelium. The animal species were rabbit, pig, cow, dog, cat, and monkey. IOLs were traumatically inserted in rabbits and monkeys. Chondroitin sulfate surpassed by far the protective qualities of other compounds: albumin was second best; hyaluronic acid third, the latter two yielding substantial damage in our tests. Comparisons with the commercially available Healon still revealed chondroitin sulfate to be the most efficacious protective agent. The material was eliminated from the anterior chamber in periods less than 40 hours. Monitoring of postoperative intraocular pressures revealed only normal pressures in our animals.

Efficacy of tobramycin drops applied to collagen shields for experimental staphylococcal keratitis

Treatment of staphylococcal keratitis includes tobramycin drops at repeated intervals, a prolonged therapy that is disruptive to the patient. To identify a regimen involving less frequent drug application, we compared the efficacy of fortified tobramycin (1.36%) administered by collagen shields or in topical drop form to rabbit corneas intrastromally infected with staphylococci. Eyes were treated with shields hydrated in and supplemented with fortified tobramycin drops (1.36%) applied every 1, 2, 5, or 10 h, from 10 to 20 h postinfection. For topical drop treatment alone, tobramycin was applied following the identical regimen. Untreated corneas contained 10(6) colony forming units. Shields supplemented with tobramycin drops applied every 1, 2, or 5 h sterilized 100% of the corneas. Shields supplemented with tobramycin drops applied at 10 h sterilized 58% of the corneas. Topical delivery of tobramycin every h sterilized all corneas; drops alone applied at longer intervals, such as 2, 5, or 10 h, sterilized 83%, 17%, and 0% of the corneas, respectively. Collagen shield delivery of tobramycin with supplemental topical drops can eradicate staphylococci in this model with less frequent dosing intervals than are required with topical therapy alone.

Fungal keratitis from nylon line lawn trimmers.

Ocular trauma from nylon line lawn trimmers is becoming more prevalent. Previous case reports have described penetrating trauma caused by these tools. We managed three cases of fungal keratitis caused by injuries from nylon line trimmers. Fungal keratitis should be strongly considered as the cause of any corneal ulcer related to trauma from a nylon line lawn trimmer.

Results of late flap removal after complicated laser in situ keratomileusis

Purpose: To evaluate the effect of flap removal on complications after laser in situ keratomileusis (LASIK). Setting: Three university‐based referral centers and 1 private practice. Methods: This retrospective interventional case series comprised 6 eyes of 6 patients at 4 centers. Flap removal occurred 2 to 41 weeks after the LASIK procedure. The corneal flaps were excised by 2 methods: In 2 eyes, the flap was lifted and excised manually. In 4 eyes, the thin flap was removed by excimer ablation using phototherapeutic keratectomy and/or photorefractive keratectomy. Postoperative measurements included uncorrected visual acuity, best spectacle‐corrected visual acuity (BSCVA), manifest refraction, slitlamp evaluation, and computerized videokeratography. All patients had an 8‐month or longer convalescence to assess visual recovery. Results: After the initial flap complication, the BSCVA decreased in all 6 eyes (mean loss 3.0 lines ± 1.5 [SD]). After flap removal, it improved in all eyes (mean gain 2.2 ± 1.2 lines). All patients reported a reduction in or elimination of visual symptoms. Despite the improvements, a minor loss of BSCVA (mean −0.8 lines [range 0 to 2 lines]) remained in 4 patients. Conclusion: In carefully selected patients, flap removal is a viable surgical option to improve visual function.