Tegument-specific, virus-reactive CD4 T cells localize to the cornea in herpes simplex virus interstitial keratitis in humans.

Herpes stromal keratitis (HSK) is a prevalent and frequently vision-threatening disease associated with herpes simplex virus type 1 (HSV-1) infection. In mice, HSK progression occurs after viral clearance and requires T cells and neutrophils. One model implicates Th1-like CD4 T cells with cross-reactivity between the HSV-1 protein UL6 and a corneal autoantigen. HSK can be prevented by establishing specific immunological tolerance. However, HSK can also occur in T-cell receptor-transgenic X SCID mice lacking HSV-specific T cells. To study the pathogenesis of HSK in the natural host species, we measured local HSV-specific T-cell responses in HSK corneas removed at transplant surgery (n = 5) or control corneas (n = 2). HSV-1 DNA was detected by PCR in two specimens. HSV-specific CD4 T cells were enriched in three of the five HSK specimens and were not detectable in the control specimens. Reactivity with peptide epitopes within the tegument proteins UL21 and UL49 was documented. Responses to HSV-1 UL6 were not detected. Diverse HLA DR and DP alleles restricted these local responses. Most clones secreted gamma interferon, but not interleukin-5, in response to antigen. HSV-specific CD8 cells were also recovered. Some clones had cytotoxic-T-lymphocyte activity. The diverse specificities and HLA-restricting alleles of local virus-specific T cells in HSK are consistent with their contribution to HSK by a proinflammatory effect.

Delayed onset keratectasia following laser in situ keratomileusis.

We present a case of unilateral iatrogenic keratectasia developing 10 months after bilateral laser in situ keratomileusis (LASIK) involving enhancement surgery using a broad-beam excimer laser (Summit Apex) to treat 6.6 diopters (D) of myopia. The ectasia progressed rapidly over the subsequent 12 months. The surgeon did not measure preoperative pachymetry, but preoperative topography and corneal measurements did not reveal underlying keratoconus or forme fruste keratoconus. Corneal transplantation was required for final visual rehabilitation. Light microscopy of the button revealed no underlying inflammation, which suggests biomechanical corneal weakening as the cause of the ectasia. Scanning electron microscopy showed the dramatic thinning seen clinically. latrogenic keratectasia appears to be a possible complication of LASIK.

Results one year after using the 193-nm excimer laser for photorefractive keratectomy in mild to moderate myopia.

As part of a clinical trial, photorefractive keratectomy using the VISX 2015 193-nm excimer laser was performed on 91 healthy eyes of 91 patients. Preoperative refractive errors (spherical equivalent) ranged from -1.00 to -7.50 diopters (mean, -4.16 +/- 1.41 diopters). No patient had more than 1 diopter of refractive astigmatism. Six months postoperatively, the average residual refractive error was +0.09 +/- 0.63 diopters (range, -2.13 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity of 20/40 or better was attained in 86 eyes (95%) and was 20/25 or better in 67 eyes (74%). At one year, follow-up information was available on 85 eyes of 85 patients. The average residual refractive error was -0.15 +/- 0.65 diopters (range, -2.50 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity was 20/40 or better in 83 eyes (98%) and was 20/25 or better in 68 eyes (80%). One patient lost three lines of best-corrected visual acuity because of corneal haze, dropping from 20/15 to 20/30, whereas all other patients returned to best-corrected visual acuity within one line of their preoperative best-corrected visual acuity. Photorefractive keratectomy with the 193-nm excimer laser appears to be a useful treatment modality for the reduction of mild to moderate myopia.

Use of the 193 nm excimer laser for photorefractive keratectomy in low to moderate myopia.

As part of a Phase III clinical trial, photorefractive keratectomy using the VISX 2015 193 nm excimer laser was performed on 91 sighted eyes of 91 patients. Preoperative refractive errors (spherical equivalent) ranged from -1.00 diopters (D) to -7.50 D (mean -4.11 D +/- 1.43 D). At six months, average residual refractive error was 0.02 D +/- 0.64 D (range -2.21 D to +1.38 D). Ninety-three percent of eyes were within 1.00 D of attempted correction, 93% had uncorrected visual acuity of 20/40 or better, and 72% achieved uncorrected visual acuity of 20/25 or better. All patients returned to their best corrected visual acuity within one line of their preoperative best corrected visual acuity. Photorefractive keratectomy with the 193 nm excimer laser appears to be useful in reducing low to moderate myopia.

Comparative diagnosis of neonatal chlamydial conjunctivitis by polymerase chain reaction and McCoy cell culture.

Cervical and ocular swabs from 100 mother/newborn pairs delivering on the clinic service were assayed for Chlamydia trachomatis with standard McCoy cell culture and with standard and biotinylated polymerase chain reaction techniques, using primers directed against the major outer membrane protein gene and C. trachomatis-specific cryptic plasmid, respectively. Using the polymerase chain reaction, 20 (20%) mothers and seven (7%) neonates were positive for Chlamydia. All neonates positive by polymerase chain reaction were from mothers positive by polymerase chain reaction, yielding a 35% transmission rate. Only five of 20 (25%) mothers and two of seven (28%) neonates positive by polymerase chain reaction were positive by cell culture. All cell culture samples were positive by polymerase chain reaction testing. Culture and polymerase chain reaction analysis two weeks after treatment with oral erythromycin were negative. The polymerase chain reaction assay appears to be equally specific and more sensitive than McCoy cell culture for the detection of C. trachomatis from ocular specimens.

The use of polymerase chain reaction for the detection of chlamydial keratoconjunctivitis.

Ocular swabs from 30 consecutive patients with follicular conjunctivitis were screened for Chlamydia trachomatis, herpes simplex virus, and adenovirus by a variety of laboratory techniques. For the detection of C. trachomatis, we compared two polymerase chain reaction methods, McCoy cell culture isolation, and the direct fluorescein-conjugated monoclonal antibody test. Four of 30 patients tested positive for C. trachomatis by using both conventional and biotinylated polymerase chain reaction methods. Two of the four patients were also McCoy cell culture-positive for C. trachomatis and one of four patients tested positive by using a fluorescein-conjugated chlamydial monoclonal antibody test. All four patients responded to oral antibiotic treatment. On follow-up testing, all four patients were polymerase chain reaction-negative, McCoy cell culture-negative, and fluorescein-conjugated antibody test-negative for C. trachomatis. The polymerase chain reaction appears to be an equally specific and more sensitive method than McCoy cell culture or fluorescein-conjugated antibody testing for the detection of C. trachomatis from ocular specimens.

Serious complications of topical mitomycin-C after pterygium surgery.

BACKGROUND: The use of topical mitomycin (mitomycin-C) as a medical adjunct to pterygium and glaucoma surgery is increasing. METHODS: The authors report on a series of 10 patients who experienced serious, vision-threatening complications associated with the use of this drug after pterygium surgery. RESULTS: Complications included severe secondary glaucoma (4 patients), corneal edema (3 patients), corneal perforation (1 patient), corectopia (2 patients), iritis (8 patients), sudden onset mature cataract (2 patients), scleral calcification (1 patient) and incapacitating photophobia and pain (8 patients). Two patients required penetrating keratoplasties and a third required three lamellar keratoplasties. Another patient underwent four additional surgeries including a conjunctival Z-plasty, scleral patch grafting, and conjunctival autografting before his intractable pain and photophobia resolved 15 months after the original surgery. Because of these complications, 6 patients required a total of 20 return visits to the operating room after their original pterygium surgery. In 5 eyes, visual acuity remained at 20/200 or less. Three of the six patients with the most severe complications had concomitant chronic external diseases (rosacea [3 patients], ichthyosis [1 patient], keratitis sicca [1 patient]). CONCLUSION: The authors urge extreme caution in the use of mitomycin. If mitomycin is used, the lowest possible concentration should be applied for the shortest time period in an effort to avoid these complications. A prospective multicenter study of the ophthalmic use of this medication is needed.

The relationship of retrobulbar hematomas to vision in cynomolgus monkeys.

An experimental model has been developed to measure the effect of retrobulbar hematomas on functional vision in cynomolgus monkeys. In this model, functional vision was quantitated using flashed evoked visual potentials in five monkeys following creation of retrobulbar hematomas. In one monkey used as a control, functional vision remained impaired for 180 minutes following induction of retinal ischemia by increased intraorbital pressure. In two monkeys in which increased intraorbital pressure was relieved by anterior chamber paracentesis following 15 minutes of retinal ischemia, flashed evoked visual potential promptly returned to baseline level. In two additional monkeys in which increased intraorbital pressure was relieved following 30 minutes of retinal ischemia, flashed evoked visual potentials improved but never returned to baseline levels. This study demonstrates the usefulness of flashed evoked visual potentials in measuring functional vision in cynomolgus monkeys. This experimental model should prove useful in evaluating the effects of increased intraorbital pressure on functional vision and the effect of intervention on impaired vision due to retrobulbar hematomas. Further studies with larger numbers of animals are needed to clarify these preliminary studies and document longer-term effects of retinal ischemia secondary to retrobulbar hematomas.

Effect of anterior chamber paracentesis on decreased retinal circulation due to retrobulbar hematoma in dogs.

An experimental canine model for blindness following blepharoplasty was developed to demonstrate occlusion of retinal circulation resulting from simulated retrobulbar hematoma. Seven mongrel dogs were studied, monitoring retinal vascular patterns by funduscopic examination and intraocular pressure by pneumotonometry. Anterior chamber paracentesis was performed in five dogs 10 minutes after injecting blood retrobulbarly, with an immediate decrease in pressure and return of retinal blood flow. In two dogs without paracentesis, increased pressure and blindness persisted. Anterior chamber paracentesis has been shown to reduce intraocular pressure from hematoma of the retro-orbital area in dogs. Although controversial, anterior chamber paracentesis may represent a useful temporizing adjunct in the treatment of increased intraocular pressure and impaired vision from hematoma following blepharoplasty.

The role of vitrectomy in the treatment of postoperative bacterial endophthalmitis. An experimental study.

While the diagnostic value of vitreous culture in the management of bacterial endophthalmitis is well established, the therapeutic value of vitrectomy in this condition is debated. The present experimental study uses an aphakic model of Staphylococcus aureus endophthalmitis in the rabbit. Animals were treated with the following: (1) intravitreal antibiotics alone; (2) intravitreal antibiotics with vitrectomy; (3) vitrectomy alone; and (4) no treatment. Eyes treated with antibiotics and vitrectomy displayed significantly clearer media at 14 days after therapy compared with eyes treated with antibiotics alone. There was also a greater tendency for eyes treated with antibiotics and vitrectomy to have negative cultures at 14 days, although this difference was not statistically significant. These findings are consistent with beneficial effects of therapeutic vitrectomy as an adjunct to intravitreal antibiotic therapy in an animal model of aphakic bacterial endophthalmitis.