Biomedical subjects

Jay S Pepose

Publications and source records attributed to Jay S Pepose.

25 records · Page 2Linked to original sources

PubMed2002

Astigmatic changes after excimer laser refractive surgery.

PURPOSE: To compare the astigmatic changes induced by spherical and elliptical excimer laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). SETTING: University-based refractive surgery practice. METHODS: Three-month refractive data from 317 eyes of consecutive patients having spherical PRK, astigmatic PRK (A-PRK), spherical LASIK, and astigmatic LASIK (A-LASIK) by a single surgeon (J.S.P.) using VISX 2020B and Star lasers over 2 years were studied for astigmatic changes resulting from the surgical procedure. RESULTS: At 3 months, the mean change in absolute astigmatism was +0.15 diopter (D) and -0.07 D in the spherical PRK and LASIK groups, respectively. Photorefractive keratectomy tended to induce with-the-rule (WTR) astigmatism, while LASIK was astigmatically neutral. As expected, the eyes treated with A-PRK and A-LASIK achieved a greater reduction in absolute astigmatism (-1.02 D and -1.28 D, respectively) than those treated with spherical PRK and LASIK. The qualitative nature of the astigmatic change was different between flap-based and PRK-based procedures. CONCLUSIONS: Spherical PRK is more likely than spherical LASIK to induce astigmatism, with a tendency toward WTR astigmatism. The eyes treated with spherical LASIK had no preponderant change in the direction of astigmatic magnitude or axis. Astigmatic PRK and LASIK effectively reduced astigmatism along the preoperative axis; A-LASIK tended to induce a random resultant axis in most patients.

Adult↗

PubMed2002

Confocal microscopic findings in a case of delayed-onset bilateral diffuse lamellar keratitis after laser in situ keratomileusis.

We report a case of bilateral diffuse lamellar keratitis (DLK) with delayed onset after a bilateral laser in situ keratomileusis (LASIK) procedure. A thorough history, review of systems, and laboratory evaluation revealed no pertinent medical history or risk factors for delayed-onset DLK after LASIK. Confocal microscopic examination of both corneas demonstrated a large number of activated keratocytes in the flap interface, particulate debris of variable size distributed throughout the interface, and scattered inflammatory cells. It was then decided to lift and wash both corneal flaps and interfaces. Scrapings for stains and cultures were also taken from both flap beds and were negative. After treatment with prednisolone acetate 1% and topical cyclosporin A 0.5%, the DLK resolved in both eyes with residual faint, diffuse, corneal haze. The patient developed a steroid-induced elevation in intraocular pressure that resolved after the topical corticosteroids were stopped.

Adult↗

PubMed2002

Therapeutic vaccination with vhs(-) herpes simplex virus reduces the severity of recurrent herpetic stromal keratitis in mice.

Virion host shutoff (vhs)-deficient herpes simplex virus (HSV) was tested as a therapeutic vaccine in a mouse model of UV light-induced recurrent herpetic stromal keratitis. Four weeks after primary corneal infection, mice were vaccinated intraperitoneally with vhs(-) vaccine or control. Four weeks after vaccination, the eyes of latently infected mice were UV-B irradiated to induce recurrent virus shedding and disease. Post-irradiation corneal opacity in latently infected, vhs(-)-vaccinated mice was significantly reduced compared to control-vaccinated mice (P=0.007 to 0.035). The incidence and duration of recurrent virus shedding were the same in both groups. Antibody titres were increased (P=0.05) and delayed type hypersensitive responses were unaffected by vhs(-) vaccination. Combined with studies using different vaccination timing and vhs(-) genotypes, these data suggest that deletion of vhs is a useful strategy in the development of a therapeutic HSV vaccine, and that temporal and genetic factors influence vaccination outcome.

Animals↗

PubMed2002

Therapeutic immunization with a virion host shutoff-defective, replication-incompetent herpes simplex virus type 1 strain limits recurrent herpetic ocular infection.

Immunization of mice with herpes simplex virus type 1 (HSV-1) mutant viruses containing deletions in the gene for virion host shutoff (vhs) protein diminishes primary and recurrent corneal infection with wild-type HSV-1. vhs mutant viruses are severely attenuated in vivo but establish latent infections in sensory neurons. A safer HSV-1 mutant vaccine strain, Delta41Delta29, has combined vhs and replication (ICP8-) deficits and protects BALB/c mice against primary corneal infection equivalent to a vhs- strain (BGS41). Here, we tested the hypothesis that Delta41Delta29 can protect as well as BGS41 in a therapeutic setting. Because immune response induction varies with the mouse and virus strains studied, we first determined the effect of prophylactic Delta41Delta29 vaccination on primary ocular infection of NIH inbred mice with HSV-1 McKrae, a model system used to evaluate therapeutic vaccines. In a dose-dependent fashion, prophylactic Delta41Delta29 vaccination decreased postchallenge tear film virus titers and ocular disease incidence and severity while eliciting high levels of HSV-specific antibodies. Adoptive transfer studies demonstrated a dominant role for immune serum and a lesser role for immune cells in mediating prophylactic protection. Therapeutically, vaccination with Delta41Delta29 effectively reduced the incidence of UV-B-induced recurrent virus shedding in latently infected mice. Therapeutic Delta41Delta29 and BGS41 vaccination decreased corneal opacity and delayed-type hypersensitivity responses while elevating antibody titers, compared to controls. These data indicate that replication is not a prerequisite for generation of therapeutic immunity by live HSV mutant virus vaccines and raise the possibility that genetically tailored replication-defective viruses may make effective and safe therapeutic vaccines.

Adoptive Transfer↗

PubMedDate not supplied

Late corneal scarring after photorefractive keratectomy concurrent with development of systemic lupus erythematosus.

PURPOSE: To report a case of late-onset corneal haze following previous photorefractive keratectomy (PRK) concurrent with the development of systemic lupus erythematosus. METHODS: Single case report and review of medical literature. RESULTS: A 41-year-old woman underwent uneventful bilateral, non-simultaneous photorefractive keratectomy (PRK) with retreatment of the right eye after 1 year. Two months after retreatment, the patient presented with headaches and mental status changes and was diagnosed with systemic lupus erythematosus. Severe reticular corneal scarring developed in the right eye 1 year after retreatment. After the patient's disease was well controlled on a maintenance dose of hydroxychloroquine 200 mg twice a day, mechanical debridement was performed on the right cornea with a marked decrease in corneal haze and improved best spectacle-corrected vision. CONCLUSION: Patients who manifest with autoimmune disorders such as systemic lupus erythematosus may be at greater risk for developing dense, reticular corneal scars after PRK.

Adult↗

PubMedDate not supplied

Proper positioning of the plume evacuator in the VISX Star3 excimer laser minimizes central island formation in patients undergoing laser in situ keratomileusis.

PURPOSE: To identify risk factors in a series of patients who developed steep central islands after laser in situ keratomileusis (LASIK). METHODS: We analyzed and compared the refractive and topographic outcome of a study group composed of 83 eyes of 44 patients who underwent LASIK using the VISX Star3 excimer laser with a refraction-matched control group of 83 eyes treated later. The vacuum aspirator of the excimer laser was abnormally positioned during the surgeries performed in the study group. RESULTS: Mean preoperative spherical equivalent refraction in the study group was -6.75 +/- 2.50 D. Four eyes with a mean preoperative spherical equivalent refraction of -9.27 +/- 2.29 D developed steep central islands. Thirty-three (38%) of 83 eyes treated needed retreatment for residual myopia or myopic astigmatism. In the control group, mean preoperative spherical equivalent refraction was -6.76 +/- 2.50 D. Ninety-three percent of eyes were within +/- 1.00 D of target refraction. Five (6.02%) of 83 eyes required retreatment and no eyes developed central islands. CONCLUSION: The abnormally positioned vacuum aspirator coupled with the higher preoperative refractive correction were the likely causative factors for central island formation and the increased incidence of undercorrection in these patients.

Astigmatism↗

PubMedDate not supplied

Factors predictive of LASIK flap thickness with the Hansatome zero compression microkeratome.

PURPOSE: To determine the explanatory power of preoperative variables and comeal flap thickness in laser in situ keratomileusis (LASIK) using the Hansatome zero compression microkeratome (Bausch & Lomb, Rochester, NY). METHODS: A prospective, nonrandomized, comparative interventional case study was performed on 250 eyes of 129 consecutive patients who underwent LASIK surgery using the Hansatome zero compression microkeratome. A 160-microm or 180-microm microkeratome head and an 8.5- or 9.5-mm suction ring were used in the procedures. Preoperative measurements included refraction, spherical equivalent, keratometry, intraocular pressure, corneal white-to-white, anterior chamber depth, and corneal eccentricity. Corneal thickness was measured intraoperatively using ultrasonic pachymetry before and after flap creation, and the difference was taken as flap thickness. Flap diameter was measured with a corneal gauge. Data were analyzed using simple, multiple, stepwise linear and non-linear regression analyses and two-tailed t tests. RESULTS: The mean flap thickness was 124 +/- 17 microm with the nominal 160-microm head and 142 +/- 20 microm with the nominal 180-microm head. One third (33%) of the total variation in flap thickness could be accounted for by three preoperative variables: average corneal thickness, spherical equivalent refraction, and choice of 160- or 180-microm microkeratome head. A simple correlation of 0.114 was noted between corneal eccentricity and flap thickness, but this variable did not add significant explanatory power on multiple regression analysis. Linear regression analysis allowed determination of a flap thickness nomogram with a standard error of the estimate of 16.9 microm and a 95% confidence interval of +/- 33.1. CONCLUSIONS: Comeal thickness is the most systematic predictor of corneal flap thickness using the Hansatome microkeratome. Because three preoperative variables account for only 33% of the range in flap thickness, future studies should focus on variations in blade extension and corneal biomechanical factors, which may also play an important role in determining flap thickness.

Adult↗