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Biomedical subjects

T H Pettit

Publications and source records attributed to T H Pettit.

At least 19 recordsLinked to original sources
PubMed1997

Epibulbar hemangiopericytoma.

PURPOSE: To report a case of an epibulbar hemangiopericytoma that appeared clinically as a firm nodule. METHODS: We examined a 28-year-old man with a 5-year history of a gradually enlarging red, firm epibulbar nodule. Excisional biopsy was performed. RESULTS: Histopathology identified an encapsulated hemangiopericytoma. Eight-year follow-up showed no recurrence postresection. CONCLUSIONS: Epibulbar hemangiopericytoma is rare and has a good prognosis after resection. The smaller size and more conspicuous location of epibulbar hemangiopericytomas may lead to relatively early treatment and account for a more favorable prognosis.

Adult↗
PubMed1992

Reliability coefficients of three corneal pachymeters.

We compared the accuracy and reproducibility of a hand-held portable ultrasound pachymeter, the Pach-Pen (Bio-Rad, Ophthalmic Division, Santa Ana, California); another ultrasound pachymeter, the DGH 1000 (DGH Technology, Inc., Frazer, Pennsylvania); and the Pro-Cem 4 endothelial specular microscope (Alcon-Surgical, Inc., Irvine, California). Each eye of 18 healthy human subjects was examined to determine corneal thickness using the three different instruments. For each instrument, five repeated measurements were obtained at each of five corneal locations (one central, four peripheral), for a total of 25 measurements per eye. The accuracy of the two ultrasound pachymeters was tested by comparing measurements obtained on specially designed test blocks of known thickness. The Pach-Pen was the more accurate of the two ultrasound pachymeters, with measurements within the range of 0.003 to 0.065 mm from the true thickness. The three instruments were most consistent in mean thickness in the center of the cornea. All three instruments showed excellent intraobserver reproducibility, as measured by reliability coefficients over 90%. Overall, the Pach-Pen pachymeter had high reproducibility, and produced more accurate measurements than the DGH 1000 pachymeter.

Adult↗
PubMed1992

Results of inpatient and outpatient cataract surgery. A historical cohort comparison.

PURPOSE: The transition from inpatient to outpatient cataract surgery during the last decade was not accompanied by prospective investigation of its effect on visual outcomes or surgical complications. The authors performed this study to assess the impact of this transition on surgical results. METHODS: The authors reviewed 600 extracapsular cataract extractions performed by 4 experienced ophthalmic surgeons during a 36-month period; in 300 cases, patients were hospitalized after surgery (inpatient group), and, in 300 cases, patients were never hospitalized (outpatient group). The same surgical techniques were used in all cases. Visual outcome and rates for operative and postoperative complications were compared. RESULTS: There were no statistically significant differences between the inpatient and outpatient groups for visual acuity. Excluding patients with pre-existing nonlenticular ocular disease, a best-corrected visual acuity of 20/40 or better was achieved in 93.1% of inpatient cases and in 97.2% of outpatient cases 6 months after surgery. Postoperative, clinically apparent cystoid macular edema was more common in the inpatient group (P = 0.03); however, after exclusion of patients with diabetes, hypertension, age younger than 65 years, and eyes with pre-existing nonlenticular disease, there was no statistically significant difference between groups. No significant differences in rates for other operative and postoperative complications were identified, including wound dehiscence, unplanned postoperative filtering blebs, infectious endophthalmitis, retinal detachment, persistent iridocyclitis, glaucoma, and corneal edema. CONCLUSION: This study does not demonstrate that the transition to outpatient cataract extractions has had an adverse effect on surgical outcomes.

Aged↗
PubMed1991

Macroscopic pigmentation in a dematiaceous fungal keratitis.

The diagnosis of fungal keratitis can be difficult and is often delayed. The distinction between moniliaceous and dematiaceous (pigmented) keratomycoses is not commonly possible on clinical examination. We report a case of a Curvularia lunata fungal keratitis in a 40-year-old patient who presented with diffuse brown pigmentation throughout the ulcer bed. Histologic staining and growth on Sabourad's dextrose agar demonstrated the brown pigmentation characteristic of this pigmented fungus. We call attention to this clinical pigmentation as a helpful clue in the detection of dematiaceous fungal keratitis.

Adult↗
PubMed1990

Intraocular pressure measurement with the Tono-Pen through soft contact lenses.

We evaluated a miniaturized digital and electronic tonometer, the Tono-Pen, for accuracy of intraocular pressure measurement in the presence of a contact lens. In the manometric study, the Tono-Pen was used to measure a known intraocular pressure, ranging from 10 mm Hg to 60 mm Hg in a cadaver eye over soft contact lenses with different powers and a plano-T bandage lens. There was significant bias in pressure measurement over all contact lenses except for the plano-T, which had no bias at any level. In the clinical study, the intraocular pressures of 40 eyes in 20 normal patients were measured with and without a plano-T contact lens in place. Analysis of variance showed no significant interactive effect between the right and left eyes, with or without the lens. There was no significant difference in the Tono-Pen measurement of intraocular pressure over a plano-T contact lens compared with no lens.

Analysis of Variance↗
PubMed1989

Four cases of keratoconus and posterior polymorphous corneal dystrophy.

We examined four young men with keratoconus and posterior polymorphous corneal dystrophy. All four patients showed central corneal steepening and irregularity, and large areas of irregular polymorphous opacification at the level of Descemet's membrane (in at least one cornea of each patient), which are consistent with posterior polymorphous dystrophy.

Adult↗
PubMed1988

Mycobacterium fortuitum keratitis.

Two of four cases of Mycobacterium fortuitum keratitis occurred after corneal surgery with contact lens wear, one was associated with extended contact lens wear alone, and one occurred after a foreign body injury. All cases were characterized by pain, conjunctival hyperemia, stromal inflammation, and ulceration. Diagnosis was made by culture and acid-fast staining of corneal scrapings. On the basis of published experience with amikacin for the treatment of nonocular M. fortuitum infections, three patients were treated with topical amikacin. Two patients responded clinically, but histopathologic examination of a penetrating keratoplasty specimen in one of the two disclosed persistent infection. One patient was cured of early disease by debridement alone. Rapid diagnosis and absence of corticosteroid use were the two most important determinants of successful therapy. In advanced cases, infection may be cured and useful vision restored by penetrating keratoplasty.

Adult↗
PubMed1988

The Tono-Pen. A manometric and clinical study.

A new miniaturized, digital, electronic tonometer, the Tono-Pen (Intermedics, Pasadena, Calif), was evaluated for accuracy and reproducibility of results in the laboratory using enucleated human eyes with an indwelling pressure transducer (manometric study) and clinically using 100 eyes in 50 patients with normal corneas. Reproducibility was good in both the manometric study (SD = 1.09) and in the clinical study (SD = 1.21). Reproducibility of results was similar to that of the MacKay-Marg tonometer and the pneumotonometer in the manometric study, but less than that of the Goldmann applanation tonometer and the pneumotonometer in the clinical study. In the manometric study, the Tono-Pen had less mean error at high pressure ranges than either the MacKay-Marg tonometer or the pneumotonometer. In the clinical study, no statistically significant difference was found between the Tono-Pen and the applanation tonometer at pressures of 10 to 35 mm Hg (the extent of the data spread). In addition to being reliable and accurate, this miniaturized tonometer is portable and easy to use.

Glaucoma↗
PubMed1987

Traumatic wound dehiscence after penetrating keratoplasty.

Between 1980 and 1986, 14 of our patients had traumatic globe ruptures three days to 13 years after penetrating keratoplasty. There were eight men and six women, ranging in age from 29 to 82 years (average, 62 years). All ruptures occurred at the corneal donor-host interface. Eleven wound separations occurred with corneal sutures in place. Three of five patients who wore protective eyewear at the time of injury had final visual acuity of 20/200 or less. Final visual acuity was better than 20/200 in only seven patients. The force of the blunt trauma was the most significant factor in visual outcome. Ultimate causes of visual failure included posterior segment damage and intractable glaucoma.

Adult↗
PubMed1986

Corneal ulcers associated with daily-wear and extended-wear contact lenses.

Over a 21-month period, we treated corneal ulcers in 11 patients using daily-wear contact lenses and 29 patients using extended-wear contact lenses. Since more patients use daily-wear than extended-wear lenses, this suggests that patients using extended-wear lenses are at greater risk for the development of corneal ulcers. Positive bacterial cultures were obtained from the corneal scrapings of nine of 11 patients using daily-wear lenses and 20 of 29 patients using extended-wear lenses. In the daily-wear group, all 11 patients failed to exercise satisfactory care in using and disinfecting their contact lenses: three did not wash their hands before manipulating the contact lenses, eight wore them overnight, two did not use any disinfecting system, and four had contaminated contact lens cases, solutions, or drops. In the extended-wear group, 17 patients failed to exercise satisfactory care in using and disinfecting their contact lenses: 12 had contaminated contact lens care systems, two did not use any disinfection system, five reported not washing their hands before contact lens manipulation, and two disinfected their contact lenses at intervals of more than a month. We were unable to identify any defect in the way 12 patients took care of their extended-wear lenses, suggesting that there may be a problem with these contact lenses even when care is satisfactory.

Adult↗
PubMed1986

Cataract surgery after expulsive choroidal hemorrhage in the fellow eye.

Expulsive choroidal hemorrhage (ECH) is a dramatic and serious complication of cataract surgery that occurred in four of 8,285 consecutive cataract operations performed at the Jules Stein Eye Institute from 1970 to 1983, an incidence of 0.05%. This report reviews six patients who had uncomplicated cataract surgery after an expulsive choroidal hemorrhage occurred during cataract operation in the fellow eye. Factors predisposing to ECH are considered, and recommendations to minimize the risk of this complication during preoperative, operative, and postoperative periods are presented.

Adult↗
PubMed1985

Loading doses and extended dosing intervals in topical gentamicin therapy.

Loading doses and extended dosing intervals were studied in a rabbit model using topically applied gentamicin in a concentration of 13.6 mg/ml. Loading doses consisting of one drop every minute for five minutes produced significantly higher gentamicin concentrations in the cornea during the early hours of treatment than regimens using one drop every hour and one drop every 30 minutes. Extended dosing intervals of two and four hours, when used in conjunction with an initial loading dose, produced peak gentamicin levels above 125 micrograms/g of cornea. However, trough levels with these extended dosing intervals were significantly lower than troughs during hourly gentamicin administration. An extended dosing interval regimen consisting of three drops every two hours maintained peak and trough levels equal to those produced by one drop an hour.

Administration, Topical↗
PubMed1985

Composition of cellular infiltrates in rejected human corneal allografts.

We utilized the leu series of monoclonal antibodies and an indirect immunoperoxidase technique to quantitate the cellular infiltrates in seven rejected human corneal allografts and compared them to nine identically processed corneas from patients with chronic herpetic stromal keratitis and to three control corneas. The cellular infiltrates in the rejected allografts were of mixed composition, comprised predominantly of leu-1 positive T-lymphocytes and leu-M3 positive macrophages. Both helper and cytotoxic-suppressor T-cells were identified in the stromal lesions. Statistically significant differences were noted in the absolute number of mononuclear cells and macrophages seen infiltrating the rejected corneal allografts compared to the herpetic corneas. We discuss the implications of these findings with regard to possible mechanisms underlying corneal allograft rejection in man.

Adult↗
PubMed1985

Detection of HLA class I and II antigens in rejected human corneal allografts.

We compared the distribution of HLA-ABC (class I) and HLA-DR (class II) antigens on fresh human donor corneal tissue, donor corneas following a 72-hour storage in McCarey-Kaufman (M-K) medium, and corneal buttons from patients with allograft rejection and with chronic herpetic stromal keratitis. Incubation in M-K media had little or no effect on the distribution of HLA antigens as compared with fresh tissue. In contrast to control corneas, both HLA class I and II antigens were detected on corneal endothelial cells, cells in the stroma, and on basal epithelial cells in rejected allografts. Corneal endothelium in herpetic buttons did not express detectable HLA antigens. HLA-DR positive Langerhan's cells were demonstrated in the central corneal epithelium of rejected allografts, as well as in herpetic corneas, but not in control corneas except at the limbus. Based upon these observations, a theory of corneal allograft rejection in humans is proposed based upon the induction of class I HLA-ABC and class II HLA-DR antigens on cells in the donor button by a factor(s) associated with cellular inflammation.

Cornea↗
PubMed1985

Aging-related cataract: laboratory investigation and clinical management.

Cataract disrupts the crystalline lens, a transparent, elastic, avascular, biconvex structure composed of a capsule, lens epithelium, and lens fiber cells. Many factors contribute to the progression of lens opacity, but aging is most frequently associated with cataract. As aging-related cataract develops, many biochemical and biophysical changes occur, most notably a marked increase in the insolubilization of the crystallin and extensive oxidation damage to many of the lens constituents. Cataract management should include ophthalmologic history and examination, medical evaluation, optical correction, control of ocular and systemic disease that may contribute to cataract, discontinuation of cataractogenic drugs, and periodic reexamination. Surgery is indicated when cataract is associated with vision decrease interfering with activities important to the patient, intraocular inflammation or glaucoma, or interference with management of posterior segment disease. More than 600 000 cataract operations are done in the United States each year; in 1982 an estimated 496 000 cataract operations were combined with intraocular lens implantation.

Aged↗
PubMed1985

Neodymium: YAG laser posterior capsulotomy: the first 100 cases at UCLA.

Initial anatomic success was reported in 97 of the first 100 neodymium: YAG laser posterior capsulotomies performed at the Jules Stein Eye Institute. Visual acuity improved in 90 patients, was unchanged in five, and decreased in five. In the five patients with decreased visual acuity after posterior capsulotomy, the decrease was unrelated to capsulotomy and caused by progression of preexisting retinal disease. Our experience suggests that attention to patient evaluation and surgical technique can help minimize complications and assure best results.

Adolescent↗