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Biomedical subjects

J C Erie

Publications and source records attributed to J C Erie.

18 recordsLinked to original sources
PubMed2001

Analysis of postoperative glare and intraocular lens design.

PURPOSE: To assess the potential for reflected glare images from commonly used intraocular lens (IOL) materials and designs. SETTING: Mayo Clinic, Rochester, Minnesota, USA. METHODS: The interaction of reflected light rays from 3 commonly used IOLs (Bausch & Lomb LI61U and P359UV; Alcon AcrySof(R) MA60BM) with different optic designs (equi-biconvex: 10.0 and 15.0 mm anterior radius of curvature; unequal biconvex: 32.0 mm anterior radius of curvature) and optic materials (silicone, poly[methyl methacrylate], and acrylic) were examined in an eye model using the Zemax optical design program. The potential of each IOL model to produce subjective glare was determined from the size of the defocused reflected glare image at the retina. RESULTS: The unequal biconvex design concentrated reflected light on a retinal area that was 60-fold smaller than that of the equi-biconvex design. Increasing the refractive index of the IOL material from 1.43 (silicone) to 1.55 (acrylic) increased the amount of reflected light 5-fold. Compared to an equi-biconvex design composed of a lower refractive index material, the unequal biconvex design with a higher refractive index material increased the relative intensity of reflected light at the retina 300-fold, and for eyes with low corneal power the intensity increased 3500-fold. Similarly, for external glare apparent to an outside observer, the intensity of reflected light increased 400-fold and for low corneal power it increased 6000-fold. CONCLUSION: An unequal biconvex IOL design (32.0 mm anterior radius of curvature) composed of a higher refractive index material increased the potential for postoperative glare and external reflections.

Computer Simulation↗
PubMed2000

Hearing loss and phacoemulsification.

PURPOSE: To determine the acoustic spectra of currently used phacoemulsification units and to contrast phacoemulsification-generated acoustic spectra with representative audiograms of common types of sensorineural hearing loss. SETTING: Mayo Clinic, Rochester, Minnesota, USA. METHODS: The acoustic spectra of 3 phacoemulsification systems (Alcon Series 20,000 Legacy, Storz Millennium, and AMO Diplomax) were recorded in an acoustically soundproofed room using a Roland VS-880 Digital Studio Workstation and analyzed with a Hewlett-Packard 35660A Dynamic Signal Analyzer. RESULTS: Phacoemulsification handpiece-generated harmonic overtones produced during ultrasound mode (6.0, 12.0, and 18.8 kHz for the 20,000 Legacy and Diplomax; 7.0 and 14.2 kHz for the Millennium) were outside the range of minimal decibel loss in individuals with hearing loss. Supplemental, low-frequency, console-generated tones produced during ultrasound mode (0.4 to 2.0 kHz for the Diplomax; 0. 1 to 1.5 kHz for the Millennium) were within the range of minimal decibel loss in individuals with hearing loss. CONCLUSION: Phacoemulsification systems with console-generated, low-frequency tones were audible to ophthalmologists with common types of sensorineural hearing loss.

Audiometry↗
PubMed1999

Retinal detachment in Olmsted County, Minnesota, 1976 through 1995.

OBJECTIVE: To estimate the incidence of rhegmatogenous retinal detachment (RD) in a geographically defined population and to compare the probability of RD in residents after cataract extraction with the probability of RD in residents who did not have cataract extraction. DESIGN: Rochester Epidemiology Project databases were used to perform a retrospective population-based incidence study of RD diagnosed between 1976 and 1995 with cohort analyses of the influence of risk factors on the occurrence of RD. PARTICIPANTS: The population of Olmsted County, Minnesota, participated. MAIN OUTCOME MEASURE: Incidence rates of RD adjusted to the age and gender distribution of the 1990 U.S. white population were measured. RESULTS: Three hundred eleven incident cases of rhegmatogenous RD were identified. The mean annual age- and gender-adjusted incidence rate of rhegmatogenous RD was 17.9 per 100,000 persons (95% confidence interval [CI], 15.9-19.9). For idiopathic rhegmatogenous RD alone, the mean annual age- and gender-adjusted incidence rate was 12.6 (95% CI, 10.9-14.3) per 100,000 persons. Ten years after phacoemulsification and extracapsular cataract extraction, the estimated cumulative probability of RD was 5.5 (95% CI, 3.4-7.6) times as high as would have been expected in a similar group of county residents not undergoing cataract surgery. CONCLUSIONS: Cataract surgery is associated with a significantly elevated long-term cumulative probability of retinal detachment.

Adolescent↗
PubMed1999

Keratocyte density in vivo after photorefractive keratectomy in humans.

PURPOSE: To determine changes in keratocyte density in central human corneas in vivo after photorefractive keratectomy (PRK). METHODS: Fifteen patients (25 eyes) received excimer PRK (VISX Star) with epithelial removal by laser-scrape (43 microns ablation followed by manual scrape) to correct myopia between -1.5 D and -7.25 D. Corneas were examined by using confocal microscopy in vivo before PRK and at 1 day, 5 days, 1 month, and 3 months after PRK. A custom automated image-processing algorithm identified bright objects (keratocytes) against a dark background and estimated keratocyte density by using the number and size of the objects. Cell density was quantified in anteroposterior stromal regions after PRK and compared to cell density in corresponding pre-PRK regions. RESULTS: One day after PRK, keratocyte density increased 9% in the anterior third of the stroma (pi = .003), was unchanged in the middle third of the stroma (pi = .481), and decreased 6% in the posterior third of the stroma (pi = .038). Keratocyte density remained elevated in the anterior stroma to 3 months after PRK; at this time, there was a 13% increase in keratocyte density throughout the full-thickness stroma (pi < .001). CONCLUSIONS: Keratocyte density was increased in the anterior stroma immediately after PRK in humans. Three months later, keratocyte density was increased in all anteroposterior stromal regions, suggesting that PRK affects keratocytes throughout the entire central cornea.

Adult↗
PubMed1998

Congenital esotropia in Olmsted County, Minnesota.

OBJECTIVE: To determine the birth prevalence of and risk factors associated with congenital esotropia. DESIGN: Population-based prevalence study with nested case-control study. PARTICIPANTS: All residents of Olmsted County, Minnesota who were diagnosed with congenital esotropia and born between January 1, 1980 and December 31, 1989 (n = 47). Control subjects were chosen by selecting the next two sequential births to parents residing in Olmsted County, Minnesota (n = 94). METHODS: Cases were identified through the Medical Diagnostic Index of Mayo and the Rochester Epidemiology Project. The community medical records were reviewed to confirm case status and ascertain risk factor information. MAIN OUTCOME MEASURE: Birth prevalence of congenital esotropia. RESULTS: Forty-seven cases were identified from 17,536 live births, for a birth prevalence of 27 per 10,000 (95% confidence interval [CI], 20-35). Congenital esotropia was associated with prematurity (odds ratio [OR], 11.5; 95% CI, 3.4-39.2), a birth weight less than 2500 grams (OR, 4.6; 95% CI, 1.7-12.9), a low Apgar score at 1 minute (OR, 4.3; 95% CI, 1.7-11.2) and at 5 minutes (OR, 6.3; 95% CI, 1.3-30.7), and a family history of strabismus (OR, 3.5; 95% CI, 1.5-8.3). CONCLUSIONS: The birth prevalence of congenital esotropia in Olmsted County, Minnesota is lower than previous estimates. Prematurity, low birth weight, low Apgar scores, and a family history of strabismus are significant risk factors for congenital esotropia.

Apgar Score↗
PubMed1998

Effect of intraocular lens design on neodymium:YAG laser capsulotomy rates.

PURPOSE: To compare the effect of 2 poly(methyl methacrylate) (PMMA), 1-piece biconvex intraocular lens (IOL) designs on the cumulative frequency of neodymium:YAG (Nd:YAG) laser posterior capsulotomy. SETTING: Department of Ophthamology, Mayo Clinic, Rochester, Minnesota, USA. METHODS: This retrospective study evaluated 369 eyes that had phacoemulsification with continuous curvilinear capsulorhexis (CCC) and IOL implantation in the capsular bag. Patients were placed in 1 of 2 groups based on the 1-piece, biconvex PMMA IOL design: large IOL, with a lens diameter of 13.50 to 13.75 mm, optic size of 6.5 mm, and 10 degree haptic angulation; small capsular IOL, with a lens diameter of 12.0 to 12.5 mm, optic size of 5.5 mm, and 2 degree haptic angulation. RESULTS: Using Kaplan-Meier analysis, the frequency of Nd:YAG laser posterior capsulotomy 1, 2, and 3 years after cataract surgery was 1.6, 12.3, and 26.5%, respectively, in the large IOL group and 3.4, 9.5, and 23.5%, respectively, in the small capsular IOL group. The cumulative frequency of Nd:YAG laser capsulotomy was not statistically different between the 2 groups. CONCLUSION: After phacoemulsification and CCC, there was no significant difference in the Nd:YAG laser capsulotomy rate in eyes with a small, capsular design, 1-piece, biconvex PMMA IOL and those with a larger, angulated, 1-piece, biconvex PMMA IOL.

Adolescent↗
PubMed1997

The incidence of primary angle-closure glaucoma in Olmsted County, Minnesota.

OBJECTIVES: To determine the incidence of primary angle-closure glaucoma (PACG) and to assess the visual outcomes of patients treated for PACG. DESIGN: Population-based retrospective incidence study. SETTING AND PATIENTS: Residents of Olmsted County, Minnesota, aged 40 years and older and diagnosed with PACG in the 13-year period between January 1, 1980, and December 31, 1992. MAIN OUTCOME MEASURE: Incident cases of PACG identified through the Medical Diagnostic Index of Mayo Clinic, Rochester, Minn, and the Rochester Epidemiology Project. RESULTS: Thirty-six incident cases were identified. The mean annual age-and sex-adjusted incidence per 100000 people aged 40 years and older was 8.3 (95% confidence interval, 5.6-11.0). The probability of monocular blindness associated with PACG at the time of diagnosis was 14%. Among patients not monocularly blind at diagnosis, the 5-year probability of developing monocular blindness associated with PACG was 4%. CONCLUSIONS: Primary angle-closure glaucoma is an uncommon disease in our community. Most of the patients blinded by PACG were blind at the time the condition was diagnosed.

Acute Disease↗
PubMed1995

Biochemical quantification of triamcinolone in subconjunctival depots.

OBJECTIVE: To biochemically quantify the amount of active triamcinolone acetonide remaining after subconjunctival administration and to assess the effectiveness of surgical management for glaucoma induced by triamcinolone. DESIGN: Case series. PARTICIPANTS: Seven eyes of seven patients whose ages ranged from 47 to 84 years underwent excision of depot triamcinolone. Six of seven eyes required surgical intervention for medically unresponsive intraocular pressure (IOP) elevation. RESULTS: Pharmacologically active triamcinolone was identified up to 13 months following injection (range, 3 to 13 months). The mean amount in the excised sample was 5.4 mg (range, 2.0 to 8.8 mg), and the mean percentage of the original sample remaining was 20% (range, 4.2% to 44%). Glaucoma was diagnosed a mean of 3 months after injection (range, 1 to 6 months). Mean IOP was 37 mm Hg before excision and 16 mm Hg after removal. Surgical excision of visible triamcinolone normalized IOP in six of seven patients without need for glaucoma medications. CONCLUSIONS: Periocular injection of triamcinolone necessitates careful monitoring of IOP. Medically unresponsive IOP elevation may occur as late as 6 months following periocular triamcinolone injection. Surgical excision of remaining triamcinolone depot is an effective therapy for IOP elevation. Guidelines for safely using triamcinolone are discussed.

Aged↗
PubMed1993

Incidence of ulcerative keratitis in a defined population from 1950 through 1988.

OBJECTIVE: To determine the incidence of ulcerative keratitis and to assess trends in risk factors leading to ulcerative keratitis. DESIGN: Retrospective incidence cohort study. SETTING: General community. PATIENTS: Population-based sample of residents of Olmsted County, Minnesota, in the 39-year period between 1950 and 1988. MAIN OUTCOME MEASURE: Cases of ulcerative keratitis. RESULTS: One hundred forty-one cases of ulcerative keratitis were diagnosed among 131 residents (64 men and 67 women) of Olmsted County. The mean annual age-adjusted incidence per 100,000 people was 5.3 (95% confidence interval, 4.4 to 6.2). A 435% increase in the incidence of ulcerative keratitis was observed in Olmsted County residents from the 1950s (2.5 per 100,000 people) to the 1980s (11.0 per 100,000 people) (P = .001). The cases of ulcerative keratitis associated with contact lens wear increased from 0% in the 1950s and 1960s to 32% in the 1970s and 52% in the 1980s. CONCLUSION: The incidence of ulcerative keratitis has increased significantly in this community. Contact lens wear was the most important risk factor for the development of ulcerative keratitis during the last decade.

Adolescent↗
PubMed1992

Incidence of enucleation in a defined population.

We conducted a population-based study of long-term trends in the incidence of enucleation. From 1956 through 1988, enucleation was performed on 99 residents (55 males and 44 females) of Olmsted County, Minnesota. The mean annual age-adjusted incidence per 100,000 population for males (5.17) was 50% greater than that for females (3.49; P = .04). An increase in the enucleation rate was noted with increasing age (P = .001), with the highest incidence in patients who were 70 to 79 years of age. A decrease in the incidence of enucleation over time (P = .002) was observed in Olmsted County residents who were at least 40 years of age and was caused primarily by the decreasing incidence of neovascular glaucoma and tumor-related enucleations. The incidence of traumatic enucleations did not significantly decrease (P = .25) over this three-decade study period.

Adolescent↗
PubMed1992

Computerized analysis of pupillograms in studies of alertness.

When alert subjects sit in a quiet, darkened room for 10-15 min, their pupils remain dilated. If the subjects become sleepy or fatigued, their pupils become miotic and oscillate. Pupillometry, the recording of pupil diameter, has been used to study alertness. Pupillograms are typically graded by subjective assessment on the basis of oscillations of pupil diameter (hippus) and miosis. In this study, numeric parameters were calculated from pupillograms and were compared to subjective ratings by clinicians. Pupil diameters were recorded for 15 min at five samples per second with a custom built video pupillometer. Subjects sat in the dark and fixated a small red light. Digital filtering techniques and Fourier analysis were used to calculate several parameters designed to report hippus and miosis. The same set of pupillograms was graded by three physicians familiar with pupillometry. Grades were assigned on a scale of 1 to 4, 1 being most alert and 4 least alert. A linear combination of three of the numeric parameters had the highest correlation with the average subjective grade (r = 0.92). These techniques provide a quantitative way to evaluate pupillograms that will be used in the assessment of alertness.

Adolescent↗
PubMed1990

Presumed small choroidal melanomas with serous macular detachments with and without surface laser photocoagulation treatment.

We reviewed the records of 22 patients (22 eyes) who had presumed small choroidal melanomas associated with a serous macular detachment. In 13 eyes, the tumor surface was treated with laser photocoagulation to reattach the retina and improve vision. After photocoagulation, the retina reattached in 11 eyes (85%), and the visual acuity improved in eight eyes (62%), returning to 20/25 or better in six eyes (46%). Twelve of the tumors (92%) that received surface photocoagulation grew after treatment. Seven of these tumors (54%) developed a collar-button configuration and showed evidence of basal expansion. Of the nine tumors that did not receive surface photocoagulation, seven (78%) eventually grew, but none developed a collar-button configuration. Surface photocoagulation applied to a growing melanoma appears to increase the likelihood of tumor extension through Bruch's membrane in a collar-button configuration. The impact of such growth on tumor metastasis is unknown.

Adult↗
PubMed1986

Serous detachments of the macula associated with presumed small choroidal melanomas.

Eight cases of presumed small choroidal melanomas, associated with subretinal fluid in the macula, were studied to determine the eventual outcome of these tumors and the value of photocoagulation in eliminating subretinal fluid. Photocoagulation resulted in resolution of subretinal fluid involving the macula in six cases for a mean duration of 12 months. Six cases showed tumor growth over a mean interval of 24 months. Two cases were eventually managed with enucleation and two with I125 brachytherapy. The occurrence of subretinal fluid involving the macula in cases of small choroidal melanomas implies a high chance of subsequent tumor growth. Photocoagulation may be useful in eliminating subretinal fluid and improving vision during this observation period.

Adult↗
PubMed1986

Conjunctival and corneal intraepithelial and invasive neoplasia.

The histopathologic findings and clinical records of 98 patients with conjunctival and corneal intraepithelial neoplasia (CIN) and 22 patients with invasive neoplasia were studied. Pathologic material was evaluated for cell type, degree of dysplasia, margins of excision, and change in pattern with recurrence. Clinical records were reviewed for demographic features, presenting symptoms, clinical appearance, therapy, and subsequent course. Recurrences occurred in 23 patients with CIN and 9 patients with invasive neoplasia. Intraocular or orbital extensions or both occurred in four patients and metastatic disease in two patients. The cell type, clinical appearance, and degree of dysplasia did not correlate with recurrence; involvement of the margins of the initial excision was an important prognostic sign for recurrence.

Adolescent↗