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Biomedical subjects

R J Olson

Publications and source records attributed to R J Olson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Prospective randomized comparison of phacoemulsification cataract surgery with a 3.2-mm vs a 5.5-mm sutureless incision.

PURPOSE: To report sutureless cataract surgery by phacoemulsification with a 3.2-mm surgical incision compared with a 5.5-mm surgical incision. METHOD: In a prospective, randomized, masked clinical trial of phacoemulsification cataract surgery, 55 eyes (55 patients) had a 3.2-mm incision and 56 eyes (56 patients) had a 5.5-mm incision. All incisions were in the superior vertical meridian, commenced 1.5 mm posterior to the limbus, and extended into the cornea for a total length of 2.5 to 3.0 mm. In a masked fashion, astigmatism was monitored by keratometry, and logMAR visual acuity was determined both with and without best correction throughout a mean follow-up of 33.9 months. RESULTS: Statistically significant differences were seen in favor of the 3.2-mm incision group at the final examination for astigmatism (Cravy analysis) and uncorrected visual acuity (-0.18 vs -0.88 diopter, P < .001; logMAR, 0.14 vs 0.26, P = .04). CONCLUSIONS: Over the long term, phacoemulsification with a 3.2-mm incision is associated with significantly less astigmatic shift and better uncorrected visual acuity than is phacoemulsification with a 5.5-mm incision. A small incision with a foldable intraocular lens has long-term benefits.

Aged↗
PubMed1998

Intraoperative crystallization on the intraocular lens surface.

PURPOSE: To report a physician survey, laboratory studies, and clinical observations of intraoperative crystallization on the surface of the intraocular lens (IOL). METHOD: We sent a survey to all ophthalmologists in the states of Wyoming, Idaho, Montana, Utah, and Colorado asking whether crystallization on the IOL surface had occurred in any of their patients and what viscoelastics, IOLs, and other solutions were used. All returned surveys were tabulated and analyzed by standard statistical means. A sample of crystallization from an IOL on a glass slide submitted by a physician was analyzed to ascertain the relative elemental composition. During in vitro laboratory studies, BSS Plus (Alcon Surgical, Fort Worth, Texas) and BSS (Alcon Surgical) were measured and analyzed for precipitation. Healon GV (Pharmacia/Upjohn, Kalamazoo, Michigan) and calcium chloride were combined in various solutions and examined for precipitate formation. Silicone IOLs and plate silicone were placed in different BSS and BSS Plus solutions with different viscoelastics and varying calcium concentrations. In seven patients, prominent crystallization on an IOL surface was examined, photographed, and followed for up to 3 years. RESULTS: Two hundred six surveyed ophthalmologists returned 181 surveys (88%) and reported 29,609 cataract surgeries, with IOL implantation with 22 eyes (0.07%) (22 patients) in which intraoperative crystallization was observed on the IOL surface during 1993. The survey indicated there was a correlation with BSS Plus (chi-square = 4.9, P = .0268) and silicone IOLs (chi-square = 6.8, P = .0093). The sample showed the cation to be calcium. CONCLUSION: Crystallization on the IOL surface during cataract surgery is a rare occurrence that may be associated with calcium as the cation related to an osmotic gradient around the IOL with increased calcium concentration. If encountered surgically, the lens should be exchanged in the operating theater after irrigating the anterior chamber with BSS and completely filling the capsular bag with a low molecular weight viscoelastic.

Aged↗
PubMed1998

Surgical outcomes of cataract extractions performed by residents using phacoemulsification.

PURPOSE: To assess whether changes in surgical technique, resident training, and phacoemulsification equipment affected the complication rate for cataract extractions performed by residents. SETTING: Combined urban and rural setting at a tertiary care academic center and a general care Veterans Administration Hospital, Salt Lake City, Utah, USA. METHODS: This retrospective study analyzed 396 patients who had cataract surgery by phacoemulsification and intraocular lens implantation performed by four residents. The residents' first 50 cases were compared with the last 50 cases performed at the end of their training. Surgical and 1 day postoperative complications were examined. RESULTS: Twenty of 396 surgical cases (5.1%) involved complications, and the overall vitreous loss rate for the four residents was 1.8%. A statistically significant difference was observed between the two residents with the highest and lowest number of intraoperative complications (P < .05) and between the two residents with the highest and lowest number of 1 day postoperative complications (P < .05). The rate of posterior capsule rupture with vitreous loss was 2.6% in the residents' early cases; the decrease to no cases of posterior capsule rupture in the late cases was also statistically significant (P < .02). CONCLUSION: The results indicate that with proper training and supervision, residents can obtain an acceptably low complication rate using phacoemulsification. As their skill increased, they were able to use phacoemulsification successfully on more complicated cases. Individual skill was also an important factor in the complication rate.

Clinical Competence↗
PubMed1998

In vitro analysis of AcrySof intraocular lens glistenings in AcryPak and Wagon Wheel packaging.

PURPOSE: To compare the formation of "glistenings" in acrylic intraocular lenses (IOLs) packaged in Wagon Wheel and AcryPak packaging systems. SETTING: John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Acrylic IOLs in Wagon Wheel (WW) and AcryPak (AP) packaging were analyzed in vitro. The lenses were placed in a test chamber with a controlled temperature and evaluated every 48 hours for 336 hours. The presence of glistenings within the lens optic was assessed using slitlamp evaluation and a quantitative microscopic evaluation with an image analysis system. RESULTS: When maintained at a constant temperature, the WW-packaged IOLs showed no glistening formation and the AP-packaged IOLs, significant glistening formation. Glistenings were noted in the WW-packaged IOLs only under fluctuating temperature conditions. Quantitative image analysis confirmed the presence of glistenings only in AP-packaged IOLs maintained at a constant temperature. CONCLUSION: The glistenings in AcrySof IOLs were temperature dependent and confined to IOLs packaged in AcryPak folders and maintained at constant (body) temperatures. These findings are believed to be consistent with fluid formation within the acrylic optic, somehow related to the AcryPak packaging system.

Acrylates↗
PubMed1998

Comparison of energy required for phaco-chop and divide and conquer phacoemulsification.

PURPOSE: To evaluate the safety and usefulness of phaco-chop cataract extraction. SETTING: A university-associated, multispecialty ophthalmology practice. METHODS: Fifty-three patients in a university-associated ophthalmology practice had cataract extraction, 32 by the phaco-chop technique and 21 by four-quadrant divide and conquer phacoemulsification. Phacoemulsification energy and complication rates were compared. RESULTS: Mean phacoemulsification energy was significantly lower in the phaco-chop group (mean 782 J +/- 446 [SD]) than in the divide and conquer group (mean 3264 +/- 1218 J)(P < .00001). No complications occurred in either group. CONCLUSION: The phaco-chop technique provided safe, effective cataract extraction with significantly less energy than that required for divide and conquer phacoemulsification.

Humans↗
PubMed1998

Dissociative phenomena in congenital monocular elevation deficiency.

INTRODUCTION: Monocular elevation deficiency is characterized by unilateral limitation of elevation in both adduction and abduction and is usually present at birth. Dissociative phenomena such as dissociated vertical deviation are well recognized in association with conditions such as congenital esotropia but much less so in association with conditions such as congenital monocular elevation deficiency. METHODS: All 129 patients given the diagnosis of monocular elevation deficiency or double elevator palsy in the Pediatric Ophthalmology and Strabismus Clinic at the University of Iowa Hospitals and Clinics between 1971 and 1995 were reviewed. After those with history of trauma, myasthenia gravis, thyroid eye disease, orbital lesions, Brown syndrome, or monocular elevation deficiency with acquired onset were excluded, 31 patients with congenital monocular elevation deficiency remained for retrospective study. RESULTS: First diagnosed at median age 2.6 years (although all were noted by parents at less than 6 months of age) with mean follow-up of 5.0 years (up to 15.5 years), 9 of 31 (29%) developed dissociated vertical deviation in the eye with monocular elevation deficiency, all of whom had undergone strabismus surgery 0 to 9.7 years previously (mean 3.5 years). Those who developed dissociated vertical deviation were generally younger, were followed up longer, and had more accompanying horizontal strabismus than did those who did not develop dissociated vertical deviation. The results did not reach significance. CONCLUSION: The current study demonstrates that dissociated vertical deviation occurs in association with monocular elevation deficiency.

Aging↗
PubMed1998

Ultradian Growth in Prochlorococcus spp.

Species of the widespread marine prokaryote Prochlorococcus exhibited ultradian growth (faster than 1 division per day) both in situ and in culture, even though cell division is strictly phased to the light-dark cycle. Under optimal conditions a second DNA replication and cell division closely followed, but did not overlap with, the first division. The timing of cell cycle events was not affected by light intensity or duration, suggesting control by a light-triggered timer or circadian clock rather than by completion of a light-dependent assimilation phase. This mode of ultradian growth has not been observed previously and poses new questions about the regulation of cellular rhythms in prokaryotes. In addition, it implies that conclusions regarding the lack of nutrient limitation of Prochlorococcus in the open ocean, which were based on the appearance that cells were growing at their maximal rate, need to be reconsidered.

Journal Article↗
PubMed1998

Silicone versus polymethylmethacrylate intraocular lenses with regard to capsular opacification.

BACKGROUND AND OBJECTIVE: The authors conducted a 3-year randomized trial to compare silicone intraocular lenses (IOLs) with polymethylmethacrylate (PMMA) IOLs, to determine any differences in laser capsulotomy rates, capsular opacification light scatter, and subjective scoring. PATIENTS AND METHODS: A total of 119 patients were enrolled, 84 of whom were examined at 3 years. The authors designed a prospective, masked, and randomized trial to compare the objective (lens opacity meter), subjective (slit-lamp scoring), and clinical parameters of the posterior capsular opacification (PCO) of these patients. RESULTS: The silicone group had less PCO than the PMMA group, according to objective (8.6% vs. 10.4%; P = .02, Student's t test) and subjective scoring (0.88 vs. 1.79; P = .0001, Student's t test). The laser capsulotomy rate was 24% for the silicone group and 33% for the PMMA group; however, this difference was not statistically significant. CONCLUSION: The silicone IOL was associated with less PCO than the PMMA IOL.

Aged↗
PubMed1997

In vitro evaluation of topical fluorides for overdenture abutments.

STATEMENT OF PROBLEM: Topical fluorides are effective, yet none have been developed specifically for root or dentin surfaces. PURPOSE: This study evaluated the ability of several commercial topical fluorides to protect overdenture abutments from in vitro acid demineralization. MATERIAL AND METHODS: Twenty extracted teeth from persons aged 50 to 70 years were prepared for overdenture abutments. The teeth were sectioned to provide 40 buccal and lingual halves, covered with nail varnish except for windows on the occlusal and root surfaces, and randomly divided into 4 groups of 10 specimens, which were cycled for 6 hours in acid demineralization, washed, and then held 17 hours in a remineralizing solution for 18 days. Before each cycle, the specimens were treated with either Karigel, Karigel-N, or a NaF solution. The control group was treated with fluoride-free solution. RESULTS: The depth of the artificial lesions on the root surfaces showed a statistically significant dose response. On the occlusal, there were no differences in lesion depth between the various topical fluorides and the control group. But there was a dose response when the remineralized band was subtracted from the lesion depth. Remineralization bands in the occlusal lesions were not evident in the control group, but were present in the fluoride groups. CONCLUSION: This study suggests that higher concentrations of NaF are more protective for overdenture abutments.

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PubMed1997

Ten-year experience in managing a capitated ophthalmology carve-out by an academic eye center.

A 10-year experience of managing a capitated opthalmology carve-out by an academic health unit is presented. Lessons learned regarding pricing, utilization, and managing this contract are discussed. Handling the cost of education and remaining competitive is presented as a not-insurmountable hurdle. Academic health units can compete in today's environment; however, the learning curve is steep and the problems many.

Academic Medical Centers↗
PubMed1997

Intraoperative miotics and posterior capsular opacification following phacoemulsification with intraocular lens insertion.

BACKGROUND AND OBJECTIVES: Posterior capsular opacification (PCO) is a frequent complication following phacoemulsification with intraocular lens (IOL) implantation. A series of consecutive patients receiving capsular bag-fixated, silicone IOL implants were assessed for both incidence of PCO and the administration of intraoperative miotics. PATIENTS AND METHODS: During a 5-year period, 477 consecutive eyes were retrospectively evaluated. Surgeries were grouped according to intraoperative miotic agent: 0.01% carbachol or 1.0% acetylcholine. Patients receiving no miotic drug served as a control group. Yttrium-aluminum-garnet (YAG) laser posterior capsulotomy was performed on patients with clinically significant PCO. RESULTS: The percentage of eyes requiring YAG laser capsulotomy was similar for the three groups: 21.6% (25 of 91) for the carbachol group, 18.4% (14 of 62) for the acetylcholine group, and 18.6% (53 of 232) for the control group. A chi-squared analysis indicated that the difference among the groups was not statistically significant. The three groups also had similar average follow-up times between surgery and YAG capsulotomy (carbachol group = 52.2 weeks, acetylcholine group = 47.5 weeks, and control group = 48.3 weeks). CONCLUSION: Intraocular miotics do not increase the incidence of PCO.

Acetylcholine↗
PubMed1996

Scanning electron microscopic characteristics of small-incision intraocular lenses.

PURPOSE: To evaluate the surface characteristics of commonly used, small-incision, intraocular lenses (IOLs). METHODS: Representative samples of five groups of foldable IOLs (4 silicone and 1 acrylic) underwent surface and edge-finish examination using a slit lamp. The IOLs were folded using a folding block and forceps. All the IOLs then were examined using a scanning electron microscope. A one-piece polymethylmethacrylate IOL was used for comparing surface-finish characteristics. The IOLs were examined for optic surface quality, edge finish, haptic, haptic/optic junction, and possible post-folding modifications. RESULTS: Slit-lamp evaluation of the surface quality of all of the silicone lenses demonstrated a smooth finish of the optic surface, edge, and haptics. Scanning electron microscopic analysis of the IOLs demonstrated adequately finished haptics or footplates and optics. Excess molding flash was seen on the edges of the some of the silicone IOLs, and no molding flash was observed on others. The acrylic IOL had a somewhat sharper optic edge. Irregular finish of the haptic/optic junctions of some of the IOLs (both silicone and acrylic) was noted. CONCLUSIONS: Currently available foldable IOLs have demonstrated adequate lens finish. However, irregularities of the haptic/optic junctions and molding flash are present on most IOLs evaluated, indicating room for improvement in the finish of foldable IOLs. Phacoemulsification with capsular bag IOL placement may decrease the clinical significance of these relatively subtle lens finish irregularities.

Acrylamide↗
PubMed1996

Visual significance of glistenings seen in the AcrySof intraocular lens.

PURPOSE: To investigate the visual significance of "glistenings" in acrylic intraocular lenses (IOLS). SETTING: John Moran Eye Center, University of Utah, Salt Lake City. METHODS: Seventeen patients who had phacoemulsification with implantation of the AcrySof acrylic IOL were evaluated by slitlamp examination and visual acuity, contrast sensitivity, and glare testing. Ten patients had a silicone posterior chamber IOL in the opposite eye and had testing with similar visual parameters for comparison. Glistenings noted in the acrylic IOLs were graded at the slitlamp. Laboratory analysis of five acrylic IOLs was also done to reproduce the glistenings noted clinically. RESULTS: All 17 patients with the acrylic IOLs had some lenticular glistenings, ranging from trace to 2+. Statistical analysis of visual acuity, contrast sensitivity, and glare testing revealed a statistically significant difference between the acrylic and the silicone IOLs only in contrast sensitivity. Laboratory analysis of the acrylic IOLs showed similar glistenings from 48 to 72 hours after they were placed in balanced salt solution. CONCLUSIONS: A patients who received AcrySof IOLs that came in the AcryPak had some degree of glistenings. There was also a significant decrease in contrast sensitivity compared with that of fellow eyes with silicone IOLs. The glistenings are likely caused by water vacuoles that form within the lens after hydration within the eyes. Further studies are necessary to assess the exact cause of these glistenings.

Acrylates↗
PubMed1996

Neodymium: YAG capsulotomy rates after phacoemulsification with silicone posterior chamber intraocular lenses.

PURPOSE: To retrospectively evaluate the incidence of neodymium: YAG (Nd:YAG) laser capsulotomies for posterior capsule opacification (PCO) in eyes receiving one of two types of capsular-bag-fixated silicone posterior chamber intraocular lenses (IOLs) over 7 years. SETTING: John Moran Eye Center, University of Utah, Salt Lake City. METHODS: Four hundred eighty-eight eyes that had cataract extraction with a continuous curvilinear capsulorhexis and implantation of one of two kinds of silicone posterior chamber IOLs were evaluated to assess the incidence of PCO. One hundred thirty-nine received a one-piece, plate-type IOL (Staar) and 349, a three-piece, modified C-loop IOL (AMO). RESULTS: With an average follow-up of 84.3 weeks in the Staar IOL group and 93.5 weeks in the AMO IOL group, the incidence of posterior Nd:YAG laser capsulotomy for PCO was 30.2% and 39.1%, respectively. CONCLUSION: The incidence of Nd:YAG laser capsulotomy after phacoemulsification with implantation of a silicone posterior chamber IOL was still relatively high with long-term follow-up. Although the proportion of patients with a one-piece silicone IOL requiring Nd:YAG capsulotomy was less than that in the three-piece silicone IOL group, the difference was not statistically significant.

Aged↗