Biomedical subjects

A S Crandall

Publications and source records attributed to A S Crandall.

At least 19 recordsLinked to original sources

PubMed2001

Spontaneous late dislocation of intraocular lens within the capsular bag in pseudoexfoliation patients.

PURPOSE: To identify a delayed complication of cataract surgery in patients with zonular weakness caused by pseudoexfoliation syndrome. DESIGN: Retrospective observational case series. PARTICIPANTS: Eight eyes in seven patients with clinically diagnosed pseudoexfoliation syndrome who had undergone previous uncomplicated cataract extraction and placement of a posterior chamber intraocular lens. METHODS: This study evaluated eight cases of late spontaneous dislocation of posterior chamber intraocular lenses within the capsular bag in patients with pseudoexfoliation syndrome. Data were gathered retrospectively from patients' operative reports, medical records, and pathology reports. MAIN OUTCOME MEASURES: (1) Interval between original surgery and dislocation; (2) final best-corrected visual acuity and ocular outcome. RESULTS: All patients had a diagnosis of pseudoexfoliation syndrome and had previously undergone uncomplicated cataract surgery. No patient had any other predisposing factors that would lead to zonular dehiscence or weakness. Delayed dislocation of the entire capsular bag containing the intraocular lens (IOL) occurred spontaneously in all cases. Mean time from IOL implantation to dislocation was approximately 85 months (7 years and 1 month; range, 57-115 months) after surgery. Seven eyes were treated successfully with IOL exchange: six with placement of an anterior chamber IOL and one with scleral fixation of a posterior chamber IOL. The remaining case was treated by scleral fixation of the dislocated IOL. Gross pathology analysis of seven cases confirmed the presence of the IOL within the intact capsular bag. Six eyes have achieved final best-corrected visual acuity of 20/40 or better. CONCLUSION: Patients with pseudoexfoliation syndrome may be at risk for delayed spontaneous dislocation of IOL within the capsular bag after uncomplicated cataract surgery. Awareness of this newly recognized long-term complication may justify a reevaluation of surgical considerations for cataract removal in these patients.

Aged↗

PubMed2001

Ab externo scleral fixation of the Cionni modified capsular tension ring.

The Cionni modified capsular tension ring (CTR) allows for scleral fixation in cases of significant zonular dialysis, providing long-term centration of in-the-bag foldable intraocular lenses. Previous techniques of suture placement require placement of the primary incision along the axis of zonular weakness or enlarging and/or distorting the primary incision to attain proper positioning. They also use blind passes of the needle under the iris to approximate the ciliary sulcus. We describe an external closed-system approach for preplacing 10-0 polypropylene sutures in the ciliary sulcus for a Cionni modified CTR under topical anesthesia. This technique does not use blind passes of the suture needle and results in accurate placement of the sutures in the ciliary sulcus under a closed and stable system.

Adolescent↗

PubMed2001

Glaucoma surgery treatment patterns of ASCRS members--2000 survey.

A survey of glaucoma surgery parameters was mailed to all the United States members of the American Society of Cataract and Refractive Surgery in 1999 and 2000. Of the 5659 surveys mailed, 725 (13%) were returned. The survey assessed parameters used in glaucoma surgical treatment. Preferred surgery treatment patterns were cross-tabulated with fellowship training in glaucoma (9.3%) and geographic location. This report summarizes current practice styles and patterns of comprehensive ophthalmologists in the United States as derived from the survey.

Cross-Sectional Studies↗

PubMed2001

Anesthesia modalities for cataract surgery.

Modern cataract surgery represents an amalgam of new technologists which may include phacoemulsification, foldable intraocular lenses and, in many instances, clear corneal incision. The fusion of newer techniques has allowed for a re-evaluation of the anesthetic needs for cataract surgery. These minimally incisive surgical procedures have allowed us to reintroduce a very old technique: topical anesthesia into cataract surgery. This article reviews the present day techniques that are available from the use of general anesthesia to the use of injection technique as well as topical.

Anesthesia↗

PubMed2000

Visual complaints associated with the AcrySof acrylic intraocular lens(1).

PURPOSE: To describe the visual complaints of a series of patients implanted with the AcrySof(R) (Alcon Surgical) acrylic intraocular lens (IOL) that resolved with IOL exchange. SETTING: Jules Stein Eye Institute, Los Angeles, California, and John A. Moran Eye Center, Salt Lake City, Utah, USA. METHODS: This was a retrospective review of patients who had AcrySof IOL exchange from January 1997 to December 1998. RESULTS: Eight patients (9 eyes) with bothersome visual symptoms following AcrySof IOL implantation were identified. Problems included glare, halos around point light sources, and peripheral arcs of light, often worse at night. In each case, the IOL was well-centered in the capsular bag and there was no significant posterior capsule opacification. Six patients (7 eyes) had the MA30BA model with a 5.5 mm optic, and 2 patients (2 eyes) had the MA60BM model with a 6.0 mm optic. No extralenticular reasons for the patients' complaints could be identified. Exchanging the AcrySof IOLs with silicone or poly(methyl methacrylate) IOLs alleviated most symptoms. In 5 of 8 patients, dysphotopsias resolved completely. CONCLUSIONS: A small number of patients implanted with AcrySof IOLs have specific complaints of glare, halos, and peripheral arcs of light. Optical considerations that may help explain these symptoms include the high refractive index of the IOL material and the truncated design of the optic. Patients who are highly observant and those with large pupils may be particularly symptomatic. Intraocular lens exchange may be necessary in some cases.

Acrylates↗

PubMed1999

A comparison of patient comfort during cataract surgery with topical anesthesia versus topical anesthesia and intracameral lidocaine.

OBJECTIVE: To determine whether intraocular lidocaine increases patient comfort during cataract surgery while under topical anesthesia. DESIGN: Prospective, randomized, double-masked, placebo-controlled clinical trial. PARTICIPANTS: Both men and women between 45 and 85 years of age who were scheduled for elective cataract surgery while under topical anesthesia participated. Sixty-eight patients were randomized to each group. INTERVENTION: Patients were randomized to receive either topical anesthesia plus intracameral 1% preservative-free lidocaine or intracameral balanced salt solution. MAIN OUTCOME MEASURES: Patient assessment of pain during delivery of the anesthesia, surgery, and after surgery using a visual analog pain scale was measured. Patients also recorded the degree to which they were bothered by tissue manipulation and the microscope light. Surgeon assessments of operative conditions, patient cooperation, and intraoperative complications were recorded. The attending anesthesiologist recorded any required supplemental intravenous sedation and any increase in pulse or increase in blood pressure. RESULTS: There was no significant difference in patient-reported pain scores for delivery of anesthesia (P = 0.902), surgery (P = 0.170), or after surgery (P = 0.680). Patients in the lidocaine group reported being less bothered by tissue manipulation (P = 0.021). The surgeon assessment showed more patient cooperation in the lidocaine group (P = 0.043). CONCLUSIONS: Both topical anesthesia alone and topical anesthesia plus intracameral lidocaine provide good operative conditions for the surgeon and comfortable surgical circumstances for the patient. Injection of intraocular lidocaine increases patient cooperation and decreases the degree to which patients are bothered by tissue manipulation, two outcomes that justify its use.

Administration, Topical↗

PubMed1999

Cataract surgery complications in 1 year at an academic institution.

PURPOSE: To delineate all complication rates of cataract surgery and define normative rates, trends, and outliers as part of continuous quality management. SETTING: John A. Moran Eye Center, University of Utah Health Sciences Center, Salt Lake City, Utah, USA. METHODS: All cataract surgeries done at the John A. Moran Eye Center from July 1, 1996, to June 30, 1997 (1 complete academic year) were reviewed for intraoperative complications using operative reports. Cases with documented preoperative zonular dehiscence, traumatic capsule breakage, previous vitreous in the anterior chamber, or an accompanying major secondary procedure (e.g., trabeculectomy, corneal transplantation) were eliminated from the study. Over this year, 1729 cataract surgeries were performed by 12 attending physicians, 3 fellows, and 4 residents. Cases of cataract removal with intraocular lens implantation ranged from 18 to 510 per surgeon. RESULTS: There were 44 cases (2.54%) of posterior capsule rupture, with 29 (1.68%) requiring vitrectomy. Most capsule breakages occurred during phacoemulsification. The Student t test showed no statistically significant difference in the incidence of capsule breakage among surgeons (incidence from 0% to 6.25%). All cases were started as phacoemulsification, with 6 conversions (0.35%) to planned extracapsular cataract extraction. CONCLUSIONS: In evaluating continuous quality management, no outliers were found within our center. Phacoemulsification was the part of cataract surgery most likely to cause posterior capsule rupture.

Academic Medical Centers↗

PubMed1999

Nonpenetrating filtering procedures: viscocanalostomy and collagen wick.

Unroofing of Schlemm's canal without entering the anterior chamber has been performed previously to lower intraocular pressure. Initial results were good, but long-term results were discouraging, and the techniques were abandoned. Recently, two variations have surfaced. Visco canalostomy is a technique devised by Robert Stegmann of South Africa. The glaucoma drainage device (Collagen Wick) was initially introduced by Koslov in Russia. These techniques are described in this article.

Biocompatible Materials↗

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

Prospective evaluation of topical versus retrobulbar anesthesia: a converting surgeon's experience.

PURPOSE: To evaluate and compare the efficacy of topical versus retrobulbar anesthesia for cataract surgery performed by a surgeon newly converting to the topical technique. SETTING: Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Ninety patients were prospectively assigned by permuted block restricted randomization to receive topical (Group 1; n = 45) or retrobulbar (Group 2; n = 45) anesthesia. Group 1 received topical bupivacaine 0.75% and intravenous midazolam and fentanyl for anesthesia. Group 2 received intravenous methohexital followed by retrobulbar block with an equal mixture of lidocaine 2% and bupivacaine 0.75% plus hyaluronidase 150 units. A visual pain analog scale was used to assess the degree of pain during anesthesia administration and surgery and postoperatively. The degree to which eye movement, touch, and light caused patient discomfort was assessed. Intraoperative conditions and complications were recorded. RESULTS: Intraoperative operating conditions were significantly better in Group 2 (P < .05). There was a small but statistically significant difference in the degree of discomfort during anesthesia administration and surgery (P < .05). There was no difference in postoperative discomfort. Chemosis, subconjunctival hemorrhage, and eyelid hemorrhage occurred only in Group 2, in which there was one retrobulbar hemorrhage. Although eyelid squeezing and ocular motility were present more frequently in Group 1, neither was a problem to the surgeon. CONCLUSION: Cataract surgery was safely performed by a surgeon converting to topical anesthesia. After a distinct learning curve, the procedure was performed with minimal patient discomfort. Surgical training and patient preparation are the key to safe use of topical anesthesia.

Administration, Topical↗

PubMed1998

Decentration of 3-piece versus plate-haptic silicone intraocular lenses.

PURPOSE: To compare the incidence of decentration with 2 types of silicone intraocular lenses (IOLs). SETTING: John A. Moran Eye Center, University of Utah Medical Center, Salt Lake City, Utah, USA. METHODS: Selection criteria for this retrospective study included patients who had uncomplicated cataract surgery with a clear cornea or scleral tunnel incision with a curvilinear capsulorhexis and capsular bag implantation of a silicone IOL. After a mean follow-up of 14 months (range 12 to 18 months), 54 eyes implanted with a 3-piece lens (AMO SI-30) and 58 eyes implanted with a plate-haptic lens (Staar AA403) were examined for posterior chamber IOL decentration. The decentration criterion was 0.5 mm or more from the center of the pupil. Detailed chart review of preoperative and postoperative measurements was performed for each patient. RESULTS: Eighteen of the 3-piece IOLs (33%) and 11 of the plate-haptic IOLs (20%) were decentered 0.5 mm or more (P = .129). Using photographic analysis, the mean IOL decentration with the 3-piece IOL (1.12 mm +/- 0.198 [SD]) was significantly greater than with the plate-haptic IOL (0.632 +/- 0.278 mm)(P < .001). No statistically significant correlation was found between the centered or decentered IOL groups' preoperative refraction, axial length, capsulorhexis size, type of incision, or rate of neodymium:YAG laser capsulotomy. CONCLUSIONS: No statistically significant difference was seen between the decentration rates of 3-piece and plate-hepatic IOLs; however, the amount of decentration with the 3-piece IOL was significantly greater than with the plate-hepatic IOL. Other factors did not contribute to IOL decentration.

Follow-Up Studies↗

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

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

Anterior lens capsule rupture caused by air bag trauma.

PURPOSE: To report a child with anterior lens capsule rupture caused by air bag inflation. METHODS: A 10-year-old girl sustained a rupture of the right anterior lens capsule secondary to air bag deployment during a minor automobile accident. The evaluation included orbital ultrasound and orbital computed tomography. RESULT: The right eye underwent lens aspiration with intraocular lens placement. Postoperatively, the patient did well with 20/25 best-corrected visual acuity. CONCLUSION: Our case, in which the patient's lens capsule was ruptured by air bag inflation, illustrates that air bag deployment, even in minor low-speed accidents, can cause severe blunt trauma to the eye.

Accidents, Traffic↗

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

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

Combined phacoemulsification, intraocular lens implantation, and trabeculectomy.

PURPOSE: To analyze the results of phacoemulsification and posterior chamber intraocular lens (IOL) implantation combined with trabeculectomy. SETTING: John Moran Eye Center, University of Utah, Salt Lake City. METHODS: Two hundred twelve eyes of 174 patients with glaucoma and cataracts were analyzed retrospectively after cataract removal by phacoemulsification with posterior chamber IOL implantation combined with trabeculectomy. RESULTS: With an average follow-up of 26 months, patients had a significant improvement in visual acuity. The preoperative mean intraocular pressure (IOP) of 23.1 mm Hg decreased postoperatively to 15.9 mm Hg. Mean number of glaucoma medications decreased from 1.85 preoperatively to 0.41 postoperatively. Twenty-one patients (10% had a postoperative IOP of greater than 21 mm Hg, and seven required trabeculectomy revisions. CONCLUSION: Combined phacoemulsification, posterior chamber IOL implantation, and trabeculectomy yielded excellent results in the treatment of patients with both cataract and glaucoma.

Adult↗