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Biomedical subjects

Mark Packer

Publications and source records attributed to Mark Packer.

14 recordsLinked to original sources
PubMed2003

Management of posterior polar cataract.

In this technique for managing posterior polar cataract, extreme care is taken not to overpressurize the anterior chamber or capsular bag to prevent posterior capsule rupture. Minimal hydrodissection and hydrodelineation are performed. The nucleus is extracted using minimal ultrasound energy. Viscodissection is used as a primary technique to mobilize the epinucleus and cortex. A protective layer is preserved over the posterior polar region until the conclusion of the extraction procedure to minimize the risk of loss of lens material into the vitreous cavity in the case of a capsule defect.

Capsulorhexis↗
PubMed2003

Incidence and outcomes of lasik with diffuse lamellar keratitis treated with topical and oral corticosteroids.

PURPOSE: To analyze the incidence and clinical outcomes of patients developing diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) treated with topical and oral corticosteroids. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: A retrospective analysis of the last consecutive 1000 LASIK cases was performed. Eyes developing stage 3 DLK or at risk for progressing to stage 3 were treated with a combination of high-dose prednisolone acetate 1% and oral prednisone and evaluated for corneal scarring, loss of best spectacle-corrected visual acuity (BSCVA), and deviation from the intended refractive outcome. RESULTS: Diffuse lamellar keratitis developed in 40 eyes (4%). It progressed to stage 3 in 7 eyes (17%). Oral and topical steroids were used in 22 eyes (55%). The mean variation from the desired refractive outcome was 0.14 diopter +/- 0.53 (SD). There were no instances of corneal scarring or permanent loss of BSCVA. No eye had interface irrigation. CONCLUSIONS: Treatment of severe DLK with high-dose topical and oral corticosteroids produced excellent results without flap lifting and interface irrigation.

Administration, Oral↗
PubMed2003

Refractive lens exchange with a multifocal intraocular lens.

Refractive lens exchange with a multifocal intraocular lens is becoming a more popular method of refractive surgery in the presbyopic patient. The limitations of keratorefractive surgery have led to a resurgence of lens exchange surgery for patients with prescriptions outside the limits of corneal refractive procedures, in addition to patients with routine refractive errors requesting a surgical procedure to achieve emmetropia and also address presbyopia. Side effects of multifocal technology including unwanted photic phenomena and deterioration in contrast sensitivity are being further defined and evaluated to better assess the effects of these intraocular lenses on functional vision and patient satisfaction. Attention to detail in regards to proper patient selection, preoperative measurements, intraoperative technique, and postoperative management will ultimately result in excellent outcomes and improved patient acceptance of this effective technique.

Device Removal↗
PubMed2002

Suture fixation of a foldable acrylic intraocular lens for ectopia lentis.

A 5-year-old boy with severe ectopia lentis had bilateral lensectomy and suture fixation of a foldable acrylic intraocular lens (IOL) through a 3.0 mm clear corneal incision. Sodium hyaluronate (Healon GV) enhanced stability of the crystalline lens during aspiration and maintenance of the anterior chamber during passage of the needles through the ciliary sulcus. The haptic design of the single-piece AcrySof (Alcon) IOL permitted secure fixation of the suture to the haptic. The patient experienced rapid visual rehabilitation, achieving an uncorrected visual acuity of 20/40 in both eyes.

Acrylic Resins↗
PubMed2002

Stabilization of flat anterior chamber after trabeculectomy with Healon5.

A 64-year-old phakic patient had a trabeculectomy complicated by complete shallowing of the anterior chamber 10 days postoperatively. Despite repair of a conjunctival wound dehiscence and reformation of the anterior chamber with sodium hyaluronate 3.0%-chondroitin sulfate 4.0% (Viscoat), he had a flat anterior chamber again the following day with 360 degrees of pupillary synechias and lens-to-cornea touch. Sodium hyaluronate 2.3% (Healon5) instilled through a paracentesis at the slitlamp lysed the synechias, stabilized the anterior chamber, facilitated filtration, and prevented complications from hypotony. The unique properties of Healon5 allowed for a conservative and less invasive approach in the management of this particular complication.

Anterior Chamber↗
PubMed2002

Refractive lens exchange with the array multifocal intraocular lens.

PURPOSE: To study the safety and efficacy of refractive lens exchange as a refractive surgery modality in the presbyopic population. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This retrospective review of patient charts included patient selection, preoperative evaluation, management of astigmatism, surgical technique, postoperative visual outcome, and complications. The study included 68 eyes comprising 32 bilateral and 4 unilateral refractive lens exchanges. RESULTS: All patients having bilateral refractive lens exchange achieved an uncorrected binocular visual acuity of 20/40 and J5 or better 1 to 3 months postoperatively. More than 90% achieved an uncorrected binocular visual acuity of 20/30 and J4 and nearly 60%, of 20/25 and J3. CONCLUSION: Refractive lens exchange was a safe and effective refractive surgery modality in presbyopic patients.

Aged↗
PubMed2002

Immersion A-scan compared with partial coherence interferometry: outcomes analysis.

PURPOSE: To compare 2 methods of axial length measurement, immersion ultrasonography and partial coherence interferometry, and to elucidate surgical outcomes based on immersion measurements. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: Axial length measurements in 50 cataractous eyes were obtained by optical biometry (IOLMaster, Zeiss Humphrey Systems) and immersion ultrasound (Axis II, Quantel Medical), and the results were compared. Intraocular lens (IOL) power calculations in the same eyes after cataract extraction and posterior chamber IOL implantation were evaluated retrospectively based on the postoperative spherical equivalent prediction error. RESULTS: Immersion ultrasonography and partial coherence interferometry measurements correlated in a highly positive manner (correlation coefficient = 0.996). Outcomes analysis demonstrated 92.0% of eyes were within +/-0.5 diopter of emmetropia based on immersion axial length measurements. CONCLUSION: Immersion ultrasonography provided highly accurate axial length measurements and permitted highly accurate IOL power calculations.

Biometry↗
PubMed2002

Comparison of sonic and ultrasonic phacoemulsification using the Staar Sonic Wave system.

PURPOSE: To compare the performance of sonic phacoemulsification with that of ultrasonic phacoemulsification in regard to 1-day postoperative visual acuity, corneal edema, and procedure efficiency. SETTING: Oregon Eye Institute, Eugene, Oregon, USA. METHODS: This prospective nonrandomized study comprised 86 eyes with mild to moderate nuclear sclerotic cataract. Forty-three eyes had sonic and 43 ultrasonic phacoemulsification using the Staar Sonic Wave phacoemulsification system. The mean age was 76 years in the ultrasonic group and 71 years in the sonic group. The mean nuclear sclerosis was 2.0+ in the sonic group and 1.9+ in the ultrasonic group. Patient age, lens density, postoperative corneal edema, 1-day postoperative uncorrected visual acuity (UCVA), and the percentage of eyes with a visual acuity of 20/40 or better were determined. In addition, the mean ultrasonic and sonic times, mean percentage phaco power, and mean effective phaco time (EPT) were calculated in each group. RESULTS: Both groups had a 5% incidence of trace corneal edema. The mean UCVA was 20/41 in the ultrasonic group and 20/42 in the sonic group. Seventy-nine percent of eyes in the ultrasonic group and 74% in the sonic group had a UCVA of 20/40. The mean percentage phaco power was 7.2% and 7.6% in the ultrasonic group and sonic group, respectively. The mean EPT was low in both groups, 4.0 and 2.9 seconds, respectively. CONCLUSION: Sonic technology yielded outcomes similar to those of ultrasonic phacoemulsification with respect to postoperative visual acuity and corneal edema in patients with average density nuclear sclerotic cataract.

Corneal Edema↗
PubMed2002

New phacoemulsification technologies.

To examine recent developments in the field of phacoemulsification, a literature review was conducted for each system described. the review included peer- reviewed articles, information from manufacturers, and meeting presentations by surgeons. our personal experience with systems we have used forms the underlying basis of our evaluation. data for erbium: YAG laser phacoemulsification came from an interim summary of the U.S. Food and Drug Administration monitored study. Data for NeoSoniX came from a prospective evaluation of phacoemulsification in 25 eyes performed at the Oregon Eye Surgery Center. The development of new technology has allowed safer, more efficient phacoemulsification. Each surgeon should evaluate new developments to achieve the greatest possible benefit for patients.

Animals↗
PubMed2002

The Staar Wave.

Explore the source record for details and available documents.

Equipment Design↗
PubMedDate not supplied

Prospective randomized trial of an anterior surface modified prolate intraocular lens.

PURPOSE: We compare the contrast sensitivity obtained with an anterior surface modified prolate intraocular lens with the contrast sensitivity obtained with a standard spherical intraocular lens. METHODS: Patients presenting for cataract surgery in one eye were randomized to receive either the Tecnis Z9000 intraocular lens (Pharmacia) or the AMO AR40e Opti-Edge intraocular lens (AMO). Sine wave grating contrast sensitivity testing under mesopic and photopic conditions served as the principal outcome measure. RESULTS: The Tecnis Z9000 intraocular lens provided statistically significantly better contrast sensitivity at 1.5 and 3 cycles per degree under mesopic conditions and at 6, 12 and 18 cycles per degree under photopic conditions. CONCLUSION: The use of a modified prolate intraocular lens during cataract surgery has the potential to improve contrast sensitivity under both mesopic and photopic conditions.

Aged↗