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Biomedical subjects

R J Olson

Publications and source records attributed to R J Olson.

At least 109 records · Page 6Linked to original sources
PubMed1985

An analysis of semiflexible, closed-loop anterior chamber intraocular lenses.

We present the pathologic and scanning electron microscopic findings from 44 semiflexible, all polymethylmethacrylate, anterior chamber intraocular lenses (IOLs). These IOLs, which have round, small diameter, closed loops were removed following a variety of complications, including uveitis and/or the uveitis-glaucoma-hyphema syndrome, secondary glaucoma, pseudophakic bullous keratopathy, cystoid macular edema, erosion into uveal tissue (with and without oval pupil), and iris neovascularization. Over 200,000 of these lens styles have been implanted. Even though the number of these IOLs accessioned in our laboratory is small, we feel this analysis documents some of the problems that may be encountered with this IOL design. Many of the complications documented in our series resulted in severe visual loss. In addition to tissue damage that appeared secondary to the mechanical tissue-to-implant interface, other causes of complications included variations in surgical technique, implantation into eyes with preexisting disease (including eyes that had undergone previous surgery), and damage to tissue that occurred during IOL removal.

Anterior Chamber↗
PubMed1985

A comparison of ciliary sulcus and capsular bag fixation of posterior chamber intraocular lenses.

We compare indications, advantages, and disadvantages of ciliary sulcus and lens capsular bag (lens capsular sac) fixation of posterior chamber intraocular lenses (IOLs). Our findings suggest that, whenever possible, it is efficacious to implant the loops of posterior chamber IOLs within the capsular bag. This positions the lens optic and the supporting loops in the natural anatomical position, sequestered from highly vascular uveal tissue and the blood aqueous barrier. This should minimize the potential for complications that may be associated with iris-ciliary body contact. Considering the rapid increase in the number of implantations of IOLs now being performed (approximately 700,000 per year in the United States alone), a possible reduction of even 1% in clinically significant complications would make this effort worthwhile. Widespread application of in-the-bag implantation is predicated on the assumption that the surgeon is proficient with this procedure and that careful follow-up of patients does not reveal any significantly increased incidence of lens dislocation due to zonular rupture.

Adult↗
PubMed1985

Results of a double running suture in penetrating keratoplasty performed on keratoconus patients.

Parallel running 10-0 and 11-0 nylon sutures were used in 76 consecutive penetrating keratoplasties on patients with keratoconus. Removal of the 10-0 suture at eight to 12 weeks allowed for early visual rehabilitation postoperatively. The use of various trephine sizes and the use of a bridle suture versus a scleral ring were evaluated by several visual parameters. The incidence of complications with the double running suture was not greater than that obtained with other suture techniques.

Astigmatism↗
PubMed1984

Opacification, vascularization, and chronic inflammation produced by hydrogel corneal lamellar implants.

Fourteen hydrogel lamellar implants were placed in rabbit corneal stroma. Within six months of implantation, all the rabbit eyes showed some opacification of the cornea, and several of the rabbits had vascularization along the lamellar interface with signs of chronic inflammation. Opacification and vascularization eventually appeared in all 14 eyes, regardless of the water content or oxygen permeability of the lens material. One rabbit was killed, and a histopathologic examination showed evidence of chronic inflammation and scarring. Because the rabbit's sensitivity to an inflammatory nidus makes it a good laboratory test animal, these rabbits' inability to tolerate some of the currently available hydrogel corneal lamellar implants may indicate that such material is unsuitable as a permanent implant for cosmetic refractive surgery in humans.

Animals↗
PubMed1984

Congenital corneal opacification secondary to Bowman's layer dysgenesis.

Progressive, bilateral corneal clouding was noted at birth in an otherwise healthy infant. There was no evidence of an infectious or hereditary cause. A trial of corticosteroids was unsuccessful, and the opacification in both corneas increased during the course of a few months, necessitating penetrating keratoplasty. However, reopacification of both grafts ensued within two to four months, and a second graft was done on the right eye. Histologic examination of both the original corneal buttons and the failed graft from the right eye showed a thickening of Bowman's layer that was three to four times greater than that of normal controls. This was associated with an increased number of keratocytes producing pools of collagen bundles within Bowman's layer. This report documents a unique form of corneal opacification unassociated with other ocular or systemic diseases. This process may be interpreted as a phenomenon in which the cells that contribute to the intrauterine formation of Bowman's layer continue to proliferate in an abnormal and exuberant fashion beyond fetal life, leading to corneal opacification.

Cornea↗
PubMed1984

Phacoanaphylactic endophthalmitis associated with extracapsular cataract extraction and posterior chamber intraocular lens.

We describe the clinicopathologic findings in a patient who underwent extracapsular cataract extraction (ECCE) with insertion of a posterior chamber intraocular lens (IOL). The patient had a sterile hypopyon and anterior uveitis that temporarily subsided but recurred. The inflammation actually worsened after removal of the IOL, and the eye was enucleated. Histopathologic examination showed a pattern consistent with phacoanaphylactic endophthalmitis. We therefore postulate that the patient's complications were due to hypersensitivity to her own lens protein, which remained after the ECCE, rather than to the IOL itself.

Aged↗
PubMed1984

Shearing posterior chamber intraocular lenses: five-year postoperative results.

Long-term follow-up data for 424 patients with an IOLAB Shearing J-loop posterior chamber intraocular lens are presented. One hundred sixty-eight patients were given a complete ophthalmologic exam at five years (59 to 69 months) after surgery. Charts of the remaining 256 patients were reviewed for the most recent visit data. Ten surgeons contributed patients to this follow-up study. Results indicate that 91.5% of the patients in the five-year exam group obtained a visual acuity of 20/40 or better at one year after surgery and 89.3% obtained this visual acuity at five years after surgery, thus showing only a decrease of two percentage points over time. If patients with preoperative pathology or macular degeneration are excluded, the percentage of patients seeing 20/40 or better at five years is 94.0%. Few of the complications observed at five years are implant-related; macular degeneration is the primary condition causing vision worse than 20/40. No macular edema and few corneal problems were observed at five years. Endothelial cell counts were obtained for 53 of the 168 patients examined at five years and averaged 1,947 cells/mm2. The rate of lens dislocation is low, and no clinical evidence of degradation or failure of the polypropylene haptics was noted.

Adult↗
PubMed1984

Biocompatibility of implant materials: a review and scanning electron microscopic study.

The evolution of various plastic materials used in the manufacture of intraocular lenses is reviewed, with special reference to the problem of biocompatibility of lens haptic materials. To date, polypropylene has been found and continues to be a highly effective, relatively inert material, providing good surgical results. However, the present study and other morphologic and chemical studies have provided evidence that indicates long-term alteration of polypropylene may occur. For this reason we believe that further studies of this particular polymer are warranted. Also, a continuing search and trial of other plastics to discover an equivalent or even more efficacious haptic material seems desirable. There is a need for careful long-term follow-up of patients after intraocular lens implantation, particularly of young patients.

Biocompatible Materials↗
PubMed1984

Pathological and scanning electron microscopic evaluation of the 91Z intraocular lens.

We analyzed 18 explanted 91Z anterior chamber lenses by light and scanning electron microscopy. Intermittent touch of the lens loops to the posterior corneal surface and the anterior chamber angle may have occurred. Erosion of the polypropylene loops into the anterior chamber angle recess and into the iris tissue was also observed. Fibrous tissue, uveal tissue, and inflammatory debris were noted on the loops, forming dense synechias at the points of contact with the angle recess. In some lenses the edges of the optics were sharp. Other significant manufacturing defects were rarely seen, and there was no evidence of degradation of polypropylene loops. The problems regarding surgical removal of this lens are discussed.

Anterior Chamber↗
PubMed1984

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Acetates↗
PubMed1984

The treatment of myopia with atropine and bifocals. A long-term prospective study.

Two hundred fifty-three patients were followed for up to nine years (mean, 4 1/4 years). They were on a regimen of atropine 1% once a day in an attempt to retard myopic progression. Their rate of myopic progression prior to atropine treatment was compared with 146 controls. The rates of myopic progression during and after treatment were also compared to those of the controls. The results from several analyses showed a marked flattening in the rate of myopic progression during treatment, and the rate of myopic progression after treatment ran parallel to those in the control group. Age in relation to myopic progression was evaluated in subgroups. A variation existed in the rate of myopic progression in the controls. The fastest rate of myopic progression occurred between eight and 12 years of age, and the slowest rate of myopic progression developed in those patients over 18 years of age.

Adolescent↗
PubMed1984

Anterior segment complications and neovascular glaucoma following implantation of a posterior chamber intraocular lens.

Lens implantation is now a highly successful operation. Although follow-up over 5 to 10 years with posterior chamber lenses is incomplete, the complication rate appears to be as low or lower than other lens styles. We present an exception: a clinicopathologic analysis of a globe, enucleated 4 years postoperatively, which in spite of uneventful implantation of a posterior chamber lens, developed neovascular glaucoma. Microscopic studies suggest several mechanisms for this rare complication including deep erosion of a prolene loop into the ciliary body, anterior segment ischemia, and breakdown of the blood-aqueous barrier. Scanning microscopy showed cracking of this deeply embedded loop, a finding we interpret as possible stress cracking and/or oxidation. The more flexible loops now used in modern lenses may decrease the chance of deep erosion. Implantation of a loop in the capsular bag may minimize the danger of both erosion and loop degradation. Patients should be followed long-term in order to recognize and treat these rare, but potentially disastrous complications.

Anterior Chamber↗
PubMed1984

Analysis of the Hessburg-Barron vacuum trephine.

We tested the Hessburg-Barron vacuum trephine on 23 human cadaver eyes for accuracy and quality of cut. The trephine was found to make accurate, spherical cuts in the anterior corneal stroma. With penetration, the cut became beveled, leaving the posterior corneal button diameter larger than the anterior diameter especially if the trephine was lifted. The results are discussed relative to conventional techniques.

Cadaver↗
PubMed1984

Variation in disposable corneal trephine sharpness.

During a recent corneal transplantation procedure, it was discovered that the disposable corneal trephine being used was dull; it would not even penetrate Bowman's layer of the recipient cornea. In contrast, the replacement trephine was sharp. The appreciable variation of trephine sharpness was confirmed by scanning electron microscopy. The consequences of poor quality in an ophthalmic surgical instrument are discussed.

Corneal Transplantation↗
PubMed1984

Tetracaine toxicity.

Severe ocular complications developed in a patient after use of a topical anesthetic (tetracaine 0.5% ophthalmic ointment) over a period of two months.

Female↗
PubMed1984

Herpes zoster.

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Adrenal Cortex Hormones↗
PubMed1984

Sedimentation field-flow fractionation: a method for studying particulates in cataractous lens.

It is shown that the technique of sedimentation field-flow fractionation (sedimentation [sed] FFF) can be used to determine the particle content and particle size distribution of normal and cataractous lenses. A 31-year-old normal human lens, for example, showed a particle content of 1.5% by weight with diameters ranging from 0.12 micron to 0.9 micron. The urea insoluble material present in the nuclear and cortical fractions from a densely cataractous lens contained particles ranging from 0.12 micron to 1.7 micron, with average sizes of 0.83 micron and 0.82 micron respectively, for the two fractions. These numbers offer a basis for comparison; their actual values may be shifted slightly either up or down depending on the assessment of particle density. These sizes, which correspond to molecular weights of around 2 X 10(9) dalton, are larger than previously reported for lens particulates. The sed FFF method is thus seen to permit fractionation and size analysis of small amounts of lens material in times less than one hour.

Cataract↗