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Biomedical subjects

D J Apple

Publications and source records attributed to D J Apple.

At least 199 records · Page 11Linked to original sources
PubMed1986

Posterior chamber intraocular lenses in a series of 75 autopsy eyes. Part I: Loop location.

Over a period of 27 months, November 1983 to February 1986, 75 eyes obtained postmortem with posterior chamber intraocular lenses (IOLs) were examined at the Center for Intraocular Lens Research, University of Utah Health Sciences Center. These IOLs were studied by histopathological techniques to determine the location of the loops. The most common combination, found in 47% of the specimens, was one loop in the lens capsular sac (bag) and one loop in the ciliary sulcus. In 32% of the specimens, both loops were in the capsular sac; in 17%, both loops were in the ciliary sulcus. Compared to results observed in other autopsy studies, in which capsular fixation was documented in less than 3% of cases, these findings reflect a trend toward capsular sac (in-the-bag) implantation of open-looped posterior chamber IOLs.

Ciliary Body↗
PubMed1986

Posterior chamber intraocular lenses in a series of 75 autopsy eyes. Part II: Postimplantation loop configuration.

We illustrate, from the pathologist's viewpoint, the configuration of posterior chamber lens loops within the eye. The final configuration of these loops is often a "C" shape, particularly following capsular fixation. When one or both loops are placed in the ciliary sulcus, where tissue resistance to loop compressive forces is less than in the capsular sac, an invagination or erosion of the loop into the ciliary body stroma or ciliary muscle frequently occurs. Although a surgeon should first and foremost choose a lens design with which he or she is comfortable in terms of ease of implantation and good clinical results, our pathological observations indicate that a subtle compromise in loop configuration might provide a more physiologically correct configuration in the eye, particularly for those who prefer in-the-bag implantation. Most surgeons prefer a lens design that will provide adequate fixation in the ciliary sulcus if an attempted capsular sac implantation is not successful.

Ciliary Body↗
PubMed1986

Posterior chamber intraocular lenses in a series of 75 autopsy eyes. Part III: Correlation of positioning holes and optic edges with the pupillary aperture and visual axis.

The possibility that undesirable visual complications such as glare, halo, monocular diplopia, or other visual aberrations can result from the presence of posterior chamber lens optic edges or such lens elements as positioning holes or loop-optic junctions within the pupillary aperture has received little attention. There is recent clinical evidence that these phenomena may be clinically significant. In a series of 75 autopsy eyes with posterior chamber intraocular lenses, we have observed that in 71% of cases an optic edge, or element of the optic such as a positioning hole, was situated either within the pupillary aperture and visual axis (average pupillary diameter 3.45 mm) or within 0.5 mm of the pupillary margin. This finding was most common (92%) in cases with asymmetric placement, less common (50%) in cases with symmetric placement. Many more young patients are now undergoing implantation surgery. These patients generally have wider, more mobile pupils, and they may be more aware of subjective symptoms, particularly at night. Subtle changes in implantation techniques and in lens design and manufacture can minimize complications related to this condition. These changes include symmetric loop placement (both loops in the capsular sac or both in the ciliary sulcus) to decrease optic decentration. Other measures such as making partial-depth positioning holes, increasing the size of the optic, eliminating or reducing the number of positioning holes, and placing positioning holes in tabs on the optic edges may function to increase the effective optical zone.

Ciliary Body↗
PubMed1986

Integrity of polydioxanone sutures: a case report.

Certain conditions have been found to hasten the breakdown of absorbable PDS (polydioxanone) sutures. It is important that surgeons handle the sutures carefully to avoid premature breakdown.

Equipment Failure↗
PubMed1985

Histopathologic correlative study of Kelman-style flexible anterior chamber intraocular lenses.

Three of 16 eyes in which Kelman flexible anterior chamber lenses were implanted were obtained for postmortem examination, and the lenses and globes were analyzed histopathologically. Thirteen additional lenses, removed surgically secondary to various complications, were studied by scanning electron microscopy. All of the lenses ere well finished and none showed evidence of degradation or cracking of the polymethylmethacrylate optics or foot plates. Some of the lenses showed deposition of inflammatory debris or erythrocytes, reflecting a clinical history of uveitis. In some cases, the problems seemed to be related to variations in surgical technique or improper sizing.

Aged↗
PubMed1985

Choroiditis in infantile periarteritis nodosa.

The ocular pathologic findings were determined in a case of fatal infantile periarteritis nodosa (IPN). To our knowledge, this case is the first histologically documented report of choroidal inflammation associated with this disease. Since the clinical and pathologic findings of IPN and Kawasaki's disease (KD) are identical, these findings should be sought in cases of KD.

Choroid↗
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

Fungal contamination of balanced salt solution.

A fungal organism, identified as Ulocladium, was isolated from an unopened 15 ml bottle of balanced salt solution. The authors note the importance of visually inspecting solutions used in ophthalmic surgery.

Drug Contamination↗
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

Phthisis bulbi after intraocular lens implantation in a child.

A 4-year-old boy with trisomy 21 and a congenital cataract underwent cataract extraction and implantation of an iris-supported intraocular lens (IOL). Four years later the implant dislocated anteriorly and had to be removed. Now, 11 years postoperatively, the eye is blind, painful and shrunken. IOL implantation in infants and children is theoretically justified to preserve vision, reduce amblyopia and preserve fusion. The use of modern posterior chamber IOLs, especially when implanted in the lens capsular bag (if technically feasible), could reduce the risk of complications. However, until further data are accumulated, a conservative approach is warranted.

Blindness↗
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

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

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↗