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Biomedical subjects

F E O'Donnell

Publications and source records attributed to F E O'Donnell.

At least 19 recordsLinked to original sources
PubMed1998

Laser treatment of solar elastosis with epithelial preservation.

BACKGROUND AND OBJECTIVE: Laser resurfacing has gained wide acceptance for the treatment of actinic facial skin. However, postoperative care of the face is reasonably complicated and prolonged erythema is common. To simplify the postoperative care and to possibly reduce the duration of the erythema, we investigated a laser treatment that spares the epithelium. STUDY DESIGN/MATERIALS AND METHODS: A 980 nm diode laser was used with a spherical optic handpiece to focus the light in the dermis. We treated in vitro breast and facial skin and measured the tissue shrinkage and the histological changes. We also treated two patients and harvested the tissue after 6 and 21 days of wound healing. RESULTS: The diode laser treatment does not ablate the epidermis. The tissue shows shrinkage (16% at 8W) similar to three passes of the scanned carbon dioxide laser treatment (15%). Thermal damage in the dermis is similar to the residual damage left after laser resurfacing with the scanned carbon dioxide laser. After 21 days the tissue shows new collagen and an abundance of young elastin fibers. CONCLUSIONS: These investigations indicate that solar elastosis in skin can be treated with the 980 nm diode laser while preserving the epithelial layer.

Carbon Dioxide↗
PubMed1990

Prospective study of posterior capsule-zonular disruption during extracapsular cataract extraction: eliminating iatrogenic disruption.

We modified our surgical techniques after analyzing the mechanisms responsible for posterior capsule-zonular disruption with or without vitreous loss in 250 consecutive extracapsular cataract extraction cases. We applied the derived principles and prospectively studied the subsequent 1,500 cases. Modifications in our surgical protocol included the use of a Honan balloon for a longer interval (at least 60 minutes preoperatively) and more aggressive surgical expansion of poorly dilating pupils. Furthermore, complete YAG anterior capsulotomy performed after the retrobulbar block appeared to minimize zonular stress associated with mechanical anterior capsulotomy. We reduced the risk of posterior capsule-zonular disruption from 4.8% (2.4% vitreous loss) to zero, eliminating this complication completely in our last 1,000 cases.

Cataract Extraction↗
PubMed1989

Epithelial downgrowth following wound dehiscence after extracapsular cataract extraction and posterior chamber lens implantation: surgical management.

Epithelial downgrowth occurred along a fistulous (nonfiltering) tract containing an incarcerated anterior capsular flap after extracapsular cataract extraction and posterior chamber lens implantation complicated by wound dehiscence. Months later, a YAG posterior capsulotomy was performed before it was realized that posterior capsule opacification was associated with epithelial downgrowth involving the posterior capsule. Surgical management of epithelial downgrowth after extracapsular cataract extraction and posterior chamber lens implantation is discussed, with emphasis on the role of combined cryotherapy, dissection of the retrocorneal membrane, and complete removal of the capsular bag. Histopathologically, we found it difficult to differentiate lens epithelial cells from corneal epithelial downgrowth within the capsular bag, but monoclonal antibody for keratin may help identify corneal epithelial cells.

Anterior Chamber↗
PubMed1989

Ciliochoroidal effusions after neodymium:YAG posterior capsulotomy: association with pre-existing glaucoma and uveitis.

Two patients with a history of glaucoma and a propensity for uveitis developed ciliochoroidal effusions following Nd:YAG laser posterior capsulotomy. Both patients experienced a waxing and waning course with eventual resolution of symptoms after a steroid regimen. The ciliochoroidal effusions were presumed to be secondary to uveitis induced by the YAG laser surgery. The role of glaucoma, previous surgeries, and an open posterior capsule is uncertain but may have predisposed these patients to ciliochoroidal detachment. We advise caution in performing YAG posterior capsulotomy in patients with glaucoma and a known propensity for uveitis.

Aged↗
PubMed1987

Comparative study of the effects of optic design on lens epithelium in vitro.

We performed two tissue culture experiments designed to compare the effects of various posterior chamber optics on lens epithelium. In the first experiment, we recorded, by phase contrast microphotography, the migration of rabbit lens epithelium exoplants placed adjacent to the optic of various posterior chamber lenses. In the second experiment, we used phase contrast microphotographs to document the effects of various posterior chamber optics when gently placed on a confluent layer of rabbit lens epithelium. From our in vitro studies, we conclude the following: There is inhibition of lens epithelial migration and even cytotoxic effects from direct contact with polymethylmethacrylate optics; glass optics have appreciably less effect on lens epithelium; polymethylmethacrylate optics with ridges (complete annulus or incomplete) do not inhibit lens epithelial migration as well as planoconvex lenses, and they do not have a cytotoxic effect except at the points of contact between the ridge and the supporting surface.

Animals↗
PubMed1986

Lens epithelial inhibition by PMMA optic: implications for lens design.

It has been a clinical impression that posterior chamber lens implants in some way inhibit opacification of the posterior lens capsule after extracapsular cataract extraction. The mechanism of this inhibition is unclear; it may be related to mechanical contact or blockage of migration of lens epithelial cells, or possibly to the leeching of toxic factors from the lens itself. A better understanding of the exact mechanism of opacification inhibition may have important clinical implications for intraocular lens design. For example, some lens designs that facilitate Nd:YAG capsulotomy by physically separating the posterior chamber lens and the posterior capsule may result in less inhibition and in fact more opacification of posterior capsules. We performed in vitro tissue culture studies of the effect of the polymethylmethacrylate (PMMA) optic of a planoconvex intraocular lens on cultured rabbit lens epithelium. These studies demonstrated both inhibition of lens epithelial migration beneath the PMMA optic (plano side down) as well as metaplasia and necrosis of lens cells growing directly beneath the optic. The clinical implications of these studies for intraocular lens design are discussed.

Animals↗
PubMed1986

Medial ectropion: association with lower lacrimal obstruction and combined management.

Nine consecutive patients who presented with a medial ectropion (12 eyelids) and epiphora were prospectively evaluated and surgically managed. Medial ectropion was successfully corrected in all 12 eyelids (mean follow-up 12.2 months). A lateral tarsal strip procedure (Anderson procedure) was used to correct the horizontal lid laxity. Resecting the retractors of the lower lid subjacent to the punctal area corrected the punctal eversion. Prior to medial ectropion repair, three of the 12 eyes demonstrated evidence of complete obstruction at or below the level of the lacrimal sac. These patients required concurrent dacryocystorhinostomy (DCR) in addition to repair of the medial ectropion. DCR with silicone intubation obviated the need for anastomosis of lacrimal sac and nasal mucosal flaps, and it corrected the punctal stenosis. Histopathologic examination of the sac specimens confirmed chronic inflammation. One of six patients without complete obstruction required DCR after medial ectropion repair and punctoplasty. Medial ectropion may predispose to lower lacrimal obstruction. In turn, the epiphora may lead to aggravation of the medial ectropion as a result of wiping of tears.

Dacryocystorhinostomy↗
PubMed1985

Posterior capsular-zonular disruption in planned extracapsular surgery.

The incidence of inadvertent posterior capsule-zonular disruption at each stage of planned extracapsular cataract extraction was studied in a consecutive series of 250 cases. Disruption occurred during nucleus expression in 0.8%, during cortical cleanup in 3.2%, during removal of anterior capsular flaps in 0.4%, during polishing of the posterior capsule in 0.4%, and during posterior chamber lens (Sinskey-style) implantation in 0%. No cases of subluxation of the posterior chamber lens were observed (mean follow-up, 22 months). The overall incidence of posterior capsule-zonular disruption was 4.8%. Vitreous loss occurred in one half of these cases (2.4% of eyes). No cases of dislocation of the nucleus into the vitreous occurred. In 50% of the cases of posterior capsule-zonular disruption (2.4% of eyes), prompt recognition and proper management avoided disruption of the vitreous face. In 80% of these cases with posterior capsule-zonular disruption but intact vitreous face, it was possible to remove sufficient cortex and to proceed with uncomplicated posterior chamber lens implantation.

Cataract Extraction↗
PubMed1985

Role of the posterior capsule in the prevention of postoperative bacterial endophthalmitis: experimental primate studies and clinical implications.

The posterior capsule has an important effect on the risk of postoperative bacterial endophthalmitis. In order to investigate whether the posterior capsule inhibited the spread of infection into the vitreous we performed extracapsular cataract extraction in both eyes of 10 primates. In one eye of each primate the posterior capsule was left intact and in the other eye a large posterior capsulectomy was performed. When the anterior chambers were challenged with equivalent inocula of Staphylococcus aureus, one of 10 eyes with an intact posterior capsule developed culture-positive vitreous infection. In contrast, nine of 10 eyes with a large posterior capsulectomy developed culture-positive vitreous infection. In a second experiment we investigated the effect of an intraocular lens on the barrier effect. Ten primates received extracapsular cataract extraction in both eyes and pseudophakic implantation. In one eye of each primate the posterior capsule was left intact and a J-loop monoplanar lens was implanted in the ciliary sulcus. In the other eye of each primate a large posterior capsulectomy was followed by implantation of a monoplanar, non-vaulted pseudophakos into the anterior chamber. None of the 10 eyes with a posterior capsule intact and a posterior chamber lens in place developed positive vitreous cultures or histopathological evidence of vitreous infection. Thus the presence of a posterior chamber lens did not appreciably compromise the barrier effect of the intact posterior capsule. 40% of the eyes with a large posterior capsulectomy and a non-vaulted pseudophakos in the anterior chamber developed culture-positive vitreous infection, and 60% of the eyes showed histopathological evidence of vitreous infection.

Animals↗
PubMed1985

Open angle glaucoma in melanosis oculi: response to laser trabeculoplasty.

The case for an association between secondary open angle glaucoma and melanosis oculi is strengthened by our recent observation of a teenaged male with advanced glaucomatous damage in the eye with melanosis oculi. This report summarizes his clinical findings, his response to medical therapy and laser trabeculoplasty, and suggests the possibility that melanosis oculi causes secondary open angle glaucoma in patients who are predisposed to primary open angle glaucoma.

Adolescent↗
PubMed1984

Lidocaine-pancuronium bromide retrobulbar injection: experimental studies of simultaneous neural and myoneural blockage for profound akinesia.

The akinesia of the superior rectus muscle after retrobulbar administration of lidocaine was quantitatively compared to the akinesia after retrobulbar administration of a mixture of lidocaine and pancuronium bromide. Adult cats were given halothane general anesthesia and a limited orbitotomy was performed to facilitate exposure of the superior rectus muscle and its branch of the superior division of the oculomotor nerve. The superior rectus muscle was disinserted and connected to a myograph. A suprathreshold stimulus of 3 volts was then applied to the branch of the oculomotor nerve innervating the superior rectus muscle. The strength, measured in grams, of the superior rectus muscle contraction was then quantitated with the myograph. Subsequently, retrobulbar administration of the drug was given and at 10 minute intervals thereafter the suprathreshold electrical stimulus of 3 volts was reapplied to the nerve innervating the superior rectus muscle, and the strength of the contraction was recorded with the myograph. Retrobulbar administration of 0.5 cc of 2% lidocaine was compared with retrobulbar administration of a mixture of 0.5 cc of lidocaine 2% and 0.2 mg of pancuronium bromide at a dosage of 0.04 mg per kilogram. For the first 30 minutes of the experiment, each retrobulbar administration provided profound akinesia with a total absence of measurable muscular contraction, despite suprathreshold stimulation of the nerve. From 40 to 120 minutes following the retrobulbar administration, the combination of lidocaine 2% and pancuronium bromide was associated with persistent absence of measurable superior rectus contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Local↗