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Results for “EYE, ARTIFICIAL”

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At least 91 records · Page 5Linked to original sources

PubMed1998

A study of the hydroxyapatite orbital implant drilling procedure.

PURPOSE: The hydroxyapatite orbital implant has been introduced as a buried, integrated implant for use in the anophthalmic patient. The second stage of the procedure involves drilling the implant and inserting a motility peg that allows direct coupling of the artificial eye to the implant. Other authors have advocated an assessment of implant vascularity by imaging prior to drilling. We aimed to see whether our practice of drilling after a predetermined time interval without assessment of implant vascularity would result in a higher complication rate. We also aimed to determine how successful the drilling procedure was in improving both the motility and the stability of the artificial eye. METHODS: The notes of 41 consecutive patients who underwent drilling were studied to determine the time interval between implantation with a hydroxyapatite sphere and drilling, the nature of any complications and any further surgical procedures undertaken. A postal questionnaire was sent to all patients asking them to grade the motility of their implant before and after drilling, and to state whether or not there had been any improvement in the stability of their artificial eye. RESULTS: The most frequent complication encountered was extrusion of the motility peg, which occurred in 3 patients. A total of 5 patients required redrilling. There was an 80% response rate to the questionnaire. Ninety-one per cent of patients felt that there had been an improvement in the motility of their artificial eye and 76% felt that the stability of their artificial eye had been improved. CONCLUSION: Pegging of the hydroxyapatite implant improves both the motility and the stability of the artificial eye in the majority of cases. Complications are infrequent and minor. If sufficient time is allowed after implantation for full implant vascularity to occur, it is not necessary to perform imaging studies. This practice does not result in an increase in complications, and significantly reduces the expense of the procedure.

Adolescent↗

PubMed1977

Deep ocular socket reconstruction.

A technique to reconstruct totally contracted sockets forms spacious, deep ocular fornices to accommodate ocular prostheses. Fixation of the midperiphery of mucous-membrane-lined, custommade conformers to the superior and inferior orbital rims secures the posterior periphery of the conformer deep in the orbit. The method restores the normal anatomy of the ocular fornices that not only extends to the orbital rims but also penetrates deeply into the orbit along its roof and floor. The procedure contrasts with conventional, frequently unsuccessful methods of socket reconstruction that form fornices only to the superior and inferior orbital rims without extending posteriorly into the orbit. Using this technique, we reconstructed deep, spacious sockets in five patients with serious socket contracture, allowing the patients to retain cosmetically acceptable artificial eyes. The principles advocated apply to all contracted sockets.

Adolescent↗

PubMed1980

Fluorophotometry. I. Technique.

A radiometer and photomultiplier assembly was used to measure light intensities under several artificial conditions to assess the efficacy of the fluorophotometer and the technique of ocular fluorophotometer and the technique of ocular fluorophotometry. Using an artificial eye and a cat eye that had undergone vitrectomy, we found that scatter of light from the retinal surface may contribute to the fluorescence recorded.

Animals↗

PubMed2003

[Muscle pedunculated scleral flaps. A microsurgical modification to improve prosthesis motility].

Orbital implants following enucleation are able beyond all doubt to compensate volume adequately and improve artificial eye motility. In recent decades progress has been made concerning implant material. Nevertheless, in most designs wrapping with homoplastic or alloplastic materials is advocated. In this report a microsurgical concept is presented to avoid wrapping material and at the same time to improve prosthesis motility in a hydroxyapatite-silicon implant. In a retrospective study two groups of patients (15 individuals each) were compared concerning prosthesis motility 6 months after surgery. In group 1 the horizontal and vertical eye muscles were sutured cross-wise in front of the implant (as done since the introduction of this type in 1989). In group 2 autologous muscle pedunculated scleral flaps were dissected microsurgically and used to cover the anterior part of the porous hydroxyapatite component of the implant. There was a highly significant better prosthesis motility and so far no complications concerning implant coverage in this second group. The authors consider the use of muscle pedunculated sclera to be a modification to improve the cosmetic outcome which may also reduce the postoperative complication rate in enucleation surgery.

Equipment Failure Analysis↗

PubMed1977

A method to correct the contracted socket.

In four patients, rotation of the inferior tarsus around the tarsal-tendon horizontal axis caused a contracted socket with loss of lower fornix and the inability to retain an artificial eye. Exposure of the lower border of the inferior tarsus through a skin incision, separating the tarsus from the overlying orbicularis oculi muscle, and suturing its lower margin to the skin corrected the abnormality.

Anophthalmos↗

PubMed1976

Orbital prostheses.

This article presents the steps used in fabricating an orbital prosthesis. Major considerations such as selection of the spectacle frame and the artificial eye, eye alignment, and clay modeling are emphasized to ensure an esthetically acceptable prosthesis. A simple technique for construction of wax templates for fabrication of orbital prostheses in acrylic resin also was described.

Eye, Artificial↗

PubMed2001

The shape of the aging human lens: curvature, equivalent refractive index and the lens paradox.

Scheimpflug slit images of the crystalline lens are distorted due to the refracting properties of the cornea and because they are obliquely viewed. We measured the aspheric curvature of the lens of 102 subjects ranging in age between 16 and 65 years and applied correction for these distortions. The procedure was validated by measuring an artificial eye and pseudophakic patients with intraocular lenses of known dimensions. Compared to previous studies using Scheimpflug photography, the decrease of the radius of the anterior lens surface with age was smaller, and the absolute value for the radius of the anterior and posterior lens surface was significantly smaller. A slight decrease of the posterior lens radius with age could be demonstrated. Generally, front and back surfaces were hyperbolic. Axial length was measured of 42 subjects enabling calculation of the equivalent refractive index of the lens, which showed a small, but highly significant decrease with age. These new findings explain the lens paradox and may serve as a basis for modelling the refractive properties of the lens.

Adolescent↗

PubMed1981

Fitting of the dermis-fat grafted socket.

Anophthalmic orbits that reject conventional implants may accept the dermis-fat graft. The subsequent fitting of such a socket differs in many important ways from the fitting of sockets containing conventional implants. Before surgery, the ocularist should construct a custom-made scleral ring to be inserted after the operation. This replaces the standard conformer that can erode the underlying dermis. The socket must be observed carefully for any evidence of damage to the conjunctiva-dermis suture line by the ring, and the latter modified or replaced as necessary. Granulation tissue forming around the sutures uniting conjunctiva and dermis may have to be resected and cauterized. Impression molding of an artificial eye is performed five weeks after surgery. The artificial eye always requires modifications over the first six months as the graft recedes due to partial atrophy of the fat of the graft, thus deepening the socket.

Adipose Tissue↗

PubMed1999

Resolution of retinal digital colour images.

Several digital colour cameras commercially available were fitted on a fundus camera. A test target placed in an artificial eye was used for measurements of the resolution of the resulting digital images and compared to film material. The maximal target resolution of the fundus camera was 6 microm corresponding to 24 microm at the image plane. The best film material matched this closely. To avoid aliasing, the size of the digital image must be 2-3000 pixels to match this resolution. This criterium is fulfilled by present high-end digital cameras. Further development of hardware and software is needed for their introduction into clinical settings.

Color↗

PubMed1982

Prosthetic correction.

Fitting a comfortable and cosmetically attractive prosthetic device is a challenge, one which many people in the ophthalmic field seem to hesitate to undertake. Based on my experience, I provide practical guidelines for this important task. Artificial eyes which are required after enucleation are not discussed, but contact lenses and shells for disfigured blind or seeing eyes are.

Blindness↗

PubMed1984

Fast neutron treatment as an alternative to radical surgery for malignant tumours of the facial area.

Thirty one patients with very advanced tumours of the maxillary sinus were treated with fast neutrons. Tumour regressed completely in 29 (94%) and subsequently recurred in four (14%). No surgical excision of bone, skin, or nerve was required, and an artificial eye was well tolerated in cases where the eye received the tumour dose and had to be removed. Complications occurred in 10 patients, two of whom had already received radical x ray treatment. The overall duration of neutron treatment was four weeks, and admission to hospital was usually unnecessary. These results compared well with those obtained with surgery. Surgery with curative intent for even moderately advanced tumours of the facial region, particularly the paranasal sinuses, results in deformity, which is often severe and always irreversible. Even so, the cure rate is only about 35%. The high rates of tumour control and the avoidance of severe cosmetic and functional defects after fast neutron treatment make it an alternative to radical surgery in the management of malignant tumours of the facial area.

Eye, Artificial↗

PubMed2006

Variability in pupil size estimation.

BACKGROUND: The clinical estimation of pupil size and reactivity is central to the neurological assessment of patients, particularly those with or at risk of neurological damage. Health care professionals who examine pupils have differing levels of skill and training, yet their recordings are passed along the patient care pathway and can influence care decisions. The aim of this study was to determine if any statistical differences existed in the estimation of pupil size by different groups of health care professionals. METHODS: A total of 102 health care professionals working in the critical care environment were asked to estimate and record the pupil size of a series of 12 artificial eyes with varying pupil diameter and iris colour. All estimations were performed indoors under ambient lighting conditions. RESULTS: Our results established a statistically significant difference between staff groups in the estimation of pupil size. CONCLUSION: The demonstrated variability in pupil size estimation may not be clinically significant. However, it remains desirable to have consistency of measurement throughout the patient care pathway.

Analysis of Variance↗

PubMed2002

Liquid-crystal adaptive optics based on feedback interferometry for high-resolution retinal imaging.

A novel, to our knowledge, adaptive optical imaging system for high-resolution retinal imaging is described. The system is based on a feedback interferometer, in which two-dimensional output fringe intensity from a Mach-Zehnder interferometer with large radial shear is fed back, with the help of a video projector connected with a CCD camera, to an optically addressed phase-only liquid-crystal spatial light modulator. Experiments to verify the system performance have been conducted by use of an artificial eye consisting of a lens, an aberration plate, and a resolution test target. We observed that an image of the test target (mimicking a retina) blurred by the aberration plate (mimicking ocular aberrations) was successfully restored immediately after our adaptive optics system was activated.

Eye, Artificial↗

PubMed2003

[Preliminary report on primary drilling procedure at the time of hydroxyapatite orbital implant].

OBJECTIVE: To evaluate the clinical effect of the drilling and inserting a motility peg at the time of hydroxyapatite orbital implant. METHODS: After drilling and insertion of a titanium motility peg, a hydroxyapatite orbital implant was inserted in 31 consecutive patients. Of the 31 patients, 23 had been referred for primary enucleation and 8 for secondary implant surgery. The titanium-threaded sleeve was driven into the hydroxyapatite after which the titanium flat-headed peg was inserted into the sleeve before orbital implantation. The flat-headed peg was replaced with a titanium motility/support peg 3 to 7 months later. RESULTS: Follow-up ranged from 3.0 to 11.0 months (mean, 6.9 months). All patients were successfully fit with prostheses. Prosthetic motility was acceptable in each patient. 12 of 31 titanium flat-headed pegs became spontaneously and partially exposed within 3 to 7 months. There were no cases of secondary infection, implant exposure or extrusion of the motility peg. CONCLUSION: The hydroxyapatite orbital implant primary drilling procedure gives good cosmetic results with good motility of the artificial eye. It does not result in increased complications, and is an effective and efficient surgical option.

Adolescent↗

PubMed1990

Mobility implants: a review.

We present a brief review of mobility implants, their contribution, and the experiences derived after almost 40 years since the new concepts of full mobility implants were introduced. In early 1940, experiments with a new material for the making of plastic artificial eyes was also being considered for the making of orbital implants. Methyl-methacrylate (MMA) had proven inert and satisfactory for dental products. The Surgeon Generals office of the Armed Services encouraged further research and experimental work in the development of plastic eyes. The success of the new material sponsored the beginning of great expansion with new concepts for orbital implants. Through a period of more than a decade, the design and types of implants went through three stages. First, the buried implant was introduced, then the exposed integrated followed, and the buried integrated subsequently followed. The path of progress was not smooth. Theoretically correct designs and surgical procedures met unexpected practical difficulties for the ophthalmic surgeon, the patient, and the eye maker. Surgical and technical efforts were carefully reviewed to eliminate the problems encountered, only to have further unforeseen complications arise. Infections, extrusions, and migration of the implant were not uncommon. The exposed integrated implant was eventually abandoned. However, there were some extraordinary successes of mobility. A new era introduced fully buried mobility implants that were more successful. However, this procedure also produced some problems, causing infection (or allergy), extrusion, and migration. Tantalum mesh and gauze gave great promise with the inception of their use. Orbital tissue grew into the material in an astonishing way, making it possible to secure the extraocular muscles and tenons.(ABSTRACT TRUNCATED AT 250 WORDS)

Biocompatible Materials↗

PubMed1995

[Prevention of postenucleation syndrome: the hydroxylapatite silicone implant. Preliminary experimental studies and initial clinical experiences].

An orbital implant after enucleation compensates for volume deficiency and increases prosthesis motility. In the literature, however, an extrusion rate of orbital implant between 10 and 25% is reported. Since the introduction of hydroxylapatic ceramics (HAC), these numbers have been reduced considerably. The HAC, which is derived from corals, has a rough surface and requires a scleral covering for implantation. The HAC, which is made in the laboratory, can be produced with smoother surfaces, so that a homoplastic covering is no longer mandatory. A composite implant was developed to improve prosthesis motility further. This consists of artificial HAC at its anterior surface to guarantee safe tissue integration; the posterior part of the implant is manufactured from silicon rubber to create a jointlike structure in Tenon's capsule. Integration of the porous HAC in the orbital soft tissues has been tested and confirmed by animal experiments. After 30 full HAC implants and 25 composite implants, only one extrusion occurred. In all other cases, compatibility proved to be excellent; transmission of the motility to the prosthesis was moderate to good. Examinations comparing prosthesis motility and computer tomographically evaluated implant motility enabled the analysis of deficits in motility transmission of the implant for the artificial eye.

Animals↗

PubMed1994

[Bone transplantation in the orbits as a prerequisite for prosthetic management].

We report on a method of fixing orbital prostheses and artificial eyes: First the orbit is filled by cortico-spongious bone graft. Afterwards two implants are centrally located in the graft, so that the prosthesis can be kept in place by magnetic retention. The advantage of this procedure is that the implants are more stable than those located in the orbital rim.

Adult↗

PubMed1993

Evaluation of biomatrix hydroxyapatite ocular implants with technetium-99m-MDP.

Hydroxyapatite ocular implants appear to offer excellent cosmetic reconstruction with lower rates of infection and extrusion compared to other integrated implants. However, vascularization of the implant needs to be established before the artificial eye is attached to the implant. Technetium-99m-methylene diphosphonate (MDP) scintigraphy can be utilized as a noninvasive method for determining the vascularity of the hydroxyapatite ocular implants. A case is presented in which 99mTc-MDP uptake in the implant was deemed sufficient for further surgical intervention.

Durapatite↗