SEARCH · PubMed Health

Results for “EYE, ARTIFICIAL”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

PubMed2001

[Initiative report of the hydroxyapatite orbital implant drilling procedure].

OBJECTIVE: To evaluate the clinical effect of drilling procedure following the hydroxyapatite orbital implantation. METHODS: From February 1996 to April 2000, 146 consecutive patients who received hydroxyapatite orbital implant were drilled and inserted a motility peg 6 to 16 months after hydroxyapatite implantation. Among them, there were 97 males and 49 females, aged from 18 to 60 years old, of the 146 motility pegs, 36 were sleeved pegs and 110 were nonsleeved. Goldman visual field analyzer was applied to measure the degree of artificial eye's movement before and after drilling. RESULTS: Followed up for 1 to 40 months, no secondary infection occurred. The mobility of the prosthesis increased from (18.7 +/- 3.8) degrees preoperatively to (42.3 +/- 3.7) degrees postoperatively. CONCLUSION: The delayed drilling procedure and motility peg insertion improve the range of movement and the sensitivity of the artificial eye with a low rate of complications.

Adolescent↗

PubMed2003

[Development of formulation of hipromellose eye drops (artificial tears)].

The task of this research work was to develop a formulation of hipromellose ophthalmic preparation by determining optimal composition of active ingredients and excipients. Aqueous solution of hipromellose 1% and sorbitol 4.5% was prepared with addition of phosphate buffer (pH 7.05) and preservative cetrimide 0.01%. Sterile filtration was used for solution sterilization. Polimeric membrane prefilters of 1 microm, 0.45 microm and 0.22 microm pore size were employed as sterilizing filter. It is recommended to increase the temperature up to 35-38 degrees C for more efficient filtration of the solution. Quality parameters and analytical methods for quality control have been developed to control the quality and to evaluate the stability of hipromellose eye drops during their storage for 24 months. The obtained results confirmed the sterility and stability of hipromellose eye drops for the period of two years.

Anti-Infective Agents, Local↗

PubMed2002

Contracted anophthalmic socket repair.

PURPOSE: The aim of this paper is to describe a simple method for severely contracted anophthalmic socket repair in which a silicone sphere is used as an expander for widening and deepening severely contracted conjunctival sacs. PATIENTS AND METHOD: This method was used in five patients. Each patient had undergone previous operations but they could not wear artificial eyes and there was no hope of performing any other type of surgical procedure successfully. In our surgical method, the severely contracted conjunctiva is cut deeply at the desired level of the upper and lower eyelid fornix. A certain amount of scar tissue is excised and a silicone sphere is placed under the eyelids. The eyelid margins are sutured to each other with a double-running nylon suture. After four months, the eyelid fissure is opened and a special round-shaped artificial eye is inserted. The original silicone sphere is used as an expander in the evenings during the next two or three months. RESULTS: This procedure was used successfully in four of the five cases. In one case the silicone sphere was lost and cicatrization reoccurred. The longest follow-up time is now five years, the shortest, one year. CONCLUSION: Using a silicone sphere as an expander can be an alternative surgical method for contracted anophthalmic socket repair. The main advantage of this method is its simplicity. In order to use this procedure, good cooperation between doctor and patient is essential.

Adult↗

PubMedDate not supplied

[Resistance to blindness and frequency-contrast characteristics of the eye with artificial lens].

Contrast sensitivity of vision was examined by the frequency-contrast characteristics method (FCC) and vision resistance to glare studies with Niktoskop equipment in 48 patients with artiphakia. FCC was estimated from the curve shape as well as from the mean threshold contrast in all space frequencies. Blindness resistance was assessed from the period of mesopic vision acuity recovery (MVAR) up to 0.3 diopters after the glare flash. The group included 28 patients with iris clips lenses and 20 with posterior-chamber lenses. Patients with vision acuity of 0.8-1.0 diopters were referred to the first and those with vision acuity of 0.5-0.7 diopters to the second category. The mean threshold contrast, whose normal value is 8.0 +/- 0.7 percent, was drastically elevated 3 months after surgery in all the patients and only in a year normalized in the first-category patients with iris clips lenses or posterior-chamber lenses after posterior chamber dissection. Blindness resistance of patients with intraocular lenses was on the whole worse than in normal eyes: MVAR was by 26.2 +/- 0.7 percent higher than the normal value and normalized to reach 29.0 +/- 0.6 sec only in a year in the first-category patients with posterior-chamber lenses whose posterior capsule was not dissected. Therefore, FCC and MVAR values depend on the end vision acuity and type of intraocular lens and are on an average better after implantation of posterior-chamber lenses and not of iris clips lenses.

Contrast Sensitivity↗

PubMedDate not supplied

An artificial compound eye for stereoendoscopy.

A scanning endoscope has been designed with the ability to both project three-dimensional images and provide precise measurements of internal structures. This is beneficial for minimally invasive surgery, where surgeons suffer from a lack of depth perception, limited field of view, and the absence of a reference frame for dimensional measurements. Borrowing from the insect compound eye, the design uses an array of prisms, each facing a different direction but with overlapping fields of view. The prisms redirect their respective images normal to a fibre optic imaging plane and are individually controlled by electro-chromic shutters. The device thereby retains the ability to scan in multiple directions without mechanical parts and uses only a single camera. Comparison of the overlapping images with known prism positions allows for the calculation of absolute coordinates. Results from large-scale models show that the technology is plausible, and fabrication methods for a smaller device are discussed.

Depth Perception↗

PubMed2005

[Comparison on morphology and ultrastructure of two kinds of myopic models].

OBJECTIVE: To study the possibility of inducing refractive errors by opening the mouse (C57BL/6J) eye artificially after birth and explore the difference in pathogenic mechanism in form-deprivation myopia by analyzing the histological changes of the animal eyes. METHODS: 4-day-old mice (n = 13) was undergone 10-day monocular artificially opened period till the opposite eye was natural open. Another group 12-day-old mice (n = 13) were raised with monocular suture of eyelid for 7 days. Age-matched untreated mice were used as control. Retinoscopic refraction was performed subsequently. Animals were sacrificed and the eyes enucleated at the end of the experiment. The axial length and weight of the eyes were measured and the sections of the eyes were also observed by light and electron microscope. RESULTS: All eyes treated with two methods showed significant development of myopia compared with the contralateral eye. The axial length was elongated in form deprived eyes, but it was shortened in artificially opened eyes; no change in the weight of eyeball was found in form deprived eyes, but it was reduced in artificially opened eyes when compared with corresponding fellow eyes. Under light microscope, there is no significant histological difference observed in the eyes treated with two methods. Under electron microscope, rod outer segment in form deprived eyes was inordinate and the phagosomes containing fractions of the membrane disc of outer segment were remarkably decreased. No significant changes of photoreceptor were demonstrated in artificially opened eyes. CONCLUSION: The means of artificially opening eyelid can induce myopia in the mouse and the method may be useful to establish myopia animal model.

Animals↗

PubMed1998

Influence of amount and changes in axis of astigmatism on retinal image quality.

We measured retinal image quality in astigmatic eyes, using the double-pass technique. We analyzed the influence of the amount of astigmatism and changes in axis of astigmatism on the eye's optical performance. Different amounts of astigmatism were obtained by variation of the cylindrical power of a lens situated in front of the eye, between 0.25-diopter (D) overcorrection and 1-D undercorrection at intervals of 0.25 D. Changes in the axis of astigmatism were obtained by rotation of the lens, which neutralizes the astigmatism in an angle of +/- 10 degrees at 5 degrees intervals. The results show the decrease in retinal image quality and the increase in the degree of image astigmatism obtained when the amount of astigmatism increases or the angle between the lens and the eye axis is other than zero. In general, the largest variations correspond to when the astigmatism changes from 0 to 0.25 D or when the axis changes from 0 degree to +/- 5 degrees. The reduction in optical performance is smaller in living eyes than in an eye model or in an artificial eye. The aberrations present in the living eye reduce the relative loss of retinal image quality introduced by astigmatism.

Adult↗

PubMed2004

[Eye socket reconstruction with free radial forearm flap in anophthalmic orbital syndrome and contracted eye socket].

OBJECTIVE: To assess the effect of eye socket reconstruction with free radial forearm flap. METHODS: Reconstructive procedures were performed in 7 patients underwent orbital exenteration for malignant tumors and in 9 patients underwent enucleation and postoperative irradiation of the orbit for the treatment of retinoblastoma. These patients were suffered from anophthalmic orbital syndrome and contractive eye socket. A microvascular surgical technique with a free radial forearm flap was adopted. Hydroxyapatite implant was inserted as an intraorbital implantation. RESULTS: All patients were followed up for 6 months to 5 years and good cosmetic results were obtained. A large eye socket was achieved permanently. Artificial eye could be fitted with satisfactory results. CONCLUSION: Free radial forearm flap transplantation offers a useful option for the treatment of anophthalmic orbital syndrome.

Adolescent↗

PubMed1990

Prosthetic substitution for fingernails.

The loss of a fingernail is remarkably disturbing to many patients. Despite all efforts, surgical methods of replacement have not proven to be very satisfactory. Like artificial eyes, techniques for making an artificial fingernail of good likeness have been available for many years. The problem has been a satisfactory method of attaching the artificial fingernail to the digit and eventually that of making the artificial nail sufficiently thin. While no perfect solution exists, the development of a "submini" digital prosthesis that covers only the distal phalanx offers the best available solution. Only if the prosthesis is custom developed and fabricated to the very highest standards will the potential be realized. Repair will be required occasionally, so assured availability of prompt and reliable maintenance services is most important. When there has been loss of tissues from the distal phalanx, the prosthesis can also help with that problem. Finally, the prosthesis has the advantage of inflicting no scars or other irreversible measures.

Amputation, Traumatic↗

PubMedDate not supplied

Ocular prosthesis in children--clinical report.

Children and adolescents are particularly susceptible to injuries because of their fearless manner of play and their athletic immaturity due to which irreparable trauma to the eye is very commonly seen. Glaucoma is another common cause for eye loss in children. The loss of an eye causes disfigurement of the face due to which the children become emotionally weak and conscious and avoid taking part in social events, which in turn causes anxiety, stress and depression at an early age in life. Recovery after the loss of an eye requires an adjustment to monocular vision and improvement of the appearance with the use of artificial eyes carefully prepared to match the remaining natural eye. The custom made ocular prostheses are very comfortable and help children improve their appearances, which in turn, encourages them to build up their self-confidence to return back to their social life.

Adolescent↗

PubMed1995

Three-phase bone scintigraphy of hydroxyapatite ocular implants.

Hydroxyapatite ocular implants are replicas of lamellar bone tissue derived from the exoskeleton of a reef-building coral by a hydrothermal chemical exchange reaction. Attached to the eye muscles, they act as a passive framework for fibrovascular ingrowth and can be drilled to hold the visible part of the artificial eye and allow synchronous eye movement. Fibrovascular ingrowth has to be confirmed by bone scintigraphy before the drilling procedure. This study monitored the vascular ingrowth into the implant in ten patients over 12 months to establish a clinically feasible imaging protocol. Tracer accumulation was monitored visually and quantitatively in dynamic and single-photon emission tomography (SPET) scans after the intravenous administration of 600 MBq of 99mTc-DPD. The implants showed no tracer accumulation in the arterial or blood pool phase. Accordingly, dynamic scintigraphy can be omitted from the imaging protocol. Delayed tracer accumulation appeared no earlier than 2 and no later than 6 months after surgery. Planar scintigraphy is not recommended as high-resolution SPET is necessary to separate the implant from the surrounding bone. We conclude that imaging can be confined to high-resolution SPET 3 h after tracer injection, no earlier than 3 months after surgery. The vascularized hydroxyapatite orbital implant is an important in vivo model for bone-seeking agents to study their uptake kinetics independently of any soft tissue and bone disease. Our results provide evidence that in normal bones the chemical absorption of 99mTc-DPD into the crystalline structure of hydroxyapatite is the only quantitatively relevant uptake mechanism.

Diphosphonates↗

PubMed2002

Measuring higher order optical aberrations of the human eye: techniques and applications.

In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia) and higher order aberrations (coma, spherical aberration, etc.). We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45 degrees and 90 degrees. We used a device known as the Hartmann-Shack (HS) sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE) of less than 0.1 micro m for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5 degrees for the axis. This precision is sufficient for customized corneal ablations, among other applications.

Corneal Topography↗

PubMed1999

[Clinical practice of spherical allogeneic biological membranous implant in the eye socket].

OBJECTIVE: To investigate the effect of implantation of spherical allogeneic biological material implant after eyeball enucleation. METHODS: A spherical allogeneic biological material implant was implanted in the eye socket after eyeball enucleation in 50 cases including stage I in 48 cases and stage II in 2 cases. RESULTS: After operation, the motility of installed artificial eyes was good in 49 cases, the orbit and eyelids were full in all the cases. In the follow-up of 4 - 24 months (mean, 8 months), the conjunctival wound and muscular tissue were adherent firmly to the biological material, and there were no postoperative infection, no dislocation and shift of the implant. CONCLUSION: The spherical allogeneic biological membranous implant is an ideal material for the implantation in the eye socket after enucleation.

Adolescent↗

PubMed1984

Comparative study of bacterial and fungal floras of contracted sockets and fellow eyes.

Through studying 50 contracted sockets, our observations showed that generalized and gross contractions were the most common. The main cause of loss of eyes was trauma. No correlation was observed between the cause of eye loss, type of surgery done, duration of eye loss, and the type of the socket. Staphylococcus aureus was the most common bacterial pathogen followed by Pseudomonas aeruginosa. Pathogens were encountered more commonly in the sockets wearing artificial eyes, a majority of which carried the same organisms. Staphylococcus epidermidis was seen most frequently in the fellow eyes. Fungal flora of the contracted sockets did not differ from that of the fellow eyes.

Adolescent↗

PubMed2005

Synthetic hydroxyapatite-based integrated orbital implants: a human pilot trial.

PURPOSE: Orbital implants are used as fillers following enucleation or evisceration surgeries to replace the lost volume for better cosmesis and motility of the artificial eye. Over the last decade porous hydroxyapatite (HAp) implants derived from the naturally occurring corals, are increasingly used. Recently synthetic HAp-based implants have been introduced. After fibrovasculrisation they have the added advantage of being directly integrated with the artificial shell, thereby increasing the motility to a great extent. The current study, evaluated the efficacy of two different models of synthetic HAp with 75% porosity and pore sizes ranging from 100 to 300 mm. METHODS: Synthetic HAp powders were prepared with a novel wet chemical route. Two models of porous orbital implants with the characteristic designs for both evisceration and enucleation surgery were developed, characterised and implanted to consecutive 25 human subjects, 17 following evisceration, and 8 following enucleation. The postoperative performances of these implants were evaluated in respect to the degree of volume replacement (implant + prosthesis), presence/absence of lagophthalmos and lower eye-lid laxity, status of socket and fornices. Magnetic resonance imaging assessed the stability of the implants within the socket and progressive fibro-vascularisation within the porous scaffold as a function of time. Finally, motility of the implants as well as the prostheses (horizontal movements by Lister Perimeter) and subjective cosmetic results (qualitative) were also evaluated. RESULTS: During the 2.5 years of follow-up study, no significant postoperative complications were noticed. One case, showed an anterior implant exposure of 3-4 mm, and was managed with donor scleral patch graft and one case of conjunctival thinning was corrected by re-suturing the conjunctival dehiscence. Fourteen of the 25 patients had a very good movement of the prostheses (> 20 degrees horizontal movement) and the other 11 patients had a fair motility (10 - 20 degrees). The degree of volume replacement (with prosthesis) was found to be very good in 21 patients and fair in other 4 patients. All patients reported cosmetic satisfaction. CONCLUSION: Synthetic HAp-based integrated orbital implants with this modified design were found clinically safe and cosmetically acceptable.

Durapatite↗

PubMed1987

Simple pointspread retinoscope suitable for vision screening.

A simple pointspread retinoscope and method of retinoscopy are described which use optical principles similar to those of photoretinoscopy or static photographic skiascopy. In this instrument the degree of defocus of an eye is estimated from the disappearance of the bright fundal reflex or "crescent" in the eye of the subject when the distance between the light source and the eye of the observer is increased systematically. The instrument is particularly suitable for large scale screening efforts because it is easy to use and can be constructed from inexpensive materials. The pointspread retinoscope was calibrated against an artificial eye of known defocus. Additionally, results from pointspread retinoscopy were compared against meridional photorefractive data from a sample of infants and young children, and a significant correlation was found to exist between measurements made by the two methods.

Child↗

PubMed1971

The Florida retinal densitometer.

1. In Part I the principles of reflexion densitometry are discussed in relation to the measurements of visual pigments in man.2. In Part II the new Florida densitometer is described in some detail, and records are shown of the instrument's performance with pigment in equilibrium or changed by bleaching.3. With an artificial eye the fluctuations are of the order to be expected from quantum noise and limit the precision of one measurement to 0.0035 of ;double density' which corresponds to some 2% of total pigment.4. Part III treats of the reliability and significance of the measurements in living man. It needs ten repeated measurements to attain the reliability of 1 with the artificial eye.5. The measuring light used bleaches cone pigments by 0.4% in the 6 sec required to make a measurement.6. The interpretation of the measurements is briefly discussed.

Densitometry↗

PubMed1979

Management of the eye socket in cancer of the paranasal sinuses.

There are several basic techniques for obtaining acceptable closure of the orbital defect following exenteration. The approach to reconstructing a socket in the method chosen should be the one that gives the best cosmetic result while not compromising the surgical excision and the possibility of cure. Few surgeons have attempted to correct the deformity of orbital exenteration so that an artificial eye can be worn. We have found that approximately 20% of those patients undergoing radical ablation of the orbit quality for simultaneous reconstruction of the eye socket. The technique of a cheek-eyelid-conjunctiva flap allows for immediate reconsturction of the eye socket and the fitting of a prosthesis.

Eye, Artificial↗