Biomedical subjects

H Lincoff

Publications and source records attributed to H Lincoff.

At least 37 records · Page 2Linked to original sources

PubMed1989

Giant retinal tears. Surgical techniques and results using perfluorocarbon liquids.

Three low-viscosity perfluorocarbon liquids provided an intraoperative tool during vitrectomy to manage giant retinal tears. These clear fluids have a high specific gravity (1.8 to 1.9) and are immiscible with water. In six eyes, the giant tear was less than 180 degrees; in 11 eyes, it was 180 degrees or greater. In all eyes, the tear was unfolded and the retina was flattened while the patient was supine. The perfluorocarbon liquid was aspirated and replaced by air-perfluorocarbon gas mixtures (16 eyes) or silicone oil (one eye) at the end of the operation. The retina was reattached in 16 eyes (94%), with a minimum follow-up period of 6 months. In five eyes (29%), the retina was reattached without scleral buckling. Residual droplets of perfluorocarbon liquid were observed in four patients. These new materials complement present surgical techniques for managing giant retinal tears.

Air↗

PubMed1989

Air travel with intraocular gas. I. The mechanisms for compensation.

The absolute intraocular pressure of the gas-containing eye of a rabbit fell with the fall in cabin pressure during a simulated airplane ascent but lagged behind. The lag was manifested clinically as a relative rise in transscleral pressure. The amount of lag depended on the amount of gas in the eye at takeoff. As there is no significant transfer of gas out of the eye during the ascent, the fall in absolute intraocular pressure could only be mediated by expansion of the bubble. The enabling mechanisms for expansion are choroidal compression, scleral expansion, and accelerated aqueous outflow.

Aerospace Medicine↗

PubMed1989

Air travel with intraocular gas. II. Clinical considerations.

The patient with a residual intraocular gas volume of 0.6 mL, approximately 10% of the volume of the eye, can compensate for the decrease in cabin pressure as an airplane ascends without a symptomatic rise in intraocular pressure. Larger volumes may be accommodated in aircraft that decompress to less than 8000 ft or that take off from altitudes above sea level. The patient with residual intraocular gas who experiences pain or dimness of vision in an ascending airplane can obtain relief if the cabin altitude is decreased by 2000 ft. This will require a modest adjustment in the altitude of the airplane.

Aerospace Medicine↗

PubMed1989

Irradiation of choroidal melanomas before enucleation?

The eyes of 26 patients with choroidal melanomas were irradiated before enucleation at the University Eye Clinic in Tübingen. Preoperative external beam radiation therapy (PERT) was administered between July 1980 and July 1986. Follow-up ranged from 25 months to 8 years, 4 months with a mean follow-up of 53 months. The average diameter of the tumor base was 15 mm and the height 10 mm. Before enucleation vertical stationary electron beam irradiation (10-12 meV) was applied to the tumor-containing eye and the orbit. The dose was increased during the course of the study from 12 to 40 Gy. Enucleation was performed by a technique that cauterized the vasculature before severing it and avoided maneuvers that would cause changes in intraocular pressure. The patients were reexamined between August and November 1988. Nine (34.6%) had died of metastases of melanoma, six of them during the second postoperative year; one patient was alive with metastases. Subsequent death occurred in all patients who had melanomas of epithelioid cell type (3 of 3) and in no patients who had melanomas of spindle A cell type (0 of 3). In this small series PERT had no apparent beneficial effect on the patient's life expectancy.

Adult↗

PubMed1988

Retinoschisis associated with optic nerve pits.

Stereoscopic transparencies studied with magnification and projection suggest that the retinal elevation that communicates with optic pits is frequently a schisislike separation of the internal layers of retina. Thirteen of 15 eyes with optic pits and maculopathy fit the schisis pattern. Separation of the outer layers of the retina is a secondary phenomenon that starts in the macula.

Adult↗

PubMed1987

The treatment of giant tear detachments using retrohyaloidal perfluorocarbon gases without drainage or vitrectomy.

In a pilot study, an expanding perflurocarbon gas was injected into the retrohyaloidal space for treating giant tear detachments. Using the balloon-gas procedure with a single gas injection, a bubble was obtained that was large enough to tamponade a giant tear without prior drainage of subretinal fluid or vitrectomy. The procedure was performed under subconjunctival anesthesia in order to preserve the patient's light perception, the fading of which served as a safeguard against excessive gas injection. The posterior hyaloidal membrane was only attached to the anterior flap of the tear and to the circumference of the retina anterior to the equator. The retrohyaloidal gas injection was not followed by star-fold formation or other evidence of preretinal proliferation. During the follow-up, the detached posterior hyaloidal membrane appeared to have collapsed on the anterior retina in concertina-like folds. Reattachment occurred in four of the five cases; no retina redetached during an average follow-up of 2 years.

Adult↗

PubMed1987

[A complication in gas surgery: injection of gas beneath the retina in a pseudophakic eye].

Report on an inadvertent injection of gas beneath the retina in a pseudophakic eye. The gas was injected through the pupil to tamponade a retinal break. Instead, however, it found its way under the retina, increasing the extent of the detachment. A thick, transparent membrane posterior to the intraocular lens prevented the gas from entering the vitreous space and diverted it laterally behind the iris to the ciliary body, where it penetrated between layers of the ciliary epithelium and entered the subretinal space. The gas became visible under the retina. The bullous redetachment had a mother-of-pearl-like opalescence characteristic of gas beneath the retina.

Aged↗

PubMed1986

Treating avulsed vessels with a temporary balloon buckle.

We treated nine patients with avulsed retinal vessels by first expanding a balloon in the parabulbar space to buckle the vessel temporarily and then applying a laser beam to the avulsed segment. In three patients the avulsed vessel was an artery and in six it was a vein. The avulsion was the only abnormality in three patients; in six it was combined with a retinal break, which was accompanied by a detachment in five. The balloon brought the avulsed portion of the vessel into contact with the retina and the pigment epithelium and made it receptive to laser coagulation. Flow in the vessel could be slowed or stopped while the patient was undergoing laser treatment by further expanding the balloon.

Evaluation Studies as Topic↗

PubMed1986

Morphological effects of gas compression on the cortical vitreous.

We used scanning electron microscopy to study vitreous in normal and perfluorocarbon gas-treated eyes of cynomolgus monkeys. The cortical vitreous of the normal (control) eye appeared to be a lamellar structure composed of sheets of collagen mesh. In the gas-treated eye there was shrinking and tearing of the lamellae. At six and 12 weeks after gas injection there was membrane formation at the edges of the torn lamellae.

Animals↗

PubMed1986

Gas vitrectomy in a primate model.

Total displacement of vitreous by an expanding bubble of a perfluorocarbon gas was studied in cynomolgus monkeys. The clinical observations and the gross dissection suggested that cortical vitreous might have been stripped from the retina; however, electron microscopy of frozen sections demonstrated that the collagen structure of the vitreous was compressed against the retina.

Animals↗

PubMed1986

The treatment of difficult retinal detachments with an expanding gas bubble without vitrectomy.

In a prospective study on the use of perfluorocarbon gases (CF4, C2F6, C3F8) without prior mechanical vitrectomy, 51 retinal detachments that were not suitable for scleral buckling were treated by injection of a small bubble of gas into the vitreous to form a tamponade. There were 23 patients with giant tears, 16 with posterior holes, 9 with breaks at different latitudes, and 3 in whom the gas was used for diagnostic purposes. The gases were sustained at therapeutic volumes for 10-70 days. The tears were sealed with argon or krypton laser. The overall reattachment rate was 71%. Postoperative visual acuity improved or remained the same in all patients with reattached retina. In a follow-up of 1 year-38 months there were no late complications, such as cataract, glaucoma, keratopathy, or subsequent visual deterioration.

Adolescent↗

PubMed1986

The inadvertent injection of gas beneath the retina in a pseudophakic eye.

Gas injected through the pupil to tamponade a detached retina in a pseudophakic eye inadvertently made its way beneath the retina and augmented the detachment. A transparent membrane posterior to an iris-supported lens prevented the gas from entering the vitreous and diverted it laterally behind the iris, to the ciliary body, where is dissected between layers of ciliary epithelium and entered the subretinal space.

Aged↗

PubMed1986

[Local anesthesia with accidental perforation of the eye--an acute emergency?].

A report on 3 instances of accidental injection of lidocaine into the eye. Among the immediate reactions were (1) development of corneal edema due to an abrupt rise in intraocular pressure, (2) dilatation and paralysis of the pupil, (3) decrease of visual acuity to light perception. In 2 of the patients pupillary reaction and retinal function recovered completely; the third developed a permanent field defect. The effects of intraocular injection of lidocaine, epinephrine and hyaluronidase were subsequently studied in an animal model. The corneal and pupillary reactions of the animals correlated with those of the 3 patients. The b-wave of the electroretinogram, representing the function of the internal retinal layers, was temporarily extinguished but recovered completely after 4 hours. Subsequent light and electron microscopic study of the animal retinas did not reveal any drug induced damage. Following intraocular injection of lidocaine, epinephrine, or hyaluronidase permanent damage to the retina or irreversible reduction in visual acuity was observed neither in the first 2 patients nor in the animals.

Adult↗

PubMed1986

Optic disc edema and Lyme disease.

A seven-year-old child developed a febrile rash, migratory arthritis, and neurologic signs. Three days earlier, the child had been bitten by a tick. An eye examination two months later revealed bilateral papilledema, although the cerebrospinal fluid pressure was 170 mm. The IgM antibody titer for the Ixodes dammini spirochete was 1:256. I dammini is the tick vector for the Borrelia spirochete that causes Lyme disease. The papilledema receded with treatment over a month's time, and bilateral pigment epithelial mottling at the fovea was present after one year.

Antibodies, Bacterial↗

PubMed1985

Intraocular injection of lidocaine.

Lidocaine was inadvertently injected intraocularly in three patients. In the one patient who had not received prior mydriatics, the drug caused immediate dilation and paralysis of the pupil and diminished visual acuity to counting fingers. Retinal function began to improve after four hours and both retinal and pupillary function recovered completely by 16 hours. A second patient also recovered completely. The third patient developed a permanent field defect. The effects of intraocular lidocaine were then studied in an animal model. Lidocaine temporarily paralyzed the pupil in mydriasis and temporarily extinguished the b-wave of the electroretinogram. Light and electron microscopy study of the retina revealed no damage beyond that at the perforation site.

Animals↗

PubMed1985

Results of 100 aphakic detachments treated with a temporary balloon buckle: a case against routine encircling operations.

One hundred patients with aphakic detachment were treated with temporary balloon buckles. The balloons were deflated and withdrawn after seven to 10 days. Permanent attachment depended on cryo- or laser-induced adhesions round the break. The procedure was initially successful in 79 patients. Ten retinas became detached again after the balloon was withdrawn and required a more permanent buckle. Sixty-nine retinas remained attached. The final results after additional operations were equivalent to those obtained by traditional methods, but significantly fewer complications occurred. The balloon procedure tests the validity of routinely encircling aphakic detachment.

Aphakia, Postcataract↗

PubMed1984

Perfluoropropane gas in the management of proliferative vitreoretinopathy.

Perfluoropropane (C3F8), an expanding fluorinated hydrocarbon gas, was used as an adjunct to vitreous surgery in the management of 18 patients with retinal detachment complicated by proliferative vitreoretinopathy. Ten patients had reattached retinas six months after disappearance of the gas. The average intraocular longevity of the gas in successful cases was 92 days; that in failed cases was 62.7 days. This difference was not statistically significant. However, internal retinal tamponade by longer-lasting gases appears to increase the rate of retinal reattachment in the surgical management of proliferative vitreoretinopathy.

Eye Diseases↗

PubMed1984

Intravitreal disappearance rates of four perfluorocarbon gases.

The disappearance rates of bubbles from the vitreous of rabbits were measured for four perfluorocarbon gases. The decay rate for each was found to be exponential and thus independent of the volume injected. Clinical observations indicated that the disappearance of the perfluorocarbon gases in patients also follows exponential decay, but that the half-lives are three to five times longer than in rabbits.

Animals↗