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Biomedical subjects

C L Schepens

Publications and source records attributed to C L Schepens.

At least 19 recordsLinked to original sources
PubMed1992

Long-term complications of the MAI hydrogel intrascleral buckling implant.

Seven cases in which long-term complications developed from swelling of the MAI hydrogel intrascleral buckling implant are reported herein. Micro-Fourier transform infrared spectroscopic analysis of two recovered implants demonstrated the occurrence of chemical changes leading to increased swelling. Clinical problems with the implants appeared 7 to 11 years after surgery, suggesting the need for periodic, long-term follow-up. It is possible that the present-day MIRAgel implant, which has the same chemical composition as the MAI implant, may require similar precautions.

Adolescent↗
PubMed1992

Treatment of persistent epithelial defects in neurotrophic keratitis with epidermal growth factor: a preliminary open study.

We report three patients with persistent epithelial defects in the context of neurotrophic keratopathy that healed while on treatment with topically applied, mouse-derived epidermal growth factor (m-EGF). The clinical course of these patients was striking and suggests that EGF may have a potential role in the treatment of persistent epithelial defects in subjects suffering from neurotrophic keratitis.

Administration, Topical↗
PubMed1992

Retinal detachment after cataract surgery. Surgical results.

The authors studied the results obtained by the Retina Associates in 376 eyes of 361 patients operated on for retinal detachment associated with aphakia or pseudophakia with a postoperative follow-up of at least 6 months. All eyes underwent scleral buckling. The series included 103 eyes with aphakia, 17 eyes with iris-fixated intraocular lens, 111 eyes with anterior chamber (AC) IOL, and 145 eyes with posterior chamber (PC) IOL. The overall success rate for retinal detachment was 93%, without significant difference among the different groups. The aphakia and PC IOL groups had significantly higher prevalence (63% and 60%, respectively) of visual acuity equal to or better than 20/40 compared with the AC IOL group (33%). The prevalence of postoperative corneal edema in the AC IOL group was significantly higher than in the aphakia and PC IOL groups. Preoperative vitreous hemorrhage, large retinal breaks, posterior retinal breaks, total retinal detachment, proliferative vitreoretinopathy, and the need for performing a closed vitrectomy were significant factors in predicting ultimate failure.

Aged↗
PubMed1992

Retinal detachment after cataract surgery. Predisposing factors.

The authors studied the characteristics of 376 eyes of 361 patients with primary retinal detachment (RD) and surgical aphakia (103 eyes) or pseudophakia (273 eyes). Of the pseudophakic eyes, 17 had an iris-fixated intraocular lens (IOL), 111 had an anterior chamber (AC) IOL, and 145 had a posterior chamber (PC) IOL. Of the PC IOL cases, 48 (33%) had undergone YAG capsulotomy, and 46% of them developed RD within 6 months after capsulotomy. The frequency of no breaks found in pseudophakic RD (15%) was significantly higher than in RD with simple aphakia (5%). The most frequent reasons were incomplete fundus view due to a small pupil in the iris-fixated (83%) and the AC (44%) groups, and cloudiness of capsular remnants in the PC group (78%). In pseudophakic RD, sizable single tears, located more posteriorly than in RD with simple aphakia, were frequent. The authors speculate that in pseudophakic RD the retinal breaks may resemble those noted in phakic RD.

Aged↗
PubMed1990

Vitreous changes and macular edema in central retinal vein occlusion.

The condition of the posterior vitreous was determined in 56 eyes with central retinal vein occlusion (CRVO). Using a life-table analysis, it was studied in 56 eyes. The incidence of posterior vitreous detachment (PVD) in the CRVO eyes at the first vitreous examination did not differ significantly from that in 64 age-matched control eyes. However, the incidence of PVD in CRVO eyes increased from 39.3% at the first vitreous examination to 58.5% after 6 months, and to 69.6% 1 year from the examination. The incidence of PVD in CRVO eyes during follow-up was statistically higher than that of the controls (P = .009). The incidence of PVD after the first vitreous examination was significantly higher in eyes with hemorrhagic retinopathy than in eyes with venous stasis retinopathy (P = .04). In the 34 eyes with macular edema, the edema lasted significantly longer in those with vitreomacular attachment (VMA) at the first examination than in those without VMA at this time (P = .02). VMA may play an important role in the pathogenesis and chronicity of macular edema in CRVO.

Adult↗
PubMed1989

Subretinal hemorrhage in atrophic age-related macular degeneration.

In eight eyes of eight patients we retrospectively studied the outcome of subretinal hemorrhage occurring in areas of atrophy of retinal pigment epithelium and choriocapillaris secondary to age-related macular degeneration. These patients were followed up for one to 20 months after the initial appearance of the hemorrhage. No subretinal new vessels were associated with these hemorrhages, which resolved over one to 15 months. Our findings indicated that hemorrhages occurring within areas of atrophy are not necessarily associated with subretinal new vessels, and that this type of hemorrhage has a good prognosis for resolution.

Age Factors↗
PubMed1989

Importance of the vitreous in young diabetics with macular edema.

The authors assessed retrospectively the clinical records of 80 patients (137 eyes) with diabetic retinopathy who were 50 years of age or younger and who had undergone a vitreous examination. The group comprised 53 patients (91 eyes) with macular edema and 27 patients (46 eyes) without macular edema. Vitreous studies using the El Bayadi-Kajiura lens determined whether the posterior vitreous was attached to the retina in the macula. Forty (42.1%) of 91 eyes in the edema group and none (0%) of the 46 eyes in the nonedema group had a detached posterior vitreous. This difference was statistically significant, indicating that young diabetic patients with macular edema have a significantly higher rate of posterior vitreous detachment than those without macular edema.

Adolescent↗
PubMed1989

Argon green laser treatment of peripapillary choroidal neovascular membranes.

Of 27 eyes with peripapillary choroidal neovascular membranes (PPCNM), 17 (63%) had age-related macular degeneration and ten (37%) were idiopathic. PPCNM were treated in 25 eyes using the monochromatic green argon laser. Two eyes were untreatable. After an average follow-up of 37.7 months, successful closure of the choroidal new vessels was obtained in 23 eyes (92%), and visual acuity was stabilized or improved in 20 (80%). Seven eyes (28%) had recurrences; in four, the new vessels extended into the macula. Post-treatment, three eyes ultimately had dry macular scars, and one had an exudative macular scar. Of these four eyes, only the one with a dry macular scar showed visual improvement. No treated cases showed arcuate scotoma.

Age Factors↗
PubMed1989

Can chronic bulbar hypotony be responsible for uveal effusion? Report of two cases.

We describe two patients with a unilateral uveal effusion syndrome characterized by spontaneous ciliochoroidal and retinal detachment, shallow anterior chamber, poorly reactive pupil, and bulbar hypotony. A space-occupying substance of high molecular weight (sodium hyaluronate), injected into the anterior chamber, raised the intraocular pressure of these patients to 24 mm Hg. Within 24 to 72 hours the uvea flattened, and later the retina settled completely. Satisfactory clinical stability has continued in the follow-up period. Because a rheologic study of the aqueous humor revealed hyposecretion and hypotony in the apparently unaffected fellow eye, it is suggested that a primary bulbar hypotony can trigger a uveal effusion syndrome in an otherwise normal-sized eye with no structural abnormality.

Aged↗
PubMed1988

Visual results with low-vision aids in age-related macular degeneration.

We reviewed the records of 61 patients with age-related macular degeneration who had an exudative or a dry macular scar and who had received low-vision rehabilitation. Exudative scars resulted from the natural course of sub-retinal new vessels, and dry scars from successful photocoagulation to the new vessels. Low-vision aids consisted of high-power positive lenses. Eyes were divided into three groups according to their distance visual acuity before using low-vision aids: Group 1, 20/100; Group 2, 20/200 to 20/300; and Group 3, 20/400 or poorer. The print size resolution on the Rosenbaum pocket vision screener and power of the low-vision aid in each group were compared for the eyes having exudative scars and those with dry photocoagulation scars. In Groups 2 and 3, eyes with dry macular scars reached a similar resolution of print size but with significantly (P less than .01) lower-power visual aids than eyes with exudative macular scars. In Group 1, eyes with dry macular scars achieved a better print size resolution using significantly (P less than .01) lower-power visual aids than eyes with exudative scars.

Aging↗
PubMed1988

Unusual central chorioretinitis as the first manifestation of early secondary syphilis.

Three young, otherwise healthy patients had a similar picture of unilateral central chorioretinitis associated with severe visual loss. Fluorescein angiography disclosed diffuse leakage under the neurosensory retina in the posterior pole, associated with multifocal areas of staining along the retinal vessels. Systemic examination showed a positive fluorescent treponemal antibody absorption test and a sharp increase in VDRL titers, indicative of active secondary syphilis. The patients responded dramatically to penicillin treatment, with visual recovery and resolution of the fundus lesions.

Adult↗
PubMed1988

A new solid-state, frequency-doubled neodymium-YAG photocoagulation system.

We have developed a solid-state laser system that produces a continuous green monochromatic laser beam of 532 nm by doubling the frequency of a neodymium-YAG laser wavelength of 1064 nm with a potassium-titamyl-phosphate crystal. Photocoagulation burns of equal size and intensity were placed in two rabbit eyes with the solid-state laser system and the regular green argon laser system, respectively, using the same slit-lamp mode of delivery. Histologic findings of lesion sections revealed no important differences between the two systems. In theory, the longer wavelength of the solid-state laser offers the advantages of less scattering in ocular media, higher absorption by oxyhemoglobin, and less absorption by macular xanthophyll than the 514-nm wavelength of the regular green argon laser. The solid-state laser has impressive technical advantages: it contains no argon-ion gas tube that wears out and is expensive to replace; it is much more power efficient, and thus considerably smaller and compact; it is sturdier and easily movable; it does not require external cooling; it uses a 220-V monophasic alternating current; and it requires little maintenance.

Aluminum↗
PubMed1988

Local ocular hypothermia in experimental intraocular surgery.

Local ocular hypothermia was evaluated in experimental open sky vitrectomy, closed vitrectomy, and anterior chamber irrigation and aspiration in 40 albino rabbits (80 eyes). The irrigating balanced salt solution was used at room temperature in control eyes and was cooled to 7 degrees C in experimental eyes. Experimental eyes demonstrated less intraocular bleeding volume, less fibrin production, and less postoperative inflammation. No detectable tissue intolerance to hypothermia was observed on short- or long-term follow-up.

Animals↗
PubMed1988

The role of the vitreous in diabetic macular edema.

The authors assessed retrospectively clinical records of 76 patients (125 eyes) 60 years of age or older with diabetic retinopathy who had undergone a vitreous examination. The groups consisted of 105 eyes (63 patients) with macular edema and 20 eyes (13 patients) without macular edema. Vitreous studies were done using the El Bayadi-Kajiura lens to determine whether or not the posterior vitreous was attached to the retina in the macula. Twenty-one of 105 eyes (20.0%) in the edema group and 11 of 20 eyes (55.0%) in the no-edema group had a detached posterior vitreous. This difference was found to be statistically significant, indicating that diabetic cases without macular edema have a significantly higher rate of posterior vitreous detachment than those with macular edema. This study demonstrates that the vitreous may play a role in diabetic macular edema.

Aged↗
PubMed1988

Treatment of small choroidal melanomas with photocoagulation.

Seventeen eyes with small choroidal melanomas presumed to be malignant were photocoagulated. The melanomas measured 7 to 15 mm at the tumor base and 2 t0 5 mm thick. First, photocoagulation using the green argon laser was aimed at closing the choroidal vascular supply of the tumor. In a second stage, tumor tissue was destroyed using the red krypton laser for confluent burns of long duration. Such treatment was supplemented by cryotherapy in peripherally located tumors or whenever photocoagulation alone did not result in tumor regression. Photocoagulation alone was used in ten eyes and combined wih cryotherapy in seven. After an average follow-up of 42 months, marked tumor regression was achieved in 12 eyes and some tumor regression in two. Tow eyes ultimately required proton beam irradiation, and one eye was enucleated. No metastasis occurred during follow-up.

Aged↗
PubMed1988

[A universal laser for intraocular treatment].

The creation of a single apparatus incorporating the different lasers applicable to intraocular pathology derives from the idea of possessing the means, with one device, of objectively comparing the effects and parameters of various lasers in order to pursue a more precise line of treatment. This has led to our fabrication of the universal intraocular laser. The word universal means the ability of the machine to act on each kind of intraocular tissues with all of the various infrared or other-colored radiations, as well as with different modalities. The unit is transportable. It only requires a source of electric power (110 or 220 V) and includes an independent cooling system. The Nd: YAG laser has selectable operating parameters: pulsed or continuous excitation, Q-switched or mode-locked mode, mirror or fiber optic transmission. It is used also as the basic system of the coloured module. The colour module can provide the three clinically useful radiations: green, red, yellow. The green (532 nm) is obtained by transmission of the I.R. beam brought a birefringent crystal (KTP). Red (650 nm) and yellow (575 nm) come from two incorporated dye lasers excited by the green radiation.

Equipment Design↗
PubMed1988

Digoxin cannot account for the reported association of EKG abnormalities and rhegmatogenous retinal detachment.

The prevalence of cardiovascular disease (by EKG criteria) in patients with rhegmatogenous retinal detachments has been reported to be more than four times that found in age-matched controls. Adhesion between the retinal pigment epithelium (RPE) and the photoreceptors is facilitated by RPE transport. Because RPE transport is driven by a Na-K ATPase, it has been suggested that the correlation of EKG abnormalities and retinal detachment may be due to clinical use of digoxin, a Na-K ATPase inhibitor frequently given to patients with cardiovascular disease. The prevalence of EKG abnormalities in 299 consecutive patients with primary retinal detachment is about the same as that reported previously. However, 92% of these patients with EKG abnormalities did not take digoxin. Therefore, clinical use of digoxin cannot account for the reported association of EKG abnormalities and rhegmatogenous retinal detachment.

Cardiovascular Diseases↗