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Biomedical subjects

D W Vastine

Publications and source records attributed to D W Vastine.

At least 19 recordsLinked to original sources
PubMed1991

Clinical assessment of corneal hydration control in Fuchs' dystrophy.

The diagnosis and monitoring of Fuchs' disease is typically based on information obtained from patient symptoms and a slitlamp examination. Although this clinical information provides a basis for diagnosis, it does not give a quantitative method for charting the progression of the disease systematically or a reliable basis for predicting the cornea's capacity to remain transparent after stress (e.g., cataract extraction). However, it is possible to quantify overall corneal hydration control by inducing corneal swelling and then monitoring the deswelling rate expressed as percent recovery per hour (PRPH). We have tested subjects with Fuchs' dystrophy and found that the PRPH provides a reasonable estimate of corneal hydration control. Unfortunately, the PRPH procedure involves considerable time and technical assistance and therefore is not convenient for clinical practice. In this report, we document the results of an initial effort to explore the relations between PRPH and six clinical measures consisting of five biomicroscopic indices and a subjective synthesis of clinical information called the probability of decompensation (POD) based on these indices. PRPH was significantly related to striae (p less than 0.001), stromal haze (p = 0.025), microcysts (p less than 0.001), and the POD (p less than 0.001) and not significantly related to guttae (p = 0.252) or Descemet's folds (p = 0.185). An empirically weighted predictor of PRPH was constructed from a statistical analysis of five slitlamp assessments and age. This approach for synthesizing clinical information produced a result at least as good as that obtained from the POD summary. These results show an important link between a quantitative laboratory assessment of corneal function and a clinical evaluation of corneal status and suggest that with continued refinement, clinical assessment may provide more quantitative information on Fuch's dystrophy and other diseases that affect corneal status.

Adult↗
PubMed1989

Removing the stableflex intraocular lens during penetrating keratoplasty.

Closed-loop, semiflexible anterior chamber intraocular lenses, particularly the Stableflex lens, have been increasingly associated with corneal decompensation. Due to the formation of synechiae around the haptics in the angle, such lenses can be difficult to remove during penetrating keratoplasty. We describe a technique for the safe removal of the Stableflex intraocular lens.

Corneal Transplantation↗
PubMed1986

Chronic Propionibacterium endophthalmitis after extracapsular cataract extraction and intraocular lens implantation.

We studied six cases of chronic, indolent intraocular inflammation that occurred after extracapsular cataract extraction and posterior chamber intraocular lens implantation. The inflammation was characterized by a delayed onset, and in three cases had the clinical appearance of a granulomatous iridocyclitis. Cultures of intraocular specimens obtained from six eyes yielded Propionibacterium; five yielded P. acnes. Pleomorphic gram-positive bacilli consistent with Propionibacterium were identified in cytologic or histopathologic studies in four of the six culture-positive cases. After surgical and medical therapy, the inflammation resolved. Postoperative Propionibacterium endophthalmitis may masquerade as a chronic iridocyclitis.

Aged↗
PubMed1985

Conjunctival transplantation. Autologous and homologous grafts.

Autologous conjunctival transplants have been used successfully for restoration of damaged ocular surfaces. Homologous (allogeneic) conjunctival grafts have been explored less systematically. We developed a nonhuman primate model for comparison of autologous and homologous conjunctival transplantation in order to assess the clinical viability and immunopathologic characteristics of these grafts. Autologous or homologous grafts were performed in nine adult rhesus monkeys. Both autologous and homologous grafts were compared for clinical viability and immunopathologic change. Clinical results suggest that, although homologous grafts incited a greater inflammatory and scarring response, there was minimal graft shrinkage and a normal surface epithelium. Immunopathologic studies using laminin, bullous pemphigoid antigen, and fibronectin indicate that, despite the increased inflammatory response seen in homografts, the epithelial surface is normal. With our increasing ability to modulate the immune response, conjunctival homografts may play a role in restoration of the ocular surface.

Animals↗
PubMed1983

Stripping of Descemet's membrane associated with intraocular lens implantation.

Stripping of Descemet's membrane (DM) occurred during intraocular lens implantation in three patients. We repositioned and anchored DM with an intracameral air bubble and through-and-through No. 10-0 nylon sutures. The favorable visual results achieved in cases of large, scrolled, nonplanar detachments reinforce the advantage of surgical repositioning. Descemetopexy with reverse through-and-through sutures in a "closed system" is recommended.

Aged↗
PubMed1983

Corneal change accompanying orthokeratology. Plastic or elastic? Results of a randomized controlled clinical trial.

Effects of orthokeratology on refractive error, visual acuity, and corneal curvature were monitored on two randomized comparison groups for 364 days of lens wear and 95 days of follow-up after lens wear was discontinued. Approximately 36% of the treatment group compared with 13% of the control group had 1 diopter or more change in refractive error; however, after lens wear was discontinued, there was substantial remission and differences between the groups were small. Although there was a positive correlation between the amount of change during lens wear and the persistence of change after discontinuation, neither the magnitude of persistence nor differences between groups were clinically important. The lack of persistence indicates that the cornea is either highly elastic or has some other memory mechanism. We conclude that orthokeratology produces modest reductions in myopia; however, the effect will not persist without continued lens wear and therefore is of limited clinical value in permanently reducing myopia.

Adaptation, Ocular↗
PubMed1983

The Berkeley Orthokeratology Study, Part II: Efficacy and duration.

Relative efficacy of orthokeratology (OK) was evaluated by assessing changes in refractive error, visual acuity, and corneal curvature in 31 treated and 28 randomized control subjects who wore conventional rigid contact lenses. The duration of changes was studied by monitoring subjects after lens wear was discontinued. After an average of 444 days of contact lens wear the treatment group showed an overall mean reduction in spherical equivalent refractive error of 1.01 D compared with 0.54 D in the control group (p = 0.02). Both groups had considerable variation in refractive error change. Corresponding mean improvements in unaided visual acuity were -0.27 and -0.20 log of the minimum angle of resolution [log (MAR)]. Corneal curvature decreased in both comparison groups, but the actual diopter value was about one-half that of the refractive change. The changes in these characteristics tended to occur during the first 132 days of wear, and additional aggressive lens therapy during the remaining 241 days of treatment produced little additional change. The refractive error fluctuated considerably during the period of follow-up and these fluctuations tended to be larger in those subjects who had shown greater changes in refractive error. When the lenses were removed, ocular characteristics returned steadily toward baseline levels. Ninety-five days after discontinuing lens wear, the refractive error had returned 75 and 69% of the way to baseline levels for the treatment and control groups, respectively. Visual acuity and corneal curvature showed similar rebound after 95 days. We conclude that it is possible to reduce myopia about 1D; however, the change is not permanent. Results indicate that the level of vision during periods of nonlens wear would be unstable, making it difficult to predict what the quality of vision would be under a retainer lens wear program.

Clinical Trials as Topic↗
PubMed1983

The Berkeley Orthokeratology Study, part III: safety.

The safety of orthokeratological (OK) procedures was assessed by monitoring several ocular characteristics including corneal thickness, refractive astigmatism, corneal astigmatism, correctable spectacle-acuity, corneal edema, corneal staining, and endothelial cell density. Safety was also assessed by reviewing the number and causes of extra clinical visits that occurred because of ocular complications and by determining whether safety factors were related to patients lost to follow-up. Over the 1.2-year period from the baseline examination to the end of the lens-wearing phase of the study, the Treatment (T) and Control (C) groups had, respectively, only small changes in their mean levels of corneal thickness (0.2 vs. 3.2 microns), refractive astigmatism (0.07 vs 0.01 D), and corrected spectacle acuity (0.02 vs 0.018 logarithm of the minimum angle of resolution). Analysis of time trend data obtained from scheduled monthly examinations also showed that changes in mean corneal thickness and mean corneal astigmatism were small and not clinically important in either comparison group during the course of the treatment. As a result of complications from lens wear, the T group required 1.25 times as many extra visits as the C group (p = 0.14). However, none of these visits provided sufficient clinical indication for the discontinuance of lens wear. Loss to follow-up typically occurred because of either poor compliance with the study protocol or loss of motivation caused by minor contact lens-related symptoms such as blurred vision, slight discomfort, or frequently lost lenses. These reasons were similar in both comparison groups. It appears that OK treatment is safe for the types of patients who participated in this study, but it may require more patient monitoring than would be needed to achieve and maintain a physiologically acceptable fit with conventional hard contact lens prescriptions.

Astigmatism↗
PubMed1982

Reconstruction of the periocular mucous membrane by autologous conjunctival transplantation.

We have extended the concept of autologous conjunctival transplantation for corneal resurfacing as recommended by Thoft to reconstruction in 14 patients with unilateral abnormalities of the bulbar and palpebral conjunctiva caused by alkali burns (2), irradiation (2), neoplasms (3), degenerative diseases (5), trauma (1), and developmental anomalies (1). Large, free conjunctival grafts from bulbar and forniceal donor sites were used. No complications have been noted at the recipient or donor sites. Grafts of normal conjunctiva provided intact basement membrane, goblet cells, and epithelium that help restore normal ocular and lid surfaces. The use of free conjunctival grafts provides significant advantage over the use of buccal mucous membrane grafts. The techniques and results of our experience with free conjunctival grafts in 14 patients are discussed.

Adolescent↗
PubMed1979

Visual prognosis in bacterial endophthalmitis treated with intravitreal antibiotics.

Eleven of 16 cases of human culture-proved endophthalmitis have been successfully treated with the intravitreal administration of 400 micrograms of gentamicin sulfate and 360 micrograms of dexamethasone with concomitant use of systemic antibiotics and prednisone. Seven of the 16 eyes (44%) had final visual acuity of 20/400 or better. Four additional eyes had residual useful vision after treatment. The visual prognosis in these cases is directly related to the exotoxin and proteolytic enzyme activity of the organisms. Delay of more than 36 hours between onset of symptoms and intravitreal treatment adversely affects the visual outcome. If a highly virulent organism has been isolated or if treatment has been delayed, vitrectomy to treat acute endophthalmitis is indicated. The comparatively high rate of recovery in this series is probably related to the high dose of intravitreal gentamicin utilized and the concomitant intraocular use of dexamethasone.

Anti-Bacterial Agents↗
PubMed1978

Experimental aspects and their clinical application.

After laboratory evaluation of nontoxic doses of intravitreal antibiotics, 26 cases of bacterial and fungal endophthalmitis were treated by intravitreal antibiotic or vitrectomy. In 46% of all cases, visual acuity was better than 20/100, whereas 27% had light perception to 20/300 visual acuity, 4% had no light perception, and 23% of the cases were enucleated or eviscerated. Best results have been achieved when the treatment began within 36 hours after symptomatic onset of infection and when the organism involved was not to virulent. We advocate intravitreal antibiotics immediately after intracameral and vitreous tap for culture, to be followed by vitrectomy 24 hours later if the culture is positive. In bacterial endophthalamitis when the vitreous is severely involved and in cases of fungal endophthalmitis, we advocate vitrectomy plus intravitreal antibiotics as the primary procedure.

Animals↗
PubMed1977

Cytologic diagnosis of adenoviral epidemic keratoconjunctivitis by direct immunofluorescence.

A direct immunofluorescence technique for the diagnosis of acute adenoviral keratoconjunctivitis and pharyngoconjunctivitis was found to be a reliable, sensitive, and specific technique for the detection of soluble adenoviral antigens in epithelial cells on conjunctival scrapings of patients with epidemic keratoconjunctivitis. Of 25 patients with clinical findings consistent with epidemic keratoconjunctivitis or pharyngoconjunctival fever, all had positive diagnostic scrapings by direct immunofluorescence.

Adenoviridae Infections↗
PubMed1976

Anterior segment ischemia and sector iris atrophy: after strabismus surgery in a patient with chronic lymphocytic leukemia.

A 69-year-old woman with chronic lymphocytic leukemia developed segmental iris atrophy and iridocyclitis after routine surgery for exotropia. Both the clinical picture and fluorescein angiogram indicated anterior segment ischemia. It is postulated that this was related to hyperviscosity of the blood caused by a high white blood cell count (114,000/cu mm). The possibility of anterior segment ischemia should be kept in mind when contemplating strabismus or retinal detachment surgery in the presence of hematologic disorders likely to increase blood viscosity. In these cases a minimal amount of surgery should be done with proper supportive therapy. Strabismus surgery should be done in stages allowing for hemodynamic compensation between procedures.

Aged↗
PubMed1976

Immunofluorescent detection of adenovirus antigen in epidemic keratoconjunctivitis.

An immunofluorescent technique was used to demonstrate soluble adenoviral antigens in epithelial cells on conjunctival scrapings of patients with epidemic keratoconjunctivitis (EKC). Conjunctival scrapings for immunofluorescence and viral isolation studies were performed on 79 patients suspected of having EKC or other acute follicular or papillary conjunctivitides. Of 41 patients with clinical findings consistent with a diagnosis of EKC and three patients with pharyngoconjunctional fever, 43 were positive by immunofluorescence. All 39 patients with adenovirus isolation had positive immunofluorescence studies. The five remaining cases had other documented evidence of EKC. No false-positive responses were encountered in relation to the clinical diagnoses. The fluorescent staining was predominantly found in the cytoplasm. Speckled nuclear fluorescence was also noted. The cytoplasmic fluorescence is compatible with the adenovirus cellular replication cycle. The immunofluorescent technique was found to be a reliable, sensitive, specific, and rapid diagnostic technique for detection of group-reaction adenoviral antigens in conjunctival scrapings.

Adenoviridae↗
PubMed1975

The experimental and clinical use of intravitreal antibiotics to treat bacterial and fungal endophthalmitis.

The experimental data involving the use of 14 antibacterial and two antifungal agents have been used to establish a rationale for the management of human endophthalmitis. Twelve cases of endophthalmitis treated under our supervision have been described in detail. The eventual visual outcome is related to two factors: (1) time interval between diagnosis and institution of adequate therapy, and (2) the severity of the organism and its ability to produce exotoxins and proteolytic enzymes. Eleven of 12 cases were cured with the recommended dosages of gentamicin and dexamethasone (400 mcg and 360 mcg, respectively). Eight of the 12 patients retained useful vision of 20/200 or better.

Aged↗
PubMed1975

Vitrectomy in exogenous Candida endophthalmitis.

A case of Candida endophthalmitis was clinically diagnosed three weeks after perforating injury. It was successfully treated with vitrectomy and intravitreal injection of 5 mcg of amphotericin B. A Candida speices was cultured from the vitreous aspirations.

Amphotericin B↗