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Biomedical subjects

C P Wilkinson

Publications and source records attributed to C P Wilkinson.

At least 19 recordsLinked to original sources
PubMed1992

Diabetic retinopathy in Oklahoma Indians with NIDDM. Incidence and risk factors.

OBJECTIVE: To determine the incidence rates and risk factors for development of diabetic retinopathy in Oklahoma Indians. RESEARCH DESIGN AND METHODS: Cohort follow-up study with baseline examination between 1972 and 1980 and follow-up examination between 1987 and 1991. Mean +/- SD follow-up time was 12.8 +/- 1.7 yr. Eleven Indian Health Service facilities (clinics and hospitals) in Oklahoma participated in the study. Study participants were a quasirandom sample of 1012 American Indians (379 men, 633 women) in Oklahoma with NIDDM, 927 of whom received a detailed eye examination at baseline. The mean age of participants was 52 yr with a duration of diabetes of 6.9 yr at baseline. The average quantum of Indian blood was 92% (77% full blood). At follow-up, 515 (55.6%) were alive, 408 (44.0%) were deceased, and 4 (0.4%) could not be traced. Of the living participants, 380 (73.8%) underwent an ophthalmoscopic examination. RESULTS: The incidence of retinopathy among the participants who were free of disease at baseline and who survived the follow-up interval was 72.3%. By multivariate analysis, significant independent predictors of retinopathy recorded at baseline were FPG level, therapeutic regimen, systolic blood pressure, and duration of diabetes. FPG levels > or = 11.1 mM (200 mg/dl) increased the risk of retinopathy 1.7 times that for levels < 7.8 mM (140 mg/dl). Insulin use was associated with a 20% greater incidence. Hypertension was a particularly significant risk factor for those with lower FPG levels. CONCLUSIONS: Given that NIDDM is reaching epidemic proportions in Oklahoma Indians and that most may be afflicted with retinopathy, frequent ophthalmological examinations are clearly indicated for this high-risk population. The role of intervention, namely glycemic and hypertensive control, deserves further study.

Blood Glucose↗
PubMed1991

Corneal ulcer and adverse reaction rates in premarket contact lens studies.

We analyzed clinical data on 22,739 contact lens wearers who were studied and whose lenses were approved under 48 manufacturer-sponsored studies for the Food and Drug Administration between 1980 and 1988. The incidence of corneal ulcers was low in the cosmetic (nontherapeutic) daily-wear soft and rigid gas-permeable lens wearers (1/1,923 and 1/1,471 patient-years, respectively). Corneal ulcers and severe adverse reactions occurred two to four times more frequently in extended-wear cosmetic soft and rigid gas-permeable lens wearers than in cosmetic daily-wear lens wearers. Aphakic extended-wear soft lens users were nine times more likely to develop a corneal ulcer when compared to the soft daily-wear cosmetic group. Corneal abrasions and keratitis accounted for 81 of 159 severe adverse reactions, whereas corneal ulcers accounted for 28 of 159 adverse reactions. The data indicate that overnight extended wear of contact lenses is associated with a greater risk of serious, sight-threatening complications than daily wear.

Aphakia↗
PubMed1991

Cilioretinal artery occlusion in young adults with central retinal vein occlusion.

Ten patients, all younger than 50 years of age, had a temporal cilioretinal artery occlusion associated with a nonischemic central retinal vein occlusion. On fluorescein angiography, the cilioretinal artery eventually filled in all but one eye. The cilioretinal artery showed pulsations on fluorescein angiography in five eyes. The central retinal vein occlusion eventually resolved and the fundus assumed a normal appearance in all nine of the followed cases. Eight of nine eyes that underwent follow-up examination had final visual acuity of 20/30 or better. The occlusion of the central retinal vein produces an elevation of intraluminal capillary pressure because the central retinal artery continues to pump blood into the retina. Because the perfusion pressure of the cilioretinal artery is lower than the central retinal artery, it becomes relatively occluded. The prognosis for these patients is generally good unless the entire parafoveal capillary net is affected by the cilioretinal artery that is occluded.

Adult↗
PubMed1991

Enlargement of circumscribed choroidal hemangiomas.

The authors describe five patients with circumscribed choroidal hemangiomas. Fundus photography, fluorescein angiography, and ultrasound examinations showed progressive enlargement of these hemangiomas. In all cases, the extent of lesion enlargement was slight: the mean change in tumor size was 1.6 mm x 1.5 mm in basal diameters by 0.9 mm in thickness during a median interval of 52 months (range 33 to 100 months) between initial tumor diagnosis and detection of lesion enlargement. This series of cases demonstrates that circumscribed choroidal hemangiomas can enlarge slightly during long intervals between observations.

Adolescent↗
PubMed1990

Bilateral diffuse uveal melanocytic proliferation in patients with occult carcinoma.

The development of multiple, round or oval, subtle, red patches at the level of the pigment epithelium in the posterior ocular fundus and their striking early hyperfluorescence angiographically are characteristic features of the bilateral diffuse uveal melanocytic proliferation syndrome. They may be accompanied by severe visual loss and may antedate the appearance of multiple melanocytic tumors, retinal detachment, and cataract in these patients with occult systemic carcinomas. These hyperfluorescent patches are caused by focal damage to the pigment epithelium overlying an intact choriocapillaris and diffuse benign nonpigmented uveal melanocytic infiltration of the outer choroid. We suggest that outer retinal damage may not be primarily caused by melanocytic proliferation, but rather by toxic and immune factors generated by interaction between a systemic carcinoma and congenital melanocytosis of the uveal tract. We report the longest survivor of this disorder to date (102 months).

Aged↗
PubMed1990

Goldmann-Favre maculopathy.

A healthy 17-year-old girl presented with typical symptoms and physical features of Goldmann-Favre vitreoretinal degeneration. She had reduced visual acuity in both eyes and night blindness. Her parents were first cousins. Striking fundus features included typical maculopathy with a radiating stellate pattern surrounded by tiny vacuole-like pockets of retinoschisis throughout the posterior pole within the temporal vascular arcades. The fundus features were quite typical and permitted a firm diagnosis when combined with the other features of night blindness, gender, and electroretinogram (ERG) abnormalities.

Adolescent↗
PubMed1989

Visual acuity after the repair of pseudophakic retinal detachments involving the macula.

Postoperative visual acuities were retrospectively evaluated in a series of 100 pseudophakic eyes in which rhegmatogenous retinal detachments involved the macula and in which reattachment surgery was anatomically successful. Preoperative visual acuity and duration of macular detachment were related to visual outcome. Eyes in which extracapsular surgery had been followed by posterior chamber lens implantation had significantly better postoperative visual acuities than cases in which older iris-fixation intraocular lenses (IOLS) were placed after intracapsular procedures. Retinal detachments associated with posterior chamber IOLs have a relatively favorable anatomical and visual prognosis.

Adult↗
PubMed1989

Pseudophakic retinal detachments. The relationships between retinal tears and the time following cataract surgery at which they occur.

The types and locations of retinal tears associated with 268 pseudophakic retinal detachments were studied as a function of the time at which they occurred following cataract surgery. Retinal detachments occurring more than two years following cataract extraction were significantly more likely to have their most posterior retinal break located at the posterior margin of the vitreous base than at or behind the equator. This distribution of tears was not observed in detachments occurring within six months of cataract surgery, with equatorial tears being significantly more common in early onset detachments than in those occurring after two years. The anterior tears which cause most retinal detachments long after cataract extraction are due to persistent chronic traction upon the vitreous base rather than to acute posterior vitreous detachment.

Aged↗
PubMed1988

Clinicopathologic correlation of pigmented epiretinal membranes.

We performed clinicopathologic correlation on ten surgically removed pigmented epiretinal membranes causing macular pucker. All cases occurred in eyes with existing retinal holes or tears, including eight cases of macular pucker after previous retinal detachment. These cases probably represented a limited form of proliferative vitreoretinopathy. All membranes contained pigment epithelial cells with polarity, basement membrane, and melanosomes. Cytoplasmic melanin granules accounted for the clinical feature of pigmentation in these eyes.

Astrocytes↗
PubMed1988

Angiographic cystoid macular edema after posterior chamber lens implantation.

We performed a prospective study evaluating the incidence of angiographic cystoid macular edema (CME) following extracapsular cataract extraction and posterior chamber intraocular lens implantation. Of the 162 eyes in the study, 141 were randomized into either a primary capsulotomy or a capsule intact group. The remaining eyes were not randomized due to intraoperative surgical complications, but they were included in the follow-up studies. Six weeks after surgery, angiographic CME was documented in 24% of the capsulotomy group and in 16% of the capsule intact group. The differences were not statistically significant. Including nonrandomized cases reduced the overall incidence of angiographic CME and the difference between the two groups. Angiographic CME was usually not extensive, and it was associated with a visual acuity less than 20/40 in 2.5% of eyes six weeks postoperatively. A subgroup of 120 eyes was followed up for approximately six months, when angiographic CME was present in 4% of the capsulotomy and capsule intact groups.

Aged↗
PubMed1988

Cystoid macular edema following extracapsular cataract extraction and posterior chamber intraocular lens implantation.

The outcome of clinical cystoid macular edema (CME) was studied in 20 symptomatic eyes in which extracapsular cataract extraction and posterior chamber intraocular lens implantation had been performed. Resolution of symptoms and apparent resolution of the macular edema were observed in 18 (90%) of the 20 cases. Clearing occurred within one year in 14 (78%) of these 18 eyes and in 17 (94%) within two years. In all eyes in which macular edema resolved, visual acuity returned to 20/40 or better. This study suggests that clinical cystoid macular edema occurring in association with a posterior chamber intraocular lens has a relatively favorable course.

Aged↗
PubMed1988

Recovery of visual acuity following the repair of pseudophakic retinal detachment.

Postoperative visual acuities were evaluated in a series of 100 pseudophakic eyes in which rhegmatogenous retinal detachments involved the macula and in which reattachment surgery was successful. Preoperative visual acuity and duration of macular detachment were directly and indirectly related to visual outcome, respectively. Eyes in which extracapsular surgery had been followed by posterior chamber lens implantation had significantly better postoperative visual acuities than cases in which older iris-fixation IOLs were placed following intracapsular procedures.

Adult↗
PubMed1987

Vitreous opacification after cataract extraction.

We performed pars plana vitrectomies on a consecutive series of 24 eyes in which nonhemorrhagic vitreous opacification was responsible for loss of visual acuity after cataract extraction. Twelve eyes were aphakic and the remainder were pseudophakic. Preoperative fluorescein angiograms were performed in 20 cases, and the results of all studies were within normal limits. Postoperatively, a restoration of clear media and an improvement in visual acuity occurred in all cases. Visual acuity was 20/20 or better postoperatively in 15 of 24 cases, and 22 of 24 achieved 20/30 or better. The remaining two cases improved to 20/40 and 20/50 from a preoperative level of 20/200 and 20/400, respectively. In carefully selected cases vitrectomy techniques provide an effective means of managing this syndrome.

Aged↗
PubMed1987

Rapid and sensitive method for measurement of hyaluronic acid and isomeric chondroitin sulfates using high-performance liquid chromatography.

A high-performance liquid chromatographic method for the separation and analysis of the unsaturated tetrasaccharide and hexasaccharide from Streptomyces hyaluronidase (S.HAase) enzyme digestion products of hyaluronic acid (HA) and standard unsaturated disaccharides 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (delta Di-0S), 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (delta Di-4S) and 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (delta Di-6S) is described. An amino phase chemically bonded to silica with a particle diameter of 6 micron was used as the column. The composition and the pH of the mobile phase were systematically varied to determine the optimal chromatographic conditions for separation and analysis of the compounds. For HA, a complete separation was accomplished in less than 12 min with a practical detection limit of 100 ng. Separation of the disaccharides also required less than 15 min with detection limits of 10 ng for delta Di-0S and 25 ng each for delta Di-4S and delta Di-6S. This chromatographic method represents a significant improvement over existing methods. It allows the simultaneous separation and analysis of HA and chondroitin sulfate isomers (after digestion of the latter with chondroitinase) at a higher speed, and with more sensitivity and efficiency.

Chondroitin↗
PubMed1986

Rhegmatogenous retinal detachment after neodymium-YAG laser capsulotomy in phakic and pseudophakic eyes.

A retrospective study of 18 eyes in 17 patients with rhegmatogenous retinal detachments after neodymium-YAG laser posterior capsulotomy was performed to determine operative settings and to describe anatomic changes after the procedure in an effort to assess their relationship to subsequent retinal detachment. The laser energy required to create a capsulotomy did not appear to be excessive and the capsulotomy openings were not unusually large. The time between YAG capsulotomy and diagnosis of retinal detachment ranged from four to 82 weeks (mean, 28 weeks). The characteristics of the retinal detachments were similar to those after routine cataract extraction. Retinal reattachment surgery was ultimately successful in all 18 eyes. Both YAG laser and knife-needle posterior capsulotomies may increase the risk of subsequent rhegmatogenous retinal detachment as a result of opening the capsule.

Adult↗
PubMed1986

Retinal detachment following intraocular lens implantation.

This report concerns a consecutive series of 154 pseudophakic eyes in which primary scleral buckling procedures were performed for rhegmatogenous retinal detachments. Most cases involved eyes in which extracapsular surgery had been combined with iridocapsular implants or posterior chamber lenses or in which iris-fixation intraocular lenses were placed following intracapsular surgery. The characteristics of the detachments were similar, although there was a trend towards an increased incidence of significant preoperative proliferative vitreoretinopathy in the intracapsular cases. Anatomical success rates were over 90% in all groups. There was a trend for lower visual acuities following successful surgery in the eyes in which intracapsular surgery had been performed than in those following extracapsular procedures.

Cataract Extraction↗
PubMed1986

The clinical examination. Limitation and over-utilization of angiographic services.

Fluorescein angiography has increased our understanding of the pathophysiology and appearance of most fundus disorders. Increased experience with the stereoscopic slit-lamp examination of the fundus has made it easier to predict what subsequent angiograms will demonstrate, and fluorescein studies are currently usually not required to make an appropriate diagnosis. Most cases of age-related macular degeneration and diabetic retinopathy can be managed without angiography, since most of the former are associated only with drusen and modest and progressive visual acuity loss and most cases of diabetic retinopathy are not associated with loss of visual acuity or with proliferative lesions. Angiography is an invaluable tool in evaluating newly symptomatic patients with the possibility of choroidal neovascularization, and it is also of great value in evaluating causes of visual acuity loss in diabetics as well as in the documentation of nonperfusion of their peripheral retinas.

Aging↗