Biomedical subjects

Sandra Stinnett

Publications and source records attributed to Sandra Stinnett.

14 recordsLinked to original sources

PubMed2006

Efficacy of low-release-rate fluocinolone acetonide intravitreal implants to treat experimental uveitis.

OBJECTIVE: To determine the efficacy of 0.5-mg and 0.1-mg sustained-release fluocinolone acetonide intravitreal implants to inhibit ocular inflammation in a rabbit model of severe uveitis. METHODS: The in vitro pharmacokinetic profile of both the 0.5-mg and 0.1-mg sustained-release fluocinolone intravitreal implants was determined during a 10-day period. A sustained-release fluocinolone acetonide intravitreal implant with a release rate of either 0.5 microg/d (n = 16) or 0.1 microg/d (n = 16) was implanted into the vitreous cavity of the right eye in albino rabbits after a subcutaneous injection of tuberculin antigen. Control animals (n = 14) received empty devices. Uveitis was induced with an intravitreal tuberculin antigen injection. A masked observer graded anterior chamber flare, anterior chamber cells, vitreous opacity, and inflammation on histologic sections. RESULTS: In vitro, the drug was released from both devices in a linear manner. In vivo, treated eyes were significantly less inflamed than untreated eyes (P< or =.02). Inflammation was suppressed to a greater degree with the 0.5-microg/d implant compared with the 0.1-microg/d implant. CONCLUSION: Sustained-release fluocinolone intravitreal implants suppress ocular inflammation in a rabbit model of severe uveitis. CLINICAL RELEVANCE: The efficacy demonstrated with the 0.1-microg/d implant provides the rationale for future human studies with lower-release-rate implants than are currently used in noninfectious uveitis clinical trials.

Animals↗

PubMed2006

Central retinal vein occlusion in patients treated with long-term warfarin sodium (Coumadin) for anticoagulation.

PURPOSE: To describe the clinical features of persons who developed central retinal vein occlusion (CVO) while being treated with Coumadin for chronic anticoagulation. METHODS: In a retrospective, comparative, noninterventional case series of patients diagnosed with CVO while being treated with Coumadin as a systemic anticoagulant, visual and anatomical outcomes were compared with those for a cohort of patients diagnosed with CVO who were not treated with any systemic anticoagulation. RESULTS: Fourteen eyes of 14 patients treated with Coumadin were identified. At presentation, the median international normalization ratio (INR) was 2.20 (range, 1.3-5.0). Eight patients (57%) had a therapeutic INR at the time of CVO. Their visual acuity and perfusion status were similar to those of patients with subtherapeutic INR. At the last follow-up (median, 16 months), visual acuity and perfusion status of the group of 14 eyes were similar to baseline findings (P = 0.62). Clinical features and outcomes were similar to those for a cohort of patients with CVO who were not being treated with systemic anticoagulation. CONCLUSION: CVO can occur in patients being treated with Coumadin for systemic anticoagulation. Final visual acuity and perfusion status were similar to those in a cohort of patients with CVO who were not treated with Coumadin. Although visual acuity is unaffected, ensuring that the INR for these patients remains in the therapeutic range may be important to help prevent secondary systemic thrombotic and embolic disease.

Aged↗

PubMed2006

Quality of life of patients with otitis media and caregivers: a multicenter study.

OBJECTIVE: The objective of this study was to determine the quality of life of otitis media (OM) patients and their caregivers. STUDY DESIGN: A cross-sectional study was conducted at 11 otolaryngology and five pediatric clinics in the United States between July 1998 and August 1999. All patients, regardless of primary complaint, completed a demographic survey, OM-6 survey, and Child Health Questionaire-PF28 survey by proxy. Physicians completed an International Classification of Diseases, 9th Revision diagnosis sheet for each patient. METHODS: Analysis, including Spearman rank correlation, was restricted to study patients with active OM. RESULTS: A total of 1,001 patients with active OM were identified: 503 OM with effusion, 267 acute OM, and 258 recurrent acute OM. Median patient age was 2 years (interquartile range, 1-5). Mean caretaker age was 32.6 years (standard deviation, 7.4). There was moderate correlation between OM frequency and physical suffering (r = 0.50; P < .001) and caregiver concerns (r = 0.45; P < .001). Moderate correlation was found between percentage of time with fluid in the ears and caregiver concerns (r = 0.46; P < .001) and physical suffering (r = 0.43; P < .001). OM patients over 5 years of age scored significantly worse than healthy children ages 5 to 7 years in almost all areas of global health, including physical functioning and impact on caretaker's personal time and emotions. CONCLUSION: The global quality of life of patients with OM over 5 years of age is worse than that of healthy children of similar age. Physical suffering and caregiver concerns are associated with frequent OM or effusion duration. Hopefully, these results will direct the focus of future outcomes studies.

Acute Disease↗

PubMed2006

Retrospective review of eyes with neovascular age-related macular degeneration treated with photodynamic therapy with verteporfin and intravitreal triamcinolone.

AIM: To review the outcomes of eyes with neovascular age-related macular degeneration (AMD) treated with photodynamic therapy (PDT) with verteporfin and intravitreal triamcinolone acetonide injection. MATERIALS AND METHODS: We retrospectively reviewed the outcomes of consecutive eyes with neovascular AMD that received an intravitreal triamcinolone injection within 1 week of their first PDT and had at least 6 months of follow-up. Eyes were retreated with PDT at 3-month intervals if angiographic leakage was present. RESULTS: Twenty-six eyes from 24 patients were identified. The mean visual acuity at baseline was 20/118 (median 20/112). The mean visual acuity decreased to 20/138 at 9 months (P = 0.24, n = 15) and to 20/174 at 12 months (P = 0.23, n = 8). The change in visual acuity from baseline was not statistically significant at any time point. The mean central foveal thickness by OCT measured 342 microm at baseline and decreased to 296 microm at 12 months (P = 0.31). Sixty-two per cent of eyes required no additional PDT at 12 months. Nineteen per cent of 26 eyes had a rise in intraocular pressure that was controlled with topical medication alone. CONCLUSION: Photodynamic therapy with verteporfin combined with intravitreal triamcinolone injection in the treatment of neovascular AMD may be superior to PDT alone by decreasing visual loss and reducing the number or retreatments.

Age Factors↗

PubMed2005

Risk factors for progression to penetrating keratoplasty in patients with keratoconus.

PURPOSE: To determine clinical and demographic risk factors for corneal transplantation in keratoconus patients. DESIGN: Case control study. METHODS SETTING: Tertiary referral center. STUDY POPULATION: All keratoconic eyes presenting to the Duke University Eye Center from January 1, 1997, to December 31, 2002. OBSERVATION PROCEDURE AND OUTCOME MEASURES: Cases were defined as eyes undergoing transplantation during the study period for keratoconus. Controls were defined as eyes that did not undergo transplantation. Cases were compared with controls to determine clinical and demographic risk factors for corneal transplantation. RESULTS: A total of 131 eyes with keratoconus were studied; 59 cases were compared with 72 controls. Groups were similar with respect to sex and race. Significant univariate risk factors for corneal transplantation were best-corrected vision worse than 20/40 (OR 3.2, 95% CI 1.1 to 9.8), cylinder >10.0 diopters (OR 3.5, 95% CI 1.0 to 12.4), and average keratometry >55 diopters (OR 5.6, 95% CI 1.4 to 21.9). In multivariate analysis, age 30 or younger conferred a sevenfold increased risk of transplantation compared with ages of more than 40 (OR 7.7 for ages 21 to 30 and OR 25.8 for ages < or = 20). Multivariate analysis also showed duration of disease 5 years or less and steep average keratometry as significant risk factors. CONCLUSIONS: A subset of young keratoconic patients with high keratometry values may represent an underrecognized risk group for corneal transplantation. Best-corrected visual acuity worse than 20/40 at presentation and astigmatism are other clinical indicators of increased risk of corneal transplantation in keratoconus patients.

Adult↗

PubMed2005

Trends in the indications for penetrating keratoplasty, 1980-2001.

PURPOSE: To study the leading indications and changing trends for penetrating keratoplasty (PK) over the past 3 decades. METHODS: This is a retrospective review of 696 cases of PK. The indications for PKs performed at the Duke University Eye Center during the years 1980-1981, 1990- 1991, and 2000-2001 were tabulated to determine trends over the past 3 decades. The main outcome measures were indications for PK. RESULTS: During this study, 696 PKs were performed. The leading indications for PK and their respective frequencies during 1980-1981, 1990-1991, and 2000-2001 were failed grafts (10.8%, 19.0%, 27.0%, respectively), pseudophakic bullous keratopathy (PBK)/aphakic bullous keratopathy (ABK) (19.4%, 20.6%, 16.7%, respectively), Fuchs dystrophy (15.6%, 13.0%, 23.8%, respectively), keratoconus (13.4%, 8.2%, 11.8%, respectively), and corneal scar (7.0%, 8.9%, 10.7%, respectively). The number of PKs for failed grafts and Fuchs dystrophy increased over time. CONCLUSIONS: In this study, failed graft has gradually become the leading indication for PK, whereas most other studies have reported PBK as the leading indication. Unlike many other studies, Fuchs dystrophy was a common indication for PK.

Corneal Diseases↗

PubMed2004

New dendritic adhesives for sutureless ophthalmic surgical procedures: in vitro studies of corneal laceration repair.

OBJECTIVE: To compare a biodendrimer adhesive with a conventional suture for repairing linear and stellate corneal lacerations. METHODS: A keratome knife was used to create 4.1-mm full-thickness linear incisions (n = 36) and 3 x 4-mm full-thickness stellate incisions (n = 25) in the central cornea of enucleated human eyes. The incisions were sealed with either a suture or the biodendrimer adhesive. The globes were inflated with balanced salt solution, and the increase in intraocular pressure was monitored via a cardiac transducer until fluid leaked from each eye. This intraocular pressure reading from the transducer was recorded at the sight of any leakage through the wound (leakage pressure). By using the Wilcoxon rank sum test, the median leakage pressure was compared for each closure method, separately for each wound group. By using the 1-sided 1-sample t test, each mean leakage pressure value was compared with 34 mm Hg, which is the intraocular pressure under certain stressful physiologic conditions (eg, coughing and the Valsalva maneuver). RESULTS: For globes that underwent a linear incision, the mean leakage pressure was 78.7 mm Hg for the sutured group and 109.6 mm Hg for the adhesive group. Globes that underwent a stellate incision had a mean leakage pressure of 57.8 mm Hg for the sutured group and 78.7 mm Hg for the adhesive group. All of these pressures showed a statistical significance from 34 mm Hg via a 1-sided 1-sample t test. CONCLUSIONS: The difference in leakage pressures for all 4 groups was statistically significant relative to 34 mm Hg. This suggests that either method of closure, adhesive or suture, can withstand physiologic increases in intraocular pressure postoperatively and that biodendrimer adhesives are able to seal large corneal lacerations.Clinical Relevance The use of biodendrimer adhesives to repair a corneal wound constitutes a viable alternative clinical procedure to conventional sutures.

Biocompatible Materials↗

PubMed2004

Clinical comparison of the Proview eye pressure monitor with the Goldmann applanation tonometer and the Tonopen.

OBJECTIVE: To compare intraocular pressure (IOP) values obtained by patients using the new Proview eye pressure monitor (Bausch & Lomb, Rochester, NY) with those measured with the Goldmann tonometer and the TonoPen (Mentor, Norwell, Mass). METHODS: Eighty-six patients (a total of 171 eyes) with a diagnosis of glaucoma or glaucoma suspect successfully completed the study. The IOP was measured by 3 methods in the following order: Goldmann tonometer, TonoPen, and Proview eye pressure monitor. The central corneal thickness was measured by an ultrasonic pachymeter. Separately for each eye, the differences in mean IOP values between measurement methods were assessed with paired t tests and also in multivariate models that tested the dependence of IOP difference on central corneal thickness. RESULTS: There was a significant difference (P<.001) in the mean IOPs measured by the 3 different methods (Goldmann vs Proview, Goldmann vs TonoPen, and TonoPen vs Proview) for both eyes, and the difference was independent of the central corneal thickness. The differences between IOP measured by Goldmann and Proview were similar in all categories of patient-reported ease of using the Proview. CONCLUSIONS: The IOPs obtained with the Proview eye pressure monitor are significantly lower than those measured with Goldmann tonometer and the TonoPen, and variations of the central corneal thickness do not contribute to the difference. Intraclass correlations of IOP values obtained with the Goldmann and the Proview or TonoPen and Proview are not strong. On the other hand, as expected, measurements with Goldmann and TonoPen agreed fairly well.

Adult↗

PubMed2004

Prevalence and risk factors for proliferative vitreoretinopathy in eyes with rhegmatogenous retinal detachment but no previous vitreoretinal surgery.

PURPOSE: To determine the prevalence of and risk factors for proliferatative vitreoretinopathy (PVR) in eyes with rhegmatogenous retinal detachment but no previous vitreoretinal surgery. DESIGN: Observational case series. METHODS: Prospective study. SETTING: A private vitreoretinal clinic in Caracas, Venezuela. STUDY POPULATION: 119 eyes of 119 patients who presented with rhegmatogenous retinal detachment but no previous vitreoretinal surgery between 1995 and 1998. OBSERVATION PROCEDURES: Data from detailed preoperative and postoperative examinations of each eye were recorded prospectively and entered into an electronic database. MAIN OUTCOME MEASURES: Prevalence of PVR of any type and severe PVR, preoperative risk factors for PVR of any type and severe PVR, effect of PVR and retinal detachment duration on initial and final visual acuity, and surgical complexity. RESULTS: The prevalence of PVR of any type was 52.9% and of severe PVR was 26.9%. The mean retinal detachment duration (+/-SD) was 58.4 (+/-129.1) days, and the mean time from initial examination to surgical treatment (+/-SD) was 24.3 (81.2) days. By univariable analysis, long retinal detachment duration, poor initial visual acuity, and large retinal detachment extent were significantly associated with PVR prevalence and severity. The presence of vitreous hemorrhage was significantly associated with PVR prevalence, and cataract was significantly associated with PVR severity. By multivariable analysis, long retinal detachment duration and large retinal detachment extent were simultaneous risk factors for PVR prevalence, while long retinal detachment, large retinal detachment extent, and poor initial visual acuity were simultaneous risk factors for PVR severity. Eyes with longer retinal detachment duration, PVR of any type, and severe PVR had worse initial and final visual acuities than eyes with shorter retinal detachment duration or those without PVR, respectively. Eyes with PVR had more complex surgery than those without PVR. CONCLUSIONS: PVR occurred very frequently in this population and was associated with more complex surgery and worse visual outcomes than among eyes without PVR. We have identified preventable risk factors associated with PVR that suggest a specific and significant need for better access to ophthalmologic care and patient education in this group of patients.

Adolescent↗

PubMed2004

Demographic-related variations in posterior segment ocular sarcoidosis.

OBJECTIVE: To compare the frequency of posterior segment involvement (PSI), the prevalence of specific posterior segment signs, and visual acuity in ocular sarcoidosis by patient race, sex, and age. DESIGN: Retrospective, cross-sectional observational study. PARTICIPANTS: Seventy-six consecutive patients with biopsy-proven or presumed ocular sarcoidosis seen at the Duke University Eye Center between 1989 and 2001. METHODS: Medical record review. MAIN OUTCOME MEASURES: Patient demographics, presence and laterality of specific posterior segment signs, and visual acuity at initial examination. RESULTS: Of the 76 patients, 68% were black (34 female and 18 male) and 32% were white (18 female and 6 male). A total of 68 patients (89%) had PSI: black patients had 85% and white patients had 100% (P = 0.05). For patients with PSI, white females had the highest mean age at initial examination (58 years compared with 37 years for all others; P = 0.005). The most common findings among the 68 patients with posterior segment disease were vitritis (69%); choroidal "punched-out" lesions (56%); "snowball" lesions (46%); cystoid macular edema (CME; 31%); and periphlebitis, vitreous opacity, and posterior vitreous detachment (29% each). There was a significantly higher prevalence of "punched-out" lesions and CME in whites (79% and 54%, respectively) compared with blacks (43% and 18%, respectively; P = 0.005 each). Additionally, the prevalence of CME was highest in white females (61%) compared with all others (20%; P = 0.002). Patients with vitreous hemorrhage were more likely to be in the youngest age group (P = 0.02). Female patients with posterior segment disease had a significantly lower visual acuity compared with males in both the better (P<0.001) and worse (P = 0.002) eye. CONCLUSIONS: We have identified variations based on patient race, sex, and age in PSI, specific posterior segment signs, and visual acuity in cases of ocular sarcoidosis.

Adolescent↗

PubMed2004

Effects of indocyanine green on the retina and retinal pigment epithelium in a porcine model of retinal hole.

PURPOSE: This study was designed to emulate human macular hole surgery and to test the effects of indocyanine green (ICG) on the retina and retinal pigment epithelium (RPE). METHODS: Yorkshire Cross pigs (n = 23) underwent vitrectomy, separation of the posterior cortical vitreous, and creation of a single retinal hole. In three study groups (n = 6, each group), air-fluid exchange was performed, following which balanced salt solution (BSS), 1.0% ICG, or 0.5% ICG was applied over the retinal hole. In one additional group (n = 5), 0.5% ICG was injected into the fluid-filled eye. At 4 weeks, the eyes were examined clinically, and fundus photographs were obtained before enucleation and light microscopic examination. RESULTS: Clinical evaluations documented a statistically significant difference between study groups (P = 0.036). There was a higher rate of moderate or severe RPE atrophy among animals where 1% or 0.5% ICG was applied in air-filled eyes (83% and 67%, respectively) compared with BSS controls (17%) and fluid-filled eyes receiving 0.5% ICG (40%). Histologic evaluation demonstrated a statistically significant difference between groups (P = 0.044), with extensive outer retinal degeneration observed in air-filled eyes receiving 1% or 0.5% ICG (66% and 60%, respectively) compared with BSS controls or fluid-filled eyes receiving 0.5% ICG (none of the eyes in either group). None of the study groups had any changes in the inner retina except at the retinal hole site. CONCLUSIONS: Retina exposed to ICG concentrations used in human vitreoretinal surgery had greater RPE atrophy and outer retinal degeneration than control eyes undergoing the same surgery without ICG. Eyes filled with infusion fluid during ICG injection had less damage to the RPE and outer retina than did air-filled eyes receiving ICG.

Air↗

PubMed2003

Lensectomy and vitrectomy decrease the rate of photoreceptor loss in rhodopsin P347L transgenic pigs.

BACKGROUND: Photoreceptor degeneration in retinitis pigmentosa (RP) runs an inevitable, gradually progressive course. A wide variety of growth factors of different origins have been shown to slow the rate of degeneration in some rodent models of RP. Recently, lens-derived neurotrophic factors have been shown to rescue degenerating ganglion cells in crush models of the optic nerve. Our objective was to evaluate the potential rescue effect of lensectomy and vitrectomy (L&V) on photoreceptor degeneration in a large-animal model, the rhodopsin P347L transgenic pig. METHODS: We operated on one eye of each of 49 3-week-old pigs--15 vitrectomies and 34 L&V, 6 of which received steroids. Retinal paraffin sections were prepared for all eyes, in addition to immunohistochemistry in four eyes, 8 weeks after L&V. RESULTS: At eight weeks after L&V, operated eyes showed significantly more nuclei in the outer nuclear layer (ONL) than the unoperated fellow eyes. The better preservation of the ONL persisted but was less prominent by 20 weeks after surgery. Steroid treatment did not markedly reduce the better preservation of the ONL seen at 8, 10, and 12 weeks after surgery. The significant difference in cell count between operated and unoperated eyes in the L&V group at 8 weeks was due to the difference in the number of rods, not the cones. CONCLUSION: Lensectomy and vitrectomy delay photoreceptor degeneration in rhodopsin P347L transgenic pigs. Lens-related rescue effect is a probable reason for the delayed degeneration.

Animals↗

PubMed2003

Correlation among retinal thickness, optic disc, and visual field in glaucoma patients and suspects: a pilot study.

OBJECTIVE: To correlate losses of retinal thickness in the perifoveal area in glaucoma as measured by the Retinal Thickness Analyzer (Talia Technology Ltd, Israel) with optic nerve and visual field changes in glaucoma patients and suspects. METHODS: Observational case series of 55 consecutive patients from the Glaucoma Service who either presented with a diagnosis of glaucoma or were referred for evaluation of suspected glaucoma. The Retinal Thickness Analyzer (Talia Technology, Ltd.) was used to obtain retinal thickness maps. Retinal thickness analysis, visual field testing, and stereophotography of the optic nerve head were performed, and a glaucoma specialist who was masked to patient status and identity data randomly graded the level of severity of each parameter. Spearman rank correlations were used to assess the relationships among the three numerical measures. RESULTS: Retinal thickness losses correlated more strongly with severity of optic nerve head cupping (r = 0.75), whereas both of these measures correlated less strongly with the severity of visual field loss (r = 0.54). CONCLUSIONS: Retinal thickness measurements at the posterior pole provide another measure of neural loss in glaucoma, and may help in the clinical assessment of optic nerve cupping. However, there are limitations of the technology that must be considered.

Adult↗

PubMedDate not supplied

Cellular senescence in the glaucomatous outflow pathway.

The mechanisms responsible for the progressive malfunction of the trabecular meshwork (TM)-Schlemm's canal (SC) conventional outflow pathway tissue in primary open angle glaucoma (POAG) are still not fully understood. To determine whether POAG is characterized by an accumulation of senescent cells, similar to what has been described in other diseases, we have compared the levels of the senescence marker senescence-associated-beta-galactosidase (SA-beta-gal) in the outflow pathway cells of POAG and age-matched control donors. POAG donors demonstrated a statistically significant fourfold increase in the percentage of SA-beta-gal positive cells. These results suggest a potential role for cellular senescence in the pathophysiology of the outflow pathway.

Aged↗