PubMed Health⌕ Search

Biomedical subjects

Dennis P Han

Publications and source records attributed to Dennis P Han.

16 recordsLinked to original sources
PubMed2006

An eye model for practicing vitreoretinal membrane peeling.

A cost-effective, reusable practice eye model for epiretinal membrane peeling that uses easily obtained, commercially available materials was developed. A commercially available globe that is anatomically and optically similar to the human eye was modified by creating 2 ports that simulate superior sclerotomies. The model has a removable plastic anterior segment, which allows access to the posterior segment for practice membrane placement. Membranes were created on the macula by applying a coat of liquid skin bandage. Membrane peeling was performed under an ophthalmic operating microscope using a disposable flat vitrectomy lens. The basic skills required for membrane peeling can be demonstrated and acquired by practicing with this eye model. The practice eye model is expected to enhance the acquisition of skills required for epiretinal membrane peeling.

Epiretinal Membrane↗
PubMed2006

Recurrent bullous retinal detachments from photodynamic therapy for idiopathic polypoidal choroidal vasculopathy.

PURPOSE: To report the recurrent bullous retinal detachments as complications of photodynamic therapy (PDT) for idiopathic polypoidal choroidal vasculopathy (IPCV). DESIGN: Interventional case report. METHODS: A pseudophakic 84-year-old-woman had IPCV and decreased vision. Angiography demonstrated macular leakage. PDT with verteporfin was applied. Two days later, visual acuity decreased from 20/50 to 20/400. Examination revealed extensive inferior subretinal fluid, which mimicked a pseudophakic rhegmatogenous retinal detachment. A scleral buckle was placed; no retinal breaks were identified. RESULTS: Vision and fluid resolved over three weeks. Four months later, examination revealed decreased vision and persistent leakage. Two days after repeat PDT, bullous exudative macular detachment recurred. Detachment resolved over two weeks; visual acuity returned to 20/50. CONCLUSION: IPCV that is treated with PDT may be complicated by iatrogenic bullous exudative retinal detachments that resemble rhegmatogenous detachments. Modified treatment parameters may reduce the risk of recurrence. The natural history likely includes spontaneous resolution and visual recovery.

Acute Disease↗
PubMed2005

Dynamic atypical optic nerve coloboma associated with transient macular detachment.

PURPOSE: Macular schisis or detachment is frequently observed in eyes with optic pits or colobomas. Although spontaneous resolution of the maculopathy has been reported, concurrent changes in the optic nerve coloboma have not. We report three cases of atypical optic nerve colobomas in which dynamic optic nerve changes coincide with the development and subsequent resolution of the associated maculopathy. METHODS: We reviewed the records of three patients with dynamic optic nerve changes associated with maculopathy. All patients were observed for at least 6 months. Fundus photography and fluorescein angiography were used to document the optic nerve and macular changes. RESULTS: Three patients were noted to have macular detachments without apparent optic nerve excavation. With observation, the maculopathy spontaneously resolved in each case. We documented concurrent optic nerve changes whereby atypical optic nerve colobomas became apparent over several months in all cases. In one case, we noted the simultaneous development of maculopathy in association with obscuration of a prior disc anomaly. None of the eyes had a posterior vitreous detachment. We could not identify any associated systemic conditions or reproduce the findings with external stimulation. Initial Snellen acuity ranged from 20/60 to 20/200. Final Snellen acuity ranged from 20/20 to 20/40. CONCLUSIONS: Fluctuating optic nerve changes may occur in the setting of atypical optic nerve coloboma and associated maculopathy. In cases of macular schisis or detachment where an optic nerve coloboma is not readily apparent, and no other causes are identified, consideration of a period of observation prior to therapeutic intervention seems appropriate.

Adult↗
PubMed2004

Intravitreally injected human immunoglobulin attenuates the effects of Staphylococcus aureus culture supernatant in a rabbit model of toxin-mediated endophthalmitis.

OBJECTIVE: To determine whether human immunoglobulin attenuates the toxic effects of Staphylococcus aureus culture supernatant in a rabbit model of endophthalmitis. METHODS: Immunoglobulin binding to products of S aureus strain RN4220 was tested by Western blot analysis using known toxins (beta-hemolysin and toxic shock syndrome toxin-1) and a concentrated culture supernatant containing S aureus exotoxins (pooled toxin). To induce endophthalmitis, pooled toxin was injected into the rabbit vitreous. For immunoglobulin treatment, immunoglobulin and pooled toxin were either mixed and injected simultaneously or immunoglobulin was injected immediately after or 6 hours after pooled toxin injection. Severity of endophthalmitis was graded according to a 9-day course with clinical examination (slitlamp biomicroscopy or indirect ophthalmoscopy) and evaluation of histologic sections. RESULTS: The toxic effects of pooled toxin were markedly reduced when immunoglobulin was mixed with pooled toxin and injected simultaneously. Delayed injection of immunoglobulin diminished its ability to reduce toxicity. Clinical and histologic signs of toxicity were partially attenuated when immunoglobulin was injected immediately after pooled toxin, but only minimal clinically detectable reductions in toxicity were observed when immunoglobulin injection was delayed for 6 hours. CONCLUSION: Pooled human immunoglobulin can attenuate the toxic intravitreal effects of a concentrated culture supernatant containing S aureus exotoxins. Clinical Relevance Immunoglobulin may represent a novel adjuvant in the treatment of bacterial endophthalmitis. To optimize the potential therapeutic benefit, maximizing the mixture of immunoglobulin with bacterial products and early intervention are likely to be important.

Animals↗
PubMed2004

Subconjunctival antibiotics for acute postcataract extraction endophthalmitis--is it necessary?

PURPOSE: To evaluate the efficacy of adjunctive subconjunctival antibiotic injection in the treatment of acute postcataract extraction endophthalmitis. DESIGN: Retrospective cohort study. METHODS: Patients who presented with hand motions or better vision and received subconjunctival antibiotics (SC+ group) were compared with those who did not (SC- group) in the treatment of acute postoperative endophthalmitis. RESULTS: The rate of obtaining a final vision of 20/40 or better was 60% in the SC+ group (n = 25) compared with 72% in the SC- group (n = 18) (P =.69), and the mean change in logMAR was -1.36 (improvement) versus -1.34 (P =.93). Based on a linear regression model controlling for presenting vision, there was no statistical difference in the mean logMAR change between the two groups (P =.73). CONCLUSION: Subconjunctival antibiotic injection as an adjunct to intravitreal antibiotics was unassociated with treatment benefit in patients with acute postoperative endophthalmitis presenting with vision of hand motions or better.

Acute Disease↗
PubMed2004

Intravitreal human immune globulin in a rabbit model of Staphylococcus aureus toxin-mediated endophthalmitis: a potential adjunct in the treatment of endophthalmitis.

OBJECTIVES: To test the feasibility of human immune globulin (IG, Gamimune N, 10%) as a new treatment for endophthalmitis, the ocular tolerance, distribution, and ability of intravitreal IG to attenuate the toxic effects of Staphylococcus aureus culture supernatant were evaluated in a rabbit model. METHODS: Effects of intravitreally injected IG were assessed histologically and with Western blot analysis performed 1 to 5 days after injection. IG reactivity to products of S. aureus strain RN4220 was tested by Western blotting, using known toxins (beta hemolysin and toxic shock syndrome toxin-1) and a concentrated culture supernatant containing S. aureus exotoxins (pooled toxin, PT). Endophthalmitis was induced by intravitreal PT injection. For treatment, IG and PT were mixed and injected simultaneously, or IG was injected immediately after, or 6 hours after, PT injection. PT toxicity was graded clinically and histologically over 9 days. RESULTS: IG persisted intravitreally at least 5 days, inducing no clinical inflammation and minimal mononuclear cell infiltration. In the endophthalmitis model, toxicity from PT was significantly reduced when IG was mixed with PT and injected simultaneously, or when IG was delivered immediately after PT. Only minimal clinically detectable reductions were observed when IG delivery was delayed 6 hours. CONCLUSIONS: Intravitreal IG is well tolerated in the rabbit eye and attenuates the toxicity of culture supernatant containing S. aureus exotoxins. Because toxin elaboration likely occurs gradually in true infection, reduced effects observed with delayed treatment in this toxin-injected model do not preclude clinical application. IG may represent a novel adjunct in endophthalmitis treatment.

Animals↗
PubMed2003

Arteriovenous crossing dissection without separation of the retina vessels for treatment of branch retinal vein occlusion.

PURPOSE: To evaluate visual outcome after arteriovenous (AV) crossing dissection for the treatment of branch retinal vein occlusion (BRVO) and secondary macular dysfunction in which difficulty separating the retinal vessels was experienced. METHODS: A pars plana vitrectomy and dissection of the involved AV crossing site were performed consecutively in 20 eyes of 20 patients with BRVO and vision loss. The overlying retinal artery was dissected free from the retinal surface, and separation of the artery and vein at the crossing site was attempted. RESULTS: In 19 of 20 eyes, the retinal artery was dissected around the crossing site, but a marked adhesion between the artery and vein precluded separation. After a mean follow-up of 10.5 months, VA improved by at least two lines in 16 eyes (80%), remained unchanged in three eyes (10%), and worsened by at least two lines in three eyes (10%). Mean change (+/- SE) in logMAR acuity was -0.28 +/- 0.11 (two or three lines of improvement, P = 0.016) at 1 to 2 months' follow-up and -0.44 +/- 0.14 (three or four lines of improvement, P = 0.008) at the final follow-up. Cataract formation or progression occurred in 88%. CONCLUSIONS: A surgically important adhesion between the retinal artery and vein at proximal AV crossings was encountered in all eyes undergoing AV crossing dissection, correlating with previous histologic and cadaver eye studies. Cataract formation or worsening was a frequent complication. Visual improvement may occur after vitrectomy and AV crossing dissection without separation of the retinal vessels.

Adult↗
PubMed2002

Subtenon's depot corticosteroid injections in patients with a history of corticosteroid-induced intraocular pressure elevation.

PURPOSE: To determine whether a history of intraocular pressure elevation from local corticosteroid administration could predict subsequent intraocular pressure elevation after posterior subtenon's corticosteroid injection. METHODS: A retrospective review was performed of 64 consecutive patients (64 eyes) receiving posterior subtenon's corticosteroid injection. Patients were categorized as either historical corticosteroid responders or nonresponders based on intraocular pressure response to topical corticosteroid drops in the same eye or to previous posterior subtenon's corticosteroid injection of the fellow eye. Historical responders were defined as having a relative intraocular pressure increase of 5 mm Hg and absolute intraocular pressure greater than 24 mm Hg with an anatomically open angle. Relative risk of intraocular pressure elevation was evaluated based on historical response and presenting diagnosis. RESULTS: Nine eyes were historical responders, and 55 eyes were historical nonresponders. A higher rate of recurrent intraocular pressure elevation developed in historical responder eyes (4 of 9, 44%) compared with nonresponders (7 of 55, 13%) after posterior subtenon's injection (P = .04, Fisher's test; P = .07, Kaplan-Meier analysis). Historical responders with uveitis were at significantly higher risk of intraocular pressure elevation than nonresponders without uveitis (hazard ratio = 10.8, P = .04, Cox proportional hazards). All but one eye that developed intraocular pressure elevation from posterior subtenon's injection was adequately controlled with topical antiglaucoma therapy. CONCLUSION: In nonglaucomatous eyes, a previous history of corticosteroid-induced intraocular pressure elevation is a relative, not absolute, contraindication to posterior subtenon's corticosteroid injection, because the risk of intraocular pressure elevation is not absolute, and because it can usually be well controlled with topical antiglaucoma therapy.

Adult↗
PubMedDate not supplied

Diabetic macular edema associated with glitazone use.

PURPOSE: To describe diabetic macular edema (DME) in patients who developed fluid retention as a consequence of glitazone use. METHODS: A chart review identified 30 patients who used pioglitazone or rosiglitazone and had both lower extremity edema and macular edema. Clinical reports, photographs, and fluorescein angiograms were reviewed. Patients followed for >3 months were analyzed separately. RESULTS: Seventeen patients took oral pioglitazone, 11 took rosiglitazone, and 2 took both drugs at different times. Eleven patients were observed for >3 months after cessation of glitazones. Mean weight gain during drug administration in this group was 30 lb, and mean weight loss after drug discontinuation was 19 lb. Rapid reduction in macular edema off drug occurred in only 4 of 11 patients, but 8 of 11 had reduced edema over 2 years. Mean visual acuity in this group at the initial visit was 20/60, and at the final visit, it was 20/85. Four eyes of three patients had resolution of diffuse macular edema with improved vision after cessation of glitazones without laser treatment. CONCLUSIONS: Fluid retention occurs in 5% to 15% of patients taking glitazones. In some of these patients, glitazone use appears to be a cause of macular edema, and drug cessation appears to result in rapid resolution of both peripheral and macular edema. Fluid retention associated with glitazone use should be considered when assessing treatment options for patients with DME, especially those with concomitant peripheral edema.

Administration, Oral↗
PubMedDate not supplied

Transpupillary thermotherapy with indocyanine green dye enhancement for the treatment of occult subfoveal choroidal neovascularization in age-related macular degeneration.

BACKGROUND AND OBJECTIVES: Transpupillary thermotherapy (TTT) with indocyanine green (ICG) dye enhancement (TTT+) and TTT alone were compared for safety and effectiveness as a treatment of occult subfoveal choroidal neovascularization in age-related macular degeneration. PATIENTS AND METHODS: Twenty-one patients were randomized to receive TTT (12 eyes) or TTT+ (9 eyes) and observed for at least 6 months. ETDRS visual acuity and fluorescein and ICG angiography were obtained every 3 months. RESULTS: The median initial visual acuity was 20/80 in the TTT group and 20/100 in the TTT+ group. At 6 months, loss of less than 3 lines of visual acuity was present in 7 of 12 eyes (58%) in the TTT group and 5 of 9 eyes (56%) in the TTT+ group. At the final examination, there was no active choroidal neovascularization exudation in 6 of 12 eyes (50%) in the TTT group and 5 of 9 eyes (56%) in the TTT+ group. The median final visual acuity was 20/125 in the TTT group and 20/160 in the TTT+ group. Ocular or systemic complications were not encountered in either group. CONCLUSION: TTT with ICG dye enhancement was as safe and effective as TTT alone in this study. However, modifications of treatment protocol would be needed to see whether there is any advantage to using ICG dye enhancement.

Aged↗
PubMedDate not supplied

Fluorescein angiographic findings in an infected scleral buckle.

This report presents fluorescein angiographic (FA) findings in a patient with scleral buckle infection. Ten days following scleral buckling surgery, FA demonstrated dilated choroidal vessels over the buckle with leakage of fluorescein into the subretinal space. Irregular diffuse scleral thickening was noted on the computed tomography (CT). The findings of focal choroiditis with dilated leaky choroidal vessels seen on FA, or diffuse scleral thickening demonstrated by a CT may aid in establishing the diagnosis of scleral buckle infection.

Anti-Bacterial Agents↗