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Biomedical subjects

D P Han

Publications and source records attributed to D P Han.

At least 55 records · Page 3Linked to original sources
PubMed1995

Premacular hemorrhage as a sign of subacute bacterial endocarditis.

PURPOSE/METHODS: We examined a patient with mitral valve insufficiency, a sudden decrease in vision in the right eye, and premacular hemorrhage, which was a sign of subacute bacterial endocarditis. RESULTS/CONCLUSION: The patient was hospitalized and treated with intravenous antibiotics. Blood cultures grew Streptococcus viridans. Ocular symptoms and signs improved over two months. Premacular hemorrhage may be a sign of subacute bacterial endocarditis and may obscure other classic signs. Subacute bacterial endocarditis should be included in the differential diagnosis of premacular hemorrhage.

Acute Disease↗
PubMed1995

Reversible loss of light perception after vitreoretinal surgery.

PURPOSE: We studied reversible loss of light perception after vitreoretinal surgery to show that functional vision can return in some patients. METHODS: We reviewed the medical records of seven patients who had postoperative reversible loss of light perception in the eye that underwent vitreoretinal surgery. Differences in the postoperative courses and interventions were studied. RESULTS: Five of the seven patients had diabetes mellitus but none had hypertension. The indications for vitreoretinal surgery were severe proliferative diabetic retinopathy in five patients and retinal detachment with advanced proliferative vitreoretinopathy in two patients. Seven patients had reversible loss of light perception within the first three postoperative days. Six of the seven patients had an intraocular pressure greater than 26 mm Hg at the time the eye had no light perception. Decreasing the intraocular pressure was associated with return of light perception in five of seven patients. Return of useful vision was gradual. Four of seven patients had a visual acuity of 20/400 or better one month after surgery, and all seven had a visual acuity of 20/400 or better three months after surgery. Visual acuity in four eyes improved further to 20/70 or better at six months or more after surgery. CONCLUSION: Reversible loss of light perception after vitreoretinal surgery does occur in some patients. Monitoring vision and intraocular pressure is important because prompt treatment may assist in the recovery of functional vision.

Adult↗
PubMed1995

Combined pars plana vitrectomy-lensectomy and open-loop anterior chamber lens implantation.

PURPOSE: To investigate the effectiveness of open-loop, one-piece, flexible, Kelman-style, all-polymethylmethacrylate (PMMA) anterior chamber intraocular lenses (AC IOLs) in patients undergoing pars plana vitrectomy surgery for a variety of vitreoretinal disorders. METHODS: Fifteen patients (6 women and 9 men) underwent combined pars plana vitrectomy with insertion of an open-loop AC IOL. Postoperative results were evaluated. RESULTS: The average preoperative visual acuity of 20/360 (logMAR scale, 1.25 +/- 0.80) improved to 20/52 (logMAR scale, 0.42 +/- 0.35) after an average follow-up of 10.2 months (range, 1-41 months). Of 15 eyes, 7 (47%) achieved a visual acuity of better than 20/40. There was no evidence of glaucoma exacerbation or corneal decompensation. Visual acuity was limited primarily by chronic cystoid macular edema in 4 (27%) of 15 eyes. CONCLUSION: In this preliminary series of patients, open-loop, flexible, all-PMMA, Kelman-style AC IOLs appear to be well tolerated and represent a viable, simple alternative to transscleral fixation of a posterior chamber IOL or surgical aphakia in patients undergoing vitrectomy surgery.

Adult↗
PubMed1995

Antisense GLUT1 RNA suppresses the transforming phenotypes of NIH 3T3 cells transformed by N-Ras.

An antisense approach was attempted to investigate the role of antisense GLUT1 RNA in suppressing tumor cell phenotypes using N-ras-transformed NIH 3T3 cells. The established cell line transformed by ras showed typical biological characteristics of cancer cells, such as increased glucose transport, GLUT1 mRNA contents, and the ability to form colonies on the soft agar. In this system, the plasmids (pMAM-GLUT1(rev)) which can transcribe the antisense GLUT1 RNA were transfected and the accompanying changes in the phenotypes of the ras-transformed cells were observed. The expression of antisense GLUT1 RNA by induction with dexamethasone reduced the glucose transport by 30% (1.97 +/- 0.13 nmoles) after 4 min incubation when compared to the non-induction group of transformed cell (2.85 +/- 0.19 nmoles). Also, the number of colonies sized over 50 microns on the soft agar was reduced significantly in the antisense RNA expressing group compared to non-induction group. These results suggest that the expression of antisense GLUT1 RNA reduced the glucose transport and transforming potential in soft agar possibly by hybridization with GLUT1 mRNA in N-ras-transformed NIH 3T3 cells.

3T3 Cells↗
PubMed1994

Management of complex retinal detachment with combined relaxing retinotomy and intravitreal perfluoro-n-octane injection.

We evaluated intravitreal perfluoro-n-octane injection for the positioning of large retinal flaps after relaxing retinotomies. Nineteen eyes underwent vitrectomy for advanced retinal detachments from proliferative vitreoretinopathy (11 eyes), trauma (five eyes), and proliferative diabetic retinopathy (three eyes). After retinotomy and complete relief of traction, injection of perfluoro-n-octane to a level anterior to the retinotomy edge was used to remove subretinal fluid thoroughly from beneath the retinal flap. All irrigation fluid anterior to the perfluoro-n-octane meniscus was aspirated before perfluoro-n-octane removal. Final tamponade was obtained with gas (four eyes) or silicone oil (15 eyes). After six to 17 eyes) or silicone oil (15 eyes). After six to 17 months of follow-up, the retinas were attached in 13 eyes (68%), and visual acuity of 5/200 or better was obtained in eight eyes (42%). Subretinal migration of perfluoro-n-octane and posterior slippage of the retinal flap occurred during perfluoro-n-octane/silicone oil exchange in one eye. No other complications were detected. Perfluoro-n-octane injection is an effective technique for positioning large retinal flaps after relaxing retinotomy.

Adolescent↗
PubMed1994

The effects of silicone oil removal. Silicone Study Report 6.

OBJECTIVE: To evaluate the advisability of removing silicone oil from eyes after surgery for severe (with a classification of at least C-3) proliferative vitreoretinopathy. DESIGN: Subgroup analysis of the Silicone Study, a randomized, multicentered, surgical trial. SETTING: Community- and university-based clinics. PATIENTS: Two hundred twenty-two eyes with severe proliferative vitreoretinopathy followed up in the Silicone Study. INTERVENTIONS: Vitrectomy for proliferative vitreoretinopathy with silicone oil as the intraocular tamponade. OUTCOME MEASURES: Changes in visual acuity, recurrent retinal detachment, and incidence of complications. RESULTS: Ninety-nine (45%) of 222 eyes had surgery for silicone oil removal (oil-removed eyes). Compared with the eyes that did not undergo silicone oil removal (oil-retained eyes) evaluated at a comparable time after oil injection, oil-removed eyes at the examination prior to oil removal were more likely to be attached (85% vs 40%; P < .0001), have a visual acuity of 5/200 or greater (63% vs 35%; P < .0001), and not be hypotonous (5% vs 22%; P < .001). There was no association between the length of oil retention and incidence of recurrent retinal detachment after oil removal. Eyes with attached retinas at the time of oil removal generally improved in visual acuity at the last follow-up examination (P < .0001), which was not evident in eyes with detached retinas at the time of oil removal. In a matched-pair cohort analysis comparing both sets of eyes, there was an increased risk for recurrent retinal detachment at the last follow-up examination in the oil-removed eyes (odds ratio [OR], 2.1; P = .09). However, overall visual acuity improved for oil-removed eyes in 19 (29%) of 66 pairs and for oil-retained eyes in one (2%) of 66 pairs (OR, 19.0; P < .0001). Although nonsignificant, incidence rates of keratopathy (OR, 0.5) and hypotony (OR, 0.5) were lower in oil-removed eyes. CONCLUSION: Removal of silicone oil in anatomically successful eyes significantly increases the likelihood of improved visual acuity with a slight increase in the likelihood of recurrent retinal redetachment. There was a trend for a reduction in the incidence of complications in the oil-removed eyes.

Adult↗
PubMed1994

Segmental infarction of the testicle: atypical presentation of a testicular mass.

Segmental infarction of the testis represents a rare entity. To our knowledge 11 cases have been reported in the literature. We report 4 additional cases of segmental testicular infarction masquerading as testis tumors. Inability to distinguish these benign lesions from malignant testis tumors resulted in orchiectomy in all 4 cases.

Adult↗
PubMed1994

A modified en bloc excision technique during vitrectomy for diabetic traction retinal detachment. Results and complications.

PURPOSE: The visual results and complications were determined for a modified en bloc excision technique for management of diabetic traction macular detachment. PATIENTS AND METHODS: A consecutive series of 30 eyes with this condition underwent pars plana vitrectomy, during which all posterior hyaloid except for portions essential for membrane dissection were excised. Bimanual dissection techniques then allowed excision of fibrovascular membranes "en bloc" with the retained hyaloid. RESULTS: After 6 to 44 months of follow-up, visual acuity of 5/200 or better was obtained in 23 (77%) of 30 eyes, with complete reattachment in 29 (97%) of 30 eyes. Iatrogenic retinal breaks occurred in 6 (20%) of 30 eyes. Two eyes required repeat vitrectomy. CONCLUSIONS: The modified en bloc excision technique allowed similar visual outcome, a higher reattachment rate, and less postoperative morbidity than previously reported surgical approaches to diabetic traction macular detachment.

Adult↗
PubMed1994

Evaluation of anterior segment tolerance to short-term intravitreal perfluoron.

PURPOSE: A study was performed to evaluate corneal and anterior segment toxicity from short-term (24-hour) intravitreal use of perfluoro-n-octane. METHODS: Forty aphakic, vitrectomized eyes of pigmented rabbits underwent intravitreal injection of either 0.5 ml of perfluoro-n-octane (Perfluoron; Infinitech, St. Louis, MO; treated) or 0.5 ml balanced saline solution (control). Perfluoron was allowed to remain in the vitreous cavity for 24 hours. Serial measurements of corneal pachymetry and pneumotonometry were performed at 1, 4, 12, and 24 hours after injection. After 24 hours, endothelial cell morphology and barrier function were evaluated. RESULTS: No significant differences in corneal thickness or intraocular pressure were noted between the two groups at any of the time points studied, and no differences in endothelial cell density/hexagonality or endothelial cell barrier function were observed 24 hours after injection. CONCLUSIONS: In the absence of sustained corneal contact, no evidence of significant acute corneal or anterior segment toxicity was observed in response to short-term intravitreal perfluoro-n-octane in aphakic, vitrectomized rabbit eyes.

Animals↗
PubMed1994

Postoperative fibrin formation and visual outcome after pars plana vitrectomy.

PURPOSE: To determine whether postvitrectomy fibrin formation was associated with visual outcome, a prospective study of patients undergoing pars plana vitrectomy was performed. METHODS: In 121 patients undergoing vitrectomy at the Medical College of Wisconsin between July 1986 and April 1989, the association of fibrin formation and other perioperative factors with visual outcome was evaluated by univariate and multivariate regression analysis. Poor visual outcome was defined as visual acuity worse than 5/200. RESULTS: After a median follow-up period of 23 months (range 6 to 51 months), patients with severe fibrin formation experienced a higher rate of poor visual outcome (19 of 26 patients, 73%) than patients with little or no fibrin formation (23 of 95 patients, 24%; P < 0.0001, univariate analysis). After adjusting for a variety of factors with multivariate regression analysis, fibrin formation was not significantly predictive of final visual outcome. CONCLUSIONS: Factors associated with postvitrectomy fibrin formation may affect visual outcome more than fibrin formation itself.

Adolescent↗
PubMed1993

Perioperative choroidal hemorrhage at pars plana vitrectomy. A case-control study.

PURPOSE: Risk factors for choroidal hemorrhage during pars plana vitrectomy surgery are currently not well defined. The authors analyzed potential risk factors for perioperative choroidal hemorrhage at pars plana vitrectomy in a case-control study. METHODS: Of 683 consecutive vitrectomy procedures, 13 cases of choroidal hemorrhage were identified in the operative or immediate postoperative period. Fifty vitrectomy controls from the same period were randomly selected and were compared with the hemorrhage cases by univariate analysis with respect to various potential risk factors. RESULTS: The incidence of choroidal hemorrhage associated with vitrectomy was 1.9%. Statistically significant risks (P < or = 0.05) included: greater age (mean, 70.9 versus 52.1 years); elevated preoperative pressure (19.9 versus 13.0 mmHg); preoperative diagnosis of rhegmatogenous retinal detachment (relative risk, 8.1); aphakic or pseudophakic status (relative risk, 5.2); and scleral buckle procedure at vitrectomy (relative risk, 12.0). Eyes with previous ocular trauma and previous vitrectomy had a reduced risk of choroidal hemorrhage. The incidence of severe visual loss (final visual acuity < 5/200) did not differ significantly from controls. CONCLUSIONS: Significant risk factors for choroidal hemorrhage are identified in this study which may help to identify patients at increased risk for this complication. Good visual outcome is possible after choroidal hemorrhage at vitrectomy (69% with visual acuity > 5/200).

Aged↗
PubMed1993

Choroidal rupture and optic atrophy.

The association between post-traumatic optic disc pallor and traumatic choroidal rupture is poorly understood. To further define this relationship, nine cases of indirect traumatic choroidal rupture and post-traumatic optic disc pallor were compared with cases of indirect choroidal rupture without disc pallor in terms of severity of ocular injury, fundus findings, and visual outcome. The type and severity of the injury did not appear to influence the risk of optic disc pallor. Optic disc pallor was associated with a slightly poorer long term visual acuity than eyes without pallor (p = 0.059). The presence of a relative afferent pupillary defect was strongly associated with optic disc pallor (p = 0.016). Peripapillary retinal pigment epithelial abnormalities were a common finding, suggesting peripapillary trauma as a cause for optic disc pallor.

Adolescent↗
PubMed1993

Perfluoropropane 12% versus 20%. Effect on intraocular pressure and gas tamponade after pars plana vitrectomy.

A randomized prospective study was performed on 30 nonglaucomatous eyes undergoing pars plana vitrectomy and intraoperative fluid-gas exchange, comparing the effect of two perfluoropropane gas concentrations (12% and 20%) on postoperative intraocular pressure, early postoperative bubble size, and intravitreal longevity. No significant differences in mean intraocular bubble size at 36 to 48 hours and mean peak and final follow-up intraocular pressure were found between the 12% group (n = 15) and the 20% group (n = 15, unpaired T-test). Intravitreal longevity was significantly greater for the 20% concentration (mean +/- standard deviation = 8.4 +/- 1.8 weeks) compared with the 12% concentration (mean +/- standard deviation = 6.7 +/- 1.6 weeks). In nonglaucomatous eyes under careful observation and appropriate antiglaucoma therapy, the choice between a 12% or 20% concentration of perfluoropropane gas determined primarily longevity of gas tamponade rather than postoperative pressure or early bubble size.

Double-Blind Method↗
PubMed1992

Macular phototoxicity caused by fiberoptic endoillumination during pars plana vitrectomy.

Three cases of retinal phototoxicity were caused by light from the endoilluminator used in vitrectomy. Preoperative clinical examination, color photography, and fluorescein angiography in all three cases failed to disclose retinal pigment epithelial changes. Postoperative clinical findings, photographs, and fluorescein angiograms are highly suggestive of the presence of retinal phototoxicity. The characteristics of these lesions and surgical conditions implicate the endoilluminator as the source of photic injury. The macular lesions were noted within one week of the surgical procedure, measured between 2 and 5 disk diameters in size, involved the fovea in two eyes, and resulted in marked decrease in visual acuity in two of three eyes, with persistence in one eye. Initially, whitening of the outer retina was present, but was replaced by pigmentary mottling at the level of the retinal pigment epithelium within a few weeks. Preventive measures to avoid macular phototoxicity associated with vitrectomy are discussed.

Adult↗
PubMed1992

Submacular fibrosis after photocoagulation for diabetic macular edema.

Ten eyes of nine patients developed submacular fibrotic scars without fluorescein angiographic evidence of choroidal neovascularization between two and 11 months (mean, 6.1 months) after argon laser treatment for diabetic macular edema. In four eyes, development of the subretinal scar was associated with visual acuity loss of two, two, four, and eight lines of Snellen visual acuity, respectively, within five to 11 months of laser treatment. At the final follow-up visit, the visual acuity of the eyes with two lines of visual acuity loss had returned to within one line of the initial value, but the visual acuity of the eyes with more severe initial visual acuity loss did not recover notably. In four eyes, fibrous submacular strands extended from macular laser scars, suggesting an iatrogenic role of the laser in inducing this complication.

Aged↗