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Brooks W McCuen

Publications and source records attributed to Brooks W McCuen.

11 recordsLinked to original sources
PubMed2007

Natural history of foveolar lucencies observed by optical coherence tomography after macular hole surgery.

PURPOSE: To describe the incidence, course, and anatomic and functional outcomes of foveolar lucencies observed by optical coherence tomography after macular hole surgery. METHODS: Retrospective chart review of all idiopathic macular hole surgeries performed between February 2002 and August 2003. Available data involving eyes with foveolar lucencies after macular hole surgery were collected regarding best-corrected visual acuity, lens status, slit-lamp biomicroscopy, and optical coherence tomography before and at follow-up visits ranging from 1 week to 27 months after macular hole surgery. RESULTS: Thirty-five eyes of 35 patients were identified. Foveolar lucencies were detected by optical coherence tomography in 9 of the 35 eyes (26%). Operative procedures included creation of a posterior vitreous detachment in 8 eyes and indocyanine green-assisted internal limiting membrane peeling in 5 eyes. Intraocular tamponade consisted of 30% sulfur hexafluoride gas in 6 eyes and 20% perfluoropropane gas in 3 eyes with at least 1 week of face-down positioning. Postoperative visual acuity showed gradual improvement coinciding with decreasing size and eventual disappearance (3 to 11 months) of the foveolar lucency. CONCLUSION: Foveolar lucencies observed by optical coherence tomography are a common finding after macular hole surgery (26%). They occur with and without indocyanine green-assisted internal limiting membrane peeling. Earlier disappearance of the foveolar lucency does not correlate with the type of gas used for tamponade. They gradually decrease and eventually resolve with time without additional surgical intervention and with further improvement of visual acuity.

Aged↗
PubMed2005

A prospective, open-label, dose-escalating study of low molecular weight heparin during repeat vitrectomy for PVR and severe diabetic retinopathy.

BACKGROUND: To determine the maximum tolerated dose (MTD) of enoxaparin, a low molecular weight heparin (LMWH) was used during repeat vitrectomy for rhegmatogenous retinal detachment with proliferative vitreoretinopathy (PVR) and severe diabetic retinopathy. METHODS: From 25 patients, 29 eyes undergoing repeat vitrectomy for PVR (CP3 or greater) or severe diabetic retinopathy were included in the study. Patients had previously undergone an average of 2.1 previous vitrectomies (range 1-5). Enoxaparin was added to the infusion fluid in an escalating dose from 0.1 IU/ml to 6.0 IU/ml as tolerated. Intraoperative bleeding, postoperative fibrin, hyphema and vitreous hemorrhage were graded in an unmasked fashion using previously described grading scales. RESULTS: All patients completed the study, and the study was able to achieve the 6.0 IU/ml maximum dose on the dose escalation schedule. No patient experienced dose-limiting toxicity. Analysis showed no increase in intraoperative bleeding complications between low dose ( 1.0 IU/ml) enoxaparin (Mann-Whitney Test, P=0.029). CONCLUSIONS: Enoxaparin dose escalation did not result in a dose-dependent increase in acute side effects. The establishment of a well-tolerated dose of enoxaparin during repeat vitrectomy for PVR and severe diabetic retinopathy (6.0 IU/ml) provides a foundation for future studies.

Diabetic Retinopathy↗
PubMed2004

Radial optic neurotomy in the porcine eye without retinal vein occlusion.

OBJECTIVE: To demonstrate the histopathologic changes in the porcine eye without retinal vein occlusion after radial optic neurotomy (RON). METHODS: A RON was performed in 14 normal eyes of 12 Yorkshire Cross pigs. One radial stab incision at the edge of the nasal optic nerve head was made using a 20-gauge microvitreoretinal blade (Visitec) while the intraocular pressure was elevated. Surgery was concluded when hemostasis was achieved. Weekly ophthalmoscopic examinations were performed. Group 1 eyes (4 eyes of 2 pigs) were enucleated at the end of surgery. Group 2 eyes (4 eyes of 4 pigs) were enucleated 1 week postoperatively, and group 3 eyes (4 eyes of 4 pigs) were enucleated 3 weeks postoperatively. In group 4 (2 eyes of 2 pigs), animals underwent vitrectomy and RON, and eyes were enucleated 3 weeks postoperatively. RESULTS: Ophthalmoscopic examination demonstrated engorged blood vessels at the RON site up to 3 weeks after surgery with minimal or no hemorrhage. Histological examination of the optic nerve demonstrated foci of hemorrhage, interstitial edema, reactive gliosis, and rare inflammatory cells. At 3 weeks, there was complete axonal nerve fiber loss distal to the neurotomy site. CONCLUSIONS: After RON, marked gliosis and complete axonal nerve fiber loss occur at the neurotomy site. Although bleeding was rare intraoperatively in this porcine model, hemorrhage and interstitial edema were present within the optic nerve at the neurotomy site histologically. Clinical Relevance Radial optic neurotomy remains a controversial method of treatment for central retinal vein occlusion. To our knowledge, this is the first study in the literature describing the histopathologic findings after RON.

Animals↗
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

Comparison of silicone oil versus gas tamponade in the treatment of idiopathic full-thickness macular hole.

PURPOSE: To compare anatomic and functional outcomes of macular hole surgery with either silicone oil or C(3)F(8) gas tamponade. DESIGN: Retrospective comparative interventional study. PARTICIPANTS: Fifty-four eyes of 51 patients underwent pars plana vitrectomy for macular holes. Thirty-one eyes were treated with silicone oil tamponade, and 23 eyes were treated with C(3)F(8) tamponade. METHODS: Demographics, preoperative and postoperative characteristics, and complications were analyzed. MAIN OUTCOME MEASURES: Preoperative and postoperative visual acuity, initial hole closure, number of persistent or recurrent holes, number of reoperations, and final hole closure. RESULTS: The silicone oil and gas tamponade groups were demographically similar. The rate of hole closure after one operation with oil tamponade was significantly lower than that with gas tamponade (65% vs. 91%; P = 0.022). The percentage of patients undergoing a second operation was significantly higher in the oil group (35% vs. 4%; P = 0.006). However, with reoperations, the final rate of hole closure was similar between the oil and gas groups (90% vs. 96%; P = 0.628). The final median visual acuity for the gas group was significantly better than for the oil group (20/50 vs. 20/70; P = 0.047). CONCLUSIONS: C(3)F(8) gas proved to be a more effective tamponade than silicone oil with respect to achieving initial closure of macular holes. Eyes receiving an oil tamponade required significantly more reoperations to achieve a similar rate of hole closure compared with eyes undergoing a gas tamponade. Final visual acuity was better for gas-operated eyes than for silicone-operated eyes.

Aged↗
PubMed2002

RGD peptide-assisted vitrectomy to facilitate induction of a posterior vitreous detachment: a new principle in pharmacological vitreolysis.

PURPOSE: To evaluate a new concept in pharmacological vitreolysis by studying the efficacy of intravitreal RGD peptide-assisted vitrectomy in facilitating the separation of the posterior cortical vitreous from the retinal surface in an animal model. METHODS: Eight rabbits (16 eyes) received an intravitreal injection of 1 or 5 mg of RGD peptide in one eye and either RGE peptide (inactive control) or phosphate buffered saline in the fellow eye. After 24 hours, a pars plana vitrectomy with low aspiration (< or =30 mmHg) was performed in an attempt to create a detachment of the posterior cortical vitreous. A masked observer performed pre- and postoperative indirect ophthalmoscopy and B-scan ultrasonography. Postoperative scanning electron microscopy evaluated the vitreoretinal surface in selected eyes. Two additional rabbits received intravitreal injections of RGD peptide in one eye (1 mg and 5 mg) and 1 mg of RGE peptide in the fellow eye to examine apoptosis of the retinal cells by TUNEL assay. RESULTS: Based on postoperative ultrasound findings, six of the eight rabbits had a greater degree of posterior vitreous detachment in the RGD eye compared to the fellow eye (p = 0.03). The total number and the average number of detached quadrants in the group of RGD peptide eyes was twenty-three and 2.85 respectively compared to seven and 0.85 for the control fellow eyes (p = 0.02). Scanning electron microscopy confirmed the presence of postoperative posterior vitreous detachment. There was no evidence of retinal cell apoptosis in RGD injected eyes. CONCLUSION: RGD peptide-assisted vitrectomy facilitated posterior vitreous detachment in rabbit eyes, suggesting that RGD-containing peptides may prove to be effective adjuncts in producing posterior vitreous separation during vitreous surgery.

Animals↗