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Biomedical subjects

B W McCuen

Publications and source records attributed to B W McCuen.

At least 19 recordsLinked to original sources
PubMed1992

Efficacy of fluid-air exchange for postvitrectomy diabetic vitreous hemorrhage.

We reviewed the records of 33 fluid-air exchanges to assess the efficacy of fluid-air exchange in the management of recurrent vitreous cavity hemorrhage after vitrectomy for proliferative diabetic retinopathy. Fluid-air exchange alone was successful in clearing the vitreous cavity in ten of 20 eyes after a mean of 1.5 exchanges per eye. Repeat vitrectomy was required in the remaining ten eyes and anterior hyaloidal fibrovascular proliferation was frequently found. Hemorrhages that occurred in the late postoperative period (more than nine months) appeared more likely to be successfully treated with fluid-air exchange alone. Failure of the initial fluid-air exchange to induce clearing immediately after the procedure appeared to be associated with subsequent exchange failures and need for surgical intervention. Complications from the exchange procedure were infrequent with the development of peripheral retinal detachment in one eye. Our current recommendation for nonclearing recurrent postvitrectomy diabetic vitreous hemorrhage is to perform a fluid-air exchange, provided no other high-risk characteristics are present. If clearing occurs in the immediate postexchange period but rebleeding occurs at a later period, we recommend a second fluid-air exchange. If clearing does not occur in the immediate postexchange period, we recommend proceeding directly to revision of vitrectomy.

Adult↗
PubMed1992

Retinal oxygenation and laser treatment in patients with diabetic retinopathy.

The oxygen tension in the preretinal vitreous cavity was measured in human patients undergoing vitreous operations for proliferative diabetic retinopathy. The oxygen tension was significantly higher (P = .004) over areas of retina that had been treated with panretinal photocoagulation than it was over untreated areas in the same retina. This confirmed previous results in animals that showed that panretinal photocoagulation increases the inner retinal oxygen tension. We concluded that panretinal photocoagulation improves the oxygen supply to the inner retina and thereby minimizes the influence of retinal ischemia in diabetic retinopathy.

Blood Pressure↗
PubMed1992

Measurement of preretinal oxygen tension in the vitrectomized human eye using fluorine-19 magnetic resonance spectroscopy.

We obtained oxygen measurements from a human eye that contained small preretinal droplets of perfluorotributylamine (FTBA) by using fluorine-19 magnetic resonance spectroscopy. These droplets were the remainder of a larger volume of FTBA that was used as an intraoperative retinal tamponade during retinal detachment repair. The spin-lattice relaxation rate ([T1]-1) of the FTBA fluorine nuclide was obtained that could then be related, by direct proportionality, to droplet PO2. With the patient in a supine position, the droplets could be positioned over the macula in the preretinal vitreous space, whereon the FTBA PO2 could be influenced by the preretinal oxygen concentration. Preretinal PO2 values, derived from magnetic resonance spectroscopy, were in the range of 6 to 9 mm Hg, although multiple components were identified that were suggestive of a heterogeneous distribution of PO2 values in the population of droplets. To our knowledge, this investigation is the first to demonstrate the feasibility of this approach to performing long-term, noninvasive preretinal oxygen measurements in the vitrectomized human eye by using small droplets of a liquid perfluorochemical.

Adult↗
PubMed1991

The management of retinal detachments associated with choroidal colobomas by vitreous surgery.

We used vitreous surgery to treat seven patients (eight eyes) with complicated retinal detachments associated with choroidal colobomas. All eyes had large choroidal colobomas and no evidence of peripheral retinal breaks. Small, atrophic breaks were detected in five of the eyes and were located in the base of the coloboma in four of the five eyes. Adjunctive surgical techniques were necessary and included cyanoacrylate retinopexy in four eyes, silicone oil tamponade in five eyes, and retinectomy in two eyes. Retinal reattachment was ultimately attained in seven of the eight eyes. The number of surgical procedures ranged from one to five, with an average of three. Postoperative visual acuity of the eyes that underwent anatomically successful procedures ranged from 20/100 to light perception. Proliferative vitreoretinopathy was the most frequent cause of redetachment, occurring in six of the eight eyes.

Adult↗
PubMed1991

Methods, statistical features, and baseline results of a standardized, multicentered ophthalmologic surgical trial: the Silicone Study.

This article describes the trial design and baseline results for the Silicone Study, a multicenter, randomized surgical trial designed to compare the effectiveness of silicone fluid versus long-acting gas in the treatment of proliferative vitreoretinopathy (PVR). Design features include (1) standardization of the surgical protocol to reduce intersurgeon variability, (2) formulation of a PVR clinical classification system relevant to modern vitreoretinal surgery, and (3) creation of a photographic protocol to document PVR pathology. Statistical issues affecting the analysis of the outcome data include (1) the addition of a second group of patients with more severely diseased eyes after the trial began, (2) the change to a different long-acting gas during the course of the trial, and (3) recurrent retinal detachments that require reoperations with the randomized treatment, and, in some instances, a crossover from the randomized to the alternate treatment. Demographic and baseline ocular characteristics are presented for the two groups under study.

Adult↗
PubMed1991

Results of penetrating keratoplasty associated with silicone oil retinal tamponade.

A review of 14 patients who underwent corneal transplantation after intravitreal silicone oil tamponade included an average follow-up of 28 months. Mean graft survival was 25 months (range, 2 to 61 months). Frequency of graft failure was 43% (6 of 14) with a mean occurrence at 14.5 months (range, 2 to 36 months). Allograft rejections occurred in four patients, two of whom progressed to graft failure. The frequency of graft failure was 25% (2 of 8) when silicone oil was removed at the time of keratoplasty compared with 67% (4 of 6) when silicone oil was retained.

Adult↗
PubMed1991

The use of silicone oil in uveitis and hypotony.

Profound hypotony associated with loss of vision complicating bilateral chronic uveitis was managed in five consecutive patients with vitrectomy and silicone oil injection. The use of silicone oil facilitated anatomic reattachment in three of the five eyes, improved visual acuity in all five eyes, and increased or maintained the intraocular pressure (IOP) in four of the five eyes at the 6-month follow-up examination. At the time of the last follow-up examination (mean = 19 months), the IOP was still improved or maintained in four eyes and the visual acuity improved in relation to the baseline in three eyes.

Adult↗
PubMed1990

Cyanoacrylate tissue adhesive in the management of recurrent retinal detachment caused by macular hole.

Nine eyes of nine patients with rhegmatogenous retinal detachment caused by a macular hole were treated by the transvitreal application of cyanoacrylate tissue adhesive to the macular hole. Eight of the nine eyes had previously failed conventional vitreous surgery with gas tamponade and laser photocoagulation. Eight eyes (89%) were completely reattached with a minimum follow-up of three months. In the successfully treated eyes, post-operative visual acuity was 20/200 in two eyes, 20/400 to 5/200 in five eyes, and less than 5/200 in one eye. Direct sealing of macular holes in difficult cases may obviate the need for extended intraocular tamponade or macular buckling with their associated complications.

Aged↗
PubMed1990

Relaxing retinotomies. Analysis of anatomic and visual results.

The authors analyzed 100 consecutive eyes undergoing relaxing retinotomies to determine the anatomic and visual results associated with the use of this procedure. With a minimum follow-up of 6 months, 58 eyes were completely attached, 8 were partially attached (macula on), and 34 were detached. Thirty-four percent of all eyes and 50% of attached eyes obtained a visual acuity of 5/200 or greater at 6 months. At last examination, 29% of all eyes and 43% of attached eyes had a visual acuity of at least 5/200. Eyes that had circumferential relaxing retinotomies involving the entire temporal quadrant generally had lower visual acuities when compared with eyes that had relaxing retinotomies sparing the entire temporal quadrant. The use of a radial relaxing retinotomy also was associated with lower final visual acuity. The length of the relaxing retinotomy or the placement of the relaxing retinotomy either anterior or posterior to the encircling scleral buckle did not appear to influence the anatomic or visual results. Hypotony (intraocular pressure less than 5 mmHg) was seen in 43% of reattached eyes.

Adolescent↗
PubMed1989

Surgical management of retinal traction caused by toxocariasis.

We reviewed the results of vitreous surgery in 12 eyes of 12 patients with tractional macular detachment from Toxocara canis. We performed a vitrectomy and membrane peeling in all eyes, with additional scleral buckling in four eyes. After a minimum of six months' follow-up, ten of the 12 eyes (83%) had complete retinal reattachment. Visual acuity improved in seven eyes, two had no change, and three eyes had decreased visual acuity. Good postoperative vision correlated best with good preoperative vision. Preoperative traction retinal folds through the macula were associated with a poor visual outcome.

Adolescent↗
PubMed1989

Results of silicone oil removal in advanced proliferative vitreoretinopathy.

We reviewed the results of silicone oil removal after vitreous surgery for recurrent retinal detachment with proliferative vitreoretinopathy in 55 eyes. The minimum follow-up period was six months. Retinal detachment recurred in five eyes (9%). Evidence of recurrent epiretinal membrane formation at the time of or after silicone oil removal was noted in 21 eyes (38%). Penetrating keratoplasty combined with silicone oil removal was successful in five of six patients. Mild corneal changes noted in ten eyes (18%) remained the same or cleared in seven eyes after silicone oil removal. Overall, postoperative visual acuity improved in 24 eyes (44%), remained the same in 18 eyes (33%), and decreased in 13 (24%). In 22 eyes without clinical evidence of silicone-associated complications at the time of silicone oil removal, postoperative visual acuity remained unchanged or improved in 20 (91%).

Cornea↗
PubMed1989

Silicone oil injection after failed primary vitreous surgery in severe ocular trauma.

In 42 cases of complicated retinal detachment following trauma after failed primary vitrectomy, at six months follow-up anatomic retinal reattachment posterior to the scleral buckle was achieved in 20 of 40 eyes (50%). Of the 40 eyes, 11 (28%) had a visual acuity of 5/200 or better. Of the eyes that were completely attached posterior to the buckle at six months, 13 of the 20 (65%) remained attached at the last follow-up examination. Many patients who had visual acuities of 5/200 or better at six months experienced a progressive decrease in visual acuity over three years, primarily because of recurrent retinal detachments and corneal edema. A final visual acuity of 5/200 or better was obtained in only five of the 42 eyes (12%) at the last follow-up examination.

Acute Disease↗
PubMed1989

Silicone oil for progressive anterior ocular neovascularization after failed diabetic vitrectomy.

We have performed revision of vitrectomy and silicone oil injection in 18 eyes that developed advanced iris neovascularization and/or anterior hyaloidal fibrovascular proliferation complicated by retinal detachment or media opacity after vitreous surgery for the complications of proliferative diabetic retinopathy. Stabilization or regression of the anterior ocular neovascular changes was noted in 83% of the eyes. Sustained retinal attachment was achieved in 56% of the eyes, with visual acuity improving to 20/400 or better in 28% of the eyes. Posterior segment vascular and avascular reproliferation was the major cause of anatomic failure, while generalized retinal vascular ischemia was felt to be the principal cause of poor visual results despite retinal attachment. Revision of vitrectomy with silicone oil injection is of limited value in the management of complicated and advanced anterior ocular neovascularization after unsuccessful vitrectomy for diabetic retinopathy.

Adult↗
PubMed1989

Temporary iris fixation with a micro-iris retractor.

We developed a new micro-iris retractor to achieve temporary intraoperative pupillary mydriasis in selected eyes undergoing pars plana vitreous surgery. The micro-iris retractor and its use were compared with previous methods for obtaining adequate intraoperative pupillary dilation.

Dilatation↗
PubMed1989

A new retractable micromagnet for intraocular foreign body removal.

We have developed a new, self-contained, small-gauge, permanent, rare-earth magnet for use in conjunction with pars plana vitrectomy in the treatment of selected magnetic intraocular foreign bodies. This magnet allows controlled grasping and releasing of the foreign body by the surgeon, thus increasing surgical control in magnetic intraocular foreign body removal.

Equipment Design↗
PubMed1989

Procoagulant effects of intraocular sodium hyaluronate (Healon) after phakic diabetic vitrectomy. A prospective, randomized study.

A procoagulant effect was reported previously after injection of 0.50 to 0.75 ml of sodium hyaluronate (Healon) into the vitreous cavity at the end of phakic diabetic vitrectomies. A multicenter, randomized, prospective trial was done to study this effect. In the treatment group the media was clear in 50% of eyes in the immediate postoperative period compared with only 8% in the control group. At 2 to 6 weeks, there was no statistically significant difference between the two groups. The authors conclude that such sodium hyaluronate injection provides clear media in a significant number of eyes in the immediate postoperative period, potentially allowing thorough postoperative evaluation and early retinal photocoagulation if needed.

Adult↗