Hussein Wafapoor

The Management of Giant Retinal Tears Using Perfluoroperhydrophenanthrene: A Multicenter Case Series

OBJECTIVE The purpose of the study was to determine the predictors of success and evaluate the use of perfluoroperhydrophenanthrene as an intraoperative and postoperative tool in the management of giant retinal tears in a multicentered collaborative study. DESIGN Multicentered prospective case series. PARTICIPANTS Twenty-three centers consecutively enrolled 162 eyes of 161 patients with retinal tears 90 degrees or greater in circumferential extent. INTERVENTION Perfluoroperhydrophenanthrene was used as an intraoperative surgical adjunct in all cases and left after surgery in 16 eyes (9.9%). MAIN OUTCOME MEASURES Retinal reattachment and visual acuity. RESULTS Intraoperative reattachment was achieved in 158 eyes (97.5%); 147 eyes (90.7%) remained attached at their most recent follow-up. Seventy-nine eyes (48.8%) experienced an improvement in their visual acuity, 26 eyes (16.0%) remained unchanged, and 57 (35.2%) worsened. Recurrent retinal detachment occurred in 80 patients (49.4%). Other significant postoperative complications included cataract formation in 20 (39.2%) of 51 eyes, macular pucker in 12 (7.4%), corneal decompensation in 10 (6.2%), and hypotony (intraocular pressure equal to or less than 5 mmHg) in 9 (5.6%). A chi-square analysis of preoperative characteristics showed that hypotony (P = 0.007), macular detachment (P = 0.020), a history of cataract extraction (P = 0.003), poor visual acuity (P = 0.000), giant tear extent greater than 180 degrees (P = 0.004), and higher grade proliferative vitreoretinopathy (P = 0.000) all predicted a poor visual outcome. Vitreon (Vitrophage, Inc., Lyons, IL) was left in 16 eyes (9.9%) for an extended postoperative retinal tamponade for between 3 and 1034 days (mean, 87.2 days). The Vitreon was well tolerated, and these eyes experienced a similar outcome and rate of retinal reattachment to the rest of the group. CONCLUSIONS Vitreon is a safe and useful adjunct to pars plana vitrectomy in the management of giant retinal tears and may, additionally, be the perfluorocarbon liquid that can be used most safely as a temporary postoperative tool for extended retinal tamponade, reinforcing its role as a useful adjunct in the management of these complex retinal detachments.

SURGICAL MANAGEMENT OF TRAUMATIC RETINAL DETACHMENT WITH PERFLUOROCARBON LIQUID

Background: To evaluate the effect of perfluoroperhydrophenanthrene on the outcome of traumatic retinal detachment with proliferative vitreoretinopathy, a retrospective study of 111 patients was performed at 35 tertiary care centers, both private practice and institutional. We believed that perfluoroperhydrophenanthrene would assist in manipulating the retina during surgery, removing intraocular foreign bodies, draining suprachoroidal hemorrhage, and reattaching the retina because of the perfluorocarbons high specific gravity. Methods: Of the 700 patients in the Vitreon study group, 111 with a history of trauma (109 had retinal detachment, 50 had proliferative vitreo-retinopathy) were chosen for this study. Perfluoroperhydrophenanthrene was used intraoperatively to manipulate the retina hydrokinetically, remove intraocular foreign bodies, drain suprachoroidal hemorrhage, and to reattach the retina in the case of giant tears. Results: Logistic multiple regression analysis was used to identify factors as being predictive of poor visual outcome. Factors predictive of poor visual outcome were: type of trauma (p = 0.0065) (ruptured globe); presence of giant retinal tear (p = 0.0253); and low preoperative visual acuity (p = 0.044). At the last follow-up examination, the reattachment rate was 75.6% (i.e., 84 eyes). Of those 84 eyes, 55 (49.5%) had achieved a visual acuity of ≥ 5/200 and 34 (30.6%) had a visual acuity of ≥ 20/200. In cases complicated by proliferative vitreoretinopathy, the final reattachment rate was 66%, with 40% of the eyes studied obtaining a visual acuity of ≥ 5/200. Conclusions: Perfluoroperhydrophenanthrene has been used intraoperatively in the management of traumatic retinal detachments without any apparent ill effects.

Use of vancomycin in vitrectomy infusion solution and evaluation of retinal toxicity.

The retinal toxicity of vancomycin in infusion solution used in vitrectomy and lensectomy was investigated in rabbit eyes by means of electroretinography and histologie study (light microscopy). Concentrations of 8μg/ ml, 16μg/ml, and 32μg/ml of vancomycin in balanced salt solution caused no abnormal ERG or histologic changes. However, ERG amplitude depression and abnormal histologie changes occurred when the concentration of 100μg/ml of vancomycin was used.

Experimental retinal tolerance to very low viscosity silicone oil (100 cs) as a vitreous substitute compared to higher viscosity silicone oil (5000 cs)

We evaluated the toxicity of very low viscosity (100 centistokes) and higher viscosity silicone oil (5000 centistokes) in rabbit eyes as a short-to-long-term postoperative vitreous substitute (6 weeks to 5 months). Emulsification of 100-cs and 5000-cs silicone oil did not occur in eyes which were followed for as long as 5 months. No toxic effects to retinal cells were detected by light or electron microscopy. Because no toxic effects were seen with 100-cs silicone oil, it can be used in an outpatient setting as a short-term postoperative tamponading agent. Electroretinographic responses of silicone-injected eyes were normal.

Surgical closure of macular hole using an absorbable macular plug

Background: The surgical management of macular holes has been a subject of controversy in recent years. Various techniques such as vitrectomy, membrane peeling, and gas tamponade with or without transforming growth factor-beta 2, and recently the use of autologous platelets have produced closure rates from 58% to 96%, depending on the stage of the hole. Methods: The authors present preliminary results in a study of 19 consecutive patients with stage 3 or stage 4 macular hole who underwent vitrectomy followed by placement of an absorbable partially cross-linked gelatin plug in the macular hole. The vitreous cavity was filled with a nonexpanding gas or air alone; the patient was instructed to maintain prone positioning for 2–3 days. Results: Anatomic attachment of the edges of the macular hole was achieved in 19 out of 19 patients with a minimum follow-up period of 6 months (average 11.5 months). Conclusions: A cross-linked gelatin plug can effectively reattach the edges of macular holes of stages 3 and 4. Its use is recommended only in macular holes in high myopes with posterior staphyloma or recurrent macular hole.

An Analysis of Posterior Segment Complications After Vitrectomy Using the Perfluorocarbon Perfluoroperhydrophenanthrene (Vitreon)

We report posterior segment complications encountered with the use of the liquid perfluorocarbon, perfluoroperhydrophenanthrene (Vitreon) as an intraoperative adjunct to vitreoretinal surgery in 640 patients participating in the Vitreon Collaborative Study. We also evaluated postoperative complications in 60 patients in whom Viteron was intentionally left inside the vitreous cavity for periods ranging from 5 days to 4 weeks as a short-term retinal tamponade. The five most common postoperative complications among these patients as a whole were recurrent retinal detachment, with or without proliferative vitreoretinopathy (11.28%); macular pucker (5.85%); fibrinous reaction (4%); residual Vitreon (3.85%); and vitreous hemorrhage (2.57%).

Postoperative Chronic Pressure Abnormalities in the Vitreon Study

Perfluoroperhydrophenanthrene (Vitreon) was used as an intraoperative hydrokinetic retinal manipulator, followed by C3F8 or SF6 gases, silicone oil, or Vitreon as postoperative tamponading agents in 234 eyes. Two chronic intraoperative pressure abnormalities were defined: hypotony (5 mm Hg or less) and elevated intraocular pressure (IOP) (25 mm Hg or more at three or more postoperative visits). Postoperatively, 28 eyes (12%) had chronically elevated IOP, and 41 (18%) had chronic hypotony. There was no significant difference in the incidence of abnormal IOP among the groups of eyes in which the various tamponading agents had been used. In particular, the use of Vitreon as an intraoperative tool or as a short-term tamponade did not affect the incidence of chronic abnormal IOP any more than did the use of silicone oil, C3F8, or SF6 as tamponading agents.

Assessment of Novel Guarded Needle to Increase Patient Comfort and Decrease Injection Time During Intravitreal Injection

BACKGROUND AND OBJECTIVE To determine whether a novel guarded 33-gauge injection device can make the intravitreal injection procedure faster and more comfortable for patients. PATIENTS AND METHODS Single-center, prospective, randomized interventional study. Seventy participants receiving bilateral injections on the same day had one eye injected with the 33-gauge injection device without a speculum and the other eye injected with a standard 30-gauge needle using a speculum. Length of time needed for the injection procedure was assessed, and subjects were asked to complete a questionnaire regarding their comfort level with each device during the injection procedure as well as immediately after, later that evening, and the next day. RESULTS Intravitreal injections using the 33-gauge injection device were significantly faster, but there was no significant difference in the incidence or levels of pain between the two needle types. CONCLUSION The 33-gauge injection device may offer advantages over a standard 30-gauge needle when performing an intravitreal injection.

Hyperbaric oxygne tolerance in newborn mammals-hypothesis on mechanisms and outcome

Newborn mammals, compared to adults, are extremely resistant to the CNS effects of hyperbaric oxygenation (HBO) induced by excessive generation of reactive oxygen species. This tolerance to HBO may be related to either physiological responses or the chemical characteristics of the immature brain, including a low cerebral blood flow and energy metabolism, and a low concentration of polyunsaturated fatty acids. In adult mammals the main protective mechanism against CNS oxygen toxicity, besides endogenous antioxidants, is a transient HBO-induced cerebral vasoconstriction. How cerebral vasculature reacts to HBO in the immature brain is not known. We present indirect evidence suggesting that HBO in newborn rats induces a persistent cerebral vasoconstriction concurrently with a severe and maintained reduction in ventilation. It is speculated that the outcome of these physiologic responses to hyperoxic exposures may be: (a) extension of tolerance to both CNS and pulmonary oxygen poisoning; (b) creation of a profound hypoxic-ischemic condition in vulnerable neural structures; and (c) impairment of the circulatory and ventilatory responses to hypoxic stimuli on return to air with consequent development of a secondary hypoxic-ischemic condition. These hypothetical pre- and post-HBO events may set the stage for the development of some delayed neurological disorders, including the retinopathy of prematurity and the retardation of brain development in fetuses or prematurely-born infants subjected to oxygen therapy.

Injection force comparison of the old and new dexamethasone implant insertion needles in porcine eyes and synthetic sclera.

BACKGROUND AND OBJECTIVE Determine whether the new dexamethasone intravitreal implant (Ozurdex; Allergan, Irvine, CA) injector needle design can reduce the force needed for insertion when compared to the original needle design. MATERIALS AND METHODS In vitro testing assessed the force required for insertion from five new-design and five old-design Ozurdex needles on a synthetic test medium and explanted porcine eyes. Maximum penetration force was measured in grams-force, while the total work of the needle was measured in joules. RESULTS The new design required 29% and 68% less overall work to perform an injection in the synthetic medium (P = .0002) and porcine eyes (P = .009), respectively. The maximum force required to insert the new needle was 25% and 61% that of the old needle in the synthetic medium (P = .001) and porcine eyes (P = .007), respectively. CONCLUSION The new needle design significantly reduces the force and work needed for insertion, which should improve physician control as well as patient safety and comfort.