Current management of diabetic tractional retinal detachments.

Twenty-five percent of diabetes-related vision loss stems from complications of proliferative diabetic retinopathy (PDR). Panretinal photocoagulation has been the preferred treatment of high-risk PDR for decades and more recently intravitreal injections of drugs that inhibit the actions of vascular endothelial growth factor have become popular. But despite these treatments PDR may progress uncontrollably to advanced pathologies such as traction retinal detachments (TRDs), combined traction/rhegmatogenous retinal detachments (TRD/RRDs), vitreous hemorrhages, rubeosis iridis, and traction maculopathies, which produce mild-to-severe loss of vision. TDR have long been the most common indication for PDR-related vitreoretinal surgery. Vitrectomy surgery is indicated for recent (<6 months duration) TRD involving the macula, progressive TRD that threatens the macula, and recent data suggest that chronic macula-involving TRDs (>6 months duration) may also benefit. Combined TRD/RRD represents a particularly challenging surgical condition but advances in surgical instrumentation, dissection techniques, and post-operative tamponade have produced excellent success rates. The recent development of small-gauge vitrectomy systems has persuaded most surgeons to switch platforms since these appear to produce shorter surgical times and quicker post-operative recoveries. Pre-operative injections of bevacizumab are frequently administered for persistent neovascularization to facilitate surgical dissection of pre-retinal fibrosis and reduce the incidence of post-operative hemorrhages. Recent trends toward earlier surgical intervention and expanded indications are likely to continue as surgical instrumentation and techniques are further developed.

Vitrectomy in the management of diabetic macular edema in treatment-naïve patients.

OBJECTIVE: To determine the efficacy of vitrectomy in eyes with treatment-naïve diabetic macular edema (DME). METHODS: Consecutive patients with treatment-naïve DME who underwent pars plana vitrectomy with internal limiting membrane peeling at a single institution were identified from the electronic medical records. Morphologic and visual acuity changes from baseline were analyzed at both the primary temporal endpoint (6 months) and the final examination with the investigators. The primary outcome measures included changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT). RESULTS: Forty-four eyes of 44 patients were included in this retrospective study. The mean BCVA improved significantly from baseline until the 6-month primary endpoint (1.35 logMAR vs 0.83 logMAR, p < 0.001) and stabilized through the final examination (0.77 logMAR). The BCVA improved by at least 0.1, 0.3, and 0.6 logMAR in 26 (60%), 24 (55%), and 14 (32%) of eyes, respectively, whereas it worsened by 0.3 logMAR in only 1 (2%) eye. Final BCVA correlated inversely with duration of diabetes (p = 0.01), presence of an epiretinal membrane (p = 0.02), and initial visual acuity (p = 0.03). Mean CRT decreased significantly from baseline through 6 months (595 µm vs 266 µm; p < 0.001), and edema recurred in only 3 eyes (6%), one of which was subsequently treated with intravitreal bevacizumab. CONCLUSIONS: Pars plana vitrectomy significantly improves macular edema and visual acuity in eyes with treatment-naïve DME. Prospective randomized trials are needed to better determine the efficacy of early vitrectomy.

Vitrectomy for center-involved diabetic macular edema.

PURPOSE: To determine the effect of vitrectomy for center-involved diabetic macular edema (CI-DME). METHODS: This was a retrospective study of 53 eyes of 45 patients who had vitrectomy for CI-DME and were followed up for at least 12 months. Charts were reviewed for visual acuity (VA), central subfield mean thickness measured by optical coherence tomography, presurgical and postsurgical interventions for CI-DME, and number of office visits in the first 12 months after surgery. Preoperative spectral domain optical coherence tomography was performed on 38 patients, and they were graded for ellipsoid zone (EZ) intactness by three independent graders with assessment of agreement between graders using intraclass correlation coefficients and Bland-Altman analysis. RESULTS: The median VA improved from 20/100 (interquartile range [IQR], 20/63-20/200) at baseline to 20/63 (IQR, 20/32-20/125) at 12 months. The median central subfield mean thickness improved from 505 µm (IQR, 389-597 µm) at baseline to 279 µm (IQR, 246-339 µm) at 12 months. Intergrader agreement for EZ intactness was moderate (intraclass correlation coefficients 0.4294-0.6356). There was no relationship between preoperative intactness of the EZ and the 12-month change in VA. CONCLUSION: Vitrectomy consistently thins the macula in CI-DME and, on average, leads to clinically significant improvement in VA comparable in size to that reported with serial intravitreal anti-vascular endothelial growth factor injections. A large, comparative, prospective, randomized clinical trial of these two treatments is needed to determine which is more effective and cost-effective.

Vitreous humor thermodynamics during phacoemulsification.

The purpose of this study is to determine baseline vitreous humor temperature during a combined phacoemulsification and pars plana vitrectomy (PPV) procedure; to determine what is the temperature variation during phacoemulsification; and to compare vitreous temperature to sublingual temperature. The methods used are prospective, interventional and comparative study. Patients with a diagnosis of cataract and vitreous hemorrhage, programed for a combined procedure of phacoemulsification and PPV, were included. Patients were excluded if posterior capsular rupture existed during the anterior segment procedure. A thermoprobe was inserted through a PPV trocar. Measurement of the vitreous temperature was obtained at baseline and throughout phacoemulsification, at the end of every surgical step, and every 5 min. Sublingual temperature was measured with the same probe at the end of the surgery. Room temperature was registered. Seventeen eyes of 17 patients were included. Mean sublingual temperature was 36.5 °C (standard deviation [σ] 0.26 °C). Mean total vitreous temperature was 31.47 °C (σ 2.1 °C). Mean baseline vitreous temperature was 33.04 °C (σ 0.99 °C). Comparison of sublingual temperature with baseline vitreous temperature resulted in a significant difference (t test P < 0.000. 95 % confidence interval 2.93-3.98). Temperature measured by surgical step and surgical time presented a significant decrease in temperature from baseline (Kruskal-Wallis P < 0.000, P = 0.003, respectively). Vitreous humor is significantly hypothermic when compared to sublingual temperature. Vitreous temperature decreases significantly during phacoemulsification.

Immediate hyphema after intravitreal injections of ranibizumab.

PURPOSE: To report two cases of immediate hyphema formation after the intravitreal injection of ranibizumab. METHODS: Retrospective case reports. RESULTS: A patient with choroidal neovascularization caused by exudative age-related macular degeneration and a patient with cystoid macular edema caused by branch retinal vein occlusion underwent an intravitreal injection of 0.5 mg/0.05 mL of ranibizumab. The development of hyphema was seen immediately after the intravitreal injection in both cases. One patient was pseudophakic, taking 325 mg of aspirin daily. The other patient was phakic without any anticoagulation history. CONCLUSION: To the best of our knowledge, this is the third report of the development of hyphema associated with intravitreal injections.

Determination of retinal and vitreous temperature in vitrectomy.

PURPOSE/BACKGROUND: To maximize recovery after neurologic injury, physicians use therapeutic hypothermia of 90°F to 93°F (32.2-33.9°C). Temperatures below this are avoided because of increased side effects. The extent to which the retina is cooled during routine vitreous surgery is unknown. This study seeks to describe the temperature changes of the vitreous and retinal surface during vitreous surgery. METHODS: In this prospective study of 6 patients undergoing vitrectomy, a 23-gauge thermoprobe was used to measure intraocular temperatures before, during, and after vitrectomy. RESULTS: Before vitrectomy, the mean midvitreous temperature was 93.1°F (33.9°C) and retinal temperature was 94.7°F to 95.4°F (34.8-35.2°C). During vitrectomy, the mean midvitreous cavity temperature was 76.9°F (24.9°C) and retinal temperature was 83.2°F to 85.1°F (28.4-29.5°C). After completion of vitrectomy and with a closed infusion line, the mean midvitreous cavity temperature was 87.0°F (30.6°C) and retinal temperature was 90.1°F to 90.9°F (32.3-32.7°C). These changes in temperature before, during, and after vitrectomy were found to be statistically significant. CONCLUSION: During routine vitreous surgery, the vitreous cavity and retina are cooled to much lower temperatures than those used in therapeutic hypothermia. Rapid rewarming occurs within the eye once the infusion line is closed.

The landers trunkless temporary keratoprosthesis.

OBJECTIVE: To demonstrate the watertight seal created by the new wide-angle Landers trunkless temporary keratoprosthesis (T-TKP). METHODS: In 20 enucleated, porcine eyes, a 7.5-mm trephination was made, followed by capsulorrhexis and lensectomy. The T-TKP was sutured securely onto each eye. Testing the watertight seal at an intraocular pressure of 100 mm Hg was performed before and after pars plana vitrectomy. RESULTS: In all 20 eyes, the T-TKP maintained its watertight seal at an intraocular pressure of 100 mm Hg before and after vitrectomy. CONCLUSION: The Landers T-TKP is a reusable device that provides a clear view and watertight eye in the presence of corneal trephinations up to 7.5 mm in diameter. Because of its unique trunkless design, as demonstrated in the laboratory, the T-TKP should allow the surgeon greater flexibility than previous models in cases of ocular trauma.

Maintaining a watertight globe while operating with a temporary keratoprosthesis.

PURPOSE: To demonstrate that the Landers wide-field temporary keratoprosthesis (TKP) creates a watertight seal between the tightly opposing surfaces of the TKP flange and the anterior corneal surface. METHODS: In 25 and 20 enucleated, porcine eyes, a 7.5-mm and 8.0-mm trephination corneal hole was made, respectively, followed by open-sky capsulorhexis and lensectomy. A wide-field TKP with 7.2 mm trunk diameter was sutured securely onto each eye. Testing for a watertight seal was performed at an intraocular pressure of 100 mmHg of pre- and post-pars plana vitrectomy. RESULTS: The Landers TKP maintained a watertight seal at an intraocular pressure of 100 mmHg in 45 of 45 eyes. After standard pars plana vitrectomy, 41 of 41 eyes maintained 100 mmHg of intraocular pressure without leakage. CONCLUSION: The seal between the TKP and cornea is established at the horizontal interface between the TKP flange and the anterior corneal surface, not between the corneal stroma and TKP trunk. The Landers wide-field TKP is a reusable model that provides a clear posterior-segment view and effectively forms a watertight eye at a sustained intraocular pressure of 100 mmHg. This TKP may be used in ocular trauma where the corneal defect is up to 0.8 mm greater in diameter than the 7.2-mm TKP trunk.

The effect of unilateral intravitreal bevacizumab (avastin), in the treatment of diffuse bilateral diabetic macular edema: a pilot study.

PURPOSE: To investigate whether there are systemic effects of unilateral intravitreal administration of bevacizumab on the untreated eye. METHODS: Twenty-three consecutive patients were enrolled in this study. All patients had a clinical diagnosis of bilateral diffuse diabetic macular edema with a central retinal thickness greater than 275 microm by Optical Coherence Tomography. They were treated with 2.5 mg bevacizumab intravitreally in the worst eye based on lines of vision, number of Early Treatment Diabetic Retinopathy Study letters, and central retinal thickness. The patients were observed every 2 weeks for 4 weeks. The Best Corrected Visual Acuity, central retinal thickness (microm), and macular volume (mm) in the untreated eye measured by Optical Coherence Tomography were recorded at every visit. RESULTS: The Best Corrected Visual Acuity (mean +/- SD) in the untreated eye was 34.46 +/- 17.29. Early Treatment Diabetic Retinopathy Study letters at baseline, 38.31 +/- 14.64 at 2 weeks, and 37.38 +/- 14.59 at 4 weeks. The central retinal thickness in the untreated eye was 324.77 +/- 76.51 microm at baseline, 319 +/- 75.7 microm at 2 weeks, and 315.54 +/- 78.2 microm at 4 weeks. The macular volume in the untreated eye was 8.99 +/- 1.2 mm at baseline, 9.16 +/- 1.26 mm at 2 weeks, and 8.99 +/- 1.09 mm at 4 weeks. There were no statistically significant differences between any of the measurements. CONCLUSION: Due to the lack of significant changes in the measurements of the untreated eye, the systemic effect of intravitreal bevacizumab seems to be unlikely. The small sample and low confidence of this pilot study prevent us to draw concrete conclusions.

Transscleral intraocular lens fixation with a "homemade" needle and hook.

We describe an ab externo, transscleral, intraocular lens (IOL) fixation technique using a surgeon-fashioned 25-gauge hook, a neodymium:yttrium aluminum garnet (Nd:YAG)-modified 27-gauge needle, and 9-0 polypropylene suture. This is a simple, inexpensive technique for creating small-gauge surgical instruments to accurately and atraumatically pass 9-0 and 10-0 polypropylene sutures through sclera. Holes, through which sutures can be threaded, are "burned" near the tips of 27-gauge or 30-gauge needles with an Nd:YAG laser. Using a fine needle holder, a 25-gauge hook is fashioned from a hypodermic needle. A surgical technique incorporating 2 ab externo incisions and achieving transscleral posterior chamber IOL fixation is discussed.

Management of post-vitrectomy persistent vitreous hemorrhage in pseudophakic eyes.

PURPOSE: To prospectively assess the effect of neodymium:yttrium-aluminum-garnet peripheral capsulotomy on postvitrectomy hemorrhage in diabetic patients with a posterior chamber intraocular lens (IOL) implant and an intact posterior capsule. DESIGN: Interventional case series. METHODS: This is a prospective case series, clinical practice. PATIENTS: Five vitrectomized, diabetic, pseudophakic patients with persistent vitreous cavity hemorrhage remaining after vitrectomy were selected. They all had a posterior chamber IOL implant with an intact posterior capsule. Additionally, they had all undergone laser panretinal photocoagulation in the involved eye in the past for diabetic retinopathy. Neodymium:yttrium-aluminum-garnet laser capsulotomy outside the optic of the IOL was performed in victrectomized diabetic patients to treat the remaining vitreous cavity hemorrhage. Visual acuity, intraocular pressure (IOP), and fundus examination were measured and done immediately after the laser procedure, in 7 days and in approximately 3 months. RESULTS: The visual acuity was improved at the time of the first follow-up. However, a mild elevation of IOP was noticed in some patients, which was treated with topical dorzolamide. The final visual acuity was dramatically improved, to 20/30 or better, and the IOP was normalized without medication within a few weeks in all five cases. No neovascularization of the iris or elsewhere was noticed in any case. CONCLUSIONS: Neodymium:yttrium-aluminum-garnet laser peripheral capsulotomy appears to be a safe and effective management procedure in treating postvitrectomy hemorrhage in diabetic patients who have previously undergone cataract surgery with posterior chamber lens implant, intact posterior capsule, and extensive panretinal photocoagulation. The vitreous hemorrhage cleared completely in all five cases.

A new, non-contact wide field viewing system for vitreous surgery.

PURPOSE: To report a new, noncontact wide field viewing system for vitreoretinal surgery. DESIGN: Device description: A noncontact wide field viewing system consisting of adjustable hinged arm and a combined condensing lens and reinverting prism has been developed. The arm clamps onto the operating table or wrist rest and holds the lens system in the air above the eye. METHODS: For vitreoretinal surgery, a new, relatively inexpensive noncontact wide field viewing system consisting of an adjustable hinged arm and a combined condensing lens and reinverting prism has been developed. The combination condensing lens and reinverting prism is used without a microscope-mounted inverter. The optical component may be sterilized with ethylene oxide, peracetic acid, or glutaraldehyde. Other components may be steam autoclaved. RESULTS: The new, noncontact wide field viewing system has been used satisfactorily in more than 200 vitrectomies at seven medical centers. It provides an excellent view of the vitreous and retina. CONCLUSION: A new, noncontact wide field viewing system for vitreoretinal surgery has been developed with satisfactory image quality and a field of view comparable to contemporary noncontact panoramic viewing systems.

Computer-automated quantification of plus disease in retinopathy of prematurity.

BACKGROUND: In some cases of retinopathy of prematurity (ROP), it difficult to determine with certainty whether plus disease is present or absent. We have developed a computer program that captures digital images from a video-indirect ophthalmoscope, identifies and traces the major posterior pole blood vessels, measures the dilation and tortuosity of each vessel, and calculates whether or not an eye has plus disease. Our purpose was to determine the accuracy of the computer program in comparison with two masked examiners. METHODS: A representative sample of posterior pole images from 20 premature infants, 10 normal and 10 representing various degrees of dilation and tortuosity, was extracted from our video database and analyzed by the computer program as well as by two masked examiners experienced in the diagnosis of ROP. The standard photograph from the Cryotherapy for ROP study, representing the minimum degree of dilation and tortuosity required for plus disease, was also digitized, analyzed, and used as a numeric comparison for the automated determination of plus disease. RESULTS: Of the five images determined to have plus disease by both examiners, four were calculated to have plus disease by the computer program (80% sensitivity). Of the 11 images without plus disease, 10 were calculated not to have plus disease by the computer program (91% specificity). CONCLUSIONS: Our computer program has very good sensitivity and specificity compared with masked examiners' determination of the presence or absence of plus disease. Automated analysis of dilation and tortuosity of posterior pole blood vessels has the potential to remove subjectivity from the determination of plus disease.