Masahito Ohji

A 27–Gauge Instrument System for Transconjunctival Sutureless Microincision Vitrectomy Surgery

OBJECTIVES To evaluate the efficiency, preliminary safety, and feasibility of a 27-gauge instrument system for transconjunctival microincision vitrectomy surgery (MIVS) in a variety of vitreoretinal diseases. DESIGN Experimental, interventional case series. PARTICIPANTS Thirty-one eyes (31 patients) underwent a variety of vitreoretinal procedures using the 27-gauge transconjunctival MIVS system to treat epiretinal membrane (n = 10), idiopathic macular holes (n = 7), diabetic vitreous hemorrhage (n = 5), vitreous opacity with suspicion of intraocular lymphoma (n = 4), focal diabetic traction retinal detachment (n = 3), macular traction syndrome (n = 1), and macular edema secondary to central retinal vein occlusion (n = 1). METHODS We developed a 27-gauge instrument system that includes an infusion line, a high-speed vitreous cutter, an illumination system, and a variety of vitreoretinal instruments, such as membrane forceps and sharp-tipped endophotocoagulation probes. The duty cycle of the 27- and 25-gauge cutters was measured for several cut rates using a high-speed imaging camera. Infusion and aspiration rates were measured using balanced saline solution (BSS) and porcine vitreous with different aspiration levels. Surgical outcomes, including anatomic success, visual outcomes, operating times, and intraoperative and postoperative complications, were evaluated. MAIN OUTCOME MEASURES Duty cycle of cutters, infusion and aspiration rates, and surgical results of 27-gauge vitrectomy. RESULTS Although the infusion and aspiration rates of the 27-gauge system measured in BSS were reduced to an average of 62% and 80%, respectively, compared with those of the 25-gauge system, the duty cycle of the 27-gauge cutter, 61% at 1000 cpm and 38% at 1500 cpm, was equal to or better than those of the 25-gauge cutter (62% and 28%, respectively). Analysis of the fluid dynamics showed that vented gas-forced infusion can be set to range from 20 to 30 mmHg to control intraocular pressure (IOP) during 27-gauge vitrectomy. Anatomic success was achieved in all study eyes (100%); 20 eyes (65%) had visual improvement of 3 lines or more. No eyes required conversion to larger gauge instrument. All sclerotomies self-sealed without hypotony (IOP < or = 7 mmHg) from 1 day postoperatively. CONCLUSIONS Although the fluid dynamics and cutting efficiency of 27-gauge instruments are lower compared with 25-gauge MIVS, the 27-gauge system is feasible and may reduce concerns about wound sealing-related complications in selected cases. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Microincision Vitrectomy Surgery and Intravitreal Bevacizumab as a Surgical Adjunct to Treat Diabetic Traction Retinal Detachment

PURPOSE To investigate the feasibility and efficacy of microincision vitrectomy surgery (MIVS) combined with intravitreal bevacizumab (IVB) as a surgical adjunct for treating traction retinal detachment (TRD) secondary to severe proliferative diabetic retinopathy (PDR). DESIGN Retrospective, comparative, consecutive, interventional case series. PARTICIPANTS Seventy-one eyes of 59 consecutive patients who underwent primary vitrectomy for diabetic TRD and were followed up for more than 6 months after surgery. METHODS Eyes that received IVB (1 mg) as a preoperative adjunct followed by MIVS (IVB/MIVS group) from November 2005 through December 2007 were compared with eyes that underwent conventional 20-gauge pars plana vitrectomy (20-g PPV group) from September 2003 through October 2005. MAIN OUTCOME MEASURES Primary and ultimate anatomic success, intraoperative and postoperative complications, and final visual success with at least 6 months of follow-up. RESULTS This series included 38 eyes (33 patients) in the IVB/MIVS group and 33 eyes (26 patients) in the 20-g PPV group. The primary and ultimate anatomic success rates (95% vs. 91% and 100% in both groups, respectively) and the mean visual acuity changes did not differ significantly between groups; the surgical time and intraoperative bleeding in the IVB/MIVS group decreased significantly compared with the 20-g PPV group (P<0.001). The rate of visual improvement of 3 lines or more at the 6-month follow-up was 68% in the IVB/MIVS group and 49% in the 20-g PPV group, respectively. Progression of the preexisting TRD after IVB occurred in 7 eyes (18%). Absence of previous laser photocoagulation (P = 0.025) and the presence of a ring-shaped fibrovascular membrane (P = 0.013) were relevant findings in eyes with these IVB-induced complications. CONCLUSIONS Intravitreal bevacizumab plus MIVS offers comparable anatomic success compared with conventional 20-gauge PPV in patients with TRD resulting from severe PDR. This technique shortens the surgical time with fewer intraoperative complications and favorable visual recovery. However, caution should be taken because of rapid progression of the preexisting TRD after IVB in some patients. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Optical coherence tomographic findings of Macular holes and retinal detachment after vitrectomy in highly myopic eyes

PURPOSE Macular holes cause retinal detachments in highly myopic eyes. Because degenerative macular changes often coexist, biomicroscopic evaluation of macular hole status after retinal reattachment is sometimes difficult. We studied macular holes with retinal detachment after vitrectomy using optical coherence tomography and evaluated the anatomic status of the hole and factors associated with anatomic success. DESIGN Retrospective, nonrandomized, comparative study. PATIENTS Sixteen eyes that underwent vitrectomy for retinal detachment associated with a macular hole were included. Internal limiting membrane peeling with indocyanine green was performed in 14 eyes; the epiretinal membrane was peeled with a diamond-dusted membrane scraper alone in two eyes. All retinas reattached postoperatively. The follow-up period at the optical coherence tomography examination was at least 6 months. METHODS Optical coherence tomography was performed vertically and horizontally, and the presence of a persistent macular hole was determined. Other information was obtained from patient records. RESULTS The macular holes closed in seven of 16 eyes (44%). Age, sex, axial length, preoperative best-corrected visual acuity, duration of symptoms, preoperative refractive error, and the preoperative area of the retinal detachment were not significantly correlated with hole closure. Improved postoperative best-corrected visual acuity (P <.05) was significantly associated with macular hole closure, and more frequent visual improvement (P =.06) was of borderline significance. CONCLUSIONS The success rate was lower than those obtained in eyes without myopia or in myopic macular holes without retinal detachments. Macular hole closure may predict improved visual outcome for patients with retinal detachment and macular holes. Optical coherence tomography detects persistent macular holes in highly myopic eyes with retinal detachment.

Pharmacokinetics of bevacizumab and its effect on vascular endothelial growth factor after intravitreal injection of bevacizumab in macaque eyes.

PURPOSE To evaluate the pharmacokinetics of intravitreally injected bevacizumab in the systemic circulation and the aqueous humor and its effect on vascular endothelial growth factor (VEGF) in the aqueous humor. METHODS Bevacizumab (1.25 mg/50 microL) was injected into the vitreous cavity of the right eyes of three cynomolgus macaques. Aqueous humor and serum were obtained from the macaques just before injection and on days 1, 3, and 7 and weeks 2, 4, 6, and 8 after injection. The bevacizumab and VEGF concentrations were measured using enzyme-linked immunosorbent assay. RESULTS Aqueous VEGF concentrations ranged from 63.2 to 106 pg/mL (mean, 80.0 +/- 22.6 pg/mL) before injection; decreased to <31.2 pg/mL, the lower limit of detection, in all eyes between 1 and 28 days after injection; and returned to the preinjection concentration at 42 days. Aqueous VEGF concentrations in the fellow eyes did not change throughout the experiment. Aqueous bevacizumab concentrations in the treated eyes reached a mean peak concentration of 49,500 +/- 10,900 ng/mL the day after injection and gradually declined, whereas those in the untreated eyes peaked at 3 days, with a mean concentration of 18.5 +/- 25.5 ng/mL, and declined to below 0.156 ng/mL, the limit of detection at 2 weeks. A maximum mean bevacizumab concentration of 1430 +/- 186 ng/mL was achieved in the serum 1 week after injection. CONCLUSIONS Intravitreal injection of bevacizumab decreased the VEGF concentration in the treated eyes for at least 4 weeks and had no or a minimal effect on the untreated fellow eyes.

Comparison of macular thickness between Cirrus HD-OCT and Stratus OCT.

BACKGROUND AND OBJECTIVE To compare macular thicknesses in healthy subjects measured with spectral domain optical coherence tomography (SD-OCT) (Cirrus; Carl Zeiss Meditec, Inc., Dublin, CA) with measurements using time domain (TD-OCT) (Stratus; Carl Zeiss Meditec, Inc.). PATIENTS AND METHODS Macular thickness was measured five times in the same eye of 10 healthy subjects with both Cirrus and Stratus to assess reliability and then once in the same eye of 50 healthy subjects with both Cirrus and Stratus to compare the average obtained by each device. RESULTS Using TD-OCT, the coefficient of variations (CV) of the macular thicknesses within a 1-mm central area ranged from 0.7% to 3.3% (mean, 1.33%); with SD-OCT, the range was 0.2% to 1.3% (mean, 0.66%). The mean CV with SD-OCT was significantly smaller than with TD-OCT (P < .05). The average macular thicknesses with TD-OCT and SD-OCT were 197.2 +/- 17.8 microm and 257.6 +/- 19.6 microm, respectively. However, the correlation was significant (correlation coefficient, 0.916, P<.001). CONCLUSION Cirrus showed better reliability than Stratus. Using SD-OCT, the macula was 60-microm thicker than when measured with TD-OCT. Attention should be given to comparing data obtained using different OCT machines.

Transretinal Electrical Stimulation with a Suprachoroidal Multichannel Electrode in Rabbit Eyes

PurposeSeveral approaches for placing an electrode device for visual prosthesis have been previously proposed. In this study, we investigated if transretinal stimulation from the suprachoroidal space can elicit an electrical evoked potential (EEP) in albino rabbits.MethodsA flat electrode array (polyimide plate, platinum electrode) was developed and used for this study. After performing a scleral incision at 2–2.5 mm from the limbus and placing an anchoring suture, the array was inserted into the suprachoroidal space in the posterior portion of the eye by direct observation under a microscope. A platinum wire was implanted into the vitreous space as a reference electrode. For electrical stimulation, a biphasic pulse was used. When the electrode was stimulated, the EEP was recorded.ResultsWhen the electrical stimulation from the suprachoroidal space was applied, the EEP could be recorded with an epidural electrode, and the threshold was 66.0 ± 32.1μA (42.0μC/cm2). Histological examination indicated the absence of major damage to the retina and choroid from the insertion and placement of the array and the electrical stimulation.ConclusionsTransretinal electrical stimulation from the suprachoroidal space could elicit EEP, suggesting that this approach may be useful for a retinal prosthesis system.

Choroidal neovascularisation in pathological myopia: an update in management

Choroidal neovascularisation (CNV) secondary to pathological myopia is an important cause of significant visual impairment in young and middle aged adults globally and is particularly prevalent in Asian populations. In the past few years, there have been rapid advancements in the different treatments for myopic CNV. The purpose of this perspective is to give an overview of the natural history of myopic CNV and the various treatment options including laser photocoagulation, photodynamic therapy, submacular surgery, and macular translocation surgery. Future directions in the management of myopic CNV are also discussed.

Visual function after foveal translocation with scleral shortening in patients with myopic neovascular maculopathy.

PURPOSE To document the visual outcome after successful foveal translocation with intentional retinal detachment and scleral shortening for the treatment of myopic neovascular maculopathy. METHODS Two severely myopic patients with subfoveal neovascular membranes underwent surgical translocation of the fovea to an area of healthy retinal pigment epithelium by means of scleral shortening and intentional retinal detachment. In the postoperative period, monocular and binocular visual function were studied. RESULTS In one patient, best-corrected visual acuity improved from 20/150 to 20/20 postoperatively. In the second patient, acuity initially improved from 20/70 to 20/30. In both patients, the fixation point shifted from the site of the neovascular membrane. Oblique astigmatism developed and was managed with hard contact lenses. Diplopia and subjective torsion occurred transiently. Micropsia occurred in one patient. Peripheral fusion assessed by Worth four-dot testing after resolution of diplopia disclosed suppression in the nondominant eye in both cases. CONCLUSIONS Foveal translocation with intentional retinal detachment and scleral shortening was useful in improving visual acuity in two patients with myopic neovascular maculopathy. Diplopia and aniseikonia occurred but resolved over time as suppression developed. This technique is promising for patients with myopic neovascular maculopathy.

Marked Intraocular Pressure Response to Instillation of Corticosteroids in Children

We examined intraocular pressures of patients with strabismus whose eyes were instilled with corticosteroid eyedrops after a strabismus operation. Group A consisted of 11 children under 10 years of age whose eyes were instilled with 0.1% dexamethasone; Group B consisted of nine patients 10 years old or older whose eyes were instilled with 0.1% dexamethasone; and Group C consisted of 13 children under 10 years of age whose eyes were instilled with 0.1% fluorometholone. In Group A, four patients had intraocular pressures greater than 30 mm Hg, five had intraocular pressures from 21 to 30 mm Hg, and two had intraocular pressures under 21 mm Hg one or two weeks postoperatively. The intraocular pressure decreased to less than 21 mm Hg one week after discontinuation of dexamethasone treatment in all nine patients. No patients in Groups B or C had intraocular pressures greater than 20 mm Hg. Our results suggest that marked ocular hypertensive response to 0.1% dexamethasone treatment occurs frequently in children under 10 years of age.

Indocyanine Green Facilitates Removal of Epiretinal and Internal Limiting Membranes in Myopic Eyes With Retinal Detachment

PURPOSE To describe the use of intravitreal indocyanine green as an aid to identifying epiretinal membranes and internal-limiting membranes during surgery for a retinal detachment resulting from a macular hole. METHODS A 62-year-old man who had a retinal detachment resulting from a macular hole underwent vitrectomy. During the surgery, intravitreal indocyanine green was injected intravitreally. RESULTS The internal-limiting membrane was stained green, but the epiretinal membrane was unstained. Because the epiretinal membrane and internal-limiting membrane were clearly identified, they could be completely removed. The clinical observations of the epiretinal membrane and internal-limiting membrane excised were confirmed by electron microscopy. Successful reattachment was obtained without damage to the retina. CONCLUSION Removal of epiretinal membrane and internal-limiting membrane can be facilitated by using intravitreal indocyanine green during vitrectomy. We recommend further studies to confirm the benefit of this technique.