Takuya Nitta

Reduction of Intraocular Pressure Using a Modified 360-degree Suture Trabeculotomy Technique in Primary and Secondary Open-Angle Glaucoma: A Pilot Study

PurposeTo investigate the effects of a modified 360-degree suture trabeculotomy technique for primary and secondary open-angle glaucoma (POAG and SOAG). MethodsWe modified the procedure for 360-degree trabeculotomy by using a 5-0 nylon suture, making a scleral flap to allow clear identification of Schlemm canal, and creating a corneal side port incision opposite to the scleral flap to retrieve the suture used to cannulate and cleave the canal. The modified 360-degree suture trabeculotomy (not combined with cataract surgery) was performed on 25 eyes with POAG and 18 eyes with SOAG, and the results were compared retrospectively with those of standard trabeculotomy with metal trabeculotomes (16 eyes with POAG and 19 eyes with SOAG). When the intraocular pressure (IOP) was reduced by 30% from the preoperative IOP and was also below 18 mm Hg at 3, 6, 9, 12, and 18 months after surgery and the patient was taking a similar number or fewer medications, the surgery was considered a “success.” ResultsUsing this modified technique, Schlemm canal was appropriately incised without resistance. At 12 months after the modified 360-degree suture trabeculotomy and trabeculotomy with metal trabeculotomes, the mean postoperative IOP values were 13.1 and 15.2 mm Hg, respectively, and the mean numbers of antiglaucoma medications were 0.5 and 1.4, respectively. The success rates of POAG at 12 months for the modified 360-degree suture trabeculotomy and trabeculotomy with metal trabeculotomes were 84% and 31%, respectively, and those of SOAG were 89% and 50%, respectively. The complications included a transient elevation of the IOP above 30 mm Hg in 22 eyes (47%) treated with the 360-degree suture trabeculotomy and 17 eyes (49%) treated with trabeculotomy with metal trabeculotomes. There was no significant difference between preoperative visual acuity and postoperative visual acuity in either procedure. ConclusionsThis modified 360-degree suture trabeculotomy is a feasible surgical option for POAG and SOAG.

Predictive signals in the pursuit area of the monkey frontal eye fields.

In order to pursue a moving target with our eyes, visual motion-signals are converted into eye movement commands. Because of delays in processing visual information, prediction is necessary to compensate for those response-delays and maintain target images on the foveae. Previous studies showed that the majority of FEF pursuit neurons receive visual signals related to actual and predicted target motion. However, in those studies, discharge related to the memory of visual motion could not be separated from that related to prediction. To distinguish the two, while fixating a stationary spot, monkeys were required to memorize the direction of random dot motion (cue-1). After a delay (delay-1), a second cue (cue-2) instructed the monkeys to prepare either pursuit in the memorized direction or to maintain fixation. After a second delay (delay-2), the monkeys selected the correct response. In virtually all tested neurons that showed a visual motion-response to cue-1, the response was not maintained during the delay-1. The majority of responsive neurons were modulated during cue-2 and delay-2. Changing the delay-2 duration also changed the duration of discharge modulation, suggesting that delay-2 modulation was predictive. These results suggest that activity related to visual motion-memory was not conveyed by the discharge of caudal FEF pursuit neurons.

Vergence eye movement signals in the cerebellar dorsal vermis.

We examined simple-spike activity of Purkinje cells (P-cells) that responded during a search task which required both vergence- and frontal-pursuit. Of a total of 100 responding P-cells, 16% discharged only for frontal-pursuit, 43% only for vergence-pursuit, and 41% for both. Thus, the majority of vermal pursuit P-cells modulated their activity during vergence-pursuit. These P-cells also discharged for vergence eye movements induced by step target-motion in-depth. The majority of vergence related P-cells carried convergence signals with both eye velocity and position sensitivities, and they discharged before the onset of convergence eye movements. Muscimol infusion into the sites where convergence P-cells were recorded resulted in a reduction of peak convergence eye velocity, of initial convergence eye acceleration, and of frontal-pursuit eye velocity. These results suggest specific involvement of the dorsal vermis in vergence eye movements.

Mydriasis with Light-Near Dissociation in Fisher's Syndrome

BackgroundApproximately 50% of patients with Fishers syndrome show involvement of the pupillomotor fibers and present with mydriasis and light-near dissociation. However, it is uncertain whether this phenomenon is induced by an aberrant reinnervation mechanism as in tonic pupil, or is based on other mechanisms such as those associated with tectal pupils.CasesWe evaluated the clinical course and the pupillary responses in four of 27 patients with Fishers syndrome who presented with bilateral mydriasis.ObservationsThe pupils of both eyes of the four patients were involved at the early stage of Fishers syndrome. The pupils in patients 1 and 2 showed mydriasis with apparent light-near dissociation lasting for a significant period and had denervation supersensitivity to cholinergic agents. On the other hand, the pupils of patients 3 and 4 were dilated and fixed to both light and near stimuli.ConclusionsOur observations indicate that the denervated iris sphincter muscles, which are supersensitive to the cholinergic transmitter, may play an important role in the expression of light-near dissociation in Fishers syndrome. Jpn J Ophthalmol 2007;51:224–227

Ocular motor disorders in mitochondrial encephalopathy with lactic acid and stroke-like episodes with the 3271 (T-C) point mutation in mitochondrial DNA.

Background: Ocular motor function can provide insights into areas of dysfunction within the nervous system. There are no published eye movement recordings in patients with mitochondrial encephalopathy with lactic acid and stroke-like episodes (MELAS). Our purpose in this study was to analyze the ocular motor features of a family with MELAS with a (T-C) mutation at nucleotide position 3271 in the mitochondrial tRNA-Leu gene. Methods: The search coil method was used to record visually-guided saccades, antisaccades, and triangular pursuit tasks in the horizontal and vertical planes in three patients in a Japanese family with MELAS. Results: The patients showed saccadic dysmetria and prolonged saccadic reaction times, deficits in the ability to suppress reflex eye movements, and increased reaction time during antisaccades, downbeat nystagmus, square wave jerks, and impairment in pursuit. Conclusions: On the basis of eye movement recordings, patients with MELAS have frontal cortex as well as cerebellar dysfunction.

Central serous retinal detachment detected by optical coherence tomography in Leber's idiopathic stellate neuroretinitis.

Lebers idiopathic stellate neuroretinitis (LISN) is characterized mainly by bifocal lesions, namely, optic neuritis and maculopathy with starlike exudates. However, it is unclear how the macular region is involved. 1 - 4 In our patient with LISN, optical coherence tomography (OCT) revealed central serous retinal detachment with exudates in the retinal outer plexiform layer.

Arteritic anterior ischemic optic neuropathy with positive myeloperoxidase antineutrophil cytoplasmic antibody

BackgroundMyeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is related to smallvessel vasculitis. There have been some reports of optic nerve involvements with increased values of MPO-ANCA. We report two cases of anterior ischemic optic neuropathy (AION) in which ANCA-associated vasculitis was suspected to be responsible for the pathogenesis.CasesA 66-year-old man and a 72-year-old man had ocular symptoms of AION in both eyes with positive MPO-ANCA.ObservationsBoth patients showed high erythrocyte sedimentation rate, C-reactive protein, and MPOANCA values at first. Temporal artery biopsies were negative for temporal arteritis, whereas small-vessel vasculitis was found only in the latter patient. Visual dysfunctions remained unchanged after steroid pulse therapy, although laboratory data returned to normal levels after the treatment. Fluorescein angiography revealed selective occlusion of capillaries, arterioles, and precapillaries in the retina and choroid as well as in the optic disc.ConclusionsThe identical characteristics of the angiographic findings of both eyes in the two cases indicated that the obliteration of small vessels in the intraocular arterial system was closely related to MPO-ANCA-associated vasculitis.

Modified 360-degree suture trabeculotomy combined with phacoemulsification and intraocular lens implantation for glaucoma and coexisting cataract

Purpose To assess the efficacy and safety of a modified 360‐degree suture trabeculotomy combined with a cataract surgery technique in patients with glaucoma and coexisting cataract. Setting Hokkaido University Hospital, Sapporo, Japan. Design Retrospective case series. Methods Medical records of patients with glaucoma having a modified 360‐degree trabeculotomy combined with cataract surgery (Group 1) were reviewed. Another group of patients who had the modified 360‐degree suture trabeculotomy alone served as controls (Group 2). Results Both groups comprised 46 patients. In each group, eyes were diagnosed with primary angle‐closure glaucoma in 2 eyes, primary open‐angle glaucoma in 24 eyes, exfoliation glaucoma in 4 eyes, uveitic glaucoma in 15 eyes, and steroid glaucoma in 1 eye. The mean preoperative intraocular pressure (IOP) values were 27.2 mm Hg ± 7.3 (SD) on 3.0 ± 0.5 medications in Group 1 and 27.7 ± 10.7 mm Hg on 2.9 ± 0.6 medications in Group 2. Twelve months after surgery, the mean IOPs were 13.4 ± 3.7 mm Hg on 0.8 ± 1.1 medications in Group 1 and 13.9 ± 4.1 mm Hg on 0.6 ± 0.9 medications in Group 2. The success rate (<18 mm Hg) at 12 months was 89.1% and 93.5%, respectively. Major complications included transient IOP spikes (30.4% and 37.0%) and prolonged hyphema (10.9% and 6.5%) in Group 1 and Group 2, respectively. Conclusion The data showed the equivalent effects of suture trabeculotomy combined with cataract surgery and suture trabeculotomy surgery alone on postoperative safety and efficacy. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.

Long-Term Evaluation of Visual Field Alteration in Leber's Hereditary Optic Neuropathy with Visual Recovery

A 14-year-old girl who was diagnosed as having Lebers hereditary optic neuropathy with the 11778 mutation in the mitochondrial DNA was followed up by investigating the visual field alteration periodically over a three-year period. She was first seen with a sudden decrease of visual acuity in the right eye. Goldmanns perimetry showed a large central scotoma in the right eye and small relative scotomas in the upper part of the left eye which was still asymptomatic. Visual acuity in the left eye, however, decreased two months later. At that time, a large absolute central scotoma was detected. The absolute central scotomas in both eyes gradually shrank to change to a relative one in one and a half years after the onset, sequentially leading to an increase of visual acuity which was finally 0.15 OD and 1.0 OS. The long-term evaluation in our case indicated that the development of visual field changes was almost identical in both eyes and that slow recovery of visual acuity was a result of the gradual shrinkage to breakthrough of central scotoma.