Development and spontaneous closure of a secondary macular hole associated with submacular hemorrhage due to polypoidal choroidal vasculopathy: a case report.

BACKGROUND: Macular hole (MH) is a retinal break in the fovea involving partial or complete dehiscence of the neural retinal layers affecting the visual quality by decreasing visual acuity (VA) and visual deformation. We describe a case of secondary MH associated with submacular hemorrhage (SMH) due to polypoidal choroidal vasculopathy (PCV), which showed spontaneous closure. CASE PRESENTATION: A 67-year-old man developed decreased VA in his right eye due to an SMH. The VA was 20/50, and monthly intravitreal injection of aflibercept was administered three times. The SMH gradually decreased, and 10 months later the external limiting membrane was found to be perforated, resulting in MH. The old clot disappeared, and the MH remained for 10 months. Twenty-three months later, serous retinal detachment (SRD) involving the macula appeared and the MH had disappeared. SRD gradually disappeared, and macular configuration recovered. VA gradually improved and became 20/20 38 months later. CONCLUSION: Dynamic change of the ultrastructure in an unusual case of secondary-developed and spontaneously closed MH was clearly observed. Although the mechanism was unknown, the small diameter size and exudative PCV are thought to have contributed to the closure.

Electroretinograms Recorded with Skin Electrodes from Post-Vitrectomy Silicone Oil Filled Eyes with Proliferative Diabetic Retinopathy.

Purpose: To determine the physiological status of the retina by electroretinography (ERG) using skin electrodes and the RETevalTM system in eyes that had undergone pars plana vitrectomy (PPV) with silicone oil (SO) tamponade. The vitrectomy was performed for a retinal detachment and proliferative diabetic retinopathy (PDR). Design: Retrospective case series. Methods: ERGs were recorded with the RETevalTM system (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn, Inc. Skaneateles Falls, NY) from eight eyes with PDR before and after the SO removal. The amplitudes and implicit times of the a- and b-waves of the ERGs before the SO removal were compared to that after the SO removal. Results: ERGs were recordable in four eyes before and after the SO removal and the a- and b-amplitudes improved in three eyes and worsened in one eye after the SO removal. In the remaining four eyes, ERGs were non-recordable both before and after the SO removal. Conclusion: These results indicate that ERGs picked up by skin electrodes can be used to assess the physiology of the retina in eyes with a SO tamponade. The flat ERGs in the SO-filled eye indicated the presence of diffuse retinal damage which was confirmed by the flat ERGs after the SO removal.

There has been an increasing number of reports on evaluating the retinal function using electroretinography (ERG) with skin electrodes. The main advantage of this system is the ability to record ERGs with a skin electrode that does not touch the cornea and ocular surface. This reduces the risk of infection especially in the postoperative period and in clinical situations where infection is suspected. In addition, there have been only a few reports evaluating the function of the retina by ERG in SO-filled eyes. We recorded ERGs with the RETeval (LKC Technologies Inc. Gaithersburg, MD; Welch Allyn Inc. Skaneateles Falls, NY) device, a relatively new ERG recording system that uses skin electrodes and is less invasive. We recorded ERGs from eight SO-filled eyes with proliferative diabetic retinopathy (PDR). In 4 SO filled eyes, the amplitudes increased in three eyes after the SO removal. In the other four eyes, ERGs were non-recordable before and after the SO removal. These results suggest that the RETeval system that uses skin electrodes can be used to assess the retinal function in PDR eyes with a SO tamponade. We suggest that the absence of ERGs in the SO filled eyes was not due to the electrical non-conductive effects of SO but may indicate the presence of diffuse retinal damage which was confirmed after the SO removal.

Electroretinographic Evaluations of Eyes With Endophthalmitis.

Purpose: To determine the physiological status of the retina of eyes with endophthalmitis by examining the electroretinograms (ERGs) recorded with a portable recording system and to determine whether the pretreatment ERG findings were correlated with the best-corrected visual acuity (BCVA) after the treatment. Methods: We examined the medical records of 118 eyes of 108 patients who were diagnosed and treated for infectious endophthalmitis at Saitama Medical University Hospital, Japan, between January 2015 to November 2022. Of these, we studied the 25 eyes of 21 patients who had been evaluated by electroretinography. In bilateral cases, one eye was analyzed. The eyes were classified into those with postoperative endophthalmitis (group S, n = 12) and those with endogenous endophthalmitis (group E, n = 9). Photopic and flicker ERGs were recorded with the RETeval system. The pretreatment clinical factors studied were the ERG components that might be correlated with the post-treatment BCVA. Results: Eyes in Group E with larger amplitude flicker ERGs (P = 0.0053, ρ = -0.8333) had better BCVA after treatment. In Group S, eyes with larger amplitude flicker ERGs (P = 0.0086, ρ = -0.7173), photopic a-waves (P = 0.0323, ρ = 0.6177), and photopic b-waves (P = 0.0055, ρ = -0.7443) had better BCVA after treatment. Conclusions: Simple and rapid ERG evaluations under light-adapted condition are helpful in evaluating the pretreatment retinal function and to determine the visual prognosis in eyes with endophthalmitis. Translational Relevance: Simple and non-time-consuming ERG evaluations are helpful in evaluating the retinal function in eyes with endophthalmitis and predicting the visual prognosis.

Case of Spontaneous Closure and Recurrence of Macular Hole in Vitrectomized Eye.

Rationale: Development and spontaneous closure of a macular hole (MH) in a vitrectomized eye is relatively rare. We report our findings in a case in which vitrectomy was performed successfully to treat a vitreous hemorrhage (VH), but a MH developed eight months later. The MH spontaneously closed 2 weeks later, but then reopened. A second vitrectomy was performed with insertion of the internal limiting membrane flap into the MH which led to the successful closure of the MH. The purpose of this article is to present an explanation of how MH developed in this eye without vitreous traction. Patient: A 64-year-old woman visited an eye clinic with vision reduction in her right eye of 3 days duration. A VH was detected in the right eye and pars plana vitrectomy (PPV) was performed. A retinal tear was detected which was the origin of the VH. The vision was restored to a decimal visual acuity of 1.2. Eight months later, the patient noticed that her vision was distorted and was referred to our hospital. Diagnosis: Optical coherence tomographic (OCT) images showed a thin epiretinal membrane on the macula, cystoid changes in the macular area, and a full-thickness MH. Interventions: The MH closed spontaneously in two weeks, however a lamellar MH with an epiretinal proliferation (EP) developed 11 months later. Two months later, OCT showed cyst-like changes in the retina and a full-thickness MH. A second PPV was performed with the insertion of the ILM flap and EP into the MH to close the MH. Her visual acuity improved, and distorted vision was not present. Lessons: Clinicians should be aware that a MH can develop in a vitrectomized eye without vitreous traction but can close spontaneously. We conclude that careful follow-up examinations are necessary even in vitrectomized eyes.

Electroretinographic and Optical Coherence Tomographic Evaluations of Eyes with Vitreoretinal Lymphoma.

Vitreoretinal lymphomas (VRLs) present with different clinical characteristics. However, only a few case reports have been published that evaluated the retinal function and the retinal morphology. The relationship between retinal morphology and function of eyes with a vitreoretinal lymphoma (VRL) was investigated via optical coherence tomography (OCT) and electroretinography (ERG). The ERG and OCT findings in 11 eyes of 11 patients (69.4 ± 11.5 years old) who were diagnosed with VRL at the Saitama Medical University Hospital between December 2016 to May 2022 were studied. The decimal best-corrected visual acuity ranged from hand movements to 1.2 (median 0.2). Histopathological studies of the vitreous specimens showed class II VRL in one eye, class III VRL in seven eyes, class IV VRL in two eyes, and class V VRL in one eye. The IgH gene rearrangement was positive in three of the six eyes tested. The OCT images showed morphological abnormalities in 10 of the 11 (90.9%) eyes. Severe attenuation was found for the amplitudes of the b-wave of the DA 0.01 ERG in 6 of 11 eyes (54.5%), the DA 3.0 a-wave in 5 of 11 eyes (45.5%), the DA 3.0 b-wave in 36.4%, the LA 3.0 a-wave in 36.4%, the LA 3.0 b-wave in 18.2%, and flicker responses in 36.4% of the eyes. None of the DA 3.0 ERGs had a negative shape (b/a < 1.0). In the five eyes in which the a-wave was severely attenuated, hyperreflective dots were observed subretinally. The ERG analysis in eyes with a VRL indicates a relatively severe dysfunction of the outer retinal layer and was helpful in determining the site of the morphological changes in eyes with VRL.

A Case of Intraocular Lymphoma Diagnosed by Subretinal Fluid Biopsy.

Although intraocular lymphoma (IOL) mainly has have vitreous opacity and subretinal infiltration, its clinical symptoms are diverse. We report a case of IOL that mainly showed exudative retinal detachment in which analysis of IgH gene rearrangement (AIGHR) of the collected subretinal fluid sample was useful for diagnosis. A 77-year-old woman developed decreased left visual acuity for 1 month. She had been treated for dermatomyositis, diabetes mellitus, and right parotid tumor for 3 years. Visual acuity was 0.1 OD and counting fingers OS. Slit-lamp examination showed grade 4 (Emery-Little classification) nuclear cataract in both eyes and keratoprecipitates and tan vitreous opacity in the left eye. Fundoscopy details were unclear except for a vaguely observable optic nerve head due to yellow-brown vitreous opacity, which we judged as an old vitreous hemorrhage. Phacovitrectomy was performed and almost total retinal detachment was found, except for a part of the superior periphery. Since no retinal break was found and a wide range of thin membrane-like tissue was found on the surface of the retina, the surgeon suspected primary IOL and performed unplanned biopsy. The peripheral vitreous was collected as a sample, and then the subretinal fluid was collected through an intentional break to prevent mixing with other fluids. The subretinal strand was gently removed and collected. Cytology showed class III, the IL10/IL6 ratio was low, and AIGHR was positive. Postoperatively, fundus autofluorescence showed no abnormality, no leakage was observed on fluorescein and indocyanine green angiography, and the location of typical infiltration lesions under the retina was unclear. There were no positive findings on systemic examinations and a diagnosis of primary IOL was made. The main symptoms of this case were vitreous opacity and exudative retinal detachment, and AIGHR using subretinal fluid was useful for diagnosis.

Transient Increase and Delay of Multifocal Electroretinograms Following Laser Photocoagulations for Diabetic Macular Edema.

BACKGROUND: The acute physiological changes induced by focal retinal photocoagulation (PC) have been largely unexplored. METHODS: This was a case-series study. We recorded multifocal electroretinograms (mfERGs) just before PC, and mfERGs were also recorded 5', 15', one hour, 24 h, and one week after the PCs. Transient changes of mfERGs were analyzed in eyes which underwent PCs to treat diabetic macular edema. The mfERGs recorded from the predominantly irradiated area and that from non-irradiated areas were analyzed separately. RESULTS: Fifteen eyes of 15 patients were included in this study. The mfERGs elicited from non-irradiated areas did not change after PC, but the mfERGs elicited from the irradiated area changed with time; the amplitude was larger at 60' than that before (p < 0.05) and at 5' after PC (p < 0.01) and significantly smaller at 24 h and 1 week than that before and at 60' after the PC (p < 0.01). The implicit time was significantly prolonged after PC. mfERG on irradiated area with the severe diabetic change was less altered after PCs. CONCLUSIONS: The transient increase in the amplitude at 60' likely resulted from a biological amplification of partially damaged cells adjacent to the PC spots. The mfERGs manifested the dynamic alterations of the retinal function following PCs.

Quantitative assessment of macular function after surgery for optic disc pit maculopathy: A case report.

RATIONALE: We describe a case of optic disc pit maculopathy (ODP-M) in which vitrectomy with juxtapapillary laser (JPL) treatment led to the reattachment of retinoschisis (RS) as well as serous retinal detachment (SRD). PATIENT CONCERNS: An 80-year-old man complained of distorted vision and decreased visual acuity (VA) in his left eye for 12 months. DIAGNOSIS: We conducted quantitative functional evaluation on the area of RS and SRD using the Humphrey visual field analyzer. Fundus examination and optical coherence tomography showed SRD and RS in connection with the optic disc. The best-corrected logarithm of the minimum angle of resolution (logMAR) VA was 0.7. INTERVENTIONS: The patient underwent JPL treatment combined with pars plana vitrectomy. During surgery, posterior vitreous detachment and tamponade were created with sulfur hexafluoride. OUTCOMES: After surgery, SRD (and subsequently RS) gradually reduced and had completely disappeared at 31 months. VA gradually improved and was 0.0 (logMAR) at 28 months. The analysis of the mean macular thickness of the central 3-mm diameter showed that the macula thickness recovered to 300 µm at 17 months postoperatively. Retinal sensitivity began to improve at 24 months postoperatively and had increased at 48 months postoperatively. LESSONS: In conclusion, vitrectomy with JPL treatment for ODP-M had a favorable anatomical outcome as well as a long-term functional outcome. These findings provide useful information for clinicians who are planning a therapeutic strategy, including the choice of surgical procedure for ODP-M.

Author Correction: Electroretinographic recordings with skin electrodes to assess effects of vitrectomy with gas tamponade on eyes with rhegmatogenous retinal detachment.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Correction: Electroretinograms recorded with skin electrodes in silicone oil-filled eyes.

[This corrects the article DOI: 10.1371/journal.pone.0216823.].

Extrinsic factors derived from mouse embryonal carcinoma cell lines maintain pluripotency of mouse embryonic stem cells through a novel signal pathway.

Embryonic carcinoma (EC) cells, which are malignant stem cells of teratocarcinoma, have numerous morphological and biochemical properties in common with pluripotent stem cells such as embryonic stem (ES) cells. However, three EC cell lines (F9, P19 and PCC3) show different developmental potential and self-renewal capacity from those of ES cells. All three EC cell lines maintain self-renewal capacity in serum containing medium without Leukemia Inhibitory factor (LIF) or feeder layer, and show limited differentiation capacity into restricted lineage and cell types. To reveal the underlying mechanism of these characteristics, we took the approach of characterizing extrinsic factors derived from EC cells on the self-renewal capacity and pluripotency of mouse ES cells. Here we demonstrate that EC cell lines F9 and P19 produce factor(s) maintaining the undifferentiated state of mouse ES cells via an unidentified signal pathway, while P19 and PCC3 cells produce self-renewal factors of ES cells other than LIF that were able to activate the STAT3 signal; however, inhibition of STAT3 activation with Janus kinase inhibitor shows only partial impairment on the maintenance of the undifferentiated state of ES cells. Thus, these factors present in EC cells-derived conditioned medium may be responsible for the self-renewal capacity of EC and ES cells independently of LIF signaling.

Electroretinographic recordings with skin electrodes to assess effects of vitrectomy with gas tamponade on eyes with rhegmatogenous retinal detachment.

The purpose of this study was to evaluate the retinal function by electroretinograms (ERGs) recorded with the RETeval system using skin electrodes after pars plana vitrectomy (PPV) with gas tamponade in eyes with a rhegmatogeneous retinal detachment (RRD). Flicker ERGs were recorded from 17 eyes with an RRD before (baseline), within 2 weeks after the PPV when the size of the tamponade gas was approximately one-half of the vitreous cavity (P1), and when the gas had been completely absorbed (P2). The amplitudes of the flicker ERGs at each phase were compared to that at the baseline. The median (25th, 75th percentile) of the amplitude was 10.0 µV (5.5, 13.0 µV) at the baseline, 11.7 µV at P1 (7.8, 14.8 µV; P = 0.003), and 17.1 µV at P2 (11.7 23.3 µV; P < 0.001). The ratio of the amplitudes in the affected eye to that in the fellow eye at the baseline and at each phase was calculated, and the ratio of the amplitudes at P1 and P2 were significantly and positively correlated (P = 0.723, P = 0.001; Spearman's rank correlation coefficient). We conclude that recordings the flicker ERGs with skin electrodes can be used to assess the physiology of eyes even with the vitreous cavity half-filled with the gas used to tamponade the retina.

Electroretinograms recorded with skin electrodes in silicone oil-filled eyes.

PURPOSE: To assess the physiology of the retina by electroretinography (ERG) with skin electrodes in eyes that had undergone vitrectomy with silicone oil (SO) tamponade. DESIGN: Retrospective case series. METHOD: ERGs were recorded from eleven eyes with complex vitreoretinal disorders and from the normal fellow eyes. The affected eyes underwent pars plana vitrectomy (PPV) with SO tamponade. ERGs were recorded before and after the SO was removed. The amplitudes and implicit times of the a- and b-waves of the affected eyes were compared to those of the normal fellow eyes. In addition, the ratios of the amplitudes of the b-waves of the affected eyes to those of the fellow eyes were compared before and after the SO was removed. RESULTS: ERGs were recordable from 7 eyes (63.6%) before the SO was removed and 11 eyes (100%) after the SO was removed. The a- and b-wave amplitudes were significantly smaller in the affected eyes than those of the fellow eyes at the baseline. The b-wave amplitude before the removal of the SO was significantly and positively correlated with that after the SO removal. The ratios of the b-waves of the affected/normal fellow eye significantly increased after the SO was removed. CONCLUSION: The results indicate that ERGs picked up by skin electrode can be used to assess the physiology of the retina in eyes with a SO tamponade. The amplitude of the b-waves of the ERGs in silicone-filled eyes can be used to predict the amplitude after the silicone is removed.

Macular Structure Recovery after Surgery for Optic Disc Pit Maculopathy.

The present report aimed to describe the macular structure's recovery process in a case of optic disc pit maculopathy (ODP-M) with outer layer hole following pars plana vitrectomy (PPV) with juxtapapillary laser treatment (JPL). We performed repeated optical coherence tomography (OCT) examinations to evaluate the macular structural changes. An 80-year-old man presented with distorted vision and decreased visual acuity (VA) in his left eye, experienced for 1 year, prior to presentation. Fundus examination and OCT showed intraretinal fluid (IRF) in the inner and outer retinal layers. Serous retinal detachment (SRD) with an outer layer hole in the macula was also evident. The IRF was connected to the optic disc; however, the SRD was isolated. Best-corrected VA was 20/100. PPV combined with JPL was performed. Posterior vitreous detachment creation and tamponade with sulfur hexafluoride was performed. Postoperatively, the inner retinal IRF at the fovea disappeared. The outer layer hole gradually closed and had completely disappeared 1 month postoperatively. After resolution of the outer layer hole, SRD reduced gradually and disappeared 8 months postoperatively, although the macular outer retinal IRF remained. The outer retinal IRF had partially resolved by the 18th postoperative month. Macular structure was completely recovered 31 months postoperatively, with an improved VA of 20/20. In conclusion, SRD might be associated with outer retinal IRF and outer layer holes. In cases of ODP-M, outer layer holes might induce optic disc-isolated SRD.

Heads-Up 3D Surgery under Low Light Intensity Conditions: New High-Sensitivity HD Camera for Ophthalmological Microscopes.

PURPOSE: To determine the feasibility of performing intraocular surgeries in a heads-up position with low illuminance conditions by observing a display of the surgical field created by a three-dimensional imaging (3D) system. METHODS: Seventy-four eyes of 56 patients underwent cataract surgery (72 eyes) with the heads-up 3D surgery system; 60 eyes with cataract surgery alone, 7 eyes with combined cataract and glaucoma microdevice implant surgery, 5 eyes with combined cataract and vitrectomy surgery, and two eyes with vitrectomy surgery alone were studied. The illuminance from the surgical microscope was set to be dimmer (Leica M822F40 main light 2%; otto-flex 6%) than the usual setting to minimize the discomfort and glare for the patient. The surgeries were performed under topical anesthesia. The luminance of the images observed through the eyepieces of the operating microscope and the image of a 3D system created by a high-sensitivity sensor Exmor R 3CMOS HD camera (Sony MCC-1000MD) were measured. RESULTS: All surgeries were completed without any complications under the low illumination conditions. The surgical field on the display monitor was created by a 3D system using a high-sensitivity sensor camera and was observed in a heads-up position. The patients did not report any intolerable discomfort or glare during the surgery. Cataract surgeries were performed with a good view of the surgical field under the extremely low illumination from the surgical microscope. The high-sensitivity sensors and electronic amplifications of the image signals made the surgical field brighter and allowed the surgeon to perform the surgery confidently and safely. CONCLUSIONS: Heads-up, 3D-assisted intraocular surgeries can be performed safely and efficiently with low illuminance of the surgical field. This trial is registered with UMIN000037838.

Histopathologic changes in serum bile acid fractions in pressure ulcer patients.

BACKGROUND/AIMS: Bile acids are synthesized in the liver and released into the intestinal tract to aid in digestion and absorption by increasing permeability via alteration of the cell membrane. Bedridden elderly patients typically have pressure ulcers that may be due to both physical local pressure as well as skin cell changes induced by the physiologic effects of bile acids. METHODOLOGY: This study investigated 31 elderly bedridden patients with pressure ulcers (mean age, 81.7 years) and 19 healthy elderly (mean age, 79.7 years). Five serum bile acid fractions were summed to determine total bile acid, and transaminase and cholesterol levels were also measured. RESULTS: Total cholesterol levels were significantly lower (p<0.05) in pressure ulcer patients and transaminase levels were not significantly different between the two groups. The primary bile acids were generally higher and the secondary and tertiary bile acids lower in pressure ulcer patients. In particular, the secondary bile acid deoxycholic acid was significantly higher in all pressure ulcer patients. When analyzed by grade of pressure ulcer, the primary bile acids were significantly lower in pressure ulcer patients. CONCLUSIONS: Secondary bile acid fraction deoxycholic acid measurements may indicate bedridden patients at higher risk for pressure ulcers.

Endothelial nitric oxide synthase gene is associated with diabetic macular edema in type 2 diabetes.

OBJECTIVE: We examined the endothelial nitric oxide (eNOS) gene polymorphisms to assess its possible association with diabetic retinopathy and macular edema. RESEARCH DESIGN AND METHODS: A total of 226 patients with type 2 diabetes and 186 healthy subjects were studied. Type 2 diabetic patients consisted of 110 patients without retinopathy, 46 patients with nonproliferative diabetic retinopathy, and 71 patients with proliferative diabetic retinopathy. Diabetic macular edema was present in 48 patients. Three polymorphisms of the eNOS gene were determined: T-786C in the promoter region, 27-bp repeat in intron 4, and Glu298Asp in exon 7. RESULTS: Close linkage disequilibrium was observed between the T-786C polymorphism and the 27-bp repeat, as has been previously reported, but Glu298Asp was not in linkage disequilibrium with the other two polymorphisms. The eNOS gene polymorphisms were not significantly associated with the presence of retinopathy or with retinopathy severity or type 2 diabetes itself. However, by both association study and multiple logistic regression analysis, the T-786C and 27-bp repeat polymorphisms were significantly associated with a risk of developing macular edema with the -786C allele and the "a" allele increasing the risk. CONCLUSIONS: The present study suggests that the eNOS gene is a novel genetic risk factor for diabetic macular edema. The eNOS gene polymorphisms may contribute to the development of macular edema by impairing basal eNOS expression and resulting in the breakdown of the blood-retina barrier.

Fluid extravasation of the articular capsule as a complication of temporomandibular joint pumping and perfusion.

This report is a retrospective study of fluid extravasation as a complication of temporomandibular joint pumping and perfusion. Contrast-enhanced 3D-CT of the upper joint compartment was performed for presurgical diagnosis before temporomandibular joint arthroscopic surgery in our hospital from 1996 to 2000. From these cases, 43 joints and 38 patients were selected because they had not improved under conservative treatment during the previous six months. Fluid extravasation of the articular capsule was recognized in 9 joints (20.9%) in 9 patients, 3 males and 6 females. Two of the nine patients had undergone arthroscopic observation before surgery. This test had revealed only thin articular capsule, not a perforation, in any of these cases. The data indicate only extremely tiny perforations or infiltration leakage due to the fluid pressure in the upper joint compartment during pumping or perfusion. Oral and maxillofacial surgeons should be aware of this complication.

Direct one-pot synthesis of alpha-siloxy-Weinreb amides from aldehydes.

A one-pot method for synthesizing alpha-siloxy-Weinreb amides from aldehydes was developed with use of N,O-dimethylhydroxylamine and a masked acyl cyanide reagent bearing a tert-butyldimethylsilyl group avoiding the competitive reaction toward N-methoxy-N-methyl-2-amino-1-siloxymalononitrile.

Synthesis of alpha-amino acid precursors directly from aldehydes using masked acyl cyanide reagents and N,O-dialkylated hydroxylamines.

A synthetic methodology for the synthesis of alpha-amino acid precursors directly from the corresponding aldehydes using N,O-dialkylated hydroxylamines and masked acyl cyanide (MAC) reagents was developed. The one-pot reaction can be carried out under mild conditions and without a separate purification step of the imino species. The method was applied to the synthesis of optically pure (+)-4-methylphenylglycine and the derivatives by using an Abiko-Masamune's tricyclic 1,2-oxazolidine as the chiral auxiliary.