Longitudinal Changes in Layered Retinal Thickness during Axial Elongation in Healthy Myopic Eyes

Purpose@#To investigate longitudinal changes in foveal retinal sublayer thicknesses during axial elongation. @*Methods@#From February 2013 to September 2014, a prospective cohort was established comprising pediatric patients aged 0.05, linear mixed-effects model). @*Conclusions@#The foveal retinal sublayers maintained their thicknesses despite axial elongation, indicating that the foveal retinal structure, which is critical to visual acuity, is preserved even in elongated, myopic eyes.

Relationship between Ocular Fatigue and Use of a Virtual Reality Device

PURPOSE: To investigate ocular fatigue after the use of a head-mounted display (HMD)-type virtual reality device.METHODS: Healthy adult volunteers were examined for ocular fatigue before and after watching videos for 10 min with an HMD-type virtual reality device. Subjective ocular fatigue was measured using a questionnaire. Objective fatigue was measured using the critical flicker fusion frequency (CFF), high frequency component of accommodative microfluctuation, and accommodation amplitude. The accommodation amplitude was measured using the push-up method and the dynamic measurement mode of the autorefractometer. Changes in the spherical equivalent were also measured.RESULTS: The questionnaire-based subjective ocular fatigue increased (p = 0.020) after use of the HMD device. In the dominant eye, the high frequency component of accommodative microfluctuation increased (p < 0.05). The accommodation amplitude using the push-up method was decreased in the nondominant eye (p = 0.007), and temporary myopia was observed (p < 0.05). However, there was no increase in ocular fatigue in the CFF or the accommodation amplitude using the dynamic measurement mode, which showed no significant difference before and after using the HMD device (p > 0.05).CONCLUSIONS: A subjective test and some objective tests suggested that use of the HMD-type virtual reality display increased ocular fatigue. However, no increase in ocular fatigue was measured using CFF nor in the accommodation amplitude using the dynamic measurement mode which was a limitation of the study. More studies with the aim to alleviate ocular fatigue after using HMD-type virtual reality devices are therefore needed.

Anterior Chamber Configuration Changes after Cataract Surgery in Eyes with Glaucoma

PURPOSE: To evaluate changes in anterior chamber depth (ACD) and angle width induced by phacoemulsification and intraocular lens (IOL) implantation in eyes with glaucoma, using anterior segment optical coherence tomography (AS-OCT). METHODS: Eleven eyes of 11 patients with angle-closure glaucoma (ACG) and 12 eyes of 12 patients with open-angle glaucoma (OAG) underwent phacoemulsification and IOL implantation. Using AS-OCT, ACD and angle parameters were measured before and 2 days after surgery. Change in intraocular pressure (IOP) and number of ocular hypotensive drugs were evaluated. RESULTS: After surgery, central ACD and angle parameters increased significantly in eyes with glaucoma (p < 0.05). Prior to surgery, mean central ACD in the ACG group was approximately 1.0 mm smaller than that in the OAG group (p < 0.001). Post surgery, mean ACD of the ACG group was still significantly smaller than that of the OAG group. No significant differences were found in angle parameters between the ACG and OAG groups. In the ACG group, postoperative IOP at the final visit was significantly lower than preoperative IOP (p = 0.018) and there was no significant change in the number of ocular hypotensive medications used, although clinically, patients required fewer medications. In the OAG group, the IOP and number of ocular hypotensive drugs were almost unchanged after surgery. CONCLUSIONS: The ACD and angle width in eyes with glaucoma increased significantly after phacoemulsification and IOL implantation. Postoperative ACD significantly differed between the ACG and OAG groups, whereas angle parameters did not differ.

Low Limit for Effective Signal Strength in the Stratus OCT in Imperative Low Signal Strength Cases

PURPOSE: To determine the lowest limit of signal strength that is still effective for accurate analysis of optic coherence tomography (OCT) values, we investigated the reproducibility of OCT scans by signal strength (SS). METHODS: A total of 668 subjects were scanned for measurements of retinal nerve fiber layer (RNFL) thickness using the Stratus OCT twice on the same day. The variability of overall RNFL thickness parameters obtained at different SS was analyzed and compared by repeated-measures of ANOVA and Spearman's correlation coefficient. Values of the intraclass correlation coefficient (ICC) and variability (standard deviation) of RNFL thickness were obtained. The false positive ratio was analyzed. RESULTS: When SS was 3, the variability of RNFL thickness was significantly different (low ICC, high variability) in comparison to when SS was 4 or greater. Significant negative correlations were observed between variability in RNFL thickness and signal strength. The difference of variability of average RNFL thickness between SS 4 (4.94 microm) and SS 6 (4.41 microm) was 0.53 microm. CONCLUSIONS: Clinically, the difference of variability of average RNFL thickness between SS 4 and SS 6 was quite small. High SS is important, however, when signal strength is low due to uncorrectable factors in patients in need of OCT for glaucoma and retinal disease. Our results suggest that SS 4 is the lowest acceptable limit of signal strength for obtaining reproducible scanning images.

Changes in Anterior Chamber Configuration after Cataract Surgery as Measured by Anterior Segment Optical Coherence Tomography

PURPOSE: To evaluate the changes in anterior chamber depth (ACD) and angle width induced by phacoemulsification and intraocular lens (IOL) implantation in normal eyes using anterior segment optical coherence tomography (AS-OCT). METHODS: Forty-five eyes (45 patients) underwent AS-OCT imaging to evaluate anterior chamber configuration before and 2 days after phacoemulsification and IOL implantation. We analyzed the central ACD and angle width using different methods: anterior chamber angle (ACA), trabecular-iris angle (TIA), angle opening distance (AOD), and trabecular iris surface area (TISA) in the nasal and temporal quadrants. Comparison between preoperative and postoperative measurement was done using paired t-tests and each of the angle parameters was analyzed with Pearson correlation testing. Subgroup analyses according to the IOL and axial length were performed with a general multivariate linear model adjusted for age. RESULTS: Before surgery, the mean anterior chamber angle widths were 23.21 +/- 6.70degrees in the nasal quadrant and 24.89 +/- 7.66degrees in the temporal quadrant. The mean central ACD was 2.75 +/- 0.43 mm. After phacoemulsification and IOL implantation, the anterior chamber angle width increased significantly to 35.16 +/- 4.65degrees in the nasal quadrant (p = 0.001) and 36.03 +/- 4.86degrees in the temporal quadrant (p = 0.001). Also, central ACD increased to 4.14 +/- 0.31 mm (p = 0.001). AOD, TISA, and TIA increased significantly after cataract surgery and showed positive correlation with ACA. CONCLUSIONS: After cataract surgery, the ACD and angle width significantly increased in eyes with cataract. AS-OCT is a good method for obtaining quantitative data regarding anterior chamber configuration.

Differential Expression of Stem Cell Markers and Vascular Endothelial Growth Factor in Human Retinoblastoma Tissue

PURPOSE: To investigate the relationship between vascular endothelial growth factor (VEGF) and the cancer stem cell-vascular niche complex in human retinoblastoma tissue. METHODS: Six human retinoblastoma specimens primarily enucleated for Reese-Ellsworth classification stage 5a were stained to detect cancer stem cell markers, including ABCG2 for the stem cell marker and MCM2 for the neural stem cell marker, as well as to detect VEGF for the angiogenic cytokine. Using immunofluorescence, the expression of these proteins was analyzed, and their relative locations noted. RESULTS: In non-neoplastic retina of tumor-bearing eyes, ABCG2 and MCM2 were sporadically expressed in the ganglion cell layer and the inner nuclear layer, whereas VEGF was sporadically expressed in inner retina where retinal vessels are abundantly distributed. In the tumor, ABCG2 was strongly expressed out of Wintersteiner rosettes, whereas MCM2 and VEGF were strongly stained in the rosettes. Interestingly, the outer portion of the rosettes was positive for MCM2, and the inner portion of the rosettes was positive for VEGF. CONCLUSIONS: Our data demonstrated that MCM2 and VEGF are strongly expressed in the rosettes of the tumor, which were far from the area of ABCG2-positive cells. Although VEGF might not directly contribute to the cancer stem cell-vascular niche complex, it could play some role in the differentiation of tumor cells to build up the rosettes.

The Result of Photodynamic Therapy in Chronic Central Serous Chorioretinopathy

PURPOSE: To determine the efficacy and complication of photodynamic therapy (PDT) with verteporfin in chronic central serous chorioretinopathy (chronic CSC). METHODS: The authors retrospectively examined 27 eyes of 26 patients who were diagnosed with chronic CSC and treated with PDT between February 2005 and February 2008, to determine visual acuity improvement, resolution of serous retinal detachment and occurrence of complications or recurrences. RESULTS: One month after PDT, neurosensory detachment had disappeared in all patients. In addition, visual acuity had improved in 9 eyes by two lines or more on the Snellen chart, remained unchanged in 14 eyes, and decreased in 4 eyes by two lines or more on the Snellen chart. Final visual acuity had improved in 18 eyes, and remained unchanged in 9 eyes. Choroidal neovascularization (CNV) had occurred in two patients, 9 days and 6 months after PDT. Intravitreal injection of Bevacizumab was performed and closure of CNV was obtained. One eye showed choroidal ischemia 1 month after PDT, although visual acuity was not decreased. CONCLUSIONS: PDT appears to be an effective treatment for chronic CSC, and the recurrence rate after PDT is low. However, CNV may occur after PDT. Further studies are necessary to verify treatment safety and modulate the parameters of PDT to reduce complications such as CNV.

A Case of Green Laser Pointer Injury to the Macula

PURPOSE: We report a case of macular injury by accidental exposure to a green laser pointer. CASE SUMMARY: A 25-year-old man had an acute reduction of visual acuity in his right eye two years ago after accidental exposure to a green laser pointer for a few seconds. The patient's best corrected visual acuity was counting fingers in his right eye. Fundus examination and optical coherence tomography showed a macular hole and a linear retinal scar in his right eye. CONCLUSIONS: Green laser pointers may cause macular damage after exposure of just a few seconds, which can lead to irreversible reduction of visual acuity.