Chihiro Mayama

Transient but Significant Visual Field Defects after Robot-Assisted Laparoscopic Radical Prostatectomy in Deep Trendelenburg Position

Background Robot-assisted laparoscopic radical prostatectomy (RALP) is a minimally invasive surgical procedure for prostate cancer. During RALP, the patient must be in a steep Trendelenburg (head-down) position, which leads to a significant increase in intraocular pressure (IOP). The association of RALP with visual field sensitivity, however, has not been prospectively studied. The purpose of this study was to evaluate prospectively the visual field, retinal nerve fiber layer (RNFL) thickness, and optic disc morphology in 50 normal eyes of 25 male patients that underwent RALP. Methods The subjects were 25 males among 33 consecutive patients who underwent uneventful RALP under general anesthesia in our hospital. Visual field tests using the Humphrey visual field analyzer 30-2 SITA-standard program were performed before, 7 days after, and 1-3 months after RALP. IOP was measured before, during, and after RALP; and ophthalmologic examinations, including slit-lamp, fundus examination, and optical coherence tomography (OCT), were scheduled before and 7 days after surgery. Results IOP was significantly increased during RALP up to 29.4 mmHg (P<0.01). Postoperative local visual field defects were detected in 7 eyes of 7 subjects dominantly in the lower hemifield without abnormal findings in the optic nerve head or retina, and the visual field recovered to normal within 3 months after surgery. General factors associated with RALP, IOP, RNFL thickness, or optic disc parameters did not differ significantly between eyes with and without postoperative visual field defects, and parameters of OCT measurements were not altered after surgery. Conclusion Transient but significant unilateral visual field defects were found in 28% of the subjects examined. The probable cause are the increased IOP and altered perfusion during surgery and ophthalmologic examinations are therefore suggested before and after RALP.

Myopia and advanced-stage open-angle glaucoma

OBJECTIVE To investigate the effect of myopic refraction on the central visual field in patients with advanced open-angle glaucoma (OAG). DESIGN Multicenter cross-sectional study. PARTICIPANTS Three hundred thirteen OAG eyes (176 eyes of 176 primary open-angle glaucoma [POAG] patients and 137 eyes of 137 normal-tension glaucoma [NTG] patients) with clear ocular media and a mean deviation (MD) <-15 dB. Patients with a recorded maximum intraocular pressure (IOP) of 22 mmHg or greater were classified as POAG, and those with an IOP of 21 mmHg or less were classified as NTG. METHODS Multiple regression analysis was used to study the influence of refraction on 12 central test points of the C30-2 Humphrey program, and the differences in visual field defects between POAG and NTG eyes were examined using logistic discriminant analysis. In the multiple regression analysis, total deviation (TD) of the 12 test points was graded and used as the dependent variable, and MD and the spherical equivalent refraction were the explanatory variables. In the logistic discrimination analysis, TD, MD, and refraction were covariants that determined the OAG subtypes. MAIN OUTCOME MEASURES TD values of the 12 central test points (C30-2 program). RESULTS Higher myopic refraction was significantly associated with more damage at a point just temporal and inferior to the fixation point in POAG eyes, whereas it was significantly associated with less damage at test points just temporal and superior to the fixation point in NTG eyes. After correcting for the influence of refraction, POAG eyes had significantly more damage at a test point just temporal and inferior to the fixation point, whereas NTG eyes had significantly more damage at those test points nasal and inferior to the fixation point. CONCLUSIONS High myopia constitutes a threat to the remaining lower cecocentral visual field and is one of the factors that interfere with the quality of vision in advanced OAG with high IOP but not low IOP.

Identification of Schlemm's Canal and Its Surrounding Tissues by Anterior Segment Fourier Domain Optical Coherence Tomography

PURPOSE To identify Schlemms canal (SC) and trabecular meshwork (TM) by anterior segment Fourier-domain optical coherence tomography (AS-FD-OCT) with histologic confirmation in enucleated human eyes and to quantitatively evaluate SC and TM in living human eyes. METHODS In enucleated human eyes, the imaging of the anterior chamber angle by AS-FD-OCT was performed before and after surgical expansion of SC with an injection of a viscoelastic material, followed by histologic examination. In 60 living human eyes, the agreement of identification of SC between examiners was evaluated with the Cohens κ values, and the lengths of SC and TM and the area of TM were measured on temporal and nasal sections of the AS-FD-OCT images. RESULTS In enucleated human eyes, SC was observed to be a thin, linear, lucent space in the AS-FD-OCT image obtained with the high-definition raster scan protocol, but not in those obtained with the bi-angle radial scan protocol. This space was enlarged after the SC expansion. In the histologic study, the SC was confirmed to be in the same position as in the AS-FD-OCT images. The κ values of observable SC in living human subjects were 0.92 or higher. The axial length of the SC averaged 347.2 ± 42.3 μm, TM length 466.9 ± 60.7 μm, and TM area 0.0671 ± 0.0058 mm². These measurements showed sufficient repeatability and reproducibility. CONCLUSIONS Using the high-definition images of the AS-FD-OCT, SC and its surrounding tissues were successfully observed in most of the living eyes and were quantitatively evaluated in a noninvasive manner.

Potential of the Pentacam in Screening for Primary Angle Closure and Primary Angle Closure Suspect

PurposeTo compare the Pentacam to ultrasound biomicroscopy (UBM) or gonioscopy in detecting eyes with primary angle closure (PAC), including PAC suspect and PAC glaucoma. Patients and MethodsIn 72 eyes of 39 Japanese with various anterior chamber angle (ACA) widths, the ACA, anterior chamber depth (ACD), and anterior chamber volume (ACV) were measured using the Pentacam, and the ACA was measured by UBM (ACAUBM). Correlations among these parameters and Shaffers grade based on gonioscopy in the corresponding quadrant were studied. The efficacy of the Pentacam in screening for PAC and PAC suspect was then analyzed by using receiving operator characteristic (ROC) curves and partition analysis. ResultsShaffers classification (grade 0 to 4) significantly correlated with each of the measurements using both screening devices (P<0.001), and most strongly correlated with ACAUBM. ACAUBM was also significantly correlated with each Pentacam parameter in all subjected eyes with angle widths of grades 0 to 4 (P<0.001), but not grade 2 or less (P>0.05). In screening eyes with PAC and PAC suspect with the Pentacam, the area under the ROC curve was largest (0.943) when ACV was used as the reference, and partition analysis showed that those eyes were most effectively partitioned with an ACD of 2.58 mm using the Pentacam, resulting in 100% sensitivity and 87.1% specificity. ConclusionsThe Pentacam has potential for safe, noncontact screening of eyes with PAC and PAC suspect, except for those with plateau iris configurations, based on measurements of the ACV and ACD, but not the ACA.

Use of calcium channel blockers for glaucoma

Calcium channel blockers (CCBs), which alter the intracellular calcium concentration by modifying calcium flux across cell membranes and affect various intracellular signaling processes, have been long and widely used to treat essential hypertension and certain types of cardiac diseases such as angina pectoris. Among five subtypes of calcium channels, only specific agents for L-type calcium channels have been used as therapeutics. Animal experiments have indicated that topical application of CCBs, especially verapamil, caused significant intraocular pressure (IOP) reductions, while ocular hypotensive effects in humans were not substantial. Although the results obtained for nifedipine and nimodipine were not always consistent, CCBs generally dilate isolated ocular vessels and increase ocular blood flow in experimental animals, normal humans, and patients with open-angle glaucoma (OAG). Several single-centered, hospital-based, prospective studies have suggested that nimodipine, brovincamine, and nilvadipine had beneficial effects on visual function not only in normal humans but also in patients with OAG, while the results of population-based and case-controlled studies were not always consistent with those obtained in hospital-based studies. In vitro studies showed that CCBs exerted neuroprotective effects on neurons undergoing apoptosis and necrosis. Although the neuroprotective effects of CCBs have been well documented in experimental cerebral ischemia models, no controlled studies have shown the clinical efficacy of CCBs in stroke or cerebral ischemia. Neuroprotective effects also were documented in retinal ganglion cells and photoreceptors in experimental animals. Some ophthalmic beta-adrenoceptor antagonists, especially betaxolol, interact with L-type calcium channels and show calcium channel-blocking activity, which may be partly responsible for the neuroprotective effects of these drugs reported in experimental animals. Based on the reported findings of CCBs and that the results of clinical studies in acute cerebral ischemia may not be directly applicable to a chronic neurodegenerative ocular disorder, such as OAG, CCBs deserve future study to investigate strategies that are additive or synergetic to ocular hypotensive therapy for OAG, especially in patients with lower IOP.

The 5-year incidence of bleb-related infection and its risk factors after filtering surgeries with adjunctive mitomycin C: collaborative bleb-related infection incidence and treatment study 2.

PURPOSE To report the 5-year incidence of bleb-related infection after mitomycin C-augmented glaucoma filtering surgery and to investigate the risk factors for infections. DESIGN Prospective, observational cohort study. PARTICIPANTS A total of 1098 eyes of 1098 glaucoma patients who had undergone mitomycin C-augmented trabeculectomy or trabeculectomy combined with phacoemulsification and intraocular lens implantation performed at 34 clinical centers. METHODS Patients were followed up at 6-month intervals for 5 years, with special attention given to bleb-related infections. The follow-up data were analyzed via Kaplan-Meier survival analysis and the Cox proportional hazards model. MAIN OUTCOME MEASURES Incidence of bleb-related infection over 5 years and risk factors for infections. RESULTS Of the 1098 eyes, a bleb-related infection developed in 21 eyes. Kaplan-Meier survival analysis revealed that the incidence of bleb-related infection was 2.2±0.5% (cumulative incidence ± standard error) at the 5-year follow-up for all cases, whereas it was 7.9±3.1% and 1.7±0.4% for cases with and without a history of bleb leakage, respectively (P = 0.000, log-rank test). When only eyes with a well-functioning bleb were counted, it was 3.9±1.0%. No differences were found between the trabeculectomy cases and the combined surgery cases (P = 0.398, log-rank test) or between cases with a fornix-based flap and those with a limbal-based flap (P = 0.651, log-rank test). The Cox model revealed that a history of bleb leakage and younger age were risk factors for infections. CONCLUSIONS The 5-year cumulative incidence of bleb-related infection was 2.2±0.5% in eyes treated with mitomycin C-augmented trabeculectomy or trabeculectomy combined with phacoemulsification and intraocular lens implantation in our prospective, multicenter study. Bleb leakage and younger age were the main risk factors for infections.

Cross-sectional Anatomic Configurations of Peripapillary Atrophy Evaluated with Spectral Domain-Optical Coherence Tomography

PURPOSE To evaluate the cross-sectional configurations of peripapillary atrophy (PPA)-alpha and -beta in ophthalmologically normal subjects using spectral domain-optical coherence tomography (SD-OCT). METHODS One hundred twenty normal subjects had a complete ophthalmic examination including axial length measurement, standard automated perimetry, fundus imaging with photography, and SD-OCT (3D OCT-1000; Topcon Inc., Tokyo, Japan). PPA-alpha and -beta were identified in color photographs of the optic disc. Cross-sectional B-mode images of the peripapillary retina and sclera, including PPA-alpha and -beta obtained with SD-OCT, were analyzed. RESULTS Of 120 normal eyes, 120 (100%) had PPA-alpha and 90 (75%) had PPA-beta. In OCT images of the peripapillary retina, the ganglion cell layer and the inner and outer plexiform layers were observed to end in a tapering fashion at the edge of the optic disc, whereas the retinal nerve fiber layer continued into the optic cup. The external limiting membrane (ELM), inner-outer segments (IS-OS), and retinal pigment epithelium(RPE)/Bruchs membrane complex were significantly more commonly absent before the optic disc edge within the PPA-beta compared with areas outside the PPA-beta (P < 0.0001). Specific findings in the peripapillary area including slope and step configurations of the scleral bed and hump- and wedge-shaped appearances of the RPE-Bruchs membrane complex were identified in 63 (52.5%), 6 (5.0%), 19 (15.8%), and 6 (5.0%) of 120 eyes, respectively. The presence of the step configuration was associated with myopia and longer axial length (P = 0.0014 and 0.0105, respectively). CONCLUSIONS The cross-sectional anatomic configurations of the peripapillary atrophy were evaluated by using SD-OCT. The termination of the retinal layers and configurations of the scleral bed in the peripapillary area varied among normal subjects.

Identifying areas of the visual field important for quality of life in patients with glaucoma.

Purpose The purpose of this study was to create a vision-related quality of life (VRQoL) prediction system to identify visual field (VF) test points associated with decreased VRQoL in patients with glaucoma. Method VRQoL score was surveyed in 164 patients with glaucoma using the ‘Sumi questionnaire’. A binocular VF was created from monocular VFs by using the integrated VF (IVF) method. VRQoL score was predicted using the ‘Random Forest’ method, based on visual acuity (VA) of better and worse eyes (better-eye and worse-eye VA) and total deviation (TD) values from the IVF. For comparison, VRQoL scores were regressed (linear regression) against: (i) mean of TD (IVF MD); (ii) better-eye VA; (iii) worse-eye VA; and (iv) IVF MD and better- and worse-eye VAs. The rank of importance of IVF test points was identified using the Random Forest method. Results The root mean of squared prediction error associated with the Random Forest method (0.30 to 1.97) was significantly smaller than those with linear regression models (0.34 to 3.38, p<0.05, ten-fold cross validation test). Worse-eye VA was the most important variable in all VRQoL tasks. In general, important VF test points were concentrated along the horizontal meridian. Particular areas of the IVF were important for different tasks: peripheral superior and inferior areas in the left hemifield for the ‘letters and sentences’ task, peripheral, mid-peripheral and para-central inferior regions for the ‘walking’ task, the peripheral superior region for the ‘going out’ task, and a broad scattered area across the IVF for the ‘dining’ task. Conclusion The VRQoL prediction model with the Random Forest method enables clinicians to better understand patients’ VRQoL based on standard clinical measurements of VA and VF.

Contributing factors for progression of visual field loss in normal-tension glaucoma patients with medical treatment.

Purpose:To investigate the prognostic factors responsible for the progression of visual field defects (VFDs) in patients with normal-tension glaucoma (NTG) treated with topical antiglaucoma medications. Patients and Methods:A total of 92 eyes in 92 NTG patients treated with only topical antiglaucoma medications for ≥5 years were retrospectively analyzed. To identify subfield-based prognostic factors, the central 30-degree visual field (Humphrey Field Analyzer) was divided into 6 subfields: upper and lower arcuate, paracentral, and cecocentral subfields. Factors related to subfield-based progression (age, refraction, mean intraocular pressure (IOP), IOP variability, central corneal thickness, and disc hemorrhage) were evaluated using a linear mixed model. Results:Ninety-two eyes in 92 NTG patients were included in this study. The mean observation period was 7.7±2.7 (5.0 to 15.5) years, and the estimated rate of change in the mean deviation value was −0.16±0.31 dB/y (P<0.001). A subfield-based linear mixed model analysis of the time course of changes in the mean of total deviation identified a greater extent of myopia as a significant positive prognostic factor for VFD progression in the upper paracentral area (P=0.016). The mean IOP, central corneal thickness, disc hemorrhage, age, and IOP variation showed no significant contribution in any of the subfields. Conclusions:The extent of myopia was found to be a significant positive prognostic factor for VFD progression in the upper paracentral subfield for non–high-myopic NTG eyes with an average IOP of 14.2 mm Hg under topical antiglaucoma medication.

Spectral-Domain Optical Coherence Tomography ofβ-zone Peripapillary Atrophy: Influence of Myopiaand Glaucoma

PURPOSE To investigate the influence of glaucoma and myopia on the cross-sectional configuration of the β-zone of peripapillary atrophy (PPA-β) using spectral-domain optical coherence tomography (SD-OCT). METHODS Cross-sectional B-scan images of PPA-β obtained with SD-OCT were evaluated in 100 eyes of 100 consecutive patients with POAG, regardless of intraocular pressure level, and in 100 eyes of 100 normal subjects. PPA bed configurations were classified, and associated factors were studied with multivariate analysis. RESULTS In 147 eyes with PPA-β (84 POAG and 63 normal eyes; P = 0.0012), the PPA bed was composed of straight (14 POAG and 27 normal eyes) or downward-curved (19 and 8 eyes) Bruchs membrane (BM) or of a downward-bending slope lacking BM (BM defect; 51 and 28 eyes). Multivariate analysis revealed that absence of POAG (odds ratio [OR], 0.36; P = 0.034) and less myopic refractive error (OR, 1.43; P = 0.009) were significantly associated with straight-BM-type, presence of POAG (OR, 5.74; P = 0.008) and less myopic refractive error (OR, 3.02; P < 0.001) with curved-BM-type, and myopic refractive error (OR, 0.34; P < 0.001) with BM-defect-type. Within the PPA-β region, all retinal layers except for the nerve fiber layer frequently disappeared before reaching the disc edge, showing no significant intergroup difference (P > 0.05) between POAG and normal eyes. CONCLUSIONS PPA bed configurations detected by SD-OCT were classified into three types. The lack of BM on the PPA bed was closely associated with myopia. The downward-curved appearance of BM may be related to the anatomic changes associated with glaucoma.