One-Year Efficacy and Safety of Combined Photorefractive Keratectomy and Accelerated Corneal Collagen Cross-Linking after Intacs SK Intracorneal Ring Segment Implantation in Moderate Keratoconus.

PURPOSE: To report one-year outcomes of a modified version of two-stage multimodal surgical protocol for moderate keratoconus which has been suggesting promising preliminary results. MATERIALS AND METHODS: 30 eyes of 25 patients with moderate keratoconus who exhibited visual complaints and/or disease progression were included for this retrospective case study. Approximately 3 months after implantation of intracorneal ring segment (Intacs SK™), a combination of corneal wavefront-guided transepithelial photorefractive keratectomy (CWG-transPRK, Schwind Amaris® 1050, and Schwind Sirius) and accelerated collagen cross-linking (accCXL, Avedro KXL™) was performed. Patients were examined for uncorrected and corrected distance visual acuity (UDVA; CDVA), keratometric power (K), corneal thickness, and corneal higher-order aberrations (HOAs) preoperatively and at postoperative 1, 3, 6, and 12 months. RESULTS: The median UDVA and mean CDVA were enhanced from 6/38 to 6/12 and from 6/19 to 6/7.5, respectively, through 12 months after CWG-transPRK/accCXL. The 12-month CDVA of all patients was better than 6/12 Snellen, and no subject lost one or more lines of CDVA. The magnitudes of both myopia and corneal steepness were decreased in turn by Intacs SK implantation and also by CWG-transPRK/accCXL, but the reduction in HOA was largely the result of CWG-transPRK/accCXL. The magnitude of corneal thinning stabilized within 3 months after CWG-transPRK/accCXL. CONCLUSION: This approach may allow patients with moderate keratoconus to obtain satisfactory vision without the need for contact lens wear. This surgery appeared to be effective and safe through 1 year of follow-up.

A Two-Step Neural Dialog State Tracker for Task-Oriented Dialog Processing.

Dialog state tracking in a spoken dialog system is the task that tracks the flow of a dialog and identifies accurately what a user wants from the utterance. Since the success of a dialog is influenced by the ability of the system to catch the requirements of the user, accurate state tracking is important for spoken dialog systems. This paper proposes a two-step neural dialog state tracker which is composed of an informativeness classifier and a neural tracker. The informativeness classifier which is implemented by a CNN first filters out noninformative utterances in a dialog. Then, the neural tracker estimates dialog states from the remaining informative utterances. The tracker adopts the attention mechanism and the hierarchical softmax for its performance and fast training. To prove the effectiveness of the proposed model, we do experiments on dialog state tracking in the human-human task-oriented dialogs with the standard DSTC4 data set. Our experimental results prove the effectiveness of the proposed model by showing that the proposed model outperforms the neural trackers without the informativeness classifier, the attention mechanism, or the hierarchical softmax.

Enhancement of refractive outcomes of small-incision lenticule extraction via tear-film control.

PURPOSE: To suggest that tear film is a refractive outcome predictor in small-incision lenticule extraction (SMILE) for myopia and describe methods of controlling the tear film and its effects on refractive outcomes. METHODS: In this retrospective case-control study, the tear film was kept clear and appropriate in amount during tear-film-controlled SMILE (TFC-SMILE). In contrast, no special care to the tear film was given in direct-docking SMILE (DD-SMILE). Both procedures were performed by the same experienced surgeon, using the same surgical parameters, over defined periods. In select cases, scanning electron microscopy (SEM) of the lenticule and surgical videos of opaque bubble layers (OBLs) were obtained and compared. RESULTS: Forty-one eyes had DD-SMILE and 55 eyes had TFC-SMILE. Multivariate analysis showed that TFC-SMILE and the patient's age were significant predictors of refractive outcomes. The refractive predictability of TFC-SMILE was better than that of DD-SMILE, and under-correction of high myopia was evident in the latter patients. The predictive errors of DD-SMILE became more myopic and variable during 1 year than those of TFC-SMILE. The lenticular surface on SEM was more serrated in DD-SMILE. Severe OBLs were evident in four cases of DD-SMILE and the OBL pattern was sporadic at the anterior surface of the lenticule. CONCLUSIONS: The presence of a clear and appropriate tear film in SMILE enhanced predictability, minimized variability, and ensured stability of refractive outcomes. An uncontrolled tear film might render cutting imprecise and trigger severe OBL formation. TFC-SMILE had more predictable results than DD-SMILE.

Automated extraction of Biomarker information from pathology reports.

BACKGROUND: Pathology reports are written in free-text form, which precludes efficient data gathering. We aimed to overcome this limitation and design an automated system for extracting biomarker profiles from accumulated pathology reports. METHODS: We designed a new data model for representing biomarker knowledge. The automated system parses immunohistochemistry reports based on a "slide paragraph" unit defined as a set of immunohistochemistry findings obtained for the same tissue slide. Pathology reports are parsed using context-free grammar for immunohistochemistry, and using a tree-like structure for surgical pathology. The performance of the approach was validated on manually annotated pathology reports of 100 randomly selected patients managed at Seoul National University Hospital. RESULTS: High F-scores were obtained for parsing biomarker name and corresponding test results (0.999 and 0.998, respectively) from the immunohistochemistry reports, compared to relatively poor performance for parsing surgical pathology findings. However, applying the proposed approach to our single-center dataset revealed information on 221 unique biomarkers, which represents a richer result than biomarker profiles obtained based on the published literature. Owing to the data representation model, the proposed approach can associate biomarker profiles extracted from an immunohistochemistry report with corresponding pathology findings listed in one or more surgical pathology reports. Term variations are resolved by normalization to corresponding preferred terms determined by expanded dictionary look-up and text similarity-based search. CONCLUSIONS: Our proposed approach for biomarker data extraction addresses key limitations regarding data representation and can handle reports prepared in the clinical setting, which often contain incomplete sentences, typographical errors, and inconsistent formatting.

A Neural Machine Translation Model for Arabic Dialects That Utilises Multitask Learning (MTL).

In this research article, we study the problem of employing a neural machine translation model to translate Arabic dialects to modern standard Arabic. The proposed solution of the neural machine translation model is prompted by the recurrent neural network-based encoder-decoder neural machine translation model that has been proposed recently, which generalizes machine translation as sequence learning problems. We propose the development of a multiytask learning (MTL) model which shares one decoder among language pairs, and every source language has a separate encoder. The proposed model can be applied to limited volumes of data as well as extensive amounts of data. Experiments carried out have shown that the proposed MTL model can ensure a higher quality of translation when compared to the individually learned model.

A Natural Language Interface Concordant with a Knowledge Base.

The discordance between expressions interpretable by a natural language interface (NLI) system and those answerable by a knowledge base is a critical problem in the field of NLIs. In order to solve this discordance problem, this paper proposes a method to translate natural language questions into formal queries that can be generated from a graph-based knowledge base. The proposed method considers a subgraph of a knowledge base as a formal query. Thus, all formal queries corresponding to a concept or a predicate in the knowledge base can be generated prior to query time and all possible natural language expressions corresponding to each formal query can also be collected in advance. A natural language expression has a one-to-one mapping with a formal query. Hence, a natural language question is translated into a formal query by matching the question with the most appropriate natural language expression. If the confidence of this matching is not sufficiently high the proposed method rejects the question and does not answer it. Multipredicate queries are processed by regarding them as a set of collected expressions. The experimental results show that the proposed method thoroughly handles answerable questions from the knowledge base and rejects unanswerable ones effectively.

Learning word sense disambiguation in biomedical text with difference between training and test distributions.

Word Sense Disambiguation methods based on machine learning techniques with lexical features suffer from the discordance between distributions of the training and test documents, due to the diversity of lexical space. To tackle this problem, this paper proposes Support Vector Machines with Example-wise Weights. In this method, the training distribution is matched with the test distribution by weighting training examples according to their similarity to all test data. The experimental results show the distribution change between the training and test data is actually recognised and the proposed method which considers this change in its training phase outperforms ordinary SVMs.

Hydrophilic acrylic intraocular lens optic opacification in a diabetic patient.

PURPOSE: To report clinicopathologic and ultrastructural feature of one opacified hydrophilic acrylic intraocular lens (IOL) explanted from a diabetic patient. METHODS: A 48-year-old man underwent trans pars plana vitrectomy and phacoemulsification with implantation of a hydrophilic acrylic lens OS in November 2008. The patient complained of a marked decrease in visual acuity in May 2009 as a result of a milky opalescence of the IOL. Intraocular lens explantation and exchange were performed in August 2009, and the explanted IOL was submitted to our center for detailed pathologic, histochemical and ultrastructural evaluation. It was stained by the von Kossa method for calcium, and also underwent scanning electron microscopy and energy dispersive radiograph spectroscopy to ascertain the nature of the deposits leading to opacification. RESULTS: Opacification of the IOL was found to be the cause of the decreased visual acuity. The opacification involved only the IOL optic, and the haptics was clear. Histochemical and ultrastructural analyses revealed that the opacity was caused by deposition of calcium and phosphate within the lens optic. CONCLUSION: We believe this report of calcification of the Akreos(®) MI-60 IOL is of clinicopathological importance. Long-term follow-up of diabetic patients implanted with this IOL should be maintained by surgeons and manufacturers.

Assessment of narrow angles by gonioscopy, Van Herick method and anterior segment optical coherence tomography.

PURPOSE: To evaluate anterior chamber (AC) angles using gonioscopy, Van Herick technique and anterior segment optical coherence tomography (AS-OCT). METHODS: One hundred forty-eight consecutive subjects were enrolled. The agreement between any two of three diagnostic methods, gonioscopy, AS-OCT and Van Herick, was calculated in narrow-angle patients. The area under receiver-operating characteristic curves (AUC) for discriminating between narrow and open angles determined by gonioscopy was calculated in all participants for AS-OCT parameter angle opening distance (AOD), angle recess area, trabecular iris surface area and anterior chamber depth (ACD). As a subgroup analysis, capability of AS-OCT parameters for detecting angle closure defined by AS-OCT was assessed in narrow-angle patients. RESULTS: The agreement between the Van Herick method and gonioscopy in detecting angle closure was excellent in narrow angles (κ = 0.80, temporal; κ = 0.82, nasal). However, agreement between gonioscopy and AS-OCT and between the Van Herick method and AS-OCT was poor (κ = 0.11-0.16). Discrimination capability of AS-OCT parameters between open and narrow angles determined by gonioscopy was excellent for all AS-OCT parameters (AUC, temporal: AOD500 = 0.96, nasal: AOD500 = 0.99). The AUCs for detecting angle closure defined by AS-OCT image in narrow angle subjects was good for all AS-OCT parameters (AUC, 0.80-0.94) except for ACD (temporal: ACD = 0.70, nasal: ACD = 0.63). CONCLUSION: Assessment of narrow angles by gonioscopy and the Van Herick technique showed good agreement, but both measurements revealed poor agreement with AS-OCT. The angle closure detection capability of AS-OCT parameters was excellent; however, it was slightly lower in ACD.

Learning curve for a laparoscopic appendectomy by a surgical trainee.

PURPOSE: The laparoscopic appendectomy has been a basic part of the principal of a more complex laparoscopic technique for the surgical trainee. As the number of laparoscopic appendectomies performed by surgical trainees has increased, we are trying to check the stability of, which is controversial, and the learning curve associated with a laparoscopic appendectomy. METHODS: We studied the demographics, histologic diagnoses, operative time, the number of complicated cases, and hospital duration of one hundred and three patients who underwent an open appendectomy (group A, 53) or a laparoscopic appendectomy (group B, 50) retrospectively through a review of their medical records. The learning curve for the laparoscopic appendectomy was established through the moving average and ANOVA methods. RESULTS: There were no differences in the operative times (A, 64.15 ± 29.88 minutes; B, 58.2 ± 20.72 minutes; P-value, 0.225) and complications (A, 11%; B, 6%; P-value, 0.34) between group A and group B. Group B was divided into group C who underwent the operation in the early period (before the learning curve) and group D who underwent the operation in the later period (after the learning curve). The average operative time for group C was 66.83 ± 21.55 minutes, but it was 45.25 ± 10.19 minutes for group D (P-value < 0.0001). Although this difference was statistically significant, no significant difference in the complication rate was observed between the two groups. CONCLUSION: A laparoscopic appendectomy, compared with an open appendectomy, performed by a surgical trainee is safe. In this study, the learning curve for a laparoscopic appendectomy was thirty cases.

Comparison of retinal nerve fibre layer thickness measurements calculated by the optic nerve head map (NHM4) and RNFL3.45 modes of spectral-domain optical coherence tomography (RTVue-100).

AIM: To evaluate and compare retinal nerve fibre layer (RNFL) thickness measured by direct scanning (RNFL3.45 mode) and re-sampling from datasets (NHM4 mode) of RTVue-100 optical coherence tomography (OCT). METHODS: Thirty-six healthy subjects and 76 subjects with glaucoma were imaged with Stratus OCT (fast RNFL mode, RNFL3) and RTVue-100 OCT (NHM4 (RNFL1) and RNFL3.45 (RNFL2) modes). Measurement reproducibility was assessed in NHM4 and RNFL3.45 modes of RTVue-100 OCT (intraclass correlation coefficient (ICC)). Agreement between different RNFL measurements was analysed by Bland-Altman plot. The areas under the receiver operating characteristic (ROC) curves (AUCs) for discrimination between healthy and glaucoma were compared between the different RNFL measurements. RESULTS: Both NHM4 and RNFL3.45 modes showed excellent measurement reproducibilities (ICC 0.831-0.978). RNFL thicknesses by two different modes of the RTVue-100 OCT, and by the Stratus OCT, were correlated in all sectors, including average. There was no significant difference between RNFL1 and RNFL2 data. However, RNFL thickness in glaucomatous eyes by the RTVue-100 OCT was significantly greater than that measured by Stratus OCT. RNFL thicknesses determined by the two different modes of RTVue-100 OCT were in excellent agreement (95% limits of agreement -6.53 to 6.95 mum). All three RNFL measurements showed good glaucoma discrimination ability (AUC = RNFL1 0.970, RNFL2 0.962, RNFL3 0.971). CONCLUSIONS: RNFL thickness determined by direct scanning and re-sampling from datasets of RTVue-100 OCT were in good agreement. However, both measurements in glaucomatous subjects were significantly different from those with the Stratus OCT. Those findings should be considered when a patient is followed-up using different types of OCT.

Hit integration for identifying optimal spaced seeds.

BACKGROUND: Introduction of spaced speeds opened a way of sensitivity improvement in homology search without loss of search speed. Since then, the efforts of finding optimal seed which maximizes the sensitivity have been continued today. The sensitivity of a seed is generally computed by its hit probability. However, the limitation of hit probability is that it computes the sensitivity only at a specific similarity level while homologous regions usually distributed in various similarity levels. As a result, the optimal seed found by hit probability is not actually optimal for various similarity levels. Therefore, a new measure of seed sensitivity is required to recommend seeds that are robust to various similarity levels. RESULTS: We propose a new probability model of sensitivity hit integration which covers a range of similarity levels of homologous regions. A novel algorithm of computing hit integration is proposed which is based on integration of hit probabilities at a range of similarity levels. We also prove that hit integration is computable by expressing the integral part of hit integration as a recursive formula which can be easily solved by dynamic programming. The experimental results for biological data show that hit integration reveals the seeds more optimal than those by PatternHunter. CONCLUSION: The presented model is a more general model to estimate sensitivity than hit probability by relaxing similarity level. We propose a novel algorithm which directly computes the sensitivity at a range of similarity levels.

Macular and peripapillary retinal nerve fiber layer measurements by spectral domain optical coherence tomography in normal-tension glaucoma.

PURPOSE: To evaluate and compare the glaucoma discrimination ability of macular inner retinal layer (MIRL) thickness with that of peripapillary retinal nerve fiber layer (pRNFL) thickness measured by spectral-domain optical coherence tomography (RTVue-100; Optovue Inc, Fremont, CA) in patients with normal-tension glaucoma (NTG). METHODS: Sixty-five healthy subjects and 102 with NTG were enrolled. MIRL thickness provided by a ganglion cell complex (GCC) scan and two RNFL thicknesses measured by the NHM4 (RNFL1) and RNFL 3.45 (RNFL2) modes of the RTVue-100 system were analyzed. The areas under the receiver operating characteristic curves (AUCs) of MIRL and pRNFL thicknesses for discriminating patients with NTG from control subjects were determined. The AUCs were compared between patients with central visual field (VF) defects (VF; 10 degrees from fixation). RESULTS: The average MIRL thickness showed a strong correlation with both RNFL1 and -2 thicknesses (R(2) = 0.773, 0.774, both P < 0.0001). The AUCs for average MIRL, RNFL1, and RNFL2 thicknesses were not significantly different at 0.945, 0.973, and 0.976, respectively. However, the AUCs of the average and superior MIRL thicknesses were significantly less than that of the pRNFL thickness in eyes with moderate-to-advanced glaucoma and eyes with peripheral VF defects. CONCLUSIONS: The average MIRL thickness showed a strong correlation with pRNFL thickness, because patients with NTG at an early stage showed paracentral VF defects near the fixation point. MIRL thickness showed glaucoma discrimination ability comparable to that of pRNFL thickness in patients with NTG with early VF defects. In eyes with advanced or peripheral VF defect, pRNFL measurement showed a better glaucoma diagnostic ability than did MIRL measurement.

An empirical study of choosing efficient discriminative seeds for oligonucleotide design.

BACKGROUND: Oligonucleotide design is known as a time-consuming work in bioinformatics. In order to accelerate and be efficient the oligonucleotide design process, one of widely used approach is the prescreening unreliable regions using a hashing (or seeding) algorithm. Since the seeding algorithm is originally proposed to increase sensitivity for local alignment, the specificity should be considered as well as the sensitivity for the oligonucleotide design problem. However, a measure of evaluating the seeds regarding how adequate and efficient they are in the oligo design is not yet proposed. Here, we propose novel measures of evaluating the seeding algorithms based on the discriminability and the efficiency. RESULTS: To evaluate the proposed measures, we examine five seeding algorithms in oligonucleotide design. We carried out a series of experiments to compare the seeding algorithms. As the result, the spaced seed is recorded as the most efficient discriminative seed for oligo design. The performance of transition-constrained seed is slightly lower than the spaced seed. Because BLAT seeding algorithm and Vector seeding algorithm give poor scores in specificity and efficiency, we conclude that these algorithms are not adequate to design oligos. Consequently, we recommend spaced seeds or transition-constrained seeds with 15 approximately 18 weight in order to design oligos with the length of 50 mer. The empirical experiments in real biological data reveal that the recommended seeds show consequently good performance. We also propose a software package which enables the users to get the adequate seeds under their own experimental conditions. CONCLUSION: Our study is valuable to the two points. One is that our study can be applied to the oligo design programs in order to improve the performance by suggesting the experiment-specific seeds. The other is that our study is useful to improve the performance of the mapping assembly in the field of Next-Generation Sequencing. Our proposed measures are originally designed to be used for oligo design but we expect that our study will be helpful to the other genomic tasks.

Comparison of glaucoma diagnostic Capabilities of Cirrus HD and Stratus optical coherence tomography.

OBJECTIVE: To compare the glaucoma diagnostic capabilities offered by Stratus and Cirrus spectral-domain optical coherence tomography (OCT). METHODS: One hundred subjects with glaucoma and 74 healthy subjects were tested by Stratus and Cirrus OCT. Areas under the receiver operating characteristic curves (AUCs) of average, 4-quadrant, and 12-sector retinal nerve fiber layer thicknesses and sensitivities at fixed specificities (80% and 90%) were compared when the 2 OCT modalities were used to evaluate patients with early or moderate to advanced glaucoma. Likelihood ratios using normative classifications were reported. RESULTS: Overall, both OCT instruments showed similar glaucoma discrimination capability in average retinal nerve fiber layer thickness (AUC, 0.953 [Cirrus] vs 0.934 [Stratus]; P = .15). Cirrus OCT displayed significantly higher AUCs in the average, inferior, temporal, and superior quadrants and 7-o'clock measurements in early stages of glaucoma. The between-OCT instrument AUCs did not differ significantly in moderate to advanced stages. Abnormal results for both OCT instruments, after comparison with their normative databases, were associated with high likelihood ratios. CONCLUSIONS: In our series, the Cirrus OCT showed better glaucoma discrimination capability than Stratus OCT in early stages of glaucoma. Our findings suggest that spectral-domain technology of OCT may offer an improved capability of early-stage glaucoma detection.

Structural and functional relationships in glaucoma using standard automated perimetry and the Humphrey Matrix.

PURPOSE: To evaluate and compare correlations between structural and functional loss in glaucoma as assessed by optical coherence tomography (OCT), scanning laser polarimetry (GDx VCC, as this was the model used in this study), standard automated perimetry (SAP), and the Humphrey Matrix (Matrix). METHODS: Ninety glaucomatous eyes identified with SAP and 112 eyes diagnosed using Matrix were independently classified into six subgroups, either S1/M1 (MD>-6dB), S2/M2 (-12

Glaucoma diagnostic performance of humphrey matrix and standard automated perimetry.

PURPOSE: To evaluate and compare the performance of Humphrey Matrix perimetry (Matrix) and standard automated perimetry (SAP) for glaucoma discrimination. METHODS: Forty-seven healthy and 68 glaucomatous subjects were included in this study. Glaucoma was defined as having a glaucomatous optic disc and a nerve fiber indicator (NFI) GDx VCC scanning laser polarimetry score of >40. Glaucomatous subjects were classified into two groups, early (40 < NFI < or = 50) and moderate to advanced (NFI > 50). The number of clusters on Matrix and SAP pattern deviation maps were estimated and scored. Areas under the receiver operating characteristic curves (AUCs) of the cluster scores were calculated for early and moderate to advanced stages of glaucoma and compared between Matrix and SAP. RESULTS: Among 68 glaucomatous subjects, 24 eyes were classified as having early and 44 eyes as having moderate to advanced glaucoma. The overall AUC of the Matrix cluster score was comparable to that of SAP (0.857, 0.881, P = 0.538). The AUC of the cluster score did not reveal statistically significant differences between Matrix and SAP for either early or moderate to advanced stages of glaucoma (P = 0.831, 0.237). CONCLUSION: Both Matrix and SAP showed good diagnostic performance with glaucoma defined as structural loss. Matrix and SAP data showed similar discrimination capability for different stages of glaucoma determined by cluster analysis.

Twenty-four hour ocular perfusion pressure fluctuation and risk of normal-tension glaucoma progression.

PURPOSE: To investigate the relationship between clinical factors including 24-hour mean ocular perfusion pressure (MOPP, (2/3) x mean arterial pressure [MAP] - intraocular pressure [IOP]) and visual field (VF) progression in eyes with medically treated normal-tension glaucoma (NTG). METHODS: One hundred one eyes of 101 NTG patients followed up for more than 4 years (mean follow-up, 6.2 years +/- 12.1 months) were included after retrospective chart review. Several clinical factors including demographic, systemic, ocular risk factors, and 24-hour MOPP were explored for associations with decreasing VF. Kaplan-Meier analyses were performed to compare outcomes with reference to four risk factors (age, myopia, and elevated MAP and MOPP fluctuation) for VF deterioration. Hazard ratios (HRs) for the association between potential risk factors and glaucoma progression were obtained using Cox proportional hazards models. RESULTS: Overall VF progression was detected in 29 (28.7%) eyes. There were significant differences between progressors and nonprogressors in nocturnal MAP and MOPP fluctuations (both P < 0.0001), 24-hour MAP, and MOPP fluctuations (both P < 0.0001), initial mean deviation (P = 0.0034), and pattern standard deviation (PSD) score (P < 0.0001). Both elevated 24-hour MAP and MOPP fluctuations were associated with greater VF progression probabilities based on Kaplan-Meier analyses. Among all risk factors investigated, the Cox proportional hazards model indicated that VF progression was significantly associated with 24-hour MOPP fluctuation and initial PSD score. CONCLUSIONS: Clinical factors other than IOP were associated with VF progression in our series of medically treated NTG eyes. Twenty-four-hour MOPP fluctuation was the most consistent prognostic factor for glaucoma progression.

Comparison between dynamic contour tonometry and Goldmann applanation tonometry.

PURPOSE: To compare the intraocular pressures (IOPs) measured by dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT), and to investigate the association of IOPs on eyes of varying central corneal thickness (CCT). METHODS: In this prospective study, 451 eyes of 233 subjects were enrolled. IOPs were measured by GAT and DCT. CCT was measured three times and the average was calculated. Each eye was classified into one of three groups according to CCT: low CCT (group A, CCT<520 microm, n=146); normal CCT (group B, 520 microm550 microm, n=142). In each group, we investigated the association of CCT with IOP measurement by GAT and DCT. RESULTS: The IOPs measured by GAT and DCT were significantly associated for all eyes (R=0.853, p<0.001, Pearson correlation). CCT was related with both IOP measurement by GAT and DCT with statistical significance (mixed effect model, p<0.001). However, subgroup analysis showed that CCT affected IOP measured by GAT for groups B and C, whereas it affected IOP measured by DCT only for group C. CONCLUSIONS: IOP measured by DCT was not affected by CCT in eyes with low to normal CCT, whereas this measurement was affected in eyes of high CCT range. CCT may have less effect on IOP measurements using DCT than those obtained by GAT, within a specified range of CCT.

Twenty-four hour blood pressure pattern in patients with normal tension glaucoma in the habitual position.

PURPOSE: To investigate the relationship between blood pressure (BP) parameters in the habitual position and glaucomatous damage at initial presentation in patients with untreated normal tension glaucoma (NTG). METHODS: Fifty-four eyes from 54 subjects diagnosed with NTG were consecutively enrolled. BP was measured with an automated ambulatory monitoring device in the habitual position during 24-hour in-hospitalization. Patients were classified into three groups: non-dippers, dippers, and over-dippers. corresponded to the degree of reduction in their nocturnal mean arterial pressure (MAP) compared with their diurnal MAP. Regression models were used to evaluate potential risk factors, including: age, pre-admission office intraocular pressure (IOP), central corneal thickness (CCT), and BP parameters. Functional outcome variables for glaucomatous damage included mean deviation (MD) and pattern standard deviation (PSD) on a Humphrey field analyzer (HFA). Anatomic outcome variables were TSNIT score (temporal, superior, nasal, inferior, and temporal) average, superior average, inferior average, and nerve fiber indicator (NFI) score on scanning laser polarimetry with variable corneal compensation (SLP-VCC; GDx-VCC). RESULTS: Marked systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP fluctuation were noted in the over-dipper group (p<0.05). A linear regression analysis model revealed that nocturnal trough DBP and MAP, average nocturnal SBP, and MAP were all significantly associated with a decreased average TSNIT score and an increased NFI score. CONCLUSIONS: Nocturnal BP reduction estimated in the habitual position was associated with structural damage in eyes with NTG. This finding may suggest systemic vascular etiology of NTG development associated with nocturnal BP reduction.