Efficacy of Intra-Articular Hypertonic Dextrose (Prolotherapy) for Knee Osteoarthritis: A Randomized Controlled Trial.

PURPOSE: To test the efficacy of intra-articular hypertonic dextrose prolotherapy (DPT) vs normal saline (NS) injection for knee osteoarthritis (KOA). METHODS: A single-center, parallel-group, blinded, randomized controlled trial was conducted at a university primary care clinic in Hong Kong. Patients with KOA (n = 76) were randomly allocated (1:1) to DPT or NS groups for injections at weeks 0, 4, 8, and 16. The primary outcome was the Western Ontario McMaster University Osteoarthritis Index (WOMAC; 0-100 points) pain score. The secondary outcomes were the WOMAC composite, function and stiffness scores; objectively assessed physical function test results; visual analogue scale (VAS) for knee pain; and EuroQol-5D score. All outcomes were evaluated at baseline and at 16, 26, and 52 weeks using linear mixed model. RESULTS: Randomization produced similar groups. The WOMAC pain score at 52 weeks showed a difference-in-difference estimate of -10.34 (95% CI, -19.20 to -1.49, P = 0.022) points. A similar favorable effect was shown on the difference-in-difference estimate on WOMAC function score of -9.55 (95% CI, -17.72 to -1.39, P = 0.022), WOMAC composite score of -9.65 (95% CI, -17.77 to -1.53, P = 0.020), VAS pain intensity score of -10.98 (95% CI, -21.36 to -0.61, P = 0.038), and EuroQol-5D VAS score of 8.64 (95% CI, 1.36 to 5.92, P = 0.020). No adverse events were reported. CONCLUSION: Intra-articular dextrose prolotherapy injections reduced pain, improved function and quality of life in patients with KOA compared with blinded saline injections. The procedure is straightforward and safe; the adherence and satisfaction were high.

Efficacy of intra-articular hypertonic dextrose prolotherapy versus normal saline for knee osteoarthritis: a protocol for a triple-blinded randomized controlled trial.

BACKGROUND: Knee Osteoarthritis (KOA) is a very common condition with prevalence rising with age. It is a major contributor to global disability and has a large socioeconomic burden worldwide. Conservative therapies have marginal effectiveness, and surgery is reserved for severe symptomatic KOA. Dextrose Prolotherapy (DPT) is an evidence-based injection-based therapy for chronic musculoskeletal conditions including KOA. The standard "whole joint" injection method includes intra-articular injection and multiple extra-articular injections at soft tissue bony attachments. The procedure is painful and requires intensive procedural training often unavailable in conventional medical education, which potentially limits access. Intra-articular injection offers the possibility of a less painful, more accessible treatment. The aim of this project is to assess the clinical efficacy of intra-articular injection of DPT versus normal saline (NS) for KOA. METHOD: Seventy-six participants with KOA will be recruited from the community. We will conduct a single center, parallel group, superiority randomized controlled trial comparing DPT and NS injections, with blinding of physician, participants, outcome assessors and statisticians. Each group will receive injections at week 0, 4, 8 and 16. The primary outcome will be the Western Ontario McMaster University Osteoarthritis Index pain scale (WOMAC), and secondary outcomes include WOMAC composite score, the WOMAC function and stiffness subscale, the Visual Analogue Score of pain, objective physical function tests (the 30 s chair stand, 40- m fast paced walk test, the Timed up and go test) and the EuroQol-5D (EQ-5D). All outcomes will be evaluated at baseline, and 16, 26 and 52 weeks. All analyses will be conducted on an intention-to-treat basis using linear mixed regression models. DISCUSSION: This paper presents the rationale, design, method and operational aspects of the trial. The findings will determine whether IA DPT, an inexpensive and simple injection, is a safe and effective non-surgical option for KOA. The results can be translated directly to clinical practice, with potentially substantial impact to patient care. TRIAL REGISTRATION: The trial ( ChiCTR-IPC-15006617 ) is registered under Chinese Clinical Trials Registry on 17th June 2015.

Potential therapeutic efficacy of photodynamic therapy on female hormonal-dependent cancers in a hormonal simulated microenvironment.

BACKGROUND: Photodynamic Therapy (PDT) is a clinically approved cancer treatment. Sex hormones, the key drivers for the development of female hormonal dependent cancers, might affect cancer treatment. There are seldom studies to evaluate the effect of sex hormones mimicked the menstrual cycle on the PDT mediated by prodrug 5-aminolevulinic acid (ALA) and its ester derivatives to the hormonal dependent cancers. AIMS: To evaluate the efficacy of sex hormones on Hexyl-ALA-PDT in hormonal dependent cancers and the effect of the sex hormones on heme biosynthetic pathway. METHODS: Cell culture system that mimicked the fluctuation of sex hormones 17ß-estradiol (E2) and progesterone (PG) in the menstrual cycle was developed. Two pairs of hormonal-independent and hormonal dependent uterine sarcoma and breast cancer cell lines were used as cell models. Hexyl-ALA induced PpIX production and intracellular localization were examined. Key enzymes for PpIX synthesis were analysed. Hexyl-ALA-PDT mediated phototoxicity was evaluated. RESULTS: The PpIX generation was increased in the hormonal-dependent cells (28-50 %) when cultured in the hormonal microenvironment with long incubation of Hexyl-ALA for 15 and 24 h compared to that cultured without hormones; whereas only slight difference in PpIX generation in their hormonal-independent counterpart. The PpIX generation was in a time-dependent manner. The CPOX, PPOX and FECH expressions were significantly enhanced by Hexyl-ALA-PDT in uterine sarcoma cells in hormonal microenvironment. Hexyl-ALA-PDT triggered significant increase of PPOX expression in breast cancer cells in hormonal microenvironment. The Hexyl-ALA-PDT phototoxicity was enhanced by 18-40 % in cells cultured in the hormonal system in a dose-dependent manner. CONCLUSION: The PpIX generation and the efficacy of Hexyl-ALA-PDT in both uterine sarcoma and breast cancer cells was significantly enhanced by the sex hormones via cultured in the hormonal microenvironment.

Integrating Demographics and Imaging Features for Various Stages of Dementia Classification: Feed Forward Neural Network Multi-Class Approach.

BACKGROUND: MRI magnetization-prepared rapid acquisition (MPRAGE) is an easily available imaging modality for dementia diagnosis. Previous studies suggested that volumetric analysis plays a crucial role in various stages of dementia classification. In this study, volumetry, radiomics and demographics were integrated as inputs to develop an artificial intelligence model for various stages, including Alzheimer's disease (AD), mild cognitive decline (MCI) and cognitive normal (CN) dementia classifications. METHOD: The Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset was separated into training and testing groups, and the Open Access Series of Imaging Studies (OASIS) dataset was used as the second testing group. The MRI MPRAGE image was reoriented via statistical parametric mapping (SPM12). Freesurfer was employed for brain segmentation, and 45 regional brain volumes were retrieved. The 3D Slicer software was employed for 107 radiomics feature extractions from within the whole brain. Data on patient demographics were collected from the datasets. The feed-forward neural network (FFNN) and the other most common artificial intelligence algorithms, including support vector machine (SVM), ensemble classifier (EC) and decision tree (DT), were used to build the models using various features. RESULTS: The integration of brain regional volumes, radiomics and patient demographics attained the highest overall accuracy at 76.57% and 73.14% in ADNI and OASIS testing, respectively. The subclass accuracies in MCI, AD and CN were 78.29%, 89.71% and 85.14%, respectively, in ADNI testing, as well as 74.86%, 88% and 83.43% in OASIS testing. Balanced sensitivity and specificity were obtained for all subclass classifications in MCI, AD and CN. CONCLUSION: The FFNN yielded good overall accuracy for MCI, AD and CN categorization, with balanced subclass accuracy, sensitivity and specificity. The proposed FFNN model is simple, and it may support the triage of patients for further confirmation of the diagnosis.

AI Deployment on GBM Diagnosis: A Novel Approach to Analyze Histopathological Images Using Image Feature-Based Analysis.

BACKGROUND: Glioblastoma (GBM) is one of the most common malignant primary brain tumors, which accounts for 60-70% of all gliomas. Conventional diagnosis and the decision of post-operation treatment plan for glioblastoma is mainly based on the feature-based qualitative analysis of hematoxylin and eosin-stained (H&E) histopathological slides by both an experienced medical technologist and a pathologist. The recent development of digital whole slide scanners makes AI-based histopathological image analysis feasible and helps to diagnose cancer by accurately counting cell types and/or quantitative analysis. However, the technology available for digital slide image analysis is still very limited. This study aimed to build an image feature-based computer model using histopathology whole slide images to differentiate patients with glioblastoma (GBM) from healthy control (HC). METHOD: Two independent cohorts of patients were used. The first cohort was composed of 262 GBM patients of the Cancer Genome Atlas Glioblastoma Multiform Collection (TCGA-GBM) dataset from the cancer imaging archive (TCIA) database. The second cohort was composed of 60 GBM patients collected from a local hospital. Also, a group of 60 participants with no known brain disease were collected. All the H&E slides were collected. Thirty-three image features (22 GLCM and 11 GLRLM) were retrieved from the tumor volume delineated by medical technologist on H&E slides. Five machine-learning algorithms including decision-tree (DT), extreme-boost (EB), support vector machine (SVM), random forest (RF), and linear model (LM) were used to build five models using the image features extracted from the first cohort of patients. Models built were deployed using the selected key image features for GBM diagnosis from the second cohort (local patients) as model testing, to identify and verify key image features for GBM diagnosis. RESULTS: All five machine learning algorithms demonstrated excellent performance in GBM diagnosis and achieved an overall accuracy of 100% in the training and validation stage. A total of 12 GLCM and 3 GLRLM image features were identified and they showed a significant difference between the normal and the GBM image. However, only the SVM model maintained its excellent performance in the deployment of the models using the independent local cohort, with an accuracy of 93.5%, sensitivity of 86.95%, and specificity of 99.73%. CONCLUSION: In this study, we have identified 12 GLCM and 3 GLRLM image features which can aid the GBM diagnosis. Among the five models built, the SVM model proposed in this study demonstrated excellent accuracy with very good sensitivity and specificity. It could potentially be used for GBM diagnosis and future clinical application.

Impact of Effective Intravesical Therapies on Quality of Life in Patients with Non-Muscle Invasive Bladder Cancer: A Systematic Review.

BACKGROUND: Conventional and newly emerged intravesical modalities have demonstrated prophylactic effectiveness that may improve quality of life (QoL) in non-muscle invasive bladder cancer. The purpose of this study is to analyze existing QoL evidence in patients receiving any form of intravesical therapy. METHODS: A PubMed search without time restriction was conducted to identify all relevant studies in accordance with the PICOT question. Additionally, a search was also performed in the Cochrane library database, Internet, and citation. The CONSORT 2010 checklist and STROBE statement checklist were used to evaluate the risk of bias of the included studies. RESULTS: A total of 24 eligible articles were included, which consisted of 11 interventional and 13 observational studies. Intravesical therapy with Bacillus Calmette-Guérin (BCG) or certain chemotherapeutic agents worsens symptom burdens and functional performance during the initial induction phase while continuous improved is observed throughout the maintenance treatment and beyond. Hyperthermia has shown a positive trend in enhancing QoL of patients receiving intravesical chemotherapy, which requires more investigations. However, QoL data were unavailable for other forms of immunotherapy, immune checkpoint inhibitors, electromotive drug administration, and photodynamic therapy. CONCLUSIONS: Limited studies suggested the long-term positive impact of intravesical BCG immunotherapy and chemotherapy. However, existing evidence was lacking to clarify the impact of many emerging intravesical therapies that have suggested to be effective and safe, which demands treatment-specific QoL studies.

Evaluating the IVIVC by Combining Tiny-tim Outputs and Compartmental PK Model to Predict Oral Exposure for Different Formulations of Ibuprofen.

Nowadays, the ever-increasing costs of research and development in the pharmaceutical industry have created a big demand for predicting the performances of drug candidates. Of those, the desire to establish an in vitro-in vivo correlation (IVIVC) to better predict the oral drug exposure for different drug products is a growing need. Once a robust IVIVC is established, the performance of different drug products can be predicted and selected for testing in clinical trials with greater confidence. This tool will significantly reduce the cost and speed of drug development and provide new therapy to the patient faster. In this study, we explore combining the outputs of Triskelion's Gastro-Intestinal Model (Tiny-TIM) and multi-compartment pharmacokinetic model for a 200 mg ibuprofen product. The Loo-Riegelman method was used to calculate the amount of ibuprofen absorbed and was combined with the Tiny-TIM data to establish the IVIVC. The IVIVC was used to predict the exposures of both fast release and liquid gel formulations in humans. In general, the predicted exposure using Tiny-TIM-based IVIVC has good agreement with the clinical findings.

Elucidating a Potential Mechanism of Permeability Enhancer Sodium N-[8-(2-hydroxybenzoyl) amino] Caprylate in Rats: Evidence of Lymphatic Absorption of Cyanocobalamin using the Mesenteric Lymph Duct Cannulated Rat.

Oral administration is the most popular and convenient route for drug delivery, yet the success of oral drug delivery is dependent on the ADME properties of the drug. Among those ADME properties, permeability is considered one of the key attributes for successful oral drug absorption. Hence, the utilization of permeability enhancers to improve drug oral absorption is an important area of research in drug delivery. A multitude of data suggests that sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC) is an effective permeability enhancer. Despite its success, the mechanism of how SNAC works to enhance the oral absorption of compounds is poorly understood. To better understand how SNAC worked, we investigated the hypothesis of SNAC promotes lymphatic absorption of target compounds. In this study, cyanocobalamin was used as the model compound and mesenteric lymph duct cannulated rats were used to investigate its absorption with or without SNAC. The present study demonstrated that SNAC enhanced the lymphatic absorption of cyanocobalamin when the two were co-dosed in rats. Furthermore, levels of SNAC in lymph fluid and the systemic circulation were higher when co-dosed with cyanocobalamin.

A protocol for a randomized clinical trial assessing the efficacy of hypertonic dextrose injection (prolotherapy) in chronic ankle instability.

BACKGROUND: Lateral ankle sprain (LAS) is a common injury. Conservative care is not uniformly effective. Chronic ankle instability (CAI) results in up to 70% of patients with LAS in the physically active population. LAS, together with subsequent osteochondral lesions and pain in many patients, leads to the development of post-traumatic osteoarthritis, resulting in a substantial direct and indirect personal and societal health burden. Dextrose prolotherapy (DPT) is an injection-based therapy for many chronic musculoskeletal conditions but has not been tested for CAI. This protocol describes a randomized controlled trial to test the efficacy of DPT versus normal saline (NS) injections for chronic ankle instability (CAI). METHODS AND ANALYSIS: A single-center, parallel-group, randomized controlled trial will be conducted at a university-based primary care clinic in Hong Kong. A total of 114 patients with CAI will be randomly allocated (1:1) to DPT and NS groups. The primary outcome will be the Cumberland Ankle Instability Tool scores at 1 year. The secondary outcomes will be the number of re-sprains in 1 year, the Star Excursion Balance Test, the 5-level of EuroQol 5-dimension questionnaire, and the Foot and Ankle Ability Measure. All outcomes will be evaluated at baseline and at 16, 26, and 52 weeks using a linear mixed model. DISCUSSION: We hypothesized the DPT is a safe, easily accessible, and effective treatment for patients with CAI. This RCT study will inform whether DPT could be a primary non-surgical treatment for CAI. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2000040213 . Registered on 25 November 2020.

Comparative study of FosPeg® photodynamic effect on nasopharyngeal carcinoma cells in 2D and 3D models.

Photodynamic Therapy (PDT) offers an alternative option for the treatment of nasopharyngeal carcinoma (NPC). The utilization of 3-dimensional (3D) culture model might provide better understanding of PDT effects on NPC cells. The aim of this in vitro study was to compare PDT effect on NPC cells using 2D and 3D models. Two 3D culture models were established using liquid overlay method with agarose base (MCL) and hanging drop method (MCS). PDT was carried out using the combination of FosPeg® and 652 nm laser in 3D and conventional 2D models. The effects of 3D culture size and morphology on the uptake and distribution of sensitizer and gene expression were examined. Photocytotoxity, mode of cell death, and protein expression were compared for 2D and 3D models. Regular and irregular NPC spheroids were obtained from MCL and MCS methods, respectively. A significantly down-regulation of LMP1 mRNA were observed in MCL spheroid. The sensitizer uptake in 3D spheroids was half of 2D culture. More sensitizers were required to obtain IC50 in 3D spheroids. Apoptosis, necrosis and autophagosomes were detected in PDT treated 2D and 3D cells. Different protein expression patterns were observed in 2D and 3D models. FosPeg® PDT is effective in killing NPC cells. MCL-derived 3D spheroid model is more suitable for the evaluation of PDT killing mechanisms.

Prolonged control of patterned biofilm formation by bio-inert surface chemistry.

A bio-inert surface chemistry was developed that can confine biofilm formation in designed patterns for at least 26 days.

Intra-articular and extra-articular platelet-rich plasma injections for knee osteoarthritis: A 26-week, single-arm, pilot feasibility study.

AIM: Platelet Rich Plasma (PRP) is an emerging therapy for knee osteoarthritis (KOA). Studies have evaluated the effectiveness of intra-articular PRP, which ignores extra-articular tissue dysfunction and may provide incomplete treatment of KOA. The study aimed to pilot test a leukocyte-rich (mononuclear cells) PRP injection protocol for primary KOA, which consisted of single intra-articular injection and extra-articular injections on the medial coronary and medial collateral ligaments. METHODS: A prospective 26-week single-arm uncontrolled feasibility pilot study. Patients (N = 12) with primary KOA as defined by the American Rheumatology Association, with moderate to severe medial knee pain which failed conservative management, were recruited in a university primary care clinic and received a single session of PRP injection in week 1. The primary outcome was the feasibility of the protocol at 26 weeks as defined by rates of recruitment, compliance, retention, dropout, side effects or adverse events; and treatment satisfaction. Secondary outcomes included the Western Ontario McMaster University Osteoarthritis Index, the Intermittent and Constant Osteoarthritis Pain total and subscales, objective physical function tests and EuroQol-5D. RESULTS: Twelve of 40 potential patients were recruited in 3 months period (recruitment rate 30%, x2 = 3.33, P = 0.068). All participants adhered to the protocol and completed the follow up assessment with no dropouts (dropout rate 0%, X2= 2.67, P = 0.103). Satisfaction was high; no related adverse events were reported. Most secondary outcomes showed statistically significant improvement. CONCLUSIONS: Concomitant intra-articular and extra-articular PRP injections were feasible and produced preliminary favourable outcomes.

Comparison of the Demarcation Line on ASOCT After Simultaneous LASIK and Different Protocols of Accelerated Collagen Crosslinking: A Bilateral Eye Randomized Study.

PURPOSE: To compare the demarcation line depth after 2 different protocols of simultaneous laser in situ keratomileusis and collagen crosslinking (LASIK Xtra). METHODS: Twenty-three patients receiving bilateral LASIK Xtra were included in this comparative interventional study. The corneal stroma was soaked with 0.22% riboflavin for 90 seconds before flap repositioning. One eye was then randomized to receive either 18 mW/cm of ultraviolet A irradiation for 120 seconds or for 180 seconds, whereas the fellow eye received the other irradiation duration. The demarcation line on anterior-segment optical coherence tomography and grading of corneal haze on slit lamp were compared at postoperative month 1. RESULTS: The average age was 29.0 ± 8.2 years. There was no statistical difference in preoperative spherical equivalent refraction (P > 0.05). At postoperative 1 month, a well-defined demarcation line was visible in 74% and 70% in the 2- and 3-minute groups, respectively. The demarcation line depth was 282 ± 51 µm and 284 ± 43 µm, respectively (P = 1), and the ratio of the demarcation line depth to the postoperative central corneal thickness was 0.69 ± 0.13 and 0.72 ± 0.10 (P = 0.61). There was no difference in the percentage of eyes with grade 1 or 2 corneal haze (P = 0.76). CONCLUSIONS: The depth of the demarcation line was the same after receiving 18-mW/cm irradiation for either 2 or 3 minutes. The amount of early postoperative corneal haze was also similar. We postulate that there was lack of oxygen in the corneal tissue to fuel the photochemical reaction despite given additional time.

Clinical, radiological and ultrasonographic findings related to knee pain in osteoarthritis.

BACKGROUND: Pain is the predominant symptom of knee osteoarthritis (OA) and the main reason of disability. Ultrasound is now one of the new imaging modality in Musculoskeletal medicine and its role in assessing the pain severity in the knee osteoarthritis is evaluated in this study. OBJECTIVES: (1) To study the correlation between ultrasonographic (US) findings and pain score and (2) whether ultrasonographic findings show a better association of pain level than conventional X-rays in patients suffering from primary knee osteoarthritis. METHODS: In this multi-center study, 193 patients with primary knee OA were asked to score their average knee pain using the Western Ontario and McMaster Universities Arthritis (WOMAC) questionnaire;patients would then go for a radiological and an US evaluation of their painful knee. Findings from both imaging modalities will be studied with the associated pain score. RESULTS: Ultrasound showed that knee effusion has positive correlation with pain score upon walking (r = 0.217) and stair climbing (r = 0.194). Presence of suprapatellar synovitis had higher pain score on sitting (Spearman's Rank correlation  = 0.355). The medial(r = 0.170) and lateral meniscus protrusion (r = 0.201) were associated with pain score upon stair climbing. CONCLUSIONS: Our study found that both imaging modalities shown some significant association with the aspect of pain; neither one is clearly better but rather complementary to each other. A trend is found in both modalities: walking pain is related to pathologies of the either the lateral or medial tibiofemoral joint(TFJ)while stair climbing pain is related to both tibiofemoral joint pathologies and also to the patellofemoral joint (PFJ) pathology. This suggested that biomechanical derangement is an important aspect in OA knee pain.

FosPeg® PDT alters the EBV miRNAs and LMP1 protein expression in EBV positive nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC) is one of the top ten cancers highly prevalent in Hong Kong and South China. Epstein-Barr virus (EBV) infection contributes to the tumorigenesis of NPC through the expression of different viral proteins. Among these, Latent Membrane Protein 1(LMP1) is the major oncoprotein expressed by EBV. Foscan® (Biolitec AG), m-tetrahydroxyphenylchlorin (mTHPC)-based photosensitizing drug, has been used in the photodynamic therapy (PDT) for head and neck cancers. FosPeg® (Biolitec AG) is a new formulation of mTHPC contained in PEGylated liposomes with optimized distribution properties. In this in vitro study, the potential of FosPeg®-PDT on human EBV positive NPC cell (c666-1) and EBV negative cells (HK1 and CNE2) were investigated. Effects of FosPeg®-PDT on the expression of EBV BART miRNAs (EBV miRNA BART 1-5p, BART 16, and BART 17-5p), LMP1 mRNA and proteins on c666-1 cells were also elucidated. The killing efficacy of FosPeg®-PDT on NPC cells were determined by MTT assay after LED activation. Effects of FosPeg®-PDT on the expression of LMP1 mRNA and protein were examined by real time PCR and western blot analysis. FosPeg®-PDT demonstrated its antitumor effect on c666-1 cells in a drug and light dose dependent manner. LD30, LD50 and LD70 were achieved by applying LED activation (3J/cm(2)) at 4h post incubated cells with 0.05µg/ml, 0.07µg/ml and 0.3µg/ml FosPeg®, respectively. Up-regulation of both LMP1 mRNA and protein were observed after FosPeg®-PDT in a dose dependent manner. FosPeg®-PDT exerted antitumor effect on c666-1 cells through up-regulation of LMP1 protein. Understanding the mechanism of FosPeg®-PDT may help to develop better strategies for the treatment of NPC.

Effect of laser in situ keratomileusis on rebound tonometry and Goldmann applanation tonometry.

PURPOSE: To determine the influence of refractive surgery on intraocular pressure (IOP) measurements obtained using an iCare rebound tonometer and a Goldmann applanation tonometer. SETTING: School of Optometry, Hong Kong Polytechnic University, Hong Kong, China. METHODS: Intraocular pressure was measured using the rebound tonometer and applanation tonometer before and 1 month after uneventful LASIK for myopia. RESULTS: The IOP was measured in 96 eyes (96 patients). The preoperative IOP measured by rebound tonometry (mean 16.7 mm Hg +/- 3.0 [SD]) was statistically significantly higher than by Goldmann applanation tonometry (mean 15.4 +/- 2.5 mm Hg) (P<.01, Wilcoxon test). There was no statistically significantly difference in postoperative measurements between the 2 tonometers (mean 11.9 +/- 2.6 mm Hg and 12.0 +/- 2.4 mm Hg, respectively) (P>.05, Wilcoxon test). The mean difference between the 2 tonometers after LASIK was 0.1 +/- 2.1 mm Hg. The 95% limits of agreement ranged from -4.26 to 4.05 mm Hg. The IOP reduction with rebound tonometry was positively correlated with preoperative IOP. CONCLUSION: There was a greater decrease in IOP measurement after LASIK by rebound tonometry, showing this method was more affected by surgery.