Shift-Volatility Transmission in East Asian Equity Markets

This paper attempts to provide evidence of "shift-volatility" transmission in the East Asian equity markets. By shift-volatility, we mean the volatility shifts from a low level to a high level, corresponding respectively to tranquil and crisis periods. We examine the interdependence of equity volatilities between Hong-Kong, Indonesia, Japan, Malaysia, the Philippines, Singapore, Thailand and the United States. Our main issue is whether shift-volatility needs to be considered as a regional phenomenon, or from a more global perspective. We find that the timing/spans of high volatility regimes correspond adequately to years historically documented as those of crises (the Asian crisis and the years following the 2008 crisis). Moreover, we suggest different indicators that could be useful to guide the investors in their arbitrage behavior in the different regimes: the duration of each state, the sensitivity of the volatility in a market following a change in the volatility in another market. Finally, we are able to identify which market can be considered as leading markets in terms of volatility

The use of comparative effectiveness research to inform policy decisions on the inclusion of bevacizumab for the treatment of macular diseases in Thailand's pharmaceutical benefit package

Thunyarat Anothaisintawee,1,2 Pattara Leelahavarong,1 Tanapat Ratanapakorn,3 Yot Teerawattananon11Health Intervention and Technology Assessment Program, Ministry of Public Health, Nonthaburi, Thailand; 2Family Medicine Department and Section of Clinical Epidemiology and Biostatistics, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Department of Ophthalmology, Khon Kaen Univerity, Khon Kaen, ThailandAbstract: There is increasing impetus to use pharmaceutical interventions, ie, ranibizumab or bevacizumab, for the treatment of particular macular diseases. This paper describes the evidence and decision-making of the National List of Essential Medicines Committee that recently announced the inclusion of bevacizumab for the treatment of macular diseases in its pharmaceutical benefit package. The findings of a systematic review and meta-analysis in this paper indicate that the intravitreal administration of bevacizumab is superior to nonpharmaceutical treatments for age-related macular degeneration (AMD) and diabetic macular edema (DME), but inconclusive for retinal vein occlusion, given the limited evidence. The study also failed to distinguish among the differences in terms of visual acuity improvement, reduction of central macular thickness, and response to treatment between AMD and DME patients treated with bevacizumab and those treated with ranibizumab. Although bevacizumab was not licensed for AMD and DME, the committee decided to include bevacizumab in the National List of Essential Medicines. It is expected that many patients who are in need of treatment but who are unable to afford the expensive alternative drug, ranibizumab, will be able to receive this effective treatment instead and be prevented from suffering irreversible loss of vision. At the same time, this policy will help generate evidence about the real-life effectiveness and safety profiles of the drug for future policy development in Thailand and other settings.Keywords: bevacizumab, macular degeneration, diabetic macular edema, retinal vein occlusion, comparative effectiveness researc

Digital image processing software for diagnosing diabetic retinopathy from fundus photograph

Tanapat Ratanapakorn,1 Athiwath Daengphoonphol,2 Nawapak Eua-Anant,2 Yosanan Yospaiboon1 1KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; 2Department of Computer Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen, Thailand Objective: The aim of this study was to develop automated software for screening and diagnosing diabetic retinopathy (DR) from fundus photograph of patients with diabetes mellitus. Methods: The extraction of clinically significant features to detect pathologies of DR and the severity classification were performed by using MATLAB R2015a with MATLAB Image Processing Toolbox. In addition, the graphic user interface was developed using the MATLAB GUI Toolbox. The accuracy of software was measured by comparing the obtained results to those of the diagnosis by the ophthalmologist. Results: A set of 400 fundus images, containing 21 normal fundus images and 379 DR fundus images (162 non-proliferative DR and 217 proliferative DR), was interpreted by the ophthalmologist as a reference standard. The initial result showed that the sensitivity, specificity and accuracy of this software in detection of DR were 98%, 67% and 96.25%, respectively. However, the accuracy of this software in classifying non-proliferative and proliferative diabetic retinopathy was 66.58%. The average time for processing is 7 seconds for one fundus image.Conclusion: The automated DR screening software was developed by using MATLAB programming and yielded 96.25% accuracy for the detection of DR when compared to that of the diagnosis by the ophthalmologist. It may be a helpful tool for DR screening in the distant rural area where ophthalmologist is not available. Keywords: automated diabetic retinopathy software, diabetic retinopathy screening, fundus photography diagnosis, digital image processin

Randomised controlled study of conjunctival autograft versus amniotic membrane graft in pterygium excision

AIM: To determine whether amniotic membrane can be used as an alternative to conjunctival autograft after pterygium excision. METHODS: 287 eyes with either primary or recurrent pterygium were included in this study. All eyes were randomised to undergo conjunctival autograft or amniotic membrane transplantation after pterygium excision by a single surgeon. 106 eyes in primary pterygium and 14 eyes in the recurrent group were treated with conjunctival autograft, and 148 eyes in primary pterygium and 19 eyes in the recurrent group were treated with amniotic membrane transplantation. Patients were followed up at 6 weeks and 6 months after operation. The main outcome measurement was recurrence rate after surgery. RESULTS: In the conjunctival group, the recurrence rate was 12.3%, 21.4% and 13.1% for primary, recurrent and all pterygia, respectively. In the amniotic membrane group, the recurrence rate was 25.0%, 52.6% and 28.1% for primary, recurrent and all pterygia, respectively. The recurrence rate for all pterygia in the amniotic membrane group was significantly higher than that in the conjunctival group (p = 0.003). CONCLUSIONS: Amniotic membrane graft had a higher recurrence rate than conjunctival autograft. However, it is an alternative choice, especially for advanced cases with bilateral heads or patients who might need glaucoma surgery later

Incidence of and risk factors for chloroquine and hydroxychloroquine retinopathy in Thai rheumatologic patients

Nuanpan Tangtavorn, Yosanan Yospaiboon, Tanapat Ratanapakorn, Suthasinee Sinawat, Thuss Sanguansak, Chavakij Bhoomibunchoo, Wipada Laovirojjanakul KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand Objective: To study the incidences of and risk factors for chloroquine (CQ) and hydroxychloroquine (HCQ) retinopathy in Thai rheumatologic patients. Methods: A retrospective cohort study of 234 rheumatologic patients receiving either CQ or HCQ was conducted. Patients were divided based on whether or not they developed retinopathy as retinopathy-positive or negative groups. Medical records giving details regarding age, gender, body weight, underlying diseases, daily doses, and cumulative doses of CQ or HCQ were reviewed. CQ and HCQ retinopathy were diagnosed by indirect ophthalmoscopy, Humphrey visual field test, and optical coherence tomography. The main outcome measures were incidences and risk factors of CQ and HCQ retinopathy. Results: The CQ retinopathy was detected in 14 of 173 patients (8.09%) who received CQ for 139–2,033 days, cumulative doses from 14.3 to 325.1 g, and daily doses from 0.8 to 18.5 mg/kg/d. Their ages ranged from 27 to 65 years. When compared to the CQ retinopathy-negative group, only age, body weight, and cumulative dose showed statistically significant differences. The HCQ retinopathy-positive group was comprised of 2 of 61 patients (3.28%) who received HCQ for 660–828 days, cumulative doses from 80 to 130 g, and daily dose from 1.9 to 4.4 mg/kg/d. Their ages were 36 and 39 years. Compared to the HCQ retinopathy-negative group, there were no statistically significant differences in studied risk factors. Conclusion: Incidences of and risk factors for CQ and HCQ retinopathy were reported. Since most patients developed retinopathy earlier than 5 years, it is suggested that patients taking long-term CQ or HCQ should undergo ophthalmologic screening annually after the baseline examination. Keywords: chloroquine, hydroxychloroquine, retinopathy, incidence, risk factor

Macular sensitivity after half-dose verteporfin photodynamic therapy in central serous chorioretinopathy

Thuss Sanguansak, Prapapan Pitujaturont, Yosanan Yospaiboon, Suthasinee Sinawat, Tanapat Ratanapakorn, Chavakij Bhoomibunchoo Department of Ophthalmology, Faculty of Medicine, KKU Eye Center, Khon Kaen University, Khon Kaen, Thailand Objective: To study the macular sensitivity after half-dose verteporfin photodynamic therapy in patients with resolved central serous chorioretinopathy using the automated static perimeter.Methods: Prospective consecutive case study of 24 patients with resolved central serous chorioretinopathy was performed. The macular sensitivity was measured using a conventional automated static perimeter with the Swedish interactive threshold algorithm 10-2 and foveal threshold. Best corrected visual acuity, intraocular pressure, fundus examination, macular thickness, and volume were also examined. The mean macular sensitivities of the affected eyes and their normal fellow eyes were calculated and compared. P<0.05 was considered statistically significant.Results: The mean macular sensitivities of the affected eyes were lower than the normal fellow eyes with a statistically significant difference in all areas of the study (P<0.05). Best corrected visual acuity improved significantly from pretreatment (0.26±0.3 logMAR) to posttreatment (0.075±0.15 logMAR, P<0.05). Macular thicknesses in affected eyes were 230.66±67.34 µm and in the normal eyes were 238.33±92.26 µm (P=0.68). Macular volumes in affected eyes were 8.77±0.49 and in the normal eyes were 8.70±0.50 (P=0.60). These findings were not statistically significant.Conclusion: Eyes with resolved central serous chorioretinopathy after half-dose verteporfin photodynamic therapy had lower macular sensitivity than normal fellow eyes. These findings agreed well with the previous microperimetric studies. The conventional automated static perimeter can also be used when a microperimeter is not available. Keywords: macular sensitivity, half-dose photodynamic therapy, automated static perimeter, central serous chorioretinopath

Systemic abnormalities associated with retinal vein occlusion in young patients

Suthasinee Sinawat,1 Chavisa Bunyavee,2 Tanapat Ratanapakorn,1 Supat Sinawat,3 Wipada Laovirojjanakul,1 Yosanan Yospaiboon1 1KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; 2Department of Ophthalmology, Faculty of Medicine, Nawamindaradhiraj University, Bangkok, Thailand; 3Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand Objectives: To study the systemic abnormalities associated with retinal vein occlusion in patients aged ≤50 years with a particular emphasis on atherosclerotic diseases and thrombophilic disorders. Methods: Medical charts of patients, aged ≤50 years whose diagnoses were retinal vein occlusions during the period 1995–2015 were retrospectively reviewed. The primary outcome was the number of systemic abnormalities associated with these patients. Secondary outcomes included types of retinal vein occlusion and sites of occlusion. Results: Atherosclerotic diseases were the most common systemic abnormalities associated with retinal vein occlusion and accounted for 55.1% of the patients in the study. Hypertension in 27.55%, diabetes mellitus in 16.33%, and 5.1% with dyslipidemia were noted. The number of thrombophilic disorders seemed to be less than expected and were noted in only 5.1%. Other systemic abnormalities included viral hepatitis infection, systemic lupus erythematosus, and acquired immunodeficiency syndrome. Oral contraceptives were used by some patients. Conclusion: Atherosclerotic diseases remained the most commonly associated systemic diseases in the majority of these patients. Approach to these patients should include a screening for hypertension, diabetes mellitus, and lipid abnormalities. Thrombophilia should also be considered where no obvious atherosclerotic diseases are found or if the patient is <40 years old, a history of thrombosis or a family history of thrombosis is possible. Keywords: retinal vein occlusion, systemic diseases, young patients&nbsp

Factors affecting visual outcomes after treatment of infectious endophthalmitis in northeastern Thailand

Yosanan Yospaiboon, Anocha Intarapanich, Wipada Laovirojjanakul, Tanapat Ratanapakorn, Suthasinee Sinawat, Thuss Sanguansak, Chavakij Bhoomibunchoo KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand Objective: To determine factors affecting visual outcomes after treatment of infectious endophthalmitis during 2012–2016 at a large referral eye center in northeastern Thailand. Patients and methods: Medical charts of patients with a diagnosis of infectious endophthalmitis including demographic data, types of endophthalmitis, causative organisms, methods of treatment, anatomical, and functional outcomes were retrospectively reviewed. Factors associated with improved visual outcomes were analyzed.Results: Four hundred and eleven patients (417 eyes) were recruited for the study. The three most common types were post-traumatic (44.53%), post-operative (31.87%), and endogenous endophthalmitis (17.52%). Vitreous cultures revealed causative organisms in 41.25%. Most common Gram-positive organisms were coagulase-negative Staphylococcus 30% (36/120), Bacillus spp. 20% (24/120), and Streptococcus pneumoniae 18.33% (20/120). Most common Gram-negatives were Pseudomonas spp. 24.32% (9/37), Klebsiella spp. 24.32% (9/37), and Enterobacter spp. 16.21% (6/37). Methods of treatment were medical treatment (18.71%) and surgical treatment (81.29%), including pars plana vitrectomy with or without silicone oil tamponade (62.59%) and destructive surgery (18.71%). After treatment, visual improvement was noted in 44.6%, stable vision in 18.47%, and worse vision in 36.93%. Factors associated with improved visual outcomes were post-operative endophthalmitis (P<0.001), coagulase-negative Staphylococcus (P=0.003), and initial visual acuity before treatment of hand motion or better (P=0.017).Conclusion: Most infectious endophthalmitis patients were post-traumatic, post-operative, and endogenous. The most common method of treatment was pars plana vitrectomy. Treatment could improve visual outcomes and at least stabilize the vision in 63.07%. Factors associated with improved visual outcomes were types of endophthalmitis, causative organisms, and initial visual acuity before treatment. Keywords: visual outcome, infectious endophthalmitis, prognostic factor

Predictive factors in the treatment of streptococcal endophthalmitis

Yosanan Yospaiboon, Kidakarn Meethongkam, Suthasinee Sinawat, Wipada Laovirojjanakul, Tanapat Ratanapakorn, Thuss Sanguansak, Chavakij Bhoomibunchoo KKU Eye Center, Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand Objective: To evaluate visual outcomes and possible predictive factors in the treatment of infectious endophthalmitis caused by Streptococcus species during 2012–2016 at a large referral eye center in northeastern Thailand.Methods: A retrospective medical record chart review of patients with culture-positive endophthalmitis caused by Streptococcus species was conducted. Demographic data including age, gender, occupation, duration of symptoms, time to surgery, surgical procedures, initial visual acuity at presentation, and final visual acuity after treatment were collected and analyzed. Possible predictive factors associated with improved visual outcomes were also studied.Results: Forty-five eyes of 45 patients were recruited for the study. The 3 most common types of endophthalmitis were postoperative (35.56%), posttraumatic (20%), and endogenous (15.56%). At presentation, most patients (95.56%) had visual acuity of hand motion (55.56%), light perception (28.89%), or no light perception (11.11%). The 3 most common isolates were Streptococcus pneumoniae (44.44%), Group B β-hemolytic Streptococcus (26.68%), and Streptococcus viridans (20%). Most patients (62.22%) were treated with surgical interventions, either pars plana vitrectomy with intravitreal antibiotics or pars plana vitrectomy with intravitreal antibiotics and silicone oil tamponade. After treatment, improved visual outcome was noted in only 9 patients (20%), and no visual improvement was seen in 36 patients (80%). Evisceration and enucleation were performed in 15 patients (33.33%). The only possible predictive factor associated with improved visual outcomes was early vitrectomy, performed within 3 days.Conclusion: Streptococcal endophthalmitis is often associated with poor visual prognosis. Only 9 patients (20%) had improved vision after treatment. The only possible predictive factor associated with improved visual outcomes was vitrectomy within 3 days. Early diagnosis and early vitrectomy are therefore recommended. Keywords: streptococcus endophthalmitis, visual outcomes, predictive factor