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Fulltext The use of ultrasound in ocular biometry

Kuan BB, Lim TK

Med J Malaysia, 1984 Dec;39(4):280-4.
PMID: 6544933

Ultrasound measurement of ocular dimension is the chosen method for assessing axial length when determining dioptric power for intraocular lens. From the current results of 30 cases studied, the mean axial length ranges from 22 to 23 mm. Despite the limitation of the accuracy of the ultrasonic measurements with the 7.5 mHz transducer, the power of intraocular lens can. be determined satisfactorily in accordance with the knowledge of keratometric reading. Hence, high refractive errors could be avoided post-operatively.

Matched MeSH terms: Eye/anatomy & histology*
Fulltext Effect of Axial Eye Length on Retinal Vessel Parameters in 6 to 12-Year-Old Malay Girls

Tai EL, Li LJ, Wan-Hazabbah WH, Wong TY, Shatriah I

PLoS One, 2017;12(1):e0170014.
PMID: 28107389 DOI: 10.1371/journal.pone.0170014

PURPOSE: Retinal vessel analysis is affected by both systemic and ocular factors. Malays are the major ethnicity in South East Asia. Data on the retinal microvasculature in Malays is limited, especially among children. We aim to evaluate the influence of ocular biometry on retinal vessel parameters in young Malay girls.
METHODS: This was a cross-sectional, hospital-based study involving 86 Malay girls aged 6 to 12 years old in Hospital Universiti Sains Malaysia from 2015-2016. Ocular examination, refraction, biometry, retinal photography, and anthropometric measurements were performed. The central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE) and overall fractal dimension (Df) were measured using validated computer-based methods (Singapore I vessel analyzer, SIVA version 3.0, Singapore). The associations of ocular biometry and CRAE, CRVE and Df were analyzed using multivariable analysis.
RESULTS: The mean CRAE, CRVE and Df in Malay girls were 171.40 (14.40) um, 248.02 (16.95) um and 1.42 (0.05) respectively. Each 1 mm increase in axial length was associated with a reduction of 4.25 um in the CRAE (p = 0.03) and a reduction of 0.02 in the Df (p = 0.02), after adjustment for age, blood pressure and body mass index. No association was observed between axial length and CRVE. Anterior chamber depth and corneal curvature had no association with CRAE, CRVE or Df.
CONCLUSION: Axial length affects retinal vessel measurements. Narrower retinal arterioles and reduced retinal fractal dimension were observed in Malay girls with longer axial lengths.

Matched MeSH terms: Eye/anatomy & histology*
A new black fly species of Simulium (Nevermannia) (Diptera: Simuliidae) from Vietnam

Takaoka H, Low VL, Tan TK, Sofian-Azirun M, Chen CD, Lau KW, et al.

Acta Trop, 2019 Feb;190:320-328.
PMID: 30496721 DOI: 10.1016/j.actatropica.2018.11.025

Simulium pumatense sp. nov. is described from Vietnam, and is placed in the Simulium feuerborni species-group of the subgenus Simulium (Nevermannia) Enderlein. Its morphological characteristics include the relatively smaller numbers of the following three numerical features: inner teeth of the female mandible (15-18), minute conical processes (16) on the female cibarium, and male upper-eye facets (in 15 vertical columns and 16 horizontal rows). Keys are constructed to distinguish this species from four species of the same group in Vietnam. Our molecular analysis of the DNA barcoding COI gene shows that this species is most closely related to cytoform A of the S. feuerborni complex from Thailand.

Matched MeSH terms: Eye/anatomy & histology*
A Concise Review on Mesenchymal Stem Cells for Tissue Engineering with a Perspective on Ocular Surface Regeneration

Salih M, Shaharuddin B, Abdelrazeg S

Curr Stem Cell Res Ther, 2020;15(3):211-218.
PMID: 31995019 DOI: 10.2174/1574888X15666200129145251

Organ and tissue transplantation are limited by the scarcity of donated organs or tissue sources. The success of transplantation is limited by the risk of disease transmission and immunological- related rejection. There is a need for new strategies and innovative solutions to make transplantation readily available, safer and with less complications to increase the success rates. Accelerating progress in stem cell biology and biomaterials development have pushed tissue and organ engineering to a higher level. Among stem cells repertoire, Mesenchymal Stem Cells (MSC) are gaining interest and recognized as a cell population of choice. There is accumulating evidence that MSC growth factors, its soluble and insoluble proteins are involved in several key signaling pathways to promote tissue development, cellular differentiation and regeneration. MSC as multipotent non-hematopoietic cells with paracrine factors is advantageous for regenerative therapies. In this review, we discussed and summarized the important features of MSC including its immunomodulatory properties, mechanism of homing in the direction of tissue injury, licensing of MSC and the role of MSC soluble factors in cell-free therapy. Special consideration is highlighted on the rapidly growing research interest on the roles of MSC in ocular surface regeneration.

Matched MeSH terms: Eye/anatomy & histology*
The effects of metamaterial on electromagnetic fields absorption characteristics of human eye tissues

Gasmelseed A, Yunus J

Prog Biophys Mol Biol, 2014 Jan;114(1):8-12.
PMID: 24239501 DOI: 10.1016/j.pbiomolbio.2013.10.004

The interaction of a dipole antenna with a human eye model in the presence of a metamaterial is investigated in this paper. The finite difference time domain (FDTD) method with convolutional perfectly matched layer (CPML) formulation have been used. A three-dimensional anatomical model of the human eye with resolution of 1.25 mm × 1.25 mm × 1.25 mm was used in this study. The dipole antenna was driven by modulated Gaussian pulse and the numerical study is performed with dipole operating at 900 MHz. The analysis has been done by varying the size and value of electric permittivity of the metamaterial. By normalizing the peak SAR (1 g and 10 g) to 1 W for all examined cases, we observed how the SAR values are not affected by the different permittivity values with the size of the metamaterial kept fixed.

Matched MeSH terms: Eye/anatomy & histology
Fulltext Optimal Geometrical Set for Automated Marker Placement to Virtualized Real-Time Facial Emotions

Maruthapillai V, Murugappan M

PLoS One, 2016;11(2):e0149003.
PMID: 26859884 DOI: 10.1371/journal.pone.0149003

In recent years, real-time face recognition has been a major topic of interest in developing intelligent human-machine interaction systems. Over the past several decades, researchers have proposed different algorithms for facial expression recognition, but there has been little focus on detection in real-time scenarios. The present work proposes a new algorithmic method of automated marker placement used to classify six facial expressions: happiness, sadness, anger, fear, disgust, and surprise. Emotional facial expressions were captured using a webcam, while the proposed algorithm placed a set of eight virtual markers on each subject's face. Facial feature extraction methods, including marker distance (distance between each marker to the center of the face) and change in marker distance (change in distance between the original and new marker positions), were used to extract three statistical features (mean, variance, and root mean square) from the real-time video sequence. The initial position of each marker was subjected to the optical flow algorithm for marker tracking with each emotional facial expression. Finally, the extracted statistical features were mapped into corresponding emotional facial expressions using two simple non-linear classifiers, K-nearest neighbor and probabilistic neural network. The results indicate that the proposed automated marker placement algorithm effectively placed eight virtual markers on each subject's face and gave a maximum mean emotion classification rate of 96.94% using the probabilistic neural network.

Matched MeSH terms: Eye/anatomy & histology
Fulltext Distribution of axial length, anterior chamber depth, and corneal curvature in an aged population in South China

Chen H, Lin H, Lin Z, Chen J, Chen W

BMC Ophthalmol, 2016 May 01;16(1):47.
PMID: 27138378 DOI: 10.1186/s12886-016-0221-5

BACKGROUND: Ocular biometry is important for preoperative assessment in cataract and anterior segment surgery. The purpose of this study was to investigate normative ocular biometric parameters and their associations in an older Chinese population.
METHODS: This was a cross-sectional observational study. From 2013 to 2014, we recruited inhabitants aged 50 years or older in Guangzhou, China. Among 1,117 participants in the study, data from 1,015 phakic right eyes were used for analyses. Ocular parameters including axial length (AL), anterior chamber depth (ACD), and corneal curvature (K) were measured using an IOL Master.
RESULTS: The mean AL, ACD, and K were 23.48 mm [95 % confidence interval (CI), 23.40-23.55], 3.03 mm (CI, 3.01-3.05), and 44.20 mm (CI, 44.11-44.29), respectively. A mean reduction in ACD with age was observed (P = 0.002) in male subjects but not in female subjects (P = 0.558). Male subjects had significantly longer ALs (23.68 mm versus 23.23 mm, P

Matched MeSH terms: Axial Length, Eye/anatomy & histology*
Fulltext Dimorphic male scutal patterns and upper-eye facets of Simulium mirum n. sp. (Diptera: Simuliidae) from Malaysia

Takaoka H, Low VL, Sofian-Azirun M, Otsuka Y, Ya'cob Z, Chen CD, et al.

Parasit Vectors, 2016;9:136.
PMID: 26961508 DOI: 10.1186/s13071-016-1393-9

A species of Simulium in the Simulium melanopus species-group of the subgenus Simulium (formerly misidentified as S. laterale Edwards from Sabah and Sarawak, Malaysia) is suspected to have dimorphic male scutal color patterns linked with different numbers of upper-eye facets. This study aimed to confirm whether or not these two forms of adult males represent a single species.

Matched MeSH terms: Eye/anatomy & histology