Displaying publications 1 - 20 of 58 in total

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  1. Highet HC
    Matched MeSH terms: Myopia
  2. Chen AH, Aziz A
    Malays J Med Sci, 2003 Jan;10(1):90-4.
    PMID: 23365507
    The purpose of this study was to investigate the relationship between heterophoria and refractive error. Thirty-six subjects (11 myopes, 25 emmetropes) participated in this study. Heterophoria was measured with the Free-Space Phoria Card at five different viewing distances (25cm, 33cm, 50cm, 100cm and 300cm). Regardless of the types of heterophoria, the amount of heterophoria reduced towards orthophoric position with increasing viewing distance. Emmetropes and myopes did not show any significant difference in the degree of heterophoria at different viewing distances (F = 0.30, p>0.05) or in the type of heterophoria (χ(2) = 2, p>0.05).
    Matched MeSH terms: Myopia
  3. Chung K, Mohidin N, O'Leary DJ
    Vision Res, 2002 Oct;42(22):2555-9.
    PMID: 12445849
    The effect of myopic defocus on myopia progression was assessed in a two-year prospective study on 94 myopes aged 9-14 years, randomly allocated to an undercorrected group or a fully corrected control group. The 47 experimental subjects were blurred by approximately +0.75 D (blurring VA to 6/12), while the controls were fully corrected. Undercorrection produced more rapid myopia progression and axial elongation (ANOVA, F(1,374)=14.32, p<0.01). Contrary to animal studies, myopic defocus speeds up myopia development in already myopic humans. Myopia could be caused by a failure to detect the direction of defocus rather than by a mechanism exhibiting a zero-point error.
    Matched MeSH terms: Myopia/etiology; Myopia/physiopathology; Myopia/therapy*
  4. Ahmad A, Mohd-Ali B, Ishak B
    Clin Optom (Auckl), 2018;10:109-113.
    PMID: 30319302 DOI: 10.2147/OPTO.S172272
    Purpose: Soft contact lens wear is most frequently associated with morphologic changes in corneal endothelial cells, but the data are scarce in Asians. This study aimed to evaluate changes in corneal endothelial cell morphology after 6 months of wearing soft hydrogel contact lenses (SH) in young myopic adults living in Kuala Lumpur.

    Patients and methods: Forty-eight subjects were included in the study, 24 were fitted with SH contact lenses (A) and the rest were prescribed with glasses (B). Refraction was conducted subjectively and standard contact lens fitting protocol was followed. Corneal endothelial cell morphology (endothelial cell density, ECD; coefficient of variation, COV; cells' hexagonality, HEX; and central corneal thickness, CCT) was evaluated using specular microscope. Data were collected at baseline and after 6 months of lens wear.

    Results: Mean age of all subjects was 21.23±1.30 years. All results are shown at baseline and 6 months, respectively. Mean refraction for A was -2.16±0.97 diopter sphere (DS) and -2.05±1.03 DS (P=0.49); for B was -2.72±1.51 DS and -2.73±1.51 DS (P=0.58). Mean ECD (cell/mm2) for A: 3104.19±237.30 and 3107.23±237.51 (P=0.07); for B: 3011.56±227.95 and 2983.83±244.55 (P=0.33). COV (%) for A: 46.52±8.63 and 48.53±10.65 (P=0.06); for B: 46.93±9.31 and 46.14±10.65 (P=0.88). HEX (%) for A: 46.21±10.12 and 45.15±10.01 (P=0.08); for B: 46.21±10.12 and 45.15±10.01 (P=0.12). CCT (µm) for A: 520.33±0.04 and 525.70±0.05 (P=0.41); for B: 532.00±0.04 µm and 530.00±0.05 µm (P=0.40).

    Conclusion: This study found no significant change in corneal endothelial cell morphology after 6 months of wearing SH contact lenses. This is probably due to better oxygen permeability of the contact lens material, good compliance, and short wearing period.
    Matched MeSH terms: Myopia*
  5. Thite N, Desiato A, Shinde L, Wolffsohn JS, Naroo SA, Santodomingo-Rubido J, et al.
    Cont Lens Anterior Eye, 2021 12;44(6):101496.
    PMID: 34426063 DOI: 10.1016/j.clae.2021.101496
    AIM: To understand the views of contact lens (CL) practitioners across the globe regarding what they perceive as opportunities and threats in CL practice.

    METHODS: A self-administered anonymised questionnaire, constructed in English and translated in six more languages, was distributed through reputed international professional bodies and academic institutions worldwide. The questionnaire included items on demographic characteristics, type of practice, and questions designed to explore practitioners' perspective on the future of their CL practice over the next five years.

    RESULTS: A total of 2408 valid responses were analysed. Multifocal CLs for presbyopia, CLs for myopia control, use of daily disposable (DD) CLs for occasional wear, and biocompatible materials to improve comfort were identified as promising areas of opportunities by practitioners (all 8/10). Respondents from North America, and Europe valued DDCLs for occasional wear moderately more favourable (Median: 9/10 for all) as compared to colleagues in Asia (Median: 8/10, p myopia control with CLs. Lack of regulation in CL sales, especially online, seemed to be a constant threat. The insights from this study can be used to design targeted strategies to enhance CL practice across the globe and in specific geographical areas.

    Matched MeSH terms: Myopia*
  6. Yeow PT
    Med J Malaysia, 1994 Jun;49(2):138-41.
    PMID: 8090092
    A cross-sectional study on a normal clinical myopic population reveals that there is a difference in the pattern of myopic progression between Malays and Chinese in Malaysia. It shows that while myopia in Malays stays relatively constant throughout 10 to 50 years of age, myopia in Chinese progresses rapidly from 10 to 20 years of age, after which it starts to show hyperopic shift, reaching a level of myopia similar to that of Malays at around 35 years of age. In view of the above finding it is postulated that the difference in myopia between the two races may be due to excessive accommodation in Chinese, causing a temporary increase in crystalline lens power and hence an increase in myopia. Because the magnitude of myopia for both races for 10 +/- 1 years age group is relatively high, i.e. about -2.00 D, it is postulated that myopia in these ethnic groups may start much earlier than 10 years of age.
    Matched MeSH terms: Myopia/ethnology*; Myopia/epidemiology
  7. Omar WEW, Singh G, McBain AJ, Cruickshank F, Radhakrishnan H
    Invest Ophthalmol Vis Sci, 2024 May 01;65(5):2.
    PMID: 38691091 DOI: 10.1167/iovs.65.5.2
    PURPOSE: To identify compositional differences in the gut microbiome of nonmyopes (NM) and myopes using 16S ribosomal RNA sequencing and to investigate whether the microbiome may contribute to the onset or progression of the condition.

    METHODS: Faecal samples were collected from 52 adult participants, of whom 23 were NM, 8 were progressive myopes (PM), and 21 were stable myopes (SM). The composition of the gut microbiota in each group was analysed using 16S ribosomal RNA gene sequencing.

    RESULTS: There were no significant differences in alpha and beta diversity between the three groups (NM, PM, and SM). However, the distributions of Bifidobacterium, Bacteroides, Megamonas, Faecalibacterium, Coprococcus, Dorea, Roseburia, and Blautia were significantly higher in the myopes (SM and PM combined) when compared with emmetropes. The myopes exhibited significantly greater abundance of bacteria that are linked to the regulation of dopaminergic signalling, such as Clostridium, Ruminococcus, Bifidobacterium, and Bacteroides. Individuals with stable myopia were found to have a significantly higher proportion of Prevotella copri than those with progressive myopia. Bifidobacterium adolescentis, a gamma-aminobutyric acid (GABA)-producing bacterium, was significantly higher in all myopes than in NM and, in the comparison between SM and PM, it is significantly higher in SM. B. uniformis and B. fragilis, both GABA-producing Bacteroides, were present in relatively high abundance in all myopes and in SM compared with PM, respectively.

    CONCLUSIONS: The presence of bacteria related to dopamine effect and GABA-producing bacteria in the gut microbiome of myopes may suggest a role of these microorganisms in the onset and progression of myopia.

    Matched MeSH terms: Myopia/microbiology; Myopia/physiopathology
  8. Goh PP, Azura R
    Med J Malaysia, 2012 Oct;67(5):497-502.
    PMID: 23770867 MyJurnal
    This is the first population based study on ocular biometric measurements (OBMs) conducted in Malaysia. Its objective is to measure and compare among children of different ethnicity who have myopia and emmetropia. Subsets of children aged between 7 and 8 years old who participated in a larger population based refractive error study had their axial length, anterior chamber depth, lens thickness and vitreous depth measured using A scan and vertical and horizontal corneal curvature measured using an autokeratorefractometer. Eighty eight of the 870 children (10.1%) examined had myopia. Boys, Chinese and children with myopia had significantly longer axial length and vitreous depth compared to girls, Malay and Indian and children who were emmetropic respectively. Girls and children with myopia had steeper corneal curvature. The baseline OBMs in Malaysian children of different ethnicity are valuable for studies in myopia progression. Like other studies, children with myopia have longer axial length (P <0.001). and vitreous depth (P <0.001) compared to children who are emmetropia (without myopia).
    Matched MeSH terms: Myopia*
  9. Chen AH
    PMID: 12152800
    The purpose of this study was to determine if there was any difference between myopes and emmetropes in using blur as a stimulus for accommodation when the chromatic aberration, size and proximal cues were eliminated. Twenty adults (10 myopes and 10 emmetropes) were examined for their accuracy of accommodation response for five different accommodation demands (OD, 1D, 2D, 3D, 4D) under two different light sources: achromatized white light versus monochromatic light. There was no significant difference in using blur stimulus between myopes and emmetropes when the chromatic aberration, size and proximal cues were eliminated.
    Matched MeSH terms: Myopia/physiopathology*
  10. Price H, Allen PM, Radhakrishnan H, Calver R, Rae S, Theagarayan B, et al.
    Optom Vis Sci, 2013 Nov;90(11):1274-83.
    PMID: 24100478 DOI: 10.1097/OPX.0000000000000067
    To identify variables associated with myopia progression and to identify any interaction between accommodative function, myopia progression, age, and treatment effect in the Cambridge Anti-Myopia Study.
    Matched MeSH terms: Myopia/diagnosis*; Myopia/physiopathology; Myopia/therapy*
  11. Allinjawi K, Sharanjeet-Kaur SK, Akhir SM, Mutalib HA
    F1000Res, 2016;5:2742.
    PMID: 28163898 DOI: 10.12688/f1000research.9971.1
    Aim: The purpose of this study was to compare the changes in relative peripheral refractive error produced by two different designs of progressive soft contact lenses in myopic schoolchildren. Methods: Twenty-seven myopic schoolchildren age between 13 to 15 years were included in this study. The measurements of central and peripheral refraction were made using a Grand-Seiko WR-5100K open-field autorefractometer without correction (baseline), and two different designs of progressive contact lenses (PCLs) (Multistage from SEED & Proclear from Cooper Vision) with an addition power of +1.50 D. Refractive power was measured at center and at eccentricities between 35º temporal to 35º nasal visual field (in 5º steps). Results: Both PCLs showed a reduction in hyperopic defocus at periphery. However, this reduction was only significant for the Multistage PCL (p= 0.015), (Proclear PCL p= 0.830).  Conclusion: Multistage PCLs showed greater reduction in peripheral retinal hyperopic defocus among myopic schoolchildren in comparison to Proclear PCLs.
    Matched MeSH terms: Myopia
  12. Shah Farez Othman, Nizam Tamchek, Farah Diana Muhammad, Shah Farez Othman, Shah Farez Othman, Mohd Hafidz Ithnin
    MyJurnal
    Current trend shows that the eye modelling is based on the emmetropic eye taken its ocular optical components value from the population-based studies. However, no studies have been done to study the effect of aberration of myopic refractive error by modelling the eye using the parameters from ocular biometrics and ray tracing method. The objective of the present study was to determine the spot diagram (SPD) profile of myopic refractive error using eye modelling and ray tracing technique. Three eye models had been successfully modeled in Zemax software, namely, emmetropic Liou and Brennan, myopic Liou and Brennan, corrected myopic Liou and Brennan. The optical performance of the eye models were tested using the SPD profile. The ray distribution from the analysis of SPD of myopic Liou and Brennan eye was larger compared to the emmetropic model. In comparison with the emmetropic Liou and Brennan model, for the blue wavelength, the RMS spot radius for the corrected version was increased. However, the RMS values were decreased for green and red wavelengths. For the corrected myopic version of Liou and Brennan, in comparison with its emmetropic model, the Airy disc diameter increased with the increment of wavelengths. It was found that the Airy disc diameter accuracy were higher for the blue, green and red wavelengths. Although the accuracy values were in a positive sign, for Airy disc diameter, the smaller value indicates a diffraction-limited condition.
    Matched MeSH terms: Myopia
  13. Chen AH, Aziz A
    Clin Exp Optom, 2002 12 17;82(5):182-186.
    PMID: 12482277
    BACKGROUND: The purposes of this study are to determine the viewing distance with minimum heterophoria and its relationship with refractive error and the resting position of accommodation. METHODS: The heterophoria and the accommodation responses of 36 optometry students (25 emmetropes and 11 myopes) were tested. Heterophoria was measured with the Free-Space Heterophoria Card at five different viewing distances (25 cm, 33 cm, 50 cm, 100 cm and 300 cm). The dioptric viewing distance with minimum heterophoria for each individual was estimated from the graph, where heterophoria in prism dioptres was plotted against viewing distance in centimetres. The Canon R-1 autore-fractor was used to determine the accommodation response at six different viewing distances (25 cm, 33 cm, 50 cm, 100 cm, 300 cm and 600 cm). The resting position of accommodation for each individual was estimated from the graph where the accommodative stimulus in dioptres was plotted against the accommodative response in dioptres. RESULTS: The dioptric viewing distance with minimum heterophoria ranges from 0.003 D to 0.65 D in emmetropes and ranges from 0.03 D to 2.36 D in myopes. There is no difference in the dioptric viewing distance with minimum heterophoria between myopes and emmetropes. Our results show a possible but not significant correlation between the dioptric viewing distance with minimum heterophoria and the resting position of accommodation. CONCLUSIONS: The viewing distance with minimum heterophoria is not affected by refractive error (stable early-onset myopia) and is poorly correlated with the resting position of accommodation.
    Matched MeSH terms: Myopia
  14. Md. Muziman Syah, M.M., Mutalib, H. A., Sharanjeet Kaur, M. S., Khairidzan, M. K.
    MyJurnal
    Introduction: The purpose of this study was to derive a modified equation for contact lens method (CLM) in
    calculating post myopic laser refractive surgery corneal power. Methods: A total of 93 subjects who
    underwent myopic laser refractive surgery at IIUM Eye Specialist Clinic were recruited. The accuracy of
    postoperative corneal power using the standard CLM and newly-derived contact lens modified method
    (CLMmod) were compared to the standard comparison method ; the historical method (HM). The CLMmod
    equation was derived by adjusting postoperative corneal power of CLM according to amount of refractive
    change. Results: The mean postoperative corneal power using standard CLM was significantly higher than
    HM (mean difference: -0.24 D, p < 0.001). Fifty seven percent (n = 53 eyes) of the standard CLM results were
    within ±0.50 D of HM results. The difference between postoperative corneal power using standard CLM and
    HM increased significantly with the amount of refractive change (r = 0.835; p < 0.001). The mean
    postoperative corneal power of CLMmod showed that there was no statistical significant difference compared
    to the HM results (mean difference: 0.00 D, p= 0.964). Eighty eight percent (n = 82 eyes) of the CLMmod
    results were within ±0.50 D of HM results with improvement of 31% from the standard CLM results.
    Conclusion: The CLMmod equation provides more accurate calculation in determining post myopic laser
    refractive surgery corneal power. In near future, this modified equation can be used as an alternative
    equation to calculate postoperative corneal power when the preoperative data is unavailable.
    Matched MeSH terms: Myopia
  15. Noor Aniah, A., Bastion, M.L.C., Mushawiahti, M.
    MyJurnal
    Retinal detachment is one of the common complications of pathological myopia due to presence of retinal break.
    However, retinal break commonly occurs in the peripheral retina. This case report illustrates the rare incidence of
    retinal break adjacent to the optic disc, highlights the possible causes of poor visual outcome following surgical
    repair as well as the possible measures to treat the complications.
    Matched MeSH terms: Myopia, Degenerative
  16. Azemin MZ, Daud NM, Ab Hamid F, Zahari I, Sapuan AH
    ScientificWorldJournal, 2014;2014:783525.
    PMID: 25371914 DOI: 10.1155/2014/783525
    The aim of this study was to compare the retinal vasculature complexity between emmetropia, and myopia in younger subjects.
    Matched MeSH terms: Myopia/physiopathology*
  17. Gasmelseed A
    Electromagn Biol Med, 2011 Sep;30(3):136-45.
    PMID: 21861692 DOI: 10.3109/15368378.2011.596248
    This article describes the analysis of electromagnetic energy absorption properties of models of the human eye with common visual disorders. The investigation addresses two types of visual disorders, namely hyperopia (or farsightedness) and myopia (or nearsightedness). Calculations were carried out using plane multilayered method with common wireless communication frequencies of 900, 1800, and 2450 MHz. The effect of wireless radiation on the eye is studied by calculation of the specific absorption rate (SAR) in three different eye models. The results of the simulations confirmed the anticipated and more complex relationship between absorption and structural variations of the eye at these frequencies.
    Matched MeSH terms: Myopia/metabolism*
  18. Allinjawi K, Kaur S, Akhir SM, Mutalib HA
    Saudi J Ophthalmol, 2020 12 28;34(2):94-100.
    PMID: 33575529 DOI: 10.4103/1319-4534.305035
    PURPOSE: The purpose was to determine the minimum near-addition power needed using Proclear® multifocal D-Design contact lens (adds: +1.50 D, +2.50 D, +3.00 D, and +3.50 D) to invert the pattern of relative hyperopic defocus in the peripheral retina into relative myopic defocus among the eyes of myopic schoolchildren.

    METHODS: Twenty-seven right eyes (24 females and 3 males) of 27 myopic schoolchildren aged between 13 and 15 years were included in this study. The measurements of central refraction, peripheral refraction (between 35° temporal and 35° nasal visual field in 5° steps), and lag of accommodation were conducted using the Grand-Seiko WR-5100K open-field autorefractometer initially without correction (WC), followed by with correction using four different addition powers of Proclear® multifocal D-Design contact lens in random sequence. Axial length was measured using a handheld probe ultrasound A-scan (Tomey AL-2000).

    RESULTS: The relative peripheral refractive error showed high hyperopic defocus of +1.08 ± 1.24 D at 35° nasal and +1.06 ± 1.06 D at 35° temporal visual field WC. All Proclear multifocal contact lenses (MFCLs) decreased the peripheral hyperopic defocus with increasing addition powers (F [2.938, 47.001] = 13.317, P < 0.001). However, only +3.00 D addition and +3.50 D addition (P = 0.001) could invert the peripheral hyperopic defocus into peripheral myopic defocus. Apart from that, the +3.00 D addition lens showed the lowest lag of accommodation (+1.10 ± 0.83 D) among the other MFCL adds (P = 0.002).

    CONCLUSION: A +3.00 D addition Proclear MFCL is the optimal addition power that can invert the pattern of peripheral hyperopic defocus into myopic defocus.

    Matched MeSH terms: Myopia
  19. Radhakrishnan H, Hartwig A, Charman WN, Llorente L
    Clin Exp Optom, 2015 Nov;98(6):527-34.
    PMID: 26450168 DOI: 10.1111/cxo.12296
    BACKGROUND: Differences in accommodation when reading Chinese, as compared to Latin, characters have been suggested to have a role in the higher prevalence of myopia in some Asian countries. Yeo and colleagues (Optom Vis Sci 2013; 90: 156-163) found that, in Chinese-literate children, accommodation was marginally more accurate (by less than 0.05 D), when reading Chinese text. This was attributed to the additional cognitive demand associated with interpreting the more complex Chinese symbols. The present study compared responses to single Chinese and Latin characters, while controlling for cognitive demand.
    METHODS: The monocular accommodative response was measured in Chinese-illiterate adults (10 emmetropes, mean spherical equivalent: -0.07 ± 0.42 D, age: 29.9 ± 4.2 years; 11 myopes, mean spherical equivalent: -4.28 ± 2.84 D, age: 31.7 ± 4.6 years) with an open-field autorefractor. Four Chinese and three Latin characters (approximately 1.15 degrees subtense) were individually presented on a display screen one metre away from the subject, while their vergence was varied over the range zero to 5.00 D using spectacle trial lenses. The slope and the accommodative error index (AEI) were calculated from the accommodative stimulus/response curves (ASRC).
    RESULTS: No statistically significant differences were found between refractive groups or among characters within the same refractive group in ARSC slopes (Latin: 0.87 ± 0.14 for myopes versus 0.81 ± 0.12 for emmetropes; Chinese: 0.84 ± 0.12 for myopes versus 0.85 ± 0.12 for emmetropes). No significant differences were found between characters in accommodative error index either (Latin, 0.78 ± 0.42 D for myopes versus 1.15 ± 0.72 D for emmetropes; Chinese, 0.74 ± 0.37 D for myopes versus 1.17 ± 0.83 D for emmetropes). However, accommodative error indices and accommodative errors were significantly higher for emmetropes.
    CONCLUSION: Under controlled cognitive demand, Chinese and Latin characters elicited similar responses in both individual refractive groups. This study fails to support the hypothesis that development of myopia in some Asian populations is associated with larger lags of accommodation when reading or viewing Chinese characters.
    Study site: Manchester, United Kingdom
    Matched MeSH terms: Myopia/ethnology; Myopia/physiopathology*; Myopia/therapy
  20. Norhani Mohidin, Saadah Mohd Akhir, Bariah Mohd Ali, Zainora Mohammed, Sharanjeet, K., Chung, K.M.
    MyJurnal
    A vision screening study was carried out among Indian schoolchildren around Kuala Lumpur to determine whether the prevalence of myopia was higher in boys or girls. Altogether 749 students (49.7% boys and 50.3% girls) aged 7-18 years were screened and their refractive error examined using retinoscopy without cycloplegia. For the right eye 15.1% of the girls' eyes were found to be myopic as compared to 16.9% of the boys, of which chi-square showed no significant difference (p = 0.44). For the left eye 18.8% of the girls' eyes were myopic as compared to 16.4% of the boys. Chi square also showed no significant difference (p = 0.26). When high myopia (> -6.00D) was considered, there was no difference found between boys and girls. The number of students with high myopia greater than -6.00D was also very small (0.3%-0.5%). In conclusion, it was found that there was no significant difference in myopia between girls and boys among Indian schoolchildren.
    Matched MeSH terms: Myopia
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