Displaying publications 1 - 20 of 57 in total

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  1. Chen RP, Chen Z, Chew KH, Li PG, Yu Z, Ding J, et al.
    Sci Rep, 2015;5:10628.
    PMID: 26024434 DOI: 10.1038/srep10628
    A caustic vector vortex optical field is experimentally generated and demonstrated by a caustic-based approach. The desired caustic with arbitrary acceleration trajectories, as well as the structured states of polarization (SoP) and vortex orders located in different positions in the field cross-section, is generated by imposing the corresponding spatial phase function in a vector vortex optical field. Our study reveals that different spin and orbital angular momentum flux distributions (including opposite directions) in different positions in the cross-section of a caustic vector vortex optical field can be dynamically managed during propagation by intentionally choosing the initial polarization and vortex topological charges, as a result of the modulation of the caustic phase. We find that the SoP in the field cross-section rotates during propagation due to the existence of the vortex. The unique structured feature of the caustic vector vortex optical field opens the possibility of multi-manipulation of optical angular momentum fluxes and SoP, leading to more complex manipulation of the optical field scenarios. Thus this approach further expands the functionality of an optical system.
    Matched MeSH terms: Visual Fields
  2. 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: Visual Fields
  3. Rosli Y, Bedford SM, Maddess T
    Invest Ophthalmol Vis Sci, 2009 Apr;50(4):1956-63.
    PMID: 18469194 DOI: 10.1167/iovs.08-1810
    This study examined the number and nature of spatiotemporal channels in the region where the frequency-doubling (FD) illusion would be expected to occur at eight locations spanning the central 30 degrees of the visual field.
    Matched MeSH terms: Visual Fields/physiology*
  4. Mohammed Z, Dickinson CM
    Ophthalmic Physiol Opt, 2000 Nov;20(6):464-72.
    PMID: 11127126 DOI: 10.1111/j.1475-1313.2000.tb01124.x
    For the reading task, contrast reserve is defined as the ratio of the letter contrast of the printed letters, to the reader's contrast threshold. Acuity reserve is the ratio of the print size used for the reading task, to the reader's visual acuity. The effects of low contrast reserve on reading performance were investigated at various magnifications, ranging from 3x to 7.5x, with the field of view systematically controlled. Eye movements were recorded whilst normally sighted subjects read using the magnifiers. It was shown that with adequate contrast reserve, increasing the field of view improved the reading rate because of the resulting increase in forward saccade length. Conversely, reducing the contrast reserve slowed the reading rate by decreasing the length of forward saccades and increasing the mean fixation duration, suggesting that the perceptual span is reduced at low contrast reserve. This study also shows that when the contrast reserve is low, providing magnification higher than that required for letter recognition (that is, increasing the acuity reserve) will not improve the reading performance. Furthermore, even when the contrast reserve was high, reading rates were lower for the magnifications of 5x and higher, because increases in saccade length do not match those of the retinal image size at these magnifications.
    Matched MeSH terms: Visual Fields/physiology*
  5. 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: Visual Fields
  6. Hanani Abdul Manan, Jafri Malin Abdullah, Zamzuri Idris, Mohammed Faruque Reza, Muhammad Hafiz Hanaf
    MyJurnal
    The present study discussed functional reorganization and alteration in respond to the slow-growing tumour,
    hemangiopericytoma in the occipital cortex. Visual evoked field (VEF) and auditory evoked field (AEF) using
    magnetoencephalography (MEG) was used to evaluate the source localization and brain activity. Results of VEF source
    localization show a typical brain waves. Brain activity of the occipital lobe demonstrate low activation in the ipsilateral
    to the tumour. However, result shows the activation on the contralateral hemisphere was high and bigger in activation
    volume. AEF result shows an identical source localization and both side of the temporal lobe are activated. This result
    suggests that there is a positive plasticity in auditory cortex and slow-growing tumour can induce functional reorganization
    and alteration to the brain.
    Matched MeSH terms: Visual Fields
  7. Agarwal R
    Medical Health Reviews, 2009;2009(1):75-93.
    MyJurnal
    Glaucoma, recognized as optic neuropathy is the second largest cause of blindness worldwide. The disease is characterized by progressive loss of retinal ganglion cells and visual field defects. The pathophysiological factors involved in the onset and progression of glaucoma are not fully understood. However, it is now well accepted that elevated intraocular pressure is not the only causative factor. The pathophysiology of glaucoma involves multiple factors that interact in a highly complex manner to favor development of glaucomatous optic neuropathy. As the knowledge of molecular mechanisms involved is expanding, more and more therapeutic targets are being recognized for the development of safe and effective pharmacotherapy of glaucoma. Although at present the intraocular pressure lowering drugs are still the first line of treatment, the prospect of introducing neuroprotective therapies that can directly protect and perhaps stimulate regeneration of dying and dead retinal ganglion cells, shows considerable promise. This review presents recent developments in the pathophysiology and pharmacotherapy of glaucoma.
    Matched MeSH terms: Visual Fields
  8. Ahmad SS
    Saudi J Ophthalmol, 2017 Jan-Mar;31(1):38-41.
    PMID: 28337061 DOI: 10.1016/j.sjopt.2016.08.001
    Glaucoma is a multi-factorial neurodegenerative disorder. The common denominator in all types of glaucomas is retinal ganglion cell death through apoptosis. However, this cellular demise in glaucoma is detected late by structural or functional analyses. There can be a 10-year delay prior to the appearance of visual field defects and pre-perimetric glaucoma is an issue still being addressed. However, a new cutting-edge technology called detection of apoptosing retinal cells (DARC) is being developed. This technique is capable of non-invasive, real-time visualization of apoptotic changes at the cellular level. It can detect glaucomatous cell damage at a very early stage, at the moment apoptosis starts, and thus management can be initiated even prior to development of visual field changes. In future, this technique will also be able to provide conclusive evidence of the effectiveness of treatment protocol and the need for any modifications which may be required. This article aims to provide a concise review of DARC technology.
    Matched MeSH terms: Visual Fields
  9. Ghanimi Zamli AK, Chew-Ean T, Wan Hitam WH
    Cureus, 2019 Apr 11;11(4):e4436.
    PMID: 31245223 DOI: 10.7759/cureus.4436
    Altitudinal visual field defect is a rare presentation of retrochiasmal lesion especially when bilateral visual fields were affected. In fact, bilateral inferior altitudinal visual field defect (BIAVFD) usually occurred in patients who survived a gunshot injury to the occipital lobe or as a direct trauma to the brain. We report a rare case of BIAVFD secondary to occipital meningioma. A high index of suspicion enables timely investigation and diagnosis when dealing with atypical presentation of intracranial meningioma.
    Matched MeSH terms: Visual Fields
  10. Tharmathurai S, Muhammad-Ikmal MK, Razak AA, Che-Hamzah J, Azhany Y, Fazilawati Q, et al.
    J Glaucoma, 2021 May 01;30(5):e205-e212.
    PMID: 33710066 DOI: 10.1097/IJG.0000000000001830
    PRCIS: Depression increases with severity of visual field defect in older adults with primary open-angle glaucoma (POAG).

    PURPOSE: This study aimed to determine the prevalence of depression among patients with POAG and examine the relationship between depression and the severity of POAG in older adults.

    MATERIALS AND METHODS: Three hundred and sixty patients with POAG aged 60 years or above were recruited from 2 tertiary centers located in an urban and suburban area. The participants were stratified according to the severity of their glaucoma based on the scores from the modified Advanced Glaucoma Intervention Study (AGIS) to mild, moderate, severe, and end stage. Face-to-face interviews were performed using the Malay Version Geriatric Depression Scale 14 (mGDS-14) questionnaire. Depression is diagnosed when the score is ≥8. One-way analysis of variance was used to compare the subscores between the groups. Multifactorial analysis of variance was also applied with relevant confounding factors.

    RESULTS: Depression was detected in 16% of older adults with POAG; a higher percentage of depression was seen in those with end stage disease. There was a significant increase in the mean score of mGDS-14 according to the severity of POAG. There was evidence of an association between depression and severity of visual field defect (P<0.001). There was a significant difference in mGDS-14 score between the pairing of severity of POAG [mild-severe (P=0.003), mild-end stage (P<0.001), moderate-severe (P<0.001), and moderate-end stage (P<0.001)] after adjustment to living conditions, systemic disease, and visual acuity.

    CONCLUSION: Ophthalmologists should be aware that older adults with advanced visual field defects in POAG may have depression. The detection of depression is important to ensure adherence and persistence to the treatment of glaucoma.

    Matched MeSH terms: Visual Fields
  11. Rosli Y, Bedford SM, James AC, Maddess T
    Vision Res, 2012 Sep 15;69:42-8.
    PMID: 22898702 DOI: 10.1016/j.visres.2012.07.019
    We compared photopic and scotopic multifocal pupillographic stimuli in age-related macular degeneration (AMD). Both eyes of 18 normal and 14 AMD subjects were tested with four stimulus variants presented at photopic and 126 times lower luminances. The multifocal stimuli presented 24 test regions/eye to the central 60°. The stimulus variants had two different check sizes, and when presented either flickered (15 Hz) for 266 ms, or were steady for 133 ms. Mean differences from normal of 5 to 7 dB were observed in the central visual field for both photopic and scotopic stimuli (all p < 0.00002). The best areas under receiver operating characteristic plots for exudative AMD in the photopic and scotopic conditions were 92.9 ± 8.0 and 90.3 ± 5.7% respectively, and in less severely affected eyes 83.8 ± 9.7% and 76.9 ± 8.2%. Damage recorded at photopic levels was possibly more diffusely distributed across the visual field. Sensitivity and specificity was similar at photopic and scotopic levels.
    Matched MeSH terms: Visual Fields/physiology
  12. Goh ASC, Kim YD, Woo KI, Lee JI
    Ophthalmology, 2013 Mar;120(3):635-641.
    PMID: 23149128 DOI: 10.1016/j.ophtha.2012.08.015
    OBJECTIVE: The orbital apex is an important anatomic landmark that hosts numerous critical neurovascular structures. Tumor resection performed at this complex region poses a therapeutic challenge to orbital surgeons and often is associated with significant visual morbidity. This article reports the efficacy and safety of multisession gamma knife radiosurgery (GKRS) in benign, well-circumscribed tumors located at the orbital apex.

    DESIGN: Retrospective interventional case series.

    PARTICIPANTS: Five patients with visual disturbances resulting from a benign, well-circumscribed orbital apex tumor (3 cases of cavernous hemangioma and 2 cases of schwannoma).

    METHODS: Each patient treated with GKRS with a total radiation dose of 20 Gy in 4 sessions (5 Gy in each session with an isodose line of 50%) delivered to the tumor margin.

    MAIN OUTCOME MEASURES: Best-corrected visual acuity, visual field changes, orbital imaging, tumor growth control, and side effects of radiation.

    RESULTS: All patients demonstrated improvement in visual acuity, pupillary responses, color vision, and visual field. Tumor shrinkage was observed in all patients and remained stable until the last follow-up. No adverse events were noted during or after the radiosurgery. None of the patients experienced any radiation-related ocular morbidity.

    CONCLUSIONS: From this experience, multisession GKRS seems to be an effective management strategy to treat solitary, benign, well-circumscribed orbital apex tumors.

    Matched MeSH terms: Visual Fields/physiology
  13. Embong M, Satgunasingam N, Rejab SM, Singh H
    Med J Malaysia, 1981 Mar;36(1):29-36.
    PMID: 7321934
    Matched MeSH terms: Visual Fields/drug effects*
  14. Rosli Y, Carle CF, Ho Y, James AC, Kolic M, Rohan EMF, et al.
    Sci Rep, 2018 02 14;8(1):2991.
    PMID: 29445236 DOI: 10.1038/s41598-018-21196-1
    Multifocal pupillographic objective perimetry (mfPOP) has recently been shown to be able to measure cortical function. Here we assessed 44 regions of the central 60 degrees of the visual fields of each eye concurrently in 7 minutes/test. We examined how foveally- and peripherally-directed attention changed response sensitivity and delay across the 44 visual field locations/eye. Four experiments were completed comparing white, yellow and blue stimulus arrays. Experiments 1 to 4 tested 16, 23, 9 and 6 subjects, 49/54 being unique. Experiment 1, Experiments 2 and 3, and Experiment 4 used three variants of the mfPOP method that provided increasingly improved signal quality. Experiments 1 to 3 examined centrally directed attention, and Experiment 4 compared effects of attention directed to different peripheral targets. Attention reduced the sensitivity of the peripheral locations in Experiment 1, but only for the white stimuli not yellow. Experiment 2 confirmed that result. Experiment 3 showed that blue stimuli behaved like white. Peripheral attention showed increased sensitivity around the attentional targets. The results are discussed in terms of the cortical inputs to the pupillary system. The results agree with those from multifocal and other fMRI and VEP studies. mfPOP may be a useful adjunct to those methods.
    Matched MeSH terms: Visual Fields/physiology*
  15. Shatriah I, Adlina AR, Alshaarawi S, Wan-Hitam WH
    Pediatr Neurol, 2012 May;46(5):293-7.
    PMID: 22520350 DOI: 10.1016/j.pediatrneurol.2012.02.020
    Limited data are available on optic neuritis in Asian children. Clinical profiles tend to vary with different races. We aimed to determine the clinical manifestations, visual outcomes, and etiologies of optic neuritis in Malaysian children, and discuss the literature of optic neuritis in Asian children. A retrospective study involving 14 children with optic neuritis was performed at Hospital Universiti Sains Malaysia between July 2005 and January 2010 (follow-up, 18-60 months). Clinical features, laboratory results, possible etiologies, and visual acuity after 1 year were studied. Females were predominant (mean age at presentation, 11.1 years). All patients manifested bilateral involvement. Swollen optic discs were observed in 92.9% of eyes; 60.7% of patients demonstrated a visual acuity of 6/60 (or 20/200) or worse on presentation, whereas 14.3% remained at 6/60 (or 20/200) or worse, 1 year after their attack. Cecocentral scotoma comprised the most common visual field defect. Infection contributed to 50.0% of cases; 14.3% progressed to multiple sclerosis during follow-up, with no evidence of recurrent optic neuritis. The clinical profiles and etiologies of optic neuritis in Malay children differ slightly compared with other optic neuritis studies of Asian children. The frequency of progression to multiple sclerosis is relatively lower.
    Matched MeSH terms: Visual Fields/physiology
  16. Liza-Sharmini AT, Ng GF, Nor-Sharina Y, Khairil Anuar MI, Nik Azlan Z, Azhany Y
    Med J Malaysia, 2014 Dec;69(6):245-51.
    PMID: 25934953 MyJurnal
    OBJECTIVE: To compare the clinical presentation, severity and progression of primary angle closure between Chinese and Malays residing in Malaysia.

    METHODS: A comparative retrospective record review study was conducted involving one hundred (200 eyes) Malay and fifty eight (116 eyes) Chinese patients. They were selected from medical records of Hospital Universiti Sains Malaysia, Kelantan and Hospital Pulau Pinang, Penang, Malaysia. The selected patients were re-diagnosed based on the International Society of Geographical and Epidemiological classification. The clinical data on presentation including the presence of systemic diseases were documented. Progression of the disease was based on available reliable visual fields and optic disc changes of patients who have been on follow-up for at least five years.

    RESULTS: Malay patients presented at older age (61.4 years SD 8.4) compared to Chinese (60.6 years SD 8.3). There was significant higher baseline Intraocular Pressure (IOP) among Malays (34.7 SD 18.5mmHg) compared to Chinese (30.3 SD 16.7mmHg) (p=0.032). The Chinese patients presented with significantly better visual acuity (p<0.001) and less advanced cup to disc changes (p=0.001) compared to Malays. Malay patients progressed faster than the Chinese. Majority progressed within 1 year of diagnosis. Malays without laser peripheral iridotomy (LPI) have a 4 fold (95% CI 1.4, 10.9) risk of progression. Higher baseline IOP, more advanced visual field defect and absence of LPI was identified as significant predictors associated with progression.

    CONCLUSION: The Malays presented with more advanced angle closure glaucoma as compared to the Chinese in Malaysia. Aggressive disease progression was observed in Malays with the onset of optic neuropathy. Effective public awareness and aggressive management is important to prevent blindness in the Malaysian population.
    Matched MeSH terms: Visual Fields
  17. Rab’ie Rusdi, Mohd Zaki Awg Isa
    MyJurnal
    Introduction: Myopia is an emerging vision problem that causes public health and economic burden worldwide and associated with increased risk to many ocular conditions leading to blindness. This study aimed to evaluate patterns of visual field defects in Malay population with myopia. Methods: A retrospective study was conducted between January 2018 until June 2018 at MSU Eye Centre and data was obtained from patient records of Malay subjects with myopia and free from any ocular and systemic diseases. The spherical equivalent (SE) of the refractive errors and the global indices (mean deviation, MD and pattern of standard deviation, PSD) of OCULUS Twinfield® 2 with SPARK strategy were recorded for this study. Results: A total of 90 eyes with the mean age of 29.16 (SD: 10.27) years old and SE (M= -2.92 D, SD:2.94 D) were selected. The mean of MD was -1.71 dB (SD 3.95 dB) and PSD was 1.81 dB (SD:1.82 dB) respectively. Significant differences was found in MD (p=0.012) and PSD (p=0.01) between the three groups. The localised field defect was observed in the moderate to high myopic eyes in all quadrants (p=0.01) for PP2, and also more prevalent pattern found in all quadrants for PP1 except at superior quadrant (p=0.08). Conclu- sions: There is a localised visual field defect found in a higher degree of myopia particularly at temporal, nasal and inferior quadrants. Thus, the visual field test is recommended as a routine procedure in moderate to high myopic eyes and need to be interpreted with caution.
    Matched MeSH terms: Visual Fields
  18. Hoe VCW
    JUMMEC, 2006;9(1):35-38.
    MyJurnal
    A cross-sectional survey of commercial vehicle drivers who were renewing their own licences was conducted at the Selangor Road Transport Department office in Padang Jawa between 1 February 2002 and 28 February 2002, using questionnaire and medical examination. The objective was to determine the prevalence of myopia, colour vision deficiency and visual field defect among the commercial vehicle drivers. The respondents that reported visual defect at the time of interview was compared with those detected by the author through medical examination. Out of the 223 respondents, 21 (9.4%) reported to have myopia by the questionnaire survey. Through the visual examination there were 63 (28.3%) with myopia (visual acuity worse than 6/12),six (2.6%) had a visual field defect and 14 (6.3%) had red-green colour deficiency. The visual defect detected during the study among the commercial vehicle drivers, which were missed at the time of the routine medical examination were significant. The process of the statutory medical examination should be reviewed.
    Matched MeSH terms: Visual Fields
  19. Tan AK, Mallika P, Md Aziz S, Asokumaran T, Intan G
    Malays Fam Physician, 2009;4(1):26-29.
    PMID: 25606155 MyJurnal
    A forty-two year old lady presented with gradual, painless, progressive blurring of vision of her left eye for four months. There were no other associated ocular or systemic complaints. Examination showed decreased visual acuity in both eyes and a pale optic disc on the left side. Visual field examination revealed a temporal field defect of the right eye which aroused the suspicion of an intracranial mass lesion. MRI of her brain revealed a suprasellar meningioma. We would like to emphasize the importance of visual field examination of both eyes in patients presenting with unilateral loss of vision.
    Matched MeSH terms: Visual Fields
  20. Haliza A, Md Muziman Syah M, Norliza M
    Malays Fam Physician, 2010;5(2):95-8.
    PMID: 25606195 MyJurnal
    PURPOSE: The objective of this study was to determine the prevalence of poor visual acuity, colour blindness and visual field defect of new Malaysian drivers.

    METHODS: A total of 3717 new drivers (50.2% males and 49.8% females) age 19±6 years, voluntarily participated in this study. Standard optometric apparatus such as LogMAR Charts, Ishihara plates and HandHeld Bernell Perimeter were used and standard procedures were applied.

    RESULTS: The visual examination showed 6.7% (n=250) of subjects achieved less than 0.3 LogMAR with better eye whilst 2.2% (n=83) had failed the Ishihara Test (2.1% males and 0.1% females). Most of the affected drivers were deutranopia. Only 2094 subjects had their visual field using a mobile Handheld Bernell Perimeter. 1.72% (n=36) subjects have less than 120 degrees of peripheral field of vision.

    CONCLUSIONS: The visual status among new Malaysian drivers needs to be taken seriously to ensure safe driving. Other factors such as colour vision and visual field screening have to be considered seriously when evaluating the visual performance of a driver. Good visual performance is indispensible for safe driving.
    Matched MeSH terms: Visual Fields
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