Ophthalmic and Physiological OpticsThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

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Provision of NHS-funded spectacles in South LondonEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Discussion: In South London nearly a third of the practices do not provide VVS and it has been suggested that this is because the voucher values are uneconomic. The limited availability of VVS may act as one of the barriers that result in so many older people in the UK having poor vision simply through lack of appropriate spectacles. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 26, 2009 Category: Opthalmology Authors: Zahra Jessa, Bruce J.W. Evans, David W. Thomson, Gill Rowlands Source Type: journals

Relationship between accommodative and vergence dysfunctions and academic achievement for primary school childrenEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The purpose of this study was to investigate the prevalence and types of non-strabismic accommodative and/or vergence dysfunctions in primary school children, and to determine the relationship of these dysfunctions to academic achievement. A total of 1031 parents and their children aged 9[ndash]13 years responded to the College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. Of these, 258 children whose visual symptom scores were [ge]20 were identified for further evaluation. Comprehensive eye and vision examinations were provided to the children who met the eligibility criteria (114 of 258)...
Source: Ophthalmic and Physiological Optics - August 25, 2009 Category: Opthalmology Authors: Hoy S. Shin, Sang C. Park, Chun M. Park Source Type: journals

Discriminate characteristics of photopsia in posterior vitreous detachment, retinal tears and retinal detachmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Most patients with PVD have a typical presentation of photopsia, with temporal, vertically orientated, momentary flashes. Patients with RTs or RRD may describe subtle differences in their photopsia which may raise the index of suspicion for the presence of a complication from PVD. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 25, 2009 Category: Opthalmology Authors: Jonathan F. B. Goodfellow, Bataung Mokete, Tom H. Williamson Source Type: journals

Efficacy of different dry eye treatments with artificial tears or ocular lubricants: a systematic reviewEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Based on RB grading schemes used by numerous different clinicians over many years, treatment of dry eye with artificial tears or ocular lubricants can be expected to improve the condition of the exposed ocular surface. Assuming no improvement without treatment, a 30 days treatment period can be projected to produce an overall improvement of around 25%, but with no unambiguous statistical differences between product types. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 14, 2009 Category: Opthalmology Authors: Michael J. Doughty, Sara Glavin Source Type: journals

Quantification of heterophoria and phoria adaptation using an automated objective system compared to clinical methodsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion: This objective limbus tracking system offers a better means by which to study the phoria and its adaptation throughout an eye movement experiment. The broader aim of this research is to establish a tool that will further the basic science of oculomotor control and binocular dysfunctions. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 13, 2009 Category: Opthalmology Authors: Sang J. Han, Yi Guo, Bérangère Granger-Donetti, Vincent R. Vicci, Tara L. Alvarez Source Type: journals

Investigation of the causes of non-tolerance to optometric prescriptions for spectaclesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Spectacle prescription non-tolerance forms a small, but important, form of adverse reaction in optometric clinics. Most non-tolerances can be resolved by small changes, within 0.50 D, to the prescription. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 3, 2009 Category: Opthalmology Authors: Catherine E. Freeman, Bruce J. W. Evans Source Type: journals

The effect of treatment zone diameter in hyperopic orthokeratologyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The association of changes of treatment zone size with reductions in BCVA suggests that increasing CSZ may lead to better visual outcomes in hyperopic OK. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 2, 2009 Category: Opthalmology Authors: Paul Gifford, Helen A. Swarbrick Source Type: journals

Hyper-response of OP3 to systemic hyperoxia in the dark-adapted retinaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: This study provides further evidence indicating that the neural generators of OP3 display a unique hyper-reactivity to increased systemic O2 levels in the young healthy adult. Further studies looking at OP3 are still needed to determine if this unique behavior could serve as an index of altered oxygen level and retinal function in health or disease. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 2, 2009 Category: Opthalmology Authors: Caroline Faucher, Guillaume Carcenac, Hélène Kergoat Source Type: journals

Changes of higher-order aberrations with the use of various mydriaticsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Advances in corneal refractive surgery have allowed ophthalmologists to correct ocular higher-order aberrations. To obtain more information on the ocular aberrations generated from the optical axis, mydriasis is required. The aim of this study is to evaluate the changes in higher-order aberrations with the use of various mydriatics. Higher-order aberrations were measured in 21 eyes of 21 subjects (age range 24[ndash]37 years; 13 males, 8 females). Repeated measurements were conducted before and after the installation of three different mydriatics: 10% phenylephrine, 1% tropicamide, or 1% cyclopentolate. At a pupil size of ...
Source: Ophthalmic and Physiological Optics - August 2, 2009 Category: Opthalmology Authors: Jae-hyung Kim, Taehyung Lim, Myoung Joon Kim, Hungwon Tchah Source Type: journals

Increasing negative spherical aberration with soft contact lenses improves high and low contrast visual acuity in young adultsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Manipulation of spherical aberration, taking account of the participants' baseline level of aberration, can cause statistically significant improvements in high and low contrast distance visual acuity although these improvements are too small in magnitude to be of clinical significance. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 2, 2009 Category: Opthalmology Authors: Sheila M. Rae, Peter M. Allen, Hema Radhakrishnan, Baskar Theagarayan, Holly C. Price, Ananth Sailaganathan, Richard I. Calver, Daniel J. O'Leary Source Type: journals

Intra-examiner repeatability and agreement in accommodative response measurementsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The best method of assessing AR was Nott retinoscopy. The BCC technique was also repeatable, and both are recommended as suitable methods for clinical use. Despite better agreement between MEM and Nott, agreement among the remaining methods was poor such that their interchangeable use in clinical practice is not recommended. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - August 2, 2009 Category: Opthalmology Authors: B Antona, I Sanchez, A Barrio, F Barra, E Gonzalez Source Type: journals

Modeling the effect of facial topographies upon the visual field of humans and primatesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The model provides information on anatomical constraints for monocular and binocular visual field extensions including projection of the ventral field on a virtual floor. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - July 7, 2009 Category: Opthalmology Authors: C. Glittenberg, C. Schubert, D. Meisel, B. Viola, S. Binder, P. K. Ahnelt Source Type: journals

Clinical outcomes of corneal wavefront customized ablation strategies with SCHWIND CAM in LASIK treatmentsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The study results indicate that the aspheric corneal wavefront customized CAM approach for planning ablation volumes yields visual, optical, and refractive results comparable to those of other wavefront-guided customized techniques for correction of myopia and myopic astigmatism. The CW customized approach shows its strength in cases where abnormal optical systems are expected. Apart from the risk of additional ablation of corneal tissue, systematic wavefront-customized corneal ablation can be considered as a safe and beneficial method. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - July 6, 2009 Category: Opthalmology Authors: Maria Clara Arbelaez, Camila Vidal, Samuel Arba-Mosquera Source Type: journals

Clinical assessment of the lower tear meniscus heightEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion: Careful instillation of fluorescein does not affect normal TMH values. Fluorescein is washed out from the lower tear meniscus 5 min after instillation. Higher values of the TMH can be found at nasal and temporal locations compared to the center of the lower eye lid. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 29, 2009 Category: Opthalmology Authors: Carlos García-Resúa, Jacinto Santodomingo-Rubido, Madalena Lira, Maria Jesus Giraldez, Eva Yebra-Pimentel Vilar Source Type: journals

How well does record abstraction quantify the content of optometric eye examinations in the UK?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Our findings regarding optometric consultation mirror the findings in other healthcare disciplines: clinical records are an imperfect representation of the content of a clinical consultation. Clinical records are subject to a recording bias leading to both under- and over-estimation of the care provided due to the presence of false negatives and false positives. This study has important implications for clinico-legal cases, where clinical records are a key item of evidence; and our findings indicate that accurate record-keeping should be a priority for optometric continuing education. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 8, 2009 Category: Opthalmology Authors: Rakhee Shah, David F. Edgar, Bruce J. W. Evans Tags: Original Articles Source Type: journals

Winners in the 2008 Naylor Prize CompetitionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: W. N. Charman Tags: Announcement Source Type: journals

Intra-observer and inter-observer variation of Hertel exophthalmometryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion: Good intra-observer agreement was demonstrated using Hertel exophthalmometry. The inter-observer agreement was clinically acceptable. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: Andrew K. C. Lam, Chun-fai Lam, Wai-kit Leung, Pui-kwan Hung Tags: Technical Note Source Type: journals

A pilot study on the corneal biomechanical changes in short-term orthokeratologyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Short-term ortho-k treatment was shown to alter some corneal biomechanical properties. CRF was shown to decrease with increasing duration of lens wear. Further study is warranted to investigate the long term effect on corneal biomechanics from ortho-k treatment. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: Davie Chen, Andrew K. C. Lam, Pauline Cho Tags: Technical Note Source Type: journals

IOL calculation using paraxial matrix opticsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Matrix methods have a long tradition in paraxial physiological optics. They are especially suited to describe and handle optical systems in a simple and intuitive manner. While these methods are more and more applied to calculate the refractive power(s) of toric intraocular lenses (IOL), they are hardly used in routine IOL power calculations for cataract and refractive surgery, where analytical formulae are commonly utilized. Since these algorithms are also based on paraxial optics, matrix optics can offer rewarding approaches to standard IOL calculation tasks, as will be shown here. Some basic concepts of matrix optics ar...
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: Wolfgang Haigis Tags: Technical Note Source Type: journals

Axial length measurements before and after removal of silicone oil: a new method to correct the axial length of silicone-filled eyes for optical biometryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A total of 67 eyes of 67 patients that have undergone vitrectomy and silicone oil tamponade for rhegmatogenous retinal detachment were included in this prospective clinical study. We measured the axial length (AL) and the anterior chamber depth (ACD) with A-mode ultrasonography and IOL Master before and after removal of silicone oil. Phase refractive indices of silicone oil at different wavelengths from 400 nm to 1000 nm were measured with an Abbe refractometer and a series of equations were derived to adjust the AL values obtained with the IOL Master in silicone-filled eyes. The instruments showed good agreement between t...
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: Kai Wang, Meng-Ke Yuan, Yan-Rong Jiang, Yong-Zhen Bao, Xiao-Xin Li Tags: Original Articles Source Type: journals

Autonomic correlates of ocular accommodation and cardiovascular functionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: For sustained accommodation effort, the data demonstrate covariation between the oculomotor and cardiovascular systems which implies that a near visual task can significantly influence cardiovascular behaviour. Accommodative effort alone, however, is not a sufficient stimulus to induce autonomic differences between refractive groups. The data suggest that both the oculomotor and cardiovascular systems are predominantly attributable to changes in the systemic parasympathetic nervous system. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: Leon N. Davies, James S. Wolffsohn, Bernard Gilmartin Tags: Original Articles Source Type: journals

Cycloplegic refraction in preschool children: comparisons between the hand-held autorefractor, table-mounted autorefractor and retinoscopyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The table-mounted autorefractor provided a reading more similar to that of streak retinoscopy than to that of the hand-held autorefractor. However, there were only small differences in mean SE ( (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - June 3, 2009 Category: Opthalmology Authors: S. Prabakaran, M. Dirani, A. Chia, G. Gazzard, Q. Fan, S.-W. Leo, Y. Ling, K.-G. Au Eong, T.-Y. Wong, S.-M. Saw Tags: Original Articles Source Type: journals

The distribution of anterior chamber depth in a Tehran population: the Tehran eye studyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: We found the normal range of ACD in the population of Tehran which is slightly different from that reported from other geographical regions. The study also demonstrated the correlation of ACD with other factors; it decreases with age, and is slightly higher in men. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - May 15, 2009 Category: Opthalmology Authors: Hassan Hashemi, Mehdi KhabazKhoob, Shiva Mehravaran, Kamran Yazdani, Kazem Mohammad, Akbar Fotouhi Source Type: journals

Bifocals and Down's syndrome: correction or treatment?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Bifocals are an effective correction for the reduced accommodation in children with DS and also act to improve accommodation with a success rate of 65%. Bifocal wear can therefore be temporary, i.e. a 'treatment' for the deficit, in at least one third of children. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - May 11, 2009 Category: Opthalmology Authors: Mohammad Al-Bagdady, Ruth E. Stewart, Patrick Watts, Paul J. Murphy, J. Margaret Woodhouse Source Type: journals

Custom-devised and generic digital enhancement of images for people with maculopathyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Generic filters, which are easier to apply than the custom-devised filters, are appropriate for rehabilitation purposes. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - March 11, 2009 Category: Opthalmology Authors: Susan J. Leat, Ming Mei Source Type: journals

Correctable and non-correctable visual impairment among young males: a 12-year prevalence study of the Military Service in PolandEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Purpose: To evaluate the prevalence of correctable and non-correctable visual impairment in a representative sample of young males commissioned for Military Service in Poland.Material and methods: Data concerning vision status was retrospectively reviewed in 969 subjects of European Caucasian origin, most of whom live and have lived in Poland. They were selected from the original database comprising 105017 subjects examined in the period 1993[ndash]2004. Based on the age of subjects they were divided into two groups; group I aged 18[ndash]24 and group II aged 25[ndash]34 years. Visual impairment was defined as distance vis...
Source: Ophthalmic and Physiological Optics - March 9, 2009 Category: Opthalmology Authors: Michal S. Nowak, Roman Gos, Piotr Jurowski, Janusz Smigielski Source Type: journals

The content of optometric eye examinations for a presbyopic patient presenting with symptoms of flashing lightsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion: SP encounters are an effective way of measuring clinical care within optometry and should be considered for further comparative measurements of quality of care. As in research using SPs in other healthcare disciplines, our study has highlighted substantial differences between different practitioners in the duration and depth of their clinical investigations. This highlights the fact that not all eye examinations are the same but inherently different and that there is no such thing as a 'standard sight test'. Future optometric continuing education could focus on history taking, examination techniques and referra...
Source: Ophthalmic and Physiological Optics - February 11, 2009 Category: Opthalmology Authors: Rakhee Shah, David F. Edgar, Deacon E. Harle, Lynne Weddell, David P. Austen, David Burghardt, Bruce J. W. Evans Tags: Original Articles Source Type: journals

Author's ReplyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Timo Eppig Tags: Author's Reply Source Type: journals

Letter to the Editor: Assessing the optical performance of multifocal (diffractive) intraocular lensesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Michael J. Simpson Tags: Letter to the Editor Source Type: journals

Safe Mobility for Young and Old International Traffic Medicine Association (ITMA) 21st World Congress, The Hague, The Netherlands, 26–29 April, 2009Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Tags: Announcement Source Type: journals

The 2009 Ruskell MedalEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Tags: Announcement Source Type: journals

Tear ferning in contact lens wearersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tear ferning (TF) has shown good sensitivity and specificity in the diagnosis of dry eye, but is a relatively uncommon test, especially in contact lens wearers. The aim of this study was to investigate the relationship between TF, ocular comfort and tear film stability amongst contact lens (CL) wearers and non-contact lens (NCL) wearers. Subjects (36 NCL, 24 CL; mean age 23.2 ± 4.8 years) underwent assessment of non-invasive tear break up time (NIBUT), fluorescein tear break up time (FBUT) and completed the Ocular Comfort Index (OCI) questionnaire. Non-stimulated tears were collected from the inferior tear meniscus with a...
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Katharine S. E. Evans, Rachel V. North, Christine Purslow Tags: Original Articles Source Type: journals

Height, weight, body mass index and ocular biometry in patients with sickle cell diseaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Physical size does not affect refractive error or optical components in adult patients with SCD. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Ebi Peter Osuobeni, Iheanyi Okpala, Tom H. Williamson, Peter Thomas Tags: Original Articles Source Type: journals

A comparison of the Goldmann applanation and non-contact (Keeler Pulsair EasyEye) tonometers and the effect of central corneal thickness in indigenous African eyesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The Keeler Pulsair EasyEye gives reliable measurements of IOP in African eyes but is significantly affected by CCT. Particularly in borderline cases where management decisions have to be taken, it may be necessary to have pachymetric corrections based on an NCT algorithm, which appears steeper than the GAT algorithm. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: O. E. Babalola, A. V. Kehinde, A. C. Iloegbunam, T. Akinbinu, C. Moghalu, I. Onuoha Tags: Original Articles Source Type: journals

Diagnostic accuracy and variability of autorefraction by the Tracey Visual Function Analyzer and the Shin-Nippon NVision-K 5001 in relation to subjective refractionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Autorefraction measurements captured by both the Tracey and Shin-Nippon devices agree well with subjective refraction. The Shin-Nippon shows lower intratest variability. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: G. Cleary, D. J. Spalton, P. M. Patel, P.-F. Lin, J. Marshall Tags: Original Articles Source Type: journals

Accommodation modulates the individual difference between objective and subjective measures of the final convergence step responseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We presented a vertical line, a cross/rectangle stimulus and a difference-of-gaussians (DOG) pattern. For 180 min arc step stimuli, the subjective measures revealed a larger final vergence response than the objective measure; for the vertical line this SVO was 20 min arc, while it was significantly smaller for the DOG (12 min arc). For 60 min arc step-responses, no overestimation was observed. Additionally, we measured accommodation, which changed more for the DOG-pattern compared with the line-stimulus; this relative increase correlated with the corresponding relative change of SVO (r = 0.77). Both findings (i.e. no overe...
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: S. Jainta, J. Hoormann, W. Jaschinski Tags: Original Articles Source Type: journals

The influence of oblique viewing on axial and peripheral refraction for emmetropes and myopesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Refraction may be affected by the forces of lids and extraocular muscles when eye direction and head direction are not aligned (oblique viewing) which might potentially influence past findings on peripheral refraction of the eye. We investigated the effect of oblique viewing on axial and peripheral refraction. In a first experiment, cycloplegic axial refractions were determined when subjects' heads were positioned to look straight-ahead through an open-view autorefractor and when the heads were rotated to the right or left by 30° with compensatory eye rotation (oblique viewing). Subjects were 16 young emmetropes (18[ndash...
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Ankit Mathur, David A. Atchison, Sanjeev Kasthurirangan, Nadine A. Dietz, Suzanna Luong, Shih Pei Chin, Wen Linda Lin, Sock Whay Hoo Tags: Original Articles Source Type: journals

The difference between belief and reality for Viktorin's method of inter-pupillary distance measurementEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The variation in the measurement of an inter-pupillary distance and monocular centration distance by 54 registered practitioners using a 'pd rule' was investigated. Their estimate of the repeatability of the measurement was also recorded, as was any correction for their own inter-pupillary distance. There was found to be considerable variation between practitioners in all measurements, and the practitioners' estimated repeatability of the measurement was rather better than the reality. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: G. Walsh, E. I. Pearce Tags: Original Articles Source Type: journals

Users' subjective evaluation of electronic vision enhancement systemsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aims of this study were (1) to elicit the users' responses to four electronic head-mounted devices (Jordy, Flipperport, Maxport and NuVision) and (2) to correlate users' opinion with performance. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used these electronic vision enhancement systems (EVESs) for a variety of visual tasks. A questionnaire designed in-house and a modified VF-14 were used to evaluate the responses. Following initial experience of the devices in the laboratory, every patient took home two of the four devices for 1 week each. Responses were re-evalu...
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Louise E. Culham, Anthony Chabra, Gary S. Rubin Tags: Original Articles Source Type: journals

A new desktop instrument for measuring macular pigment optical density based on a novel technique for setting flicker thresholdsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A rapid portable technique for estimating macular pigment optical density (MPOD) in large populations is described. The new instrument utilises a novel method for setting flicker thresholds which is undemanding for naïve and elderly observers and easily operated by a non-technical person. The method has good repeatability (r = 0.97) and the data are comparable with an optical method based on retinal reflectometry (r = 0.78). MPOD spatial profiles are presented for seven normal observers and these are well described (r = 0.99) by a decaying exponential function consistent with previous reports. MPOD values are presented fr...
Source: Ophthalmic and Physiological Optics - February 10, 2009 Category: Opthalmology Authors: Rob L. P. van der Veen, Tos T. J. M. Berendschot, Fred Hendrikse, David Carden, Maria Makridaki, Ian J. Murray Tags: Original Articles Source Type: journals

Optical dispensing: the science of vision or blind faith?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The evidence for the basic optometric function of optical dispensing is discussed in terms of the basic principles of scientific debate. The degree of rigour applied to product testing and evaluation of most other medically related areas is lacking in the dispensing of spectacles. There has been much debate on the place of religious faith in our society. Religious belief masquerading as science has come in for particular scrutiny. However, little attention has been paid to the equally contentious issue of non-religious belief, within scientific disciplines, masquerading as science. It could be argued that optical dispensin...
Source: Ophthalmic and Physiological Optics - December 24, 2008 Category: Opthalmology Authors: Glyn Walsh Tags: Guest Editorial Source Type: journals

Determining the zone of reflection for posterior corneal surface comparison phakometryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although comparison phakometry has been used by a number of studies to measure posterior corneal shape, these studies have not calculated the size of the posterior corneal zones of reflection they assessed. This paper develops paraxial equations for calculating posterior corneal zones of reflection, based on standard keratometry equations and equivalent mirror theory. For targets used in previous studies, posterior corneal reflection zone sizes were calculated using paraxial equations and using exact ray tracing, assuming spherical and aspheric corneal surfaces. Paraxial methods and exact ray tracing methods give similar e...
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: Andrew Carkeet Tags: Technical Note Source Type: journals

Does binocularly perceived depth correlate with reduced stereoacuity?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion: The substantial individual and between-subject variation in Wirt Fly perceived depth causes us to doubt its value as a proxy for stereoacuity except as a rough estimate. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: Alexandra Lindstrom, Helen Davis, John P. Frisby Tags: Original Articles Source Type: journals

Reconstructing ocular surfaces by Purkinje images: an exact ray approachEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A method originally developed for corneal topography (using discrete sources and Zernike polynomials) was extended to estimate the geometry of ocular surfaces internal to the eye. The approach was tested in simulation as a candidate method for phakometry. Purkinje images from the anterior surface of an intra-ocular lens (IOL) (aligned and decentered) were simulated using the Navarro eye. The 'full' Navarro eye and a simplified eye were assumed for recovery purposes. Root mean square (RMS) errors and (anterior) IOL radii of curvatures (best-fit spheres) were estimated. The robustness of the method to axial shifts in lens po...
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: Jason Turuwhenua Tags: Original Articles Source Type: journals

Accommodation, pupil diameter and myopiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Concurrent measurements of steady-state accommodation response/stimulus curves and of pupil diameter were made in groups (n = 20) of young, adult myopes [age (mean ± SD) 23.1 ± 4.5 years, mean-sphere error (MSE) [minus]3.06 ± 2.35 D, range [minus]0.60 to [minus]8.54 D] and emmetropes (mean age 25.3 ± 5.7 years, mean MSE [minus]0.07 ± 0.26 D, range [minus]0.50 to +0.50 D). The aim of this study was to explore the possibilities that pupil diameters with relaxed accommodation were larger, and that accommodative miosis was weaker, in the myopic group. Such behaviour would lead to relatively greater degradation of the reti...
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: W. Neil Charman, Hema Radhakrishnan Tags: Original Articles Source Type: journals

The effect of altering spherical aberration on the static accommodative responseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Adding negative SA to the eye generally improves the slope of the accommodation stimulus-response curve and decreases lag of accommodation, and positive added SA depresses the slope of the stimulus-response curve and increases lag. The effect seems to be specific to SA, as there was no relationship between lag and RMS error. Altering SA may be a viable way of changing accommodative functions in clinical situations. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: Baskar Theagarayan, Hema Radhakrishnan, Peter M. Allen, Richard I. Calver, Sheila M. Rae, Daniel J. O'Leary Tags: Original Articles Source Type: journals

Age-related paraxial schematic emmetropic eyesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Based on recent biometric data, four-surface paraxial schematic emmetropic eyes for different ages have been developed. There are three sets of schematic eyes: male, female and overall. With increase in age, the changes in the schematic eyes are decreased anterior chamber depth, increased lens thickness, decreased vitreous length, increased axial length, decreased anterior lens radius of curvature and increased lens equivalent refractive index. Gender differences are greater anterior corneal radii of curvature (0.07 mm), longer vitreous chambers (0.70 mm), longer axial length (0.70 mm) and lower lens equivalent refractive ...
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: David A. Atchison Tags: Original Articles Source Type: journals

Soft contact lens cleaning: rub or no-rub?1Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Not rubbing the soft lens when cleaning is ineffective in removing loosely-bound deposits. A longer rinse, as recommended by the manufacturers, does not remove significantly more deposits than a shorter rinse with the MPS. This work supports the view that contact lens wearers should be encouraged to rub their lenses when cleaning. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: Pauline Cho, Suk Yi Cheng, Wai Yip Chan, Wing Kin Yip Tags: Original Articles Source Type: journals

The effectiveness of progressive addition lenses on the progression of myopia in Chinese childrenEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: Compared with SV lenses, myopia progression was found to be retarded by PALs to some extent in Chinese children without moderately or highly myopic parents, especially for subjects with near esophoria or females. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: Zhikuan Yang, Weizhong Lan, Jian Ge, Wen Liu, Xiang Chen, Linxin Chen, Minbin Yu Tags: Original Articles Source Type: journals

Referrals to ophthalmology: optometric and general practice comparisonEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusions: The differences between the two primary care practitioner groups may reflect variations in training, skills and practice. Further investigation of the particular strengths of both groups, and how they can be optimised to promote effective shared care, is required. (Source: Ophthalmic and Physiological Optics)
Source: Ophthalmic and Physiological Optics - December 22, 2008 Category: Opthalmology Authors: T. J. Pierscionek, J. E. Moore, B. K. Pierscionek Tags: Original Articles Source Type: journals