Routine Eye Examination

Total Page:16

File Type:pdf, Size:1020Kb

Routine Eye Examination Continuing education CET Routine eye examination Part 6 – Objective refraction Andy Franklin and Bill Harvey look at objective refraction, the various ways of undertaking it and what may influence the outcome. Module C8872, two general point for optometrists and dispensing opticians bjective refraction Adjusting the trial frame includes retinoscopy and The optical centres of the trial frame the use of autorefractors, should be set to the distance PD. If which are appearing in there is marked facial asymmetry you optometric practice in may need to measure half-PDs and increasing numbers. In adjust the trial frame accordingly. Later, O general, objective methods are not when you move on to near vision tests required to give us a final prescription. the optical centres can be adjusted to They merely need to get us to a point equal the near PD, and dropped slightly from which subjective methods can by adjusting the nosepiece of the trial take us to the end point accurately and frame. However, this should only be quickly. With an alert and compliant done if the spectacles that you intend subject it is possible to get an accurate to prescribe are to be set for near vision result using subjective methods alone, only. On a pre-presbyopic patient the but it takes time. In general, excessively optical centres should stay set for prolonged refraction of normal patients distance throughout the refraction, as is usually indicative of poor technique the near ocular motor balance will be rather than ‘professionalism’. With affected by the centration of the lenses practice, and if a previous prescription (Table 1). is known, objective refraction should Figure 1 If and the position of the nasal limbus is ● Look at the trial frame and check take seconds rather than minutes. the frame is measured, ensuring that you have not that it is level, allowing for any facial There are patients who are unable not level, moved the rule meanwhile. asymmetries that may be present. If the to participate in a subjective refrac- the cylinder The pupillary distance for near may frame is not level, the cylinder axis that tion, because of limitations of under- axis you be measured by instructing the patient you find may be wrong, and vertical standing or communication. The very find may be to look at the bridge of your nose. The prismatic effects may cause artefacts on young, those with Alzheimer’s disease wrong zero is lined up using the left eye and the binocular tests (Figure 1). or a learning disability may require that PD read using the right eye as before. ● Check that the pantoscopic angle of a prescription is arrived at purely from Quite why you would wish to do this the frame is sensible (Figure 2). If the the objective findings. is another matter. The actual amount of frame is wrongly tilted, high powered We should have realistic expectations inset required will vary with both the prescriptions may throw up significant of retinoscopy. It has been found that PD and working distance of the patient, errors in both sphere and cylinder. there is only a 50 per cent probability so unless you know these and place your ● Make sure that the back vertex that two consecutive measurements of nose in precisely the right position the distance is sensible. If the power of the sphere power would be within 0.40D. measurement is of dubious value. The sphere you find is over +/-4.00DS you They found that cylinder axis was the actual inset required is shown in Table should measure the BVD and note it on most repeatable, followed by cylinder 1 below. the final Rx. power, then sphere power. And, unless you are fully ambidextrous, you are likely to be better with one eye than TABLE 1 the other. Of course, the skill of the Trial frame inset for near vision for a range of PDs examiner will influence both accuracy and repeatability. Binocular inset for near vision at; PD 33cm 40cm Measuring pupillary distance It is important that we set up the trial 74mm 5.5mm 4.5mm frame accurately, because failure to do 70mm 5.0mm 4.5mm so may introduce significant artefacts 66mm 5.0mm 4.0mm into the result obtained. Use a frame 62mm 4.5mm 4.0mm rule and instruct the patient to look 58mm 4.5mm 3.5mm first at your left eye. Line up the zero 56mm 4.0mm 3.5mm cursor with the temporal limbus. The patient now looks at your right eye, 20 | Optician | 11.04.08 opticianonline.net CET Continuing education (a) (b) Figure 2 If the frame is wrongly tilted (a), high powered prescriptions may throw up significant errors Adding lenses to the trial frame visible, though complete darkness can ● Place spheres in the back cells of the stimulate accommodation. It might also trial frame. Where you are using more be difficult to find the trial lenses. than one sphere in the trial frame the most powerful should be at the back Position to minimise the vertex distance effects. You must try to work within 5° of the However, if you are using an Oculus visual axis, both horizontally and verti- or similar trial frame, which incorpo- cally. Adjust the chair height for verti- rates a built in vertex distance scale, cal alignment, allowing for the fact that the most powerful sphere should be the test chart may be above the patient, placed in the first of the rear cells (the so the patient may be looking slightly back cell one nearest the front). This is upwards. Errors of the order of -0.50DC the cell to which the scale is referenced x 90 occur if 10 degrees off horizontally. (Figure 3). Unless you have reduced vision in one ● When you change spheres, try to eye, use your RE to test the patients RE, ensure that the patient is never grossly Figure 3 The sphere in the first of the rear cells and LE for the patients LE. If this is under-plussed when you change lenses. impossible, the Barrett method should It is best to add the next plus lens before there is some evidence that the rings be employed. For horizontal alignment, you remove the current one. It can be on the green block of the duochrome get the patient to look at the green of the tricky with modern trial frames but it might be the one that produces least duochrome, get your head in the way becomes easier with practice. accommodation. In the absence of any and ask the patient to tell you when ● It is essential to make sure that all contradictory evidence the rings on they can just see the green panel. Ask lenses are thoroughly clean throughout the green would be the recommended the patient to tell you if your head gets refraction. Experience suggests this is fixation target for retinoscopy. in the way. often not the case. Light conditions Working distance A note on phoropters A darkened room will cause pupil You should work at a distance that allows Increasingly, phoropter heads are dilation and make the reflex more you to change the lenses in the trial used instead of trial frames. Modern automated lens carriages allow fast lens insertion, greater accuracy in axis location, more rapid comparison and presentation of lenses, use of variable prism, and a variety of further options depending on the model, such as immediate comparison of new refrac- tive findings with previous results. They are not advisable for a few situa- tions, notably low vision assessment and over-refraction of multifocal contact lenses, where the reduced light levels may affect visual performance or pupil size respectively (Figure 4). RETINOSCOPY Target Ideally, we want a target that will promote accurate and steady fixation but Figure 4 no stimulus to accommodation. Various A modern targets are used and they probably make phoropter little difference to the end result, but head opticianonline.net 11.04.08 | Optician | 21 Continuing education CET frame without changing body position, TABLE 2 and for most people this means that the Working distance lenses for retinoscopy working distance will be less than the 2/3m which seems to be the expected Working distance (cms) Working lens allowance (D) norm. Only the tall can reach if they 50 2.00 work at 2/3m and for many 1/2m is more realistic. It doesn’t matter what the 57 1.75 distance is provided that you know how 66 1.50 much to allow for your working lens 80 1.25 and the distance is maintained through- 100 1.00 out the test. Measure your customary working distance so that you know how much spherical power to allow for it. Make sure that you can return to it by TABLE 3 measuring with your arm. Usually the Acuity associated with mean sphere values base of the fingers or the wrist is used as a reference point, as this allows you Vision Equivalent sphere (myopia/manifest to change lenses without moving your hyperopia) body position. Check your working 6/5 PLANO distance when you have moved from 6/6 0.25 - 0.50 DS it (eg to change a lens). If your working distance allowance is wrong, errors in 6/9 0.50 - 0.75 DS the power of the sphere (and usually the 6/12 0.75 - 1.00 DS cylinder too) will result. For example, 6/18 1.00 - 1.25 DS if you are 100mm out at 2/3m the 6/24 1.25 - 1.75 DS sphere will be approximately 0.25D in 6/36 1.75 - 2.25 DS error.
Recommended publications
  • Prevention of Traumatic Corneal Ulcer in South East Asia
    FROM OUR SOUTH ASIA EDITION Prevention of traumatic corneal ulcer in South East Asia S C AE Srinivasan/ (c)M Country Principal Investigator and Lead Principal Investigator with village health workers in Bhutan Dr. M. Srinivasan ciasis, and leprosy, are declining, and (VVHW) of the Government were utilized Director Emeritus, Aravind Eye Care, soon the majority of corneal blindness will to identify ocular injury and treat corneal Madurai, Tamil Nadu India. be due to microbial keratitis. Most abrasion corneal ulcers occur among agricultural Myanmar: Village Health Workers (VHW) workers in developing countries following of the health department Introduction corneal abrasion. India: paid village volunteers were utilized Corneal ulceration is a leading cause of Several non-randomized prevention visual impairment globally, with a dispro- studies conducted before 2000 Inclusion criteria 2 portionate burden in developing (Bhaktapur Eye Study) and during 2002 • Resident of study area countries. It was estimated that 6 million to 2004 in India, Myanmar, and Bhutan • Corneal abrasion after ocular injury, corneal ulcers occur annually in the ten by World Health Organization(WHO), have confirmed by clinical examination with countries of South East Asia Region suggested that antibiotic ointment fluorescein stain and a blue torch encompassing a total population of 1.6 applied promptly after a corneal abrasion • Reported within 48 hours of the injury billion.1 While antimicrobial treatment is could lower the incidence of ulcers, • Subject aged >5 years of age generally effective in treating infection, relative to neighbouring or historic “successful” treatment is often controls.3-4 Prevention of traumatic Exclusion criteria associated with a poor visual outcome.
    [Show full text]
  • Physical Eye Examination
    Physical Eye Examination Kaevalin Lekhanont, MD Department of Ophthalmology Ramathibodi Hospp,ital, Mahidol Universit y Outline • Visual acuity (VA) testing – Distant VA test – Pinhole test – Near VA test • Visual field testing • Record and interpretations Outline • Penlight examination •Swingggping penli ght test • Direct ophthalmoscopy – Red reflex examination • Schiotz tonometry • RdditttiRecord and interpretations Conjunctiva, Sclera Retina Cornea Iris Retinal blood vessels Fovea Pupil AtAnteri or c ham ber Vitreous Aqueous humor Lens Optic nerve Trabecular meshwork Ciliary body Choriod and RPE Function evaluation • Visual function – Visual acuity test – Visual field test – Refraction • Motility function Anatomical evaluation Visual acuity test • Distant VA test • Near VA test Distance VA test Snellen’s chart • 20 ฟุตหรือ 6 เมตร • วัดที่ละขาง ตาขวากอนตาซาย • ออานทละตาานทีละตา แถวบนลงลแถวบนลงลางาง • บันทึกแถวลางสุดที่อานได Pinhole test VA with pinhole (PH) Refractive error emmetitropia myypopia hyperopia VA record 20/200 ผูปวยสามารถอานต ัวเลขทมี่ ี ขนาดใหญขนาดใหญพอทคนปกตพอที่คนปกติ สามารถอานไดจากท ี่ระยะ 200 ฟตฟุต แตแตผผปูปวยอานไดจากวยอานไดจาก ที่ระยะ 20 ฟุต 20/20 Distance VA test • ถาอานแถวบนสุดไไไมได ใหเดินเขาใกล chthart ทีละกาวจนอานได (10/200, 5/200) • Counting finger 2ft - 1ft - 1/2ft • Hand motion • Light projection • Light perception • No light perception (NLP) ETDRS Chart Most accurate Illiterate E chart For children age ≥ 3.5 year Near VA test Near chart •14 นวิ้ หรอื 33 เซนตเมตริ • วัดที่ละขาง ตาขวากอนตาซาย • อานทีละตา แถวบนลงลาง
    [Show full text]
  • Examination of The
    Colors and Eye Examination Techniques in Horses Equine Ophthalmology Service University of Florida There are really only 3 ophthalmic diseases!! 1. Corneal ulcers 2. Uveitis 3. Everything else!! Heine C-002-14-400 Heine C-002.14.602 Obvious Things Just stand back and look at the symmetry – Lashes – Discomfort and squinting – Tearing – Colors – Pupil – Clarity of cornea and lens – The normal eye is “shiny” – Anatomy: anterior to posterior 95677 Champagne RMH Lashes pointing down can be early Lashes sign of eye pain (ponies can look through their lashes) Nuclear Sclerosis Ocular Discomfort Level 107656 Dusty UF Res Corneal “Colors” White cornea: abscess or necrosis Blue cornea: edema Red cornea: vessels – Superficial (tree-like) and deep vessels (brush). – Note intensity of the red Dark is thin Shiny is thin Vascular Patterns Redness – Very Red – Pale Symmetry – Asymmetry 189711 154841 194013 Asymmetrical vascularization Callie Edema Corneal Haze – Endothelial – Uveitis Subepithelial scar Corneal abrasion/ulcer Subepithelial inflitrate – Immune mediated Fly – Fungal Mount Oakely IMMK Shooter Epithelial edema Sunshine Chief Barber IMMK Jupiter: DSA Chronic Recurrent Deep Immune Mediated Keratitis Green fluid filled lacunae form in the stroma “Alexiej” May SEK: fungi Candleabra SEK Pupil Size Dilated – Glaucoma – Retinal Disease – Optic Nerve Disease Miotic – Uveitis Deep corneal scrapings at the edge of the ulcer to detect bacteria and fungal hyphae Superficial swabbing cannot be expected to yield microbes in a high percentage of cases. Scrape with handle end of scalpel blade. Fluorescein: Every eye exhibiting signs of pain should be stained!! – Detects a corneal epithelial defect or “ulcer”. – Cobalt blue filter aids detection of abrasions.
    [Show full text]
  • Effects of Nd:YAG Laser Capsulotomy in Posterior Capsular Opacification
    Original Research Article Effects of Nd:YAG laser capsulotomy in posterior capsular opacification Praveen Kumar G S1, Lavanya P2*, Raviprakash D3 1Assistant Professor, 2Associate Professor, 3Professor & HOD, Department of Ophthalmology, Shridevi institute of Medical Sciences and Research Hospital, Sira Road, NH-4 Bypass Road, Tumkur- 572106, INDIA. Email: [email protected] Abstract Background: Posterior capsular opacification (PCO) is the most common long-term complication of cataract surgery in both phacoemulsification and extracapsular cataract extraction (ECCE). The overall incidence of PCO and the incidence of neodymium-doped yttrium–aluminum–garnet (Nd:YAG) laser posterior capsulotomy has decreased from 50% in the 1980s and early 1990s to less than 10% today. Reported complications of Nd:YAG laser posterior capsulotomy include elevated intraocular pressure, iritis, corneal damage, intraocular lens (IOL) damage, cystoids macular edema, disruption of the anterior hyaloid surface, increased risk of retinal detachment, and IOL movement or dislocation. In some patients, a refraction change is noticed after Nd:YAG laser posterior capsulotomy, but proving this remains difficult. Materials and Methods: Nd; YAG LASER capsulotomy was performed in 200 eyes of 200 patients, some with pseudophakia and some with aphakia at Kurnool medical college, Kurnool. They were followed up between October 2008 and September 2010. Results: Elevation of IOP has been well documented after anterior segment laser procedures. The IOP rise after YAG laser posterior capsulotomy is of short duration starting about 1 hr after laser procedure and lasting for 24 hrs. In this study, in 1case IOP came down to normal level after 3 days and in another case after 7 days.
    [Show full text]
  • Ophthalmology Abbreviations Alphabetical
    COMMON OPHTHALMOLOGY ABBREVIATIONS Listed as one of America’s Illinois Eye and Ear Infi rmary Best Hospitals for Ophthalmology UIC Department of Ophthalmology & Visual Sciences by U.S.News & World Report Commonly Used Ophthalmology Abbreviations Alphabetical A POCKET GUIDE FOR RESIDENTS Compiled by: Bryan Kim, MD COMMON OPHTHALMOLOGY ABBREVIATIONS A/C or AC anterior chamber Anterior chamber Dilators (red top); A1% atropine 1% education The Department of Ophthalmology accepts six residents Drops/Meds to its program each year, making it one of nation’s largest programs. We are anterior cortical changes/ ACC Lens: Diagnoses/findings also one of the most competitive with well over 600 applicants annually, of cataract whom 84 are granted interviews. Our selection standards are among the Glaucoma: Diagnoses/ highest. Our incoming residents graduated from prestigious medical schools ACG angle closure glaucoma including Brown, Northwestern, MIT, Cornell, University of Michigan, and findings University of Southern California. GPA’s are typically 4.0 and board scores anterior chamber intraocular ACIOL Lens are rarely lower than the 95th percentile. Most applicants have research lens experience. In recent years our residents have gone on to prestigious fellowships at UC Davis, University of Chicago, Northwestern, University amount of plus reading of Iowa, Oregon Health Sciences University, Bascom Palmer, Duke, UCSF, Add power (for bifocal/progres- Refraction Emory, Wilmer Eye Institute, and UCLA. Our tradition of excellence in sives) ophthalmologic education is reflected in the leadership positions held by anterior ischemic optic Nerve/Neuro: Diagno- AION our alumni, who serve as chairs of ophthalmology departments, the dean neuropathy ses/findings of a leading medical school, and the director of the National Eye Institute.
    [Show full text]
  • Study of Visual Outcome After Neodymium YAG Laser Therapy in Posterior Capsular Opacity
    perim Ex en l & ta a l O ic p in l h t C h f a o l m l Journal of Clinical and Experimental a o n l r o g u y o J ISSN: 2155-9570 Ophthalmology Research article Study of Visual Outcome after Neodymium YAG Laser Therapy in Posterior Capsular Opacity Pawan N. Jarwal* Department of Ophthalmology, Jaipuriya Hospital, Jaipur, Rajasthan, India ABSTRACT Purpose: Posterior capsular opacification is the most common long term complication of modern IOL surgery. Neodymium YAG laser remains the cornerstone of its treatment .In this study, an attempt was made to study the visual outcome following Neodymium YAG laser capsulotomy Methods: This was a prospective study of 50 patients conducted in Hospital , attached to R.U.H.S.-CMS Medical College ,Jaipur. All patients aged 50 years and above, attending the regular OPD who presented with visually significant posterior capsular opacification were treated with Neodymium YAG laser capsulotomy. After capsulotomy, follow up was done 1 – 4 hour after Capsulotomy, day one, end of first week, end of first month and at the end of minimum 3 months. During follow-up the visual acuity Intra Ocular Pressure (IOP) and other relevant tests were conducted and appropriate intervention were made during the follow-up period. Results: In my study duration of onsetofsymptoms of Posteriorcapsularopacity (PCO) is more between 2-3 years period after surgery. Pearls type of is Posteriorcapsular opacity more when compared to fibrous type. Most of the patients treated for Posterior capsular opacity with Neodymium: YAG laser capsulotomy showed an improvement in visual acuity .There was no incidence of major complications in patients treated with procedure.
    [Show full text]
  • Visual Impairment Care Needs of the Public Through Clinical Care, Research, and Education, All of Which Enhance the Quality of Life
    OPTOMETRY: OPTOMETRIC CLINICAL THE PRIMARY EYE CARE PROFESSION PRACTICE GUIDELINE Doctors of optometry (ODs) are the primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the visual system, the eye, and associated structures as well as identify related systemic conditions affecting the eye. Optometrists provide more than two-thirds of the primary eye care services in the United States. They are more widely distributed geographically than other eye care providers and are readily accessible for the delivery of eye and vision care services. Approximately 37,000 full-time equivalent doctors of optometry practice in more than 7,0000 communities across the United States, serving as the sole primary eye care provider in more than 4,300 communities. Care of the Patient with The mission of the profession of optometry is to fulfill the vision and eye Visual Impairment care needs of the public through clinical care, research, and education, all of which enhance the quality of life. (Low Vision Rehabilitation) OPTOMETRIC CLINICAL PRACTICE GUIDELINE CARE OF THE PATIENT WITH VISUAL IMPAIRMENT (LOW VISION REHABILITATION) Reference Guide for Clinicians Prepared by the American Optometric Association Consensus Panel on Care of the Patient with Low Vision Kathleen Fraser Freeman, O.D., Principal Author Roy Gordon Cole, O.D. Eleanor E. Faye, M.D. Paul B. Freeman, O.D. Gregory L. Goodrich, Ph.D. Joan A. Stelmack, O.D. Reviewed by the AOA Clinical Guidelines Coordinating Committee: David A. Heath, O.D., Chair John F. Amos, O.D., M.S. Stephen C. Miller, O.D.
    [Show full text]
  • Sequence of Examination Step I Note the General Appearance As You Take the History and When Initiating the Physical Examination, Usually with the Patient Sitting
    Introduction As well as history taking, Physical Examination is an important part of patient management. The goal of the P/E is to obtain valid information concerning the health of the patient. The examiner must be able to identify , analyze and synthesize the accumulated information into a comprehensive assessment. The four principles of physical examination are the following: 1. Inspection can provide an enormous amount of information. You must train themselves to look at the body using a systematic approach. 2. Palpation is the use of the tactile sense to determine the characteristics of an organ system. 3. Percussion relates to the tactile sensation and sound produced when a sharp blow is struck to an area being examined. This provides valuable information about the structure of the underlying organ or tissue. 4. Auscultation involves listening to sounds produced by internal organs. This technique furnishes information about an organ’s pathophysiology. To achieve competence in these procedures, the student must, "teach the eye to see, the finger to feel and the ear to hear" . Note: These four principles have different value in different systems. For example, Inspection is more useful in general appearance, Palpation in abdominal examination, Percussion in organ size evaluation, and Auscultation in heart examination. In abdominal examination, Auscultation is first, since performing percussion or palpation, may alter the frequency of bowel sounds. Preparing for the physical examination - Reflect on your approach to the patient - Decide on the scope of the examination - Adjust the lighting and the environment - Make the patient comfortable - Choose the examination sequence - Wash your hands in the presence of the patient - Describe your plans for the patient - Draped the patient.
    [Show full text]
  • Comparability Ratios for ICDA-8 and ICD-9-CM
    Comparability of Diagnostic Data Coded by the 8th and 9th Revisions of the International Classification of Diseases This report describes how the changes in the classification system used to code diagnoses reported in the National Hospital Discharge and the National Ambulatory Medical Care Surveys for utilization occurring in 1979 and later affect the comparability with similar data collected for utilization from 1968 through 1978. Comparability ratios are developed by coding the data using both coding classification revisions and dividing the national estimate based on one revision by the estimate based on the other revision. The comparability ratios can be used to estimate what the values published using one revision of the classification system would have been had coding been conducted according to the other revision. Data Evaluation and Methods Research Series 2, No. 104 DHHS Publication No. (PHS) 87–1 378 U.S. Department of Health and Human Services Public Health Service National Center for Health Statistics Hyattsville, Md. July 1987 Copyright information All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated. Suggasted citation National Center for Health Statistics, B. C. Duggar and W. F. Lew!s: Comparability of diagnostic data coded by the 8th and 9th revisions of the International Classification of Diseases. Vita/ and Heakh Statistics. Series 2, No. 104. DHHS Pub. No. (PHS) 87-1378. Public Health Service, Washington. U.S. Government Printing Office, July 1987 Library of Congrass Cataloging-in-Publication Data Duggar, 8enjamln C. Comparability of diagnostic data coded by the 8th and 9th revisions of the International Classification of Diseases.
    [Show full text]
  • IOC Mednick: Challenging Surgical Cases
    Top 5 Pearls to Consider When Implanting Advanced Technology IOLs in Patients With Unusual Circumstances Zale D. Mednick, BA Guillermo Rocha, MD, FRCSC ’ Pearl #1: The Use of a Toric Multifocal Intraocular Lens (IOL) in the Management of Hyperopic Astigmatism Background The mainstay of treatment for those with hyperopic astigmatism who wish to bypass the need for glasses or contacts has traditionally been laser treatment. Both hyperopic laser in situ keratomileusis (LASIK) and photorefractive keratotomy (PRK) have been used to correct hyperopic astigmatism. Although LASIK can provide promising results for a portion of patients with hyperopic eyes, it becomes less effective when dealing with more exaggerated degrees of hyperopia. Refractive results are much more successful for low diopter (D) hyperopia, with a drop in efficacy starting at + 4.00 to + 5.00 D.1 Esquenazi and Mendoza2 reported that when LASIK is performed on eyes with >5.00 D of hyperopia, both the safety profile of the procedure and the refractive outcomes dramatically decline, coinciding with decreased corrected distance visual acuity (CDVA). Choi and Wilson3 echoed this notion, citing a 2-line drop in CDVA when LASIK was used to treat hyperopia of 5.00 to 8.75 D. This is in stark contrast to the results achieved by LASIK to improve myopia, where corrections are feasible for a far greater range of refractions. Part of the reason that hyperopia is less amenable to correction of higher diopter errors may owe to the fact that larger ablation zones are needed to achieve better refractive results.4 The optimal size of the ablation zone for hyperopic LASIK is >5.5 mm,1 and as such, more corneal alteration is required.
    [Show full text]
  • Design and Methods in the Eye and Vision Consortium of UK Biobank
    Open access Cohort profile BMJ Open: first published as 10.1136/bmjopen-2018-025077 on 21 February 2019. Downloaded from Cohort profile: design and methods in the eye and vision consortium of UK Biobank Sharon Yu Lin Chua,1 Dhanes Thomas,1 Naomi Allen,2 Andrew Lotery,3 Parul Desai,1 Praveen Patel,1 Zaynah Muthy,1 Cathie Sudlow,4 Tunde Peto,5 Peng Tee Khaw,1 Paul J Foster,1 UK Biobank Eye & Vision Consortium To cite: Chua SYL, Thomas D, ABSTRACT Strengths and limitations of this study Allen N, et al. Cohort profile: Purpose To describe the rationale, methods and research design and methods in the potential of eye and vision measures available in UK ► UK Biobank is the largest prospective cohort with eye and vision consortium Biobank. of UK Biobank. BMJ Open extensive measures on ophthalmic diseases and Participants UK Biobank is a large, multisite, prospective 2019;9:e025077. doi:10.1136/ conditions. cohort study. Extensive lifestyle and health questionnaires, bmjopen-2018-025077 ► Repeated physical measures every few years and a range of physical measures and collection of biological linkage to National Health Service records will pro- ► Prepublication history for specimens are collected. The scope of UK Biobank was vide valuable information on health outcomes. this paper is available online. extended midway through data collection to include ► A large number of incident cases of eye diseases in To view these files, please visit assessments of other measures of health, including eyes the journal online (http:// dx. doi. 5 years will allow the detection and quantification of and vision.
    [Show full text]
  • Peripheral Refraction Vs. Optical Coherence Tomography
    Journal of Clinical Medicine Article Comparison of Methods for Estimating Retinal Shape: Peripheral Refraction vs. Optical Coherence Tomography Katharina Breher 1,* , Alejandro Calabuig 1 , Laura Kühlewein 1,2 , Focke Ziemssen 2 , Arne Ohlendorf 3 and Siegfried Wahl 1,3 1 Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; [email protected] (A.C.); [email protected] (L.K.); [email protected] (S.W.) 2 Center for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; [email protected] 3 Carl Zeiss Vision International GmbH, 73430 Aalen, Germany; [email protected] * Correspondence: [email protected] Abstract: Retinal shape presents a clinical parameter of interest for myopia, and has commonly been inferred indirectly from peripheral refraction (PRX) profiles. Distortion-corrected optical coherence tomography (OCT) scans offer a new and direct possibility for retinal shape estimation. The current study compared retinal curvatures derived from OCT scans vs. PRX measurements in three refractive profiles (0◦ and 90◦ meridians, plus spherical equivalent) for 25 participants via Bland–Altman analysis. The radial differences between both procedures were correlated to axial length using Pearson correla- tion. In general, PRX- and OCT-based retinal radii showed low correlation (all intraclass correlation coefficients < 0.21). PRX found flatter retinal curvatures compared to OCT, with the highest absolute agreement found with the 90◦ meridian (mean difference +0.08 mm) and lowest in the 0◦ meridian (mean difference +0.89 mm). Moreover, a negative relation between axial length and the agreement of both methods was detected especially in the 90◦ meridian (R = −0.38, p = 0.06).
    [Show full text]