Soft Lens Fitting PDF
Preview Soft Lens Fitting
ELSEVIER BUTIERWORTH HEINEMANN ©2007,ElsevierLimited.Allrightsreserved. Firstpublished2007 Nopart ofthispublicationmaybereproduced,storedinaretrievalsystem,or transmitted inanyformorbyanymeans,electronic,mechanical,photocopying,recordingor otherwise, without theprior permissionofthe Publishers.Permissionsmaybesought direcclyfrom Elsevier'sHealthSciencesRightsDepartment.1600JohnF.KennedyBoulevard,Suite1800, Philadelphia,PA19103-2899,USA:phone:(+1)21S2393804;fax:(+1)2152393805;or, e-mail:[email protected] requeston-lineviathe Elsevierhomepage(http:www.elsevier.com).byselecting'Supportandcontact'andthen 'CopyrightandPermission'. 15BN-13:978-0-7S06-8856-7 ISBN-10:0-7506-8856-4 BritishLibraryCataloguinginPublicationData Acataloguerecordforchisbook isavailablefromthe BritishLibrary. LibraryofCongressCataloginginPublicationData Acatalogrecordforchisbook isavailablefrom the LibraryofCongress. Note Knowledgeandbest practice inthisfieldare constantly changing.Asnewresearch and experiencebroaden our knowledge,changesinpractice,treatmentanddrugtherapy may become necessary or appropriate.Readers areadvisedto checkthe most current information provided(i)on proceduresfeatured or(ii)bythe manufacturerofeach productto beadministered,to verifythe recommendeddose or formula,the methodand duration ofadministration,andcontraindications.Itisthe responsibilityofthe practitioner, relyingontheir ownexperienceandknowledgeofthe patient,to makediagnoses,to determine dosagesandthe besttreatmentforeach individualpatient,andto takeall appropriatesafetyprecautions.Tothefullestextentofthe law,neitherthe publishernor theeditorsassumesanyliabilityforanyinjuryand/ordamage. ThePublisher Working together togrow librariesindevelopingcountries www.elsevier.com I....ww.bookaid.org Iwww.sabre.org _ yoursourcefor books, • journalsandmultimedia inthehealthsciences The www.elsevierhealth.com publisher's policyistouse papermanufactured fromsustainabletOfests I Printed inEurope Foreword Eye Essentials isa series of books intended to cover the core skillsrequired bythe eye care practitioner ingeneral and/or specialized practice.Itconsists of books covering awide range of topics rangingfrom: routine eye examination to assessment and management of low vision;assessmentand investigative techniques to digitalimaging;case reports and lawto contact lenses. Authors known for their interest and expertise intheir particular subject havecontributed books to this series.The reader willknow manyof them,as they havepublished widely within their respective fields.Eachauthor hasaddressed key topics intheir subject ina practical rather than theoretical approach,hence each book hasa particular relevance to everyday practice. Eachbook inthe series follows a similarformat and has been designed to allowthe reader to ascertain information easilyand quickly. Eachchapter has been produced ina user-friendlyformat, thus providingthe reader with a rapid-reference book that iseasy to use inthe consulting room or inthe practitioner's free time. Optometry and dispensing optics are continually developing professions,with the emphasis ineach being redefined as we learn more from research and as technology stamps its mark. The Eye Essentials series isparticularly relevant to the practitioner's requirements and as such willappeal to students, graduates sitting professional examinations and qualified Foreword practitioners alike.We hope you enjoy reading these books as viii much aswe haveenjoyed producing them. Sandip Doshi Bill Harvey Introduction Towards the end ofa sighttest,one ofthose utterances that the busypractitioner maydread is'Iwas wondering whether to go for contact lenses'. Practitioners who do not regularlyfitcontact lenses are often convinced that it has allbecome a bittoo complicated,and that contact lenses are best leftto the experts, whoever they are. Patients are discouraged from too activean interest byrather vaguelynegativeadvice.Of course,there are practitioners who activelyencourage their patients to use contact lenses,but inthe UKthey are a smallminority.Part of the reason maybe that Britons are uncomfortable with the active promotion ofanything,for fear of beingthought ofas'pushy' or (brace yourselves) 'showing off'.However,this seems a poor explanation for a UKcontact lens market of7%ofthe population, compared with a USmarketof 15%.There mayalso be a confidence factor at work here. ManyUKpractitioners have lost touch with modern contact lens practice, or at least aspects of it.The reasons vary.Some smallrural practices maysimplynot generate very much contact lensworkat all,or little beyond the odd dailydisposable.Some busy practices employ contact lens fitters, and the optometrists rarely see the contact lens patients exceptfor their spectacle refractions. Some optometrists have taken a career break,to raise children or pursue a different career path.After afew years infull-timemanagementofeither type,the contact lensworld can appear dauntinglyunfamiliar. When the authors beganfittinglenses,there were onlyafew Introduction soft lenses available,so lens material selection was easy. x Some ofthem wetted better than others,but none of them transmitted a decent amount of oxygen. Inthose simpler times, aftercare was also relativelyeasy.The slit-lamps thatwe had were notgood enough to see much (indeed, itwas not uncommon to practise without one), and when we did see something,we either did not know what caused it or did not havelenses that would deal with it.Aswith certain soap operas,you could take a year offthem and not havea lot to catch up with.These dayswe can see more and do more,and havea huge and bewildering choice ofoptions.What iseven worse,so do the patients. At one time, professional knowledge could be jealously hoarded.but now anyone with a computer and halfan hour can gainaccess to astonishing levelsof technical and clinicalinformation.This has spawned that most dreaded of patients - the 'Internet Bully'. Usuallymale,and not promoted to the levelsthat his intellect demands (at least inhisopinion). the Internet Bully surfs the web for ammunition with which to harass hisoptometrist.(And probably hisdoctor,dentist,and any other sort of'ist' he consults.) This book and its companion volume (Rigid Gas-Permeable Lenses) are aimed at those colleagues who wish to re-enter the contact lens mainstream,aswell as those entering itfor the first time as students and pre-registered optometrists.Italso aims to meet the requirements suggested inour new General Optical Council entry levelcompetencies.to which allqualified practitioners are meant to adhere ifthey are to maintain their place on the General Optical Council register. It isnot intended to be comprehensive or overly academic, but should enable the practitionerto givesound advice to their patients,and should provide a basison which to buildshould they wish to specialize further. And you should be able to handle the Internet Bully too. Dedication Such isthe pace ofchange.most contact lens books go outof date rapidly.So read itfast! Acknowledgments We are grateful to Chanel Kingand Heidi Harvey for their assistance with photographs. 1 Initial consultation Introduction 2 Shouldthis patient be wearing contact lenses? 2 Ocular health 3 General health 3 Visual factors 4 Psychological factors 5 Occupation and lifestyle 6 Financial considerations 6 Softor rigid? 7 Patient examination 8 General observation ofthe eyeand adnexa 8 Assessment ofthe palpebral conjunctiva 9 Assessmentofthe bulbar conjunctiva 11 The tearfilm 12 General examination ofthe cornea 15 Specific examination ofthe cornea 19 Bluelightexamination ofthe cornea 22 References 24 Initial consultation Introduction 2 The initial consultation with a prospective contact lens wearer is an important dialogue between the practitioner and patient that hasa number ofgoals: 1. to establish whether the patient issuitable for anytype of contact lens correction 2. to identifythe optimal contact lens correction for the individual patient 3. to establish reasonable expectations for the performance of the lenses and care system 4. to educate the patient so that their use of the lenses willbe safeand sensible S. to determine baseline information that can be used to monitor change that can influencefuture management decisions. The majority of contact lensfitting iselective (i.e.non-therapeutic),and the patientwillexerta degree of control over the lenses selected and their compliance with care systems.The principle of informed choice isimportant here. The patient must be givenenough information to make appropriate decisions (Le.those the practitioner approves of). The dayswhen the practitioner held a monopoly on information havelongdeparted. Most patients who presentfor contact lens fittingwillalso possess a computer and internet access. Therefore.information that isincorrector out of date willbe easilydetected,with consequent loss of credibilityfor the practitioner.It isimportantthat practitioners keep themselves wellinformed on current developments. Should this patient be wearing contact lenses? There are fewabsolute contraindications to contact lenswear these days,although there are manymore issues that maylimitit, or make it more complicated for the patient or practitioner. Should this patient be wearingcontact lenses] Ophthalmologic consultation isessential before fitting anyeye with active corneal pathology,and infectiveconditions should be 3 eliminated before fitting to minimizethe risk of microbial keratitis.The patient should be aware of anyfactors that will increase their risk,so that they can weighthis against the benefits. Ocular health 1.Ocular surface disorders maycause problems: (a) Recurrent erosions maybe associated with anomalies of the basement membrane ofthe epithelium. Insevere cases, a bandage lens maybe indicated. (b) Recurrent bacterial infections willincrease the riskof microbial keratitis significantlyand ingeneral contact lenses should be avoided insuch patients. 2. Dry eye isthe most commonly encountered complication. The effect on contact lens wear can be predicted bythe severity of symptoms and corneal staining encountered before fitting.People with milder symptoms can usuallybe given contact lenses,at least for part-time wear. 3. Meibomian gland dysfunction (MGD) can be a significant factor incontact lens intolerance and its prevalence is age-related. Fewer than 20%of patients under 20 years of age presentwith it,but two-thirds of over-65s are found to have MGD. General health Both systemic pathology and the medication used to treat it may be significantfactors when considering contact lenses. 1. Allergies maybe associated with a poortear filmand a tendency to develop inflammatory reactions to solutions or lens deposits. Dailydisposable lenses or non-preserved solutions maybe indicated. 2. Chronic infections such as sinusitis or catarrh maycause excessive mucus inthe tears.The eyes mayalso be more prone to infection.
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