Ординатура / Офтальмология / Английские материалы / Medical Contact Lens Practice_Millis_2005

action of preservatives, particularly benzalkonium chloride.

The enzyme tablets are dissolved in saline, hydrogen peroxide or MPS solution, depending on the nature of the enzyme and solution. Subtilisin enhances the activity of hydrogen peroxide, causing a more rapid kill time for yeast. There is similar increased activity when pronase is used with peroxide and some MPS, but papain is ineffective in peroxide. It is therefore important to ensure that the correct solvent is used. This is normally to be found on the manufacturers’ instructions.

Liquid enzyme is now available – Optifree Supraclens (Alcon). The solution contains purified pancreatin and one drop is added daily to each lens chamber together with Optisoak or Optifree Express. There is no need for a separate weekly enzyming, making the system easier to use.

Enzymes do not remove deposits, but prevent their build-up, nor do they disinfect lenses, which must undergo a full disinfection cycle before being worn.

No cleaner can completely remove deposits and the effects of care systems on deposited lenses is variable because partial cleaning can alter the lens surface, which may behave differently when reinserted in the eye.8

DISINFECTION

Once lenses are clean contamination can be further reduced by disinfection. This is a process that kills or removes vegetative organisms and viruses, whereas sterilization involves the destruction of bacterial spores as well as vegetative organisms. Contact lens solutions are not sterilizing solutions and normally reduce the number of organisms to levels that are believed to be safe.

Heat is now rarely used as a method of disinfection, but is sometimes useful in areas of the world where solutions are difficult to obtain. Heat is not suitable for hard or RGP lenses, and if it is considered for soft lenses it is important to ascertain that the lens can be heated without damage. If the lens and case are to be placed in boiling water the lens case must also withstand heat. Alternatively it may be possible to use a small electric heater.

Chemical disinfection is the most commonly used method of disinfection. The cleaned lenses

are placed in disinfecting solution for the recommended period, which varies depending on the system, from 10 minutes to 6 hours.

Modern solutions may be classified as:

●hydrogen peroxide systems

●non-hydrogen peroxide systems.

Hydrogen peroxide systems

Hydrogen peroxide systems use 3% hydrogen peroxide to disinfect the lenses and a neutralizer to convert the peroxide to oxygen and water. They are available as multistep or one-step systems.

Multistep peroxide

The manufacturers recommend the cleaned lenses are immersed for 10 minutes in peroxide and neutralized for a further 10 minutes. Neutralizers include sodium pyruvate (10:10, CibaVision), catalase (Oxysept, Alcon) and sodium thiosulphate. Disinfection for 10 minutes is effective against bacteria, but fungi require 1 hour, and Acanthamoeba 3 or more hours. To improve disinfection, lenses can be left overnight in peroxide and neutralized the following morning, but there is a risk that the patient will fail to neutralize the solution in the morning. Hydrogen peroxide is an effective disinfectant. These systems do not contain preservatives, which may cause irritation or allergies, but they do contain unidentified stabilizers that can cause reactions.

The lenses tend to shrink in the peroxide and regain their former dimensions in the neutralizer. Longer periods of neutralization than those suggested by the manufacturer are preferred for group IV, nonionic high-water content lenses, for them to regain their former parameters.

Care needs to be taken to ensure that neutralization occurs because 3% hydrogen peroxide is toxic to the epithelium. If a lens is inserted in the eye without neutralization there is intense pain, watering and redness with varying amounts of epithelial staining. The lens should be removed immediately and the eye irrigated with copious amounts of sterile normal saline or water, if sterile solutions are not available. The patient should be warned that the eye will be uncomfortable for

24 hours, but it is unlikely that lasting damage has occurred.

One-step peroxide

In recent years “one-step” systems have become available in which neutralization is performed by a platinum-coated disc (AOSept®, CibaVision), or with a tablet of catalase with a delayed reaction coating (Oxysept One-Step®, Alcon). The main disadvantage with these systems is the rapid neutralization, which, in the case of AOSept®, commences immediately the peroxide comes in to contact with the platinum disc. There is rapid neutralization in the first 2 minutes followed by slow neutralization to approximately 15 ppm after 6 hours. With the tablet, neutralization occurs over 20 minutes, but full neutralization takes 2 hours. Longer periods of disinfection can be obtained by removing the tablet or disc, and reinserting it later, but this may introduce contamination and the delay risks the patient forgetting to add the neutralizer. This is less likely with the tablet, because it colors the solution pink, but the coating of the tablet can cause irritation if it fails to dissolve completely.

It has been noted that the residual peroxide increases as the coating of the platinum disc erodes over time, and so greater disinfection is obtained towards the end of the life of the disc,9 but there is a greater risk of epithelial damage. The disc is replaced monthly.

Kiel10 has shown that up to 40% of protein on soft lenses can be removed with the peroxide–catalytic disc system, and it has been suggested that AOSept® may cause less corneal staining and inflammatory response than MPS.11

Non-hydrogen peroxide systems

Multipurpose solutions

Multipurpose solutions were designed to improve compliance because it is believed that a one-bottle system that will clean, disinfect and rinse will encourage use. The solutions contain a surfactant, an antimicrobial agent for disinfection, EDTA to remove calcium ions and enhance the antimicrobial effect, and buffering agents.

Antimicrobials Many solutions now us polyquats, either polyhexanide or polyquad, a disinfectants. Derived from chlorhexidine, they have large molecules. Polyquad has the large molecule, and so cannot penetrate the lens matrix Each molecule is more effective, particularly a lower concentrations, than previous disinfectants which should reduce toxic and sensitivity reac tions. Polyhexanide selectively attacks microbia cell walls by binding to the plasma membrane, bu does not damage ocular cells. Both agents bind t mucus, so lenses should be clean before placing in disinfecting solution.

The bactericidal activity of polyhexamethylen biguanide (PHMB) has been shown to decreas with time until no activity remains after three days Polyhexamethylene biguanide appears to accumu late in the lens, which decreases the amount avail able in the solution. No such reduced bactericida activity or accumulation of polyquad was noted.12

Key and Monnat13 found 3% hydrogen perox ide could eradicate Pseudomonas aeruginosa with out a daily cleaning step while a polyquad system contained numerous colony-forming units unde the same conditions. Optifree Express (polyquad poloxamine and myristamidopropylmethylamine has some activity against Acanthamoeba tropho zoites and cysts.14

High levels of PHMB appear to cause greate discomfort and staining15 and all solutions may cause hyperemia, corneal staining, or an allergi response in susceptible individuals.

All MPS systems have similar antimicrobia activity. Multipurpose solutions have a longe duration of effect than peroxide because once per oxide is neutralized to oxygen and water, n antimicrobial activity remains. Lenses stored in neutralized solution are therefore more likely to become contaminated. Multipurpose solutions ar more suitable for those wearing lenses intermit tently because solutions need to be changed every 2–3 days, rather than daily.

One-bottle systems are convenient, but for thos patients who build deposits rapidly, separat cleaners and disinfectants may be preferable.

All care solutions in combination with contac lens wear may interact to cause increased epithe lial desquamation that may be sufficient to caus epithelial thinning.16

RINSING SOLUTIONS

Lenses may be rinsed with sterile normal saline or MPS. Saline is available as aerosols and in squeezable bottles. Aerosols are expensive and the nozzle may block with dried saline before the canister is fully used. More recently saline has been marketed in bottles in which antimicrobial activity is only aimed at maintaining the solution. This should be made clear to patients because they are often under the misapprehension that saline has antimicrobial activity and use it for lens storage.

Lens Plus Purite (Allergan) contains a stabilized chlorite, chlorate and traces of chlorine dioxide. In the presence of microorganisms chlorine dioxide forms with free radicals active against bacteria, viruses, fungi and yeasts.

CibaSaline contains sodium perborate. This forms boric acid and hydrogen peroxide (0.006%), which breaks down rapidly on the eye, under the influence of catalase and other enzymes in the tears, to oxygen and water. The hydrogen peroxide maintains the disinfection of the solution in the bottle and does not cause a toxic reaction in the eye.

These salines can be used for rinsing, cleaning the lens case and may be used as the solvent for the appropriate enzyme tablets.

SOLUTION BOTTLES

Solutions can easily become contaminated if the tops are left off the bottles because microorganisms can enter through the unprotected opening.17 Care should be taken that the tip of the bottle does not come into contact with fingers or other sources of contamination during use. It is important for patients and consulting room staff to ensure that all bottles are recapped immediately after use.

Bottles should not continue to be used after their expiry date because the build up of contaminants may reach levels against which the preservative is no longer effective.

Patients should be discouraged from decanting sterile contact lens solutions into other containers. Small containers are marketed for travel purposes, but the bottles are not sterile and may not be made of suitable plastic.

Patients must be encouraged to replace lens cases regularly (Fig 15 6)

Figure 15.6 Dirty contact lens case.

DISINFECTION OF CONTACT LENSES AND TONOMETERS IN THE CONSULTING ROOM

All consulting rooms have the potential to transmit infection from infected patients, office staff, dropper bottles and solutions, as well as diagnostic equipment, such as tonometer prisms, gonioscopy lenses and fundus lenses and reusable contact lens trial sets. Diseases such as AIDS (HIV virus), hepatitis B and C, adenovirus, herpes simplex, Acanthamoeba keratitis, as well as fungal and bacterial infections, can all potentially be transmitted by this route. Recently there has been the added problem of prion disease – new variant Creutzfeldt–Jacob disease (vCJD), for which there is no known method of sterilization.

It is now known that cellular and proteinaceous debris is present on applanation tonometers after use. Reusable tonometer prisms should be wiped with an alcohol swab and soaked in 0.5% hypochlorite solution for at least 5 minutes between each use. Following a case of adenovirus or after examination of a clinically infected patient the prism heads should be washed in detergent and water before soaking in hypochlorite solution. After a suspected case of adenovirus the area should be cleaned with the solution because alcohol does not destroy the virus. Two tonometers should be available at each slit lamp to allow time for adequate disinfection, and should not be shared between workstations to facilitate tracing in cases of bovine spongiform encephalopathy (BSE). After removing the item from the hypochlorite solution it should be thoroughly rinsed with sterile normal saline or

freshly boiled water at room temperature and then disinfected by the normal procedure because hypochlorite is not effective against some spores and cysts.

Tonometry may be performed using a noncontact tonometer, a tonopen or using disposable prisms, but none of these methods is as accurate as a Goldmann’s tonometer. Disposable prism heads should be used on all patients with known or suspected prion disease and for all patients at risk, such as those who have undergone neurosurgery, those suffering from a degenerative neurological disease of unknown cause or Creutzfeldt–Jacob disease (CJD) of any type, or with a family history of CJD; also recipients of pituitary-derived hormones.

Most soft contact lenses are now disposable or frequent replacement and the trial lens is from a sealed sterile container, and many manufacturers have agreed to supply practitioners with individual RGP lenses for a designated patient. These can be used as trial lenses that will be exchanged free of charge if adjustments are necessary, and disposed of if unsuitable.

Bovine spongiform encephalopathy

Serious problems have arisen in the UK because it has been suggested that BSE could be transmitted via trial contact lenses, although no such case has been reported. The infective agent is an abnormal prion (PrPsc), a protein molecule, which has been found in the brain and spinal tissue of diseased cattle. These prions accumulate in cells, particularly neurones. They resist degradation by enzymes and have a very long incubation period. They have been found in the retina and optic nerve of patients who have died of CJD and new vCJD. Prions differ from other infectious agents in that they do not contain either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). They adhere strongly, even to smooth metal and cannot be killed by any of the means currently available for use with contact lenses, even heat, and they cannot be completely removed from

References

instruments and devices by routine methods o decontamination.18

If diagnostic RGP fitting sets are necessary for complex patients they may be decontaminated in sodium hypochlorite solution (e.g. Menicon MeniLab 0.5%®) active chlorine, 5000 ppm fo 5 minutes, after which they must be thoroughly rinsed in sterile saline and then disinfected in th normal way.

Diagnostic contact lenses (e.g. gonioscopy lenses, three-mirror, and fundus lenses) should b wiped clean before they dry, and then immersed in the disinfection fluid that is normally used, becaus it is not yet known whether they are compatibl with hypochlorite solution. They should remain a one workstation. Cases have been recorded19 o CJD following corneal transplantation. The risk could be reduced by excluding any potentia donor with relevant symptoms.19,20

PROVISION OF SOLUTIONS

Consideration must be given to the cost of len care and maintenance. For those patients on low incomes in the UK there is provision, under th General Ophthalmic Service, to obtain a vouche towards the cost of their lenses, but this does no include the cost of solutions. There is a considerabl risk that such patients will not be able to afford full care for their lenses. The most serious compli cation of contact lens wear is corneal infection and this risk is minimized by cleaning and disin fecting the lens. Before prescribing lenses the prac titioner must ensure that adequate maintenanc can be afforded.

In hospitals that provide medically indicated contact lenses, a similar voucher is available There is provision by the National Health Servic for these patients to obtain their solutions from th hospital pharmacy. General practitioners are no allowed to prescribe contact lens solutions on th National Health Service, and to prevent infections full supplies should be provided by the hospital.

1.Ky W, Scherick K, Stenson S. Clinical survey of lens care in contact lens patients. CLAO J 1998;24:

216–219

2.Barlow M, Plank D, Stroud S, et al. The effectiveness of typical hand cleaning methods of hydrogel contac lenses ICLC 1994;21:232–236

3.Simmons PA, Edrington TB, Pfondevida C, et al. Comparison between evening and morning surfactant cleaning of hydrogel lenses. ICLC 1996;23:172–175.

4.Raali E, Vaatoranta-Lehtonen HH, Lehtonen OJ. Detachment of trophozoites of Acanthamoeba species from soft contact lenses with BEN22 detergent, BioSoak™, and Renu™ multipurpose solutions. CLAP J 2001;27:155–158.

5.Houlsby RD, Chavez G, et al. Microbiological evaluation of Miraflow. J Am Optical Assoc 1989; 60:592–595.

6.Penley CA, Willis SW, Sickler S. Comparative antimicrobial efficacy of soft and rigid gas permeable contact lens solutions against Acanthamoeba. CLAO J 1989;15:257–260.

7.Lebow K, Christensen B. Cleaning efficacy and patient comfort: a clinical comparison of two contact lens care systems. ICLC 1996;23:87–93.

8.Franklin VJ. Cleaning efficacy of single purpose surfactant cleaners and multipurpose solution (MPS). Contact Lens and Anterior Eye 1997; 20:63–68.

9.Kaplan EN, Grindel RE, Sosale A, Sack R. Residual hydrogen peroxide as a function of platinum disc age. CLAO J 1992;18:149–154.

10.Kiel JS. Protein removal from soft contact lens using disinfection/neutralisation with hydrogen peroxide/catalytic disc. Clin Ther 1993;15:30–35.

11.Soni PS, Horner DG, Ross J. Ocular response to lens care sysytems in adolescent soft contact lens wearers. Optom Vis Sci 1996;73:70–85.

12.Rosenthal RA, McDonald MM, Schlitzer RL, et al. Loss of bactericidal activity from contact lens storage solutions. CLAO J 1997;23:57–62.

13.Key J, Monnat K. Comparative disinfectant efficacy of two disinfecting solutions against Pseudomonas aeruginosa. CLAO J 1996;22:118–121.

14.Buck SL, Rosenthal RA, Abshire RL. Amoebicidal activity of a preserved contact lens multipurpose disinfecting solution compared

to a disinfection/neutralisation peroxide system. Contact Lens and Anterior Eye 1998;21:81–84.

15.Jones L, Jones D, Houlford M. Clinical comparison of three polyhexanide-preserved multipurpose contact lens solutions. Contact Lens and Anterior Eye 1997;20:23–30.

16.Chang JH, Ren HW, Petroll MW, et al. The appplication of in vivo confocal microscopy and tear LDH measurement in assessing corneal response to contact lens and contact lens solutions. Curr Eye Res 1999;19:171–181.

17.Collins M, Coulson J, Shirley V, Bruce A. Contamination of disinfection solution bottles used by contact lens wearers. CLAO J 1994;20:32–36.

18.Comoy E, Bonnevalle C, Métais A, et al. Désinfection de lentilles de contact rigides perméables vis-à-vis des prions. J Fr Ophthalmol 2003;26:233–239.

19.Hogan RN, Brown P, Heck E, Cavanagh HD. Risk of prion disease transmission from ocular tissue transplantation. Cornea 1999;18:2–11.

20.Herzberg L. Creutzfeldt-Jacob disease and corneal grafts. Med J Aust 1979;1:248.

CHAPTER CONTENTS

Good records 157 Instruction leaflets 158 Letters 159

Maintaining records 159 Confidentiality 159 Practitioner–patient relationship 159 Informed consent 159

Contact lens care 160 Consultations 160 Mailing lenses 161 Further reading 161

A record is the commitment, in writing, so as t furnish valid evidence of something having lega consequence. This chapter will review the record ing of any findings, the importance of correspon dence, confidentiality and legal requirements.

GOOD RECORDS

Good records must be legible. They are important clinically, if a condition is to be accurately monitored They improve communication. This is particularl important in large clinics where the patient may no always be seen by the same clinician. For this reaso abbreviations are best avoided, even when the appear to be in common use. They should be writ ten so that they show that the correct procedure were performed, and none omitted, and woul form a proper defense in the event of any legal pro ceedings. Good records are of benefit to the patien and can provide a basis for audit and research.

Inadequate records make it difficult to fin information, and create problems for colleague trying to understand the situation, and ma render you legally liable.

Aids to good record keeping

In court it will be assumed that only those proce dures recorded in the notes have been performed It is therefore important to have a routine tha ensures that nothing is forgotten. Some peopl prefer to use forms for notes to ensure that n examination is omitted. Others favor blank sheets which allow more space for any specific item.

Problem-orientated records

Problem-orientated record keeping is a system in which a list is made of the patient’s problems and all the history, physical findings and other data relevant to each problem are placed under that heading.

General information

Under this heading the patient’s name, address, sex and date of birth and telephone number should be recorded; also the family doctor’s name and address. These facts should be confirmed by the receptionist at each visit to correctly identify the patient and to ensure that mailed lenses reach the patient at the correct address. If lenses are to be sent by a method that requires a signature on delivery, the receptionist should make sure that someone will be present at that address or note an alternative address, usually the workplace. A contact telephone number must be recorded in case any problems arise, or an appointment needs to be changed. The name and address of the family doctor should be obtained to inform them of any findings. At the start of the consultation the practitioner should recheck the patient’s identity to ensure the correct notes are to hand.

Record data

Good records include a history of the current disease, the past ocular history, any family history of eye, or other relevant disease, and a note of the patient’s general health, in particular any allergies. Patients should specifically be asked whether they are on any treatment or tablets because they may state that their general health is good, and yet, on direct questioning, supply details of medication that they had not thought relevant.

Full details of the examination should be entered in the notes, and all findings, both normal and abnormal, must be recorded. Grading scales, diagrams and photographs or image capture techniques and measurements should be used whenever possible. An illustration of the site and size of a lesion is extremely helpful when monitoring a case, for follow up by another clinician, and for medicolegal reasons. A note must be made of any drops used during the examination. When the patient uses

doubtful techniques and does not conform to advised practices and, for example, licks lenses, uses a filthy case or lets lenses come into contact with tap water, these facts must be recorded.

The method of examination used should be recorded, for example whether vision was recorded with a full Snellen test type, or single letters, or a Sheridan–Gardiner test, or if tonometry was performed with an applanation or noncontact tonometer.

A record should be made of the prescription of any current spectacles and contact lenses.

At the end of the consultation a clear statement of the diagnosis of any medical or refractive condition should be made, with a record of any treatment prescribed, and any new spectacle or contact lens prescription. A note of the date of the next consultation should be entered in the record.

Record any tests performed, any oral or written instructions that were given, the name of any doctor to whom the patient was referred, and the details of lens care provided or treatment given. Finally a report should be made to the referring doctor or the family doctor and the patient’s optometrist or optician, when relevant.

Telephone calls

Details of any telephone conversation with you or your staff must be entered in the notes. The symptoms and reported signs are noted and any advice given is recorded. The note should be signed by the member of staff, and countersigned and dated by the practitioner to indicate that they are aware of the situation. Advice should be given only by a trained member of staff. If a contact lens practitioner is not available at the time, arrangements should be in place for the staff to contact the practitioner for advice or, preferably, so that the practitioner can return the telephone call.

INSTRUCTION LEAFLETS

Patient instruction leaflets may be produced by contact lens manufacturers, but may be supplemented by the practitioner’s own instructions. These should be written and include details of lens insertion and removal, how to recenter a lens that has decentered, how to care for the lens, the

wearing schedule and a list of dos and don’ts. Appropriate after-care appointments should be indicated and how to obtain help in an emergency.

LETTERS

Many practitioners now give copies of any letters that they write to referring clinicians or the family doctor to the patient.

MAINTAINING RECORDS

Any correspondence should be kept with the records together with visual field maps and photographs. If it is not possible to do this the location of any such investigations must be recorded in the notes and they should be easy to retrieve.

Writing should be legible. Never alter notes. Above all never erase anything. If something needs to be deleted cross it through and sign it. Never add anything at a later date that appears contemporaneous; write it, date it and sign it.

Take care when writing notes that they are not embarrassing to you or the patient. Humorous or derogatory comments or informal abbreviations (e.g. GOK, God only knows) are inappropriate, and care must be taken when recording relevant details that the patient might find offensive, such as dirty fingernails or a persistent smell of alcohol. You must be prepared to defend the relevance of these in court if necessary.

Storing records can create a problem because there is no legal limit to the time for which records be kept. The National Health Service normally keeps records for 8 years, and records relating to children are kept for 8 years after the age of 18. When the time comes to eliminate records they should be shredded or burned; records containing medical details should not be disposed of in normal office waste. The development of electronic patient records will reduce the amount of space required.

CONFIDENTIALITY

Records are confidential documents. They should be kept secure and not left lying where they are visible to others. Records should only be handled by members of staff who understand the confidential nature of the documents. Even appointment books

should not be available for public scrutiny. Th patient’s written consent must be obtained befor giving information to relatives or colleagues.

Ensure that staff understand the importance o confidentiality and are aware what advice the may and may not offer because you are responsi ble for their actions.

If it is necessary to fax information about patient ensure that the information is transmitte to a secure site that is not common to a variet of users, who may not be entitled to see suc information.

Any information transmitted to a third party b any means should have the written consent of th patient. This may sometimes pose a problem when a relative or other adult, meaning to help makes enquiries about a patient.

If data are stored on a computer, in a database you must be registered under the Data Protectio Act 1984, and passwords should be used to limi access and improve confidentiality. Screens shoul be sited so that other patients cannot view them. I confidential information is to be transmitted elec tronically it should be scrambled, so that onl those with the appropriate “key” can read it.

If any details, test results or photographs ar used for lectures or publication the patient shoul not be identifiable and consent should be obtaine for publication. If the patient has died, consen should be obtained from the relatives or executor of the estate.

PRACTITIONER–PATIENT RELATIONSHIP

The most important ingredient in a goo practitioner–patient relationship is good commu nication. Easy access to the clinician if the patient i unhappy and the assurance that every attempt wil be made to solve a difficulty is often all that i needed. Many patients do not realise that within warranty period an unsatisfactory lens can b exchanged at no charge. A telephone call t enquire whether all is well if there have been prob lems will often cause any ill-feeling to evaporate.

INFORMED CONSENT

A patient has the right to refuse any examination o procedure, and must be given sufficient informatio

to understand what is involved and why it is performed, the possible alternatives, and the consequences of refusal. For example warn the patient if drops are likely to sting, about the effect of dilating the pupil, and the effect of topical anesthesia. The patient should be advised if you are going to touch them, because without their consent this may constitute an assault. If the patient refuses consent for a procedure this must be recorded, the reason given for refusal, and that you have explained the possible consequences. Verbal consent is sufficient for most examinations, but written consent must be obtained for invasive procedures and investigations.

Children under 18 years of age must have parental consent, and parents should accompany them to the consultation. Drops should not be instilled in the absence of a responsible adult. It is also advisable to have a parent present with 16–18 year olds during fitting and teaching visits because the risks and costs involved must be understood by the parent. Some parents are very casual and will send an unaccompanied teenager for a consultation.

Forms used to obtain consent must be written in plain, easily understood language, avoiding technical terms.

Regarding contact lenses the risks and benefits of lens wear must be explained, any possible alternatives should be explored, and if the chances of meeting the patient’s expectations are poor, the patient should be advised of this. The patient should understand that the type of lens chosen should be determined by your findings, but that their wishes will be taken into consideration.

The patient should understand that all contact lenses carry a slightly increased risk of infection, but that the most risk is associated with extended wear, although silicone hydrogel lenses are believed to reduce this risk, and they need to take any symptoms and signs very seriously. Unless absolutely necessary an extended-wear lens should not be fitted to an only eye. It should only be undertaken after all other avenues have been explored and the seriousness of the problem must be clearly understood by the patient. Facilities must be available to see the patient immediately any problems arise, and patients must be prepared to attend as soon as they have symptoms.

Specific written instructions, with emergency telephone numbers, must be given to all

extended-wear patients. Similar advice should be given to therapeutic lens wearers, who are often older and are not keen to commence lens wear.

Those needing toric lenses should understand the need for an increased number of visits and the higher cost involved with this type of lens.

For patients fitted with monovision it is necessary to explain that this is a compromise, and that there may be problems of fusion and the reduction in depth perception, together with the risks of flare and glare, and the variation with altered lighting conditions. All presbyopes need to understand the role of spectacles for them.

If there are language difficulties it is important that a translator is present, and if the patient is registered deaf, a person who can sign may need to be present. At all times the clinician should be aware of the needs of those with disabilities and ensure that by 2004 access to the practice is appropriate, and suitable toilet facilities are available to meet the requirements of the Disabilities Act.

CONTACT LENS CARE

Only approved solutions should be used. The patient instruction leaflet should contain information on how to care for the lens. The use of the solution should be demonstrated to the patient and an appropriate care system selected for the individual patient. The solution selected, and any changes to this, should be recorded in the notes. At each visit the system being used by the patient should be checked because they may have changed solutions because of difficulty in obtaining the recommended system, or on the recommendation of a friend. Particular solutions for gas-permeable lenses are often difficult to find because retail outlets devote more shelf space to those for soft lenses because these form the bulk of the contact lens market, but it should be possible to order them because the retailer can obtain small quantities.

CONSULTATIONS

The advised interval for the next visit should be noted. If the patient fails to attend, cancels or postpones a visit, this should also be noted.

All patients should have access to an emergency number at all times, 7 days a week, 24 hours a day. This is particularly important if extendedwear lenses are fitted.

MAILING LENSES

Occasionally patients cannot attend the practice before their supply of lenses run out and they

Further reading

request lenses by post. These should only b supplied to patients who are registered with th practice and who have had regular follow up A small supply may then be sent, providin that the patient agrees to an examination i the near future. If patients fail to attend an request further lenses then it should be entere in the notes, with instructions not to send mor lenses.

Blakeney S. Postscript: Informed consent – The UK perspective. J Br Contact Lens Assoc 1994;17:105–106.

Harknett TL. Clinical records in contact lens practice. J Br Contact Lens Assoc 1995;18:41–47.

Harris MG. Informed consent for contact lens patients. J Br Contact Lens Assoc 1994;17:119–125.