Assessment of Patient Suitability for Contact Lenses

Most contact lenses fitted nowadays are soft as there is such a wide range of parameters available, including toric and multifocal, and made in materials that can be used for all wear modalities. This allows more patients with differing requirements to be fitted with contact lenses. Rigid gas permeable (RGP) materials and scleral lenses are now mainly considered for eyes with pathological or abnormal conditions unsuited to soft contact lenses, although many patients have successfully worn these lenses for years. Usage varies between different countries, and there is increasing use in areas such as orthokeratology (see Chapter 15, Chapter 20, Chapter 21, Chapter 22, Chapter 23 ).

Limitations still exist in the types of lenses available as well as in the suitability of the prospective wearers, and in addition, the contact lens practitioner has to assess the best form of lens and material to satisfy the requirements. There are many factors to consider when assessing patients, and careful selection benefits both patient and practitioner by avoiding time wasted in attempting to fit unsuitable patients or in fitting patients with unsuitable lenses.

Almost any ocular contour can be fitted with a contact lens as long as the patient is motivated and there are no contraindications. Indeed, certain pathological and abnormal conditions of the eye and adnexa are a definite indication for contact lenses (e.g. keratoconus).

Issues Relating to Lens Wear

So that the patient has the opportunity to reject lenses before being placed under any obligation, his or her attention should be drawn to the following.

Time taken for fitting

This varies and can depend on the skill of the practitioner and the type of lens to be fitted. Including tuition of lens handling, some 2–3 hours or more may be needed with the practitioner and/or optometric assistant. Numerous visits to the practitioner may be necessary and, if the fitting proves complicated, a longer time may be involved.

Tolerance trials can add to the time spent by both patient and practitioner. The desirable minimum for a tolerance trial is about 4 hours, but some may need to be as long as 2 weeks. When fitting lenses for extended or continuous wear, it is advisable to start with a daily wear schedule for 2–3 weeks to determine suitability before converting to overnight wear. This may be considered as a tolerance test for extended wear and also enables the essential practice of inserting and removing lenses (see also Chapters 12 and 15 ). A further examination is essential on the first morning after overnight wear.

Initial discomfort – physical and visual

Soft contact lenses are usually comfortable on insertion, and most patients may comment that they feel little or nothing. However, patients may be unprepared for the initial difficulties with lenses and should be warned about corneal and lid sensation, photophobia, flare and after-wear blur with spectacles (more noticeable with rigid lenses than with soft). However, these aspects should not be overly stressed, or the patient may be too nervous to continue!

Gradual wearing procedure

Soft lenses do not usually require a buildup time, but as mentioned above, extended- or continuous-wear lenses require a period of daily wear before commencing overnight use. Wearing time with rigid lenses should be built up gradually.

Special storage

Contact lenses must be handled and stored carefully and hygienically. Because of their wetting and hydration properties and the danger of transferring harmful organisms onto the eye, specific solutions are used during handling and storage. Patients must be warned of the risks and advised which solutions are suitable for their lenses and which may come into contact with the eye.

Daily disposable lenses do not require cleaning and soaking solutions, although even with these, hand hygiene is essential and sterile saline and/or rewetting drops may be necessary (see Chapter 10 ).

Extra hygiene

Patients often fail to maintain good hygiene. Unlike spectacles, rigorous care is important throughout the lens life.

Hygiene required when wearing lenses includes the following:

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Wash hands thoroughly (for further information, please see https://expertconsult.inkling.com/ ).
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Check the lenses daily to avoid wearing damaged lenses.
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Avoid contamination of the lenses with make-up and, if necessary, use special types of make-up. Eye make-up should be put on after lenses have been inserted. It can cause potentially serious infection ( , ) and can become embedded in the conjunctiva, causing long-term discomfort and excessive lacrimation ( , , ). Patients should be advised about the safest methods of using make-up with contact lenses, for example https://www.acuvue.co.uk/life-with-lenses/beauty-and-make-up-contact-lenses (see also Chapters 5 , 15 and 24 ).

Cleaning and disinfecting unfortunately add to the time and cost of lens maintenance, and for patients who are unwilling or unable to look after their contact lenses properly, daily disposable lenses should be considered or the patient advised to continue with spectacles.

Stringent aftercare

Regular aftercare is necessary at regular intervals, but minor emergencies may still occur in between visits, so patients should be educated on the signs and symptoms to be aware of that warrant practitioner investigation. Follow-up at intervals of no greater than one year is advisable so that any changes can be noted and advice given accordingly. Some patients require more frequent aftercare checks because of recurrent symptoms or pathology, or type of lens. New wearers should have a checkup soon after commencing lens wear (less than 1 month) and again after around 6 months.

The aftercare check is, of necessity, longer and more detailed than that given to a normal spectacle wearer.

Fitting children

Children can take extra time, and parents need to be advised of this (see Chapter 24 ). It is especially important that children are dealt with in an unhurried and reassuring fashion. If less than 16 years, the child should be fitted in the presence of a parent or guardian, both to give the child reassurance and to demonstrate lens handling to the parent who may be required to carry this out.

At the first visit, besides the preliminary examination and measurements, it may be enough to insert one lens and leave proper fitting for a further visit. A child may require a lot of time to perfect insertion and removal techniques, a few short visits being better than one long one, although children who are well-motivated or whose parents wear contact lenses may learn quickly, often managing better than adults.

With the increasing prevalence of myopia, there is likely to be an increasing use of contact lenses for children as a means of myopia control (see Chapter 28 ).

Lack of protection from foreign bodies

Spectacle wearers who transfer to contact lenses miss the protection afforded by their spectacles initially and should be warned of possible difficulties in windy or dusty atmospheres.

Sunglasses can increase the comfort for someone adapting to rigid lens wear for the first time.

Cost of lenses, examination fees and accessories

Patients need to be advised of initial fees from the start of fitting and of the final fees once the type of lens has been decided. The fitting fee should include:

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the initial fitting fee
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one year of aftercare
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information about how much care they should expect to receive
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other costs such as solutions, accessories and extra appointments above a certain number.

Indications and Contraindications for Contact Lens Wearing

These may be considered broadly under three headings:

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psychological influences
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pathological, anatomical and physiological factors
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personal and external factors.

Some overlap between the three is inevitable.

It is useful to consider these factors during aftercare of contact lens wearers (see Chapters 16 and 17 ), and patients should not necessarily be rejected if they fail in one particular area.

Psychological influences

suggested that factors such as motivation, coping abilities, willingness to set realistic goals and the degree of tolerance to pain and frustration should be considered as indicators of potential success with contact lens wear.

A small study by indicated that extroverted, well-adjusted, stable people were more likely to successfully adapt to contact lenses than anxious, introverted people. In addition, found that a practitioner's interpersonal skills and knowledge affected the patient's confidence, motivation and success in contact lenses. Practitioners need to keep all these points in mind when assessing patient suitability and also make their patients aware of the differences between the fitting and wearing of spectacles and that of contact lenses to avoid subsequent disillusionment.

From the legal standpoint, patients should be issued a printed leaflet or electronic information containing general facts about contact lenses as well as specific instructions on care and maintenance, lens replacement and wear time and hygiene requirements specific to their situation. Many of these leaflets are readily available from contact lens companies and related organisations and are also found on websites including further material available at https://expertconsult.inkling.com/ . This also helps patients who are not fully attentive at the initial consultation or forget what they have been told (see also Chapter 31 ). Both verbal and written information given to patients should be noted in the records.

Fear of Lenses

There is a natural fear of having anything placed on the eye. A practitioner who inspires confidence is usually able to help a patient overcome this quickly (see also Chapter 15 ).

Contact lenses can cause corneal abrasion from:

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foreign bodies beneath them
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adherent deposits
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damaged lens edge
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trauma from the edge of a rigid lens during insertion or removal
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fingernails.

Usually the ensuing discomfort is minimal, but patients have been known to reject lens wear as a result.

There are many indications for contact lenses which have a psychological background:

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Safety: Fear of injury from spectacles during sport. Contact lenses can afford some protection from a blow that might have resulted in both external and internal ocular damage. However, special safety spectacles or goggles for certain sports are advisable to provide better protection and should be worn over contact lenses.
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Security and clarity of vision: Spectacles may steam up or become coated with spray when cycling or horse riding, and contact lenses provide a distinct advantage.
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Cosmetic reasons: Changing from spectacles, especially with thick lenses, can result in a marked cosmetic improvement when contact lenses are fitted. This can lead to a marked improvement in confidence ( ). To some patients, spectacles are an advertisement of a personal disability which is relieved by wearing contact lenses. Similar psychological benefits occur when a disfigured eye is fitted with a prosthetic lens to give a normal appearance (see Chapter 25 ).

Children (see Chapter 24 )

If children are keen to wear contact lenses, they usually adapt well, but they should not be forced to wear lenses just because the parents are keen. Fitting lenses can be traumatic if it is carried out against the child's will.

Pathological, anatomical and physiological factors

Nontolerance of Spectacles

Spectacles may not be tolerated due to:

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trauma
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skin disease
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allergies
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psychological problems (see above)
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absence of one or both external ears.

Contact lenses may then be suitable, although they may exacerbate some skin diseases such as epidermolysis bullosa (see Chapter 24 ), a rare inherited skin disease in which blisters appear at sites of mechanical trauma.

People who ‘cannot bear’ spectacles may not tolerate the difficulties of contact lenses and may be better advised to try a lighter-weight, nonallergic spectacle frame instead.

Pathological Problems Found During Examination

Patients with certain pathological conditions may be referred by a medical practitioner for contact lenses. If pathology is discovered during the course of the examination, a medical opinion may be necessary before fitting. A few points are considered here.

General Health Conditions

General debility.

Tolerance of contact lenses is likely to be poor unless the general health is good.

Diabetes.

The clinical response of the diabetic eye to current soft contact lenses does not differ appreciably from that of the nondiabetic eye, and found no increase in complications in diabetic contact lens wearers compared to wearers without diabetes possibly because modern materials provide a healthier ocular environment. However, extended-wear lenses should be avoided. RGP corneal lenses were more commonly fitted in the past due to the perceived lower risk of infection, but when these are fitted, care is needed to prevent ‘3 and 9 o'clock’ corneal desiccation with its attendant risks. Reduced wearing schedules and frequent aftercare should be considered.

and described some of the potential difficulties in fitting diabetics. These include:

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blepharitis
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dry eye
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epithelial fragility and reduced rate of healing
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keratitis
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unstable refraction
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higher risk of bacterial and fungal infections.

Hyperthyroidism.

The disturbed metabolism, which results in exophthalmos and lack of blinking, can make contact lens wear difficult as there is likely to be insufficient tear flow. Dry eye disease may also occur, causing difficulties in lens wear.

Chronic Catarrh and Sinusitis.

Patients with these conditions are at greater risk of ocular infection if corneal abrasions occur. The associated mucus in the tears also causes visual problems and deposits on the lens surfaces. In rigid lens wearers, strings of mucus may collect behind the lens, and if the nasolacrimal drainage channels become blocked, epiphora can result, which is exacerbated by contact lens wear.

Herpes Simplex.

Cold sores on the mouth may be transferred to the eye, either from licking the lenses or by hand. Corneal dendritic ulcers from the herpes simplex virus frequently recur, and contact lens wear must be discontinued. Increased recurrence rates have also been shown for contact lens wearers ( ). Once the virus becomes quiescent, it may be possible to refit RGP lenses, which can improve visual acuity, but this should be resumed only on medical advice.

Skin Conditions.

Where there are infections of the eye or its adnexa, soft lenses should be fitted only under medical supervision because of the likelihood of material contamination and the risk of extending the infection. RGP lenses may be a safer option.

Extra care and prolonged tolerance trials should be undertaken during fitting. If the skin condition worsens or the ocular involvement becomes evident, contact lenses may have to be abandoned. The following are typical of such conditions:

Acne vulgaris

(see also Chapter 24 ) occurs around the age of puberty but is not markedly aggravated by contact lens wear. Greasing and frothing of tears may prevent satisfactory wear of any lens type. Daily disposables are an option but lens surfaces rapidly deteriorate due to contamination by sebum from the eyelids, so whole-day wear may not be possible (see ‘Lid hygiene’, Chapter 16 p. 332 ). Ocular lubricants can help extend the number of hours of wear. Rigid lens wear can be improved using lens solutions containing polyvinyl alcohol to minimise greasing. Corneal lenses fitted within the palpebral aperture reduce the massaging effect on the lids, avoiding the increased output of sebum.

Acne rosacea

is accentuated as the foreign body reaction to lenses increases blood vessel dilatation of the skin on the face and conjunctiva. Punctate keratitis associated with the condition may be exacerbated by contact lenses wear; however, in the absence of keratitis, daily wear silicone hydrogel, high-water-content soft or RGP corneal lenses may be tolerated.

Oral treatment for acne can cause a variety of ocular side effects and reduce tolerance to contact lens wear.

Atopic eczema – associated with asthma and hay fever

(see Ocular allergies and Atopy below). Contact lenses, especially rigid lenses, may cause an urticarial reaction. Soft lens surfaces may degrade rapidly due to excessive protein deposits.

A low wetting angle is more important than oxygen permeability in RGP lens materials. Fluoropolymers (see Chapters 2 and 9 ) which have a high Dk and also wet well can be recommended for such patients, although careful temperature-controlled manufacture is necessary to ensure good surfaces. Excess polishing creates a high temperature and can reduce the surface wetting properties. Polymethylmethacrylate, although rarely fitted now, has good wetting properties, and this may still be the best material for some patients, provided that precautions are taken to ensure an adequate oxygen supply to the cornea. Lid irritation from rigid lens edges should be avoided by fitting with minimum peripheral clearance and as large a lens diameter as is practicable, with thin (0.12 mm radial edge thickness) and well-rounded edges (see Chapter 9 ).

Epidermolysis bullosa

may necessitate the correction of any refractive error with high-water-content soft or daily wear silicone hydrogel lenses (see Chapter 24 ). Other types of lenses are likely to exacerbate the effects of the condition on the eye ( ). These depend on severity and range from mild blepharitis and conjunctivitis to pronounced vesicle formation and epithelial sloughing.

Keratoconjunctivitis sicca (Sjögren's syndrome) – associated with rheumatoid arthritis.

A lack of tear secretion and filamentary keratitis are common (see Fig. 26.5 ). The lens of choice is a high-Dk rigid corneal lens ( ) or scleral lens ( , ) used in conjunction with artificial tear supplements and, if necessary, insertion of punctal plugs ( and see Chapter 5 ). Low-water-content silicone hydrogel lenses are used successfully as bandage contact lenses for those with severe dry eye symptoms ( ). The lenses should be used together with regular instillation of saline or artificial tears.

Sealed RGP scleral lenses used with a suitable artificial tear solution (see Chapter 14 ) also prove satisfactory and assist in protecting the cornea.

Psoriasis

may be associated with a nervous disposition, and although not directly associated, fitting contact lenses may lead to a worsening of symptoms. For this reason soft lenses are likely to perform best.

Seborrhoeic eczema.

The condition manifests as dandruff and blepharitis (see Fig. 5.4d ), and contact lens wear may exacerbate the problem. In the presence of blepharitis, contact lenses are contraindicated (see Chapter 16 ) as there is a risk of staphylococcal keratoconjunctivitis.

Xerophthalmia (vitamin A deficiency), congenital ichthyosis (dry skin) and sarcoidosis.

The approach to these conditions is similar to that of keratoconjunctivitis sicca. Success is possible with all options but more likely with low-water-content silicone hydrogel lenses or high-Dk RGP corneal lenses.

reported a case of keratomalacia – the corneal manifestation of xerophthalmia – in a patient with food phobias whose diet lacked vitamin A. It would therefore seem wise to question all dry eyed patients about possible dietary causes of their symptoms (see ‘ Diet ’, below, p. 129 ). Artificial teardrops containing vitamin A may be beneficial.

Ocular conditions

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