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Marin Eye Care: Good Candidate for Contacts

Care Process

Pre-Fitting Considerations

• Indications
• Some factors that suggest whether a patient is a good candidate for contact lens wear involve optical, physiologic, and cosmetic considerations. The following indications should be considered in the evaluation of a patient's potential for successful contact lens use (See also Table 1 in the original guideline).
• Optical Factors - Contact lenses improve visual function by neutralizing ametropia, or minimizing distortion, especially when the patient suffers from more than a modest spherical refractive error or astigmatism, regular or irregular. Myopic patients benefit from the increased magnification provided by contact lenses, compared with their spectacle corrections. The reverse is true for both hyperopic and aphakic patients; however, such patients benefit from enhanced fields of vision with contact lenses. For anisometropic patients, aniseikonia and prismatic effects may be reduced or eliminated with contact lens wear.
• Presbyopia - Although many patients with presbyopia wear contact lenses, presbyopia is not specifically an indication for contact lens correction. Presbyopic patients may wear distance contact lenses and use additional reading spectacles of various types to address their presbyopia. Alternatively, presbyopes (especially emerging presbyopes) often successfully use what has been termed "monovision" correction in which one eye wears a contact lens to correct for distance vision and the other wears a contact lens to correct for near vision. Various bifocal contact lenses are available in either rigid gas permeable or hydrogel materials.
• Therapeutic Potential - Contact lenses have been used to manage both aphakia and binocular vision problems, especially accommodative esotropia and convergence excess. Contact lenses, particularly rigid contact lenses, can optically smooth an anterior corneal surface made irregular by disease (e.g., keratoconus or corneal microbial infection), trauma, or surgery (e.g., penetrating keratoplasty or ineffective refractive surgery). Hydrogel lenses are used as ophthalmic bandages following corneal trauma or refractive corneal surgery. Rigid contact lenses also have been used to manage or reduce myopia. Both clear and tinted rigid and soft contact lenses have been used for treatment by occlusion in cases of diplopia and amblyopia.
• Cosmetic Effect
• Correcting ametropia by placing a lens directly on the corneal surface improves cosmesis by eliminating the need for a spectacle frame and often unattractive corrective ophthalmic lenses. Some patients elect to wear colored contact lenses simply to change the appearance of their eye color. Opaque contact lenses also may be used for their prosthetic effect (e.g., masking an unattractive corneal scar or damaged iris or providing an artificial pupil in the treatment of aniridia).

• Cautions
• Any patient whose clinical situation suggests increased risk of ocular infection or inflammation, but who insists on cosmetic contact lens fitting, should give formal informed consent before the clinician provides contact lenses. Several factors could limit a patient's suitability for contact lens wear, as discussed below (See also Table 2 in the original guideline).

• Ocular Considerations

Placing the lens directly in the precorneal tear film increases the risk of tissue compromise. Contact lens use should therefore be approached cautiously for either the monocular patient (because of risk to the patient's only useful eye) or for the patient who is engaged in an avocation or vocation with exposure to a particularly dirty or dry environment. Such individuals may be advised to wear protective spectacles.

A mildly abnormal tear layer, whether insufficient in volume or of poor quality, decreases the likelihood of successful and asymptomatic contact lens wear, but contact lenses should be considered in the context of patient motivation and other relevant indications. Some forms of abnormal tear layers can be treated with supplemental artificial tear drops or ointments and mechanical or thermal occlusion of the nasolacrimal punctae (See "Dry Eye" under "Care Process-Contact Lens Examination and Fitting-Special Concerns" [Section IIB4b] in the original guideline document).

• Systemic Considerations

• Noncompliant Patients

• Types of Contact Lenses
• Hydrogel Lenses

• Rigid Lenses

• Scleral or haptic high-Dk (oxygen permeability) rigid gas permeable (or even polymethyl methacrylate) contact lenses can be used in the management of keratoconus or other therapeutic cases such as ocular cicatricial pemphigoid or Stevens-Johnson Syndrome.

• Hybrid and Silicone Lenses - Though not in common use, such lenses are extremely helpful in rare cases of regular or irregular corneal astigmatism (including keratoconus) or aphakia.

• See the original guideline for a detailed description of these types of contact lenses.

Contact Lens Examination and Fitting

• Note: Refer to the Optometric Clinical Practice Guideline for the Comprehensive Adult Eye and Vision Examination (St. Louis [MO]: American Optometric Association [AOA]; 1994. 16 p. [Optometric clinical practice guideline; no. 1]).

Fitting Different Types of Contact Lenses

Although not all clinicians always use a diagnostic evaluation of trial lenses prior to ordering the contact lens, such a process, while both somewhat labor- and time-intensive, allows clinicians and patients to gain a better perspective on the anticipated performance, including both optical and physical/physiological tolerance, of the contact lenses ordered. Some clinicians employ topical corneal anesthesia to ease initial rigid gas permeable fitting in the office. Carefully applied, this technique may be useful during the initial fitting or instruction phase of contact lens care without giving the patient a false sense of tolerance. To avoid complications of abuse, topical anesthetics should not be prescribed or dispensed to a patient.

See the original guideline document for more specific information on fitting of the following types of contact lenses:

• Spherical Hydrogel Lenses
• Toric Hydrogel Lenses
• Spherical Rigid Lenses
• Toric Rigid Lenses
• Determination of Optical Power

Special Design Features

• Lenticular Edge Modification
• Prism and Truncation
• Fenestrations
• Blending

Special Concerns

Dispensing Lenses and Patient Education

The patient, or a parent or guardian, should be trained in lens care, maintenance, and handling. The importance of proper hygiene, compliance with contact lens care techniques, and appropriate follow-up under professional supervision should be stressed. Warnings, precautions, and directions for use of a contact lens are found in the patient information booklet available upon request from the lens manufacturer. Information directed to the eye care practitioner is found in the package insert or in the professional fitting guide. Other extensive literature on the proper care of contact lenses is available.

The patient should be taught to perform the following steps in the care and handling of a contact lens:

• Wash hands.
• Clean each contact lens by gently rubbing and thoroughly rinsing with an appropriate solution.
• Store and disinfect contact lenses in fresh appropriate solution for an appropriate time interval in a clean case until reinsertion in the eyes.
• Reclean and resoak contact lenses periodically and again preceding wear if there is an interruption in contact lens wear for any reason.
• Discussion of these procedures and warnings should be provided in writing and documented in the patient's record.
• Professional follow-up care should be scheduled.

Progress Evaluations

The clinician should recommend additional visits whenever the contact lens patient experiences an unexpected problem in vision or ocular condition. Emergency services should be available 24 hours a day, every day of the year, through the practitioner's practice or through eye care, health care, or emergency room facilities.

Progress evaluations, planned or unplanned, should follow the "SOAP" format. The clinician should begin by obtaining a Subjective history of both contact lens wear and other concerns. The clinician should then evaluate Objective clinical findings, such as visual acuities and over-refraction results. Appropriate confrontation tests and gross observation of the eyes and adnexa should be performed at this time, followed by biomicroscopic evaluation of the lenses on the eyes and of the patient's anterior ocular segments, often with the assistance of diagnostic dyes. The clinician should periodically evaluate the corneal surface by keratometry or videokeratography/topography. Additional examinations and investigations may also be indicated. For example, a contact lens-wearing patient who complains of a sudden onset of "floaters" in one eye should be seen immediately to evaluate for possible retinal detachment. In cases of reduced vision that cannot be attributed to lens power or contact lens optical quality, ocular media and retinal assessments are indicated. The clinician can then effectively Assess the situation and Plan appropriate management steps. The clinician should monitor refraction and general ophthalmic health at whatever normal schedule is appropriate for the patient's situation.

During progress evaluations of rigid gas permeable wearers, the prescribed parameters of the contact lenses should be periodically verified and the lenses reconditioned (polished) to reduce both soilage and scratches when necessary. When contact lenses are found to have been damaged or changed during use (e.g., any cracks or edge chips, and/or warpage or flattening/steepening of the back central optical radius greater than 0.1 mm), replacement of the contact lens is advised.

Management of Complications Associated with Contact Lens Wear

Table 1. Clinical Grading of Response to Contact Lens Wear: Proposed Interpretation and Clinical Approach

Note: This is an ordinal and not integer scale.

• Ordinal scaling implies that a Grade 3 response is greater than a Grade 2; however, the interval between Grades 1 and 2 may not be the same as the interval between Grades 2 and 3.

General Considerations

Contact lens soilage or solution reactions, and their secondary complications, can be avoided by use of "disposable" contact lenses. These hydrogel lenses are manufactured through molding technology that maintains high-quality design standards and has reduced the cost of lenses to the extent that daily replacement of lenses has become a practical option for some patients. Prescribing disposable contact lenses has the advantage of maximizing patient convenience while minimizing the possibility of solution reactions. Rigid gas permeable contact lenses can usually be reconditioned by polishing and cleaning, but they sometimes become warped, scratched, or soiled to an extent that is beyond office rehabilitation.

Most complications of contact lens wear increase in both prevalence and severity when patients wear them on an extended or continuous basis. Therefore, restricting contact lens use to daily wear whenever possible is a means of minimizing the occurrence of these complications.

Many of the complications of contact lens wear are also accompanied, and in some cases at least partially caused, by lid diseases such as blepharitis, meibomian gland dysfunction, and dry eye. Treatment of underlying lid disease and dry eye by improving lid hygiene, the use of artificial tear drops (often in unpreserved unit doses), punctal occlusion, and appropriate antibiotic treatment, either locally or systemically, is helpful in minimizing many of the complications of contact lens wear.

Many of the complications of contact lens wear can be treated effectively by temporary discontinuation of contact lens wear. Reversal of inflammatory lid and conjunctival reactions and solution sensitivities, collapse of mild forms of corneal neovascularization, and healing of corneal epitheliopathies often occur without additional treatment. The use of adjunctive medical therapy, consisting of artificial tears, nonsteroidal anti-inflammatory drugs (NSAIDs), mast cell stabilizers, antibiotics, and occasionally even steroid drops, should be considered.

Special precautions should be taken to avoid the spread of infection from one patient to another in the practitioner's office. These measures should include appropriate cleaning and the disinfection of diagnostic contact lenses and adjunctive equipment, especially tonometers. Disinfection must be performed by a method approved by the U.S. Centers for Disease Control and Prevention (CDC).

Noninfectious Complications

Another common complication of contact lens wear is hypoxia, which induces changes at all corneal layers. These changes include microcysts and microcystic edema (MCE); central circular clouding (CCC); pseudodendritic edematous corneal formations (ECF); decreased epithelial mitosis, sensitivity and adhesion; changes in stromal thickness, acidosis, and striae; and endothelial blebs and polymegethism. In a postulated corneal exhaustion syndrome (CES), previously successful long-term contact lens wearers suddenly become intolerant of additional contact lens wear.

Superficial corneal pannus is associated with either chronic hypoxia or chronic 3/9 epithelial desiccation (rigid contact lenses). Secondary intracorneal hemorrhages can occur. Deep stromal neovascularization is a very rare complication.

Contact lens wear can lead to distortion and warpage of the corneal surface, which results in "spectacle blur" or a reversible loss of good spectacle acuity immediately following contact lens wear. Clinicians also often observe "dimple veil" epithelial depressions from bubbles of air trapped between contact lenses and the ocular surface.

True epithelial "staining" represents some epithelial cell layer disruption, which can progress to occasional erosions and even abrasions. Etiological factors may be obvious -- chemical trauma (e.g., solution reactions), mechanical trauma (e.g., damaged contact lenses, foreign bodies trapped between the contact lens and the eye), or superior epithelial arcuate lesion (SEAL or "epithelial splitting") -- or obscure. Some brands of contact lenses cause distinctive staining patterns without progressing. Clinicians should consider either keratoconus or Cogan's microcystic-map-dot-fingerprint dystrophy in any patient who presents with an abrasion without a clear-cut historical etiology (see Figure 1 in the Appendix to the original guideline).

Corneal infiltrates, both round and dendritic, may be signs of solution sensitivity, true corneal microbial infection, or even unrelated complications. The clinician should always be alert to the possibility of herpetic or Acanthamoeba infection masquerading as a more benign contact lens complication etiology (see Figure 2 in the Appendix to the original guideline).

Documented lid reactions include allergic responses such as giant papillary conjunctivitis (GPC) or ptosis. The conjunctiva is also subject to many types of toxic and allergic reactions, some totally and others partially, due to the use of contact lenses and their care solutions. The clinician should always be careful to consider masquerade syndromes (e.g., drug abuse or herpetic disease).

The clinical challenge is often to maintain contact lens wear in the face of five specific types of noninfectious complications, as discussed in the following paragraphs.

Solution Reactions

When the clinician suspects such a reaction, contact lens wear should be discontinued, and appropriate treatment and professional observation should be initiated. After reversal of the reaction, the clinician may initially try substituting one product or class of product for another. When this measure fails, hydrogel contact lens wearers may be fitted with daily disposable contact lenses to eliminate all solution issues. Rigid gas permeable wearers can use aerosol-packaged nonpreserved saline to rinse their lenses copiously prior to insertion. For fear of an Acanthamoeba infection, the use of tap water or fresh water rinses is discouraged. If water is utilized for rinsing rigid gas permeables, an additional rinse with sterile saline or conditioning solution is recommended (see Figure 3 in the Appendix to the original guideline).

Hypoxia

When there is clear evidence of hypoxic corneal changes (e.g., epithelial or stromal edema, corneal pannus greater than approximately 2 mm unrelated to 3/9 stain), conjunctival changes, or suspected corneal exhaustion syndrome, the clinician should adjust the contact lens wear schedule or change the contact lens material or design to enhance the availability of oxygen to the anterior corneal surface (see Figure 4 in the Appendix to the original guideline).

Three O'clock and Nine O'clock Staining

The condition of the patient's lids/meibomian glands and tear layers often contributes to 3/9 staining and should also be addressed (as discussed previously). Lens position and wearing time should be managed. When all attempts to solve the problem with rigid gas permeables are unsuccessful, and when there are no contraindications, the prescription of hydrogel contact lenses may also be considered (see Figure 5 in the Appendix to the original guideline).

Corneal Abrasion

Treatment consists of first ruling out infection and temporarily discontinuing contact lens wear. Some clinicians believe in prophylactic antibiotic treatment, while others prefer to withhold antibiotics unless infection is suspected or proven. To decrease the risk of precipitating or enhancing a microbial corneal infection, the clinician should neither patch nor use topical steroids to treat a contact lens-associated abrasion (see Section 3a "Infectious Complications--Bacterial Infections," below). Close professional supervision is prudent until the epithelial defect has closed and the etiology of the abrasion should be considered before contact lens wear is resumed. For example, when the cause of the abrasion appears to be the patient's failure to insert or remove the contact lenses properly, reinstruction in these procedures should precede contact lens redispensing. Management of the patient with repeated apical corneal abrasions, in particular the patient with keratoconus, may require refitting of the contact lenses with steeper back central optical radius or the use of piggyback contact lens systems (see Figure 6 in the Appendix to the original guideline).

Giant Papillary Conjunctivitis

If at all possible, the patient diagnosed with giant papillary conjunctivitis should first discontinue contact lens wear until he or she is symptom (itching) free and the signs (mucus, inflammatory tarsal conjunctival papillae) are subsiding. Contact lens wear may then be resumed cautiously, with improved contact lens cleaning (e.g., more frequent, increased use of enzyme cleaner). The use of peroxide disinfection or daily-disposable contact lenses is helpful for hydrogel wearers. Often it is also helpful to change the contact lens design from hydrogel to rigid gas permeable or vice-versa, or at least the edge design. Finally, topical mast cell-stabilizing agents, nonsteroidal anti-inflammatory drugs, antihistamines, and occasionally steroids (with caution to minimize the risk of secondary ocular infection, glaucoma, or cataract) may be prescribed adjunctively for those patients who on maximal nonmedical treatment still show signs or symptoms and for whom contact lens wear cannot be discontinued (e.g., those with keratoconus) (see Figure 7 in the Appendix to the original guideline).

Infectious Complications

Corneal infection is a potentially blinding disease, but fortunately, it is rarely encountered when the use of contact lenses is restricted to daily wear with good care and hygiene. When suspected or diagnosed, such lesions deserve immediate aggressive treatment and management. Whenever any of the signs or symptoms of corneal infection occur, contact lens wear should be discontinued in both eyes to decrease the potential for bilateral disease.

Bacterial Infections

Poor compliance with appropriate contact lens care procedures also appears to be a major risk factor for microbial infection (especially Acanthamoeba, as discussed in the next section).

Traditional management of corneal ulcers and severe infections begins with the acquisition of cultures on blood and chocolate agars, on Sabouraud's medium (for fungi), or on thioglycolate medium (for anaerobes), with Gram-staining of smears for microscopic evaluation. A sterilized Kimura spatula is used to acquire material for these laboratory investigations by scraping the leading edge of the corneal ulcer. Aggressive topical treatment should begin with dual therapy: specially prepared fortified topical aminoglycosides (e.g., gentamicin, tobramycin, amikacin) to attack Gram-negative bacteria and cephalosporins (e.g., cefazolin) or vancomycin to destroy Gram-positive bacteria. Treatment may be modified by observation of the patient's clinical course and the laboratory identification of likely microorganisms and their antibiotic sensitivities. Adjunctive patching and early steroid treatment are usually contraindicated.

Topical fluoroquinolone antibiotics (e.g., ciprofloxacin, ofloxacin) were introduced into ophthalmic care in the early 1990s and initiated treatment evolution. Several studies discussed the clinically successful use of 0.3% commercial-strength topical fluoroquinolone antibiotics as monotherapy for suspected bacterial corneal infections without cultures, especially when the lesions were relatively small (<2 mm), and neither central nor deep. Many clinicians found fluoroquinolone monotherapy to be as effective as fortified dual therapy, and initial cultures were believed unnecessary in many cases.

Emerging resistance to the fluoroquinolone antibiotics has been a theoretical concern, however, and recently was reported. Some clinicians are now discussing a new form of dual therapy, utilizing both fluoroquinolone and cephalosporin agents, for example. Treatment of bacterial corneal infection therefore remains an area of some controversy and of evolving strategies, and clinicians are advised to maintain vigilance.

Acanthamoeba Infections

Combinations of the following four types of pharmacological agents have been used successfully for medical treatment of Acanthamoeba keratitis:

• Antibiotic/aminoglycoside: paromomycin, neomycin
• Antifungal: clotrimazole, ketoconazole, itraconazole, miconozole, fluconazole
• Antiparasitic/aromatic diamidine: propamidine isethionate, hydroxystibamidine, hexamidine di-isethionate
• Biocide/cationic antiseptic: polyhexamethylene biguanide, chlorhexidine gluconate, povidone-iodine
• Misdiagnosis and medical failures in the treatment of Acanthamoeba infections are common.

Fungal Infections

Viral Infections

It is prudent to consider discarding contact lenses that have been worn during the period of viral infection and dispense new contact lenses once the infection has resolved. Otherwise, some effort should be made to disinfect contact lenses, perhaps by soaking them in an appropriate disinfecting solution (e.g., contact lens-grade 3% hydrogen peroxide) for 10-15 minutes.

More aggressive medical treatment, including subconjunctival injections and/or systemic antibiotic treatment, hospitalization, and perhaps corneal transplantation, may be necessary, especially in cases of indolent, refractory, or non-bacterial corneal infections. The referral of patients with severe inflammatory or infectious ocular disease to a specialist in corneal and external eye diseases is prudent.

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