• Child Abuse
• Contact Lenses in the Working Environment
• Colour Vision and Tinted Lenses
• Daytime Running Lights
• Definition of Optometrist
• Disposable Contact Lenses
• Environmental Policy
• Frequency of Examination
• Hepatitis B (BV) Infections
• Highway Visibility
• Human Immunodeficiency Virus (HIV) Infection
• Human Resources
• Hunting
• Impact Resistant Lenses
• Lasers in the Workplace
• Leading Causes of Vision Loss
• Literacy
• Low vision
• Motorists’ Vision and Highway Safety
• Ocular Ultraviolet (UV) Radiation Hazards in Sunlight
• Optometric Preventive Vision Care
• Optometric Terms
• Optometry’s Role in Postoperative Eye Care
• Racquet Sports Eye Protection
• Ready-Made Eyewear
• Refraction as a Stand-Alone Procedure and its Effect on Patient Health
• Refractive Surgery
• Sunglasses
• Supply of Contact Lenses
• Tinted Sports Visors
• Video Display Terminals (VDTs)
• Vision and Learning Disabilities
• Vision and Smoking
• Vision and Eye Health Screening
• Vision Screening of Children
• Visual Therapy

Child Abuse

The Canadian Association of Optometrists (CAO) recognizes that child abuse is a problem affecting a broad spectrum of the population and that there is a need for increased awareness of the physical, psychological, and social harm caused by child abuse. Doctors of Optometry, as primary health care providers, are concerned with the physical, behavioural, and social aspects of children and may recognize evidence of child abuse in the course of an eye examination.

CAO affirms that it is the responsibility of doctors of Optometry, when they recognize evidence of child abuse, to refer and/or report such cases to appropriate authorities consistent with the applicable federal, provincial and local statutes. CAO encourages the Schools of Optometry and other providers of optometric education to include education on child abuse as part of the professional and continuing education programs.

Contact Lenses in the Working Environment

In general, the Canadian Association of Optometrist (CAO) recommends that contact lenses may be worn in the working environment, provided that adequate safety eyewear is utilized. Certain circumstances, however, warrant additional consideration:

1. Any environment where chemicals or fumes may interact with the contact lens material or risk to the eyes. CAO recommends to its members that they query their contact lens patients regarding the environmental conditions under which the lenses will be worn and counsel the patient on those circumstances which may have an adverse effect on the lenses and/or eyes.
2. CAO knows of no circumstances which would prohibit the wearing of contact lenses while wearing a respirator. To date, the wearing of contact lenses while wearing a respirator has been shown to pose no additional hazard to the wearer.
3. Over the past several years, there have been numerous unsubstantiated reports alleging the fusing of contact lenses to the cornea following exposure to a welder’s arc flash. In the Autumn 1990 issue of The Canadian Journal of Optometry / la Revue canadienne d’optomtrie, a Clinical Comment by Dr AP Cullen, Director of the School of Optometry, University of Waterloo concludes that these and similarly described incidents are physically, anatomically and physiologically not possible. CAO therefore endorses the principal findings of Dr Cullen’s analysis of these reports:
   1. A universal ban of contact lenses in the workplace is unwarranted;
   2. Optometrists who prescribe contact lenses for industrial workers should be concerned as to the advisability of wearing lenses in a particular environment;
   3. The practitioner should stress that personal protective equipment is not replaced by contact lenses. Eye protection must be worn;
   4. Contact lenses do not negate the protection afforded by safety equipment; nor do they make the cornea more susceptible to damage by non-ionizing radiation (specifically, arc flashes);
   5. Some contact lenses may give limited added protection in some cases of chemical splash, dust, flying particles and non-ionizing radiation.

Colour Vision and Tinted Lenses

Poor colour vision, or color deficiency, is characterized by the inability to discriminate between colours or shades of colours. There are a number of different factors that can cause this. Most commonly it is due to an inherited genetic disorder for which, unfortunately, there is no treatment. Other possible causes can be diseases of the eye or the visual pathway, certain medications, aging, or chemical toxicity. If the colour deficiency is due to these reasons, treatment may be possible.

Anyone having problems discerning shades of colour should have an eye health examination, including a review of medications and physical health conditions. If the cause of their poor colour vision is determined to be from an inherited disorder, their optometrist can provide counseling about the effects of poor colour discrimination on occupations and daily life. If the poor colour vision is determined to be from medication or disease, an appropriate course of treatment can be undertaken.

The term “colour blind” is outdated and a poor description as it implies lack of any ability to see colour. Monochromatism or lack of any colour perception is quite rare.

Specially tinted lenses, (a coloured filter over eyeglasses or a coloured contact lens on one eye), can improve some people’s ability to differentiate between colours by altering either the brightness contrast or colour contrast so that the colours now appear different. However, the coloured lenses do not increase the shades of colour perceived by an individual, they only help individuals distinguish between certain colours by introducing contrast artifacts. Such lenses cannot make a person with genetic colour deficiency see the colour in a normal manner. Any use of specially tinted lenses to pass a colour test for occupational reasons should have this annotated by their optometrist in the patient file and any reports completed.

Daytime Running Lights

The Canadian Association of Optometrists (CAO) recommends that all vehicles use headlights or daytime running lights while in motion on highways at all times of the day.

Definition of Optometrist

A Doctor of Optometry (optometrist) is an independent primary health care provider who specializes in the examination, diagnosis, treatment, management, and prevention of diseases and disorders of the visual system, the eye and associated structures as well as the diagnosis of the ocular manifestations of systemic conditions.

Disposable Contact Lenses

The concept of disposable contact lenses represents a significant advance in eye care that is justifiably embraced with enthusiasm by practitioners and patients alike. The sophisticated techniques employed in the manufacture of disposable lenses ensures good lens reproduction; minor lens imperfections have been reported but require further investigation to determine their clinical significance.

The regular replacement of contact lenses minimizes the incidence of ocular reactions such as ‘acute red eye’ and deposit accumulation, and enhances comfort and visual performance. The risk of complications such as corneal ulceration can be significantly reduced by wearing disposable lenses on a daily wear basis. Disposable lenses should be replaced as clinically determined by the prescribing optometrist and lens cases should also be regularly replaced. Lenses should be mechanically cleaned and disinfected upon removal. Patients should follow the recommended cleaning and disinfection instructions given to them by their optometrist.

Patients should be advised and counselled by their optometrist on the following:

• the importance of disposing of contact lenses as per the schedule;
• the need to care for and regularly replace the lens case;
• the advisability of the use of contact lenses on a daily-wear basis;
• the proper maintenance protocol for contact lens removed overnight;
• the importance of having regular aftercare examinations;
• the need to be alert for defective lenses;
• the importance of self-examinations with the aid of a mirror (‘feel good, look good, see good [well]‘); and
• the need to seek prompt advice if the above criteria are not met.

Environmental Policy

The Canadian Association of Optometrists (CAO) strives to ensure that, here possible, its office operations conform to the three R’s of environmental protection: Reduce, Reuse and Recycle.

One of Optometry’s primary purposes is the conservation of human vision, and vision is being adversely affected both directly and indirectly by environmental pollution.

CAO expresses its grave concern over environmental pollution of any sort and does hereby pledge its support to all reasonable programs designed to minimize and reduce environmental pollution.

Frequency of Examination

The need for periodic optometric examination has been recognized for many years. Vision and ocular health conditions are not always accompanied by recognizable symptoms. There is often an increase risk to the patient if treatment is not initiated. Relying on the occurrence of obvious symptoms in order to initiate an eye examination exposes the patient to an unnecessary risk.

Many factors will influence the frequency of optometric examinations and only the examining optometrist, upon the analysis of all factors, can determine when a particular patient should return for another examination. However, certain guidelines have been established which can assist the patient in determining the need for examination.

Patients in each age group may be classified as being at low risk or high risk for ocular or vision problems. The minimum frequency of examination for those at low risk is as follows:

• Infants and Toddlers (birth to 24 months) – by age 6 months;
• Preschool (2 to 5 years) – at age 3 and prior to school entry;
• School Age (6 to 19 years) – annually;
• Adult (20 to 64 years) – every one to two years;
• Older Adult (65 years and older) – annually.

The frequency of examination for those at high risk should be determined by the examining optometrist on the basis of the patient’s health, ocular and visual status at the time of examination. Some of the factors which would indicate high risk are as follows:

Infants and Toddlers and Pre-school

Premature birth; low birth weight; mother having rubella; sexually transmitted disease, AIDS related infection; or other medical problems during pregnancy; mother having a history of substance abuse prior to or during pregnancy; family history of high refractive error or eye disease; turned eyes; or congenital eye disorders.

School Age

Children failing to progress educationally; children exhibiting reading and/or learning disabilities.

Adult

Diabetes; hypertension; family history of glaucoma; those who work in visually demanding or eye hazardous conditions.

Older Adult

Diabetes; hypertension; family history of glaucoma; those taking systemic medication with ocular side effects.

Hepatitis B (BV) Infections

The Canadian Association of Optometrists (CAO) recognizes that infections resulting from the hepatitis B virus (HBV) is a serious health issue. Doctors of Optometry may, in the course of an eye examination, encounter carriers of HBV and must be knowledgeable in and actively practice universal precautions which will reduce the risk of transmission.

CAO strongly recommends that it be the responsibility of doctors of Optometry, to acquire a sound understanding of the specific and unique etiology and pathology of HBV infections, appropriate infection control, and related public health and patient care issues. CAO encourages the Schools of Optometry and other providers of optometric education to include education on HBV as part of the professional and continuing education programs.

Highway Visibility

Studies have shown that drivers find it difficult to see typically clothed pedestrians during twilight and night time. This is a contributing factor in the rising number of deaths and injuries of pedestrians and cyclists under poor lighting conditions. It has been demonstrated that the use of reflective materials makes individuals and other objects more readily visible to drivers.

The Canadian Association of Optometrists (CAO) recommends the use of reflective materials on clothing and other accoutrements by pedestrians and cyclists utilizing the roadway during twilight or night time.

Human Immunodeficiency Virus (HIV) Infection

Patients with Acquired Immune Deficiency Syndrome (AIDS) and AIDS-Related Complex (ARC) are subject to serious ocular complications. The Canadian Association of Optometrists (CAO) strongly recommends that patients with AIDS or ARC should seek appropriate eye care from an optometrist.

CAO strongly recommends that it be the responsibility of all practising optometrists to acquire background and knowledge, through continuing education, of Human Immunodeficiency Virus infections, of appropriate infection control and of related public health and patient care issues. CAO encourages the Schools of Optometry and other providers of optometric education to include education on HIV as part of the professional and continuing education programs.

Human Resources

It is the position of the Canadian Association of Optometrists that optometry is the profession best positioned to serve the primary eye care needs of the public. In light of projected increases in demand for these services, CAO supports initiatives, which ensure appropriate optometric human resource needs, are met now and in the future.

Hunting

The Canadian Association of Optometrists (CAO) recommends that hunters and those accompanying them wear fluorescent blaze orange (with a dominant wavelength between 595 and 605 nanometres, a luminance factor of not less than 50% and an excitation purity of not less than 90%) at all times when in hunting areas.

Impact Resistant Lenses

The Canadian Association of Optometrists (CAO) supports in principle the prescribing of impact resistant lenses in all cases except those where such lenses will not fulfil the visual requirements of the particular patient. Recent studies have shown that photochromic glass lenses do not meet the Canadian Standards Association (CSA) Z94 3-M88 standard and therefore should not be used in industrial lenses. Furthermore, CSA has determined that glass lenses of all types do not meet the minimum standards for impact resistance. CAO recommends that impact resistant lenses dispensed by optometrists should comply with the CSA Z94.3-M88 standard.

Lasers in the Workplace

The Canadian Association of Optometrists (CAO) endorses the ANSI Z136.1 1986 (American National Standards Institute) standard for the safe use of lasers.

Leading Causes of Vision Loss

Diabetic eye disease, glaucoma and macular degeneration are among the leading causes of vision loss in Canada. Early detection and diagnosis with timely and appropriate treatment may significantly reduce the risk of visual impairment and blindness.

Therefore, patients known to have, or to be at risk for development of these conditions, should promptly receive an initial comprehensive eye examination including ophthalmoscopic examination through dilated pupils (unless dilation is contraindicated).

The Canadian Association of Optometrists (CAO) recommends that patients with diabetes, glaucoma or macular degeneration after having obtained an initial examination, should receive annual eye examination unless more frequent evaluations are indicated. In the case of diabetics, CAO recommends that a comprehensive dilated eye and visual examination should be performed annually for all patients who a) are 12 years old or older and who have had the disease for 5 years, b) are over the age of 30 regardless of how long they have had the disease and c) have visual symptoms and/or abnormalities.

Literacy

It is estimated that one billion adults in the world, including many in Canada, may suffer from poor literacy skills. The Canadian Association of Optometrists (CAO) recognizes that, while the causes of reading difficulties are many, a vision problem is one cause that is often overlooked. In many cases, undetected visual dysfunction interferes with an individual’s learning and reading ability. Since reading difficulties may have multiple causes, treatment must be interdisciplinary involving the efforts of optometrists, educators, psychologists and other professionals. All efforts must be designed to help people take control of their lives and contribute to the development of their communities.

Therefore, CAO supports activities designed to educate the public on vision’s role in the learning process and in the workplace, as well as on the importance of early detection and vision development guidance through comprehensive optometric evaluations.

Low Vision

Low Vision refers to a condition of diminished visual capability which cannot be improved by surgical or medical therapy, or by routine methods, such as spectacles or contact lenses, to a sufficient level that would enable an individual to perform common visual tasks adequately.

Functional blindness describes a condition of severely limited visual capability (cannot be improved by surgical, medical, refractive or sight enhancement aids) which severely reduces the ability of the person to function normally in daily tasks.

Legal blindness is strictly a statutory but arbitrary definition of a minimal level of vision, generally considered to be 6/60 (20/200) acuity and/or 20 degrees of visual field.

It is the policy of the Canadian Association of Optometrists (CAO) with respect to low vision:

1. to advance the well-being of visually impaired Canadians and to promote their universal access to high quality low vision care;
2. to promote high quality basic and applied low vision research;
3. to encourage the legitimate role of Optometry as a key provider of clinical low vision services within a comprehensive interdisciplinary low vision service;
4. to co-operate constructively with other agencies, organizations or professions who share CAO’s desire to help Canadians with low vision;
5. to help visually impaired Canadians cope with their ever-increasing technological environment by providing directly, or by referring when appropriate, exposure to advanced low vision technology;
6. to participate actively in the delivery of quality low vision services to the multiply-handicapped;
7. to promote a better understanding of low vision by educators, employers, legislators, agencies for the blind and the general public;
8. to encourage appropriate health care measures leading to the earliest possible detection, diagnosis and treatment of sight threatening diseases or injuries, and;
9. to better inform health care practitioners concerning the pressing need for early referral for professional low vision services as an integral part of their management of patients with ocular disorders.

Motorist’s Vision and Highway Safety

The Canadian Association of Optometrists (CAO) and individual corporate members should regularly offer their co-operation to provincial motor vehicle licensing boards and make available to them such publications and expertise as is available on vision and driving safety, in order to assist in the prevention of injuries and loss of life in motor vehicle accidents.

Ocular Ultraviolet (UV) Radiation Hazards in Sunlight

The Canadian Association of Optometrists (CAO) recognizes that exposure to ultraviolet (UV) radiation (and in particular, those portions known as UV-A and UV-B) is a contributing factor in producing ocular diseases such as age-related cataract, pterygium, cancers of the skin around the eye, photokeratitis, and corneal degenerative changes and may contribute to macular degeneration.

CAO recommends that optometrists educate their patients in the risks of UV exposure to the eye and other tissues and that they advise their patients on the appropriate means to provide protection from solar UV radiation.

CAO recommends that optometrists encourage the use of eyewear, including prescription and non-prescription spectacles, contact lenses, and intra-ocular lens implants, which absorb 99 to 100% of the entire UV-A and UV-B spectrum up to 400 nm.

Optometric Preventive Vision Care

Optometric preventive vision care involves all phases of the practice of Optometry. It is the arranging of conditions and situations in order to allow the individual to function at his or her highest level of visual performance and may be provided at three levels.

Primary optometric preventive vision care means setting the stage to prevent the onset of visual conditions so that they will not be detrimental to the full development of the individual’s potential, and that visual performance can be raised and enhanced to optimum levels.

Secondary optometric preventive vision care means preventing or reversing ongoing vision deterioration, so that any interference with the individual’s potential would be reversed, and visual performance can be raised above minimum levels.

Tertiary optometric preventive vision care means preventing an existing vision condition from further deterioration, to alleviate the seriousness of the disability and dependence resulting from reduced potential so minimum levels of visual performance are maintained.

Optometric Terms

The Canadian Association of Optometrists (CAO) encourages the use of current and proper optometric terminology in optometric correspondence and literature.

Optometry’s Role in Postoperative Eye Care

Doctors of Optometry are legally qualified, educationally trained, and clinically competent to provide post-operative care. Doctors of Optometry have been providing quality post-operative care on a cost-effective basis in consultation and co-management with ophthalmologists for many years. Judgements on the delivery of post-operative care shall be made in consultation with the patient’s optometrist. In accordance with such judgements, the post-operative care and patient co-management shall be rendered by the operating surgeon and the Doctor of Optometry.

Racquet Sports Eye Protection

The risk of eye injuries that can be suffered by participants in racquet sports has been well established. The Canadian Association of Optometrists (CAO) recommends that all participants in racquet sports wear appropriate eye protection while engaging in the sport. Furthermore, CAO recommends that all organizations which promote these sports or which provide facilities for these sports, encourage all participants to wear appropriate eye protection.

CAO endorses the use of the Canadian Standards Association’s Preliminary Standard P400-M1 9B2 Racquet Sports Eye Protection and considers that all eye protectors for racquet sports (CSA Class Number 7264 01) which meet this standard to be appropriate eye protection as referred to above.

Ready Made Eyewear

Ready-made eyewear for the relief of simple myopia, hyperopia or presbyopia is displayed, marketed and sold in non-optical commercial environments. The consumer self selects the device. Such devices are manufactured en masse without reference to a specific wearer’s prescription needs. Ready made devices that correct astigmatism or unequal prescriptions are not available.

Although it is possible for an individual with simple myopia, hyperopia, or presbyopia equal in both eyes with no astigmatism to select an adequate visual device by self-selection, the majority of persons will not achieve proper correction because of the prevalence of astigmatism and unequal refractive errors in the population as a whole. Self-selection is a trial-and-error process. Both the prevalence of more complicated refractive errors and the limited number of devices usually available result in what is often an inadequate or unsafe visual correction.

Furthermore, ready-made eyewear may give the wearer an illusion of comfort and relief of the vision problem without actually resolving the problem. Self-diagnosis of vision problems may delay the diagnosis, treatment and management of eye disease or other health problems.

For these reasons, the Canadian Association of Optometrists (CAO) does not approve of the availability of ready-made eyewear.

Where ready-made eyewear is permissible under law, CAO advises the following:

1. regular eye examinations for people of all ages. Upon examination, the optometrist will recommend an appropriate visual device and the advisability of using ready-made eyewear should never substitute for a regular eye examination;
2. ready-made eyewear devices may not properly correct vision and may mask certain serious eye conditions. Have your eyes professionally examined before using these devices;
3. ready-made eyewear should be manufactured to resist accidental lens breakage in accordance with ANSI standards established for non-industrial eyeglass lenses.

Refraction as a Stand-alone Procedure and Its Effect on Patient Health

The Canadian Association of Optometrists (CAO) is concerned about protecting the visual welfare of the public by promoting high standard of patient care. CAO recognizes that an eye health and vision examination is an essential element in the diagnosis of eye disease and many health problems, including some life-threatening diseases. Early diagnosis of many conditions can prevent irreparable harm. A refraction for the purpose of determining the need for corrective lenses is part of a series of interconnecting procedures which make up an eye health and vision examination.

CAO, further, encourages its corporate members to oppose any effort to permit refractions to be performed independent of an eye examination unless the professional judgement of the optometrist or ophthalmologist indicates otherwise.

Refractive Surgery

The Canadian Association of Optometrist (CAO) recognizes all forms of refractive surgery to be evolving techniques for the reduction of ametropia. CAO recommends that candidates for this type of surgery be fully informed of all aspects of the procedures. CAO also supports the role of the optometrist in managing the refractive surgery patient before, during and after the procedure.

Sunglasses

The use of both non-prescription and prescription sunglasses has increased dramatically in the past few years. As a rule of thumb, the greater the exposure to sunlight, the greater the need for appropriate protection. Not everyone needs maximum protection, but at certain times or in certain occupations, this is recommended.

Most healthy individuals can compensate for bright light conditions through normal changes in their state of light/ dark adaptation. Changing lifestyles and the cosmetic appeal of sunglasses have resulted in more people wearing sunglasses to take advantage of the increased visual comfort which they can provide. However, sunglasses should provide much more than cosmetically appealing protection from bright light.

It is particularly important that sunglasses protect the eye from ultraviolet radiation. Ultraviolet radiation (UV) is not visible to the human eye but may cause damage to it. Vision research provides conclusive evidence of a direct link between exposure to UV and the development of certain types of cataracts. UV light can also lead to the development of, and accelerate the progression of, macular degeneration. Many sunglasses may not provide protection to UV radiation. This may lead to damage of the eye and ocular adnexa if the wearer incorrectly assumes that the lenses provide UV protection. Sunglass lenses should therefore be made of materials, which not only reduce the amount of visible light entering the eye but also absorb all UV radiation present under any conditions found in daily living.

If the optical quality is poor, visual distortion may result which could, in turn, hamper visual performance. Consideration should also be given to such factors as frame quality and the impact resistance of the lenses. The selection of a particular tint may vary depending upon personal tastes but it is important to be aware that some tints significantly affect colour perception.

CAO advises that those who choose to wear sunglasses should ensure that they are of good quality with optical properties similar to those of prescription lenses. Individuals should obtain professional advice to ensure that the optimum design and type of sunglass lenses are chosen to provide maximum visual efficiency, comfort and ultraviolet protection.

Supply of Contact Lenses

The Canadian Association of Optometrists (CAO) recognizes that the delivery of contact lenses is presently being promoted by a number of non-traditional methods including direct mail or WATS line. Such methods do not allow for the visual inspection of the contact lenses prior to delivery, nor do they allow for an evaluation of the physiological adaptation of the eye by a qualified practitioner. This situation poses a potential and unnecessary risk to the contact lens wearer.

CAO, therefore, endorses and encourages the delivery of a contact lens to a patient only by a licensed practitioner who shall take full responsibility for ensuring the safety and efficacy of the lens on the eye, including appropriate follow-up care as indicated. Where the licensed practitioner contracts with a contact lens company to provide delivery directly to the patient, it is the practitioner who shall initiate the order for the contact lenses after consultation with the patient and/or patient record. The practitioner shall authorize shipments of contact lenses only to those patients a) who have maintained their schedule of follow-up examinations, b) whose contact lens prescriptions have not expired, and c) who have given consent for their name and home or work address to be given to a third party. It is improper for the contact lens supplier to provide contact lenses to the patient on an automatic basis or by direct contact with the patient. The practitioner shall also ensure that patient confidentiality is preserved and that the contact lens supplier does not communicate with the patient for any purpose other than for the delivery of the contact lenses.

Tinted Sports Visors

The Canadian Association of Optometrists recommends that Tinted Sports Visors not be allowed under any circumstances. A player with potential neck & head injury requires an evaluation of their pupil reflexes to determine the extent of any neurological injury. Such a player would also need to have cervical spine immobilization for precautionary reasons. To properly evaluate the pupils, medical personnel would need to remove the tinted visor to allow access to the player’s pupils. The process of removing the visor poses too great a risk to further injuring the player’s cervical spine or brain.

Clear visors that allow the pupils to be evaluated and that are properly designed for eye protection pose no such problem and are encouraged.

If a player needed or wanted a tinted eye shield, this could be best achieved by tinted eyeglasses or contact lenses, which could be easily removed to allow access to the pupils without risk of moving the player’s head or neck.

Video Display Terminals

The Canadian Association of Optometrists (CAO) recognizes the potential for visual stress in the use of Video Display Terminals (VDTs). This stress may be caused by poor lighting conditions, improper ergonomic work stations, excessive concentration at the near point, and uncorrected refractive or oculomotor anomalies. CAO recommends that a VDT user consult with his/her optometrist with regard to these problems. Furthermore, CAO recommends that an individual who uses a VDT should ensure that, for each 55 minutes of VDT use, five minutes be spent with the eyes closed and at rest, or in the performance of tasks which do not require close work.

CAO acknowledges that current research does not indicate that there is any evidence of physiological effects due to the radiation produced by VDTs. CAO recommends that regular eye examinations of a VDT user be performed for the purpose of early detection and remedy of any visual problems.

Vision and Learning Disabilities

The relationship between school performance and various aspects of vision, including fixation and eye movement abilities, accommodation, convergence, binocularity, eye-hand co-ordination, and visual form perception has been studied extensively. In general, neither myopia nor distance acuity appear to be associated with learning difficulties. However, conditions which require greater effort at a near point have been associated with reduced reading ability.

Problems in these dynamic aspects of vision can result in headaches, mental fatigue, blurred or double vision, loss of fixation, or reduced ability to concentrate on close tasks. Deficient eye co-ordination causes an increase in the errors made in reading and writing. Learning disability or dyslexia often demonstrates some or all of these symptoms. Optometrists treat visual dysfunctions which may present an obstacle to learning. Children with learning disabilities constitute a group which is particularly at risk from further obstacles.

The Canadian Association of Optometrist (CAO) is well aware that some empiricists view dyslexia as a brain disorder while developmentalists view it as an environmental and learning disorder. In viewing various segments of the population, both are probably correct. Optometry feels that since a learning disability is undoubtedly the result of a multiplicity of causative factors, its amelioration is best affected by a multidisciplinary approach. Certainly, some aspects of a learning disability arise in the areas of vision and visual perception and such aspects can quite properly be cared for by optometrist. However, interprofessional and jurisdictional disputes should be forgotten and all the disciplines involved in searching out a solution to this problem should share their skills, knowledge, theories, and clinical methods so that the learning disabled child will benefit from the improvements which must evolve from such an eclectic approach.

CAO recognizes that a correlation has been established between visual problems and reading disabilities. Optometry does not claim the ability to treat or cure specific learning disabilities or dyslexia, but CAO contends it is reasonable to provide learning disabled patients with optometric assistance if they exhibit the signs and symptoms of a visual anomaly which is treatable. For this reason, CAO recommends that children who are suspected of suffering a learning disability should have a thorough eye examination.

Vision and Smoking

The Canadian Association of Optometrists (CAO) recognizes that the inhalation of tobacco smoke by smokers and non-smokers contributes several harmful and potentially dangerous effects on vision. Specific effects are:

1. A smoking mother’s effect on her unborn child

   Scientific study has demonstrated that babies whose mothers smoked while pregnant had a significantly greater number of eye defects and vision problems than that suffered by babies born to non-smoking mothers.

2. Reduced night vision

   Nicotine can cause the constriction of some blood vessels in the eye and thus reduce the supply of oxygen to ocular tissues. Carbon monoxide reduces the ability of the blood to combine with and carry oxygen. The combined effects of these chemicals will interfere with the eye’s ability to adapt quickly to the changing conditions of light and dark often encountered when driving at night. The time required to regain adequate night vision after exposure to a bright light is substantially longer for a smoker than for a non-smoker.

3. Eye irritation

   The most consistently cited complaint with respect to the effects of smoking is eye irritation. Irritation of the eye is due to smoke particles and other airborne residues of burning tobacco.

4. Reduced in the size of the visual field

   Studies have shown that smokers generally have a narrower field of vision than non-smokers. The reduced flow of oxygen to the blood vessels in the eyes will have its greatest effect on the retinal cells which provide peripheral vision. Persons who depend on their peripheral vision, such as drivers and athletes, risk impairment of this ability if they smoke.

5. Blindness

   Studies have shown that a link exists between cerebral arteriosclerosis (a condition that often leads to strokes) and cigarette smoking. In addition to paralysis, strokes can also result in permanent blindness.

6. Tobacco amblyopia

   Tobacco amblyopia is a condition characterized by a loss of visual sharpness and reduced ability to perceive colour. It is often due to a combination of smoking, alcohol abuse and a generally poor diet.

   With due consideration to the foregoing effects, CAO therefore encourages the elimination of smoking in areas of public access and endorses programs which discourage smoking habits. Furthermore, CAO supports disseminating information regarding the harmful effects of smoking on vision.

   CAO also encourages optometrists to declare those areas of their offices accessible to the public to be smoke-free environments. Finally, CAO also supports the elimination of advertising designed to promote the use of tobacco products.

7. Increased risk for the development of the Macular Degeneration

   Tobacco smoking has been shown to be a positive factor for the development of macular degeneration. Macular degeneration is the leading cause of new blindness in adults over the age of 65.

8. Increased risk for the development of Cataract

   Tobacco smoking has been shown to lead to development of cataracts. Cataracts tend to develop at an earlier age in smokers.

Vision and Eye Health Screening

The purpose of a screening program is to detect the possible presence of a vision or health related condition and to make the appropriate referral for further investigation.

The screening should maintain a high specificity (test positive if disease present) and high sensitivity (confirm those to be disease free).

Any vision screening program should ensure that:

1. it is performed by qualified and trained individuals;
2. appropriate equipment is used;
3. an appropriate setting is used;
4. there is a reasonable expectation of valid and reliable results.

Individuals being screened should be properly informed of the limitations of the screening and it should be clearly communicated that a vision screening does not replace a comprehensive eye examination or routine eye care.

All efforts must be made to ensure that patient information and results obtained are kept in strict confidence.

Vision Screening of Children

Any undetected vision problem may result in the reduction of the efficiency of the visual system. This may further result in the inability of children to achieve their full potential.

The Canadian Association of Optometrists (CAO) supports the position that Optometry should be a part of a multi-disciplinary effort that examines, diagnoses and treats the infant’s visual system during the first five years of life.

CAO encourages the implementation of effective vision screening programs for young children. The earlier in life such programs can be applied the greater the potential benefit to the child. Irrespective of the performance of vision screening programs, CAO recommends that all children should have a completed professional eye examination before the age of three.

CAO also supports the position that all children receive a comprehensive eye/vision examination assessing and treating any deficiencies in ocular health, visual acuity, refractive status, oculo-motility, and binocular vision prior to entering school. This mandatory examination should be followed by periodic eye/vision examination in addition to vision screening programs that are well-designed and properly administered in public or private schools to identify children in need of further care.

Visual Therapy

Vision is the process of deriving meaning from what is seen. It involves more than simply visual acuity (the ability to distinguish fine details). This aspect is normally influenced by the refractive state of the eye (i.e. the presence of near-sightedness, farsightedness, astigmatism, and presbyopia). It also involves the ability to fixate on an object, to focus on an object, and to co-ordinate eye movements, as well as eye-hand co-ordination and visual form perception.

Vision continues to develop after birth and is influenced by the visual environment and the individual’s experience. Improper development may result in inefficient or uncomfortable vision. Good visual acuity and healthy eyes are no assurance that an individual does not have a vision problem.

Optometric vision therapy (also called orthoptics or vision training) is a treatment plan used to correct or improve specific dysfunctions of the vision system. It includes, but is not limited to, the treatment of strabismus, other binocular abnormalities, ocular motor dysfunctions, and visual-perceptual-motor disabilities.

Optometric vision therapy is based upon a medically necessary plan of treatment which is designed to improve specific vision dysfunctions determined by standardized diagnostic criteria. Treatment plans encompass lenses, prisms, occlusion and the use of other appropriate materials, modalities and equipment.

Each program of visual therapy must be designed to suit the specific needs of the patient. The frequency of consultation, the amount of home or office training and the duration of program will vary dependent upon the nature and severity of the problem.

The Canadian Association of Optometrists (CAO) affirms its position that vision therapy is an effective modality in the treatment of physiological dysfunctions of the vision system. Optometric vision therapy provides individuals with the opportunity to develop visual abilities and efficiency most suited to their visual needs and enables those individuals to achieve maximal levels of performance.