Early detection

As mentioned above, the most important time period is generally between the onset of the disease and its detection by the patient, in par-ticular, when only one eye is affected. How-ever, since ARMD has the potential to pro-gress rapidly, its early detection could considerably reduce the risk of severe, irre-versible vision loss and the costs associated with visual rehabilitation. Some studies tend to show this [Bonastre et al., 2003].

Based on our economic analysis, early screen-ing could reduce the incremental cost-utility ratio from $33,880 per QALY to $22,701 per QALY (patients with classic neovascular ARMD) and from $43,253 to $20,813 (classic and occult neovascular ARMD), which is a substantial decrease. The main reason for this decrease in the cost-utility ratio is that early detection of the disease results in patients re-ceiving a first treatment when they have better initial visual acuity and that, as has been shown, photodynamic therapy is more effec-tive when the patient's visual acuity is good [Bressler, 2001].

It is important to add that our analysis only examines the costs associated with the reha-bilitation and management of patients at cen-tres for semiautonomous or nonautonomous persons but does not include the costs associ-ated with the other symptoms that visual loss leads to. Thus, impaired vision may substan-tially reduce mobility and, as a result, increase the risk of fall-related injuries. Ivers et al.

[1998] found that individuals with neovascu-lar ARMD have a 70% greater risk of falling at least twice in 12 months. As well, visual impairments significantly reduce an individ-ual's ability to perform his/her daily activities, which creates anxiety, emotional distress and depression [Casten et al., 2004; Williams et al., 1998].

Several factors could help promote earlier detection of ARMD in the population. In-creasing patient awareness of the first symp-toms of the disease, encouraging regular

self-examination using a valid test, and better de-tection of ARMD by primary care health pro-fessionals could be some of the basic compo-nents of better detection.

11.5.1 Increasing patient awareness Although no study has specifically examined this subject, most researchers who investigate ARMD and all the comments obtained during the semistructured interviews concur: most adults know little about macular degeneration and do not know that there are effective treatments for it. A survey conducted by Wang et al. [1998] found that one-third of Americans over the age of 50 who present for a periodic ophthalmologic examination that reveals an ophthalmologic problem were not aware that they had an eye disease.

The elderly frequently forget to report their visual loss symptoms to health-care profes-sionals, as they generally attribute them to normal aging or the development of a cataract [Butler et al., 1997a]. According to a number of authors and the experts we met, it is there-fore important to sensitize patients to the first signs and symptoms of macular degeneration so that they can report any visual problem as early as possible and at a stage where the dis-ease can still be treated effectively.

Health professionals (optometrists, general practitioners and ophthalmologists) could therefore play a more important role in dis-seminating information on ARMD. They should ensure that patients report any sudden loss of vision.

11.5.2 Self-examination using the Amsler grid

While many eye diseases are characterized by potentially annoying symptoms that can prompt the patient to seek medical attention, neovascular ARMD is often asymptomatic in its early stages. According to many authors and professional organizations, people can de-tect a macular problem on their own by per-forming a daily self-examination using the Amsler grid, as this test is simple, inexpensive

and quick [Bressler, 2002; Mittra and Singer-man, 2002; Sickenberg, 2001; Butler et al., 1997b].

We therefore performed an exhaustive search of the scientific literature using the keywords grid and Amsler. It identified 110 scientific ar-ticles, including eight on the grid's validity in screening for certain maculopathies (Appen-dix K). However, none of these articles dem-onstrated the validity of this test in the context of early ARMD detection. Consequently, we cannot, for the time being, recommend its use for population ARMD screening.

11.5.3 ARMD detection by primary care health professionals

Given that the first symptoms of visual loss are usually reported to general practitioners and optometrists¹¹ [Mittra and Singerman, 2002], they should be able to correctly iden-tify patients with maculopathy and those at high risk for ARMD. This is apparently not the case at this time. An American study indi-cates that general practitioners have problems correctly diagnosing maculopathies [Mittra and Singerman, 2002]. To ensure better pa-tient routing, measures should be taken to in-crease the training in ophthalmology of gen-eral practitioners. A number of studies found that when primary care physicians were trained to recognize the symptoms of diabetic retinopathy, the rate of detection and referral to ophthalmologists among patients at high risk for visual loss due to this disease was bet-ter [Awh et al., 1991]. Positive results could be obtained if the same were done for the signs and symptoms of age-related macular degeneration [Bressler, 2002].

As for optometrists, it appears that most of them do have the necessary training and in-struments for detecting macular problems [Ordre des optométristes du Québec, 2002].

In October 2003, Québec's National Assembly granted optometrists greater power to

11. This information was obtained during the semistructured interviews as well.

vene therapeutically¹². These measures should increase access to oculovisual health services for all Quebecers by allowing eye specialists and superspecialists to focus on activities that are more in line with their interventional ca-pacity [Ordre des optométristes du Québec, 2002]. However, the potential for earlier maculopathy detection by optometrists sug-gests the possibility of earlier treatment, but to achieve this, there would need to be better co-ordination between optometry and ophthal-mology services, for example, by establishing structured referral paths between optometrists and medical eye specialists.

Furthermore, it might be useful to closely ex-amine the experience of certain Canadian provinces in the field of ocular health care and

12. Prescribing and administering drugs and care for the purposes of treating certain disease states: conjunctivitis, inflammation of the eyelids, corneal disorders and the removal of foreign objects from the surface of the eye.

service organization. The case of Nova Scotia provides an interesting example. In that prov-ince, the optometrist works in close collabora-tion with the family physician, sending him/her all the results of his/her oculovisual examinations. The physician can therefore manage cases more efficiently, since he/she is aware of the entire course of a given visual disease. Furthermore, when a family physician suspects an eye problem in a patient, he/she first refers the patient to an optometrist. The optometrist can eventually refer the patient, if his/her condition so warrants, to the appropri-ate medical eye specialist or treat the patient directly, if the situation so permits [Ordre des optométristes du Québec, 2002; Ordre des op-tométristes du Québec, 2001].

12 CONCLUSION

The chief objective of this report was to assess the efficacy of photodynamic therapy as a treatment for neovascular ARMD and to de-scribe the practice of this treatment in Québec, particularly with regard to the related costs, accessibility and care organization.

We can draw certain conclusions from the in-depth analysis of studies of the efficacy and safety of various treatment modalities for ARMD and from the analysis of the Québec model of the organization of the care pertaining to this disease.