In the present study consensus was reached by low vision therapists, clinical physicists and researchers in the field of low vision on a standard protocol for training in the use of CCTVs. The protocol consists of various chapters including several exercises within each chapter. The focus of the training protocol is on ergonomics, basic operation skills, reading, writing, looking at pictures and photographs, and carrying out hobbies. An RCT was conducted to test the effectiveness of the protocol by comparing an intervention group, i.e. patients who receive both instructions provided by the supplier and the new standard training, with a control group, i.e. patients who receive only the instructions from the supplier.
The study will concentrate on predictors of training effects. For example, there might be a 'dose-response' relation between the number of sessions or the time per session and the effect of treatment in terms of primary [15–17] and secondary outcomes. Moreover, we expect that low vision specialists will be able to use our results in deciding which patients will be eligible for training in the future, for example patients with a certain visual acuity or patients who suffer from non-visual co-morbid conditions. Finally, optometrists may have a better indication for referring patients to MRCs for additional training. Moreover, by studying patient files and obtaining data from the participants during the home visits, this study will provide knowledge about the process of counseling and prescribing CCTVs to visually impaired adults (e.g. knowledge about which patients were prescribed a CCTV and about their rehabilitation needs). Consequently, the process of delivering CCTVs will become more transparent. At the time the study was conducted, the exact content of the instructions suppliers provide when they deliver CCTVs to patients' homes was unknown, as well as the time taken for these instructions. We decided not to inform suppliers about the study, to avoid them starting to over perform on their usual instructions, which may vary somewhere between no instructions to basic instructions on how to operate the CCTV. If they would have been informed, a smaller effect of the new standard protocol for CCTV training may be expected. Also, we did not know in advance which supplier would be involved in delivering a CCTV to a particular eligible patient. This depends on the insurance company of the patient and the rehabilitation center that has CCTVs of specific providers on display. In the course of the present study information about these instructions was obtained from participants. Comparability between the treatment and control group with regard to the instructions of the suppliers will be investigated.
There are some limitations to the present study. First, the recruitment of participants by the MRCs took longer than expected. Reasons for this delay were: lack of eligible patients, lack of interest of clients, workload of low vision specialists who were required to invite eligible participants and ethical considerations of a low vision specialist who had conscientious objections to inviting participants with a need for CCTV training. This low vision specialist only invited patients who needed a CCTV, but who could manage without training, so that it would not matter if a patient would be randomized into the control group. Although several actions had been undertaken to convince the low vision specialist of the purpose of the study, and that all eligible patients with a CCTV indication should be invited, it did not work out properly. For this particular MRC, this has caused a selection bias which may lead to an underestimation of the treatment effect which influences generalizability of the results. Therefore, data will be analyzed with and without patients from this specific site.
Second, we only focused on CCTVs with stand mounted cameras and/or displays, since these are the types that are most commonly prescribed in the Netherlands. In addition to stand mounted CCTVs, there are 'mouse' style CCTVs and CCTVs with handheld or head-mounted cameras. All of these devices are more portable than stand mounted CCTVs. However, battery power options tend to be heavy and expensive and, mouse style CCTVs especially, have a limited range of magnification. Head-mounted CCTVs can be used for a wide variety of tasks, nevertheless, patients with macular disease showed better functioning using optical aids compared to head-mounted CCTVs for the majority of tasks in research by Culham et al..
Third, for scientific reasons it would have been preferable to standardize the training protocol further. For instance, to standardize the frequency and the total minutes of training each participant receives, as well as the amount of time practicing with each assignment. However, in daily practice it is very important to amplify care to the characteristics of the individual patient (e.g. learning abilities, endurance and limitations due to co-morbidity). For this reason, training was adjusted to the rehabilitation needs of the participants as well as to their learning style and learning rate, e.g. when participants had major problems with reading, the reading assignments were practiced more intensely. Another advantage of this method is that when the training program has been proven effective, only a few adjustments might be necessary before implementing the protocol in daily practice.
Finally, it would have been preferable to offer placebo-training to the control group, to rule out a Hawthorne effect. An attention deficit in this group may result in a poorer outcome, e.g. a lower experienced quality of life. However, the study of Reeves et al. did not show significant differences in task performance and quality of life between patients who received conventional low vision rehabilitation enhanced by home visits from a rehabilitation officer (who gave advice and demonstrations on the use of LVAs, supplied alternative LVAs and provided patient support) or from a community care worker (who did service as a control for the contact time with patients).