Successful outcomes from a structured curriculum used in the veterans affairs low vision intervention trial.

Abstract: A low vision rehabilitation program with a structured curriculum was evaluated in a randomized controlled trial. The treatment group demonstrated large improvements in self-reported visual function (reading, mobility, visual information processing, visual motor skills, and overall). The team approach and the protocols of the treatment program are described.

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Outcomes research is focused on understanding the "end results" of health care interventions (Agency for Healthcare Research and Quality, 2000). For individuals with chronic conditions, for whom a cure is not possible, "end results" must include measures of effects that they experience and care about, such as their perception of their ability to function at home and in the community. "For clinicians and patients, outcomes research informs decision making by providing evidence of the risks, benefits, and results of treatment" (Agency for Healthcare Research and Quality, 2000). Clinicians who use evidence-based practice integrate their clinical experience with research evidence in making decisions about the care of individual patients (Mozlin, 2000). As health care costs escalate and increase competition for resources, policy makers are using outcomes research to identify strategies that can be implemented through evidence-based policy to improve the "quality and value of care" (Gray, 2001).

The need, demand, and costs associated with low vision care are expected to increase as the U.S. population ages because there is as yet no cure for most age-related eye diseases, and the incidence and prevalence rates of chronic visual impairments increase rapidly with age (Massof, 2002). Low vision outcomes must be studied, using the same standards that are applied to other medical treatments, with scientifically rigorous studies, such as randomized controlled trials, to develop an evidence base to guide policy and funding decisions and support guidelines for clinical practice.

The Department of Veterans Affairs (VA) Low Vision Intervention Trial (LOVIT) was designed to provide evidence of the effectiveness of low vision rehabilitation. LOVIT evaluated an outpatient-based low vision rehabilitation program that was targeted to veterans with moderate and severe macular diseases using a randomized controlled trial design. The program was modeled after the inpatient Hines Blind Rehabilitation Center low vision rehabilitation program, that has been shown to be effective in previous outcomes studies (Stelmack, Moran, Dean, & Massof, 2007; Stelmack, Stelmack, & Massof, 2002; Stelmack et al., 2006) using lessons that were adopted from or are similar to those found in manuals and textbooks on low vision therapy (Backman & Inde, 1979; Freeman & Jose, 2000; Jose, 1985; Lund & Watson, 1997; Quillman, 1980; Wright & Watson, 1995). The goal of the LOVIT investigators was to determine if the low vision program achieved at least a moderate treatment effect. If so, the program could be compared to other service delivery models or curricula in future studies.

LOVIT was conducted at the Hines, Illinois, and Salisbury, North Carolina, VA medical facilities. The institutional review boards at both facilities approved the protocol and informed consents. The research followed the tenets of the Declaration of Helsinki for research on human subjects. The participants in the trial were 126 veterans with macular diseases whose visual acuity in the better-seeing eye was worse than 20/100 and better than 20/500. They were selected randomly for low vision rehabilitation treatment (a low vision examination followed by six weekly therapy sessions and the prescription and dispensing of low vision devices) or were placed on a waiting list control group. Those in the control group were offered other low vision services or admission to a VA blind rehabilitation center after the trial was completed.

The participants in the treatment and control groups rated the difficulty they experienced performing common activities during the telephone administration of the VA Low Vision Visual Functioning Questionnaire-48 (VA LV VFQ-48) (Stelmack, Szlyk, Stelmack, Babcock-Parziale et al., 2004; Stelmack, Szlyk, Stelmack, Demers-Turco et al., 2004, 2006; Szlyk et al., 2004) at the baseline and four months after the baseline. Visual ability--the ability to perform activities altered by visual impairment--was calculated from the difficulty ratings on the VA LV VFQ-48. The primary outcome measure for the trial was a comparison of changes in the scores on visual reading ability in the treatment and control groups. Secondary outcomes were comparisons of changes in other visual ability domains (mobility, visual information processing, and visual motor skills) and overall visual ability in the treatment and control groups.

The LOVIT treatment group demonstrated significant improvement in all aspects of self-reported visual function compared to the control group, which experienced a decrease in visual ability during the four-month wait for low vision or blind rehabilitation services. Effect sizes (differences in the mean change scores divided by the pooled standard deviation of the changes) for the treatment group compared to the control group (Cohen, 1988) were 2.51 for reading ability, 1.14 for mobility, 2.03 for visual information processing, 1.82 for visual motor skills, and 2.51 for overall visual function; p < .001 for all analyses (Stelmack et al., 2008). Treatment effects were defined by Cohen (1988) as small (0.2), medium, (0.5), and large (over 0.8).

On the basis of the large treatment effects that were observed for many functional domains (reading, mobility, visual information processing, visual motor skills, and overall visual function), we concluded that at least 10 hours of low vision therapy, including a home visit, was justified for patients with moderate and severe visual impairments. Structured homework assignments that the instructor would review with the patients were also recommended. The decline in visual function experienced by the control group supports our recommendation that low vision rehabilitation should be offered as soon as possible following a diagnosis of AMD.

This article presents a detailed description of the low vision rehabilitation program provided for veterans who were randomly placed in the treatment group. Additional details can be obtained from the LOVIT protocols for the low vision examination, and instruction, and homework exercises can be downloaded from the Johns Hopkins Low Vision Consensus Project web site, <www.lowvisionproject.org>, or the VA Optometry web site, <www. va.gov/optometry>. The reader is also referred to previous publications for more detailed descriptions and discussion of the study design, methods, and outcomes of the trial (Stelmack, Tang et al., 2007, 2008).

Methods

DEVELOPMENT OF THE LOW VISION REHABILITATION PROGRAM

Because of the success measured at the low vision program of the Hines Blind Rehabilitation Center (Stelmack et al., 2002; Stelmack, Tang et al., 2006, 2007), original lesson plans from that program were evaluated by the project team to determine their appropriateness in the design. The lessons were shortened, strengthened, and formalized to accommodate an outpatient-based program with fewer therapy hours. Homework was substituted for practice supervised by therapists during the classes. A home visit was added to reinforce environmental modifications and techniques; to set up visual devices, such as closed-circuit televisions (CCTVs); and to adjust teleloupes, so the patients could practice at home with these devices. The plan provided six therapy sessions (usually a week apart).

Low vision devices (refractive correction when necessary; a desktop CCTV; a monocular telescope; teleloupes; a pocket magnifier; a stand magnifier; reading glasses; a reading stand; lamps for controlling illumination; and filters to control glare, such as sunglasses with infrared and ultraviolet protection) were prescribed when appropriate and dispensed to the LOVIT participants at no charge according to VA policy (Veterans Health Administration, 2005).

The service delivery system used for LOVIT included an optometrist and a certified low vision therapist who worked together as a team following professional guidelines (Academy for Certification of Vision Rehabilitation and Education Professionals, 2000; American Optometric Association, 1997). The optometrist and low vision therapist conducted the low vision examination, which included the patient's history (medical, visual, and social); discussion of specific goals and needs; and clinical assessments of distance and near visual acuity, MNREAD Acuity Chart, eccentric viewing, contrast sensitivity, binocular vision and ocular motility, ocular health, and visual field. The optometrist's examination also included refraction and an evaluation of low vision devices. Counseling on the eye disease and visual impairment was provided. After the examination, therapy to manage the visual impairment and recommended low vision devices were incorporated into a rehabilitation plan. The low vision rehabilitation team reviewed the rehabilitation plan and therapy program with the veteran. A member of the veteran's family or a significant other was invited to participate if the veteran consented. The low vision rehabilitation team met frequently to discuss the veteran's progress and to finalize prescriptions at the conclusion of the therapy program.

THERAPY AND HOMEWORK PROTOCOLS

Patients with low vision typically express a common goal of wanting to "see better at all distances." Refraction, followed by the prescription of new daily-wear lenses, eccentric viewing, or medical or surgical intervention, may improve their visual acuity. Low vision strategies and devices are used to enhance the patients' remaining vision and to improve their visual efficiency. Our therapy plan began with the development of eccentric viewing skills using the recommended spectacle prescription for best visual acuity and then emphasized a series of more specific objectives that basically encompassed the universal goal of "seeing better":

Viewing things at a near distance. This objective included the following:

1. Spot reading at near distance (such as reading price tags, menus, return addresses on envelopes, labels on medicine bottles, and thermostats). A pocket magnifier was usually prescribed for this task.

2. Short-duration or portable reading (like recipes or product instructions at home and a hymnal or study-group materials away from home). A stand magnifier or reading glasses were usually prescribed for this task, although a pocket magnifier could also be used.

3. Sustained reading of continuous text materials (for example, newspapers, magazines, correspondence, or religious materials). A CCTV, along with eyeglasses to focus on the screen, was usually prescribed for this task, although reading glasses or a stand magnifier could also be used.

4. Writing. Tasks like maintaining a checkbook or financial records, paying bills, filling out forms, doing crossword puzzles, or writing letters were usually taught using a CCTV. Tasks like writing down telephone numbers, writing notes, labeling, and creating a readable list of commonly called telephone numbers were often addressed by instruction in writing with a felt-tipped pen. Tasks like signing a check or important papers away from home were usually met by instruction in the use of a signature guide.

Far and intermediate distance viewing. This objective included the following:

1. Spot reading or viewing at far and intermediate distances (such as reading street signs, menus behind counters, and grocery aisle markers; seeing things of interest like scenery while traveling, wildlife, faces, holiday displays, golf greens, bowling pins, and the like. A monocular telescope was usually prescribed for these activities.

2. Sustained long-distance viewing (such as watching television programs, public performances, sporting events, or wildlife). Teleloupes were usually prescribed for these activities.

Seeing things in the home (environmental modification). The objectives included (1) placing a CCTV for efficiency and ideal viewing; (2) improving lighting and window treatments to reduce unwanted glare; (3) providing instruction in using visual and tactile labels to mark dials, buttons, and other controls; and (4) teaching the functional uses of brightness and color contrast and ways of manipulating the size of the retinal image and reducing visual clutter to facilitate visual function.

The use of devices or skills that emphasized the specified goals just described was taught at each lesson. Nonoptical devices and ancillary skills were taught in conjunction with optical devices that reinforced the development of skills.

Each participant was given a homework package that included all necessary materials. Homework was assigned at each lesson and reviewed at the next. The assignments were intended to enhance the participants' efficiency and confidence, to encourage practice that was designed to decrease the number and duration of therapy sessions that were needed to complete a rehabilitation program, to improve the carryover of skills by having the participants practice everyday tasks at home, to provide opportunities for independent decision making and problem solving, to demonstrate a large variety of potential uses for a particular low vision device, and to identify problems and develop competence so that the device or technique would not be burdensome to use. The decision to include homework that could be easily scored was made on the basis of our clinical experience that general recommendations, such as "practice with this device," often do not result in sufficient practice time to reinforce the skills that are taught. Having homework returned to the low vision therapist and discussing the homework as it was being graded enabled the low vision therapist to evaluate the participants' development of skills to determine if a review or additional therapy was needed.

Instructional components of eccentric viewing

Throughout therapy, a strong eccentric viewing program was emphasized to improve eye control and the management of scotomas and to optimize the participants' performance with the visual devices that were later introduced. The introductory strategies that were taught to the participants to improve eccentric viewing are described in Box 1.

Homework was designed to provide practice sessions for the specific skills that were taught at each session. Initially, the homework lessons were provided to practice eccentric viewing without magnification, such as finding and circling specific letters within word lists or sentences and exercises using playing cards. Later, homework incorporated eccentric viewing with magnification devices. Initial homework materials included materials in a variety of print sizes, depending on each participant's visual acuity. Later, the print size was reduced to regular print when eccentric viewing and the use of devices were more developed. The participants were also encouraged to practice eccentric viewing to read a standard deck of playing cards and were told to hold the cards far enough away to make the exercises challenging. Practice included three exercises: (1) locating the eccentric viewing position: viewing individual cards and using the eccentric viewing position to read the card index; (2) fixating with eccentric viewing: stabilizing the eccentric viewing position on the top, left-hand corner of a deck of cards and quickly removing one card at a time while trying to maintain the eccentric viewing position; and (3) scanning with eccentric viewing: fanning approximately seven playing cards and practicing reading the card indices quickly and accurately.

Box 1

Instructional Components
of Eccentric Viewing and
Management of Scotomas

* Educate the patient through
discussion and demonstration that
"straight ahead" or central vision
now has a blind spot or scotoma
and is no longer the best vision.

* Explain that eccentric viewing will
teach the patient a new way to
"look" at things that will improve
visual function.

* Instruct the patient to look at an
object about 5-10 feet directly
ahead, imagine a clock face around
that object, and move the eye toward
a specified clock number to see the
object better.

* Provide multiple practice experiences
for the patient to learn to find the
best viewing area, fixate on objects,
or scan with that area accurately.

* Teach the patient to manage his or
her scotoma placement for efficient
reading.

* Encourage the patient continually to
use eccentric viewing.

Box 2

Instructional Components
of Near Spot Reading

* Show the patient how to maximize
the visual field (for example, hold
the pocket magnifier close to the
eye).

* Emphasize the use of eccentric
viewing with the magnifier.

* Teach general troubleshooting
techniques.

* Show the patient how to maintain
the magnifier (change batteries, if
applicable, and clean, repair, or
replace the magnifier).

Instructional components of near spot reading

The instructional components for facilitating the effective use of a pocket magnifier are described in Box 2. The essential components are scanning to locate information efficiently, maintaining orientation on the page, and interpreting visual information. Homework assignments included practicing an assortment of activities (such as reading price tags, return addresses on envelopes, labels on medicine bottles, nutritional labels, grocery lists, menus, and the amounts due on bills).

Instructional components of short-duration or portable reading

Common tasks presented in this category include reading away from home and various places within the home (like the kitchen, garage, and living room) that required portable-use devices. These devices are also useful for short-duration reading tasks. The instructional components for short-duration or portable reading are described in Box 3. The assigned homework in this category included an assortment of reading materials for reading with short-duration or portable devices, such as menus, mail, magazines, stories, and a telephone book.

Instructional components of sustained (long-duration) reading

The instructional components for facilitating the effective use of a CCTV for sustained (long-duration) reading are described in Box 4. The homework assignments in this category included an assortment of reading activities for the CCTV (for instance, reading stories, locating or reading newspaper and magazine articles, reviewing bills, and viewing photographs). Facilitating the participants' understanding of which reading device is appropriate for which reading task was emphasized.

Instructional components of writing

The instructional components specific to writing with a CCTV are included in Box 5. In addition to the essential components of near-vision tasks presented earlier, effective writing with a CCTV includes scanning or tracking to locate information, making writing-specific adjustments, and understanding the visual control of hand movements when viewing with a CCTV. Homework assignments in this area included an assortment of writing activities with the CCTV, such as practicing signatures with various space limitations, writing grocery lists, and filling out checks.

Box 3

Instructional Components
of Short-Duration
or Portable Reading

Stand magnifier

* Explain how to maximize the visual
field (for example, by moving the
eye closer to the lens).

Reading glasses

* Teach the patient how to focus the
device.

* Show the patient how to maintain
the focal distance.

Both devices

* Instruct the patient to adjust,
manipulate, and understand the
importance of a reading stand; for
example, explore different situations
when a reading stand is and is not
beneficial.

* Teach general troubleshooting
techniques.

* Emphasize the use of eccentric
viewing with the device.

* Review the effects of ambient light.

* Emphasize the importance of paced
reading to prevent fatigue.

* Maintain the magnifier or eyeglasses
(change the batteries, if applicable,
and clean, repair, or replace the
device).

Box 4

Instructional Components
of Sustained (Long Duration)
Reading

* Explain why CCTV eyeglasses that
correct presbyopia are helpful.

* Teach the patient the placement of
the CCTV in the home and the
effects of ambient light on
performance.

* Explain the proper use of CCTV
controls.

* Show the optimal setup of materials
for efficient reading.

* Emphasize the use of eccentric
viewing while reading with the CCTV.

* Teach the patient how to view
photographs with the CCTV.

* Demonstrate techniques for ease in
reading magazines, newspapers, and
telephone books.

* Teach general troubleshooting
techniques.

* Show the patient how to maintain
the CTTV (how to clean and repair
it) and provide warranty information.

Instructional components of environmental modifications

One method of increasing visual efficiency is by modifying the environment, for example, by using visual and tactile labeling systems. The environmental modifications taught to the participants are listed in Box 6. During the session on environmental modifications, the participants were given suggestions for adapting their home environments, including a handout of resources and several catalogs featuring products for people with visual impairments. An essential component of applying environmental adaptations to the home was a basic understanding of techniques to increase visual efficiency. The assigned homework in this area included opportunities to consider modifications of the home, reading a handout on environmental adaptations, and using samples of products that were provided (such as bump dots).

Box 5

Instructional Components
of Writing

* Instruct the patient in writing with a
CCTV.

* Demonstrate the efficient setup of
the CCTV for writing efficiently.

* Teach techniques for general writing.

* Teach techniques for writing checks
and completing forms.

Instructional components of distance spot reading

The instructional components for distance spot reading are listed in Box 7. In addition to the essential components for near vision described earlier, the effective use of a monocular telescope and teleloupes also involves scanning and tracking to locate information and adjusting to environmental lighting conditions. Homework assignments for the use of a monocular telescope included properly adjusting the device to view several objects at various suggested distances; tracking moving objects, such as a car; focusing by manipulating distances; determining additional uses of the device; and using the device inside stores or malls, outdoors, and at close range (to view products on shelves, for example).

Box 6

Instructional Components
of Environmental
Modifications

* Explain the use of contrast
(brightness or color) to improve
visibility.

* Teach methods for improving fighting.

* Show the patient how to change the
size of the retinal image (by using
optical devices, changing the
viewing distance, and using larger
products or labels).

* Explain how to reduce visual clutter.

Box 7


Instructional Components
of Distance Spot Reading

* Show the patient how to locate an
object through the monocular.

* Encourage the patient to practice the
use of stabilizing techniques.

* Teach two methods of focusing (turning
the eyepiece or changing distances).

* Teach focusing techniques and
strategies (prefocusing for known or
estimated distances and fine-detail
focusing).

* Demonstrate eccentric viewing with
the device.

* Teach general troubleshooting
techniques.

* Show the patient how to maintain
the monocular (to clean, repair, or
replace it).

Instructional components of sustained distance viewing

The instructional components of sustained distance viewing are described in Box 8. The homework assignments in this area included watching television, reading a directory on television, changing channels by using on-screen displays, and watching birds outside the window.

Box 8

Instructional Components
of Sustained Distance Viewing

* Emphasize focusing the teleloupes
and understanding the basic focal
ranges.

* Teach the patient how to locate
visual targets by viewing under the
carrier frame and later centering the
target in the optics.

* Teach general troubleshooting
techniques, including ambient
lighting.

* Encourage the patient to use
eccentric viewing with the device.

* Explain how to maintain the device
(repairing, cleaning, or replacing it).

* Review safety issues involving
walking while looking though the
telescopic lenses.

Results

The time required for the low vision examination was 1.1 [+ or -] 0.60 hours for the optometrist and 1.8 [+ or -] 0.60 hours for the low vision therapists. In the LOVIT model, the low vision therapists assisted the optometrist in performing the low vision evaluation to improve efficiency. The time that the therapists spent teaching lessons and reviewing homework for the 64 patients in the treatment group was 10.46 [+ or -] 2.06 hours. Table 1 presents a breakdown of the time spent on lessons, correcting or reviewing homework with the participants, and providing a preview of the session that was scheduled for the following week.

Other services that were not timed included discussing visual impairment with the veterans and their families, assisting the veterans in their homes, fitting new spectacles, repairing or refitting currently owned spectacles, setting up the CCTV in each participant's home, evaluating filters, and conducting a final reading test with the CCTV.

There were a total of 55 homework assignments (7 on eccentric viewing, 5 on the pocket magnifier, 4 on environmental modification, 10 on the stand magnifier and on reading prescriptions, 21 on the CCTV, 3 on teleloupes, and 5 on monocular telescopes) on which the participants spent 17.08 [+ or -] 8.9 hours. Compliance with homework was high; that is, 85% of the participants completed at least 80% of homework that was assigned. The time that was spent completing homework assignments is presented in Table 2.

Discussion

Previous outcomes studies frequently tested usual care or usual care plus an intervention of interest (de Boer et al., 2006; Hinds et al., 2003; La Grow, 2004; Lamoureux et al., 2007; McCabe, Nason, Turco, Friedman, & Seddon, 2000; Reeves, Harper, & Russell, 2004; Scott, Smiddy, Schiffman, Feuer, & Pappas, 1999; Stelmack et al., 2002; Stelmack, Szlyk, Stelmack, Demers-Turko et al., 2004; Stelmack et al. 2007; Wolffsohn & Cochrane, 2000). LOVIT used a different approach--a strict protocol for all aspects of the intervention, with the allowance of some flexibility for individual differences in participants (such as the use of different sizes of print to practice eccentric viewing skills before low vision devices were introduced). With a structured protocol, other researchers can replicate the study or use components of the protocols to design other studies. Clinicians can use the protocols as is, modify them for practice in different service delivery settings, or use them for educational purposes. These comprehensive treatment protocols with proved efficacy will contribute to the development of evidence-based guidelines for the care of people with low vision.

The time used by the optometrist and the low vision therapist in performing the low vision examination, the time the therapists spent providing low vision rehabilitation therapy, and the time the participants spent completing homework were itemized so that administrators, clinicians, and policy makers can use these reports to estimate the time required for the component services and the costs of conducting similar programs in the VA or the private sector and to compare the costs and cost-effectiveness of other program options to the treatment program used in LOVIT.

Because the therapy techniques used in LOVIT were adopted from or are similar to those found in low vision therapy manuals and textbooks, LOVIT provides strong evidence of the effectiveness of treatments that are available to low vision practices. LOVIT also provides strong evidence of the team approach to the delivery of low vision services that is advocated in clinical practice guidelines.

The large improvements in self-reported visual function (reading, mobility, visual information processing, visual motor skills, and overall) in the treatment group compared to the control group confirm that the low vision treatment program that was evaluated in LOVIT is effective (Stelmack et al., 2008). However, the treatment program included many components: eccentric viewing therapy; homework activities that were assigned to the participants and graded and discussed with the instructor; the provision of low vision devices, such as expensive CCTVS without charge; and a home visit to set up equipment and evaluate each participant's environment. The research design that was used in LOVIT did not allow us to determine which components of the program are necessary or sufficient to achieve the outcomes that are reported. Future studies will be needed to evaluate the essential elements of low vision care and to determine the most efficient and cost-effective practices.

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Funding for this research was provided by Rehabilitation Research and Development grant C3457 from the Department of Veterans Affairs (VA). Funding for the low vision devices that were prescribed and dispensed to the veteran participants was provided by the Department of Veterans Affairs Prosthetics Service. This article was reviewed by members of the LOVIT Study Group: Domenic Reda, statistical consultant, and Nancy Ellis, national study coordinator, at the VA Cooperative Studies Program Coordinating Center, Edward E. Hines Jr. VA Hospital; and Gary Mancil, low vision optometrist, at the Vision Rehabilitation Research Laboratory, W. G. (Bill) Hefner Veterans Affairs Medical Center.

Joan A. Stelmack, O.D., M.P.H., chief of low vision optometry, Blind Rehabilitation Service, Blind Rehabilitation Center (124), Edward E. Hines VA Hospital, 500 South 5th Avenue, Hines, IL 60141; e-mail: <[e-mail]>. Stephen Rinne, M.A., blind rehabilitation specialist-research, Blind Rehabilitation Center (124), Edward E. Hines VA Hospital; e-mail: <steve. [e-mail]>. Rickilyn M. Mancil, M.A., research health scientist, Vision Rehabilitation Research Laboratory, W. G. Hefner VA Medical Center, 1601 Brenner, Salisbury, NC 28144; e-mail: <[e-mail]>. Deborah Dean, M.A., blind rehabilitation specialist, Blind Rehabilitation Center (124), Edward E. Hines VA Hospital; e-mail: <[e-mail]>. D'Anna Moran, M.A., blind rehabilitation specialist researcher, Blind Rehabilitation Center (124), Edward E. Hines VA Hospital; e-mail: <dani. [e-mail]>. X. Charlene Tang, M.D., Ph.D., biostatistician, Cooperative Studies Program Coordinating Center, Edward E. Hines VA Hospital; e-mail: <[e-mail]>. Roger Cummings, O.D., staff optometrist, Vision Rehabilitation Research Laboratory, W. G. Hefner VA Medical Center; e-mail: <roger.cummings@ va.gov>. Robert W. Massof, Ph.D., professor, Lions Vision Research and Rehabilitation Center, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, 550 North Broadway, 6th floor, Baltimore, MD 21205; e-mail: <[e-mail]>.

Table 1
The amount of time therapists spent teaching patients and
reviewing homework.

                                       Hours per patient

Type of activity                Mean    SD    Minimum   Maximum

Lesson
  Eccentric viewing             1.67   0.55     0.55      2.75
  Pocket magnifier              0.74   0.23     0.20      1.30
  Environmental modification    1.17   0.31     0.70      2.13
  Stand magnifier               0.64   0.24     0.08      1.38
  Reading prescription          0.23   0.15     0.05      0.58
  CCTV                          3.21   1.09     0.58      5.50
  Teleloupes                    0.61   0.27     0.13      1.50
  Monocular telescope           1.16   0.32     0.25      2.08
Homework review
  Eccentric viewing             0.26   0.13     0.05      0.63
  Pocket magnifier              0.19   0.07     0.05      0.33
  Environmental modification    0.12   0.06     0.02      0.32
  Stand magnifier               0.16   0.11     0.03      0.65
  Reading prescription          0.07   0.03     0.03      0.12
  CCTV                          0.47   0.15     0.08      0.92
  Teleloupes                    0.09   0.05     0.02      0.32
  Monocular telescope           0.16   0.06     0.07      0.30
Lesson
  Mean of total hours           9.07   1.99     3.23     12.95
Homework
  Mean of total hours           1.39   0.41     0.42      2.38
Lesson plus homework
  Mean of total hours          10.46   2.06     3.65     14.07

Table 2
Mean amount of time patients spent completing homework.

                                       Hours per patient

Type of homework              Mean     SD    Minimum   Maximum

Eccentric viewing              1.40   1.23     0.05      5.88
Pocket magnifier               0.95   1.09     0.13      6.50
Environmental modification     1.24   0.85     0.17      3.87
Stand magnifier                2.85   1.84     0.33      7.95
Reading prescription           2.03   1.36     0.37      3.57
CCTV                           8.75   4.12     1.65     22.77
Teleloupes                     1.08   0.86     0.13      5.75
Monocular telescope            2.01   1.26     0.17      4.92
Mean total for all homework   17.08   8.90     0.05     48.72