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Surgical Removal vs Observation for Idiopathic or Ocular Histoplasmosis Syndrome–Associated Subfoveal Choroidal NeovascularizationVision Preference Value Scale Findings From the Randomized SST Group H Trial: SST Report No. 17
Submacular Surgery Trials Research Group*
Arch Ophthalmol. 2008;126(12):1626-1632.
ABSTRACT
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Objective To determine whether patients receiving observation vs surgery for subfoveal choroidal neovascularization that was idiopathic or associated with histoplasmosis differed in preference values assigned to their health and vision status.
Methods Before and after enrollment, patients rated their current vision on a scale from 0 (blind) to 100 (perfect vision) and rated blindness and perfect vision on a scale from 0 (dead) to 100 (perfect health and vision). Scores for current vision were converted to a preference value scale (0 represents death; 100, perfect health and vision).
Results In 170 patients, no significant difference existed between the observation and surgery arms in median vision preference values at baseline (74 vs 70) or at the 12- (74 vs 78) or 24-month follow-up (77 vs 73) (P > .05). Preference values did not differ between arms for subgroups defined by age, unilateral vs bilateral choroidal neovascularization, or good vs poor baseline visual acuity.
Conclusions Submacular surgery was no better than observation in the preference values patients assigned to their health status, despite previously reported improvements in vision-specific quality of life.
Trial Registration clinicaltrials.gov Identifier: NCT00000150
Clinical Relevance Ophthalmologists should consider the effects on different measures of quality of life when determining treatment for patients similar to those in the Submacular Surgery Trials Group H Trial.
INTRODUCTION
Subfoveal choroidal neovascularization (CNV) has serious effects on vision. In adults younger than 60 years, the most common causes of CNV are the ocular histoplasmosis syndrome and idiopathic occurrence.1-2 Many aspects of their lives, including employment, may be affected by their vision problems and by treatments that may be administered. Although neovascular ocular histoplasmosis and idiopathic CNV often remain unilateral, they nonetheless threaten the vision- and health-related quality of life of these middle-aged adults.3-5
In a randomized trial of observation vs surgical removal of subfoveal CNV lesions that were idiopathic or associated with ocular histoplasmosis (Submacular Surgery Trials [SST] Group H Trial), 46% of the eyes in the observation arm and 55% of the eyes in the surgery arm had a successful clinical outcome, defined as 24-month visual acuity that was better or no more than 1 line worse than at baseline.6 The difference was not statistically significant except in 1 prespecified subgroup in whom visual acuity in the study eye was worse than 20/100 at baseline (success ratio, 1.53; 95% confidence interval, 1.08-2.16). However, vision-targeted quality of life improved more after submacular surgery than after observation for the overall group.7 On average, patients in the surgery arm had 4-point larger improvements in their scores on the National Eye Institute Visual Function Questionnaire (NEI-VFQ) than patients in the observation arm (confidence interval for the difference, 1-8 points). To improve understanding of the discrepancy between an improvement in vision-targeted quality of life and the lack of a significant difference in clinical outcome, we explored how the patients in the SST Group H Trial felt about the effects of CNV on their overall quality of life over time. Previous studies have shown that decreased visual acuity was associated with a decrease in the preference values that patients assigned to their health and vision status,8-11 where preference values refer to how people feel about the desirability of a health state.12
The purpose of this analysis was to determine whether the patients in the 2 arms of the SST Group H Trial had different changes in the preference values that they assigned to their health and vision status. Because preference values may differ by age and the presence of unilateral vs bilateral CNV,8 and because of the difference in visual acuity outcomes by baseline visual acuity in the SST Group H Trial,6 we also compared findings by treatment arm within these subgroups of patients.
METHODS
An independent Data and Safety Monitoring Committee approved the methods proposed for the SST before patients enrolled in the SST Group H Trial starting April 1, 1997. Institutional review boards at participating institutions approved the study design and consent forms. All patients gave written consent before enrollment and random treatment assignment.
Many of the methods used in the SST Group H Trial have been published previously.5-8 The Submacular Surgery Trials Manual of Procedures13 and the SST Forms Book14 provide details regarding study methods.
PATIENT ELIGIBILITY AND ENROLLMENT
A previous report6 contains details of eligibility requirements for patients and eyes, clinical evaluation procedures, and data collection. Patients were eligible to participate in the SST Group H Trial if they were 18 years or older, had new or recurrent subfoveal CNV lesions with evidence of classic CNV on fluorescein angiography, and had best-corrected visual acuity of 20/50 to 20/800, inclusive, in at least 1 eye (the study eye). The visual acuity of the nonstudy eye had to be light perception or better. Patients had to agree to complete telephone interviews before enrollment and at scheduled times after enrollment. Enrollment and random treatment assignment did not take place until the baseline interview was completed with an interviewer at the SST Coordinating Center, Baltimore, Maryland.
Patients were invited to participate if the examining ophthalmologist judged them to be eligible. The consent and enrollment processes are described elsewhere.6 Randomization was stratified by enrolling center. Patients received a schedule of dates for future interviews and examinations and the permissible intervals during which each one could be completed.
INTERVIEW METHODS
We used the 3-item SST Vision Preference Value Scale (VPVS) to assess the value patients placed on their current vision and health relative to perfect vision or complete blindness, with the same 3 items that were described in detail in an earlier publication.8 The VPVS used a rating scale technique that has had good test-retest reliability and internal consistency in most studies.12, 15 In addition, the rating scale technique can be expected to yield reasonable response rates because it is relatively easy for most people to understand. It yields reliable and valid results even without an in-person interview or visual aids.15 These considerations were important because they allowed us to administer the instrument centrally by telephone without requiring visual aids that might not be seen by patients with bilateral loss of central vision.
Telephone interviewers administered the VPVS by asking patients to rate their current vision, using both eyes, on a rating scale from 0 (completely blind) to 100 (perfect vision). As in previous studies,8, 10 complete blindness and perfect vision were the scale anchors because it was easier for an individual to rate a visual state on a scale defined in terms of vision than on a scale defined in other terms such as death and perfect health. The interviewers then asked the patients to rate what they imagined it would be like to be completely blind in both eyes (with otherwise the same health), using a scale from 0 (death) to 100 (perfect health). Finally, patients were asked to rate what it would be like to have perfect vision without any other change in health, again using a scale from 0 (death) to 100 (perfect health). These 3 questions permitted conversion of the first rating on the vision-only scale to preference values on a scale from death to perfect health and vision. For example, if a patient rated current vision as 50 on the vision scale, and rated complete blindness (with otherwise same health) as 30 and perfect vision (with otherwise same health) as 90 on the scale measuring death to perfect health, the final preference value for the current vision and health state would be 60 on that scale. By asking patients to assign a preference value to perfect vision with their otherwise same current health, we were able to adjust for the perceived effects of coexisting health problems on ratings of their overall health. This approach is consistent with our previous work in measuring preference values associated with eye disease.8, 10
The interviews included the following 3 validated instruments for assessing health-related quality of life: (1) the 39-item NEI-VFQ16-18; (2) the 36-item Short Form Health Survey (SF-36)19-20; and (3) the 14-item Hospital Anxiety and Depression Scale (HADS).21 The NEI-VFQ was designed for patients with vision-limiting or vision-threatening conditions. The items yield an overall score and scores on 11 subscales that address different aspects of visual function. Overall scores on the NEI-VFQ have a range of 0 (worst score) to 100 (best). The SF-36 measures general health status and health-related functioning. The SF-36 items are combined to create 8 subscales that can be combined further to create 2 summary scales.20 The summary scale developers calibrated the scores on the physical and mental component summary scales to have means (SDs) of 50 (10) points in the general US population.20 Higher scores on the SF-36 summary scales indicate better perceived health status. The HADS has 2 scales (anxiety and depression, 7 items each) with scores that range from 0 (best score) to 21 (worst). In the interviews, the SF-36 preceded the HADS, and the NEI-VFQ preceded the questions used to determine the preference value, but a computer program randomly selected the SF-36 or the NEI-VFQ to be administered first. After October 9, 1997, all patients enrolled in the SST were asked the preference value questions in addition to the other health-related quality of life questions.
Although patients were not masked to treatment assignment in this surgical trial, all interviews were conducted by trained interviewers who were masked to the study eye, the clinical trial, the treatment arm, and clinical data. Interviewers used a computer-assisted system that interacted with the study database to confirm identifiers assigned to patients so that interview data could be integrated with the clinical data for each patient.
All patients were scheduled for follow-up interviews at 6, 12, and 24 months after enrollment. Patients who enrolled by September 30, 2000, were scheduled for a 36-month interview, and those who enrolled by September 30, 1999, also were scheduled for a 48-month interview. The last interviews for all patients who had not completed a 48-month interview were conducted during the final year of follow-up that began on October 1, 2002.
BASELINE CLINICAL DATA COLLECTION
Clinical data collection at baseline and during follow-up is described elsewhere.6 Baseline data collection included measurement of the best-corrected visual acuity, reading speed, and contrast threshold of each eye according to standard protocols. Baseline stereoscopic color photographs of the macula and disc of each eye and a film-based fluorescein angiogram were forwarded to the SST Photograph Reading Center, Baltimore, for documentation of characteristics of the eyes and subfoveal lesions.
We used best-corrected visual acuity measurements before enrollment to classify patients by the visual acuity of the study eye (20/50 to 20/100 vs 20/125 to 20/800), a grouping specified during trial planning. Patients were classified as having unilateral or bilateral neovascular disease based on masked central interpretations of baseline photographs.6
QUALITY ASSURANCE
To standardize the interviews, the chairperson of the SST Patient-Centered Outcomes Subcommittee led a training session for interviewers before the trial began and at least once a year thereafter. The interviewers met periodically during the first years of the trial to reach agreement on issues of interview administration. The SST Patient-Centered Outcomes Subcommittee met twice yearly to review interview administration and preliminary data (combined across treatment arms). Because the interviewers found that some patients could not answer the preference value questions, the SST Patient-Centered Outcomes Subcommittee made minor simplifications on 2 occasions to the questions used to determine the VPVS, as described in a previous report.8 Previous studies12, 22 have found that up to 30% of the general public has difficulty understanding scaling techniques for measuring preference values. As previously reported, our analysis of all SST baseline interviews found significant, albeit small, differences in the demographic and clinical characteristics of those who did and did not give usable answers to the preference value questions.8 Those who were not able to answer the questions were slightly older, more often were retired, had somewhat worse vision in the better eye, more often had CNV in the fellow eye, and had, on average, lower physical component summary scores and higher mental component summary scores on the SF-36.
STATISTICAL DESIGN
In the SST Group H Trial, best-corrected visual acuity was the primary clinical outcome for comparison of study arms. The target sample size of 240 patients was expected to provide 218 patients with visual acuity measured at the 24-month examination.6 The enrolled sample yielded 170 patients with usable baseline and follow-up VPVS scores, including 81 in the observation arm and 89 in the surgery arm. Using the observed standard deviations in the VPVS scores in the study arms, we estimated that this sample size had at least 80% power to detect or to rule out a 10-point difference between study arms in the VPVS score but less than 30% power to detect or to rule out a 5-point difference.
Owing to funding constraints and other considerations, accrual ceased on September 30, 2001, and scheduled follow-up ended on September 30, 2003.6 Thus, all patients were eligible for interviews 24 months after enrollment, but only patients who enrolled by September 30, 2000, were eligible for 36-month interviews. Only those who enrolled by September 30, 1999, were eligible for 48-month interviews (the limited data at 48 months are not presented in this report). Some patients enrolled before the VPVS was incorporated into the interview and thus have no baseline scores for this instrument.
DATA ANALYSIS AND STATISTICAL METHODS
To assess differences in patient characteristics between study arms, we used the unpaired t test, the Wilcoxon rank sum test, or the  2 test for homogeneity. The NEI-VFQ, SF-36, and HADS scores were calculated using the recommendations of the developers, except that a scale score was not calculated in the few instances in which half of the items that make up a scale had not been answered. For the NEI-VFQ driving scale, patients who responded that they had stopped driving because of vision (17 at baseline and 14 at the 24-month interview) were given a score of 0. The HADS developers proposed the following scores to classify patients with respect to anxiety and depression: 0 to 7, noncases; 8 to 10, doubtful cases; and 11 or greater, definite cases.21
We summarized the distribution of responses to each of the VPVS questions by calculating means, medians, and interquartile ranges. Standard box and whisker plots were created to provide summaries of the distributions. To determine whether preference values differed by study arm at baseline or at follow-up times for the total group and for subgroups, we used the unpaired t test or the Wilcoxon rank sum test. To determine whether the change in preference values differed by study arm at follow-up times for the total group and for subgroups, we used the unpaired t test because changes in scores tended to be distributed normally. We compared the change scores directly, rather than the trajectory of change scores, for ease of interpretation. Because the baseline VPVS scores did not differ significantly between groups, consistent with random treatment assignment, we did not adjust for baseline scores in the analysis. P < .05 was deemed to indicate statistical significance. No adjustment was made for multiple comparisons.
We analyzed data from all interviews through the 36-month interview completed by September 30, 2003. We analyzed data from each patient with the study arm to which he or she was assigned at the time of enrollment (intent-to-treat analysis). We did not impute scores for missed interviews. For display purposes, we used lines to connect median or mean scores from cross-sectional distributions at each interview time, although not all patients completed all scheduled interviews. The analyses were performed using commercially available software (SAS, version 8; SAS Institute Inc, Cary, North Carolina).
RESULTS
When accrual ended on September 30, 2001, 225 patients had enrolled in the SST Group H Trial; 113 patients had been assigned to the observation arm and 112 to the surgery arm. Nineteen of these patients enrolled before the VPVS was included in the baseline interview. Of the 206 patients interviewed, 15 (7.3%) were unable to answer 1 or more of the preference value questions. Also, 16 patients (7.8%) assigned a value to complete blindness that was equal to or greater than the value they assigned to perfect vision, suggesting that they did not understand the questions. Five additional patients had a usable baseline VPVS score without usable follow-up scores. Baseline interviews were conducted by 9 different interviewers. Three interviewers conducted 133 of the 170 baseline interviews (78.2%).
CHARACTERISTICS OF PATIENTS AT STUDY ENTRY
Of the 170 patients who had usable baseline and follow-up VPVS scores, 81 were in the observation arm and 89 in the surgery arm. The Table presents their characteristics at baseline. Study arms were well balanced with respect to all characteristics examined, except for a few small differences that were not statistically significant (P > .05). Compared with the surgery arm, the observation arm had a few more patients classified as having definite anxiety (16 patients [20%] vs 11 [12%]) and slightly fewer patients with better eye visual acuity of 20/40 or better (64 patients [79%] vs 79 [89%]). The CNV lesions were bilateral in 21 patients in the observation arm (26%) and 20 in the surgery arm (22%). Ocular histoplasmosis was the underlying cause of the CNV lesion for 85% of both study arms (69 patients in the observation arm and 76 in the surgery arm). All patients had the assigned treatment.
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Table. Baseline Characteristics of Patients With Usable Vision Preference Value Scale Scores, by Treatment Arm, in the SST Group H Trial
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The observation and surgery arms had similar baseline distributions of VPVS scores (P > .05) for the total group (mean, 70 vs 68) and for the subgroups 50 years or younger (mean, 71 vs 69), older than 50 years (mean, 68 vs 65), with unilateral CNV (mean, 72 vs 69), with bilateral CNV (mean, 63 vs 63), with baseline study eye visual acuity 20/100 or better (mean, 71 vs 70), and with baseline visual acuity worse than 20/100 (mean, 68 vs 65) (eFigure 1).
COMPLETION OF FOLLOW-UP INTERVIEWS
Patients in the observation arm completed 237 of 312 follow-up interviews expected (76.0%). Patients in the surgery arm completed 281 of 344 follow-up interviews expected (81.7%). The total numbers of interviews during follow-up were 144, 143, 120, and 111 at 6, 12, 24, and 36 months, respectively. Two interviewers administered 436 of the 518 follow-up interviews (84.2%).
VPVS SCORES AT FOLLOW-UP INTERVIEWS
The median VPVS score did not differ significantly between the observation and surgery arms at 6, 12, 24, or 36 months of follow-up for the total group or any of the specified subgroups, except for small differences at 12 months in patients who were older than 50 years or who had bilateral CNV (eFigure 2).
CHANGES IN VPVS SCORES FROM BASELINE TO FOLLOW-UP INTERVIEWS
The mean change in VPVS score did not differ significantly between the observation and surgery arms at 24 months, prespecified as the time for the primary outcome assessment, but did differ at 12 months for the total group (mean decrease of 2 with observation and mean increase of 4 with surgery; P = .04) (eTable). The Figure shows that the mean changes in the VPVS score were less than 10 at all times for the total group and each subgroup. We found no significant difference between the surgery and observation arms in mean change scores from baseline to 24 months of follow-up for any of the subgroups shown in the Figure. The only statistically significant difference was in the mean change in scores observed at 12 months in patients with a baseline study eye visual acuity worse than 20/100 (mean decrease of 3 with observation and mean increase of 7 with surgery; P = .01).
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Figure. Mean change in Submacular Surgery Trials Vision Preference Value Scale (VPVS) scores from baseline to scheduled follow-up times, by study arm, for all patients (A), patients 50 years or younger at baseline (B), patients older than 50 years (C), patients classified as having unilateral choroidal neovascularization (CNV) at baseline (D), patients classified as having bilateral CNV (E), patients with visual acuity (VA) of 20/100 or better in the study eye at baseline (F), and patients with VA worse than 20/100 in the study eye (G). The best possible score on the VPVS is 100; the worst possible score, 0. Positive changes denote improvements from baseline scores.
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COMMENT
We found no statistically or clinically significant difference between the observation and surgery arms in the preference values that patients assigned to their health and vision status at the 24-month interview. The only significant differences in preference values suggesting a possible benefit after surgery compared with observation were at the 12-month interview for the total group, paralleling the previously reported visual acuity findings,6 and for the subgroup that had baseline visual acuity of 20/125 or worse.
In the SST Group H Trial, we collected outcome data on visual acuity, vision-targeted quality of life, and overall health-related quality of life, in addition to the data on preference values. When we compared the preference value findings with the visual acuity findings, we noted that the preference value results were consistent with the absence of any significant difference in visual acuity between the study arms for the total group after 24 months of follow-up. The preference value results also were consistent with the lack of any statistically significant difference between the surgery and observation arms in the generic measures of health-related quality of life, including the SF-36 and HADS. It is not surprising that submacular surgery was not associated with improvement in the SF-36 or the HADS because generic measures of health-related quality of life often have limited sensitivity for detecting improvements after treatment of disease.22-25
As we reported previously,7 submacular surgery was associated with greater improvement in vision-targeted quality of life, as measured by the NEI-VFQ, when compared with observation. At the 24-month follow-up, the NEI-VFQ scores had improved more with surgery than with observation, with the largest differences seen in the role difficulties and dependency subscales.7 The difference in NEI-VFQ scores between the surgery and observation arms was largest for the small subgroup that had bilateral CNV at baseline.7 However, we observed no significant difference between the study arms in the VPVS scores at 24 months for the total group or for the patients with unilateral or bilateral CNV.
How can we reconcile the discrepancy between the NEI-VFQ and VPVS findings? First, we must remember that the NEI-VFQ measures vision-targeted aspects of health-related quality of life that are not captured by generic measures of quality of life, whereas the VPVS measures how a patient feels about his or her vision and other aspects of overall health status, taking into consideration the health- and vision-related domains of functioning important to the patient. The importance of these domains varies among patients, even for patients like those in the SST Group H Trial, most of whom had little comorbidity. The VPVS may be less sensitive than the NEI-VFQ for identifying changes directly related to treatment of the ocular condition. This explanation is consistent with previously reported data on the responsiveness of preference values and other measures of health status. For example, Rosen et al22 found that the Quality of Well-Being Scale, a preference-weighted general health status measure, was less sensitive than the 14-item Visual Function Index, a vision-specific measure of health-related quality of life. Second, the observed differences in NEI-VFQ scores between the surgery and observation groups were modest, with a mean increase of 8.3 in the surgery arm compared with a mean increase of 4.1 in the observation arm.7 Even for the NEI-VFQ subscales that had the largest differences between treatment arms, the differences were less than 10 points.7 Although a decrease in NEI-VFQ scores of 4 to 16 points is associated with a 3-line decrease in visual acuity,26 the differences observed in this trial may be too small to be associated with a significant difference in the change in preference values. The VPVS (and NEI-VFQ) scores were low enough at baseline to suggest that CNV already had a dramatic effect on how patients felt about their vision and overall health. Although one might expect the VPVS scores to fall without treatment of the CNV, the VPVS scores did not decrease significantly in the observation arm of the study during the 3-year follow-up. This suggests that, once patients have had enough visual impairment to consider surgical treatment of CNV, it may take a large subsequent change in visual functioning to alter how they feel about their functional status. In the absence of masking of patients to treatment assignment, it is possible that patients perceived they were better off after surgery despite a lack of change in visual acuity. However, we would expect such perceptions to affect preference values at least as much as the responses to the NEI-VFQ, so we doubt this explains any discrepancy between the VPVS and NEI-VFQ results. The consistency of our preference value findings with the visual acuity findings could be misleading, because even visual acuity has some limitations as a measure of the effects of CNV. Other clinical measures should be considered, such as contrast threshold and reading speed. As previously reported, we found no difference between the surgery and observation arms in the mean change in contrast threshold of study eyes from baseline to the 24-month follow-up examination, but we found a significant difference in reading speed at the 3- and 6-month examinations that favored surgery.6 Although it is tempting to use our preference value findings to discount the reported differences in NEI-VFQ scores between the surgery and observation arms, the NEI-VFQ measures aspects of visual functioning that were not assessed directly by any of the other measures used in this trial.
One of the most important limitations of this analysis is that a subset of study participants had difficulty answering the questions that we used to estimate preference values. However, 85% of our study participants were able to give usable answers to the VPVS questions,8 which compares favorably with the experience of other investigators who have sought to measure patients' preference values for specific conditions.9-10,12, 27 Those previous studies found that 10% to 30% of study subjects have difficulty answering questions that involve quantification of their preference values. We modified the wording of the questions over the course of the study to minimize the number of study subjects who could not provide usable answers. With the modified wording, we saw a slight but nonsignificant trend toward a decrease in the percentage of patients unable to answer the questions.8 The estimates of patients' preference values in the SST were similar regardless of the minor differences in wording of the questions. The use of 9 interviewers may have introduced some variation in the preference values, but this is unlikely to be significant because of the scripted nature of the VPVS. Although the use of death and perfect health and vision as anchors of the VPVS may increase the variance in the measure, our previous work demonstrated that the VPVS had reasonable construct validity.8
As we noted, the VPVS was added to the interview after 19 of the 225 patients (8.4%) had enrolled, completed the baseline interview, and been assigned randomly to a treatment arm, thus reducing the number available for assessing 2-year changes in VPVS scores. In addition, 5 (2.4%) of the 206 patients who completed a baseline VPVS interview did not complete a 2-year interview, further reducing the analysis sample.
Another important issue is that the VPVS yielded a wide distribution of scores with an interquartile range of 51 to 80 on a scale from 0 to 100.8 With such a wide distribution of scores that are not normally distributed, it is more difficult to detect significant differences between study groups. However, the observed variability in VPVS scores reinforces the importance of measuring them because they tend to vary so much, even among patients who have a similar clinical condition.
We conclude that submacular surgery was no better than observation in terms of the preference values that patients assigned to their health and vision status during follow-up, indicating that they do not feel better about their overall health-related quality of life. In the absence of significant improvement in visual acuity, the VPVS showed no significant improvement in the preference values that were associated with the previously reported improvements in vision-specific quality of life after submacular surgery. Ophthalmologists should consider the effects of submacular surgery and other treatments on different measures of health-related quality of life when determining treatment options for patients similar to those who participated in the SST Group H Trial. Given that preference values vary widely among individuals, patients may want to weigh all of the reported effects of treatment on visual acuity, vision-targeted quality of life, and preference values when considering submacular surgery or other treatment for subfoveal CNV, whether idiopathic or associated with the ocular histoplasmosis syndrome.
AUTHOR INFORMATION
Correspondence: Eric B. Bass, MD, MPH, Department of Medicine, The Johns Hopkins University, 1830 E Monument St, Room 8068, Baltimore, MD 21287 (ebass{at}jhmi.edu).
Submitted for Publication: July 19, 2007; final revision received June 10, 2008; accepted July 23, 2008.
Financial Disclosure: Dr Bressler's employer, The Johns Hopkins University, but not Dr Bressler, receives funding for consulting services and research efforts provided by Dr Bressler to Novartis Pharma AG, QLT Inc, Eyetech Pharmaceuticals, Inc, and Genentech. The terms of these arrangements are managed by The Johns Hopkins University according to its policies regarding potential conflicts of interest.
Funding/Support: The Submacular Surgery Trials are sponsored by the National Eye Institute, National Institutes of Health, US Department of Health and Human Services, Bethesda, Maryland, through cooperative agreements U10 EY11547, EY11557, and EY11558 with The Johns Hopkins University.
*Submacular Surgery Trials Research Group Authors: Members of the SST Patient-Centered Outcomes Subcommittee served as representatives of the SST Research Group on the Writing Committee for this report and include Eric B. Bass, MD, MPH; Marta M. Gilson, PhD; Carol M. Mangione, MD, MSPH; Barbara S. Hawkins, PhD; Päivi H. Miskala, PhD; Ashley L. Mann, MS; and Neil M. Bressler, MD. Documentation of approval of the manuscript submitted for publication by the members of the SST Research Group is on file at the SST Coordinating Center in Baltimore. A list of the members of the SST Research Group who contributed data for this report appears in Arch Ophthalmol. 2004;122(11):1609-1610.
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