Assessment of Functional Vision Score and Quality of VisionVision-Specific Quality of Life[JH1] in Individuals with Retinitis Pigmentosa

Abstract

Objective: To determine the relationship of the American Medical Association (AMA) guidesguidelines’ functional vision score (FVS) and vision-specific quality of life in retinitis pigmentosa (RP) patients, using the National Eye Institute’s Visual Functioning Questionnaire (NEI-VFQ 25). in retinitis pigmentosa (RP) patients.

Design: A cross-sectional study

Participants: One hundred and twelve patients (224 eyes) with RP participated in the study.[JH2]

Methods: We measured the best-corrected visual acuity (BCVA), conducted a fundus examination, as well as Goldmann perimetry, and collected the self-reported NEI-VFQ 25 from the subjects. The FVS was calculated byusing the functional field score (FFS) and the functional acuity score (FAS), according to the AMA guidesguidelines. The Ccorrelations of the VFQ composite scores to the FVS, FFS and FAS were determined using correlation and regression analyses.

Main Outcome Measure: Correlations of the VFQ composite scores to the FVS, FFS and FAS.

Results: Significant correlations of the VFQ composite scores to the FVS (r=0.60, p<0.001), FFS (r=0.50, p<0.001) and FAS (r=0.57, p<0.001) was found. The FVS was a better predictor of the RP patients’ NEIVFQ [JH3] composite score than the FFS andor FAS. in RP patients. Also, the FFS was more highly correlated to the FVS (r=0.92, p<0.001) than was the FAS (r=0.66, p<0.001). According to the regression analysis, the VFQ composite score was more affected more by the FFS (p=0.02) than the FAS (p=0.08) in the better visual acuity (VA) group (log MAR < 0.6), whereas, it was affected more by the FAS (p=0.008) than the FFS (p=0.09) in the worse VA group (log MAR ≥ 0.6).

Conclusions: The AMA Guidesguidelines’ FVS was a better predictor of the RP patients’ self-reported VFQ composite score than the FFS andor the FAS. in RP patients. The VFQ composite score was more affectedaffected more by the FFS in the better VA group, whereas, it was affected more by the FVS in the worse VA group.

Key words: AMA Guidesguidelines, Functional visualVision acuityScore (FVS)[JH4] , NEI-VFQ[JH5] 25, Retinitis p[JH6] igmentosa.

Introduction

Retinitis pigmentosa (RP) refers to groupa type of hereditary retinal degeneration.; whichthat is characterized by nyctalopia, intraretinal bony specule pigmentation, narrowing of the retinal vessels, rod-cone dysfunction inas determined by electoretinogram and progressive visual field loss that leadsleading to legal blindness.¹ Impaired vision can be evaluated by measuring of visual acuity (VA) andor by visual field test, according to the American Medical Association (AMA) guidelines.² However, these scales wereare of limited value forin evaluating of vision-specific quality of life. associated vision. Hence, several studies ^3-6 have been investigatedconducted to document visual function and measurement formeasure performance in RP patients. The National Eye Institute’s Visual Functioning Questionnaire (NEI-VFQ 25) composite scores were suggested for evaluating of quality of life related visionvision-specific quality of life, and the reliability of this method was proved in previous studies on chronic diseases (glaucoma, ARMD)^7,8. However, thesethose studies were interestinterested on mainly in the VFQ composite score,; also, an assessment of the AMA guidesguidelines’ functional vision score (FVS)⁹ was not performed, andand neither was the VFQ test was not performed yetused forwith RP patients. To our knowledge, our study isoffers the first report of determination of the correlations of functional vision scoresFVS to life of quality related visionvision-specific quality of life, (NEI-VFQ 25) in RP patients, using the NEI-VFQ 25.

The purpose of this study was to determine the correlations of functional vision scores to quality of life related vision in cases of RP.[JH7]

Materials and Methods

We enrolled 112 volunteers (66 males, 46 females) with RP, ranging in age from to 16 to 85 years, who were members of the Korean retintis pigmentosa society . A Korea National RP survey was performedconducted at the Seoul National University Hospital retinal clinic from July to December 2006. All recruited RP patients; diagnosis RP was diagnosed in the recruited patients was performed on the basis of a fundus examination, Goldmann perimetry, and a complete electroretinographic evaluation according to the International Society for Clinical Electrophysiology of Vision (ISCEV)’s parameters. Patients with hearing impairment (Usher syndrome), or other systemic diseases were excluded., and those who so desired were allowed to drop out of the study. If they refused to further examination on procedure of study, they could freely drop out study. Our Institutional Review Board (IRB) approved the study protocol, informed consent was obtained from all of the subjects, and all procedures used were consistent with the tenets of the Helsinki Declaration. All of the patients underwent a thorough ophthalmologic examination including Best-Corrected Visual Acuity best-corrected visual acuity (BCVA) measurement, binocular indirect ophthalmoscopy, a fundus examination, and Goldmann perimetry. In case of diagnosis of RP was not definiteIf a definite diagnosis of RP could not be made, an electroretinogram was performed.

Visual acuity measurement and Visual field examination

The Best-corrected visual acuity (BCVA) werewas measured using Snellen Visual aAcuity Charts and converted into a logarithm of the minimum angle of resolution (log MAR) VA scale. Monocular visual fields were measured by Goldmann perimetry using the Ⅲ-4-e target at a standard black ground[JH8] luminance with a trial lens. calculated with trial lens. Along each meridian, the target was presented from a position of non-seeing to seeing, moving from the meridian in a systematicsystematically clockwise. All of the BCVA and perimetry measurements and perimetry were performed by skillfulskilled technicians.

Functional Assessment from the guidesguidelines

The American Medical Association (AMA) published guidelineguidelines^10,11 in the guides to the evaluation of permanent impairment. The FVS is calculated from the functional acuity score (FAS) and the functional field score (FFS)^10,11. Visual acuityVA measurements are converted to a visual acuity score (VAS). The weighted average of three VASs for each of field is used to calculate the FAS: for the person by determining the a weighted average of the three VAS’s:.

FAS = (VAS_OD + VAS_OS +3 X VAS_OU) /5.

To evaluate the FFS, the visual field score (VFS) for the right monocular field (VFS_OD), the left monocular field (VFS_OS), and the binocular field (VFS_OU) are first scored separately:

FFS = (VFS_OD + VFS_OS + 3 X VFS_OU)/5.

The Functional acuityFAS and functional field scoreFFS are then multiplied to yield the FVS.:

FVS = FAS X FFS /100.

Self-report Questionnaire (NEI-VFQ 25)

The NEI-VFQ 25-item version, plus appendix questions^7,8 (a total of 39 items), was administered by skillfulskilled interviewers and scored in the standard manner. There are Ttwelve subscale scores and one composite score. The NEI-VFQ 25 composite score is the average of all available subscales except general health, whichand was suggested as the vision-targetedvision-specific health related quality of life indicator by the National Eye InstituteNEI (Table 1).

Statistical analysis

The Ccorrelations of the NEI-VFQ 25 composite score to the FVS, FFS and FAS waswere analyzed by Pearson’s correlation test. A Rregression analysis was performed to determine of the better predictor of vision-specific quality of life related vision score among the FVAFVS, FFS, and FAS. As the mean log MAR was 0.6, we dividedivided the patients into two groups according to log MAR VA 0.6that value;: the better VA group (logMAR < 0.6), and the worse VA group (logMAR ≥ 0.6). In each group, the relationship of the VFQ compositioncomposite score to the FVS, FFS, and FAS was evaluated, and a regression analysis was performed. Statistical analyses were performed using SPSS v.12.0 software (SPSS Inc., Chicago, IL), and two-sided P values of <0.05 were considered statistically significant.

Results

As stated above, there were One hundred-twelve112 enrolled RP patients were enrolled (66 males, 46 females) ranging in age from 16 to 85 years. The , mean agemean age of the subjects was 37.2 ± 13.2 years,. ranging in age from to 16 to 85 years. Their Visual acuityVA ranged from -0.08 to 2.3 log MAR. And The demographic and descriptive statistics for the clinical measures of vision wasare describedlisted in Table 2.

Significant correlations of VFQ composite score to FVS (r=0.60, p<0.001), FFS (r=0.50, p<0.001) and FAS (r=0.57, p<0.001) waswere found (Figure 1). The FVS was a better predictor of the NEI VFQ[JH9] composite score than the FFS andor FAS. in RP patients.[JH10] Also, the FFS was more highly correlated to the FVS (r=0.92, p<0.001) than was the FAS (r=0.66, p<0.001) was (Table 3). According to the regression analysis, the VFQ was more affected more by the FFS (p=0.02) than the FAS (p=0.08) in the better VA group (log MAR < 0.6), whereas, it was affected more by the FAS (p=0.008) than the FFS (p=0.09) in the worse VA group (log MAR ≥ 0.6) (Table 4).

Discussion

Our results indicate that in RP patients, the AMA-guides guidelines’ FVS valuescores isare highly correlated to those of the self-report questionnairesVFQ, in RP patients. Aand that the FFS wasis a better predictor forof the FVS than the FAS. The Rresults of the present study³ correspond with those of thean earlier study, which related reported that the level of visual acuityVA and visual field was correlated significantly with actual task performance in RP patients. Several other studies^6,12 on evaluating of the performance of RP patients demonstrated that reading performance was correlated with contrast sensitivity, visual acuityVA and visual field, and that driving performance was the primary correlate of visual field loss. To assess performance function,[JH11] sSeveral studies^7,8,9 were performed by evaluating withhave used both the AMA FVS and self-report questionnairesthe AMA VFQ. or AMA-guides FVS. OnAccording to their results, the NEI-VFQ was to beis a reliable, valid method andthat should be a useful tool for group-level comparisons of vision targeted,vision-specific health-related quality of life in clinical research. Also, The AMA guides FVS washas also been found to be a better predictor of self-reported vision targetedvision-specific quality of life. However, thesethese studies ^9,13,14 on assessing performance scale[JH12] weredid not focus on RP patients,; our study, in fact, confirmed that in RP patients, the FVS value is highly correlated to NEI-the VFQ. in RP patients. In accordance with our results, Szlyk, et al. reported that in RP, self-reporting wasis strongly correlated with actual task performance in RP⁵. They evaluated the correlation of reading composite scores with contrast sensitivity, whereas, in our study, we used the AMA-guides FVS, and VFQ composite score.

In presentour[JH13] study, as previously mentioned, the VFQ was more affected more by the FFS than the FAS in the better VA group, whereas; it was affected more by the FAS than the FFS in the worse VA group. We speculated that these findings couldmight result fromreflect the fact that RP is a disease withmanifesting progressive visual field loss. As Berson et al. have suggestedsuggested that overall the visual field is lost at a rate of about 4.6% of the remaining visual field was lost per year¹⁵. Massof et al. proposedproposed that the visual field shrankshrinks approximately 50% over 4.5 years¹⁶. In any case, in typical RP, the rate of progression of visual field loss is usually slow and relentless. However, our resultfinding of differences of FFS and FVAFVS accordingwith regard to VA are not consistentinconsistent with the fact that in RP, central vision might not remain good until the peripheral field is lost in RP. In other words, central vision might begin to deteriorate before the peripheral field is completely lost; in other words, central vision can be seriousseriously affected in early-stage RP¹⁷.. Cystoid macular edema¹⁸, diffuse retinal vascular leakage¹⁹, and retinal fibrosis can be occur in the course of the disease. course. Moreover, over a few months, the visual field maycan change dramatically over a few months in RP. Sanderberg, et al. has beenhave reported that estimated that the mean annual rate of decline of ocular function wereis 1.2 % for visual acuityVA and 1.9% for visual field in atypical form[JH14] RP, which is termed pericentral RP²⁰.

The limitations of Oour study has limitations include the fact that, as it iswas designed to be a cross-sectional study, we could not postulated of the disease course of RP,; andalso, thatbecause the enrolled patients wererepresented various groupforms of RP[JH15] , it could be a factor of selection bias could be a factor. AlthoughDespite these limitations, our study is the first study that to determine the correlation of FVS to life of quality related visionvision-specific quality of life in a relatively large grouping of RP patients. with relative large study. In conclusion, for the RP patients, the AMA Guidesguidelines’ FVS was a better predictor of the self-reported VFQ than the FFS andor the FAS. in RP patients. The VFQ was more affected more by the FFS in the better VA group, whereas, it was affected more by the FVS in the worse VA group.

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[JH1]…based on the Abstract

[JH2]Note the period.

[JH3]Once you revert to just “VFQ” from “NEI-VFQ 25” within the abstract, main body or conclusion, consistently use that shorter form within the abstract, main body or conclusion.

[JH4]OR: “Functional Acuity Score (FAS)”--??

[JH5]*If you use only the abbreviation here, you should probably use only abbreviations in all of the cases here (FVS, RP)—OR, use abbreviations in NONE of the cases here.

[JH6]ok

[JH7]Unnecessary: redundant (already stated)

[JH8]background?

[JH9]See Comment 3, above.

[JH10]implicit

[JH11]Unnecessary: implicit

[JH12]Unnecessary: implicit

[JH13](makes a smoother transition from previous sentence/paragraph to this one)

[JH14]Unnecessary

[JH15]OR (alternative meaning): “varied in gender and age” / “varied in gender, age and form of RP”