Translation and validation of a Filipino version of the glaucoma ...

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depending on the patients’ comments and the SGD analysis.The SGD also determined whether or not a Filipinoquestionnaire was necessary based on the difference ofthe patient’s scores (or lack thereof) in the English vs.the Filipino questionnaire and on the understanding andpreferences of the patients. The SGD came up with thefinal Filipino Glaucoma Quality of Life Questionnaire.Validation of questionnaire as a glaucoma-screening toolTime-based sampling was used to select the patients tobe screened during the testing period (patients who qualifiedfor either group, whether the glaucoma group or thecontrol group, who came in during a one-week periodat the clinics.) The patients underwent a comprehensiveinterview and ophthalmologic examination. A researcherassociate administered the questionnaire to the patientsthrough an interview. Any comments from the patientsregarding the questionnaires and mode of administrationwere noted.The glaucoma patients were divided into two subgroups:those with primarily visual field defects (glaucomatous-visual-fieldgroup or GVF) and those with large glaucomatousdisc-photoor GDF. The mean scores of each subgroupwere computed and compared with those of the normalgroup using independent t-test. The level of significancewas set at p = 0.05.RESULTSSelection of questionnaireThe SF–36, NEI VFQ–25, and the GQL–15 wereconsidered for use in the study. Studies assessing thedifferent quality-of-life questionnaires showed that theGQL–15 has good correlation with the clinical indices ofglaucoma. 3-6 It was, therefore, selected for translation.Translation procedureThe research group discussed the results of thetranslation process, paying attention to the similarity ordissimilarity of the forward translation to the originalGQL–15. The main discrepancy between the two involvedthe grading of the severity of difficulty.The original choices in theGQL 150 – do not perform for nonvisualreasonsThe forward translation’s choices0 – does not involve vision toperform task.1 – none 1 – no difficulty2 – a little bit 2 – some degree of difficulty3 – some 3 – frequently experiencing difficulty4 – quite a lot 4 – difficult to perform task due toblurred vision5 – severe 5 – cannot perform task due to novisionThe first two (1 and 2) were similar to the original versionsbut not the last four. The discrepancy was traced tothe forward translation. The back translation was similarto the forward translation in terms of the different possibleanswers regarding severity of difficulty. However, itwas the forward translation that was noted to be significantlydissimilar to the original, with the item “3 – some”being translated into “3 – madalas,” “4 – quite a lot” beingtranslated into “4 – hirap nang makakita,” and “5 – severe”being translated into “5 – wala nang makita.” It was agreedupon by the research group that the forward translationneeded to be rectified, with the final forward translationof the different answers for severity being “1 – kung angsagot ay hindi, 2 – kung medyo nahihirapan nang kaunti,3 – kung medyo madalas mahirapan, 4 – kung may malakinghirap, and 5 – kung may matinding hirap.” The vernaculartranslation was made more faithful with regard to quantification.Most of the 15 items that represented daily activitieswere deemed to have been adequately translated. Item 2,originally “walking after dark” was eventually back-translatedinto “walking in dark alleys.” The forward translationwas similar to the original text, and it was agreed uponthat the problem was with the forward translation andnot the backward translation. Item 3, originally “seeing atnight” was eventually translated into “finding objects inthe dark.” The backward translation was deemed responsiblefor the discrepancy, having translated the originalitem into “pagtingin-tingin o paghahanap ng bagay sa dilim.”This item was agreed upon to be translated to Filipinoas “pagkita sa gabi,” in the final forward translation. Item9, originally “seeing objects coming from the side” wastranslated in the back translation into “looking at objectsaround you.” The forward translation was deemed to beadequate. The discrepancy was agreed upon to be in theback translation and thus the original forward translation“nakikita ang bagay sa paligid” was maintained. Item 13,originally “judging distance of foot to step/curb” waseventually translated into “depth perception in stepping”in the back translation. The forward translation,“pagtantya ng distansya ng paa papunta sa bangketa” wasdeemed to be adequate, and the problem was with thebackward translation and so the original forward translationwas maintained.A final forward translation was agreed upon. The differenttranslations are in the appendix.PretestingThe final forward translation was used in a pretest: 5glaucoma and 4 normal patients were interviewed. Thepatients with glaucoma had educational attainmentranging from grade school to college undergraduate.The patients’ self-rating on English proficiency averaged64 Philipp J Ophthalmol Vol. 36 No. 2 July – December 2011Philippine Academy of Ophthalmology
4.6, with the lowest score 2, and the highest score 8. Thepatients’ self-rating on Filipino proficiency averaged9, with the lowest score 7 and the highest score 10 (3patients). There was a difference in the average scores ofthe English and Filipino questionnaires of 4.4, the lowest2 and the highest 8. The absolute value of the differenceof the scores per item was also totaled, with an averageof 15. The biggest absolute value difference between thetwo scores was 31. There were also scores with small differencesof between 2 and 9.The control population had educational attainmentranging from grade school to high school. They had anaverage rating for English proficiency of 6.25 with thehighest score 8 and the lowest 5. They had an averageFilipino proficiency of 9, with the lowest 8 and the highest10. The average difference in scores was 7.25. The averagedifference in the absolute values of the differences inscores per item was 7.75.All in all, 6 out of 9 patients had a self-proficiencyrating in English at least 5 points lower than in Filipino.Three of these patients were responsible for the scoresthat had a large difference in the sum of absolute valuesof differences in scores per item. The average self-ratingwas 5.3/10 in English proficiency and 9/10 Filipinoproficiency. Seven out of /9 commented that they foundthe Filipino questionnaire easier to understand andanswer compared to the English questionnaire, with therest commenting the opposite. None of the respondentsfound the need for additional questions.Small-group discussionThe results of the pretest were discussed by the researchgroup along with an expert. It was deemed that althoughnot all participants had a large difference in the scoresobtained from using the English vs. the Filipino questionnaire,the presence of individuals with large differencesof answers of the English vs. the Filipino questionnairewas enough reason to have a Filipino questionnaire. Thiswas validated by the preference of all but 2 patients toanswer the Filipino questionnaire. Based on the results ofthe pretest, none of the items in the translated questionnairewere modified and no items were added. It was aagreed upon that there was enough reason warrant theneed for the use of a Filipino version of the GQL–15, andthat the final forward translation of the questionnairecould be used as is.ValidationThe final forward translation was administered topatients fulfilling the inclusion criteria. Time-basedsampling (1 week or 5 clinic days) was used. A total of13 patients with glaucomatous-visual-field findings and 8patients with glaucomatous-disc-photo findings qualifiedfor the study. The scores of patients with glaucomatousvisual fields ranged from 16 to 64, with an average of34.15/75. The scores of patients with glaucomatous-discphotofindings ranged from 23 to 62, with an average of34.5/75 (Table 1). The final forward translation was alsoadministered to normal population composed of 16 patients.Their scores ranged from 15 to 21, with an averagescore of 16.81 (Table 1).The average score of the group with glaucomatousvisual-fieldfindings was compared to the average scoreof the control group using an independent t-test. Thenull hypotheses were there was no significant differencebetween the groups with glaucoma and the normal/control group. The computed t-value of the group withglaucomatous visual fields was 2.66. The computed t-valueof the group with glaucomatous disc photos was 2.54.With a p value of 0.05, it was noted that the t values of theglaucomatous visual field group and the glaucomatousoptic disc group were higher than the t-values for theirrespective degrees of freedom based on sample size. Bothnull hypotheses were rejected and the alternative hypotheseswere accepted. There was a significant differencebetween the group with glaucomatous visual fields andthe normal/control group. There was also a significantdifference between the group with glaucomatous discphotos and the normal/control group.DISCUSSIONThe GQL–15 was chosen since it was shown to havegood correlation with clinical indices of glaucoma. Itshould be noted that the GQL–15 is just a vision-relatedquality-of-life questionnaire. The other vision-relatedquality-of-life questionnaires were not disease-specific.The GQL–15 includes questions on central and nearvision (questions 1, 14 and 15), peripheral vision (questions8, 9, 11, 12), dark adaptation and glare (questions2, 3, 5, 6 and 7), personal care (14) and outdoor mobility(questions 4, 10 and 13).The translation procedure was straightforward, withthe two translators producing the required output. Itwas noted during evaluation of the translations that themost difficult part for both translators was translating thescale of the answers to the questionnaire, as described inthe results. The research group carefully reconciled thedifferences between the two translations and comparedthem to the original questionnaire to produce the finaltranslation. The difficulty in translation was attributed tothe lack of a definite translation in Filipino of the Englishscale used in the original GQL–15 Questionnaire. Therest of the discrepancies as discussed in the results wereagreed upon to be minor differences, with the discrepanciesrectified in the final forward translation.The results of the pretest convinced the membersPhilippine Academy of Ophthalmology Philipp J Ophthalmol Vol. 36 No. 2 July – December 201165
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Page 6: Table 1.Validation ScoresGlaucoma A

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