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

Glaucoma causes characteristic visual-field lossand optic neuropathy. If severe enough, it can lead tosignificant visual disability 1-2 and affect quality of life.A patient’s ability to enjoy normal life activities can becompromised. This can be assessed through specific validatedtools, such as the different health-related qualityof-lifequestionnaires (HRQoL). The use of a HRQoLallows the patient’s perspective to be included in themethodological framework of evidence-based medicine.These questionnaires have shown usefulness in assessingvarious life-threatening, progressive, or chronic illnesses,such as glaucoma. 3Some of these quality-of-life assessment tools havebeen used to assess the quality of life of glaucoma patients.Several of the questionnaires are not disease-statespecific, such as the Medical Outcomes Study Short Form36 (SF-36) and the Sickness Impact Profile (SIP). SF 36is an easy-to-use questionnaire known as a multipurposemedical-health survey. Despite being considered reliable,it has not been shown to correlate well with vision-relatedailments, such as glaucoma. The SIP is considered a validand reliable tool for assessing quality of life in diseasestates, but is deemed impractical in clinical setting dueto the length of time it takes to complete the questionnaire.4Other questionnaires are vision specific, but not necessarilyspecific for glaucoma. Examples are the VisualFunction Index-14 (VF-14), the National Eye InstituteVisual Function Questionnaire (NEI-VFQ), and the NEI-VFQ 25. The VF-14 was originally developed to assessquality of life of cataract patients and has only moderaterelevance to assessing impact of visual acuity on qualityof life among glaucoma patients. Since it failed to takeinto consideration the effects of visual field and colorvision defects, two important indicators of optic-nervedamage, it has proved inadequate in measuring qualityof life in glaucoma. The NEI-VFQ, a well-validated tool inassessing vision-dependent tasks, is more sensitive thanthe SF-36 in differentiating patients with glaucoma, but isdifficult to use. The NEI-VFQ 25 is an improved versionof the NEI-VFQ. Despite being easy to use, well validated,and reliable, its lack of emphasis on visual-field effect onquality of life has lessened its test value in glaucoma. Inspite of its shortcomings, it is one of the more widely used(and translated) visual-field-function questionnaires.Along with the NEI-VFQ, it has become the benchmarkfor quality-of-life questionnaires specific to glaucoma. 4There have been various attempts in the past decadeto create a glaucoma-specific HRQoL. Rouland and colleaguesof the Hôpital Claude Huriez in Lille, France,noted a lack of HRQoLs for ophthalmologists. Theycreated the first glaucoma-specific quality of life scaleto provide researchers and physicians a comprehensive,practical, and validated tool for assessing patients withglaucoma. 3The Glaucoma Quality-of-Life Questionnaire (GQL15) was designed by Nelson and colleagues in 2003. 5 Theyattempted “to explore patients self-reported visual disabilityresulting from glaucoma by means of a questionnairedeveloped for this purpose; identify activities stronglyassociated with a measure of visual-field loss; quantify differentpsychophysical aspects of visual function; and assessthe relationship between objective measures of visualfunction and patients’ perception of their vision-relatedquality of life.” Of the 50 questions used in the study, 15were noted to have a strong and significant relationshipwith a measure of visual-field loss, which comprise nowthe GQL 15. The perceived visual disability relating todark adaptation, disability glare, activities demandingfunctional peripheral vision was highly associated withthe severity of binocular visual-field loss. The GQL 15was developed to include 5 key activity groups in dailyliving, namely central and near vision, peripheral vision,dark adaptation and glare, personal care, and outdoormobility.The GQL 15 has been used in various studies. Goldbergand associates used the GQL 15 to quantify difficulty inthe performance of daily activities in patients with openangleglaucoma (OAG). They demonstrated that patientswith OAG had a significant deterioration in quality oflife which correlated strongly with reduced visual acuity,severity of visual-field defects, and presence of binocularfield defects. 6Country-specific quality-of-life questionnaires werealso developed. Toit and colleagues developed and validateda vision-specific quality-of-life questionnaire of EastTimorese. 7 Krochik et al. translated the National EyeInstitute Visual Function Questionnaires into Spanish inBuenos Aires, Argentina. 8Currently, there is no validated Filipino glaucomaquality of life questionnaire. This study aimed to developand validate a vision- and language- or vernacular-specificGQL–15 adapted to Filipino glaucoma patients, whichcould reveal peculiar self-proclaimed insights into thedebilitating effects of glaucoma on vision and life itself.We translated the Glaucoma Quality of Life Questionnaire15 (GQL–15) into Filipino, determined its value,and validated its usefulness among patients.METHODOLOGYAfter assessment of the different vision-specific qualityof-lifequestionnaires, the Glaucoma Quality of Life Questionnaire–15(GQL–15) was used as basis for the Filipinoquestionnaire.The translation procedure involved translation, reconciliation,pretesting, and small-group discussion based62 Philipp J Ophthalmol Vol. 36 No. 2 July – December 2011Philippine Academy of Ophthalmology

on the Kidscreen group Translation and Validation procedure.9 Modifications to the translation and validationprocedure were suggested and approved by an expert.The GQL–15 was translated into a Filipino version usingthe forward-backward-forward method. The questionnairewas first translated into Filipino by one independenttranslator (forward translation) who was a native speakerFilipino speaker, proficient in both English and Filipino,and familiar with the cultures of both the English-speakingcountries and the Philippines. The forward translation wastranslated back into English by a second translator, whohad not worked with the original GQL–15.Members of the research group with good knowledge ofEnglish and Filipino, as well as the forward translators, comparedthe backward translation with the original GQL–15.The group compared the backward translation with theoriginal GQL–15 item by item, eventually suggesting a versionfor the final forward translation. The back-translatedand original questionnaire should have been very similar.The discrepancies between the two questionnaires wereidentified and resolved. The reconciliation process wasconfirmed for certain translations and an alternativesuggestion was given to other translations which were notconfirmed. The end product was the final forward translation,which was expected to not have any conceptualdiscrepancies with the English original. The entire processof translation was documented appropriately.Additional questions specific for the Filipino way of lifewere generated as necessary by interviews with diagnosedglaucoma patients, additional literature review, and consultationwith experts in the field of glaucoma.Patients from the Sentro Oftalmoligico Jose Rizal of theUniversity of the Philippines–Philippine General Hospital(UP–PGH), diagnosed to have glaucoma, made up thestudy population. Included were patients who:• had been diagnosed with primary glaucoma, whetheropen-angle or angle-closure, and had been seen by at leastone consultant;• were more than 20 years old and can read, write, andspeak in conversational Filipino;• had best-corrected distance visual acuity of 20/40 orbetter;• had undergone at least 2 automated visual-field testssince the time of diagnosis (the perimetry tests shouldbe reliable, with less than three fixation losses and bothfalse-negative and false-positive responses less than 10%each and the tests should have been officially read by aconsultant);• were deemed to be neurologically capable of answeringthe questionnaire (i.e. those oriented to time/place/person, those with intact sensorium);• who have had at least one photo of the optic nervesofficially read by a consultant;• may or may not have undergone glaucoma-relatedsurgery (filter, valve, or laser surgery) or cataract surgery;and• had been regularly consulting (at least 4 follow-ups)at the UP–PGH Glaucoma Clinic within the past calendaryear.Excluded were patients who:• had eye diseases other than glaucoma (retinal pathologies,non-glaucomatous optic-nerve pathologies) orglaucoma secondary to an underlying eye disease;• had undergone eye surgery not directly related to theprimary glaucomatous pathology (i.e. retina surgery, penetratingkeratoplasty, panretinal photocoagulation, etc.);• were unable to read, write and converse in conversationalFilipino.A control group of patients with no known eye diseaseaffecting vision to below 20/40 for distance vision with appropriatecorrection (i.e. correctible error of refraction)was recruited from the general clinic.Patients were asked to fill up a consent form indicatingtheir willingness to participate in the study. The patients’name, age, sex, educational attainment and diagnosis werenoted.PretestingThe translated questionnaire was pretested vis-à-visthe original questionnaire to determine its functionality(whether it was too hard to understand, confusing,inadequate, or there were other issues the intervieweeswanted addressed) and whether or not there is a need fora Filipino version of the glaucoma quality-of-life questionnairein the first place. The questionnaire was intervieweradministered.The patients were asked to score themselveson a scale of 1 to 10 regarding their self-assessed proficiencyin English and Filipino. They were interviewed with bothquestionnaires (English and Filipino). The selection ofthe first questionnaire to be used was done randomly (flipof a coin). After the scores were taken, the patients wereasked regarding their comments on both questionnairesand whether they understood better and preferred thequestionnaire in Filipino or English.Small-group discussionThe pretesting results were discussed by the researchersalong with another individual familiar with the useof screening tools in the health social sciences in asmall-group discussion (SGD) to determine whether thetranslated questionnaire could be adequately understoodand answered by the patients (based on their commentsgiven during the pretesting phase). The SGD also tookinto consideration the comments of the patients regardingthe content of the questionnaire. Specific items inthe questionnaire were modified or altogether removedPhilippine Academy of Ophthalmology Philipp J Ophthalmol Vol. 36 No. 2 July – December 201163

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

Table 1.Validation ScoresGlaucoma AVFGroup28162635623527253047266423Glaucoma discphoto group2328264730253562Normal group21181718151515151515161722191516of the small group discussion that a Filipino version ofthe GQL–15 Questionnaire was needed. Out of the 9pretested individuals, 7 remarked that they had an easiertime answering the Filipino version of the questionnaire.The average of the self-rating in English proficiency ofthe pretested patients was 5.33/10 as against 9/10 inFilipino proficiency, which the researchers deemed to bea significant difference. Six out of the 9 pretested individualshad a self-rating in English proficiency 5 points(out of 10) lower than in Filipino proficiency, which thegroup also found to be significant.What was even more significant were the 3 patientswhose sum of the absolute value of the differences ofscores answered for each question in Filipino and Englishwere 23, 29 and 31, representing a large differencein the answers given when the patients were asked thesame question in English and in Filipino. These patientshad self-rating in English proficiency at least 5 pointsout of 10 lower than in Filipino proficiency. These samepatients were also part of the group which remarked thatthey had an easier time and preferred answering theFilipino questions.Subjectively, it was noted during the interview thatthese same patients had a difficult time understandingthe English questions, but had an easier time answeringthe Filipino questions. Given all these data, the group assessedthat these patients had a difficult time understandingand answering the English questionnaire. Majority ofthe respondents also preferred answering the Filipinoquestionnaire. All these data and observations showedthat the there was enough reason to produce a Filipinoversion of the GQL–15.The validation showed that the scores of the groupswith glaucoma were around double that of the normalpopulation. Based on the independent t-test, there wasa statistically significant difference between the scores ofthe glaucoma patients and the normal population, usingthe final forward translation of the GQL–15 (p = 0.05).Since, like the English version of the questionnaire, theFilipino version was able to have significantly differentscores between the two groups, the research groupdetermined that the final forward translation was a validversion of the GQL–15.In summary, the GQL–15 was successfully translatedinto Filipino.The English version of the GQL–15 will not sufficefor measuring quality of life in most Filipino patients.Filipino version of the GQL–15 is necessary to meaningfullymonitor Filipino patients with glaucoma, and seemssuperior to the English version in doing so.The final forward translation of the Filipino GlaucomaQuality of Life Questionnaire is a valid tool in assessingquality of life in patients with glaucoma.A larger population may be used in both the normaland glaucoma groups to more strongly validate theFilipino version of the questionnaire as a valid tool inassessing quality of life among glaucoma patients. Thequestionnaire may be used to determine whether thereis increasingly poorer quality of life in patients withincreasingly more severe glaucoma, with regard to bothstructure and function.References1. South East Asia Glaucoma Interest Group Asia Pacific Guidelines, SecondEdition2. American Academy of Ophthalmology Basic and Clinical Science Course,Glaucoma, 2004-2005.3. Rouland JF, Denis P, Béchetoille A, et al. Du Groupe D’étude Glaucome Et QualitéDe Vie. Creating a specific quality-of-life questionnaire in patients with glaucoma:item generation. J Fr Ophthalmol 2002; 25: 785-794.4. Severn P, Fraser S, Finch T, May C. Which quality-of-life score is best for glaucomapatients and why? BMC Ophthalmology 2008 Jan 23: http://www.biomedcentral.com/1471-2415/8/2 (accessed October 21, 2009).5. Nelson P, Aspinal P, Papasouliotis O, et al. Quality of life in glaucoma and itsrelationship with visual function. J Glaucoma 2003; 12: 139-150.6. Goldberg I, Clement CI, Chiang TH, et al. Assessing quality of life in glaucomapatients using the Glaucoma Quality of Life–15 (GQL–15) Questionnaire.J Glaucoma 2009; 18: 6-12.7. du Toit R, Palagyi A, Ramke J, et al. Development and validation of a visionspecificquality-of-life questionnaire for Timor-Leste. Invest Ophthalmol Vis Sci 2008; 49:4284-4289.8. Krochik V, Loayza Gamboa W, Saenz Valiente A, Lerner F. Quality of life inpatients with glaucoma in Buenos Aires, Argentina. Presented at ARVO MeetingApril 2011. Invest Ophthalmol Vis Sci 2008; 49: 1585.9. Kidscreen Group. Kidscreen Translation and Validation Procedure. 2004. http://www.kidscreen.org/cms/newtranslation (accessed October 21, 2009).66 Philipp J Ophthalmol Vol. 36 No. 2 July – December 2011Philippine Academy of Ophthalmology