Childhood blindness: a new form for recording causes of visual loss in children.

Update/Le point Childhood blindness: a new form for recording causes of visual loss in children* C. Gilbert,1 A. Foster,' A.-D. Negrel,2 & B. Thylefors2 The new standardized form for recording the causes of visual loss in children is accompanied by coding instructions and by a database for statistical analysis. The aim is to record the causes of child- hood visual loss, with an emphasis on preventable and treatable causes, so that appropriate control measures can be planned. With this standardized methodology, it will be possible to monitor the changing patterns of childhood blindness over a period of time in response to changes in health care services, specific interventions, and socioeconomic development. Introduction A standard classification for reporting the categories of visual loss was developed in 1975 and has been widely used to facilitate the comparison of data from different locations (1). The World Health Organiza- tion's Programme for the Prevention of Blindness (WHO/PBL) has also developed a standard protocol for reporting the causes of visual loss.a In May 1990 a global meeting on the Prevention of Childhood Blindness, convened by WHO at the Intemational Centre for Eye Health (ICEH) in London, recommended that further information was required on the prevalence, incidence and causes of visual loss in children because few data were currently available (2). The results from population- based studies indicate a lower prevalence of blind- ness in children than in adults, ranging from approxi- mately 0.2-0.3 per 1000 children in industrialized * A French translation of this article will appear in a later issue of the Bulletin. I Department of Preventive Ophthalmology, Institute of Ophthal- mology, London, England. 2 Programme for the Prevention of Blindness, World Health Organization, 1211 Geneva 27, Switzerland. Requests for reprints should be sent to this address. a WHO/PBL Eye Examination Record (unpublished document WHO/PBUEER 111/1988) and Coding Instructions for the WHO/PBL Eye Examination Record (Version I11) (unpublished WHO document PBU88.1). Geneva, World Health Organization, 1988. Reprint No. 5406 countries to approximately 1.0-1.5 per 1000 children in very poor communities (3). The available informa- tion on the causes of visual loss in childhood shows marked regional variations; corneal scarring second- ary to vitamin A deficiency, measles infection or ophthalmia neonatorum is the main cause of child- hood blindness in Africa and Asia, while retinal dis- ease and lesions of the central nervous system are more important causes in Europe and North America (4). Difficulties in comparing the causes of visual loss in children are due to lack of a standardized reporting system which takes into account both ana- tomical and etiological classifications. In an effort to overcome this problem, the ICEH in London, which is a WHO Collaborating Centre for Blindness Pre- vention, in collaboration with WHO, has now devel- oped a standardized protocol (the WHO/PBL Eye Examination Record for Children with Blindness and Low Vision) for reporting the causes of visual loss in children. The form is accompanied by a set of coding instructions and a database for analysis. The new form The object of the record is: - to identify preventable and treatable causes of childhood visual loss so that appropriate control measures can be planned; - to provide a mechanism for monitoring changing patterns of childhood blindness over a period of time in response to changes in health care ser- Bulletin of the World Health Organization, 71 (5): 485-489 (1993) © World Health Organization 1993 485 C. Gilbert et al. vices, specific interventions, and socioeconomic development; - to assess the requirements of individual children for medical and/or surgical treatment, optical correction and low vision services; and - to assess the educational needs of visually dis- abled children so that appropriate education ser- vices can be planned. The form is primarily designed to record the causes of blindness and low vision in children in schools for the blind and those attending hospital clinics. It can also be used to document the causes of visual disability in children identified during popula- tion-based prevalence surveys. The form is not designed for collecting information on the preva- lence of eye disease in children (e.g., trachoma, xerophthalmia). The form also has sections for recording demographic data, the presence of addi- tional disabilities, and information relating to the child's education. Coding instructions It is recommended that, if at all possible, a team of trained personnel should undertake the assessments, each one completing the relevant sections of the form. Ideally, the team should consist of an ophthal- mologist, an optometrist or optician, a specialist with expertise in this field of education, and ancillary staff with local knowledge and experience in visual acuity and visual field assessments. The form consists of 13 sections (Fig. 1). It is recommended that sections Al or A2, and B, C and D should be completed by ancillary staff trained for the purpose; sections E, F, H, I, J, K, L and M by an ophthalmologist; section G by an optometrist or opti- cian; and section K by an educationalist. All sections should be completed for every child. If this is not possible, specific sections should be used or omitted consistently throughout any one study. The coding instructions, which accompany the form, are to be used in preparing ophthalmologists and other members of the assessment team in the use of the form prior to data collection, as well as serv- ing as a reference. The coding instructions include methods of assessing vision, definitions of condi- tions, and guidelines on completing the different sec- tions of the form. Contents Sections Al and A2. Census. Section Al is to be completed for children in schools for the blind and hospital clinics, and section A2 for children with visual loss identified during population-based preva- lence surveys. Section B. Personal details. This section records demographic data, the age of onset of visual loss, the presence of a positive family history, and whether there is a history of consanguinity. Section C. Visual assessment. Section C is used to record visual acuity measurement (classified accord- ing to the WHO Intemational Classification of Dis- eases, categories of visual loss) and a simple assess- ment of functional vision and visual fields. Section D. General assessment. This section has been included for the identification of other disabil- ities which may assist in determining the etiology of visual loss or the educational requirements of the child. The definitions of disability given in the coding instructions are those of the Intemational Classification of Impairments, Disability and Handi- caps (5). Section E. Previous eye surgery. This section is to be completed after consulting medical records, obtaining a history from adults with knowledge of the child's past medical history, and performing a clinical examination of the child. Section F. Eye examination: site of abnormality leading to visual loss. The purpose of this section is to identify the sites of abnormality leading to visual loss (i.e., the anatomical site causing visual loss) for each eye, and then for the child. Details of defini- tions are given in the coding instructions. If an eye has more than one abnormality, only one site should be selected as the major site for that eye, using the guidelines given in the coding instruc- tions, which place emphasis on preventable and treatable conditions. Whether the major sites of abnormality are the same or different between the right eye and the left eye, only one is selected as the abnormality for the child, again using the criteria given in the coding instructions. Section G. Refraction/low vision aid assessment. This section should be completed if examination of the eye suggests that refraction may improve the vis- ual acuity. The decision to perform refraction should not be based solely on improvement in acuity with pinhole testing. The best corrected visual acuity is recorded and the corrective lenses specified. If the child already uses low vision aids for near or distance, or is assessed for low vision aids, the visual acuity using the optical aid is recorded. Section H. Eye examination: etiology of visual loss. The purpose of this section is to record the disease or other conditions causing visual loss, which are cat- egorized according to the time of onset of the con- WHO Bulletin OMS. Vol 71 1993486 A new form for recording childhood blindness Fig. 1. Recto side of the new form; the verso side Is on the next page. The normal size is A4. WHO/PBL EYE EXAMINATION RECORD FOR CHILDREN WITH BLINDNESS AND LOW VISION A.1 CENSUS BLIND SCHOOL / HOSPITAL STUDIES E. PREVIOUS EYE SURGERY Tick all that applyCountry No.[]jj] School/Hopital No.] Child No. ] Right Left(1-3) (4-5) (6-8) None (37)n (38)0 School/ Hospital Glaucoma (39)U (40)U _ ____________________ _ Cataract (41)0 (42)0 OR Comeal Graft (43)0 (44) A.2 CENSUS POPULATION BASED SURVEYS Optical Iridectomy (45)0 (46)U Removed (47)0 (48)0 Country No. Cluster No. Surgery, type unknown (49)0 (50)0 (1-3) (4-6) Other, (51)0 (52)0 Household No. L Child No. L Scify (7-9) (10-11) Please give full details including dates, if available, B. PERSONAL DETAILS OF CHILD Right eye ------------ Left eye ____ Name:- _ ---------------- Home Town\Village: -____ ____________ ---------------- Ethnic Group: ------------------------ Age: E In months (0-1 yr olds) Sex: ]Mabl = 1 F. EYE EXAMINATION - Site d ABNORMALITY leadirg to VISUAL LOSS (12-13) (16) Female = 2 For each eye mark one majorab[moalj)y [In I _ds and all othe that contribute to visualloss141nyears(1-yr o) Right Eye Left Eye Age at onset of visual loss: Family history: Major Others Major Others 00 Since birth Is there a family history of Whoie globe: (53) °(9)LIII ~~~~~thesame condition? Ptii (4 (0 01-15 in Yearm Anophthalmos 2 0 (55) 0 2 0 (91) 99 Unknown 30 Unknown Microphthalrnos 0 3 0 (56) 0 3 0 (92) (19) Buphthalmos 0] 4 Os(7) 0 4 0 (93) If yes, who is sirnrlarly affected? Glaucoffma 0 5 0 (58) 0 5 0 (94) .________________ Removed 0 ° (59) 0 e 0 (95) Disorganised '7 0 (60) 0 7 0(96)Consanguinity: 1 Yes Other 0 a 0 (61) 0 a 0 (97) Is there a history of consanguinity? 20 No 3 Unknown Comea:(20) Staphyloma 0 9 0 (62) 0 9 0 (98) Scar lo 0(63) 010 0(99) C. VISUAL ASSESSMENT Keratoconus 0 II 0 (64) 0 II 0(1oo) 1) Distance vision: With presentglasses Qi Dystrophy 012 0 (65) 0 12 0(101) Unaided 02 Other Opacity 0 13 0 (66) 0 13 0(102) (21) Test each eye separately, then together. Lens: Right Left Rlght Cataract 014 0(67) 0 14 01(103) 6/6-6/180 1 0 ~~~~~~~~~~~~~aft~~Aphaida 0 15 0(68) 0 15 0(104)lesthan6/18-660 2 0 0tet Other is 0 (69) | is 0(105) less than 6/60 - 3/60 0 3 0 0 Uvealess than 3/60 - PL 0 4 00 AUv irsda a 17 ° (70) 017 :(106)No light perception 0 5 0 0 Ankrldia 0 17 0 (70) 0 17 0(106) Cannot be tested Uveitis 019 0 (72) 0 1 0o(107)believed sighted 0 0 Other 0 20 0 (73) 0 20 0(109) (22) (23) (24) Retina: 2) Functional vision: Test with both eyes together Yes Nio lotTested Dystrophy 0 21 0 (74) 0 21 0(110) Canseetowalkaround (25)0 1 02 0 3 Albinism 0 2 O(75) 0 22 0(111) Can recognisefaces (26)0 0 0 ROP 0 23 0 (76) 023 0(112)Cansee print (27)0 0 0 Retihober oma 0 24 0 (7) 0 24 0(113) Believed useful residual (28)0 0 Other 25 0 p8) 0 25 0(114) s Felds Test each eye separately Ootic Nerve: 0 0(79) 0(116) RightLeft ~~~~~~~~~~Hpolai 0 27 0 (60) Q 27 0 (116) Full field 0 ' 0 Oter 28 ° (81) 0 280(117) Hemianopia 0 2 0 Constricted to less than 10° 3 0 O02er,notlisted 029 O (82) 029 0(l18)Other field loss 0 40 OhrntIse 9) Q9 016 Cannot test 0 00 Globe appears normal ( complete after refraction see Section G)Not tested 03 6 0 Specifytypeoftest (29) (30) Refractiveerror 030 0 (83) 030 0(119) _______________ -------------- Amblyopia 0 31 0 (84) 031 0(120) Cortical blindness 0 32 0 (85) 0 32 0(121) D. GENERAL ASSESSMENT Idiopathic nystagmus 0 33 0 (86) 0 33 0(122) Additional disability Tick all that apply Normal vision 0 34 (67) 0 34 0(123) None (31) Q Not examined 0 99 (88a) 99 (88b) Hearing loss (32) U Mental retardation (33) 0 Physical handicap (34) U THE MAJOR SITE OF ABNORMALITY LEADING TO VISUAL LOSS Epilepsy (35) 0 FOR THE CHILD (124)Other (36) EY 0 RightSpecify SELECT RIGHT ORLEFT E 0 Left WHOBul__etin___M___Vol__711993_4__ WHO Bulletin OMS. Vol 71 1993 487 C. Gilbert et al. r. RFFRACTION /I W VISION AIn ASSFSMFNTI No Yes No indicated Vision improves with a pinhole 1 0(125)02 0 3 Refraction performed now 1 0(126)02 Vision assessed with low vision aid 1 0(127)02 0 3 1 If refraction oerformed. visual acuity with corrective lenses: Not done 04 Distance: Test each eye separately, then together RightRight Left & Left 6/5 - 6/18 0 ' 0 0 less than 6/18 - 6/60 0 2 0 0 less than 6/60 - 3/60 0 3 0 0 less than 3/60 (08 4 0 0 Specify corrective lenses and visual acuity Right eye - VA ._._ _ Left eye - --- -.-.-.-_ VA.__. Near: Test with both eyes together Can discem print /symbols equal to Yes No or smaller than Smm (<5mm) (131)01 0 2 El0A Example of 5mm symbols 2) If assessed with low vision aid (LVA). visual acuity with LVA Distance: Specdfy type of LVA and visual acuity Right eye - -VA._._ Left eye VA ...... Near: Specify type of LVA and near acuity Right eye . _ VA_ Left eye -VA.__. Right Left Can discem print< 5rnm 0 1 0 Candiscem print>5mm 0 2 0 Cannot discem print 0 3 0 (132) (133) H. EYE EXAMINATION - AETIOLOGY OF VISUAL LOSS 2) Intrauterine Rubella (146) 0 1 0 2 147)0 1 Q 2 factor: Toxoplasmosis (148) 0 0 149)0 0 Drugs / alcohol (150)0 0 151)0 0 Other, (152) 0 0 153)0 0 Specify 3) Perinatal/ Cerebral hypoxia Anjury (154)0 1 0 2 155)0 1 0 2 Neonatal R.O.P. (156)0 0 157)Q 0factor: Ophthalmia neonatorum(158)0 0 159)Q 0 Other (160)0 0 161)0 0 Specify 4) Postnatal/ Vitamin A deficiency (162)0 1 0 2 (163)0 1 0 2 Infancy/ Measles (164) 0 (165)0 0Childhood Neoplasm (166)H 0 (167)0 Ofactor Truma (168)0 0 (169)0 0 Harmful Trad. Practices (170)0 0 (171)0 0 Other (172)0 0 (173)0 0 Specify 5) Cannot Cataract (174) 0 (175) 0determine Glaucoma / Buphthalmos (176) 0 (177) 0(unknown Retinoblastoma, no FH (178) 0 (179) 0 aetiology)) Abnormality since birth (180) 0 (181) 0 Specify Other (182)[3 (183) 0 Specity.. THE MAIN AETIOLOGY OF VISUAL LOSS FOR THI=CrHIL SELECT ONE FROM POSITIONS 134-183 I___J (184) J. PROGNOSIS FOR VISION Tick one box only for each eye Right eye Left eye Could be improved 0 1 0 1 Ukely to remain stable 0 2 0 2 Ukely to deteriorate 0 3 0 3 (193) (194) M. EXAMINER: Examined by (month) (vear) Date 1197-200M mm0 5 10 15 20 25 30 WHO Bulletin OMS. Vol 71 1993 I. ACTION NEEDED 1 ) ODtical Tick all that apply None (185) 0 Refraction later (186) 0 Spectacles (187) 0 Lowvision aid (188) 0 2) Medical / Surgical Tick all that apply None (189) 0 Medication (190) 0 Surgery (191) 0 Specfy. Other (192) 0 Speciy___________________________ K. EDUCATION 1) Present schoolinq Tick one box only Special school for the blind 0 1 Special school for the multiply handicapped 0 2 Integrated education 0 3 None 0 4 Other 0 5 Specify (195) ____________________________ 2) Recommendations: YES NO Change in schooling recommended (196) 0 Specify Select one of the categories 1-5 for each eye Tick all that apply within the selected category. Right eye Left eye Dusite Suspect Deinite Suspect 1)Hereditary Chromosomal (134)01 02 (135)0 1 02 Disease: Mitochondrial (136)0 0 (137)0 0 Autosomal dominant (138) (139)O 0 Autosomal recessive (140)0 0 (141)0 X-Iinked (142)0 0 (143)0 0 Cannot Specify (1la) 0 (145) 0 L FULL DIAGNOSIS Specify full anatomical and aetiological diagnosis: Right eye: Left eye: 488 A new form for recording childhood blindness dition. Based on the major anatomical site of visual loss (reported in section F), the etiology is recorded for each eye and then for the child. If these differ between the right eye and the left eye, the etiology of visual loss for the child should be that of the major anatomical disorder for the child (recorded at the end of section F). The category "Cannot determine, unknown eti- ology" is filled in when the underlying etiology is not known. This includes conditions present since birth and those that cannot be specifically attributed to genetic or intrauterine factors. Section 1. Action needed. The examination having been completed, this section records whether optical, surgical or medical intervention is required. The type of surgery should be specified. Section J. Prognosis for vision. This section records the likely prognosis for vision. Section K. Education. The type of education the child is currently receiving is recorded, and whether a change in schooling or other assessment is recom- mended. Section L. Full diagnosis. The full diagnosis is recorded with as many details as possible. Section M. Examiner. This section gives the names of the examiners. Database A database has been created to accompany the form; it includes the facility for standardized statistical analysis of data by anatomical disorder, etiological category, age group and sex. The database has been designed so that it can be used by those with little experience of computerized data management. A centralized data bank will be kept at ICEH in London, and in WHO in Geneva. Pilot studies and experience The form has been reviewed by ophthalmologists with a special interest in paediatric ophthalmology, and modified during the course of examining approximately 1600 children in schools for the blind in four different continents over an 18-month period. During the pilot studies, children were examined by local opthalmologists as well as by those involved with developing the form. The findings of some of these studies have been published (6, 7). The form has so many details that an initial short period of instruction is usually required for those not fam- iliar with paediatric ophthalmology. With a team of trained personnel, it is possible to examine and com- plete the form on 5-8 children/hour in schools for the blind. Discussion The new form, which is focused on children with blindness and low vision, is more detailed than the comparable form in general use for all age groups,b and reflects the more varied causes of visual loss in children. The majority of the sections in the form have to be completed by an ophthalmologist because it was not designed to be used by trained field workers or paramedical staff. The prevalence of childhood blindness is less than that of adult blind- ness, and the numbers in any one study are likely to be small. Additional sections have been included in the new form so that requirements for educational and optical services can also be evaluated. The form and coding instructions have been translated into French and Spanish, and copies with the coding instructions and database are available from the Intemational Centre for Eye Health, London, and the WHO Programme for the Preven- tion of Blindness, Geneva. b See footnote a on page 485. Acknowledgement The valuable support provided for this work by Christoffel Blindenmission, Sight Savers, and the Oxford Ophthal- mological Congress Award is gratefully acknowledged. References 1. Guidelines for programmes for the prevention of blindness. Geneva, World Health Organization, 1979, p. 16. 2. Prevention of childhood blindness. Geneva, World Health Organization, 1992. 3. Foster, A. & Gilbert, C. Epidemiology of childhood blindness. Eye, 6: 173-176 (1992). 4. Foster, A. Childhood blindness. Eye, 2 (suppl.): S27- S36 (1988). 5. International classification of impairments, disabil- ities and handicaps. A manual of classification relat- ing to the consequences of disease. Geneva, World Health Organization, 1980. 6. Gilbert, C. et al. Causes of childhood blindness: results from West Africa, South India and Chile. Eye, 7: 184-188 (1993). 7. Gilbert, C. & Foster, A. Causes of childhood blind- ness in Thailand and the Philippines. International ophthalmology (in press). WHO Bulletin OMS. Vol 71 1993 489