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TAMIZAJE PARA DEFECTOS REFRACTIVOS EN ESCOLARES. Dr. Van Charles Lansingh. DETECCIÓN DE CASOS. “ENFERMEDAD” ASINTOMÁTICA CUANDO EL PACIENTE ACUDE A USTED. TAMIZAJE. YOU GO TO THE PEOPLE. YOU TEST FOR A “ASYMPTOMATIC DISEASE”. SCREENING REQUIREMENTS. 1. IMPORTANT DISEASE 2. EASY,
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TAMIZAJE PARA DEFECTOS REFRACTIVOS EN ESCOLARES Dr. Van Charles Lansingh
DETECCIÓN DE CASOS “ENFERMEDAD” ASINTOMÁTICA CUANDO EL PACIENTE ACUDE A USTED
TAMIZAJE YOU GO TO THE PEOPLE. YOU TEST FOR A “ASYMPTOMATIC DISEASE”
SCREENING REQUIREMENTS 1. IMPORTANT DISEASE 2. EASY, “ACCURATE”, TEST INEXPENSIVE 3. EFFECTIVE } AVAILABLE } TREATMENT AFFORDABLE}
SENSITIVITY SENSITIVITY = TRUE POSITIVE ALL DISEASE
SENSITIVITY SENSITIVITY = TRUE POSITIVE ALL DISEASE IF SENSITIVITY IS HIGH THEN YOU FIND MOST OF THE CASES. IF IT IS LOW THEN YOU MISS CASES.
POSITIVE PREDICTIVE VALUE POS PRED VAL = TRUE POSITIVE / ALL POSITIVE
POS PRED VALUE PPV = TRUE POSITIVE ALL POSITIVE IF PPV IS HIGH THEN MOST OF THE CASES REFERRED NEED TREATMENT. IF IT IS LOW THEN MOST OF THE REFERRED CASES DO NOT NEED TREATMENT - WASTE OF TIME.
SCREENING 1 For what disease are we screening ? 2 What test is available? 3 What treatment can we provide?
SCREENING Diseases Test Treatment Glaucoma Diab Ret Ref Errors Amblyopia Strabismus
SCHOOL SCREENING POSSIBLE DISEASES All refractive errors Significant refractive errors defined as : “most children will wear the spectacles”
REF MILD MODE SEVERE ERROR RATE MYOPIA 0.25 - 1.00 - 3.00 0.75 2.75 HYPER 0.25 - 3.00 - 5.00 2.75 4.75 ASTIG 0.25 - 1.00 - 3.00 0.75 2.75 DEFINITIONS
REF MILD MODE SEVERE ERROR RATE MYOPIA 0.25 - 1.00 - 3.00 0.75 2.75 HYPER 0.25 - 3.00 - 5.00 2.75 4.75 ASTIG 0.25 - 1.00 - 3.00 0.75 2.75 DEFINITIONS NO SPECS SPECS SPECS
SCHOOL SCREENING Significant Refractive errors Myopia of 1D or more Astigmatism of 1D or more Hyperopia of 3D or more All these are both eyes !
SCHOOL SCREENING Significant Refractive errors Myopia 1D 2.0% Astigmatism 1D 0.5% Hyperopia 3D 0.1% All these are both eyes !
SENSITIVITY AND PPV VA SENS. PPV <20/30 UN1 100 12 <20/30 BI 100 16 <20/40 UNI 98 45 <20/40 B1 91 71 <20/60 UNI 73 66 <20/60 BI 52 87
Examine children to find those who need and will wear spectacles 1. TEST CHILDREN TO FIND “ NORMAL” AND “ABNORMAL” 2. EXAMINE ABNORMAL FOR SPECTACLES, REFRACTION. 3. PROVIDE SPECTACLES AT AN AFFORDABLE COST 4. FOLLOW UP TO CHECK THAT SPECTACLES ARE WORN, AND POWER ADJUSTED 5. ONGOING PROGRAMME FOR ALL
PROGRAMME 1. SIGNIFICANT REFRACTIVE ERROR NEEDING SPECS IN CHILDREN 6 YRS + 2. TEST 20/40 BE See Cannot See “Normal” “Abnormal”
PROGRAMME 3. REFRACT ABNORMALS and PROVIDE SPECTACLES 4 IS IT WORTHWHILE?
PROGRAMME 1. FOR 1 MILLION POPULATION THERE ARE ABOUT 25,000 CHILDREN AGED 6 YEARS, AND 25,000 AGED 12 YEARS . A TOTAL OF 50,000. 2. IF 300 CHILDREN ARE EXAMINED PER DAY THEN ALL CHILDREN CAN BE EXAMINED IN 30-35 WEEKS. 3. APPROX. 1-5% WILL NEED SPECTACLES, THAT IS 500 -2500 SPECS / YEAR / MIL. POP.