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Childhood Hyperopia. NEIL SINCLAIR RVEEH MOTILITY JNL CLUB EDITED BY LIONEL KOWAL. Slide 1 Epidemiology. Prevalence Definition varies between studies ie some use spherical equivalent and others most hyperopic meridian. Some use cycloplegia, some not.
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Childhood Hyperopia NEIL SINCLAIR RVEEH MOTILITY JNL CLUB EDITED BY LIONEL KOWAL
Slide 1 Epidemiology • Prevalence • Definition varies between studies ie some use spherical equivalent and others most hyperopic meridian. • Some use cycloplegia, some not.
Slide 2 EpidemiologyAtkinson J et al (Cambridge infant screening program) Study 1 Children 6-9 m invited for exam (71% attended) 1096 screened • hyperopia without anisometropia 4.6%. Cycloplegic photorefraction 3.5D and hyperopia confirmed with retinoscopy Study 2 Children 7-9 m invited for exam (74% attended) 3166 screened • hyperopia without aniso 5.7% Study 3 Children 8 m invited for exam (84%attended) 5091 screened • hyperopia without aniso 4.5%. Noncycloplegic photo refraction with a criterion for hyperopic focus: accommodative lag > 1.5D
Slide 3 Epidemiology • UK: typical state of the infant eye at 8-9 m is modest hyperopia (+1.5 D) • long ‘tail’ of significant hyperopia in 5% • This refraction identifies a group at increased risk of strabismus and poor acuity by age 4.
Slide 4 Epidemiology • Other estimates of hyperopia prevalence come from smaller studies which are not population based and can over estimate the prevalence due to participation bias. • Cook et al (1951) found ≥ +3D SE hyperopia in 30% of newborns. 1000 cycloplegic refractions. • Mutti et al (2005) found +3D of hyperopia in 23.5% of 221 infants at 3m, reduced to 5.4% by 9 m • Ingram et al (2000) screened 6700 infants at 6 m, 9.2% with +3.5 of meridional hyperopia. • Ingram et al also (1979) studied 1648 infants at 1 year. 3.7% with +3.5D of meridional hyperopia.
Slide 5 Natural History and Emmetropization • Corneal curvature, lens power and position and axial length are quite variable in the newborn. • The range of refractive error is from –2 to +4 (Brown 1938). • most children are born hyperopic and become less so.
Slide 6 Natural History and Emmetropization • Mutti (2005): comparing hyperopia at 3m (23.5%) with 9m (5.4%) suggested emmetropization in 1st 12 m. • Ingram (1979) followed patients at 12m and compare the rates of hyperopia at 3.5y and found little change (10.8% vs. 11.8%) • So this process mostly occurs in the first year of life.
Slide 7 Natural History and Emmetropization • Other studies have shown that there is a split in eyes that emmetropize with those eyes with lesser degrees of hyperopia emmetropizing normally. • Mutti (2005) showed a split a 4D - patients above this level failed to emmetropize • Confirmed in smaller studies by Pennie (2001) and Dobson & Sebris (1989).
Slide 8 Natural History and Emmetropization • Wood et al (1995) showed that even though the trend is towards emmetropia there is a large amount of scatter. • Some children who are hyperopic can become worse • The scatter is so marked that that you are unable to predict how hyperopic individuals will end up
Slide 09 Risk Indicator for Hyperopia and Ethnic Variation • A Twin study by Hammond et al (2001) demonstrated a high concordance of hyperopia in monozygotic twins compared to dizygotic twins. • In a population of 34 newborns to parents/ siblings with accommodative ET, hyperopia of 4D was found in 38% of infants at 6m.
Slide 10 Risk Indicator for Hyperopia and Ethnic Variation • There is no ethnic based data on infants. The Refractive error studies in children compared refractive error in children as young as 5 • Chile 2D hyperopia in 24.5% of right eyes (myopia 3.4%) • Nepal 2D hyperopia in 1.9% of right eyes (myopia 0.4%) • Separate study Finnish 2D hyperopia 12.5%
Slide 11 Risk Indicator for Hyperopia and Ethnic Variation • Robaei et al. Recent Australian paper gave prevalence of 4.6% in whites and 2.4% in non whites • Cleere (refractive error and ethnicity in children) demonstrated racial differences in rates of hyperopia (1.25D) in children from 5 to 17 years of age. Whites 19.3%, Hispanics 12.7% Asians and blacks 7%.
Slide 12 Risk Indicator for accommodative ET • Ingram et al • 285 patients at 6m with 4D of hyperopia followed for 3.5 years • 24% became esotropic • patients at 12m with 3.5D of hyperopia • 45% became esotropic • Atkinson et al • 124 patients at 6-8, with 3.5D hyperopia • 15% became esotropic • 1.6% of emmetropes became esotropic
Slide 13 Risk Indicator for accommodative ET • In a population of 34 newborns to parents/ siblings with accommodative ET • 6 children (18%) all of which were hyperopic were found to have accommodative esotropia. • Abrahamsson et al (1999) hyperopia and family history were more predicative of esotropia if found together.
Slide 14 Risk Indicator for accommodative ET • Persistence of hyperopia is also a factor • Reduced binocular vision and anisometropia may also influence the outcome of hyperopia. (these factors are very difficult to separate) • Ethnicity
Slide 16 • Why do some patients with high hyperopia escape strabismus • Von Noorden suggested subnormal stimulus ACA ratios
Slide 17 Preventing accommodative ET in hyperopes • Ingram et al (1990) 6m with hyperopia • 152 treatment (specs) 13% ET • 154 no treatment 18% ET • Not significant even when corrected for poor wear • Ingram et al (1990) 12m with hyperopia • 144 treatment 24% ET • 141 No treatment 26% ET
Slide 18 Preventing accommodative ET in hyperopes • Atkinson et al • 68 treatment 8.8% strabismic • 56 no treatment 23.2% strabismic • This was not confirmed by a second study • The value of early spectacles in early hyperopia is still unclear
Slide 19 • Can dynamic retinoscopy help? • An objective assessment of an infants accommodation. • Can we pick those individuals who may develop accommodative ET?