A new specialized visual acuity chart for amblyopic children aged 3-5 years old:development and its clinical applications

AIM:To Introduce a new specialized visual acuity chart for amblyopic children aged 3-5 years old and its clinical applications.METHODS:The new visual acuity chart and notations were designed based on Weber-Fechner law.The optotypes were red against a white background and were specially shaped four basic geometric symbols:circle,square,triangle,and cross.A regular geometric progression of the optotype sizes and distribution was employed to arrange in 14 lines.The progression rate of the optotype size between two lines was 1.2589 and the testing distance was 3m.Visual acuity score could be recorded as logMAR notation or decimal notation.Agestratified diagnostic criteria for amblyopia established by consensus statement on diagnosis of amblyopia(2011)among members of the Strabismus and Pediatric Ophthalmology Group,Ophthalmology Society,Chinese Medical Association(SPOGOSCMA)were illustrated in the new visual acuity chart.RESULTS:When assessing visual acuity in children aged 3-5 years old,this new visual acuity chart that consists of four symmetrical shapes(triangle,square,cross,and circle)overcame an inability to recognize the letters of the alphabet and difficulties in designating the direction of black abstract symbols such as the tumbling’E’or Landolt’C’,which the subjects were prone to lose interest in.The visual acuity score may be recorded indifferent notations:decimal acuity and logMAR.These two notations can be easily converted each other in the new eye chart.The measurements of this new chart not only showed a significant correlation and a good consistency with the international standard logarithmic visual acuity chart(r=0.932,P【0.01),but also indicated a high test-retest reliability(89%of retest scores were within 0.1 logMAR units of the initial test score).CONCLUSION:The results of this study support the validity and reliability of distance visual acuity measurements using the new eye chart in children aged3 to 5 years over a wide range of visual acuities,and the new eye chart is great for early detection of amblyopia.It can be applied in various clinical settings.

Add-on perceptual learning on refractive amblyopia in children

AIM:To evaluate the visual outcomes of standard amblyopic treatment add-on training via perceptual learning in refractive amblyopic children and to identify the risk factors for treatment failure.METHODS:Retrospective charts were reviewed in children with refractive amblyopia who received standard treatment and add-on Cambridge Visual Stimulator(CAM)training.The add-on CAM group that was enrolled had worn full-corrected glasses for at least 2mo before training.A control group received only the standard treatment.Treatment success was defined as best-corrected visual acuity(BCVA)≥20/25.The age,sex,initial BCVA,refractive errors,sessions and duration of training,and final BCVA were recorded.RESULTS:A total of 209 children(129 children in add-on CAM group and 80 children in control group)were enrolled.Seventy-six percent of unilateral and 87%of bilateral amblyopic children achieved treatment success.In children with unilateral or bilateral moderate amblyopia,the duration to reach BCVA≥20/25 was significantly shorter in add-on CAM group than in control group.Poor initial BCVA(P<0.001)and high astigmatism(P=0.007)were risk factors for treatment failure after add-on CAM training.Age,sex,and types of refractive error were not associated with treatment success.CONCLUSION:Add-on CAM training is an effective strategy for visual improvement and can shorten the treatment course when the effect of standard treatment is limited in amblyopic children.