perfusion-fixed. Results were compared with one uninjured-con-trol piglet. Twelve piglets had bilateral preinjury and postinjuryocular/retinal examination; 14 had bilateral ocular pathologyperformed (8 had both), and 9 had gross/microscopic brain pa-thology. Results: Peak angular-velocity averaged 191 � 14 rad/s(range, 114-248). Clinical and histopathologic ocular examina-tions revealed minimal subarachnoid hemorrhage along one op-tic nerve in one animal and no other ocular abnormalities. Whilelow velocities produced little brain pathology, large velocitiesproduced subdural and subarachnoid hemorrhage, tissue tears,and traumatic injury in central and peripheral white-matter tracts(revealed via immunohistochemistry). Discussion: Pig and hu-man brain development parallels make neonatal piglets a goodmodel for studying the biomechanical environment producingretinal hemorrhages in ICN. Rotational loading reaching 250rad/s was insufficient for retinal hemorrhages but did producebrain injuries. While we expected retinal hemorrhages at largerotational velocities, eye injury was absent even in the presence ofwidespread intracranial hemorrhage. Conclusion: This studyused an animal model under defined biomechanical conditions tostudy the mechanisms of ICN retinal hemorrhages. Future stud-ies should employ increased and/or repetitive loads and sagittalrotations.

Randot Preschool Stereoacuity test: Normative data andvalidity. Eileen E. Birch, Cathy Williams, Drover James,Valeria L.N. Fu, Christina Cheng, Kate NorthstoneIntroduction: The Randot Preschool Stereoacuity test (RPST)is a widely used three-book test for the assessment of binocularstatus. Using a prototype, we reported high testability in childrenas young as 3 years, validity data, and some normative data. Anartifact noted for 1 of the 800 seconds stimuli in the prototypeled to a redesign. Here we report normative and validity data forthe final three-book version of the RPST. In addition, we reportnormative data for a new fourth book that adds finer disparities.Methods: The RPST was administered to 4338 normal childrenages 3 to 18 years and 39 adults in both clinical and screeningsettings. In addition, the RPST along with the new fourth bookthat added 30 and 20 seconds disparity levels was administered to1402 normal children ages 3 to 18 years and 33 normal adults.Both the four-book RPST and the Randot circles were admin-istered to 242 patients aged 3 to 18 years. Results: Mean normalstereoacuity improved from 100 seconds at 3 years of age to 60seconds by 5 years and 40 seconds by 7 years. The lower limit ofnormal was 400 seconds at 3 years, 200 seconds at 4 years, and 60seconds at 7 years. Using the new four-book version, furtherimprovement in mean stereoacuity could be appreciated beyond7 years of age to 30 seconds in the 11- to 18-year-old and adultgroups. Among the 242 patients, RPST stereoacuity (four-booktest) was strongly associated with Randot circle stereoacuity (c2 �261.0, p � 0.001). Conclusions: Normative data for the RPSTshow a monotonic improvement of stereoacuity from age 3 yearsthrough teens. Patient data support the validity of the four-bookversion of the test.

Effectiveness of the Lea Symbols and Random Dot E in alarge preschool vision screening program. Geoffrey E.Bradford, P. Kay Nottingham ChaplinIntroduction: In 2001 the Maternal Child Health Bureau/Na-tional Eye Institute Vision Screening (MCHB/NEI) Task Forcedeveloped interim recommendations for preschool vision screen-ing. This study sought to define the positive-predictive value of

these recommendations in a statewide vision screening programusing the Lea Symbols (LS) and Random Dot E (RDE). Meth-ods: With IRB approval, the Vision Initiative for Children (VIC)developed a vision screening training program incorporating theMCHB/NEI recommendations to certify, equip, and supportcommunity preschool vision screeners. Acuity testing was con-ducted with the LS at a critical line of 20/40 for 3-year-olds and20/30 for 4-year-olds. RDE stereoacuity was done at 40 cm (630arcsec). Results: Since 2001 the VIC Program has certified 978lay screeners. 15,267 screening results have been reported onchildren 36 to 59 months of age. 2841 children failed the visionscreen and were referred to a local optometrist or ophthalmol-ogist for examination. 345 examination results were received andreviewed. 55 children (16%) had amblyopia. An additional 176children (51%) had a significant amblyogenic condition or re-fractive error sufficient for glasses. The overall positive-predic-tive value (PPV) was 67%. Discussion: The PPV for screeningtests used by trained lay screeners in this study compares favor-ably to the PPV of 31% for the Welch-Allen SureSight autore-fractor and is similar or low compared with the PPV of 66 to92% for the MTI Photoscreener. Conclusions: Traditionalscreening with the LS and the RDE achieves a PPV of 67% whenused by certified lay screeners and remains a reasonable, inex-pensive method for use in large screening programs. Adjustingthe passing criteria for one or both of these tests may enhance thePPV, but at the risk of increasing the false-negative value.

Natural animal shaking: A model for inflicted neurotraumain children? Sandra Brown, Alex V. Levin, David Ramsay,Irina SerbanescuShaken baby syndrome (SBS) involves a perpetrator violentlysubjecting an infant to repeated acceleration-deceleration forceswith/without head impact, producing severe acute brain injury.Retinal hemorrhages are a cardinal sign. Rat and mouse modelsyield few eyes with retinal hemorrhages. Animal models raiseethical issues when subjecting even anesthetized animals to abu-sive injury. We studied two kittens and a juvenile common Texasjackrabbit that were captured by an 18 kg mixed-breed canineusing a bite to the haunches or posterior spine with witnessedaggressive side-to-side shaking. Victim animals died before beingdropped by the dog. Enucleated eyes showed no hemorrhage orretinoschisis. This model may not be mechanically consistentwith SBS-type injury. Although the victim animal necks were notimmobilized in the predator’s jaws, it is possible that the greatestflexion occurred midspine rather than in the neck. This couldhave reduced acceleration-deceleration shearing forces withinthe eyes and skull, particularly in the juvenile rabbit, which haswell-developed musculature and lower ratio of head mass to bodymass than human infants. Due to their smaller size, the animaleyes require a greater force to injure than those of human infants.The amount of force generated by an 18 kg dog may be insuf-ficient to cause SBS-like injury. The feline head and neck mayalso be better equipped to sustain acceleration-decelerationforces without injury. Other models will be necessary to studySBS. Note: REB approval not required and not applicable.

Ocular manifestation of Kawasaki disease. Yoon-HeeChang, Marvin Lee, Jo Won Jung, Jaehong Ahn, Hong SukYang, Kyung Hoon KookIntroduction: Kawasaki disease is a febrile, exanthematous dis-ease of children that has potentially fatal complications. Themajor criteria include fever, skin eruption, ocular changes, oral

Volume 11 Number 1 February 2007 Abstracts 85

Journal of AAPOS