News About the OMA

A study titled "Computerised Hess VS Lee Screen Test in Strabismus Assessment" was published in the Transactions of the 26th European Strabismological Association Meeting, Barcelona, Spain, September 2000. 

Studies from Reading and Cardiff comparing OMA with Lee Screen test were presented at the British Isle Strabismological Association (BISA) 2005 and 2006 and British & Irish Orthoptic Society (BIOS) 2007 showed the OMA to induce more exo compared with the Lee screen test. This was though most likely due the different testing distances at around 26 cm for the OMA and 50 cm for the Lee screen test.

The OMA testing distance was increased to around 35 cm. To allow this, the degrees outside the primary position that are tested has been decreased from 45º (for the 26 cm distance) to 37º for the 35 cm testing distance. This distance is more in line with the orthoptic assessment for near which is usually at around 1/3 of a meter. This figure is similar to that of the Lee screen test. Reading had performed a study on the OMA using this testing distance. This study was presented as posture at the BISA meeting to be held in Brighton, October 2007.

The Reading study conclusions: (please click Reading study to view the graphs)

• The new adaptation to the OMA has reduced exo-error to acceptable levels.
• The new OMA still produces more exodeviation  than the Lees screen
• There is a significant correlation between exodeviation with the OMA and near exophoria
• The Lees screen appears to underestimate near exodeviation while the adapted OMA reflects near exophoria
• Recorded exodeviation is related to testing distance

Recently we have started using a larger display screen (50"+) which allows a testing distance of around 40 cm.

An article published comparing of technical features and testing methods of the OMA and Lee screen ocular motility tests. This was presented at the European Strabismological Association (ESA) Meeting held in Munich, 2008. Download the article OMA vs Lee Screen Testing: