D . move finger or object equidistant from you and client outside of own field of vision . slowly bring it back into field , asking client to state when it is first seen . repeat procedure for all visual fields and for both eyes 在检查者与受检者等距离处移动手指或物体至自身视野外。缓缓移进视野，告诉病人在第一眼看到手指或物体时就告诉检查者。各个方位重复操作，检查双眼。
In a general term , the annual updating only involves using existing gis database ( with minor changes ) and methodology to repeat operations to produce lup and lut with new satellite image data , while the triennial updating involves re - visiting data sources and possible alternations in methodology 一般地说，年度更新只涉及采用现有gis资料库（可有局部更新）和技术进行重复操作，以便利用新的卫星图像资料编制土地利用图和土地利用表。另一方面，三年制更新涉及再次建立资料源，还可能改变资料处理方法。
