Sains Malaysiana 30: 143-151 (2001)                                                                           Sains Hayat/

        Life Sciences

Hubungan antara Ujian TNO Penataran Biasa dan Penataran

Songsang dengan Stereopsis Silang dan Stereopsis Tak Silang

(Relationship Between Usual and Reverse Presentation TNO Test Using

Crossed and Uncrossed Stereopsis)

Faudziah Abd. Manan

Jabatan Optometri

Fakulti Sains Kesihatan Bersekutu

Universiti Kebangsaan Malaysia

Jalan Raja Muda Abdul Aziz

50300 Kuala Lumpur, Malaysia

ABSTRAK

Persepsi tiga dimensi boleh dikategorikan kepada stereopsis silang apabila suatu objek kelihatan mendekati pemerhati dan sebagai stereopsis tak silang apabila suatu objek kelihatan menjauhi pemerhati. Keadaan ini boleh dikesan daripada ujian steropsis titik rawak TNO berdasarkan penataran plat ujiannya, iaitu penataran biasa memberi apresiasi objek kelihatan mendekati (stereopsis silang), manakala secara penataran songsang plat ujian yang memberi apresiasi objek kelihatan menjauhi pemerhati (stereopsis tak silang). Ini disokong oleh tanggapan umum bahawa stereopsis silang mempunyai nilai ambang yang lebih baik berbanding stereopsis tak silang. Kajian ini tidak menunjukkan perbezaan yang signifikan antara stereoakuiti penataran biasa dan stereoakuiti penataran songsang, sesi A: T = 7, p = 0.89 dan sesi B : T = 2, p = 0.27. Keputusan kajian juga menunjukkan tiada perbezaan yang signifikan antara stereoakuiti diukur dengan penataran biasa kali pertama diikuti oleh ukuran kali ke dua (T = 8, p = 0.6) dan stereoakuiti diukur dengan penataran songsang kali pertama diikuti ukuran kali ke dua (T = 6, p = 0.6). Hasil kajian ini merumuskan apresiasi stereopsis secara penataran biasa plat TNO tidak boleh dianggap sebagai stereopsis silang dan apresiasi stereopsis secara penataran songsang plat TNO tidak mewakili steropsis tak silang dengan alasan yang dinyatakan. Tiada kesan pembelajaran dikesan daripada ujian stereopsis titik rawak TNO.

ABSTRACT

A three dimensional perception can be categorised as crossed stereopsis when an object appears to advance towards the observer, and as uncrossed stereopsis when an object appears to recede from the observer. The condition can be appreciated on a TNO random dot stereograms based on the presentation of test plates, that is, the test plate presented right side up gives rise to an advancing appearance of the test object (crossed stereopsis) whilst the test plate presented upside down gives rise to a receding appearance of the test object (uncrossed stereopsis). This assumption has been widely accepted and argued that the threshold for crossed stereopsis is higher than that of the uncrossed stereopsis.  However, the result of the study shows no significant difference is stereoacuity measured with the plates presentated right side up and in stereoacuty measured with the plates presented upside down, session A:T = 7, p + 0.89 and session B:T = 2, p = 0.27. the study also shows no significant difference in the order of the test plate’s presentation  during stereoactivity measurement.  The right side up presentation measured the first and the second time shows T = 8, p = 0.6 and the reversed presentation measured the first and the second time shows T = 6, p = 0.6. The study concludes that strereoscopic appreciation from the usual order of the test plate presentation cannot be regarded as crossed stereopsis and stereoscopic appreciation with the reversed test plate’s presentation does not represent uncrossed stereopsis. No learning effects were shown from TNO random dot stereopsis test.

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