The subjects in the group with smaller deviation showed better performance on all the four stereo tests and over 90% demonstrated presence of fusion. When compared to TNO and Randot for determining presence of stereopsis, the horizontal Lang two-pencil test demonstrated sensitivity of 100% and 83.9%, specificity of 77.8% and 73.7%, and negative predictive value of 100% and 100% respectively. It also showed 100% specificity as a test for binocularity when compared with the Bagolini striated glass test. The TNO stereo test was performed by placing the plates at a test distance of 40 cm squarely in front of the patient, wearing spectacle correction if using one. The test consists of seven plates, the first three of which were used for screening to detect the presence of gross stereopsis.

• The criteria for normal subjects were a BCVA of 20/20 with no significant anisometropia, and who were orthophoric.
• We found that the easily performed horizontal Lang two-pencil test detected all subjects who had stereopsis.
• But these tasks could also be done monocularly, if the subject sees the top of the tumbler or the tip of the examiner’s pencil ‘end-on’ in the vertically held pencil test.
• We live in a world of instant gratification and that is the same when it comes to assessments.
• In addition, with no false negative responses and a 100% sensitivity and negative predictive value (NPV), this test may be used as a potential screening test for detecting gross stereopsis.

You are printing and shipping, sometimes with hundreds of trucks around the country. Then you need to get all the exams back, which is even more of a logistical lift. However, there are many situations where paper remains the only option, such as poor tech infrastructure. Paper and pencil testing is often more cost-efficient in certain situations where the organization does not have access to a professional assessment platform or learning management system. The pencil test is a method of assessing whether a person has Afro-textured hair. In the pencil test, a pencil is pushed through the person’s hair.

Determines the film hardness by pencil test (Wolff-Wilborn) in accordance with ISO 15184 and ASTM D3363

In conclusion, the horizontal Lang two-pencil test, an easily performed test even in children, with a high sensitivity and negative predictive value can be used as a potential bedside test to detect stereopsis and binocularity. We live in a world of instant gratification and that is the same when it comes to assessments. Unlike online exams which have options to keep the students engaged, offline exams are open to constant destruction from external factors. Any level of measurable stereo-acuity on the Randot (up to 500 sec of arc) or TNO (up to 480 sec of arc) was considered as presence of stereopsis. False positive is defined as the absence of measurable stereo-acuity on the TNO or Randot, but presence of gross stereopsis on the synoptophore or horizontal Lang two-pencil test.

However, in those without stereopsis, all but one patient (false positive) showed absence of stereopsis on the synoptophore. Evaluation using the horizontal Lang two-pencil test showed that all the patients with stereopsis were picked up correctly and there were four false positive results. Examination using the Bagolini striated glass test for binocularity showed that all the patients with stereopsis had binocular single vision. However, 14 of the 18 patients with no measurable stereo-acuity also showed presence of binocular single vision (data not shown). The study was to compare any level of measurable stereo-acuity on the two stereo tests, namely TNO and Randot, with the gross stereopsis detected by the horizontal Lang two-pencil test. Therefore, comparison of patients with random dot versus local stereopsis was not performed.

Paper-and-Pencil Testing: Still around?

Second, the pencil test is a qualitative test, it should be used purely for screening especially in situations where quantitative tests like the TNO, Randot and Frisby are not readily available. Unlike traditional exams which are limited to a certain number of question types, online exams offer many question types. Videos, audio, drag and drop, high-fidelity simulations, gamification, and much more are possible. Most people think that offline exams are cheat-proof but that is not the case. Most offline exams count on invigilators and supervisors to make sure that cheating does not occur.

Traditional methods of hand-scoring paper tests are slow and labor-intensive. Another advantage of paper exams is that they can often work better for students with special needs, such as blind students which need a reader. Offline exams have been a stepping stone towards the development of modern assessment models that are more effective. We can’t ignore the fact that there are several advantages of traditional exams.

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The Lang two-pencil test by Lang, was originally described to be performed by approaching the rod vertically so as to mimic the daily tasks which requires stereopsis, such as pouring liquid into a tumbler, or hitting a nail. But these tasks could also be done monocularly, if the subject sees the top of the tumbler or the tip of the examiner’s pencil ‘end-on’ in the vertically held pencil test. This can be more easily avoided if the test is performed by approaching the rod/ examiner’s pencil horizontally at the eye level of the subject. We believe that the horizontal Lang two-pencil test gives a more accurate assessment for the detection of gross stereopsis.

A subgroup analysis was done for the subjects in Group 1 between those with and without stereopsis. There were 26 subjects with stereopsis (25 had measurable stereo-acuity levels and one had only gross stereopsis) and 18 without stereopsis. Of the 26 with stereopsis, two were missed on the synoptophore. One of these patients had stereo-acuity of 480 arc seconds on the TNO and the other had stereo-acuity of 400 arc seconds on the Randot.

Pencil Hardness Test

The advantage of the Lang two-pencil test is that it does not require any special instruments/ equipments like goggles and test plates and it can be easily performed in younger children. They found that any of the tests could be used as a supplement to the ophthalmological examination to pick up an orthoptic pathology, which would then require detailed evaluation. We feel there is a possibility of false positive error if the pencils are held vertically because then the task could also be done monocularly, if the subject sees the tip of the examiner’s pencil ‘end-on’. The purpose of this study was to assess the Lang two-pencil test used horizontally as a test to detect gross stereopsis and to compare it with the TNO and Randot stereo-acuity tests. The Lang two-pencil test has not been extensively studied as an adjunct to the orthoptic/ ophthalmological evaluation of strabismic patients, or as a screening test for stereopsis. With a 100% sensitivity and NPV, its potential as a screening test is immense.

Clinical evaluation included visual acuity testing, refraction, ocular movement assessment, cover test, and prism bar cover test (PBCT) to determine the amount of deviation. Sensory status examination for binocularity and fusion were performed using the Bagolini striated glass test (a routinely pencil test cases used test), the three circles test on TNO and the R and L test in the Randot booklet. Stereopsis was assessed by the synoptophore, horizontal Lang two-pencil test, TNO and Randot test booklets. TNO or Randot are routinely used stereo tests to determine level of stereo-acuity.

Horizontal lang two-pencil test as a screening test for stereopsis and binocularity

This test was used to determine racial identity in South Africa during the apartheid era, distinguishing whites from coloureds and blacks. The test was partially responsible for splitting existing communities and families along perceived racial lines. Pencils are now an important part of South African cultural heritage and a symbol of racism. If you publish one on the cloud, it can immediately be taken, anywhere in the world. Online exams can be built with tools for zoom, color contrast changes, automated text-to-speech, and other things to support accessibility. This is especially true in areas of the world that do not have the internet bandwidth or other technology necessary to deliver internet-based testing.

The last three plates on the other hand were used to quantitatively assess stereo-acuity in the range of 15 to 480 sec of arc. Each plate consisted of four squares, within which was a circle with a ‘pie’/ piece missing. The normal value for stereo-acuity was considered ≤60 sec of arc. Eighty-four strabismic subjects divided into two groups based on the amount of deviation, and 40 normal subjects were studied.

High candidate-to-ratio is another factor that contributes to cheating in offline exams. To assess the horizontal Lang two-pencil test as a bedside test to detect gross stereopsis. Delivery of paper-and-pencil testing at large scale requires a lot of resources.