Journal List > J Korean Ophthalmol Soc > v.49(8) > 1008053

Chung, Yang, Lew, Lee, and Chang: The Assessment of Stereoacuity in Patients with Strabismus

Abstract

Purpose

To analyze stereoacuity in patients with strabismus using various stereotests.

Methods

Stereoacuity was assessed in children who were diagnosed with intermittent exotropia or refractive accommodative esotropia using the Titmus stereotest, TNO stereotest, and the Lang II stereotest. Patients with amblyopia or previous ocular surgery were excluded.

Results

Ninety-four patients with intermittent exotropia and 36 patients with refractive accommodative esotropia were included; the mean age was 7.2 years. The mean stereoacuity in intermittent exotropia was 143.1±207.9 seconds of arc with the Titmus stereotest, 130.2±103.7 seconds of arc with the TNO stereotest, and 200.0±0.0 seconds of arc with the Lang II stereotest. The mean stereoacuity in refractive accommodative esotropia was 430.3±288.6 seconds of arc, 232.5±90.0 seconds of arc, and 230.0±97.9 seconds of arc, respectively. The absence of stereoacuity was more frequent in patients with refractive accommodative esotropia than in patients with intermittent exotropia, and both groups of patients showed the largest proportion of absent stereopsis with the TNO stereotest. No factor was significant for stereopsis in patients with intermittent exotropia and patients with refractive accommodative esotropia.

Conclusions

Stereoacuity showed various seconds of arc according to the type of stereotest in the same patient. Patients with refractive accommodative esotropia showed lower stereoacuity in all stereotests than patients with intermittent exotropia. TNO stereotests are sensitive enough to detect the absence of stereopsis in patients with strabismus.

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Table 1.
Age of patients
Age (year) 4≤ <5 5≤ <6 6≤ <7 7≤ <8 8≤ <9 9≤ <10 10≤
X(T)* patients 18 21 19 10 9 8 9
ET patients 1 6 8 7 3 4 7
Patient number 19 27 27 17 12 12 16
Percent of total 14.6% 20.8% 20.8% 13.1% 9.2% 9.2% 12.3%

* X(T)=intermittent exotropia;

ET=refractive accommodative esotropia.

Table 2.
Stereoacuity in patients with intermittent exotropia
Stereotest Patient number Percent of total
Titmus ≤50 seconds of arc* 34 36.2%
50< ≤3000 seconds of arc 57 60.6%
no stereopsis 3 3.2%
TNO ≤120 seconds of arc* 59 62.8%
120< ≤480 seconds of arc 26 27.7%
no stereopsis 9 9.5%
Lang II ≤200 seconds of arc 89 94.7%
200< ≤600 seconds of arc 0 0.0%
no stereopsis 5 5.3%

* Criteria of Titmus stereotest and TNO stereotest for normal stereopsis according to Cho et al4;

Criteria of Lang II stereotest for normal stereopsis according to Ohlsson et al9.

Table 3.
Stereoacuity in patients with refractive accommodative esotropia
Stereotest Patient number Percent of total
Titmus ≤50 seconds of arc* 3 8.3%
50< ≤3000 seconds of arc 23 63.9%
no stereopsis 10 27.8%
TNO ≤120 seconds of arc* 2 5.6%
120< ≤480 seconds of arc 14 38.9%
no stereopsis 20 55.5%
Lang II ≤200 seconds of arc 18 50.0%
200< ≤600 seconds of arc 2 5.6%
no stereopsis 16 44.4%

* Criteria of Titmus stereotest and TNO stereotest for normal stereopsis according to Cho et al4;

Criteria of Lang II stereotest for normal stereopsis according to Ohlsson et al9.

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