heteropsia

[het″er-op´se-ah] unequal vision in the two eyes.

heteropsia

(hĕt″ĕr-ŏp′sē-ă) [″ + opsis, vision] An inequality of vision in the two eyes.

anisometropia

Condition in which the refractive state of a pair of eyes differs and therefore one eye requires a different lens correction from the other. Correction may induce aniseikonia and when the eyes deviate from the optical axes of the lenses, anisophoria. Uncorrected anisometropia of low amounts may cause eyestrain or diplopia. Large amounts rarely cause symptoms as one of the retinal images is typically suppressed or there is amblyopia. Syn. asymmetropia; heterometropia; heteropsia. See aniso-accommodation; antimetropia; differential prismatic effect; isometropia.
compound hypermetropic anisometropia See anisohypermetropia.
compound myopic anisometropia See anisomyopia.
mixed anisometropia See antimetropia.
simple anisometropia Anisometropia in which one eye is emmetropic and the other either hypermetropic (simple hypermetropic anisometropia) or myopic (simple myopic anisometropia).

Table A10 Approximate retinal image size differences (in %) for various anisometropias corrected by spectacles (vertex distance = 12 mm)
		refractive anisometropia^†
anisometropia difference (D)	axial anisometropia (%)*	hyperopic (%)	myopic (%)
1.0	0.25	1.50	1.25
1.5	0.37	2.25	1.88
2.0	0.50	3.00	2.50
2.5	0.62	3.75	3.12
3.0	0.75	4.50	3.75
3.5	0.87	5.25	4.38
4.0	1.00	6.00	5.00
4.5	1.12	6.75	5.62
5.0	1.25	7.50	6.25
5.5	1.37	8.25	6.88
6.0	1.50	9.00	7.50
* The two eyes are assumed to be of the same refractive power but of different lengths.^†The two eyes are assumed to be of the same length but of different refractive powers.