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Esophoria is an eye condition involving inward deviation of the eye, usually due to extra-ocular muscle imbalance. It is a type of heterophoria. Cause. Causes include: Refractive errors; Divergence insufficiency; Convergence excess; this can be due to nerve, muscle, congenital or mechanical anomalies.
Amblyopia. Anisometropia is a condition in which a person's eyes have substantially differing refractive power. [1] Generally, a difference in power of one diopter (1D) is the threshold for diagnosis of the condition . [2] [3] Patients may have up to 3D of anisometropia before the condition becomes clinically significant due to headache, eye ...
The retina (from Latin rete 'net'; pl. retinae or retinas) is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs.The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception.
Heterophoria is an eye condition in which the directions that the eyes are pointing at rest position, when not performing binocular fusion, are not the same as each other, or, "not straight". This condition can be esophoria , where the eyes tend to cross inward in the absence of fusion; exophoria , in which they diverge; or hyperphoria, in ...
Schematic diagram of the human eye. It shows a horizontal section through the right eye. The eye is made up of three coats, or layers, enclosing various anatomical structures. The outermost layer, known as the fibrous tunic, is composed of the cornea and sclera, which provide shape to the eye and support the deeper structures.
The prism cover test ( PCT) is an objective measurement and the gold standard in measuring strabismus, i.e. ocular misalignment, or a deviation of the eye. [1] It is used by ophthalmologists and orthoptists in order to measure the vertical and horizontal deviation and includes both manifest and latent components. [1]
Eye strain, also known as asthenopia (from Greek a-sthen-opia, Ancient Greek: ἀσθενωπία, transl. weak-eye-condition ), is a common eye condition that manifests through non-specific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache, and occasional double vision. [1] Symptoms often occur after long-term use ...
The macula is an oval-shaped pigmented area in the center of the retina of the human eye and other animal eyes. Its center is shifted slightly away from the optical axis (laterally, by 5°=1.5 mm). [6] The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea ...
Entoptic phenomena (from Ancient Greek ἐντός (entós) 'within', and ὀπτικός (optikós) 'visual') are visual effects whose source is within the human eye itself. (Occasionally, these are called entopic phenomena, which is probably a typographical mistake.) In Helmholtz 's words: "Under suitable conditions light falling on the eye ...
Contents. Perifovea. Photograph of the retina of the human eye, with overlay diagrams showing the positions and sizes of the macula, fovea, and optic disc. Perifovea is a region in the retina that circumscribes the parafovea and fovea and is a part of the macula lutea. [1] The perifovea is a belt that covers a 10° radius around the fovea and ...