Words Used in Eye Care: What You Thought They Meant and What They Actually Mean

Even when ophthalmologists and orthoptists use the same words as patients, they often understand them in different ways.

If these gaps pile up, an explanation may never get across, and you may end up in a state of “I don’t know why I’m continuing treatment.”

I would like to start explanations by aligning the meanings of words.

Word	What patients imagine	What it actually means in ophthalmology	Related article
Visual acuity	Common image Uncorrected (naked-eye) vision	Actually “Corrected visual acuity” through trial lenses adjusted during the examination	▶What do myopia, hyperopia and astigmatism mean? ▶Pediatric ophthalmology
Visual acuity 1.0 (1.2, 1.5)	Common image A perfect eye; anything higher is the best	Actually Only the resolving power of a very small part of the center. Visual field, color vision and night vision are entirely separate	▶Definition and evaluation of glaucoma
Conjunctivitis	Common image It is contagious	Actually Inflammation in general of the “conjunctiva,” the white of the eye and the inner surface of the eyelids. It combines a “place” and an “inflammation,” so the meaning is very broad. Few forms of conjunctivitis are contagious	▶Causes of conjunctivitis
Myopia	Common image Is it hard to see far? Is it hard to see near?	Actually The eyeball is long from front to back	▶What do myopia, hyperopia and astigmatism mean?
Hyperopia	Common image Is it hard to see near? Is it hard to see far?	Actually The eyeball is short from front to back	▶What do myopia, hyperopia and astigmatism mean?
Presbyopia	Common image Something like hyperopia	Actually The focusing part inside the eye becomes stiff	▶What is presbyopia?
Astigmatism	Common image Vision gets distorted; eyesight is poor	Actually A distortion in the shape of the eye. It is about shape, not about how things look	▶What do myopia, hyperopia and astigmatism mean?
Inside the eye	Common image The place where contact lenses go and where dust gets in	Actually The contents of the eyeball. The place where contact lenses sit and where dust gets in is “outside the eye”	[Outside the eye] Dust getting in, the place where contact lenses are put, conjunctivitis ▶Conjunctivitis [Surface of the eye] LASIK, keratitis, a white spot on the black of the eye ▶LASIK / ICL ▶Keratitis [Inside the eye: the lens] Cataract, ICL ▶ICL ▶Cataract [Inside the eye: vitreous, retina, optic nerve] Floaters, retinal detachment, glaucoma ▶Floaters ▶Retinal detachment ▶Glaucoma
Amblyopia	Common image Weak eyesight, or weak vision	Actually A state in which the ability to process images in the back part of the brain has not developed. (There is no abnormality in the structure of the eyeball)	▶Causes of amblyopia ▶Early detection of amblyopia ▶Amblyopia and glasses
Visual field test	Common image A test to see whether the visual field is narrow or has missing parts	Actually A test that measures light sensitivity at each part of the “retina,” the part equivalent to the film of a camera or the sensor of a smartphone camera	▶Definition and evaluation of glaucoma
Cataract	Common image A white film forms over the eye. Others can tell by looking	Actually The “lens” of the eyeball becomes cloudy. It usually cannot be detected without an ophthalmic microscope	▶Timing of cataract surgery
Glaucoma	Common image A disease in which the eye turns green? Something like cataract?	Actually A disease in which the “optic nerve,” the cable connecting the brain and the eyeball, is damaged. It is normally unrelated to eye color	▶Basics of glaucoma ▶Definition and evaluation of glaucoma
Glaucoma	Common image Glaucoma leads to blindness	Actually Today, testing and treatment have advanced, and in many cases it can be controlled so that symptoms never appear over a lifetime	▶The gradation of glaucoma
High eye pressure = glaucoma	Common image If eye pressure is low, it is not glaucoma and you can relax	Actually Glaucoma can occur regardless of eye pressure. Eye pressure is only one indicator	▶Basics of glaucoma ▶Definition and evaluation of glaucoma
Dry eye	Common image The eyes feel dry	Actually A problem of the quality, quantity and stability of tears. You can have dry eye even if your eyes are not dry	▶Dry eye that doesn’t feel dry
Blue light	Common image Blue light is bad for the eyes	Actually At present there is no evidence. Blue-light-cut products can sometimes be harmful	▶Blue light and digital eye strain
Stye	Common image It is contagious (“moraibyo”)	Actually Inflammation of the eyelid caused by bacterial infection or a blocked oil gland. It is not contagious	▶Stye

It is important to align the meaning you have in mind now with the actual meaning in ophthalmology.
If you feel that something is not coming across in the examination, please do not hesitate to ask, “What does that mean?” It leads to accurate judgment and treatment.

(This list will be added to and revised as appropriate)