AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020

Ophthalmology Terms
Nomenclature

Some terms described in this section are specific to ophthalmology, and others have special usage requirements in ophthalmology (see 11.0, Correct and Preferred Usage).

adnexa oculi.

Although often used as a synonym for eyelids, the term adnexa oculi (which is plural) properly includes the eyelids, lacrimal apparatus, and other appendages of the eye and should be used with its inclusive meaning.

diopter.

The diopter is a measure of the power of an optical lens and is the reciprocal of the focal length in meters. Diopter is abbreviated D when used with a number.

diopter sphere

diopter cylinder

conversion from diopters to millimeters

correction of 10.5 D

The prism diopter is a measure of the power of a prism and represents a 1-cm deflection of an image at a distance of 1 m. Its symbol, ∆, may be used with numbers after first mention.

The left eye showed an improvement, with only 25—prism diopter hypotropia.

distance exotropia = 35 prism diopters (∆); near exotropia = 5∆

disc, cup-disc ratio.

For the optic disc, spell as disc (not disk). The cup-disc ratio refers to the ratio of the diameter of the optic cup (a central area devoid of nerve fibers within the optic disc) to diameter of the optic disc.

cup-disc ratio of 0.6

It can be useful to specify whether the ratio is vertical, horizontal, or other.

The mean (SD) horizontal cup-disc ratio by contour estimated from stereophotography was 0.36 (0.18).

disc diameters, disc areas.

Disc diameters (DDs) may be used to indicate location or dimension of findings on the ocular fundus with relative distances expressed as diameters of the optic disc.

2 DDs inferior to the fovea

Lesions varied from 0.5 to 4.5 disc diameters (DDs; median, 2.0 DDs) for the first group, 0.75 to 7.5 DDs (median, 2.5 DDs) for the second group, and 1.0 to 9.0 DDs (median, 4.0 DDs) for the last group.

Disc areas (DAs) are also used to indicate relative sizes of findings on the ocular fundus, as well as in considerations of the size of the disc.

A scar in the center of the retina, presumably from toxoplasmosis, occupied approximately 6 disc areas of the central macula.

Substantial ischemia was defined as greater than 10 disc areas of retinal capillary nonperfusion.

Disc areas (DAs) were measured using objective techniques. The mean DA for the patients in group 1 was 2.57 mm².

electroretinogram, pattern electroretinogram.

Waves of the electroretinogram (ERG) are as follows:

An ERG may be described as normal, subnormal, or negative. Do not substitute one of these terms for another. (For visual evoked potentials, see 14.11.3, Evoked Potentials or Responses.)

Waves of the pattern electroretinogram (PERG)¹ are as follows:

Two main components of the PERG are the P50 wave, a positive-deflection waveform, and the N95 wave, a negative-deflection waveform. The terms P50 and N95 may be used without expansion.

fovea, macula.

The center of the macula is the fovea. The terms fovea and macula should be used specifically and not interchangeably. Similarly, areas defined on imaging of the macula (such as on optical coherence tomography) should refer to the center point as the center of the image and central subfield as the central area of the image.

Goldmann perimetry.

This is a method of assessing the visual field. The test stimuli are described by means of a 3-part term: spot size is designated with roman numerals I through V, and luminance is designated with arabic numerals 1 through 4 and letters a through e. For example:

I-4-e isopter area

I-2-e test object

V-4-e light

greatest linear dimension.

This is the greatest dimension between 2 points on the boundary of a lesion.

Lesion size was less than or equal to 9 disc areas, and greatest linear dimension was less than or equal to 5400 µm.

injection.

When used to indicate excess blood, engorgement, or dilation of a vessel, injection should be changed to hyperemia or vasodilation (eg, conjunctival hyperemia or conjunctival vasodilation [not conjunctival injection]).

intraocular pressure.

Measurements of intraocular pressure (IOP) should include the method used (eg, Goldmann applanation tonometry) and, if determined, the corneal thickness measurement.

Substantial postoperative astigmatism led to marked overestimation of the intraocular pressure (56 mm Hg) as measured with Goldmann aplanation tonometry with the mires in the standard horizontal position.

intravitreous, intravitreal.

Intravitreous is an adjective and should precede nouns, such as an injection (eg, intravitreous injection). Intravitreal is an adverb and should precede verbs, unless part of a name in which intravitreal was used as an adjective (eg, dexamethasone intravitreal implant).

lasers.

Lasers used in ophthalmology include the following:

argon laser

erbium:YAG laser

eximer laser

holmium:YAG laser

krypton laser

Nd:YAG laser

photodynamic therapy laser

Q-switched Nd:YAG laser

transpupillary thermal therapy

The term Nd:YAG (neodymium:yttrium-aluminum-garnet) may be used without expansion.

lids.

Lids should be changed to eyelids.

masked.

Masked rather than blinded should be used in the ophthalmologic literature when referring to randomization or assessment of research participants or outcomes, if there could be confusion.

OD, OS, OU.

These abbreviations may be used without expansion only with numbers (eg, 20/25 OU) or descriptive assessments of acuity (eg, counting fingers OS; see Visual acuity, vision) (Table 14.13-1).

Table 14.13-1. Explanation of Acuity Abbreviations

Note that OU means each eye, not both eyes, although it is often used incorrectly to imply a vision measurement (eg, visual acuity or visual field) with both eyes at the same time (see Visual acuity, vision).

ophthalmoscopy.

Ophthalmoscopy refers to visualization of the eye with an ophthalmoscope; the term funduscopy is not considered a word because it would imply visualization with a “funduscope,” which is not an instrument.

orbit.

Orbit refers to the bony cavity that contains the eyeball and its adnexa (muscles, vessels, nerves). It should be clear to readers whether authors are referring to the orbit, the specific bones that compose it, the structures that fill the orbit, or a combination of these.

visual acuity, vision.

Distinguish between vision, a general term, and visual acuity, measurable clearness of vision. If a measurement is given (eg, 20/20 [see below]), use visual acuity. Change “unaided vision” to “acuity without correction” (see 11.0, Correct and Preferred Usage). Authors should report the visual acuity in the manuscript using the same nomenclature that was used in the study. Typically, visual acuities are collected as logMAR (base 10 logarithm of the minimum angle of resolution) values, letter scores, decimal fractions, or Snellen fractions (using meters or feet). However, evidence² suggests that many readers, at least in the US, best understand visual acuity measurements when given as Snellen equivalents. For example, authors of manuscripts submitted to JAMA Ophthalmology are requested to provide the approximate Snellen equivalent in feet (20/20, 20/40, etc) in parentheses next to each visual acuity that is not in this Snellen format throughout the manuscript, including figures and tables.³ The methods used to provide the appropriate Snellen equivalent visual acuities should be given in the Methods section of the manuscript and should be based on published data, for example, as provided by Ferris and colleagues⁴ and the Diabetic Retinopathy Clinical Research Network.⁵ Always list the visual acuity scores from best to worst when listing more than one (eg, 20/63 to 20/100) or letter scores of 60 (20/63) to 59 (29.100).

distance acuity.

The Snellen eye chart is a well-known method of assessing distance visual acuity, resulting in the Snellen fraction, an expression such as 20/15, 20/20, or 20/60. The first number represents the testing distance from chart to patient; the second number represents the smallest row of letters that the patient can read. For example, acuity of 20/40 indicates that at 20 ft the smallest line read is readable by a normal eye at 40 ft. Do not add Snellen equivalents for differences in letter scores.

The units for distance acuity are feet (eg, 20 ft) or meters (eg, 6 m). By convention, acuity is expressed without these units specified (eg, 20/20). The JAMA Network journals follow the author’s preference in expressing distance acuity equivalents as metric (eg, 6/6) or English (20/20) and do not convert English fractions to metric or vice versa. Only one type, English or metric, should be used throughout a manuscript.

Visual acuity is assessed separately for each eye. Other means are also used to assess visual acuity, such as counting fingers (CF), hand motions (HM), and light perception (LP), which may be expanded as LP with projection, LP without projection, or no LP (NLP). Express visual acuity, including numerical measures and other means, by using OD or RE (right eye) and OS or LE (left eye) (see OD, OS, OU).

The visual acuity was 20/40 OD and counting fingers OS.

Not: The visual acuity was 20/40 OD and counting fingers in the left eye.

Another method of assessing visual acuity makes use of the Bailey-Lovie or Early Treatment Diabetic Retinopathy Study (ETDRS) or electronic ETDRS (e-ETDRS) acuity charts and designates acuity using logMAR. A logMAR of 0.0 is equivalent to 20/20 Snellen (Table 14.13-2). LogMAR visual acuities always should be expressed in logMAR. Note that logMAR does not require expansion.

Table 14.13-2. Table of Equivalent Visual Acuity Measurements^a

^a Adapted with permission from Ferris et al.⁴ Copyright 1982 Elsevier.

letter scores vs letters.

Because Bailey-Lovie or ETDRS or e-ETDRS charts follow a protocol of recording letters read and then computing a letter score, visual acuities from these charts should provide visual acuities as letter scores, not letters (Table 14.13-3). For example,

Table 14.13-3. Visual Acuity Score Conversion^a

^a Adapted with permission from the Diabetic Retinopathy Clinical Research Network website.⁵

The best-corrected visual acuity letter score was 55 (approximate Snellen equivalent 20/80).

(Not: The best-corrected visual acuity was 55 letters.)

However, improvement or loss can be in letters. For example,

The mean change in visual acuity from baseline to 2 years among eyes assigned to laser treatment was 7 letters.

near visual acuity.

Near visual acuity (reading vision) may be reported by means of Snellen equivalents or the Jaeger system (J values, ranging from J1 to J11). J2 is equivalent to Snellen 20/20.⁶

visual field.

The extent of the visual field is described by means of degrees from a central point from 0° through 90°:

85° temporally

65° nasally

56° up and nasally

vitreous.

Vitreous may be used as a noun or an adjective. Typically, avoid vitreal and intravitreal in all contexts (change intravitreal to intravitreous).

Principal Author: Cheryl Iverson, MA

Acknowledgment

Thanks to Neil M. Bressler, MD, editor JAMA Ophthalmology, and Retina Division, Johns Hopkins Medicine, Baltimore, Maryland, for reviewing and providing comments. Thanks also to David Song, JAMA Network, for obtaining permissions.

References

1.Bach M, Brigell M, Hawlina M, et al. ISCEV standard for clinical pattern electroretinography (PERG): 2012 update. Doc Ophthalmol. 2013;126(1):1-7. doi:10.1007/s10633-012-9353-y

2.Lopes MS, Zayit-Soudry S, Moshiri A,Bressler SB, Bressler NM. Understanding and reporting visual acuity measurements in publications of clinical research. Arch Ophthalmol. 2011;129(9):1228-1229. doi:10.1001/archophthalmol.2011.248

3.Bressler N, Beck RW, Kass MA. JAMA Ophthalmology publication policies and procedures: fresh start for a new year. JAMA Ophthalmol. 2014;132(1):11-12. doi:10.1001/jamaophthalmol.2013.7874

4.Ferris FL III, Kassoff A, Bresnick GH, Bailey I. New visual acuity charts for clinical research. Am J Ophthalmol. 1982;94(1):91-96. doi:10.1016/0002-9394(82)90197-0

5.Information for investigators: visual acuity score conversion chart. Accessed August, 1, 2019. http://publicfiles/jaeb.org/drcrnet/Misc/VAScoreConversionChart.pdf

6.Visual acuity conversion chart. Accessed August 1, 2019. https://www.healio.com/~/media/Files/Journals/General/PDFs/JRSVACHART.pdf