46 CFR 10.305: Vision standards for mariner credentials
Last reviewed: October 14, 2026
This section sets the vision and color-sense standards a mariner must meet. Deck, engineering, Radio Officer, tank vessel endorsement, and MODU mariners have different acuity standards. It also covers vision waivers, the corrective lens limitation, and loss of vision in one eye.
Applies toMariners and applicants for deck, engineering, Radio Officer, tank vessel endorsement, and MODU endorsements, including applicants for an STCW endorsement.
What it says
Under the deck standard, a mariner must have correctable vision to at least 20/40 in one eye and uncorrected vision of at least 20/200 in the same eye.
46 CFR 10.305(a)(1)“A mariner must have correctable vision to at least 20/40 in one eye and uncorrected vision of at least 20/200 in the same eye.”
Applicants for an STCW endorsement must have correctable vision to at least 20/40 in both eyes and uncorrected vision of at least 20/200 in both eyes.
46 CFR 10.305(a)(2)“Applicants for an STCW endorsement must have correctable vision to at least 20/40 in both eyes and uncorrected vision of at least 20/200 in both eyes.”
Under the Engineering, Radio Officer, tank vessel endorsement, and MODU standard, a mariner must have correctable vision to at least 20/50 in one eye and uncorrected vision of at least 20/200 in the same eye.
46 CFR 10.305(b)“A mariner must have correctable vision to at least 20/50 in one eye and uncorrected vision of at least 20/200 in the same eye”
An applicant whose uncorrected vision does not meet the 20/200 standard but is correctable to the listed standards may be granted a medical waiver in accordance with § 10.303.
46 CFR 10.305(c)“may be granted a medical waiver in accordance with § 10.303.”
If a vision waiver is granted, the medical certificate will carry a limitation that the mariner may not serve under the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel.
46 CFR 10.305(c)“the mariner may not serve under the authority of the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel.”
If corrective lenses are required to meet the vision standards, the mariner may not serve under the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel.
46 CFR 10.305(d)“a mariner may not serve under the authority of the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel.”
A mariner who has lost vision in one eye must wait 6 months from the date of the vision loss before submitting any application, and must provide a statement of demonstrated ability on the medical examination.
46 CFR 10.305(e)“must wait 6 months from the date of the vision loss before submitting any application, and must provide a statement of demonstrated ability on their medical examination.”
Common questions
What vision do I need for a deck endorsement?
A mariner must have correctable vision to at least 20/40 in one eye and uncorrected vision of at least 20/200 in the same eye.
“A mariner must have correctable vision to at least 20/40 in one eye and uncorrected vision of at least 20/200 in the same eye.”
Do I have to carry spare glasses on board?
Yes, if corrective lenses are required to meet the vision standards. The mariner may not serve under the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel.
“a mariner may not serve under the authority of the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel.”
How long must I wait after losing vision in one eye?
A mariner who lost vision in one eye must wait 6 months from the date of the vision loss before submitting any application.
“A mariner having lost vision in one eye must wait 6 months from the date of the vision loss before submitting any application”
Can the Coast Guard accept the Farnsworth D-15 Hue Test?
Yes, the Coast Guard will accept the Farnsworth D-15 Hue Test as a color vision test to meet the requirements of paragraph (b).
“The Coast Guard will accept Farnsworth D-15 Hue Test as a color vision test to meet the requirements of this paragraph.”
The text of 46 CFR 10.305
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Vision requirements
(a) Deck standard. (1) A mariner must have correctable vision to at least 20/40 in one eye and uncorrected vision of at least 20/200 in the same eye. The color sense must be determined to be satisfactory when tested by any of the following methods or an alternative test acceptable to the Coast Guard, without the use of color-sensing lenses:
(i) Pseudoisochromatic Plates (Dvorine, 2nd Edition; AOC; revised edition or AOC-HRR; Ishihara 14-, 24- , or 38-;plate editions).
(ii) Farnsworth Lantern.
(iii) Titmus Vision Tester/OPTEC 2000.
(iv) Optec 900.
(v) Richmond Test, 2nd and 4th edition.
(2) Applicants for an STCW endorsement must have correctable vision to at least 20/40 in both eyes and uncorrected vision of at least 20/200 in both eyes. A mariner who previously met these requirements and who suffers loss of vision in one eye after being issued an MMC is subject to the requirements of paragraphs (c), (d), and (e) of this section, as applicable. A mariner holding an MMC prior to January 1, 2017, must continue to meet the requirements of paragraph (a)(1) of this section.
(b) Engineering, Radio Officer, tank vessel endorsement, and MODU standard. A mariner must have correctable vision to at least 20/50 in one eye and uncorrected vision of at least 20/200 in the same eye and need only the ability to distinguish the colors red, green, blue, and yellow. The color sense must be determined to be satisfactory when tested by any color-vision test listed in paragraph (a) of this section, or an alternative test acceptable to the Coast Guard, without the use of color-sensing lenses. The Coast Guard will accept Farnsworth D-15 Hue Test as a color vision test to meet the requirements of this paragraph.
(c) Vision waiver. Any applicant whose uncorrected vision does not meet the 20/200 standard and is correctable to listed standards above may be granted a medical waiver in accordance with § 10.303. If a vision waiver is granted, a limitation will be placed on the medical certificate indicating the mariner may not serve under the authority of the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel. Waivers are not normally granted to an applicant whose corrected vision in the better eye is not at least 20/40 for deck officers or 20/50 for engineer officers.
(d) Vision operational limitation. If corrective lenses are required in order to meet the vision standards above, a mariner may not serve under the authority of the endorsement unless corrective lenses are worn and spare lenses are carried onboard a vessel. This operational limitation will be placed on their medical certificate.
(e) Loss of vision. A mariner having lost vision in one eye must wait 6 months from the date of the vision loss before submitting any application, and must provide a statement of demonstrated ability on their medical examination.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.