Of all the requirements in a nondestructive testing (NDT) personnel program, the vision exam is the smallest and the easiest to lose. It takes five minutes, it costs almost nothing, and it falls due every year on a date nobody is watching. When it lapses, the certification can lapse with it, and nobody finds out until an auditor or a customer asks for the file.
This guide sets out what each of the main personnel schemes asks for in near vision and color, how often, who may give the test, and how to keep the annual clock from quietly suspending a technician.
Two tests, two clocks
Every scheme splits the vision requirement in two. Near-vision acuity checks that the technician can read fine print at reading distance, which is what matters for reading a scope display, a radiograph or a penetrant indication. Color perceptionchecks that they can tell apart the colors, or shades of gray, used in the method. Near vision is tested every year under the schemes reviewed here. Color is tested far less often, and one scheme tests it only once.
Distance vision is not part of any of them. A technician who needs glasses to drive may pass near vision without them, and one who reads a road sign perfectly may not.
The schemes side by side
| SNT-TC-1A (2024) | NAS410 (Rev 6) | NAVSEA T9074-AS-GIB-010/271 (Rev 1) | |
|---|---|---|---|
| Near-vision chart | Jaeger No. 2 or equivalent, not less than 12 in; Ortho-Rater 8 also acceptable | One of: Tumbling E (ISO 18490:2015); Snellen 20/25 at 16 in ± 1 in; Jaeger No. 1 at not less than 12 in | Jaeger J1 or equivalent, not less than 12 in and not more than 16 in |
| Eyes | At least one, natural or corrected | At least one, natural or corrected | One or both |
| Near-vision interval | Annually | Annually | Annually, or sooner after a condition affecting vision |
| Color | Initial certification, then every 5 years | At least every 5 years | Initial certification only, when the work requires it |
| Expiry | Last day of the month | End of the month | Last day of the month |
| Who gives it | Not specified; set it in the written practice | Trained personnel designated by the Responsible Level 3, or qualified medical personnel | A qualified technician using standard methods |
Our own summary of the editions listed at the end of this guide. Check each figure against your own copy and your written practice.
SNT-TC-1A: Jaeger No. 2, and no eye drops
The 2024 edition of SNT-TC-1A covers vision in paragraph 8.2. For near vision (8.2.1) it recommends that the technician read at least Jaeger No. 2, or equivalent type and size letter, at the distance the chart designates but not less than 12 inches, in at least one eye, with or without correction. An Ortho-Rater minimum of 8 or a similar test pattern is an accepted alternative. It should be given annually.
The 2024 edition added a restriction worth knowing: the near-vision paragraph now says correction means no pharmacological agents, and 8.2.1.1 adds, as a firm “shall” rather than a recommendation, that eye drops which improve acuity at any distance may not be used. ASNT's own summary of the edition notes that vision is under review by a technical advisory group and that more changes are expected, so watch the next edition. And 8.2.3 says vision exams expire on the last day of the month of expiration, the same month-end rule the edition applies to certifications.
Color is in 8.2.2: the technician should be able to distinguish and differentiate contrast among the colors or shades of gray used in the method, as the employer determines. It is recommended at initial certification and every five years after. The phrase “as determined by the employer” matters: a technician who cannot pass a general color plate test may still be able to do the colors a particular method uses, and the written practice should say how you decide.
Because SNT-TC-1A is a recommended practice, your written practice turns these recommendations into your rules, and 9.4.5 lists the current certification period's vision results among the records to keep. See the SNT-TC-1A guide for how the written practice works.
NAS410: three charts to choose from
NAS410 Revision 6 puts vision in 7.1.2 and Table 7, and this revision changed Table 7 to add the Tumbling E test of ISO 18490:2015. The near requirement can be met by any one of three options: Tumbling E to ISO 18490:2015, Snellen 20/25 at 16 inches plus or minus 1 inch, or Jaeger No. 1 at not less than 12 inches. The Snellen and Jaeger options are in at least one eye, natural or corrected, and the table rules out simulated tests and distances. Near vision is annual; color is at least every five years, and the requirement is that the technician can adequately distinguish the colors used in the process.
Several things in 7.1.2 go further than SNT-TC-1A:
- Who gives it. Snellen and Jaeger tests are given by trained personnel designated by the Responsible Level 3, or by qualified medical personnel. The designation is worth writing down.
- Correction worn on the job. If the technician needed correction to pass, they wear it for all testing and inspection.
- Color limitations. Any limitation in color perception is evaluated by the Responsible Level 3 before certification and approved in writing.
- Changes in vision. After any condition or procedure that could affect vision, the Responsible Level 3 is told and the technician is re-examined.
- Flow-down. The employer makes sure Table 7 reaches everyone it applies to, including outside facilities.
- Exemptions. The vision requirements do not apply to instructors or auditors.
The written practice has to name which acuity method the employer uses (4.1.5), and 7.1.1 requires the exam before first certification. The consequence of a lapse is explicit: 8.3.1 treats vision exams as expiring at the end of the month, and 8.3.2 lists an expired vision exam first among the reasons a certification is suspended. More in the NAS410 guide.
NAVSEA: J1, a distance window, and eye surgery
For Navy work, NAVSEA T9074-AS-GIB-010/271 Revision 1 sets its own vision rules in 1.6.7. Near vision is Jaeger J1 or equivalent at not less than 12 and not more than 16 inches, in one or both eyes. The test is annual, or sooner after a medical condition that may affect vision, such as eye surgery, and it has to be current at the time of certification examination. Color is tested only at initial certification and only when the work requires it, and the practical examination can serve as that test. Corrective aids used for the vision test must be used in the certification exam and in every inspection afterwards, and 1.6.8 asks for vision records noting any corrective aids to be kept for the current and preceding certification periods.
CP-189 and ISO 9712
Keeping the clock from biting
Vision lapses are almost never about eyesight. They are about dates. A few habits prevent most of them:
- Test to the strictest scheme you work under. If anyone on the roster does NAS410 or NAVSEA work, a Jaeger J1 test at a distance between 12 and 16 inches meets the near-vision line of all three schemes above in one sitting. Color still runs on each scheme's own cycle.
- Record the result, not a tick. Chart used, line read, distance, whether corrected, color result, who gave it and their designation. An auditor checking an NAS410 file needs to see that the tester was designated.
- Retest early. Expiry runs to the end of the month, so booking the test a few weeks before it falls due costs little and removes the risk of a suspended certification in the middle of a job.
- Watch for triggers. Eye surgery, an injury or a new prescription should prompt a retest under NAS410 and NAVSEA, whatever the calendar says.
- Keep medical detail apart. An optometrist's letter can carry more than the result. File the result where customers can see it and keep the rest restricted.
For the wider picture of certification dates, see tracking NDT certifications and NDT personnel standards compared.
How TRACE handles it
The People module records each vision exam as measured: near-vision acuity (J1, J2, 20/25), the chart used, whether it was corrected, and color perception. The expiry prefills a year out, your entered date always governs, and a reminder arrives before the technician goes out of currency. A Vision Exam form sits in each certification's paperwork, and documents attached to an exam upload restricted unless you untick the box.
Technicians see their own exams, and the portal of a client whose NDT program you run shows the dates, currency and result for its own technicians, never your working notes. The requirement itself comes from your written practice: TRACE tracks the cadence you set and does not decide what a standard asks of you.
Frequently asked questions
What near-vision test does SNT-TC-1A require?
The 2024 edition recommends that the candidate read at least Jaeger No. 2, or equivalent type and size, at the distance on the chart but not less than 12 inches, in at least one eye, natural or corrected. An Ortho-Rater minimum of 8 or a similar pattern is also acceptable. It should be given annually, and eye drops that improve acuity may not be used.
What near-vision test does NAS410 require?
NAS410 Revision 6 gives three options, of which one must be met: the Tumbling E test in accordance with ISO 18490:2015, Snellen 20/25 at 16 inches plus or minus 1 inch, or Jaeger No. 1 at not less than 12 inches, in at least one eye, natural or corrected. The near-vision test is annual, and the written practice has to name which method the employer uses.
How often is the color vision test required?
Under SNT-TC-1A (2024) at initial certification and every five years after. Under NAS410 Revision 6 at least every five years. NAVSEA T9074-AS-GIB-010/271 asks for it only at initial certification, and only when the work requires distinguishing colors.
What happens if a technician's vision exam expires?
Under NAS410 Revision 6 the certification is suspended until a current exam is on file. Under SNT-TC-1A, the employer's written practice sets the consequence, but an expired exam means the technician no longer meets the practice's vision requirement. All three documents reviewed here treat the exam as expiring at the end of the month it falls due.
Who can give an NDT vision exam?
NAS410 Revision 6 says the Snellen and Jaeger tests are given by trained personnel designated by the Responsible Level 3 or by qualified medical personnel. NAVSEA T9074-AS-GIB-010/271 says a qualified technician using standard methods. SNT-TC-1A (2024) does not say who, so the employer's written practice should.
Checked against
- ASNT SNT-TC-1A, 2024 edition, paragraphs 8.2 and 9.4.5, with the 2025 addendum
- NAS410 Revision 6, Aerospace Industries Association, revision date 1 December 2025: 4.1.5, 7.1.1, 7.1.2, Table 7, 8.3.1 and 8.3.2
- NAVSEA T9074-AS-GIB-010/271, Revision 1 (11 September 2014), 1.6.7 and 1.6.8
- ANSI/ASNT CP-189 and ISO 9712: not reviewed for this guide (described in outline only)
This guide summarises the documents above in our own words to help you find your way around them. It is not a substitute for them: requirements change between editions and contracts add their own, so check every figure against your own licensed copy and your written practice before you rely on it.
Named for reference only. TRACE is an independent product: it is not affiliated with, endorsed by, sponsored by or accredited by ASNT (publisher of SNT-TC-1A and CP-189), the Aerospace Industries Association (publisher of NAS410), ISO (publisher of ISO 18490 and ISO 9712) or NAVSEA (Naval Sea Systems Command, publisher of T9074-AS-GIB-010/271), or by any other organization whose standards or programs it describes. Their names and marks are their own.