Prior authorization is a health plan's approval, obtained before a service is delivered, confirming the plan considers the care medically necessary and agrees to cover it. Without that approval on file, the plan can deny the claim even when the care was clinically appropriate and correctly coded.
It is also called preauthorization, pre-authorization, prior auth, precertification or prior approval. Payers use the terms interchangeably and so does most of the industry. There is no meaningful difference between them, which is covered in full further down.
KEY TAKEAWAY
Prior authorization is the plan saying yes before the service happens. Skip it, and a perfectly valid claim can still be denied.
Prior Authorization in Optometry and Eye Care
Eye care sits across two coverage systems, and which one a visit belongs to decides whether authorization is even a question.
Prior authorization is a medical plan concept. Routine vision plan services run on a different model, usually an eligibility check and an authorization number issued at the point of service rather than a medical necessity review. So the first thing that determines the authorization path is not the procedure. It is the medical versus vision routing decision made at intake, and that decision follows from the reason the patient came in.
A patient booked for new glasses and a patient who came in because something feels wrong with the eye are two different visits. The second one may route to the medical plan, where authorization rules apply, imaging may need approval, and drugs such as anti-VEGF injections almost certainly will.
The vision plan side is less consistent than practices expect. Davis Vision's provider manual states that a limited number of its clients allow optometrists to bill Davis Vision for non-routine medical eye services, that Davis Vision does not pre-authorize those services, and that they may be subject to retrospective review. So on that plan there is no approval available before the visit and the decision can arrive after the care has been delivered.
Confirming authorization requirements during insurance benefit verification, and again when coordinating primary and secondary plans, is what stops these becoming denials. The wider picture of how the front end drives reimbursement is in the optometry billing guide.
Key insight:
In eye care the authorization question is downstream of the routing question. Get the plan wrong at check in and the entire authorization path was wrong before anybody looked up a requirement.
How Prior Authorization Works
The process runs before the visit or procedure, not after.
The practice identifies that a service requires authorization, submits a request to the payer with supporting clinical documentation, and waits for a determination. The payer reviews the request against its medical necessity criteria and approves it, denies it, or asks for more information. An approval comes with an authorization number, and that number has to be attached to the claim when it is billed.
Deliver the service before the approval comes back and the practice is carrying the risk that the claim will not be paid.
Key insight:
The authorization number is part of the claim, not a separate record. If it is not attached when the claim goes out, the approval may as well not exist.
Preauthorization vs Prior Authorization: Is There a Difference?
No. Preauthorization, pre-authorization, prior authorization, prior auth and prior approval all describe the same thing, which is a payer approving a service before it is delivered. Different payers simply chose different words for it, and a single plan document will often use two of them on the same page.
Precertification is usually the same thing as well, though a few payers use it more narrowly for inpatient admissions and reserve prior authorization for outpatient services. If a payer's manual distinguishes the two, that manual governs.
What is genuinely different is a referral, and that distinction matters. A referral is a primary care provider directing a patient to a specialist. Prior authorization is a plan approving a service. A visit can require one, both, or neither.
Key insight:
The word is not the variable. What varies is which payer requires approval for which service, and that is a plan level question every time.
Which Services Typically Require Prior Authorization
Requirements vary by payer and by plan within the same payer. Authorization is commonly required for advanced imaging, many surgical procedures, certain specialty and high cost medications, durable medical equipment, and some diagnostic testing. Routine office visits usually do not require it.
Two patients holding cards from the same insurer can have different rules, because the requirement sits with the employer group's plan design rather than with the insurer's brand. The only reliable way to know is to check that specific patient's plan during eligibility verification, before the visit.
Key insight:
The requirement belongs to the employer group's plan design, not to the insurer's name on the card, which is why two patients with identical cards can have different answers.
Prior Authorization for Medication
Medication authorization is the part most often misunderstood right now, and the reason is a detail in the 2026 federal rule.
The CMS Interoperability and Prior Authorization Final Rule, CMS-0057-F, sets decision deadlines and denial explanation requirements for impacted payers. Drugs are excluded from that rule. Every reference to prior authorization in CMS-0057-F is to authorizations other than those for drugs.
So a Medicare Advantage plan owes a decision on a standard medical service request within seven calendar days. The same plan's decision on a prescription drug request runs on the separate Part D coverage determination rules and their own timeframes, not on the CMS-0057-F clock.
In eye care this is not academic. Anti-VEGF injections and other pharmacological treatments are frequently the services where authorization is required, so the category most likely to need approval is the category the new deadlines do not cover.
Key insight:
If a practice assumes the 2026 timeframes apply to a drug authorization, it will plan around a deadline the payer does not owe.
How Long Does Prior Authorization Take?
Since 1 January 2026, impacted payers must decide expedited requests within 72 hours and standard requests within seven calendar days, and must give a specific reason when they deny.
The list of impacted payers is complete, not illustrative. It is Medicare Advantage organizations, state Medicaid and CHIP fee for service programs, Medicaid managed care plans, CHIP managed care entities, and Qualified Health Plan issuers on the federally facilitated exchanges. Drugs are excluded throughout.
Read that list once more and note who is absent from it.
Standalone vision plans are not on it. VSP, EyeMed, Davis Vision and Superior Vision carry no decision deadline under this rule, no obligation to give a specific denial reason under it, and no API requirement in 2027. They continue to operate under the terms in their own provider manuals.
Commercial plans outside the impacted list also set their own timelines, which run from same day to a couple of weeks.
Key insight:
For a practice billing both medical and vision, half the payer mix is now on a federal clock and the other half is not. That gap is new and it widens in 2027.
Prior Authorization and Claim Denials
A missing or invalid authorization is one of the most common denial reasons and one of the few that is almost entirely preventable, because the requirement is knowable before the service rather than after it.
The cost is not the correction. It is that the care has already been delivered by the time the denial arrives, so the practice is appealing or absorbing a loss it could have avoided at intake. Depending on the payer contract, it may not be able to bill the patient for the difference either.
This is why authorization belongs to the front desk and the eligibility check rather than to the billing team weeks later.
The timing problem compounds on the vision side. Davis Vision requires claims to be submitted within sixty days of the date services were provided, and that window runs from the date of service rather than from the date a denial arrives. A claim that went to the wrong plan first reaches the correct one with part of its filing window already spent.
KEY TAKEAWAY
A no authorization denial is cheap to prevent and expensive to receive, because by the time it arrives the practice has already spent the chair time, the staff time and the materials.
What Changed in 2026 and What Changes in 2027
Prior authorization is midway through the largest reform cycle it has had, and it is running on two tracks at once. One is a federal rule. The other is a voluntary industry pledge. They are frequently confused and they are not the same thing.
Start with the federal rule. CMS-0057-F was finalised in January 2024. From 1 January 2026 impacted payers must meet the 72 hour and seven calendar day decision deadlines, provide a specific reason for a denial, and publish prior authorization metrics on their websites annually.
By 1 January 2027 those same payers must implement four APIs: Patient Access, Provider Access, Payer to Payer, and a Prior Authorization API. The last of these is the one that changes daily work, because it allows a practice's system to ask what is required, submit the request, and check status without a portal login or a fax.
The second track is the industry pledge. In June 2025, AHIP announced that more than forty health insurance organizations, covering around 257 million Americans, had committed to six changes. Standardised electronic prior authorization using FHIR APIs by 1 January 2027. Specific reductions in the scope of medical prior authorization by 1 January 2026. Honouring existing authorizations for ninety days when a patient changes plans. Clearer explanations of determinations. At least eighty percent of electronic authorization approvals answered in real time by 2027. And continued review of clinical denials by medical professionals.
On 7 April 2026, AHIP and the Blue Cross Blue Shield Association reported that insurers had cut prior authorization requirements by about eleven percent over the preceding ten months, roughly 6.5 million fewer authorization requests, with Medicare Advantage down by more than fifteen percent.
Worth being precise about what that pledge is and is not. It is voluntary, it is not enforceable the way a rule is, and it names no specific procedures. Reductions are committed to at the level of each individual plan rather than as a common list.
Key insight:
Requirements are falling and answers are getting faster, on the medical side, for payers on the impacted list. Nothing in either track reaches standalone vision plans, so the practices seeing the least benefit are the ones billing both.
The next step: decide the plan before the authorization
Authorization requirements are a property of the plan a visit belongs to, so the routing call at check in decides the whole path.
Sources
CMS Interoperability and Prior Authorization Final Rule, CMS-0057-F, finalised January 2024, CMS fact sheet. AHIP announcement of health plan prior authorization commitments, June 2025. AHIP and Blue Cross Blue Shield Association progress announcement, 7 April 2026. Davis Vision provider manual. Optometric Management, September 2025, on CPT 92015 coverage.
Frequently Asked Questions
Is prior authorization the same as preauthorization?
Yes. Preauthorization, pre-authorization, prior authorization, prior auth and prior approval all describe a payer approving a service before it is delivered. Payers use the terms interchangeably. Precertification usually means the same thing, though a few payers reserve it for inpatient admissions.
Is prior authorization the same as a referral?
No. A referral is a primary care provider directing a patient to a specialist. Prior authorization is a health plan approving a specific service before it is delivered. A visit can require one, both, or neither.
What happens if you skip prior authorization?
The claim is likely to be denied, and depending on the payer contract the practice may not be able to bill the patient for the difference. Some payers allow a retroactive authorization in limited circumstances. It is not guaranteed and it is not something to plan around.
Does prior authorization guarantee payment?
No. Authorization confirms medical necessity. Payment still depends on the patient's eligibility on the date of service, active coverage, correct coding and timely filing. An authorized service can still be denied for a different reason.
Do the 2026 CMS deadlines apply to medication prior authorization?
No. Drugs are excluded from CMS-0057-F. The 72 hour and seven calendar day deadlines cover authorizations other than those for drugs. Prescription drug requests run on their own separate rules and timeframes.
Do vision plans require prior authorization?
Vision plans generally use an eligibility and authorization model rather than a medical necessity review, and they are not covered by CMS-0057-F. Davis Vision's provider manual states it does not pre-authorize medical optometry services and that those services may be subject to retrospective review. Whether authorization applies usually comes down to whether the visit is billed to the medical plan or the vision plan, which is decided at intake.
Which payers have to meet the 2026 decision deadlines?
Medicare Advantage organizations, state Medicaid and CHIP fee for service programs, Medicaid managed care plans, CHIP managed care entities, and Qualified Health Plan issuers on the federally facilitated exchanges. That list is complete. Standalone vision plans and most commercial plans outside the exchanges are not included.