Most forecasting guides treat revenue as one number, which works fine if you sell one thing. An optometry practice sells two: exam services billed through insurance and optical products sold to patients at the chair. Those two streams have different margin structures and they arrive on different timelines. Running them through the same model is what makes the forecast wrong.

Why Optical and Clinical Revenue Don't Move Together

The optical side of your business is retail. A patient finishes their exam, chooses frames, places an order, and the revenue shows up within a day or two. What you earn from that transaction depends on your frame board pricing, your lab costs, and whether the patient buys at all. Back-to-school season, typically August and September, lifts optical volume for practices with a younger patient base. A quiet frame board in February does not necessarily mean the practice is struggling; it might just mean February.

Clinical exam revenue moves on a different schedule entirely. A patient has a comprehensive exam on a Tuesday. The claim goes to the payer later that week. The electronic remittance file comes back from the payer with an allowed amount that often differs from what was billed. Your billing manager posts that against the patient account and tracks what was denied, adjusted, or written off. That is their work, not your accountant's. The batch deposit hits your bank account 14 to 45 days after the exam, depending on your payer mix. An October exam might appear as a November bank deposit by the time everything clears.

Put those together and call the sum "monthly revenue" and you have a number that reflects different time periods for each component. October optical revenue plus September clinical collections, essentially, dressed up as a single figure.

What Makes the Problem Harder Than It Looks

A few things compound the timing mismatch.

Insurance reimbursement rates change, sometimes without much notice. Payer contracts get renegotiated. Medicare optometry reimbursements shift with annual CMS fee schedule updates, which have trended downward for several optometry exam codes over the past decade. If your clinical reimbursement per exam drops by $10 and you see 300 exams a month, that is $3,000 a month in revenue that disappears without a single patient leaving and without any change in how hard your staff is working. Exam volume holds steady. Revenue doesn't.

Optical revenue is constrained by what you stock. You cannot sell a frame that isn't on the board. Practices that let inventory age, or that run thin on styles patients actually want, lose optical revenue they could have captured. The loss never registers as a missed appointment. It shows up as a patient who glanced at the frame wall and ordered something elsewhere. That pattern is easy to miss if you're only watching exam counts.

Collection rate tells you more than volume. A practice seeing 800 patients a month might collect significantly less per doctor-day than one seeing 600, if denial rates are high or if write-offs are absorbing a large share of what was billed. Collections per doctor-day (total collected divided by the number of days a doctor was in the clinic) reflects what the practice actually earned per working day. That is the number worth tracking.

How to Build a Forecast That Is Actually Useful

The starting point is to separate the two streams before you try to combine them.

For the optical side: pull trailing 90-day optical product revenue, divide by patient encounters for the same period, and you have an average optical revenue per visit. That figure is your base rate. Apply it to your projected exam schedule. Adjust upward for back-to-school if your patient demographics support it, and double-check inventory turnover before doing so. If your average frame has been sitting for more than 12 months, the forecast is optimistic until you move the inventory.

For the clinical side: use 90-day collections per doctor-day, not billed charges. Apply it to your projected exam days over the forecast period. Then account for any payer contract changes you know are coming. This is also where you want to know your current denial rate. A practice collecting 88 cents for every dollar billed is in a different position than one collecting 72 cents, and the difference matters more than it sounds when you're projecting 90 days out.

Add the two projections together and you have a workable forward estimate. Not a perfect one, but one grounded in the actual revenue units of your business rather than a blended historical average that flattens meaningful differences between the two streams.

To make this concrete: a practice averaging $1,800 in optical revenue per 100 patient encounters (illustrative), with 400 projected encounters over the next 90 days, has roughly $7,200 in optical revenue to plan from. On the clinical side, if collections per doctor-day averaged $2,400 over the past three months and there are 45 doctor days scheduled in the next quarter, the clinical projection is around $108,000. Those two numbers, roughly $115,000 for the period, are a starting point. Not a guarantee, but a specific figure you can run a sensitivity test against, rather than a vague sense of "about what we usually do."

The KPI benchmarks article has more on how practices measure performance per doctor-day and what typical collection patterns look like across different practice types.

When a Simpler Approach Is Fine

A solo OD with stable exam volume, a consistent payer mix, and a frame board that moves predictably might not need two separate models. If your total collections per doctor-day is steady within a 5 percent band month over month, and your optical revenue follows the same seasonal rhythm each year, a 90-day rolling average of total collections gets you close enough for most decisions.

Complexity earns its place when you're growing, adding a second doctor, changing your insurance mix, or planning a capital purchase. Those decisions have larger consequences if the forecast is off by 20 percent. The two-stream model is not more work for its own sake. It gives you more useful signal when the stakes are higher.

The two-margins article goes deeper on how optical and clinical margins differ structurally and why treating them as one number creates blind spots in your monthly performance review.

Where the Accountant Fits Into This

Your billing manager handles your insurance claims and produces a collections report. Your accountant's work starts after the money lands in the bank: recording those batch deposits, tying the bank to the collections report, and translating everything into the monthly financial picture you plan from.

If you're looking at your numbers every six months, the collections data is already stale by the time you build a forecast. A monthly close cadence means the data from your billing manager feeds into clean financials within a few weeks, and the 90-day collections history you need for a useful forecast actually reflects what is happening in the practice now.

What you should see from that monthly report: optical revenue broken out from clinical, collections per doctor-day calculated (or calculable from the data), and any month where optical conversion ran low or where clinical collections dipped from the prior period flagged for discussion. If the monthly report your accountant produces does not give you enough data to run the forecast math described above, that is worth raising directly.

If you want a sense of what optometry practices at different revenue levels should be seeing from their key financial metrics each month, the KPI white paper available on our optometry practice page covers collections per doctor-day, optical margin, and the few other numbers that actually predict practice health over time.

Questions owners ask about this

Why is revenue forecasting harder for an optometry practice than for most small businesses?

Because you have two revenue streams that behave differently. Optical product sales are retail: they happen at the point of purchase and the margin is largely set by your frame board and lab costs. Clinical exam revenue runs through insurance payers, arrives days or weeks after the exam, and the reimbursement rate is determined by your payer contracts rather than by you. A forecasting model that treats these the same will be wrong in different directions at different times of year.

Should I forecast revenue from billed charges or from collections?

From collections. Billed charges are what you asked for. Between your submitted claim and the bank deposit sit the payer's allowed amount, any claim denials, coordination of benefits adjustments, and patient responsibility. Practices that forecast from billed charges routinely overestimate revenue by 20 to 35 percent depending on their payer mix (illustrative range; the gap is wider in high-Medicare, high-denial practices). Collections per doctor-day is the number that reflects what the practice actually earns.

Why does my optometry revenue fluctuate even when patient volume stays the same?

Usually because either your optical conversion or your clinical reimbursement rate shifted. Optical revenue depends on what patients buy, not just whether they show up. Clinical revenue depends on your payer mix and collection rate, which can change even if you see the same number of patients. Stable exam volume is a good sign, but it does not guarantee stable revenue. Tracking optical revenue per patient encounter and collections per doctor-day separately shows you which stream is causing the variance.

What is a reasonable gross margin for the optical side of an optometry practice?

A well-managed optical gross margin typically falls between 50 and 60 percent of optical product revenue, after subtracting frame costs, lens costs, and lab fees. Practices below 45 percent consistently often have frame board pricing that is too low, a lab arrangement that eats too much of the margin, or a contact lens segment with thin markups that drags the overall figure down. These are worth examining before attributing the shortfall to patient volume.

How far out can I realistically forecast optometry practice revenue?

Ninety days is reliably useful for most practices. You have three months of collections history, your exam schedule has some predictability, and any payer contract changes you know about can be factored in. Beyond 90 days, add a conservative scenario that models a 10 to 15 percent reduction in clinical reimbursement. Capital purchases and hiring decisions that survive both scenarios are ones you can execute confidently. Those that only survive the optimistic case warrant a harder look.