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Official Description

Ophthalmic ultrasound, diagnostic; corneal pachymetry, unilateral or bilateral (determination of corneal thickness)

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

Ophthalmic ultrasound, specifically for corneal pachymetry, is a diagnostic procedure that measures the thickness of the cornea, which is the transparent front part of the eye. This procedure can be performed on one eye (unilateral) or both eyes (bilateral). The technique is non-invasive and involves the use of an ultrasound probe that is placed directly onto the anesthetized central cornea. The ultrasound generates an ultra-high definition echogram, known as a corneal A-scan, which provides precise measurements of corneal thickness in micrometers. This method allows for the visualization of the corneal waveform, enabling healthcare professionals to superimpose multiple echograms to track changes in corneal thickness over time. Corneal pachymetry is particularly useful in diagnosing conditions such as bullous keratopathy and corneal edema, as well as in assessing the risk of glaucoma. Additionally, it plays a critical role in monitoring patients with Fuchs' endothelial dystrophy or posterior polymorphous dystrophy. The procedure is also valuable in evaluating patients before and after corneal refractive surgery, as well as in determining the rejection status following penetrating keratoplasty.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

Ophthalmic ultrasound for corneal pachymetry is indicated for several specific conditions and situations, including:

  • Bullous Keratopathy - A condition characterized by the formation of blisters on the cornea, leading to pain and vision impairment.
  • Corneal Edema - Swelling of the cornea that can result from various causes, including trauma or disease, affecting vision clarity.
  • Suspected Glaucoma - A condition that can lead to optic nerve damage and vision loss, where corneal thickness measurements can assist in risk assessment.
  • Monitoring Fuchs' Endothelial Dystrophy - A genetic condition that affects the corneal endothelium, leading to corneal swelling and vision issues.
  • Monitoring Posterior Polymorphous Dystrophy - A rare corneal dystrophy that can cause corneal swelling and vision problems, where pachymetry can help track disease progression.
  • Pre/Post Corneal Refractive Surgery Evaluation - Assessing corneal thickness before and after procedures such as LASIK to ensure safety and effectiveness.
  • Rejection Status Post Penetrating Keratoplasty - Evaluating corneal thickness to determine potential rejection of a transplanted cornea.

2. Procedure

The procedure for ophthalmic ultrasound corneal pachymetry involves several key steps to ensure accurate measurement of corneal thickness:

  • Preparation of the Patient - The patient is positioned comfortably, and the eye to be examined is prepared. An anesthetic drop is applied to the central cornea to minimize discomfort during the procedure.
  • Placement of the Ultrasound Probe - The ultrasound probe is gently placed directly onto the anesthetized central cornea. Care is taken to ensure proper alignment and contact to obtain accurate readings.
  • Acquisition of Echogram - The ultrasound device emits sound waves that penetrate the cornea and reflect back, creating an echogram. This echogram, known as a corneal A-scan, displays the corneal thickness in micrometers.
  • Analysis of Results - The obtained echogram is analyzed, allowing for the measurement of corneal thickness. The waveform can be compared to previous scans to monitor any changes over time.
  • Documentation - The results of the corneal pachymetry are documented in the patient's medical record, including any significant findings that may influence further management or treatment.

3. Post-Procedure

After the completion of the corneal pachymetry procedure, the patient may experience minimal discomfort, which typically resolves quickly due to the anesthetic used. There are generally no specific post-procedure care requirements, but patients are advised to avoid rubbing their eyes and to report any unusual symptoms, such as increased pain or vision changes, to their healthcare provider. Follow-up appointments may be scheduled to review the results and determine any necessary further evaluations or treatments based on the findings.

Short Descr ECHO EXAM OF EYE THICKNESS
Medium Descr OPHTHALMIC US DX CORNEAL PACHYMETRY UNI/BI
Long Descr Ophthalmic ultrasound, diagnostic; corneal pachymetry, unilateral or bilateral (determination of corneal thickness)
Status Code Active Code
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 1 - Diagnostic Tests for Radiology Services
Multiple Procedures (51) 7 - Special payment adjustment rules on the technical component (TC) of multiple diagnostic ophthalmology services apply...
Bilateral Surgery (50) 2 - 150% payment adjustment does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 0 - Payment restriction for assistants at surgery applies to this procedure...
Co-Surgeons (62) 0 - Co-surgeons not permitted for this procedure.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator STV-Packaged Codes
ASC Payment Indicator Packaged service/item; no separate payment made.
Type of Service (TOS) 4 - Diagnostic Radiology
Berenson-Eggers TOS (BETOS) M5C - Specialist - ophthalmology
MUE 1
CCS Clinical Classification 192 - Diagnostic ultrasound of head and neck
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
26 Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
TC Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles
GA Waiver of liability statement issued as required by payer policy, individual case
GC This service has been performed in part by a resident under the direction of a teaching physician
LT Left side (used to identify procedures performed on the left side of the body)
RT Right side (used to identify procedures performed on the right side of the body)
AQ Physician providing a service in an unlisted health professional shortage area (hpsa)
GW Service not related to the hospice patient's terminal condition
GZ Item or service expected to be denied as not reasonable and necessary
CC Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed)
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
XE Separate encounter, a service that is distinct because it occurred during a separate encounter
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
GY Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit
76 Repeat procedure or service by same physician or other qualified health care professional: it may be necessary to indicate that a procedure or service was repeated by the same physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 76 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
96 Habilitative services: when a service or procedure that may be either habilitative or rehabilitative in nature is provided for habilitative purposes, the physician or other qualified health care professional may add modifier 96 to the service or procedure code to indicate that the service or procedure provided was a habilitative service. habilitative services help an individual learn skills and functioning for daily living that the individual has not yet developed, and then keep and/or improve those learned skills. habilitative services also help an individual keep, learn, or improve skills and functioning for daily living.
Q6 Service furnished under a fee-for-time compensation arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
CR Catastrophe/disaster related
X2 Continuous/focused services: for reporting services by clinicians whose expertise is needed for the ongoing management of a chronic disease or a condition that needs to be managed and followed with no planned endpoint to the relationship; reporting clinician service examples include but are not limited to: a rheumatologist taking care of the patient's rheumatoid arthritis longitudinally but not providing general primary care services
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
25 Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service: it may be necessary to indicate that on the day a procedure or service identified by a cpt code was performed, the patient's condition required a significant, separately identifiable e/m service above and beyond the other service provided or beyond the usual preoperative and postoperative care associated with the procedure that was performed. a significant, separately identifiable e/m service is defined or substantiated by documentation that satisfies the relevant criteria for the respective e/m service to be reported (see evaluation and management services guidelines for instructions on determining level of e/m service). the e/m service may be prompted by the symptom or condition for which the procedure and/or service was provided. as such, different diagnoses are not required for reporting of the e/m services on the same date. this circumstance may be reported by adding modifier 25 to the appropriate level of e/m service. note: this modifier is not used to report an e/m service that resulted in a decision to perform surgery. see modifier 57 for significant, separately identifiable non-e/m services, see modifier 59.
50 Bilateral procedure: unless otherwise identified in the listings, bilateral procedures that are performed at the same session, should be identified by adding modifier 50 to the appropriate 5 digit code. note: this modifier should not be appended to designated "add-on" codes (see appendix d).
52 Reduced services: under certain circumstances a service or procedure is partially reduced or eliminated at the discretion of the physician or other qualified health care professional. under these circumstances the service provided can be identified by its usual procedure number and the addition of modifier 52, signifying that the service is reduced. this provides a means of reporting reduced services without disturbing the identification of the basic service. note: for hospital outpatient reporting of a previously scheduled procedure/service that is partially reduced or cancelled as a result of extenuating circumstances or those that threaten the well-being of the patient prior to or after administration of anesthesia, see modifiers 73 and 74 (see modifiers approved for asc hospital outpatient use).
55 Postoperative management only: when 1 physician or other qualified health care professional performed the postoperative management and another performed the surgical procedure, the postoperative component may be identified by adding modifier 55 to the usual procedure number.
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
77 Repeat procedure by another physician or other qualified health care professional: it may be necessary to indicate that a basic procedure or service was repeated by another physician or other qualified health care professional subsequent to the original procedure or service. this circumstance may be reported by adding modifier 77 to the repeated procedure or service. note: this modifier should not be appended to an e/m service.
AR Physician provider services in a physician scarcity area
E1 Upper left, eyelid
E4 Lower right, eyelid
GL Medically unnecessary upgrade provided instead of non-upgraded item, no charge, no advance beneficiary notice (abn)
GV Attending physician not employed or paid under arrangement by the patient's hospice provider
KX Requirements specified in the medical policy have been met
Q1 Routine clinical service provided in a clinical research study that is in an approved clinical research study
Q3 Live kidney donor surgery and related services
Q5 Service furnished under a reciprocal billing arrangement by a substitute physician or by a substitute physical therapist furnishing outpatient physical therapy services in a health professional shortage area, a medically underserved area, or a rural area
QJ Services/items provided to a prisoner or patient in state or local custody, however the state or local government, as applicable, meets the requirements in 42 cfr 411.4 (b)
T6 Right foot, second digit
Date
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Notes
2011-01-01 Changed Short description changed.
2005-01-01 Changed Code description changed.
2004-01-01 Added First appearance in code book in 2004.
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