Monday, December 21, 2020


One of the leading causes of blindness in older individuals is glaucoma, so in this edition of “In the kNOW”, we’ll discuss coding for this serious condition.  First, however, let’s get a better understanding of the disease.  In glaucoma, the optic nerve is damaged which results in loss of vision.  This is often the result of increased pressure within the eye due to a buildup of aqueous humor.  The increase in fluid could be a result of poor drainage through the trabecular meshwork or overproduction.  The loss of vision that occurs with glaucoma is irreparable, and there is no cure for glaucoma.  However, early diagnosis of the condition can help prevent or minimize vision loss.  This is one reason why regular ophthalmologic appointments are so important as the vision loss with glaucoma can be insidious, worsening slowly without the patient realizing there is a problem.  Without proper treatment, blindness will result from glaucoma. 

ICD-10-CM addresses glaucoma in the Official Coding Guidelines.  The first guideline related to glaucoma focuses on the fact that there are many types of glaucoma (low-tension, open-angle, angle-closure, etc.), and that to accurately reflect the patient’s condition, coding professionals should assign as many codes from the H40 category as necessary to convey the patient’s diagnosis.  The codes in the H40 category capture the type and stage of the glaucoma, along with the affected eye.

The next guideline revolves around coding for bilateral glaucoma.  When the type and stage of the glaucoma is the same in both eyes, if there is a code for “bilateral”, then that is the code that should be assigned.  However, in the circumstance that the type and stage of the glaucoma are the same in both eyes, but there is no code that reflects “bilateral”, (for example, in subcategories H40.10 and H40.20), then coding professionals are instructed to assign only ONE code.  In both circumstances noted here, the seventh character assigned will indicate the stage of the glaucoma.

Bilateral glaucoma coding continues to be addressed in the third guideline.  While the second guideline dealt with same type and stage of glaucoma, this guideline addresses coding when there is bilateral glaucoma but with different type or stage.  When such is the case, a code should be assigned for each eye based on glaucoma type and stage for the specific eye.  When coding bilateral glaucoma of different types, if laterality is not distinguished in the code (for example, in subcategories H40.10 and H40.20), coding professionals are required to assign one code for EACH type of glaucoma using the seventh character to reflect the stage.  When coding bilateral glaucoma of different stages but the same type, if laterality is not distinguished in the code (for example, in subcategories H40.10 and H40.20), the instruction is to assign a code for the type of glaucoma for each eye using the appropriate seventh character to capture the stage.

The fourth glaucoma guideline provides instruction on how to code glaucoma for an inpatient whose condition has worsened during their stay.  In this instance, the glaucoma code assigned should reflect the highest stage that was documented during the admission.

The final guideline related to glaucoma provides clarification on the term “indeterminate” stage.  Coding “indeterminate” stage for glaucoma means that clinical determination of the glaucoma stage cannot be made by the provider.  It is important for coding professionals to be mindful of the distinction between “indeterminate” and “unspecified” stages.  “Unspecified” is assigned for a glaucoma stage only when there is no documentation at all regarding the glaucoma stage.   

Review of the guidelines will enable coding professionals to correctly apply codes for glaucoma conditions.

you are In the kNOW!!

About the Author 

Dianna Foley, RHIA, CHPS, CCS  is OHIMA's Coding Education Coordinator. Dianna has been an HIM professional for 20 years. She progressed through the ranks of coder, department supervisor, and department director, to her current role as a coding consultant. 

She recently served as the program director for Medical Coding and HIT at Eastern Gateway Community College. Dianna earned her bachelor's degree from the University of Cincinnati subsequently achieving her RHIA, CHPS, and CCS certifications. She is an AHIMA Approved ICD-10-CM/PCS Trainer and a a presenter at regional HIM meetings and the OHIMA Annual Meeting.