Health Information Management

Make sense of macular degeneration during Low Vision Awareness Month

Coding Educator, February 9, 2009

By Jennifer Avery, CCS, CPC, CPC-H CPC-I

As a coder we hear about all kinds of different disorders, diseases and syndromes but don’t always have time to really learn about them unless they could have some effect on a chart we are working on. For example, if we are we looking for complications and/or comorbid conditions to help us with our DRG assignment, we may have to do some research to determine whether signs or symptoms listed are a part of a condition, or if we should assign them separately. However, as a medical assistant I am always curious about how the disease works, what we can do to treat it, and what we can do to prevent it. I believe it is extremely important to learn this clinical information to be a better coder.

February is Low Vision Awareness Month, so I would like to take the opportunity to share a bit about macular degeneration (often abbreviated “AMD” or “ARMD” for “age-related macular degeneration”). AMD is a serious condition that currently affects around 1.75 million U.S. residents and that number is expected to climb to almost three million by the year 2020. And AMD is the leading cause of blindness in the United States in patients 65 and older. However, most coders don’t have the time to learn about it unless they work in a specialist’s office coding eye diseases and procedures or if they need to look into whether certain signs and symptoms are a part of AMD when working on a chart (e.g., when trying to meet medical necessity for the diagnostic tests performed on a particular patient).

AMD occurs due to a degeneration of the macula causing central vision loss. The macula is the part of the retina that is responsible for sharp, central vision necessary for reading or driving. There are two types of AMD: wet and dry.

The wet type (neovascular) occurs due to the formation of new blood vessels in an area where they are not supposed to be, mainly beneath the retina. Neovascularization is the body’s misguided way of trying to provide more nutrients and oxygen to the retina but instead, it creates scarring which leads to vision loss. This causes serious and permanent damage to the light-sensitive retinal cells, which die off and cause blind spots in the central vision field. The wet type of AMD occurs in about 10% of cases. It is also considered the most severe type as it leads to more serious vision loss.

There are two forms of wet macular degeneration: occult and classic. In the occult form, the blood vessels are less pronounced and the effects on the retina are not as severe. The classic form, often referred to as classic choroidal neovascularization, is the most severe form. When the blood vessels form, scarring occurs with very delineated outlines observed below the retina, which produces more severe vision loss.

Dry (nonneovascular) AMD is more common than wet and occurs in about 85–90% of all cases. Dry AMD is an early stage of the disease. It may result from aging and thinning of the macula or from deposits of pigmentation in the macula. In some cases it could be a combination of both.

Symptoms of AMD are shadowy areas in your central vision or unusual fuzziness or blurriness, or distorted vision. Typically, physicians detect AMD through a retinal exam before symptoms occur. When a physician suspects AMD he or she performs a simple test that measures central vision called the Amsler grid. When the physician detects a defect he or she may order a flourescein angiography to examine the retinal blood vessels surrounding the macula. Dry macular degeneration is diagnosed by yellowish spots called drusen that accumulate from deposits or debris from the deteriorating tissue around the macula.

Causes of AMD are linked to aging and eye tissue deterioration, as well as the presence of a variant gene known as complement factor H. The gene deficiency is associated with nearly half of all potentially blinding cases of AMD. It has also been linked to another gene, complement factor B, which may play a role in the body’s immune responses. Wet macular degeneration is believed to be caused by oxygen starved cells within the retina, which trigger a protein called vascular endothelial growth factor (VEGF) to activate neovascularization.

Studies have found several different (and occasionally contradictory) results as to the risk factors for AMD. Some of the most common preventable causes seem to include obesity and inactivity, hypertension, smoking and drug side effects. There are also risk factors that we cannot control, including aging, heredity, and light eye color. (Note that aging and smoking are the only two causes studies consistently find to be causes of AMD.)

Physicians may recommend wearing sunglasses with UV protection again the harmful effects of the sun and smoking cessation to prevent AMD. Taking higher doses of certain nutritional supplements (e.g., vitamins A, C, and E) may also prevent or slow down the progression of AMD.

Currently, there are no FDA-approved treatment options for the condition. Treatments focus more often on slowing the progression of AMD and possibly improving vision. Treatments may vary depending on the type and stage of AMD. For example, wet macular degeneration treatments target controlling neovascularization by giving anti-VEGF drugs (e.g., Lucentis, Macugen, and Visudyne) along with photodynamic thereapy. Treatment typically centers on the addition of nutritional supplements such as zinc, lutein, zeaxanthin, and vitamins A, C, and E.

Diagnostic coding options for macular degeneration depend on the documentation. Code 362.5x is for degeneration of macula and posterior pole unless it is described as hereditary degeneration. If hereditary, the ICD-9 Manual prompts you to report code 362.7x (Hereditary retinal dystrophies). For either subcategory code, the fifth digit further defines the type of degeneration. For example, dry macular degeneration codes to 362.51 while wet macular degeneration codes to 362.52.

In 2006 new codes were added to volume 3 of the ICD-9 Manual for procedures for the surgical implantation of an intraocular telescopic prosthesis, a miniature telescope for patients with moderate to profound visual impairment due to end stage age related macular degeneration. ICD-9 procedure code 13.91 identifies the implantation of the intraocular telescope prosthesis including the removal of any lens, any method. But coders shouldn’t use this code to represent secondary insertion (code 16.61) per the exclusion note.

Currently there are no category I CPT codes to represent the insertion of an intraocular implant without concurrent treatment of a cataract. In 2006, category III code 0001T was created to represent the insertion of a subconjunctival retinal prosthesis. Another category III code, 0124T was created for conjunctival incision with posterior placement of pharmacological agent (medication) to treat macular degeneration. However, the category III code doesn’t include medication, so coders should also report a HCPCS II code.

For the neovascularization forms of the disease, category III CPT code 0017T is used to identify the destruction of the macula drusen, as per the instructional note under CPT code 67220. This procedure involves the use of photocoagulation via laser. Due to the intensity of this procedure, it usually requires more than one treatment session. The description of code 67220 includes the multiple sessions.

CPT code 67221 describes photodynamic therapy, which involves the use of a low-energy targeted laser light to activate a photoactive drug administered intravenously to ablate abnormal tissue. The administration via intravenous infusion is included in the description of code 67221. Photodynamic therapy typically requires only one session.

CPT code 92240 identifies Indocyanine-green angiography with interpretation and report. This is a procedure used in diagnosing AMD.

There are not many relevant Official Coding Guidelines, leaving room for interpretation. Use the alphabetic indices in both your ICD-9 Manual and CPT Manual, as well as the parenthetical notes around the codes in each to assist with the coding of AMD. In addition, look for the development of additional category I CPT codes as the treatment options for AMD become more common.

Editor's note: Jennifer Avery, CCS, CPC, CPC-H CPC-I, is a regulatory specialist for HCPro, Inc. You can e-mail her at javery@hcpro.com.

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