As I wrote some weeks ago in the post APDC: Relevant conditions and scenarios that affects the eyes – Part 1 (this link will open in a new tab of your current browser window), in this new instalment post of coding diseases of the eye and adnexa, I shall discuss about cataracts affecting the lens, conditions affecting the choroid and retina, on to glaucoma characterised by damage of the optic nerve, and to end this post with some conditions affecting the vitreous body and globe and their appropriate coding.

ICD 10 has one (1) block ranging from codes H25-H28 for all disorders of lens within the Chapter VII Diseases of the eye and adnexa (H00-H59). Within this block, a Health Information Management (HIM) / Medical Records (MR) practitioner  will find four (4) sub-divisions (subcategories) of three (3) category categories of codes. The first sub-division H25 is for the single condition affecting the older population group – the senile cataract, three-character categories which I believe have been selected or grouped because of their frequency, severity or susceptibility to public health intervention.  The second, third and fourth sub-divisions i.e H26, H27 and H28 are grouped among diseases with some common characteristic as well as allowing many different but rarer conditions. As always there is a provision for ‘other’ conditions to be classified. Do take note that H25 to H27 each has a category for ‘unspecified’ conditions.

The results from the last known national eye survey conducted in 1996 to determine the prevalence of blindness and low vision and their major causes among the Malaysian population of all ages, cataract was the leading cause of blindness (39%) followed by retinal diseases (24%) and another result finding showed that uncorrected refractive errors (48%) and cataract (36%) were the major causes of low vision.

When coding cataracts in the young population, cataracts present at birth takes it place among the codes in the Chapter XVII Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99). Code H26.0 is only for cataracts diagnosed until later in life of new-borns namely infantile cataracts present early in life, but are not present at birth. Also take note that the subcategory for infantile and juvenile cataracts includes the descriptor presenile.

Cataracts caused by an underlying inflammatory disorder example cataract in chronic iridocyclitis are included in the category “Complicated cataract (H26.2)”.  Remember the option to use additional external cause code (Chapter XX), if desired, to identify drug in the case for drug-induced cataract or if desired, to identify cause in the case for traumatic cataract.

Two codes are required  for diabetic cataract, a special coding condition, whereby the coder has to go elsewhere to find the code for the underlying generalised disease and also report the code H28.0 since diabetic cataract is indeed a manifestation in a particular organ or site, in this case the eye and specifically the lens. This is the principle of the dagger and asterisk system which provides alternative classifications. Always code the primary code for the underlying disease which will be marked with a dagger (†) and code the optional additional code for the manifestation to be marked with an asterisk (*), in this case H28.0 The eye specialties everywhere normally have a desire to see diabetic cataract classified to the Chapter VII for this manifestation when it was the reason for medical care.

Now, for example when the diabetes is not identified as type 2? How do you code?

Rationally, I would code to E11.3 as the dagger code because of the following connection which is (i) you are directed from H28.0* – diabetic cataract to go to the block E10-E14 with common fourth character .3+, (ii) then I look up the block diabetes mellitus (E10-E14) from the Chapter IV Endocrine, nutritional and metabolic diseases (E00-E90), I find first “With ophthalmic complications, Diabetic: .3+, cataract (H28.0*) as among a list of fourth-character subdivisions for use with categories E10-E14 and type II, a inclusion term is listed below E11, and finally, (iii) since the coder is required to “See before E10 for subdivisions”. In summary, the asterisk code H28.0* leads me to find E11.3 from the above mentioned connection.

The category H33 lists codes regarding retinal detachments, when the retina is pulled or lifted away from its normal position. When there is a retinal break, detachment may or may not happen. Horseshoe tear, a type of retinal detachment with no retinal break is quite commonly reported and is given the code H33.3

What if you are presented with the main term “congenital macular degeneration” as the diagnosis? How will you find the correct code? You could look at congenital first, and you will be directed to find the condition. The condition is macular degeneration. Finding macular, you will locate degeneration (H35.3), and then to find hereditary (H35.5) at the second level.  This is the way your find your way in the Alphabetic Index forest of codes.

Glaucoma is another serious condition of the eye, actually it is a group of diseases of the eyes characterised by damage of the optic nerve which can lead to permanent damage to the optic nerve, loss of peripheral vision, and eventually, blindness. You may encounter some that are chronic and some that are acute while coding glaucoma.

In ICD 10, glaucoma that is described as congenital glaucoma is reported with a code from glaucoma described as childhood, infantile, juvenile, or congenital are all reported as congenital glaucoma with a code from Chapter XVII Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99) unlike in the past revision, ICD 9 when glaucoma that is described as childhood, infantile, or juvenile is reported with a code from the Chapter 6 – Nervous System and Sense Organ.

Glaucoma may be secondary to eye trauma,  eye inflammation, to other eye disorders and maybe even drugs. You may use the additional code, if desired, to identify cause or use the additional external cause code (Chapter XX), if desired, to identify drug.

You may not find any specific code for glaucoma associated with vascular disorders this time around in ICD 10, and the likely code to pick will be H40.8 Other glaucoma.

Endophthalmitis is to me the most common condition I had encountered for all conditions affecting the globe, affecting multiple structures of the eye, such as inflammation, degenerative conditions, and retained foreign bodies. Infact the inclusion clause “disorders affecting multiple structures of eye” included below H44 Disorders of globe already confirms this. By the way, endophthalmitis is an inflammatory condition within the intraocular cavities affecting the aqueous or vitreous humor. However, the ICD 10 does not differentiate between the terms acute, chronic, and unspecified endophthalmitis anymore but you can look up the Alphabetic Index and locate the qualifying terms like acute and subacute listed there under the lead term endophthalmitis, and the go find the appropriate code H44.0 Purulent endophthalmitis.

Coding vitreous haemorrhage in ICD 10 has changed, it now stands alone as H43.1, unlike in ICD 9.

Incidentally I have delayed writing this kind of posts as it required pulling together all my resources, understanding all the diseases and conditions in this Chapter, and finally a desirable post for the reader I wish to convince into reading a technical post like this one.

Readers, I think I have not more than three (3) more instalment posts on coding diseases of the eye and adnexa.

Happy coding!

References:

1. Gerard, JT & Bryan, D 2012, Principles of Anatomy & Physiology, 13th edn, John Wiley & Sons, Inc, New Jersey, USA
2. Michael, M & Valerie, OL 2012, Human anatomy, 3rd edn, The McGraw-Hill Companies, Inc., New York, USA
3. Phillip, T 2012, Seeley’s principles of anatomy & physiology, 2nd edn, The McGraw-Hill Companies, Inc., New York, USA
4. World Health Organization 2011, Volume 1 Tabular list, International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2010 edn, Geneva, Switzerland
5. Zainal, M, Ismail, SM, Ropilah, AR, Elias, H, Arumugam, G, Alias, G, Fathilah, J, Lim, TO, Ding, LM and Goh, PP 2002, Prevalence of blindness and low vision in Malaysian population: results from the National Eye Survey 1996, British Journal of Ophthalmology, September; 86(9): 951–956., viewed 27 Nov 2013, <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1771293/>