Definition of Cataract

Cataracts occur when the lens of the eye becomes cloudy and normal vision is impaired. There are many causes of cataracts including (but not limited to) cortisone medication, trauma, diabetes, and aging. The symptoms of cataracts include double or blurred vision and unusual sensitivity to light and glare.

See MedlinePlus® - Health Topics - Cataract for more information.

Introduction

Over the years, the growth of cataract surgery rates has been remarkable. Previously requiring strict bed rest for several days and thick distorting glasses that limited patient's mobility, technological improvements have made it possible to perform cataract surgery quickly and safely on an outpatient basis. Lens replacement allows vast improvements in vision, hence in quality of life. The volume of cataract surgery increased 32% in Manitoba from 1992/93-1996/97, with the rate increasing 27% (De Coster et al. 1998).

Two related methods have been used at MCHP to define cataract surgery: the earliest using tariff codes from the medical services/physician claims data, and more recently using tariff codes from the medical services data and procedure codes from the hospital discharge abstracts data. Generally, only Manitoba residents are included in analyses. These individuals have been assigned by 'R' postal codes but users should review the Residents of Manitoba concept.

1. Tariff Codes Only

The first method uses only tariff codes from the medical services/physician claims data to identify cataract surgery in Manitoba. This method was used in the WRHA (Frohlich 2000) , RHA (Black 1999) , and Downsizing (Brownell 1999) deliverables.

Codes used to identify cataract surgeries in Manitoba:

• Tariff codes: 5611, 5612
  
• The following real hospital numbers identify surgeries done in clinics: missing, 16, 17, 20, 23, 24, 25, 29, 32.
  
• Hospital numbers for out-of-province MDs are assigned a missing value before clinics are identified.

Work has also been done using the reciprocal medical claims to identify the procedures done in the Gimble Clinic, Alberta (Brownell 1999) . This analysis allows us to capture further surgeries done on Manitoba registered patients in other provinces (Alberta). The numbers represented are quite small in more recent years and generally not used in most MCHP research.

Codes used to identify cataract surgeries in Alberta:
• Host tariff codes: 2772, 27.72.
  
• Gimble Clinic identified using remote MD number 679236800

2. Tariff Codes and Procedure Codes

The second method uses tariff codes from the medical services/physician claims data and procedure codes in hospital discharge abstracts data to identify cataract surgery in Manitoba. This method was used in the Waiting Times (2000) , the Manitoba RHA Indicators Atlas (2009) , and the Profile of Metis Health Status and Healthcare Utilization in Manitoba (2010) deliverables. The methods used in these studies are described below.

A. De Coster et al. (2000)

The method of using tariff codes and procedures codes to identify cataract surgery in Manitoba was employed in the Waiting Times deliverable ( De Coster (2000) ). While more complicated, it likely gives a better indication of the separation for surgeries done in hospital and those done in clinics. De Coster noted (personal communication) that the addition of the hospital data does not provide any more surgeries but does allow the researcher to separate private and public clinics.

The identification of cataract surgery was done in a three-step process:


1. Medical Services/Physician Claims
   
   Identify cataract surgeries as above. In the waiting time study the following exclusions were made:
   • all out of province hospitals are removed,
     
   • all out of province MDs removed,
     
   • all non-clinic claims removed (i.e. remove all hospital cataract surgeries),
     
   • any individuals that had a cataract surgery within the three years (1991/92-1993/94) prior to the study were also removed.
   
   
2. Hospital discharge abstracts
   
   Procedure codes used to identify cataract surgery:
   
   • 13.11, 13.19, 13.41, 13.42, 13.51, 13.59, 13.2-13.29, 13.3-13.39.
   
   In the waiting time study the following exclusions were made:
   • All out of province hospitals are removed,
     
   • Non-surgical outpatients as defined using DRG are removed,
     
   • any individuals that had a cataract surgery within the three years (1991/92-1993/94) prior to the study.
   
   Along with these exclusions the waiting time study only used the first procedure code to identify cataract surgery. This means that any separations where the cataract surgery was not the primary procedure would not be included. The exclusion of non-surgical outpatients may also exclude some separations where cataract surgery was performed (see the Surgical/Medical Outpatient Identification concept for more information).
   
   
3. Combine Physician and Hospital data
   
   After combining the physician and hospital data any physician records where the service date is included within the period of the hospital stay are excluded. In the waiting time study only the first record found for each individual was retained based on PHIN/service date and only clinics and surgical outpatient (elective or day care) are retained.

SAS code for the cataract surgery identification method used in De Coster et al. (2000) is available in the SAS code and formats (internal access only) section below.

B. Fransoo et al. (2009), Martens et al. (2010), Chartier et al. (2012), Fransoo et al. (2013), and Fransoo et al. (2019)

The same method of identifying cataract surgery was employed in the following reports:


• Manitoba RHA Indicators Atlas 2009 by Fransoo et al. (2009);
  
• Profile of Metis Health Status and Healthcare Utilization in Manitoba by Martens et al. (2010);
  
• Health and Healthcare Utilization of Francophones in Manitoba by Chartier et al. (2012);
  
• The 2013 RHA Indicators Atlas by Fransoo et al. (2013); ; and
  
• The 2019 RHA Indicators Atlas by Fransoo et al. (2019)

Cataract surgery was defined by either:


• a physician claim with physician tariff codes 5611 or 5612 and tariff prefix 2 (surgery), or
  
• from a hospital discharge abstract with any one of the following ICD-9-CM procedure codes: 13.11, 13.19, 13.2, 13.3, 13.41, 13.42, 13.43, 13.51 or 13.59 or a CCI (Canadian Classification of Health Interventions) code of 1.CL.89 recorded in any procedure field in the abstract for residents age 50 or older.

Only one surgery per person per day is counted to reduce duplicates. Further, if the physician claim for the cataract surgery falls within the date of admission and separation to hospital for a cataract surgery, only one surgery will be counted.

Out of Province Tariff Codes

In the reports above, additional cataract surgeries performed out-of-province for Manitoba residents were added from medical reciprocal claims (out-of-province), including Alberta (tariff code 27.72) and Saskatchewan (tariff codes 135S, 136S, 226S and 325S).

Further Information

For more information, see:


• section 8.6 Cataract Surgery in Manitoba RHA Indicators Atlas 2009 by Fransoo et al. (2009)
  
• section 11.5 Cataract Surgery Rates in Profile of Metis Health Status and Healthcare Utilization in Manitoba by Martens et al. (2010)
  
• section 11.6 Cataract Surgery in Health and Healthcare Utilization of Francophones in Manitoba by Chartier et al. (2012)
  
• section 8.6 Cataract Surgery in The 2013 RHA Indicators Atlas by Fransoo et al. (2013)
  
• section 8.6 Cataract Surgery Rates in The 2019 RHA Indicators Atlas by Fransoo et al. (2019)