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Increased Risk of Diabetic Retinopathy Due to Cataract Surgery

Jun 26, 2021
 
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Olivia Shenouda, PharmD. Candidate, Florida A&M University School of Pharmacy

Better management of diabetes and dyslipidemia could reduce cataract risk, and thus perhaps retinopathy risk as well. 

Due to its profound effect on middle-aged adults, evaluating risk factors for diabetic retinopathy to focus on prevention and control is an important socioeconomic and health issue. The risk factors of diabetic retinopathy include the duration of diabetes, early age of onset of diabetes, presence of neuropathy, and hypertension, cholesterol, and glycated hemoglobin A1C (HbA1C). In addition to these general factors, the surgery of cataracts has also been included as an essential risk factor associated with diabetic retinopathy progression. 

 

Although surgery is a typical response to cataracts, there is little understanding of the link between cataract surgery and the increased risk of diabetic retinopathy (DR). The Singapore National Eye Center assesses the risk of cataract surgery in patients with type 2 diabetes mellitus. Currently, cataracts and diabetic retinopathy are the leading cause of worldwide blindness. If extraction is a standard cataract treatment, individuals with this type of diabetes are at increased risk of developing diabetic retinopathy. Patients with diabetic retinopathy also have the risk of developing cataracts. 

In a population-based group, researchers surveyed patients admitted to the Singapore Eye Disease Epidemiology Study. The researchers examined a total of 1,734 eyes from 972 people with diabetes. Each patient participated in a baseline visit between June 2004 and March 2009, with a 6-year follow-up visit between June 2011 and July 2016. Eyes with incidence of DR at follow-up were defined as those with the presence of any DR (level ≥15 based on the modified Airlie House classification system, graded from retinal photographs), without diabetic retinopathy at baseline. 

They evaluated the links between cataracts and the likelihood of diabetic retinopathy using a Poisson regression model with a generalized estimating equation for correlation between both eyes. 

A total of 163 eyes in the study had already undergone a cataract surgery at the beginning of the study, and 187 eyes underwent cataract surgery at any time during the follow-up. Of the 350 eyes from individuals who underwent cataract surgery, 77 (22.0%) developed diabetic retinopathy. 

Of the 1384 patients’ eyes that never underwent cataract surgery and never had cataracts, 195 patients developed diabetic retinopathy (14.1%). 

The researchers of this study accounted for the change in age, sex, ethnicity, A1c level, duration of diabetes, blood glucose level, the use of anti-diabetic medication, the use of antihypertensives, body mass index, and smoking status; it was found from the use regression analysis that any prior cataract surgery increased the risk of diabetic retinopathy significantly.  

This retrospective cohort study shows that the performance of previous cataract surgery was linked to a higher risk of developing diabetic retinopathy in people with diabetes. However, further confirmation is needed to prove this association; the authors included recent meta-analysis studies showing that increasing physical activity and exercise can help prevent age-related cataracts. Using data from half a dozen studies, a team of researchers found that increased physical activity was associated with a 10% lower risk of developing age-related cataracts in later life. 

The results of multiple studies revealed that dyslipidemia is still the most common risk factor for cataract formation. Researchers found that total cholesterol is lower in cataract patients. In a cohort study, diabetes and dyslipidemia were independently related to a higher incidence of cataract formation; the results were similar to those of a later study. In a recent study, researchers found low high-density lipoprotein to be linked with cataracts. These findings point out that dyslipidemia and diabetes should be considered risk factors for cataract formation and cataracts, either together or alone. To prove the findings, another study was done to confirm that the use of statins significantly lowered the risk for cataracts. 

Practice Pearls: 

  • Previous cataract surgery was linked to higher risk of diabetic retinopathy. 
  • Diabetes and dyslipidemia should be considered risk factors for cataracts. 
  • Controlling A1C would lower the risk of cataracts in patients with diabetes.  
  • The use of statins will indirectly reduce the risk of cataracts. 

 

 

Tham YC et.al. “Association of Cataract Surgery With Risk of Diabetic Retinopathy Among Asian Participants in the Singapore Epidemiology of Eye Diseases Study.” JAMA, June 16, 2020. 

Walter, Kenny. “Cataract Surgery Increases Risk of Diabetic Retinopathy.” HCPLive®, July 20, 2020.  

 

Olivia Shenouda, Fourth-year Doctor of Pharmacy Candidate, Florida A&M University