The effect of the glycemic control on the aqueous humor glucose levels in diabetic patients undergoing elective cataract surgery

Abstract

Purpose: Aqueous humor glucose levels play a role in the anterior segment disorders’ pathophysiology, mainly in diabetics. Our purpose was to evaluate the ratio of aqueous humor glucose levels to blood glucose levels in diabetics and to evaluate the correlation between this ratio and blood glycated hemoglobin (HbA1c) levels. Methods: This prospective study was performed in Sheba Medical Center during 2016–2018. The study included type 2 diabetic patients admitted for elective cataract surgery. Blood glucose levels were measured immediately before surgery. HbA1c was obtained within 3 months preoperatively. At the beginning of surgery, 0.05–0.1 mL aqueous humor was drawn. Main outcome measures were aqueous humor glucose/blood glucose ratio and the correlation between HbA1c and aqueous humor glucose/blood glucose ratio. Results: Thirty-seven patients (mean age 75.2 ± 11.2 years) were recruited. The average aqueous humor glucose/blood glucose ratio was 0.69 ± 0.20. A significant positive correlation was found between aqueous humor and blood glucose levels, Pearson coefficient constant R = 0.63 (p < 0.01), and specifically stronger among older patients R = 0.89 (p < 0.01), females R = 0.74 (p < 0.01), patients with short-term disease (<10 years) R = 0.80 (p < 0.01), and patients treated with oral anti-diabetic treatment R = 0.74 (p < 0.01). A significant strong positive correlation was found between HbA1c levels and aqueous humor glucose/blood glucose ratio R = 0.62 (p < 0.01), and specifically stronger among older patients R = 0.82 (p < 0.01), males R = 0.70 (p < 0.01), patients with prolonged disease (⩾10 years) R = 0.540 (p < 0.05), and patients treated with oral anti-diabetic treatment R = 0.62 (p < 0.01). Conclusion: A significant strong correlation was found between aqueous humor glucose levels and blood glucose levels. Poor glycemic control was strongly correlated with an increased ratio, reflecting an increased anterior chamber’s glucose permeability. Older age group was found to have stronger correlation of poor glycemic control with this ratio.

Comparing the Rise in Glucose Concentration in Blood, Aqueous and Interstitial Fluid During a Glucose Tolerance Test

“… 36 Previous reports have shown a close correlation between glucose concentration in aqueous with the glucose concentration in blood in both humans and rabbits. 23 , 37 , 38 Likewise, the close correlation between interstitial fluid and blood has also been previously shown. 12 , 39 This study compared the time delay for the aqueous and interstitial fluid to respond to acute changes in blood glucose levels.…”

“… 40 , 41 , 43 Previous studies have shown a closer correlation of blood glucose with aqueous glucose concentrations in diabetic patients compared to nondiabetic individuals, which was attributed to a breakdown of the blood–ocular barrier in diabetics. 38 Ideally, CGM systems should show a change in the glucose concentration within 10 minutes after the blood glucose levels rise. 44 This can be achieved in interstitial fluid, and the results from this study have shown an equivalent response time in the aqueous of the anterior chamber and an even faster response in the posterior chamber of the eye.…”

Measurement of corneal biomechanical properties in diabetes mellitus using the Corvis ST

“…In the short-term effect of hyperglycemia, high aqueous humor glucose level is also reported. [50] On the other hand, HbA1c can reflect ECM (Extracellular matrix) remodeling such as collagen cross-linking in the long-term effect of hyperglycemia. Therefore, there may be inconsistent results in Tables 4 and 5.…”

Glucose levels between the anterior chamber of the eye and blood are correlated based on blood glucose dynamics

“…In addition, age population of the subjects was not deeply considered during the study. A previous study reported that the stronger positive correlation ratio could be seen in older patients [ 30 ]. This matter could also be solved when more subjects are recruited for the study.…”