Effect of disinsertion of rectus eye muscles on aqueous humor composition in rabbits

To evaluate aqueous humor composition and biochemical analysis in a rabbit model for anterior segment ischemia.

Six rabbits underwent bilateral disinsertion of the four rectus eye muscles. One day later, aqueous humor (0.1 to 0.2 mL) was withdrawn from the anterior chamber and the concentrations of electrolytes, glucose, and lactate were determined. Similar assessments were performed in 8 eyes of 4 control rabbits that were not operated on.

Sodium and calcium concentrations (mean +/- standard deviation) were significantly higher in the study group than in the control group (142 +/- 2.9 vs 138 +/- 2 mmol/L, P = .002, and 1.4 +/- 0.1 vs 1.3 +/- 0 mmol/L, P = .005, respectively). Potassium concentrations were significantly lower in the study group than in the control group (4.1 +/- 0.5 vs 4.5 +/- 0.1 mmol/L; P = .02). The mean glucose level in the study group was 108.4 mg/dL, which is comparable to the published normal value of 108 mg/dL, and the mean lactate level was 124 mg/dL, which is significantly higher than the published normal value of 78 mg/dL (P = .001).

Bilateral disinsertion of the four rectus muscles in rabbits resulted in a breakdown of the blood-aqueous barrier, as reflected and measured by an electrolyte imbalance. These experimental results may be useful in the future in searching for methods of manipulating the ischemic response. There is currently no indication to perform anterior chamber taps in humans for that purpose.