Abstract
Purpose: :
To study the use of standardized Seidel’s test for the evaluation of different configurations of clear corneal incisions at different intraocular pressures (IOP), and to analyze its value at predicting extra ocular inflow of bacterial-sized particles of India ink.
Methods: :
Seven fresh human eyes (Tissue Banks International, Baltimore, MD) were used in the study. Two 27-gauge needles connected to a saline solution bag and a digital manometer were inserted through the limbus 120 degrees apart from each other. Three different incisions of 2.75 mm width were performed in different quadrants of each cornea in the following fashion: A) 2-step 3.0 mm tunnel length, B) uniplanar tunnel of 1.5 mm, and C) uniplanar tunnel of 3.0 mm in length. Seidel’s test was evaluated at five different stable IOPs controlled by manometry at 5, 10, 20, 40, and 50 mmHg. Tests were recorded by a blind observer in a semiquantitative scale from 0 (negative) to 3 (markedly positive). In parallel, India ink was applied to the incision site and IOP fluctuation was induced by applying pressure to the limbal area of the opposite quadrant, leaving an IOP of ~10 mmHg in the eye. India ink influx into the incisions was outlined and measured by planimetry.
Results: :
Seidel’s test scores were significantly lower in the C group when compared to the B group at all IOPs tested (p<0.05), while the 5 mmHg group was lower but non-statistically significant (p>0.05). The scores were also lower in the A group when compared to the B group, but this difference was only significant at 20 mmHg (p<0.05). Additionally, Seidel’s scores were lower in the C group when compared to the A group, but they were not statistically significant at any IOP (p<0.05). India ink inflow was significantly lower in the C group when compared to the other two groups (p<0.05). We did not find a statistically significant difference in the inflow of India ink between B and C groups. Finally, there was no correlation between India ink inflow and Seidel’s test scores in any group (A r= -0.04, B r= 0.32, and C r= -0.47).
Conclusions: :
We found the uniplanar 3.0 mm tunnel length incision to be the most efficient at preventing intraocular fluid outflow after Seidel’s test performance. On the other hand, the 2-step incision was the most effective incision at preventing inflow of India ink. Positive Seidel’s test was not associated with the inflow of bacterial-sized particles of India ink.
Keywords: small incision cataract surgery • cornea: basic science