Evaluation of endothelial cell function with anterior segment fluorophotometry in pseudophakic patients

Functional evaluation of corneal endothelium by combined measurement of corneal volume alteration and cell density after phacoemulsification

PURPOSE

To assess a new method of functional evaluation of corneal endothelium using combined measurement of corneal volume alteration and cell density (CD) after phacoemulsification.

SETTING

Nippon Medical School Hospital, Tokyo, Japan.

METHODS

Phacoemulsification was performed in 28 cases. The corneal volume within 3.0 mm and 10.0 mm circles of the cornea was measured using Scheimpflug imaging (Pentacam, Oculus, Inc.) and the cell density, using specular microscopy (Noncon Robo, Konan Medical). The volume stress index (VSI), a parameter for measuring functional evaluation, was calculated by dividing the volume increase within the 3.0 mm circle (preoperative corneal volume - corneal volume at time of measurement) by the central cell density value. The resulting value is indicative of the amount of postoperative increase in corneal volume with which each corneal endothelial cell should be able to cope.

RESULTS

Three months after surgery, the 3.0 mm corneal volume returned to preoperative values, while the 10.0 mm corneal volume remained significantly higher than preoperatively. The cell density values did not significantly change throughout the study. The VSI showed a significant decrease by 7 days after surgery followed by a gradual decrease until the end of the study. At 3 months, the VSI value was significantly smaller than at 1 day.

CONCLUSION

The corneal volume increase after surgery may be indicative of the degree of the endothelial damage in the area; thus, the VSI may be useful in the functional assessment of the corneal endothelium.

Corneal endothelial function after extracapsular cataract extraction and phacoemulsification

PURPOSE

To compare the morphology and function of the corneal endothelium in the early postoperative period after extracapsular cataract extraction (ECCE) and phacoemulsification.

SETTING

University Eye Clinic of Trieste, Italy.

METHODS

In this prospective, randomized study of patients scheduled for cataract surgery, 40 patients were divided into two groups of 20 patients each. Group 1 had ECCE and Group 2, phacoemulsification; both had capsular bag intraocular lens (IOL) implantation. Preoperatively and 7 and 30 days postoperatively, a complete ophthalmological examination, endothelial specular microscopy, ultrasonic pachymetry, and anterior segment fluorophotometry were done. Visual acuity, endothelial cell density, cell size variation coefficient, corneal thickness, endothelial permeability coefficient, and endothelial pump function were studied.

RESULTS

Visual acuity was better 7 days after phacoemulsification than after ECCE, but no differences were observed after 30 days. No significant differences in postoperative loss of endothelial cells were found between the two groups. Coefficient of variation in size, corneal thickness, and endothelial permeability significantly increased in both groups 7 days postoperatively, but only in the ECCE group 30 days postoperatively; the differences between the two groups were statistically significant. Endothelial pump function significantly increased after 7 days in only the phacoemulsification group.

CONCLUSIONS

Functional endothelial failure occurred in the early period after ECCE. Phacoemulsification seemed to minimize postoperative functional damage to the endothelium.