Corneal thickness and endothelial density before and after cataract surgery

Background/aims-Deturgescence of the corneal stroma is controlled by the pu mping action of the endothelial layer and can be monitored by measurement o f central corneal thickness (pachymetry). Loss or damage of endothelial cel ls leads to an increase in corneal thickness, which may ultimately induce c orneal decompensation and loss of vision. Little is known about the effect of moderate reductions in endothelial cell number on the thickness of the c orneal stroma. This study aimed to investigate this matter further using pa tients who had incurred moderate decreases in their endothelial cell counts as a result of cataract surgery. Methods-Central corneal thickness was measured 1 day before surgery, 1 day after surgery, and again at 3 months or 1 year. Endothelial cell counts wer e also performed 1 day before surgery and thereafter at 3 months or I year after surgery. The relationship between these two parameters was assessed s tatistically. Precise measurements of central corneal thickness were made b y optical low coherence reflectometry. For comparative purposes, this param eter was also determined by ultrasonic pachymetry. Central corneal endothel ial cell numerical density was estimated on photomicrographs taken with a s pecular microscope. Results-All patients had significant postoperative corneal swelling on the day after surgery; preoperative values were restored by 3 and 12 months, ev en though significant endothelial cell losses had occurred. No correlation existed between central corneal thickness and central corneal endothelial c ell numerical density. Measurements estimated by ultrasonic pachymetry were more variable and significantly higher than those determined by optical lo w coherence reflectometry. Conclusion-As long as the numerical density of the corneal endothelial cell s does not fall below the physiological threshold, a moderate decrease in t his parameter does not compromise the pumping activity of the layer as a wh ole.