Corneal endothelial cell density following cataract surgery in eyes with previous blunt trauma.

Sir,

We read the article by Yeniad B, Corum I, Ozgun C1 with keen interest. We did note some discrepancies in the numbers of subject reported in the text and the figures. In particular we draw attention to the text that states the study population consists of 31 subjects in the traumatic cataract group and 30 healthy subjects with senile cataract in the control group. However, figure 1 presents only 21 patients in the traumatic cataract group and 20 subjects in the control group. Similarly in figure 2 the article describes the distribution of corneal endothelial cell density in 61 healthy eyes (30 eyes in the control group and 31 contralateral eyes in the traumatic cataract group); however, the figure presents 40 eyes. The authors need to address the discrepancies between the text and figures.

Furthermore, Yeniad and colleagues1 indicate that the control group comprised of healthy subjects with senile cataract. The mean age of the patients in traumatic cataract group (48 years) was significantly younger than the mean age of senile cataract group (55 years). However, the authors did not report the mean ages of the two traumatic cataract subgroups. According to [Figure 1] there were 6 patients below 31 years in the traumatic cataract group without age-matched controls. Yeniad and colleagues1 should include age-matched patients in the control group rather than only senile cataract patients. Corneal endothelial cell density (ECD) differs with age. Age and ECD show a negative correlation with endothelial cells decreasing by 0.1% for every year of life.23 In the Discussion, Yeniad and colleagues state that 10 out of 12 patients in the complicated surgery subgroup had one or more coexisting clinical findings such as iridodonesis, phacodonesis and zonular rupture. However, these additional clinical findings are not reported in the Materials and Methods or in the Results.

Yeniad and colleagues1 did not report the hardness of nucleus or the technique of nucleotomy. In addition to the several factors that Yeniad and colleagues1 mention, endothelial cell loss depends on the technique used to remove nuclear material, nucleus hardness, ultrasound power, the type of phacoemulsification unit, age of the patient and the presence of corneal disease.45 Endothelial cell loss after cataract surgery ranges from 4 to 25%.4 For example, one study reported no difference in endothelial cell loss after phacoemulsification (10%) and extracapsular cataract extraction (ECCE) (10%).5 The phacoemulsification group actually had a higher rate of cell loss in hard cataracts (18.9% vs. 11.8%).5 The factors associated with greater cell loss in the study included hard cataract, age, capsule break and vitreous loss.5 Yeniad and colleagues1 report a 16.7% decrease in ECD in the complicated surgery group which appears reasonable. Median endothelial cell loss of 14% has been reported 12 months after combined pars plana phacofragmentation, vitrectomy, and Artisan lens implantation in the management of traumatic subluxated cataracts in adults.6

Yeniad and colleagues1 conclude that patients with cataract due to blunt trauma had a decreased endothelial cell count, which was significantly aggravated by cataract surgery. However, blunt trauma does not appear to play any role in decreased ECD after cataract surgery because ECD decreased significantly after cataract surgery even in the control group. Moreover, the difference in the decrease in ECD between the two groups was not significant.