Phaco reduces IOP regardless of diabetes
Click Here to Manage Email Alerts
Phacoemulsification caused a significant and persistent decrease in IOP and corneal resistance factor among both patients with type 2 diabetes and those without diabetes, whereas corneal hysteresis recovered to preoperative values among the diabetic group, according to data published in Cornea.
João N. Beato, MD, MMSc, from the São João Hospital and University of Porto in Porto, Portugal, and colleagues recruited 44 patients with diabetes and 44 patients without diabetes. The researchers evaluated corneal-compensated IOP (IOPcc), corneal resistance factor (CRF) and corneal hysteresis (CH) after successful phacoemulsification.
“It is important to recognize that CH and CRF are parameters that reflect the viscoelastic nature of the cornea, but they are not directly related, and alterations in tissue structure can lead to independent changes in each parameter,” Beato and colleagues wrote. “CH is known to mainly reflect the viscous damping capacity of the cornea to an applied force defined by a specific air-pressure curve; whereas CRF gives information on the global corneal resistance against deformation and takes into account the influence of [central corneal thickness (CCT)].”
At 1 month and 6 months follow-up, the mean postoperative CCT did not change significantly from baseline in either group. At 6 months, IOPcc and CRF were significantly lower in both groups (P < .001).
CH was significantly lower than baseline at the 1-month visit among patients with diabetes, but not at the 6-month visit. Patients without diabetes showed no significant change in CH from preoperative assessment. Additionally, the researchers found no difference in CH variations between groups.
Beato and colleagues noted that the study cohorts were of a small size, but a strength of the study was a longer follow-up than previous published literature.
“Further prospective studies with adequate control of confounding factors (IOP and CCT) and longer follow-up may support our findings and clarify the role of long-term poor metabolic control on the postoperative corneal biomechanical changes,” they wrote. – by Talitha Bennett
Disclosures: The authors report no relevant financial interests.
Perspective
Back to Top
Brad Sutton, OD, FAAO
It is well known that IOP tends to decrease, at least to some degree, after cataract surgery. Data from previous studies have also shown that corneal biomechanical properties can sometimes be affected by cataract surgery as well, thus potentially impacting IOP readings after surgery. This study set out to determine if the biomechanical properties of the cornea were affected differently in patients with diabetes than those without diabetes.
Preoperative values for IOP, CH and CRF were compared with postoperative values in 44 patients with diabetes and 44 matched patients without diabetes. So, was there a difference between patients with diabetes and those without? In a nutshell, no. IOP and CRF were each found to be significantly lower in both groups after surgery, while CH was found to be equal to preoperative values in both groups by 6 months after surgery. It did, however, take the corneas of diabetic patients longer to recover to their baseline CH values. In the end, at least in this study population of patients, the corneas of patients with and without diabetes appear to react very similarly to cataract surgery.
Collapse
Read more about
Click Here to Manage Email Alerts