Optimizing the ocular surface in cataract surgery patients unaffected by dry eye

Even patients without pre-existing dry eye disease (DED) who are scheduled for cataract surgery can benefit from perioperative use of artificial tears, and particularly by starting the treatment preoperatively, according to the findings of a retrospective study conducted by Italian investigators.

The researchers analyzed data from the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire, tear break-up time (TBUT) measurements, and corneal fluorescein staining (CFS) in three groups of patients comprised of those who did not use any artificial tears perioperatively (n = 140); patients who began to instill artificial tears one week preoperatively and continued for two months postoperatively (n= 139); and a cohort that used artificial tears postoperatively for two months (n = 140). The DED-related evaluations were performed preoperatively and at follow-up visits occurring at 1, 4, and 8 weeks after surgery. The artificial tear product was a commercially available lubricant formulation containing hydroxypropyl guar and hyaluronic acid, and all patients were treated with the same perioperative regimen of antibiotic and anti-inflammatory medications.

The results, published in Clinical Ophthalmology [Favuzza E, et al. Clin Ophthalmol. 2020;14:1769-1775] showed statistically significant benefits of treatment with the artificial tears for mitigating surgically-induced signs and symptoms of DED. Statistically significant differences favoring the group that started using the artificial tears preoperatively compared with the group using the ocular lubricant only after surgery were seen in analyses of SPEED scores and TBUT.

Based on the findings, the investigators concluded that the artificial tear product was effective in protecting the ocular surface, particularly if initiated in the preoperative period. Noting that DED can lead to biometric errors and adversely affect patient comfort and vision after surgery, they stated that the findings highlight the importance of improving the homeostasis of the ocular surface not only in patients with established DED but also in those without frank disease or evident DED risk factors.

Study design

The study identified patients who had undergone unilateral cataract surgery across 17 centers in Italy. A total of 419 patients met the inclusion criteria that required eligible patients to be at least 50 years of age and have undergone an uncomplicated procedure with a clear corneal incision, IOL implantation in the capsular bag, and postoperative treatment with dexamethasone + tobramycin four times a day for ten days and nepafenac 0.1% three times a day for one month.

In addition, patients needed to have data from DED diagnostic tests conducted between 30 and 7 days before surgery and at 1, 4, and 8 weeks postoperatively. Patients were excluded if they had pre-existing DED, which was diagnosed based on a Schirmer test without anesthesia <7 mm/5 min, TBUT <10 seconds, SPEED score >4, and CFS score >1, or if they had any other findings that could confound the results.

Preoperatively, the three study groups were well-matched with respect to mean age (~72 years), mean Schirmer test score (~13 mm/5 min), mean TBUT (~12 sec), and percentage of eyes with a CFS score = 0 (65% to 76%). The postoperative data from all groups were consistent with previous reports showing that cataract surgery can induce signs and symptoms of DED.

Mean SPEED questionnaire scores did not change significantly in groups that were using artificial tears but increased significantly (worsened) at week 4 in the untreated patients. The differences in mean SPEED scores were statistically significant favoring both groups using the artificial tears versus the untreated group at all follow-up visits. The investigators noted that 25% of the patients in the untreated group had SPEED scores corresponding to mild-moderate dry eye symptoms at eight weeks after surgery.

In addition, a statistically significant difference favoring the group starting artificial tear use preoperatively compared with the group treated only postoperatively was noted at postoperative weeks 1 and 4.

The TBUT was significantly higher in both groups using the artificial tears compared with the controls at all follow-up visits, and mean TBUT fell to below 10 seconds postoperatively only in the control group. In addition, TBUT recovered faster in the group using artificial tears preoperatively compared with the group that was treated only after surgery. At the week 4 postoperative visit, the TBUT was higher in the group that started artificial tear use preoperatively compared with the group treated only postoperatively. The investigators noted, however, that while the difference was statistically significant, it was not clinically significant.

The results for CFS showed that patients using artificial tears had less corneal damage after surgery than their untreated counterparts. Among patients who used the artificial tears preoperatively and postoperatively, a small minority had CFS scores of 2 (7.2%) or 3 (0.7%) at the week 1 postoperative visit. In this same group by week 4, more patients had a CFS score of 0 compared with baseline, and the percentage was increased further at week 8.

A similar pattern of early worsening in CFS scores and subsequent progressive improvement was noted in the group that used artificial tears postoperatively only and in the untreated group. However, among patients who used the artificial tears after surgery, ~6% of patients had a CFS score >1 at week 4, while in the untreated group a CFS score >1 was found in 20% of eyes at week 1, 13% at week 4, and 6.4% at week 8.