Cataract Surgery and Dry Eye Disease

Prevalence, Effects of Preservative-Free Eyedrops and Artificial Tears in Pre-and Postoperative Care

Abstract

Modern cataract surgery, utilizing advanced lens technology, has evolved into a refractive procedure with a strong emphasis on refractive precision. Achieving this precision requires thorough preoperative assessment and planning, including ocular surface measurements and intraocular dimensions. The tear film is a critical component of the ocular surface, and disruptions due to dry eye disease (DED) can lead to inaccurate measurements. DED is a common and multifactorial condition that causes significant discomfort for the patient and can be triggered by cataract surgery. While numerous studies have focused on dry eye issues following cataract surgery, there is limited attention to preoperative dry eye assessment and treatment. There is generally a lack of consensus on which clinical tests for dry eye may be clinically relevant and uncertainty surrounding pre- and postoperative treatment. This doctoral thesis aims to enhance the understanding of dry eye concerns before and after cataract surgery by exploring the prevalence through various diagnostic tests and investigating the effects of preservative-free eye drops and artificial tears in pre- and postoperative care and additionally, exploring the effect of treatment with artificial tears on keratometry variability and refractive predictability. In a prospective cross-sectional study, we determined the prevalence of DED among patients scheduled for cataract surgery based on its signs and symptoms. Correlation analyses between tests were performed, and the association between DED and its signs and symptoms with age and gender was explored. Furthermore, a prospective randomized interventional trial was conducted where the patients were examined for DED before and six weeks after cataract surgery. We compared the effects on dry eye signs and symptoms of treatment with preservative-free dexamethasone, nonsteroidal anti-inflammatory drugs (NSAIDs), and trehalose/hyaluronic acid eyedrops with preservative-containing (benzalkonium chloride (BAC) dexamethasone and NSAIDs eye drops with preservatives after surgery. Last, in a prospective randomized controlled trial, we explored whether treatment with artificial tears before surgery affected the variability of keratometry measurements, improved the refractive precision, and whether the control group with non-dry eyes had better refractive precision than patients with dry eyes postoperatively. The results from Study 1 indicated that the prevalence of DED in patients scheduled for cataract surgery was 55.5% and was associated with the female sex. A majority of patients had meibomian gland dysfunction (MGD), and tear film osmolarity was the most sensitive diagnostic test. Study number 2 found no additional effect on dry eye parameters with treatment using preservative-free medication and lubricants compared to preservative-containing eye drops. Furthermore, patients diagnosed with dry eye preoperatively, regardless of treatment, improved after surgery compared to non-dry eye patients. The last study (Study 3) showed that pre-treatment with artificial tears two weeks before cataract surgery did not enhance the variability of keratometry measurements for patients with dry eyes, and there was no statistically significant difference in refractive precision between treated and non-treated eyes. This thesis highlights the need for a greater emphasis on testing for dry eyes during preoperative examinations, mainly using corneal fluorescein staining (CFS) and testing for tear film stability, as well as assessing Meibomian gland dysfunction (MGD). Before surgery, using topical steroids and NSAIDs, whether with or without preservatives, significantly improved dry eye symptoms in patients who already had symptoms. On the other hand, those with normal tear film before surgery might experience worse symptoms if they use medications that contain preservatives. This shows the importance of choosing preservative-free options whenever possible. Preservative-free treatments are more expensive and harder to handle, which emphasizes the importance of personalized treatment plans. Using artificial tears before conducting ocular biometry did not significantly reduce keratometry measurements' variability for patients with DED before cataract surgery. Furthermore, based on our findings, it's difficult to conclude that using artificial tears in a preoperative setting may benefit the patient.