Sodium hyaluronate and dry eye after cataract surgery

Senile cataract is an ocular pathology age-related, for which the treatment of choice is phacoemulsification combined with intraocular lens implantation. Ocular surface diseases are common after cataract surgery and can have a negative impact on patients' quality of life. In addition, the use of anti-inflammatory eye drops before cataract surgery can often cause damage to the epithelium and, subsequently, the alteration of the tear film due to the surgery can lead to an increase in local inflammatory factors. Finally, the corneal incision causes damage to the epithelial cells of the cornea and local anaesthesia can also cause discomfort to the ocular surface after surgery. All these factors are among the causes contributing to the onset of dry eye after cataract surgery. Moreover, with advancing age, both cataract and dry eye syndrome (which is the most common ocular surface disease) have a higher incidence. To reduce patients' discomfort, it is therefore important to find suitable treatments to lessen the impact of cataract surgery on the ocular surface. 

 Among the most interesting substances in this respect is the sodium hyaluronate, the sodium salt ofl'hyaluronic acida molecule capable of retaining water on the ocular surface and delaying evaporation of the tear film. A recent study investigated ocular surface changes after phacoemulsification in patients with age-related cataracts following the addition of drops with varying concentrations of sodium hyaluronate.

Conduct and design of the study

Nello studioThe authors examined the efficacy of 0.3% and 0.1% sodium hyaluronate eye drops in restoring the regularity of the corneal surface in patients who developed dry eye syndrome after cataract surgery. The drops were administered topically four times a day in 73 patients, divided into three groups: in group A, 30 patients received conventional therapy and 0.3% sodium hyaluronate eye drops; in group B, 31 patients received conventional therapy and 0.1% sodium hyaluronate eye drops; in group C, only conventional therapy was administered in 30 patients. Conventional postoperative therapy included eye drops with levofloxacin and tobramycin dexamethasone, both administered four times daily, and eye drops with bromfenac sodium, administered twice daily. Evaluations were performed at specific intervals up to 3 months postoperatively and included assessments of tear film stability and irregularity. 

Patients were then examined seven days, two weeks, one month and two months after surgery and significant differences were found in the Schirmer I test, tear film meniscus height and tear film break-up time values in both groups treated with sodium hyaluronate, compared to controls. Furthermore, the 0.3% concentration gave even better results two months after surgery. Corneal irregularity values also decreased more significantly in the 0.3% sodium hyaluronate treatment group than in the 0.1% sodium hyaluronate treatment group and the control group.

What are the implications of the study for clinical practice?

Overall, the study showed that sodium hyaluronate is able to restore tear film structure and corneal surface regularity, and that the 0.3% concentration is more effective than the 0.1% concentration. Thus, in the initial phase after phacoemulsification, where tear film stability is reduced, hyaluronate drops are an excellent choice for maintaining ocular surface health. 

The authors state that further prospective and comparative studies including patient-reported outcomes will be needed to establish with even greater certainty the role of sodium hyaluronate in the management of patients who develop dry eye disease after cataract surgery. However, pending such further confirmation, sodium hyaluronate eye drops may be considered a useful therapeutic option for patients with dry eye symptoms after cataract surgery.

1. Chen N, Zhang JS, Zhang TX, Fan BL, Ning Y. The effect of sodium hyaluronate on tear film stability in patients with dry eye syndrome after cataract surgery. Graefes Arch Clin Exp Ophthalmol. 2023 Apr;261(4):1011-1017. 
2. Wen Y, Zhang X, Chen M, Han D. Sodium hyaluronate in the treatment of dry eye after cataract surgery: a meta-analysis. Ann Palliat Med. 2020 May;9(3):927-939.