Reply : Artificial tears for clearing tear-film precipitation during cataract surgery

Abstract

We thank Ho for his interest in our article. With our technique, usually no more than 2 drops of artificial tears are necessary to remove the troublesome tear-film precipitates for the completion of routine uneventful cataract surgery. However, some patients may squeeze their eyelids during the course of surgery, causing more meibomian gland secretions to accumulate on the corneal surface. In these cases, additional drops of artificial tears may be needed, although the secretions due to lid squeezing are not usually as intense as the precipitates encountered at the start of surgery. In Turkey, the most expensive preservative-free artificial tear product is Protagent SE (polyvinyl prolidone 2% solution). A pack containing 20 vials costs about US $7; thus, a vial costs about 35 cents. The least expensive is Refresh (polyvinyl alcohol 1.4% and polyvinyl prolidone solution 0.6%). A pack containing 30 vials costs about US $6; thus, 1 vial costs 20 cents. Although Refresh is less expensive, we prefer to use Protagent SE, especially in patients with more stubborn tear-film precipitates. A recent randomized comparative study conducted in our clinic,1 which included a preclinical animal toxicity study, showed that Protagent SE is more efficient than Oculotect Fluid Sine (polyvinyl prolidone 2% solution) and Refresh in clearing the precipitates. The gas-sterilization process is a fully automated process in which the surgical instruments and reusable accessory parts and other items such as reusable cannulas are sterilized as individual packages or in sets. The gas sterilizer works on a large number of packages at a time; thus, the cost of a few additional packaged artificial tear vials would not add to the total cost of the sterilization process. Alternatively, an artificial tear vial can be slipped into a cataract set to be gas sterilized. We agree that these precipitates can also be removed by gently wiping the corneal surface with a spear sponge soaked in BSS, as Ho describes. In fact, we used to make use of this technique and saw that although it was useful in clearing the troublesome precipitates, preservative-free artificial tears were more effective and easier to use. Using a spear sponge soaked in BSS has some disadvantages: First, wiping with a spear sponge usually has to be repeated because wiping the ocular surface may cause irritation and the patient may involuntarily squeeze his or her eyelids, causing more meibomian gland secretions to accumulate on the corneal surface. Artificial tears are obviously less irritating. Second, the surgeon would prefer to do the wiping, which would distract him or her, especially during the bimanual stages of the surgery; with artificial tears, the assistant surgeon applies the drops on the corneal surface without distracting the surgeon. Third, in Turkey, the cost of a 5 pack of spear sponges (Visitec) is US $5; thus, 1 spear sponge costs US $1. We support Ho's observation that continuous irrigation of the corneal surface with BSS is not only ineffective but also makes anterior segment visualization worse. We appreciate that Ho gave us the opportunity to further clarify issues related to cost-effectiveness and comparison of the 2 techniques.