Yes, I suppose that you mean contact lens used after phacoemulsification of the cataract to secure corneal incision (without sutures) and prevent infection-endophthalitis with increased rates due to opening of surgical wound during blinking.

Contact lenses are not needed after routine phacoemulsification, the ports are self sealing and do not usually leak. In cases of a leak, it is better to suture them with 10-0 nylon. Contact lenses will also interfere with the post operative drug regime and will simply delay the rehabilitation, especially in cases with modearte to severe inflammation.

In cases of epithelial defects post cataract surgery, we prefer to load the patient with Vitamin C and patch overnight, usually they heal within 24 hours.

Contact lenses [ CLs, whether soft or hard (rigid gas permeable), but usually soft) are not routinely used and should be avoided after uncomplicated cataract extraction (whether intra-capsular, extra-capsular, small incision cataract surgery or phacoemulsification) specially to act as a bandage or cover (referring to your question). This is because:

1. Cataract patients are usually elderly people and may have an increased chance of dry eye. The central and optical part of the cornea is dependent on the tear film to get its nutrition from, of particular critical importance is oxygen (used for corneal cell metabolism), which comes from the air in front of the cornea. If the patient's eye is dry and a low water content (usually a 130 if it is not wet by tear substitute regularly and as the need arises. Even high Dk value thin soft hydrogel CL need to be wet to allow oxygen through them.

2. CL use may increase the risk for post-operative infection. The basic rule of contact lens wear is to take it out when no longer needed because the longer the it is on the eye the higher the rate of infection as shown in several studies before. There is a risk to benefit ratio observed in the use of CL which is another topic.

May be the bettter question is: When a CL can be used post-cataract surgery? Here are some of the relative indications for its use:

1. In cases of persistent epithelial defects usually experienced in diabetic patients (usually with concomitant dry eye) and other diseases after 2-3 weeks post-cataract extraction [usually what is suggested is pressure patching for the first 2-3 weeks (which allows minimal surface epithelial cell growth disturbance when blinking) and this could also be supported by oral intake or topical use of Vitamin A which increases epithelial cell mitosis] who have basement membrane abnormalities in attachments. The use of thin Bandage CL (not CL used as a bandage per se) with high Dk value may be appropriate since its main mechanism of action is allowing adhesion complexes to establish since usually the defect is due a failure of epithelial cell and attachment complexes adhesion (reference: Jouranal of The Ophthalmological Society of United Kingdom, 1970's, Topic : Cornea and Dry eye)

2. In cases of corneal edema, CLs can be used to flatten and make the epithelial surface more regular specially if bullae are present. It also decreases the foreign body sensation or even pain when these bullae rupture. It has the added benefit of acting as a depot of topical eye drops in particular 5% sodium chloride, antibiotics and steroids. A naked eye being treated with hypersalt solution should ideally be without corneal epithelial defects as the hypersalt solution normally take out water by osmosis. The primary difference between osmosis and diffusion is the presence of a semi-permeable membrane (represented in the cornea as an intact epithelium) which allows only water to exit a less concentrated medium to the more concentrated medium allowing water to be drawn out from the corneal stroma to decrease its edema. In cases of cornea's with epithelial defects the process may involve diffusion where the concentrated solute (sodium in particular) with its solvent (water mainly) may enter the defect an equilibrate in the corneal stroma minimizing or negating the hypersalt solution effect on corneal edema. With the use CL in corneal epithelial defects with corneal edema, it can act as a temporary but imperfect semi-permeable membrane which may slightly decrease corneal edema. This is the reason that in our Cornea and External Eye Subspecialty Clinics in Manila Central University Hospital and Ospital ng Makati, hypersalt solutions are used together with bandage contact lens or used in end stage endotheliopathies with chronic edema unresponsive to other previous medical treatments.

3. In some cases of leakage of the cataract wound site where a regular thick extended wear wide diameter scleral soft CL may be appropriate. This may include corneal perforations of usually < 2mm assisted by other forms of medical management,

Hope I answered your question and clarified some other points

Ideally, after routine uneventful phaco surgery, there is no need to put contact lens.