• Wear of scleral lenses over longer periods of time may exacerbate corneal swelling, reports a study in the March 2016 issue of Optometry and Vision Science.¹ 

Researchers used Scheimpflug imaging to examine the corneas of healthy patients before and immediately after eight hours of high Dk miniscleral lens wear, finding that a low level of corneal edema occurred by the eight-hour mark. Though the level of swelling was less than typically observed following overnight eyelid closure, these findings do contradict earlier research that suggests hypoxia-related changes to the cornea stabilize at three hours of wear time, the researchers note.^2,3 They suggest further research be conducted. 

1. Vincent, S, Alonso-Caneiro D, Collins M, et al. Hypoxic corneal changes following eight hours of scleral contact lens wear. Optometry and Vision Science. 2016 Mar. 93(3):293-9.
2. Sarver MD, Polse KA, Baggett DA. Intersubject difference in corneal edema response to hypoxia. Am J Optom Physiol Opt. 1983 Feb:60(2):128-31.
3. Holden BA, Sweeney DF, Sanderson G. The minimum precorneal oxygen tension to avoid corneal edema. Invest Ophthalmol Vis Sci. 1984 Apr:25(4):476-80.  

• An unstable tear film may indicate candidates who will fail to take to gas permeable lens wear, reports a study in the March 2016 issue of Eye & Contact Lens.¹ Twenty-two participants were given GP lenses to wear daily for one month, with follow-up visits scheduled at one, seven, 15 and 28 days. Six patients dropped out due to discomfort; those that remained but reported dissatisfaction exhibited lower comfort scores and wear time due to dryness. 

1. Carracedo G, Martin-Gil A, Peixoto-de-Matos S, et al. Symptoms and signs in rigid gas permeable lens wearers during adaptation period. Eye & Contact Lens. 2015 Mar;42(2):108-14.

• Including organoselenium in the polymer of contact lens cases could inhibit biofilm formation, suggests a study published online in Eye & Contact Lens.¹ Researchers tested the effects of the material on the growth of Pseudomonas aeruginosa, Staphylococcus aureus, Stenotrophyomonas maltophilia and Serratia marcescens by incubating the bacteria overnight in the presence of both a polypropylene polymer containing organoselenium and the same polymer without organoselenium. Results indicated the presence of the organoselenium inhibited growth of all bacteria by nearly 100%.

1. Tran P, Huynh E, Pham P, et al. Organoselenium polymer inhibits biofilm formation in polypropylene contact lens case material. Eye & Contact Lens. 2016 Mar; [Epub ahead of print.]