Soft contact lens cleaning: rub or no-rub?
OBJECTIVE
To compare effectiveness of cleaning with and without rubbing of soft contact lenses.


METHODS
Three-hundred new biweekly disposable hydrogel lenses (Ocufilcon D, FDA Group IV; 55% water content) were artificially deposited with serum albumin, hand cream (semi-transparent deposits) and mascara (black deposits). The treated lenses were randomly divided into three groups, each group cleaned by one of three methods of cleaning--Rubbing (R), No-Rub following the manufacturer's instruction on duration of rinsing (NR1) and No-Rub with a shorter duration of rinsing (NR2). Four commercially-available multipurpose solutions (MPS) and a saline were used. The cleaning effectiveness was determined by the amount of deposits remaining on the contact lenses after cleaning, assessed with the aid of a slit-lamp. The level of deposits remaining (in terms of coverage of lens surface) were determined using a five-point scale [0 (no observable deposits)--4 (>80% deposits remained)] for semi-transparent deposits (protein and hand cream) and black deposits (mascara). The investigators were masked as to the solutions used (except for one MPS which has a different rinsing time than the other MPS), and the investigator who assessed the deposits left on the lenses did not know which solution or cleaning method was used to clean each lens.


RESULTS
Lenses cleaned by the R method were significantly cleaner than those cleaned by methods NR1 and NR2. No significant difference was found between lenses cleaned by NR1 and NR2 methods. The median grade of deposits for lenses cleaned by R method was 0.5 for both semi-transparent and black deposits. For lenses cleaned by NR1 and NR2 methods, the median grade of deposits left on lens surfaces was 4.0 for both types of deposits. Different solutions used did not affect the level of deposits left on lens surfaces for all three cleaning methods.


CONCLUSIONS
Not rubbing the soft lens when cleaning is ineffective in removing loosely-bound deposits. A longer rinse, as recommended by the manufacturers, does not remove significantly more deposits than a shorter rinse with the MPS. This work supports the view that contact lens wearers should be encouraged to rub their lenses when cleaning.
Cho
Pauline
P
School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China. sopaulin@polyu.edu.hk
Cheng
Suk Yi
SY
Chan
Wai Yip
WY
Yip
Wing Kin
WK
D000418:Albumins; D018639:Contact Lens Solutions / Q000737:chemistry / Q000592:standards*; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D003358:Cosmetics; D004203:Disinfection / Q000379:methods*; D004209:Disposable Equipment; D017276:Friction; D006801:Humans
D000418:Albumins; D018639:Contact Lens Solutions; D003358:Cosmetics