Over the last few weeks, on cloudy day’s, I have noticed an array of errors with some of your tennis swings.  The balls have not been very hard shots, so I started to think deeper into what the cause may be.  It dawned on me, that some players that have prescription glasses, may not be wearing them for tennis.  After asking several player’s in my clinic’s about this, sure enough, some of the player’s forgot to wear their glasses or didn’t think they needed to.  Whether you are near sighted or far sighted,  the game of tennis requires player’s to hit moving tennis balls near to us or far from us.  So seeing the ball is essential. My suggestion is if you read and/ or drive with glasses, try wearing prescription sun glasses,  regular prescription glasses or contacts for tennis.,  I bet it will help and you will have a reduced number of unforced errors!!