Contact Lens Intolerance: The reason contact lenses are prescription devices. This is severe corneal and lid inflammation that can lead to scarring of the cornea and hence permanent vision loss. Three main variables cause contact lens intolerance (while not altogether independent) :

Improperly fitting lenses
Corneal hypoxia/ischemia (cornea not breathing properly)
Hyperallergic reactions to protein buildup.

Toric: Patients who have astigmatism (eye shaped more like a football than a basketball) will often need a Toric Lens to achieve the clearest vision
 
Multifocal: Typically for presbyopes (individuals 40 years and older requiring a separate prescription for reading and distance), these lenses provide clear vision at both distance and near. Unlike progressive lenses or bifocals, patients don’t need to look through specific parts of the lens to see clearly but instead have simultaneous distance and near vision at all times. The trade off? Multifocal lenses will not provide as crisp vision as glasses, however to our surprise most patients are able to achieve 20/20 at both distance and near. We are finding over 90% of patients successful with multifocal lenses.
 
Silicone Hydrogel Lenses: Silicone is most breathable material used in contact lenses. The availability of this material is nothing new. However, while breathable, it is not the most comfortable material (very poor water retention) and early silicone based contact lenses had very low patient acceptance/comfort. The new generation of Silicone Hydrogel lenses now gives patients the best of both worlds, breathablility and comfort as manufacturers are utilizing new technologies to make silcone based lenses retain more water to the point that they now have even higher comfort acceptance than traditional contact lenses.
 
Dailies: These lenses are single use, single day lenses. No solutions nor cases required. The reason why many clinicians consider this modality the healthiest is due to the fact that patients have less protein exposure (since lens is thrown away as opposed to reworn with protein buildup) and less exposure to preservative from contact lens solutions. Our take? Only until recently can we agree that certain Dailies contact lenses lay claim to be the healthiest lenses available today.