scleral lens - size matters?

[painintheeye]

Hi Dr. G,

I am wondering about the varying sizes of a scleral lens. BFS's according its own description, is about the size of a nickel while others are generally much bigger in 20-23mm range. is bigger the better at providing therapeutic dry eye value since more sclera is covered and hence better overall relief? i would guess the larger the lens makes insertion and removal more difficult as well?

we've discussed plasma treatment earlier and i want to know if the durability of the treatment lasts for say a year only, can the same lens be re-treated or a new lens needs to be ordered?

are there other bandage lens suitable and effective for relieving symptoms of dry eye similar to scleral lens that one could try?

thanks again for your expertise and time.

Chris C

[DrG]

Chris,

The size range for scleral lenses is generally considered to be 16 - 23mm. For reasons of handling, I prefer the smaller sizes. I also prefer vented designs over sealed. When using a lens as a bandage, I prefer to begin with a soft silicone-hydrogel lens. That approach is much less expensive and with better patient acceptance, usually. Of course, soft lenses do not correct all forms of refractive problems. So, if you have lots of astigmatism, or post-LASIK aberrations, you may need the optical properties that only a rigid lens can supply.

I doubt that anybody can give a definitive answer to how long plasma treated surfaces stay wettable. The best answer I can give is to use the example of the Menicon Z lens. Without plasma treatment, that lens is virtually unwettable in the eye. I have dispensed many of those lenses over the years, and cannot recall ever having a wettability problem, which means that the plasma treatment lasts for the normal life of the lens, which varies for each person. Of course, this assumes that the patient takes necessary precautions in the handling and cleaning and does not use abrasive cleaners.

Can a lens be retreated? Only if the surface is in good condition, i.e. no scratches.

[painintheeye]

thank you

thank you Dr.G for your reply.

when you prescribe soft silicon hydrogel lens i am assuming the lens rests directly on the dry cornea? if there's no lasik done and the general health of the cornea is good but acqueous deficient, can this lens still work to relief the dry eye pain? or a relatively "wet" eye still needed for this type of lens to work?

chris c

[DrG]

One of the purposes of a bandage lens is to relieve pain and discomfort. Given that a silicone-hydrogel lens has a water content of 24%, it still needs a source. If the eye doesn't make enough, then it has to be added in the form of a rewetting drop.