Optometrist Perspective by Harvey Yamamoto,OD

Harvey Yamamoto, ODIt was 4 years ago that while attending an OAA convention in Houston that I began to hear about scleral lenses.  Several lecturers began to incorporate scleral lenses into their notes.  Apparently with the advent of higher DK materials – a rebirth of scleral lenses became dug out of the grave.  In the early pioneering days, a few contact lens fitter began to fit scleral lenses molded out of glass.  I take my hat off to those pioneers for the introduction of sclerals.

Why, I ask?  Why on earth would anyone wish to wear sclerals when we have soft lenses, hybrids and gas perm contact lenses?  It is no secret that not everyone can wear contact lenses.  Many patients have terminated the wearing of contact lenses due to dryness.

The lecturers began to come out of the woods proclaiming a new savior was born… sclerals , semi-sclerals , mini-sclerals & corneo-scleral.  I began to look into the matter.  Four years ago, I found no literature about the fitting parameters on sclerals.  I only heard through the grapevine that they were 18.2mm in diameter.

One day while having my teeth cleaned, the new dental hygienists asked me, “Sir, what do you do for a living?”  Gagging with my mouth filled with her fingers I blurted out, “Optometrist.”   Here is where this story becomes interesting.  She stopped for a moment and then said, “Do you fit scleral lenses?”  I sheepishly replied, “Not yet.”  She replies, “My mother lives in Boston and she just paid $8,000 for her sclerals and she loves them.  She says that she had such dry eyes that she became bedridden but now she is working once again.”

I almost swallowed her tools down my throat.  I promised her that I would begin to fit sclerals so I could fit her mother one day.  That was 4 years ago.  I began to read whatever materials that I could find on the subject.  I called several manufacturers for scleral blanks.  Rich Jeffries of Paragon Vision Science responded and donated 100 scleral buttons for my R&D.

I worked 24/7 for 3 months and soon became discouraged with poor results.  After a year of stopping the R&D, I began once again in earnest but with little results.  Three years later, I made another attempt but once again the results did not yield anything.  Finally, this summer, I decided that I would order special tools to aide my cause.

I began by ordering larger diamond impregnated tools.  I needed patients to work on.  I began fitting my staff one by one.  Most of the buttons today are UV treated and thus trying to obtain a decent NaCl pattern was difficult at best.  Finally, one night while I was wrestling with myself, it dawned on me that perhaps our SD-OCT anterior seg software might be the answer.

The following morning, I rushed to the office and placed a scleral lens on my staff.  I was pleasantly surprised to find out that the Anterior Seg software on our Cirrus OCT was able to tell me precisely how many um’s was between the lens and the cornea.  Then I proceeded to check the edge lift and discovered that the edge lift was much too high leading to a very uncomfortable fit.  Little by little with each passing day, I learned the secrets of fitting scleral lenses. With the aide of the OCT, it taught me everything that I know about sclerals.  My favorite lens has become the Corneo-Scleral lens.

I quickly discovered by playing around that patients did not like the larger diameter lenses- 18.0 mm.  I cut the diameter down to 16mm and then 15mm with better results. Today, my lens diameters are 13.5 to 14.2mm.  The relationship between the Base Curve and the P.C. is very important when it comes to fitting corneo-scleral lenses.  I like to fit these lenses with a slight vaulting in the central zone – 40 um.  The vaulting is not always easily controlled especially when it comes to Pellucid Marginal Degeneration.

I recently had a patient with Pellucid referred to me for contact lens evaluation.  The patient exhibited 9.5 diopters of astigmatism and her previous doctors had finally given up.  Now it was my turn to see what we could do for this patient. The K reading in the left eye: 55.50 x 46.00 diopters.  The best Rx that we could find by trial and error: -4.00 -8.00 x 20 = 20/100.

We tried a corneo-scleral lens on the left eye: B.C.: 6.20   Diam: 14.0 mm   PC1 = 11.50/1.50   PC2  =  12.25/.5  RX: -19.50.  The lens fit extremely well with good central vaulting = 25 um  and edge lift = 125 um.  The lens exhibited a small footprint on the corneo-limbal zone with slight scleral touch with a good edge lift:  BCVA: 20/25.  The patient was extremely astonished and happy with the result.  A 4 week follow up visit showed no corneal irritation with no staining and no evidence of scleral depression.

We also made the patient a bitoric lens which also stained nicely with NaCl but the V.A. = 20/70.  The patient elected to keep her Corneo-Scleral lens over the Bitoric.  We fitted the right eye with a standard spherical gas perm lens = 20/20.

Working with scleral lenses now for 4 years, I am still learning about these lenses.  No two patients are alike.  I like the challenging cases which serve to stimulate my gray matter and I will continue my quest to perfect the fitting technique.  With each fitting episode, I feel more and more comfortable with the designing of each lens.  I can make minor adjustments if the lens happens to impinge on the sclera by increasing the P.C. to a flatter number.

In all my years of fitting contact lenses – nothing has equaled the challenge of fitting scleral lenses.  These lenses have tested my patience to the nth degree and the results are beginning to make believers out of my difficult patients.  The profit margins on these lenses are incredible and can make one’s practice into a gold mine.  Don’t be afraid to explore into the beyond.  Take one step at a time.  The learning experience is similar to fitting Ortho-K lenses but much more intense with many sleepless nights.

After 4 intensive years of walking through mud, I can finally begin to see the light at the end of the tunnel.  Now the tunnel appears to be well lit and I can find my way home.

I’m the odd man out.  I will not fit any gas perm lens on a patient until I learn “the art “of manufacturing them.  I need to know the A,B,C’s of any design before I feel comfortable in putting them on someone’s eyes.  Over the years, I have discovered the hidden secrets to fitting Keratoconic patients, High Astigmats, Multifocals, and now Sclerals.  I’m wondering what could be lurking around the corner.

Half-way through the exhaustive learning curve I threw in the towel on 3 different occasions.  By just leaving everything on the table for several months at a time, I would re-energize my mind to where I could begin the R&D.  At times, it was like walking through a blizzard with zero visibility and no guide dog to assist when I fell on my knees.  My favorite material has become the HDS 100.  Many thanks to my staff who patiently gave me their eyes to become my playground.  Without their co-operation, it would be like building a car without an engine.

Each staff member would tell me, “Doctor, you are getting close.”  With words of encouragement, I would continue digging and digging.  At times, I would slip backwards and have to start all over again.  Working with large buttons took a great deal of time learning how to cut, polish, & edge.  I have spent a small fortune in building up an inventory of specialized scleral tools but it was worth every cent.  My wife took over the surfacing lab duties which afforded me to be able to remain focused on the sclerals.

A Note to my readers: I hope that my stories are about gas perm fittings are not boring to everyone.  Fitting gas perm lenses has kept me interested in optometry for most of my career.  No two cases are exactly alike but the experience of fitting difficult cases certainly bleeds from one case to another.  I hope that my experience will serve as inspiration to some – especially the young fitters who are finding their way around the contact lens arena.   Don’t forget lenses that once again on the up rise like Ortho-K lenses that can really turn your practice around.  Have fun, my friends.

© 2011 C&E Vision's Industry News Feed. All rights reserved.
Service Provided By CandE Vision Services.
Content Protected Using Blog Protector By: PcDrome.