Solving 3- and 9-o’clock staining the hybrid way
-managing mechanical pressure & hypoxic conditions on the peripheral cornea-
Halina Mańczak MD PhD
A 62-year-old female suffering from bilateral keratoconus since age 10 was referred to my practice because of (R)GP lens wear intolerance. She had started (R)GP lens wear just after the diagnosis was established. Besides significant lens intolerance, her chief complaint was dry eye symptoms. All symptoms had increased over the previous year.
Visual performance (with (R)GP lenses):
VA RE: 0,6 +2/5 ; 20/33 +2/5
VA LE: 0,3 +1/5 ; 20/70 +1/5
There was a lack of stereopsis.
Slit lamp biomicroscopy:
We noted grade 4 3- and 9-o’clock staining in both eyes due to (R)GP lens wear. Dellen, pronounced neovascularization and peripheral clouding at the horizontal axis of the cornea was observed. The diameter of both (R)GP lenses was small, and both lenses were too flat. The lenses were riding low as well. To overcome the 3- and 9-o’clock staining, we recommended ClearKone lenses (hybrid, vaulted lenses produced by Synergeyes Inc). Piggyback lens wear as a temporary solution was also suggested, but the patient was unwilling to wear lenses in this modality.
To allow the cornea to return to baseline levels, contact lens wear was discontinued for two weeks. If the change in corneal shape during the initial period of vaulted lens wear is not calculated into the vault (VLT) of the lens during fitting, there is a significant chance that within a short period of time, the cornea will touch the back surface of the lens. ClearKone VLT calculation allows for 50-100 micrometers more of clearance, compared to lenses calculated for neophytes, to compensate for this.
After discontinuing (R)GP lens wear for two weeks, ClearKone hybrid lenses specially designed for keratoconus were fitted, and improvement in vision in comparison to vision in (R)GP lenses was achieved. The lens parameters were as follows:
RE: CK VLT 500 / Sc S / -5,00; Vis 0,8 -1/5 VA 20/25+1/5
LE: CK VLT 450 / Sc S / -4,50; Vis 0,9 -1/5 VA 20/23 -1/5
Improvement in Signs & Symptoms
Symptoms and signs started to resolve right after the hybrid lenses were dispensed. It took 2 months for large neovascular vessels to decrease in diameter (figure 1, to right). In addition, the dellen healed, and the cornea became more transparent. Stereo vision of 40” was also achieved.
Slight alterations after one year were made to the lens (–0.25D to right lens power and a decrease in radius of the skirt curve to Z (S2). Except for the fact that the patient, due to fingernails that were too long and improperly shaped, damaged her lenses while trying to remove them, she remained successful with the hybrid lenses.
After that time, signs of 3- and 9-o’clock staining reappeared in both the right eye (grade 1 to 2) and the left eye (grade 3). The ClearKone skirt is made from a low Dk hydrogel material. Because of insufficient oxygenation of the peripheral cornea, wear of the ClearKone lenses over time resulted in neovascularization mainly in the upper limbal areas of both corneas.
It was fortunate that at this time the UltraHealth (Synergeyes Inc) lenses became available. Thanks to the implementation of a hyper Dk (130) (R)GP material and a silicone hydrogel skirt (Dk=84), UltraHealth lenses have significantly higher overall Dk levels in comparison to those of ClearKone (respectively, a Dk of 100 for the rigid portion and 9 for the soft skirt).
The fitting approach for UltraHealth is different than that for ClearKone. UltraHealth lenses are fitted flatter, both the (R)GP portion as well as the skirt, so it is not possible to order UltraHealth lenses based on ClearKone fitting parameters. The differences result from significant changes in the landing zone design as well as from physical properties of the silicone hydrogel material.
Following is a comparison of the parameters used for the ClearKone lenses and for the UltraHealth lenses in this particular case. Note the 100-micrometer decrease in vault and the two steps flatter skirt of the UltraHealth lenses. An increase in VA was noticeable.
RE VLT 500 / SC Z / -5,25; Vis 0,3 +1/5 VA 20/70 +1/5
LE VLT 450 / SC S / -4,50; Vis 0,9 +1/5 VA 20/23 +1/5
RE VLT 400 / SC M / -3,25; Vis 0,6 +1/5 VA 20/33 +1/5
LE VLT 350 / SC F / -1,75; Vis 1,0 VA 20/20
After refitting the UltraHealth lenses, signs of 3- and 9-o’clock staining resolved. Large vessels resulting from 3- and 9-o’clock staining (figure 2, to right) as well as vessels that were triggered by hypoxia almost all turned into ghost vessels. There is no longer any fluorescein staining related to this condition. The dry eye symptoms decreased substantially, and the patient maintains 12-14 hours of comfortable lens wear every day.
Vision in the hybrid lenses could be farther improved by prescribing spectacles to correct the internal astigmatism.
OR RE: sf +1,25 cyl – 2,00 ax 1150 Vis 0,7+1/5 VA 20/27+1/5
OR LE: sf +0,75 cyl – 1,00 ax 600 Vis 1,25-1/5 VA 20/15-1/5
In addition, higher order aberration (HOA) levels, MTF and PSF were significantly improved with these lenses. The difference is apparent in the aberrometry map (figure 3, to right).
Hybrid lenses are a useful tool in modern contact lens correction of protruded corneas. These lenses prove to be helpful in reducing or eliminating complications such as 3- and 9-o’clock staining caused by (R)GP lens wear, and they could serve as a valuable alternative.
Halina Mańczak M.D., Ph.D. received her doctoral degree from K. Marcinkowski University of Medical Sciences, Poznań, Poland. She received her Specialist in Ophthalmology and Ph.D. degrees from the same University.
She completed the “Intensive Course in Contact Lens Fitting” at the Institute of Optometry (London, England), followed by a one-year postgraduate residency program in contact lenses and education at the University of Alabama at Birmingham, School of Optometry, USA.
A recipient of the Polish Contact Lens Society’s “Cristal Lens Award” for achievements in the contact lens area, she has presented at conferences in Europe and in the United States, lectured at Universities in the USA and published in the fields of optometry, ophthalmology and contact lenses. She is also is an honorary member of Polish Contact Lens Society, a member of the Contact Lens Section of PTO, a member of ECLSO, and a member and former vice president of the European Chapter of IACLE, where she is now a member of the regional council of the Europe/Africa-Middle East region.
Over the past 20 years she has taught contact lens courses at K. Marcinkowski University of Medical Sciences, Poznań, Poland. Currently she runs a contact lens practice that specializes in keratoconus and other corneal deformations. She won the BCLA (England) 2010 and GSLS (USA) 2012 photographic competitions and the e-poster competition at ECLSO 2011.