What Is Your Impression?
Lynette Johns OD FAAO FSLS FBLCA
With so much attention on the clearance over the corneal apex and limbus when fitting scleral lenses for ectatic corneas, we must equally evaluate the landing zone of the scleral lens. After all, the sclera is what we are fitting! Sadly, this case represents an ocular health risk of scleral lenses: impingement-induced conjunctival hypertrophy. Fortunately, by refitting the patient with a different landing zone, the conjunctival hypertrophy resolved.
A 44-year-old man with a history of pellucid marginal degeneration OU wearing scleral lenses returned after four years and complained of severe pain OD at the end of wearing time. He described the pain as worsening with increasing wearing time; however, because he was so dependent on the lenses, he refused to reduce the wearing time. After long hours of wear (greater than 12 hours), he was very uncomfortable the next morning immediately after application. Entering acuity was 20/30+2 OD and 20/30+1 OS. He was happy with the visual acuity, but the discomfort prompted his return visit.
Figure A (below) shows the presentation of the right lens after 6 hours of wear. There was sectoral infero-nasal injection leading to a gelatinous tissue folding over the surface of the lens edge. There was mild blanching at the edge of the lens as well.
Figure B (below) shows the right eye without the lens. There was conjunctival staining with an elevated, almost nodular, ridge. The injection remained after the lens was removed. The specifications of the lens were 17.5 mm diameter, 4.75 mm sagittal height, 7.7 mm base curve, -8.25 D power, and the peripheral edge approximated at 13.5 mm radius without peripheral toricity.
He was refit into a 19.5 mm diameter lens, 5.00 mm sagittal height, 7.9 mm base curve, -7.75 D power, and the peripheral edge approximated at 16.0 mm radius with peripheral toricity of 0.65 mm. He obtained 20/20-2 vision. The patient appreciated the improved comfort, and the injection subsided after consistent wear. A year later, there was no injection, nor conjunctival abnormalities (unfortunately not photodocumented). Average wearing time was reported to be all waking hours without discomfort.
Impingement (according to this author) occurs when the very edge digs into the conjunctival tissue; blanching may or may not be observed. Compression causes conjunctival blanching that can be observed in any sector of the landing zone or even circumferentially. If it is seen at the edge of the lens, compression and impingement are occurring together. Impingement will leave behind arcuate staining as shown in this case, and over time, it may hypertrophy. If any arcuate staining is observed initially at a fitting assessment, it can easily be rectified by loosening the edge of the lens either 360 degrees around, with a toric periphery, or in quadrants depending on what is observed on the eye. If there is elevated hypertrophy, a diameter change may be required either to fit over the hypertrophy by increasing the diameter or by decreasing the diameter and fitting inside of the elevation.
Patients who have been challenging to fit through the years may be easily lost to follow-up once they are fit with a scleral lens. They experience the great vision and comfort and think that they are “fixed.” It is our obligation to stress the importance of routine follow-up visits with our scleral lens patients. Complications may occur over time, and early intervention can improve the comfort and vision to ensure long-term success.
Lynette Johns is an adjunct assistant professor and clinical attending in contact lenses at the New England College of Optometry.
She was formerly the senior optometrist at the Boston Foundation for Sight where she exclusively fit scleral lenses and managed complex corneal disease.
She is a fellow of the American Academy of Optometry and Scleral Lens Education Society as well as a fellow of the BCLA. She is a clinical and educational consultant to the GP and specialty soft lens division of Bausch + Lomb.