LEARNING METHOD AND MEDIUM
This educational activity consists of a written article and 20 study questions. The participant should, in order, read the Activity Description listed at the beginning of this activity, read the material, answer all questions in the post test, and then complete the Activity Evaluation/Credit Request form. To receive credit for this activity, please follow the instructions provided below in the section titled To Obtain CE Credit. This educational activity should take a maximum of 2 hours to complete.
This continuing education (CE) activity captures key statistics and insights from contributing faculty.
The goal of this article is to provide an overview of six separate challenging contact lens cases, all fit with a different type of lens design.
This educational activity is intended for optometrists, contact lens specialists, and other eyecare professionals.
ACCREDITATION DESIGNATION STATEMENT
This course is COPE approved for 2 hours of CE credit.
COPE Course ID: 89605-CL
Roxanne Achong-Coan, OD, has received remuneration from Essilor Contact Lenses and is a consultant for Coopervision. Jennifer Harthan, OD,has received remuneration from CooperVision, Euclid, International Keratoconus Academy, Johnson & Johnson Vision, and Metro Optics, and has received research grants from Art Optical, Bausch + Lomb, Contamac, Ocular Therapeutix, Metro Optics, and SynergEyes. Tiffany Andrzejewski, OD, has received remuneration from Bausch + Lomb Specialty Vision Products, Blanchard, Essilor Contact Lenses, Ocular Therapeutix, and SynergEyes. Heidi Miller, OD, is a speaker or consultant to Alcon, Bausch + Lomb, Valley Contax, and Tarsus and has received non-COPE CE lecture or authorship honoraria from the Scleral Lens Education Society and the Sacramento Valley Optometric Society. Susan Resnick, OD,is a speaker or consultant to Alcon, Bausch + Lomb, Johnson & Johnson, and Sight Sciences. Mile Brujic, OD, has received remuneration from Apellis, ABB Optical, Aldeyra, Allergan, Art Optical, Avellino, Bausch + Lomb Health, Contamac, CSEye, Dompé, Horizon Therapeutics, Notal Vision, Quidel, Radius XR, RVL, Sun Pharma, Tarsus, Visus, Visionix, Walman Optical, Thea, Viatris, and ZeaVision. He has an educational grant or contract with Johnson & Johnson Vision Care, Dompé, Lumenis, Thea, and Trukera.
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1. That the relationships/affiliations noted will not bias or otherwise influence their involvement in this activity;
2. That practice recommendations given relevant to the companies with whom they have relationships/affiliations will be supported by the best available evidence or, absent evidence, will be consistent with generally accepted medical practice;
3. That all reasonable clinical alternatives will be discussed when making practice recommendations.
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Release date: February 1, 2023
Expiration Date: January 31, 2027
CASE 1: KERATOCONUS PATIENT MANAGED WITH CUSTOM SOFT LENSES
History A 35-year-old African American male who worked outdoors in construction presented to the clinic with a history of keratoconus. He was fitted with soft contact lenses in both eyes at a different facility but had poor vision.
The clinic then attempted to fit him in GP contact lenses, but he discontinued them due to poor comfort and stability and the lenses kept popping out with eye movement. He was then referred to our clinic because they could not fit him with contact lenses successfully. He did have a history of allergies and was otherwise healthy.
His manifest refraction was:
+3.00 –7.50 x 060 DVA 20/70 OD
+2.75 –6.50 x 135 DVA 20/30 OS
Slit lamp examination showed that he had floppy eyelid syndrome, Vogt’s striae, and pingueculas nasal and temporal in both eyes, but there was no corneal scarring.
Figures 1 and 2 show the corneal topographies of each eye.
Corneal topography confirmed the diagnosis of keratoconus in both eyes. One method used to determine whether to fit a corneal GP lens or a scleral lens is by using an elevation map. According to Zheng and colleagues, if the elevation difference is less than 350µm, a corneal GP lens would be approximately an 8 out of 10 success; if the elevation difference is greater, the asymmetry of the eye is too extreme, and the corneal GP lens will be rocking or tilting excessively on the irregular cornea.1 The elevation difference between the right and left eyes was 818µm and 668µm, respectively. Therefore, a scleral lens was chosen.
Lens Evaluation, Fitting, and Follow-Up The patient was fit with a scleral contact lens to improve vision and the following parameters were ordered.
Visual acuity was measured at 20/20 in each eye. There was approximately 300 microns of central clearance, good limbal clearance, and no blanching, with slight impingement at 3 and 9 o’clock where the pingueculas were located.
For the first two weeks he was able to wear the lenses for no more than six hours, as he experienced redness in the interpalpebral area where his pingueculas were located. Notches were placed in the scleral lenses where the pingueculas were present, but he still experienced redness around the pingueculas after four hours of wear.
Therefore, the patient was refitted with a soft toric custom contact lens. The initial lenses were unsuccessful because the peripheral lens parameters could not be changed and he experienced edge fluting. Therefore, soft toric custom lenses were the choice for the low cones. The other advantage of fitting this patient with soft toric custom lenses is that the material consists of silicone hydrogel material and the peripheries can be ordered flat or steep. Using the tangential maps with the polar grid (as shown in Figure 3) and the data within the 5mm ring, the calculator recommended a 9.2mm base curve for the right eye and 9.4mm for the left eye.
When the lenses were received, the right lens showed some fluting on the edge, and the left lens was slightly loose. Therefore, the peripheries were adjusted, and lenses were ordered with a final vision correction of 20/30 OD and 20/20 OS.
The lenses were both centered and stable, with 1mm of movement and no edge fluting. The patient could wear the lenses long term without any issues. He also did not develop redness or irritation around the pingueculas.
Clinical Pearls Soft lenses are still an excellent choice for mild to moderate keratoconus patients, especially when the anatomy past the limbal area becomes highly irregular. These lenses can easily drape over these irregularities and provide excellent comfort and satisfactory, stable vision.
Hybrid lenses are another excellent choice for this patient, as he will have better vision with the GP lens optics and the comfort of a soft contact lens skirt that will fit over the irregularities of the conjunctiva. The new generation of hybrid lenses also provide excellent oxygen transmissibility to the cornea due to the higher-Dk materials.
As scleral profilometry has improved, it is now possible to measure the size and depth of any irregular tissue growths on the conjunctival surface. Channels and notches can be added with certain brands of scleral lenses. The shape of the sclera is asymmetrical as discovered with new technologies including Scheimpflug imaging, scleral topography, and optical coherence tomography.
DeNaeyer and colleagues found that only 5.7% will be successfully fit with a spherical haptic and 28.7% with a toric haptic; the remaining were asymmetric, requiring a back surface, quadrant, or custom haptic.2 If the conjunctiva is highly irregular, then a free-form lens can be designed based on scleral profilometry, or an eye impression can be obtained.
CASE 2: CORNEAL GP FITTING STATUS POST PENETRATING KERATOPLASTY
History An 85-year-old female presented for a contact lens fitting status post penetrating keratoplasty (PKP) of her left cornea. The patient had been diagnosed with keratoconus more than 40 years prior, corneal hydrops in her left eye 20 years prior, and had a long history of successful corneal GP contact lens wear. She underwent cataract surgery in both eyes one year prior with no complications.
She reported distorted vision in her left eye without correction and wanted to wear GPs in both eyes again to be able to independently drive. She was not able to return to wearing her previous left GP lens, as her corneal shape had changed s/p PKP. Her visual acuity through her habitual GP was 20/25- OD. Her uncorrected visual acuity was 20/200 OS, pinhole 20/40 OS. Subjective refraction was –7.75 –3.25 x 040 OD (20/60) and –12.00 –3.00 x 150 OS (20/60).
Upon slit lamp examination, the lids of both eyes showed 1+ meibomian gland dysfunction (MGD). The right cornea had apical thinning and steepening, and the left cornea had a clear graft, a running suture, and no evidence of graft rejection. She had 1+ inferior punctate epithelial staining and a reduced tear breakup time (TBUT) in each eye.
Corneal tomography was performed to determine the size, shape, and severity of the corneal ectasia OD and help determine which type of contact lens design would be most appropriate for the patient, secondary to the shape and position of the corneal graft OS. The right cornea had K readings of 52.0D/58.1D @ 135 and pachymetry of 388 microns (Figure 4). The left cornea had K readings of 45.0D/48.2D @ 31.3 and pachymetry of 523 microns (Figure 5). The patient was fit with a reverse-geometry GP contact lens OS to avoid mechanical disruption from the lens touching the cornea over the graft-host junction, as the corneal shape was more oblate s/p PKP.
Lens Evaluation, Fitting, and Follow-Up The initial diagnostic GP contact lens parameters were based on the manufacturer’s fitting guide.
Initial Diagnostic Contact Lens Parameters
The initial GP for the right eye demonstrated apical alignment, mid-peripheral bearing, and high edge lift, particularly inferiorly at the 6 o’clock position. The patient reported that she could feel the lens upon blink, and it was moving approximately 1.5mm.
This GP design was selected based on the inferior position of the cone and for the ability to modify the peripheral curve system. A steeper lens edge was ordered. Additionally, due to the higher edge lift at the 6 o’clock position, the inferior quadrant was steepened to improve comfort and stability.
The initial GP lens for the left eye demonstrated apical pooling, mid-peripheral bearing, and 360˚ edge. The patient reported that she could feel the lens upon blinking. The lens was decentered temporally and moving approximately 1.5mm.
This GP design was selected based on the oblate shape of the graft and the ability to modify the reverse curve to avoid mechanical disruption of the graft-host junction. The central base curve was ordered flatter, the reverse curve was ordered steeper, the overall diameter was ordered larger, and the edge was steepened.
The patient was instructed to disinfect her contact lenses nightly with either an approved hydrogen peroxide or multipurpose solution system. She was also prescribed preservative-free artificial tears to use three times daily and ointment to use at night in both eyes. She reported that the lenses were comfortable and that she had been successfully wearing them 14 hours per day.
Final Contact Lens Parameters
Clinical Pearls Contact lenses are often required following PKP, not only to enhance vision but also for therapeutic purposes.3 When selecting an initial lens design post PKP, practitioners should identify the amount and type of corneal astigmatism present, comorbid ocular and systemic diseases, location, shape (prolate or oblate) and size of the graft, elevation between the host and donor cornea, health of endothelial cells, and history of previous graft rejection.3-5
GP contact lenses are a great option for patients who are status post PKP, as they provide improved vision, correct for high amounts of irregular astigmatism, are highly oxygen permeable, and have a low risk of infection and complications.3,5 Reverse-geometry GP designs are particularly beneficial for patients who have oblate grafts, as they can improve centration over the graft-host junction.
CASE 3: POST-LASIK ECTASIA MANAGED WITH HYBRID LENSES
History A 34-year-old male patient diagnosed with post-laser-assisted in situ keratomileusis (LASIK) ectasia OD > OS presented for a scleral lens evaluation following corneal cross-linking (CXL) in 2015. He was suffering from poor vision exclusively in his right eye. His uncorrected vision was 20/200 OD and 20/30 OS.
He had previously tried and failed with corneal GP lenses and piggybacking, despite achieving 20/30 vision, due to issues with lens comfort. The patient was fit with a scleral contact lens (ScCL), which improved his vision to 20/30 OD and gave him great all-day comfort.
Throughout the fitting process, the patient reported considerable foggy vision, starting within a few hours of wear. Initially, this fogginess was due to haptic misalignment of the lens, as there was evidence of debris in the fluid reservoir under the ScCL along with fluorescein seeping under the lens along the flat meridian of the haptic (Figure 6).
However, once the haptics were adequately aligned, the fit of the ScCL was optimized, minimizing any tear exchange under the lens; the patient’s symptoms improved but did not resolve; he concurrently had MGD (Figure 7) and a very oily tear film that made the anterior surface of his ScCL look like an oil slick on the surface (Figure 8).
After two years of exhausting all options, including various contact lens solutions, polyethylene glycol (PEG) treatment, and multiple thermopulsation treatments for MGD, the patient presented for a refit, wanting to try a different contact lens modality after his scleral lens broke.
Lens Evaluation, Fitting, and Follow-Up The patient was diagnostically fit into a hybrid lens. The lens cleared the cornea centrally, exhibited light touch in the inner landing zone, bearing in the outer landing zone of the soft skirt, and perceptible movement with blinking after several hours of wear. Upon removal of the lens from the eye, there were no signs of epithelial disruption, only a light impression ring from the lens (Figure 9) and no signs of rebound conjunctival injection.
The final lens parameters were: 250 micron vault, 14.6mm diameter, flat skirt, –7.50D power. A plasma treatment was added to the surface of the lens to enhance comfort and surface lubricity. The patient’s vision improved to 20/25 with the lens and he reported that, although he still felt like his vision became foggy after long hours on the computer, it was significantly better than what he had experienced previously with his scleral lenses.
The patient continues to undergo thermopulsation treatments for his MGD every six months. He continues at-home maintenance with omega-3 supplementation and hot compresses, and he finds that his vision is very manageable with the change to a hybrid lens and a six-month lens replacement schedule.
1) Hybrids are a viable option for those patients who have mild to moderate central corneal irregularities. Their clinical success can be more limited in patients who have more peripheral irregularities.6
2) Like scleral lenses, hybrids can have a prolate or oblate design. Therefore, it is important to look at the corneal profile before choosing the most appropriate design.
3) Hybrids can result in improved lens comfort and tolerability,7 and one study demonstrated better vision in comparison8to a corneal GP.
4) The soft skirt of a hybrid lens adapts to the shape of the sclera to improve alignment and, in some cases, reduce lens reservoir fogging.
5) A hybrid also can result in less anterior surface fogging and deposition because the GP portion of a hybrid (8.5mm) makes up a significantly smaller surface area that optically impacts vision compared to that of a scleral lens (14mm+).
CASE 4: STEVENS-JOHNSON SYNDROME OCULAR SURFACE DISEASE MANAGEMENT WITH SCLERAL LENSES
History An 8-year-old female was referred for a scleral contact lens evaluation due to severe dry eyes and light sensitivity. She had a history of Stevens-Johnson syndrome since 2013, with ocular involvement requiring amniotic membrane transplants bilaterally.
She subsequently developed chronic trichiasis and had been experiencing worsening ocular surface discomfort and light sensitivity in both eyes over the past few years. The light sensitivity was so severe that she was constantly covering her eyes at school. She had accommodations at school, consisting of sitting in a dark corner of the classroom due to her intolerance of classroom lighting.
The patient’s parents had been instilling preservative-free artificial tears two times per day in each eye and using ophthalmic ointment at bedtime. The patient was resistant to these treatments, so the parents were unable to lubricate her eyes more often than this. The patient had seen an oculoplastic specialist to consider electroepilation. However, the parents preferred that she have manual epilation to avoid any anesthesia-related procedure.
On initial examination in our office, uncorrected visual acuity was 20/150 OD and 20/100 OS. Visual acuity testing was limited by the patient’s light sensitivity and lack of cooperation. External examination was notable for reactive ptosis bilaterally. Slit-lamp examination of the right eye showed an irregular inferior lid margin with several central trichiatic lashes in the lower eyelid, a few contacting the cornea. On the left side, the lid margins were irregular with central trichiatic eyelashes on the lower lid that were not touching the cornea.
The conjunctiva and sclera on both the right and left sides showed 2+ diffuse injection with mild chemosis. The cornea on the right side had confluent punctate epithelial erosions inferiorly and centrally, with peripheral neovascularization inferiorly. The cornea on the left side showed a smaller patch of confluent punctate epithelial erosions inferiorly with peripheral neovascularization, but was fairly clear centrally (Figure 10).
Given the clinical presentation, it was decided to fit the patient with a smaller diameter scleral lens to provide ocular surface protection and ease of application/removal of lenses. Hydrogen peroxide solution was advised for nightly disinfection. Sodium chloride 0.9% solution was prescribed for rinsing and filling scleral lenses.
Lens Evaluation, Fitting, and Follow-Up
OD: Scleral OAD 15.4mm, BCR: 8.04mm, power –2.00D, 4000 sag, std, 250µm, Optimum Extra
OS: Scleral OAD 15.4mm, BCR: 8.04mm, power –2.00D, 4000 sag, std, 250µm, Optimum Extra
OD: +1.25 20/80
OS: +0.50 20/80
Contact Lens Evaluation: adequate central and limbal clearance with tight landing zone 360˚.
During the fitting, it was necessary to instill proparacaine prior to applying the lenses in office. A fixation target was placed on the floor. A plunger with suction was necessary to ensure the lens did not fall off the plunger if the patient squeezed her eyelids. It took several attempts to achieve application. However, the patient became more comfortable once she experienced a few lenses on her eye.
New lenses were ordered incorporating the over-refraction and a looser landing zone. Central clearance and limbal clearance were kept the same. The patient and her family were advised to observe application and removal videos prior to the next training and dispensation follow-up appointment.
The patient returned for several follow-up evaluations to adjust lens parameters, recheck visual acuity, and provide additional training on handling. She was able to remove the lenses successfully, which was important in case she needed to remove them at school. Her vision gradually improved as her corneal health improved over time.
Once the contact lenses were working well for her, she was followed every six months to monitor the health of the cornea. This was also an opportunity to review lid hygiene and lens care and evaluate whether lash epilation was necessary.
At the patient’s one-year follow-up evaluation, she reported great overall eye comfort and no longer experienced photophobia. She no longer required special accommodations at school and could join her peers in the classroom. Her visual acuity with correction was 20/20 in both eyes. She was using preservative-free tears four times per day in both eyes and nighttime gel before bed in both eyes.
Clinical Pearls Ocular surface disease management at any age is challenging. It is important to recognize that fitting scleral lenses in pediatric patients is possible. Office visits will require more time, patience, and patient education. However, these lenses can be life-changing for the patient. It is a good idea to begin with a smaller-diameter scleral lens to make application and removal easier for the patient.
Have the patient practice holding their eyelids and touching their conjunctiva at home over the next few weeks while they are waiting for their first ordered lenses to arrive. Also, instruct the patient to watch patient education videos ahead of time so expectations are set prior to their follow-up visit. It may take a few training visits for the patient to leave with the lenses, but that is acceptable. The key is to be supportive and remain positive at every encounter.
CASE 5: TRANSLATING BIFOCAL GP LENSES IN A PSEUDOPHAKIC PATIENT
History A 70-year-old female presented for contact lens evaluation and fitting one month after undergoing an uneventful bilateral lens extraction/posterior chamber intraocular lens (IOL) implantation. Monofocal IOLs were implanted with a target of full distance correction OD and OS.
She had been a successful wearer of GP lenses in a monovision modality (for the correction of high myopia and presbyopia) for 15 years. She was subsequently refit into aspheric multifocal (simultaneous vision) lenses when the level of correction needed for reading became too disruptive to her binocular comfort and depth perception. She had retired prior to her most recent fitting and expressed that she no longer had a great need for computer or intermediate vision and was seeking good distance vision and binocularity at near for a working distance of 15 inches.
Lens Evaluation, Fitting, and Follow-Up
Contact Lens Fitting
Contact lens fitting with translating (segmented) GP bifocal lenses was initiated for the following reasons:
1) The patient had been a very successful long-time wearer of GP lenses.
2) Historically she was a high myope with a habitual reading distance of less than 16 inches.
3) She had no significant need for intermediate or computer vision.
4) She desired binocular correction (i.e., no “monovision”).
Based on the empirical data, the following fluoro-silicone/acrylate lenses were ordered and dispensed:
Lens Fit Evaluation
Lens care and handling were carefully reviewed and the patient was cautioned against exposing the lenses to tap water, bathing, and swimming. A multipurpose GP solution was prescribed with instructions to rub before storing and to rinse with multipurpose soft lens solution or unpreserved unit dose saline.
Follow-up/Final Disposition The patient presented for two follow-up visits within a six-month period. She was very pleased with vision and comfort. There was no change in lens performance, and her corneas remained clear.
Clinical Pearls A presbyopic GP selection strategy is provided in Table 1. Translating GP bifocals are an excellent option for patients who have a high demand for near vision, such as this patient, who is pseudophakic corrected with monofocal IOLs and, therefore, an absolute presbyope.
CASE 6: FIXING TWO PROBLEMS WITH SCLERAL LENSES
History A 54-year-old female was referred to the office for a specialty lens secondary to peripheral corneal degeneration. Her cornea had substantial irregularities with peripheral corneal elevations OD and OS. Her best-corrected visual acuity with a standard phoropter refraction was 20/40 OD and 20/50 OS.
We discussed the options for vision correction with the patient. The peripheral corneal irregularities created some logistical challenges and limited our options for this patient. A corneal GP lens was going to be a challenge, as the edge would land in the peripheral corneal region, which contained the irregular elevations.
The surface irregularities ruled out soft lenses as an option. Hybrid lenses would have similar challenges compared to a corneal GP lens. A scleral lens would have the opportunity to vault over the cornea, including the irregular peripheral cornea, and ultimately provide a rigid optical surface to correct the patient’s vision. A scleral lens fit was initiated.
Fitting, Evaluation, and Follow-Up The patient was successfully fit with diagnostic lenses. The vision obtained with the diagnostic lenses and over-refraction was 20/20 OD and 20/20 OS. During the diagnostic fitting, the scleral lens was resting along the peripheral cornea 360˚ but more so nasally and temporally OD and OS. Lenses were ordered for the patient with appropriate landing zone and central corneal clearance. However, the scleral lens still was not clearing the peripheral nasal and temporal regions of the cornea (Figure 11).
The limbal clearance and peripheral corneal clearance regions of the lens were altered to increase the elevation of the lens above the peripheral corneal irregularities (Figure 12). It is critical to compensate for the central region of the lens when doing this. If the peripheral corneal regions of the scleral lens are being adjusted to elevate above peripheral corneal irregularities, it is important to reverse the curve of the scleral lens so that central corneal clearance of the lens is not excessive.
Most contemporary scleral lenses can be customized at a high level to provide us with the opportunity to improve the limbal and peripheral corneal regions in the lens. As can be seen in Figure 13 (and highlighted with the arrows), customizations around difficult landmarks can be achieved by changing the trajectory of the curves of the lens.
Beginning in the landing zone and moving proximally into the lens, a curve change that causes an elevation of the limbal region lifts the lens over the irregularity. A second change in the curve allows it to mimic the curve of the irregularity. Then, a third curve change assures that the central corneal clearance of the lens is adequate and not excessive (Figure 13).
After finalizing the fit, the patient’s lenses were ordered with multifocal lens power. The optics were offset nasally to optimally align it with the patient’s visual axis. The patient is currently wearing the contact lenses and is extremely happy with her vision. She rarely requires reading glasses.
Clinical Pearls Most contemporary scleral lenses can be customized at a high level to provide us the opportunity to improve the limbal and peripheral corneal regions in the lens.
1. Zheng F, Caroline P, Kojima R, André M, Lampa M. Corneal elevation differences and the initial selection of corneal and scleral contact lens. Poster presented at the 2015 Global Specialty Lens Symposium, Las Vegas. January 2015.
2. DeNaeyer G, Sanders DR, van der Worp E, Jedlicka J, Michaud L, Morrison S. Qualitative Assessment of Scleral Shape Patterns Using a New Wide Field Ocular Surface Elevation Topographer: The SSSG Study. J Cont Lens Res Sci. 2017 Nov;1:12-22.
3. Szczotka LB, Lindsay RG. Contact lens fitting following corneal graft surgery. Clin Exp Optom. 2003 Jul;86:244-249.
4. Lass JH, Sugar A, Benetz BA, et al. Endothelial cell density to predict graft failure after penetrating keratoplasty. Arch Ophthalmol. 2010 Jan;128;63-69.
5. Wietharn BE, Driebe WT. Fitting contact lenses for visual rehabilitation after penetrating keratoplasty. Eye Contact Lens. 2004 Jan;30:31-33.
6. Uçakhan ÖÖ, Yeşiltaş YS. Correction of irregular astigmatism with new-generation hybrid contact lenses. Eye Contact Lens. 2020 Mar;46:91-98.
7. Nau AC. A comparison of synergeyes versus traditional rigid gas permeable lens designs for patients with irregular corneas. Eye Contact Lens. 2008 Jul;34:198-200.
8. Hassani M, Jafarzadehpur E, Mirzajani A, Yekta A, Khabazkhoob M. A
comparison of the visual acuity outcome between Clearkone and RGP lenses. J Curr Ophthalmol. 2018 Mar;30:85-86.