“Specialty Contact Lens Grand Rounds: The Decision-Making Process“
Drs. Tiffany Andrzejewski and John Gelles
The presenters gave four very interesting and different cases including the following:
Case One: THE KERATOCONUS PATIENT
The Keratoconus Patient Case Gelles
Information: 35 y/o female referred for corneal crosslinking. She did not realize she had keratoconus and had wearing glasses her entire life. Had moderate-severe KCN 55.9/59.4 central cone IS ratio OD 12D. OS 15.3. Difference from top to bottom very significant. Refraction: OD: Pl – 4.00 x 090 OS: Pl – 5.50 x 090. Diagnosed with a large amount of coma, trefoil and spherical aberration.
What to do?
Scleral lenses good option; dispense & she says she is looking through a fishbowl . . sees 20/20-
Two Options:
- Custom soft lenses which can minimize the aberrations
- Scleral lenses
PEARLS
Scleral lenses are not always the answer
Selection Considerations
- Refraction: if better than 20/30 consider soft
- Rigid lens OR: if patient isn’t enthusiastic about this visual result, think soft
- Topography: if ≥ 10D of asymmetry, consider a scleral
Custom Soft Lenses
About the Lens:
- Made to order
- Soft Material
- Diameter: 14.5 – 16mm
- Refractive cyl ≥ 2.25D: variable thickness to mask irregularityPseudo-rigidity (0.3 – 0.6mm)
Fitting Goal
- Fit to align with light apical touch
- No edge lift
- < .5mm of movement
- Rotationally stable
Corneal Surface High Order Aberrations & Rigid Contact Lenses
- Anterior and posterior corneal aberrations are compensatory in keratoconus; they tend to cancel out
- Rigid lenses mask the anterior corneal aberrations still revealing the posterior aberrations
- Soft lenses drape to the anterior cornea maintaining the compensatory or cancelling out of aberrations simulating the no lens situation
Goal in this Case is to Reduce Residual HOA
Process:
- Scleral lens fit
- Wavefront Aberrometry measured with contact lens worn to collect HOA data of entire eye
- Compensatory optics are manufactured onto the front surface of the scleral lens; optics are totally custom to each individual eye
Well established as a viable option in the literature; as much as a two line increase in visual acuity and 60+ % reduction in HOA. Patient was successful with this modality.
Case Two: CORNEAL TRANSPLANT PATIENT
Information: 25 y/o male; history of keratoconus OS > OD; PK 6 months ago. Has never worn a contact lens. Chief Complaint: blurred vision OS > OD; OS vision much improved Post PK OS. Refraction: OD: -1.50 + 1.50 x 106 20/25. OS: -1.25 + 2.75 x 023 20/100. Irregularity on topography OS > OD
Corneal Graft Considerations
- Patient History
- Previous CL history: none
- Environment: he is a roofer working in a dusty environment
- Dexterity
- Eyelid anatomy: a very small fissure that might make scleral lenses more challenging
- Post-Op Corneal Status
- Epithelial integrity/stromal clarity/endothelial viability: all good
- Pre-existing neovascularization
- Presence of sutures
- Altered Corneal Topography
- Graft profile: Oblate vs. Prolate
- Ocular Medications: Is on glaucoma medications
- New graft vs. old graft
- Decrease in endothelial cell density due to successful transplantation
- Endothelial function compromised
- Acute corneal response . . . typically not worried with a new graft with an old graft you have to worry about edema/foggy edema/increased IOP; if 5% increase in corneal thickness could be of concern
Scleral Lenses and Corneal Edema
- Documented in compromised corneas; pachometry beneficial; carefully monitor
- Debated effect in normal corneas; clinical significance and long-term effect
- How to relieve? Material Dk, lens thickness, corneal clearance, channels, and fenestration?
Solution to Case
- Fit corneal GP
- Light feather touch but no harsh mid-peripheral touch on sutures
- 3 years later running suture changed . . . so much asymmetry that sclerals were fit
Post-Transplant Fitting Strategies
- Corneal GP is design of choice: delivers more oxygen to the cornea which is critical
- Choose initial BCR using the average K value 3mm from the center or overall average K
- Start with larger diameter (10 – 10.5mm) to minimize graft-host interface interaction
- OZD needs to be larger than average because of the graft (approximately 8mm)
- There are a number of commercial post-graft designs – try one! Follow their fitting guide.
- Guided = divided with balance of 1/3 touch and 2/3 clearance to evenly support the contact lens among 3 regions.
- Use a hyper Dk material (100+)
- Reverse Geometry – good for vaulting the mid-peripheral knee of an oblate graft
- Consider piggyback, hybrid, or scleral designs if the lens won’t center or is unstable.
If Sclerals
- Be cognizant of tear layer reservoir
- Hyper Dk material
Case Three: Keratoconus Patient + INTACS + Corneal Crosslinking
Information: 22 y/o male diagnosed with keratoconus in 2013. Poor vision OD > OS. Epi-On CXL OU 12/2013; INTACS OU 4/2017. Unaided VA: 20/400 OD; 20/30 OS. Refraction: OD: -2.25 + 1.50 x 159 20/60; OS: -0.75 + 1.00 x 030 20/25. Topography: small central cone due to INTACS.
Corneal GPs not recommended due to impact on cornea: consider soft to start.
Post-CXL Fitting Considerations
- No contact lens wear until after the re-epithelialization
- Corneal remodeling occurs during the first few months; wait for stabilization (1 – 2 months). This is more pertinent in lenses that rest directly on the cornea (GPs/hybrids). Scleral lens fitting/resumption can occur sooner
- Decreased corneal sensitivity = better tolerance of corneal GPs
- Depending on the flattening effect, the BCR and/or power may need to be adjusted.
- Initiation of the fit can occur after 1 – 2 weeks for epi-on CXK versus 1 – months for epi-off
Post-INTACs Fitting Considerations
- A little more challenging than post-CXL due to the changes in corneal shape necessitating a 3 month waiting period prior to contact lens fitting
- INTACS = increased elevation directly above the rings with flattening adjacent:
- Mid-size OAD to aid in centration
- Flatter mid-peripheral/peripheral curve necessary to avoid corneal binding
- Avoid chafing on ring segments
- Often results in an oblate cornea
- Piggybacking & sclerals can be great options
Patient had failed with corneal GPs and piggyback and was successfully fit with hybrids
Case Four: POST-RK PATIENT WITH DRYNESS
Information: 55 y/o female dissatisfied with vision in glasses; unable to tolerate GP or soft contact lenses anymore. Chief Complaint: glare/haloes at night, vision fluctuates AM to PM; poor vision with soft toric lenses; poor comfort with GP lenses; eyes are dry but wants to wear contact lenses. Ocular History: RK OD; RK + AK OS in 1995; dry eyes. Ocular Medications: xiiadra bid, thera tears q3-4hrs, Systane gel qhs.
Recommendation
Sclerals due to dryness and shifts and variation in refraction and topography
Advantages
- Fully vault the cornea and avoid spectacle blur
- Minimizes visual/refractive fluctuations
- Helps with dry eyes
But be careful as sclerals can induce hypoxia and lens suction can cause incisional gaping
Fitting Pearls
- If incisional neovascularization, take photos to document and monitor
- Consider oblate design to avoid over-vault
- Control the fluid reservoir vault to maximize oxygen
- Choose hyper Dk lens material
- Remove the lens YOURSELF every visit to check for suction and evaluate the ocular surface
- Final Outcome: after successful fitting of a scleral lens the following information was provided and a scleral multifocal design with decentered optics was ordered and ultimately was successful:
- Eye dominance
- Pupil size in normal and dim illumination
- Add power
PEARL: Importance of performing over-topography over a scleral lens to determine the position of the optical center relative to the pupillary axis. This is especially for determining the decentration necessary in a multifocal. Any decentration not compensated for induces COMA. This makes for another strong argument for wavefront-guided scleral lens designs.