Molded Scleral Lenses for a “Proud” Penetrating Keratoplasty Graft: Tom Arnold, OD, FSLS
Background
A fifty year-old African American male was referred for evaluation of EyePrintPRO scleral lenses. He had undergone penetrating keratoplasty in both eyes for keratoconus approximately twenty-five years prior. Over time his grafts had become so elevated that he was uncomfortable wearing a corneal gas permeable (GP) lens in the right eye and was completely unable to wear a left lens. He had previously tried hybrid lenses and sclerals with no success.
Test Procedures, Fitting/Refitting, Design, and Ordering
Visit #1: Comprehensive Examination
Entering Visual Acuities (current lens right eye, uncorrected left eye)
OD: 20/60
OS: Hand motion
Manifest Refraction
Unable
Intraocular Pressures (iCare)
OD: 10 mmHg
OS: 08 mmHg
Anterior Segment Evaluation
Corneas: Very elevated grafts OU; OS >> OD
Lenses: Grade 1+ nuclear sclerosis OU
HVID: 12.3 mm OD, 12.0 mm OS
Pentacam Tomography
Scleral Lens Fitting
Molds were taken of both eyes with the standard EyePrintPRO system (Figure 4). This involves filling a tray with ophthalmic grade polyvinylsiloxane material, waiting 50 seconds for it to begin to gel before inserted into the eye. The procedure is painless and requires no topical anesthetics. The tray is left in the eye for approximately three minutes so that the compound can set up to a completely solid state. However, it is not rigid and remains soft to the touch.
When good coverage of the cornea and surrounding sclera is achieved, the mold is then sent to the lab to be digitally scanned for lens fabrication (Figures 5a and 5b).
In order to evaluate the lens prescription, a rigid lens of a known base curve and power is inserted into the eye and an over-refraction is obtained. In this case we used a large diameter scleral lens (19.0 mm). Even with the maximum sagittal depth from the trial set, the lens still touched the left cornea.
Diagnostic lenses
OD: 8.00 BC/19.0 mm diameter/ +0.25 sphere/ over refraction -10.00 sphere 20/40
OS: 8.00 BC/19.0 mm diameter/ +0.25 sphere/ over refraction -12.00 -1.00 x 090 20/30
Initial Lens Order: EyePrintPRO
OD: 6.45 BC/ 17.6 mm diameter/-18.75 sphere/ CT 300 µm/ Hydra-PEG
OS: 6.87 BC/17.5 mm diameter/ -17.62 sphere/ CT 300 µm/ Hydra- PEG
Patient Consultation and Education
Visit #2: Dispense Appointment
Visual Acuity with EyePrintPRO lenses
OD: 20/70, over-refraction -2.25 DS (20/25+)
OS: 20/20, over-refraction Plano
Slit Lamp Evaluation
OD: Slight decentration, otherwise appropriate corneal clearance and edge alignment
OS: Edge compression with blanching at 11:00 and 5:00, otherwise appropriate corneal clearance
Care Education
Solutions Recommended: Lacripure sterile saline and Unique pH Conditioning Solution
Follow-up Care and Final Outcome
Visit #3: One Week Follow-up
The patient returned within one week for a progress check with a complaint that the vision in the right eye was still blurry, and the left eye had clear vision but that slight soreness was experienced upon lens removal.
Visual Acuity with EyePrintPRO lenses
OD: 20/60, over-refraction -1.25 DS (20/20)
OS: 20/20, over-refraction -0.50 DS (20/20, but “sharper”)
Slit Lamp Evaluation
OD: slight touch of cornea nasally
OS: lens tight 4:00- 8:00
Both lenses easily removed in office and no excessive suction noted.
Modifications for Next Order
OD: Increase mid-peripheral clearance and incorporate over-refraction
OS: Flatten haptic where blanching is occurring and incorporate over-refraction
Second Lens Order: EyePrintPRO
OD 6.940 BC/ 17.6 mm diameter/ -16.25 sphere/ CT 300 µm/ Hydra-PEG
OS 6.871 BC/ 17.6 mm diameter/ -18.12 sphere/ CT 300 µm/ Hydra-PEG
Visit #4: Dispense of Second Lens Order
The patient returned two weeks later for a dispense of the new pair of lenses. Visual acuity was 20/20 OD and 20/25 OS and the new lenses fit great OU. The patient was instructed to return in three weeks for a progress check.
Visit #5: Three Week Follow-Up
The patient returned three weeks later reporting good vision in both eyes, but that the left lens fogs occasionally. His wear time at that visit was seven hours, and average wear time was 8-9 hours per day. Visual acuity was 20/20 in each eye. Anterior segment OCT showed 211 µm central clearance OD and 77 µm central clearance OS. Slit lamp evaluation showed a good fit with alignment in all quadrants OD, but light touch on the superior limbus and mild inferior superficial punctate keratitis OS. The patient was instructed to continue with the current right lens. For the left eye, the patient was instructed to return to the previous lens and monitor comfort. If comfort improves, will remake lens utilizing most recent power.
After about three weeks the patient communicated that the previous left lens was more comfortable, so a new left lens was ordered with the updated prescription.
Discussion/Alternative Management Options
This challenging case demonstrates the benefit of having impression molding as a lens option. The advanced ectasia created by these aging keratoplasties made fitting with a standard scleral design extremely difficult. Utilizing a trial lens method of fitting, even with Scheimpflug tomography, would have required many more visits and possible lens exchanges. As it was, two lenses were required for the right eye and three for the left eye. It was very gratifying to achieve 20/20 vision in both eyes with a wearing time adequate for the patient to remain at his job full time.
References
- Bennett, E.S. Areas of Potential Growth. GP Annual Report, Contact Lens Spectrum 2014;29(10):20-30.
- EyePrint Prosthetics Announces Clinical Outcomes Achieved with EyePrint Pro. Eyewire News. April 2018.
- Eiden, B. Advanced Technologies in Corneal and Anterior Segment Shape Analysis for Contact Lens Design”. Research Review. Contact Lenses Today. April 2014.
- Nguyen M.T.B., Thakar V., Chan C. EyePrint Pro Therapeutic Scleral Contact Lens: Indications and Outcomes. Can J. Ophthalmol. 2018; 53:65-69.
Back to Table of Contents