Abstract
Purpose
The objective of this series is to report the early post-operative visual outcomes of a novel triple procedure utilizing Descemet membrane endothelial keratoplasty (DMEK) plus light adjustable lens (LAL) in two patients (four eyes).
Methods
Two patients with bilateral, visually significant cataracts and Fuchs’ dystrophy were selected for DMEK plus LAL triple procedure. Patient B also exhibited a high amount of preoperative astigmatism. Both patients desired spectacle independence and were initially targeted for monovision with the dominant eye corrected for distance and the nondominant eye corrected for near. Best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), and manifest refraction were recorded at each postoperative appointment and light treatment.
Results
In the early post-operative course, Patient A chose to pursue binocular distance correction instead of monovision. This was adjusted for accordingly using the LAL. Following final lock-in, Patient A had a distance UCVA of 20/15 in the right eye (OD) and a distance UCVA of 20/20 in the left eye (OS). Patient B was targeted for monovision. After final lock-in, Patient B had a distance UCVA of 20/15 in the dominant eye (OD) and a near UCVA of Jaeger No. 1+ in the nondominant eye (OS).
Conclusions and Importance
The first reported cases of DMEK plus LAL triple procedures achieved exceptional UCVA at the desired target. The post-operative customizability of the LAL allows for the achievement of excellent refractive outcomes after DMEK, even in patients with significant astigmatism and in patients who change their mind regarding refractive target.
Highlights
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Two patients underwent a novel DMEK and Light Adjustable Lens (LAL) triple procedure.
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Refractive outcomes were 20/15 or 20/20 uncorrected distance visual acuity.
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A patient with −2 D astigmatism achieved 20/15 distance and Jaeger 1+ near monovision.
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The LAL allows for post-operative flexibility and customizability in DMEK triple procedures.
1
Introduction
Descemet Membrane Endothelial Keratoplasty (DMEK), first described by Dr. Gerrit Melles in 2006, is a partial thickness cornea transplant technique in which the corneal endothelium and Descemet’s membrane are transplanted. Fuchs’ dystrophy is the most common indication for corneal transplants. DMEK continues to gain popularity over its predecessor Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) due to better visual outcomes and increased patient satisfaction, , including in eyes with concurrent phacoemulsification and intraocular lens (IOL) implantation.
The aforementioned procedure in which DMEK is combined with phacoemulsification and IOL implantation has become known as DMEK triple or DMEK plus and has been described as safe and cost-effective for DMEK patients with concurrent cataract. , DMEK has been shown to accelerate cataract formation, so a triple procedure is sometimes recommended to avoid later need for reoperation, especially in those over 50 or those with a shallow anterior chamber. , A staged procedure, DMEK followed by cataract extraction at a later date once the cornea has stabilized, offers the best possible refractive outcome, but carries the risk of multiple intraocular procedures. Furthermore, staged procedures may shorten corneal graft viability as phacoemulsification is a known cause of endothelial cell loss.
Many variables influence the refractive outcome in both cataract extraction and DMEK. For example, DMEK is known to induce a hyperopic shift. Therefore, pre-operative lens selection in combined cases is unpredictable and limits refractive outcomes. This uncertainty is increased when the patient has preoperative astigmatism and/or the surgical goal of monovision. One promising method to improve refractive outcomes in DMEK triple procedures, especially for those with astigmatism or the goal of monovision, is use of the RXSight Light Adjustable Lens (LAL). Development of the LAL began in 2003. The lens consists of a photosensitive silicone material which allows for post-operative adjustment using directed ultraviolet (UV) light. The LAL allows for correction of residual myopic and hyperopic spherical error up to two diopters (D) and cylindrical error up to three diopters. These corrections may occur over several post-operative light treatments before the LAL is locked in to a final power.
The objective of this series is to report the early post-operative outcomes of a novel triple procedure utilizing DMEK plus LAL in two patients (four eyes).
2
Materials and methods
Patients were selected as candidates for DMEK plus LAL for the indication of Fuchs’ dystrophy and concurrent visually significant cataracts. Standard lens options and the possibility of staged procedures were offered. Both patients were highly motivated for spectacle independence. Given the lack of predictability with DMEK plus standard IOL and staged procedures, both patients elected for DMEK plus LAL. The surgical plan was to target both patients for monovision before correcting the residual postoperative refractive error with a digital light delivery device (DLDD).
Informed consent was obtained. Preoperatively, patients underwent examination for manifest refraction, Snellen best corrected visual acuity (BCVA) and uncorrected visual acuity (UCVA), brightness acuity testing (BAT), corneal corrected intraocular pressure (ccIOP), corneal topography, keratometry, and specular microscopy to determine endothelial cell counts. LAL powers were calculated using standard ocular biometry. Each patient was initially targeted for −0.5 D distance vision in their dominant eye and −1.25 or −1.5 D near vision in their nondominant eye. All targets were offset by −0.5 D from the desired outcome to account for postoperative hyperopic shift due to the optics of the corneal graft and posterior lens capsule.
Standard phacoemulsification and LAL implantation followed by a standardized DMEK procedure was performed as previously described by Terry et al. with the modification of a 2.8 mm incision which is required for the LAL cartridge. A 10-0 vicryl suture was placed through the main incision and removed at the one-week postoperative visit.
Patients were examined postoperatively at one day, one week, and two weeks. The first postoperative manifest refraction was recorded once the gas bubble had dissipated and the graft was completely attached. This was typically done at the one-week visit. If there was a need for rebubbling, anterior segment optical coherence tomography was performed. The patients returned for LAL adjustment and lock-in using a DLDD after a period of refractive stability. Refractive stability was defined as two consecutive similar refractions postoperatively. The DLDD protocol has been described in detail elsewhere. The target refraction entered into the DLDD was guided by a combination of the patient’s subjective manifest refraction and satisfaction.
3
Results
Baseline visual acuities, glare testing, and endothelial cell counts are summarized for both patients in Table 1 . Manifest refractions for both patients throughout the postoperative follow up, DLDD adjustments, and lock-in treatments are summarized in Table 2 .
| Patient A OD | Patient A OS | |
|---|---|---|
| UCVA | 20/20 -2 | 20/20 -1 |
| BCVA | 20/20 | 20/20 |
| BAT | 20/50 | 20/50 |
| Endothelial cell density (cells/mm 3 ) | 2358 | 2232 |
| Central corneal thickness (μm) | 584 | 589 |
| Patient B OD | Patient B OS | |
| UCVA | 20/40 | 20/60 |
| BCVA | 20/15 -2 | 20/15 -1 |
| BAT | 20/50 | 20/150 |
| Endothelial cell density (cells/mm 3 ) | 2262 | 2653 |
| Central corneal thickness (μm) | 571 | 566 |
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