May 2019

REFRACTIVE

Point/Counterpoint
Successful use of the KAMRA corneal inlay after cataract surgery


by Martin L. Fox, MD, Jeffrey Augustine, OD, and William Wiley, MD


KAMRA inlay at 280 micron corneal depth in patient with a monofocal IOL targeted for –0.75
Source: Martin Fox, MD

 

The KAMRA corneal inlay (Cornea- Gen) has become well-established for the safe restoration of near vision through its mechanism of small aperture optics. By expanding depth of focus, the inlay surgically enhances reading vision from intermediate to near range while preserving distance acuity in presbyopic patients.
When implanted in a deep femtosecond laser-created corneal pocket of the nondominant eye, the KAMRA inlay produces predictable outcomes with a high probability of patient acceptance and low rates of requested explantation (2% MLF). Our clinical results indicate that with careful patient selection and preparation, meticulous surgery, and postoperative care, KAMRA inlay surgery produces considerable results. Preoperatively, patients do best when refractive error is in the –0.75 D range with no levels of astigmatism. We have learned that those with refractive errors outside of this range need to be adjusted with laser vision correction (PRK or LASIK), performed simultaneously at the time of KAMRA inlay pocket implantation or prior to KAMRA inlay placement in a staged approach. Careful attention to tear film quality and levels of ocular light scatter as determined by the HD Analyzer (Visiometrics) will also ensure appropriate candidacy.
Success with the KAMRA inlay requires patience both from the physician and patient as the majority of KAMRA inlay recipients can take up to 3 months to fully appreciate the benefits of the small aperture optics and extended depth of focus delivered with this surgery. Poor neuroadaptation, which seems to occur more frequently in patients who display indeterminant ocular dominance, is the most common cause of patient discontent. Testing for monovision with contact lenses is helpful in determining which eye should receive the KAMRA inlay. In many instances, patients can also benefit from neuroadaptive exercises.
As with all forms of refractive surgery, maintenance of an excellent ocular surface is of utmost importance, but this is especially true for KAMRA inlay patients. The KAMRA inlay requires a robust tear film in order to work well, and therefore, punctal occlusion and topical lubricants are required along with Restasis (cyclosporine, Allergan) or Xiidra (lifitegrast, Shire) as adjunct topical therapeutics. Frustrated KAMRA inlay patients should be offered explantation, which could restore preoperative best corrected visual acuity.
Addressing the complaints of pseudophakic patients who are unhappy with their multifocal implant results can be daunting for the surgeon after uncomplicated cataract surgery. Once potential ocular surface and capsule clarity issues are addressed as contributing factors, the surgeon may consider the option of performing an intraocular lens exchange. This can be accomplished successfully in most situations, but it exposes the patient to the inherent risks associated with a secondary intraocular procedure. Patients receiving monofocal cataract implants wanting uncorrected reading vision can be equally problematic.
In the three cases presented here, multifocal implant patients with significant quality of vision issues at both distance and near were able to have their concerns addressed with a KAMRA corneal inlay. These cases highlight the potential of future applications for the KAMRA inlay, specifically as a therapeutic tool in the treatment of suboptimal vision quality in other clinical scenarios.
In the case of past cataract surgery with a monofocal implant, the KAMRA inlay with its mechanism of small aperture optics appears to be a good solution for the restoration of uncorrected reading acuity with improvement of uncorrected distance acuity.

About the doctors

Martin Fox, MD, FACS
Medical director
Cornea and Refractive Surgery Practice of New York
Surgical Consultant
Vision Group Holdings

Jeffrey Augustine, OD
Director of Clinical Operations
ClearChoice LASIK
Brecksville, Ohio

William Wiley, MD
Assistant clinical professor of ophthalmology
University Hospitals/Case Western University
Medical director
Cleveland Eye Clinic

Financial interests

Fox: CorneaGen
Augustine: AcuFocus, CorneaGen
Wiley: AcuFocus, CorneaGen

Contact information

Fox
: martinlfox@me.com
Augustine: draugustine@clearchoicelaser.com
Wiley: abrowning@clevelandeyeclinic.com

Case 1

69-year-old male with past history of LASIK complains of inadequate reading acuity and poor quality of vision in the distance following bilateral cataract surgery with implantation of Tecnis +2.75 multifocal IOL (model ZKB00,
Johnson & Johnson Vision)

Preoperative findings (10/17/17)
UCVA OD: 20/50+2 J7 c/o glare
UCVA OS: 20/50+2 J5 c/o glare

Ocular dominance: OS

MR OD: +1.25-0.50 x 90 20/30+2
Add: +2.50 J2
MR OS: +0.75-1.00 x 70 20/25-2
Add: +2.50 J2

AcuTarget HD OD: OSI 1.5 OSI mean 1.75
Central corneal thickness: 550 µm

Surgical planning (12/18/17)
Simultaneous PRK and KAMRA
implantation – OD
Treatment: +2.00 D PRK with mitomycin-C and amniotic membrane
Femtosecond laser pocket depth: 270 µm

Postoperative findings
4/03/18 UCVA OD: 20/50 J1+
9/05/18 UCVA OD: 20/30-2 J1+

HD OD (9/5/18): OSI 2.5, OSI mean 2.90
Patient comments: Delighted with reading acuity and reduction of visual halos

Case 2

71-year-old male with past history of bilateral cataract surgery with Tecnis +2.75 multifocal IOL (model ZKB00) (6/12); S/P YAG capsulotomy; patient complains of worsening quality of vision characterized by glare from bright light sources affecting both distance and near acuity and problematic vision while driving

Preoperative findings (6/20/17)
UCVA OD: 20/20-1 J1+ glare testing 20/50
UCVA OS: 20/20-1 J1+ glare testing 20/50

MR OD: –0.75-0.25 x 055 20/20-1
MR OS: –0.50-0.25 x 103 20/20-1

Ocular dominance: OD

HD OS: OSI 1.6 OSI mean 2.05
Central corneal thickness: 504 µm

Surgical planning (9/22/17)
Pocket KAMRA implantation – OS
Femtosecond laser pocket depth: 250 µm

Postoperative findings 8/10/18
UCVA OS: 20/30 J1+

Patient comments: Less visual fatigue; glare issue improved; happy with near vision

Case 3

64-year-old female 6 months post-cataract surgery with monofocal implants and nondominant OS targeted for –0.75 D outcome; patient was unhappy with visual quality and range of near acuity and wished to see better in the distance and be independent of reading glasses

Preoperative findings (9/16/18)
UCVA OD: 20/20 J7
UCVA OS: 20/40 J3 (difficult)

MR OD: +0.25-0.50 x 180 20/20
MR OS: –0.75-0.50 x 65 20/20

Ocular dominance: OD

HD OS: OSI 0.70 OSI mean 1.25
Central corneal thickness: 587 µm

Surgical planning (11/27/18)
Pocket KAMRA implantation
Femtosecond laser pocket depth: 280 µm

Postoperative findings
12/20/18 UCVA OS: 20/25+3 J1+

Patient comments: Patient delighted with improved acuity at both distance and near ranges

Successful use of the KAMRA corneal inlay after cataract surgery Successful use of the KAMRA corneal inlay after cataract surgery
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2019-05-06T14:23:38Z
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