Visual outcome after trifocal IOL implant in a patient with cornea guttata. A case report.

Background We report the case and management of a patient that started with primary cornea guttata symptoms after cataract surgery with trifocal intraocular lens (IOL) implant. The unusual postoperative presentation of the disease in association with a trifocal IOL resulted in increased corneal surface aberrations that resulted in visual dissatisfaction. Case presentation A 67 year-old male was evaluated due to blurred vision for two months, as well as a desire to stop using glasses in his everyday life. At the initial refraction, myopia, corneal astigmatism and nuclear cataract were diagnosed in both eyes. A nuclear cataract was diagnosed in both eyes. Phacoemulsication surgery was performed in OS, implanting a trifocal IOL. The postoperative refraction in OS was -1.25DCx120º, with a best-corrected visual acuity (BCVA) of 20/20. Six months later, the patient kept complaining of blurred vision and night glare. In slit lamp examination, corneal guttae were denoted and changes in corneal endothelium morphology suggested primary cornea guttata. A monofocal IOL exchange was performed in order to reduce corneal aberrations with excellent outcome at 2-year follow up. Conclusions Screening for endothelial dysfunction is a key element for successful outcomes in cataract surgery. Corneal guttae accent optical aberrations when in combination with premium IOLs.


Background
Corneal guttae are focal excrescences of extracellular matrix in Descemet's membrane. They initially appear on specular re ection as scattered and isolated dark structures. 1 Specular microscopy con rms the clinical ndings. 2 Because symptoms start around the fth decade of life, a signi cant number of patients with cornea guttata could have cataracts as well. Likewise, symptoms caused by guttae are similar to those caused by cataracts (glare, loss of contrast sensitivity, blurred vision). 3 The age overlap between this two conditions poses a challenge for the ophthalmologist in the surgical decision making, as endothelial cell damage during surgery may accelerate endothelial cell loss between 4-25%. 3

Case Presentation
A 67 year-old male, of Jewish descent, came for an ophthalmological evaluation after a two-month history of blurry vision, as well as a desire to stop using eyeglasses in his everyday life. He does not refer any other relevant medical history.
At his initial assessment, uncorrected distance visual acuity (UDVA) was 20/20 in OD and 20/30 in OS.
Uncorrected near visual acuity was J3. The initial refraction was -0.50DCx120º in OD and -1.75DS/-1.50DCx70º in OS. Corrected distance visual acuity (CDVA) was 20/20 for both eyes. Nuclear cataracts were observed in both eyes during slit lamp examination. The other anterior segment structures and fundus examination were unremarkable. The assessment for a surgical solution was initiated.
A corneal topography using the OPD Scan-III (Nidek Co., LTD. Gamagori, Japan) was performed in OS.
SimK was 42.22@135º/ 41.45@45º. For IOL power calculation, an optical biometry using IOLMaster 500 (Carl Zeiss, Oberkochen, Germany) together with Barrett Universal II formula was used. The average calculation of lens power was +17.00D for OS.
After assessment, phacoemulsi cation surgery and IOL placement were done in OS, implanting a trifocal lens model AT LISA tri 839MP (Carl Zeiss, Oberkochen, Germany). The surgery was performed uneventfully.
During the rst week of the postoperative period, the UDVA was 20/20 in OS. The refraction at this time was -1.25DCx120º.
Six months into the postoperative period, the patient noted persistent blurred vision and night glare appeared. Slit lamp examination was performed and cornea guttata was observed. A specular microscopy (Fig 1) with EM-3000 (Tomey, Phoenix, AZ, USA) and a corneal topography using OPD Scan-III were performed. As visual symptoms didn't improve over time, or with the spherocylindrical correction of residual error, a surgical option was preferred, and an IOL exchange was proposed. A second low-frequency optic interferometry with IOL Master 500 was performed, and using Barrett Universal II Formula, an average lens power of +18.00D was calculated. A monofocal aspheric IOL, the ZCB00 (Abbott Medical Optics Inc, Santa Ana, CA, USA), was favored.
During the rst week after the IOL exchange, UDVA was 20/25. Refraction at this time was -0.50Ds/-0.50DCx 90º in OS. Postoperative period developed without complications.
Patient follow-up was given for two years. His last UDVA was 20/20 in both eyes and near visual acuity was J1. His last specular microscopy showed a CCT of 593, CD of 1332 cells/mm2, polymegathism of 64% and pleomorphism of 33% in OD; and a CCT of 546, CD of 1105 cells/mm2, polymegathism of 68% and pleomorphism of 26% in OS.

Page 4/7
The growing requirements of adults over 65 years old and the increasing popularity of premium IOLs, warrant a meticulous preoperative screening. Although cataract surgery outcomes and complications have remained stable for the last decade, preoperative ophthalmological evaluation has not been standardized. 4,5 IOL options must be carefully explored when corneal guttae are present. Wacker et al. 6 found that anterior corneal HOAs were increased in moderate and advanced Fuchs´ endothelial dystrophy (FED), compared with controls, before clinically visible corneal edema. Likewise, posterior corneal HOAs and corneal backscatter were increased even in mild FED, suggesting that surface aberrations may occur earlier than previously thought. Corneal guttae reduce contrast sensitivity and by implanting premium IOL, a second source of optical degradation is added. 7,8 Corneal surface aberrations, in combination with premium IOLs, can result in high visual dissatisfaction. Photopic phenomena (38.2%) and blurred vision (36.8%) are the most common presenting symptoms. 9 A study by Watanabe et al. 8 concluded that straylight from corneal guttae may be the main cause of optical degradation. Quanti cation of corneal guttae may offer a method for objectively evaluating quality of vision in patients with FED, even those who have cataract.
In order to improve our patient's visual quality, IOL options were explored. Monofocal IOL exchange was the optimum choice in our patient. Tecnis ZCB00 was selected for its association with reduced chromatic aberration. Tecnis IOLs made of the acrylic Sensar material were not associated with glistenings except for only one in-vitro study that found minimal non-signi cant glistenings. 10 Conclusions Screening for endothelial dysfunction is a key element for successful outcomes in cataract surgery. We recommend screening for endothelial pathology in all patients who are candidates to cataract surgery, especially when considering premium IOLs, as this kind of IOL may magnify HOAs and could add a second layer of optical degradation in patients with corneal guttae.
An IOL exchange alone was proposed as a nal surgical solution. Slow progress and improvement of visual quality was observed in the follow-up at 2 years.

Declarations
Ethics approval and consent to participate *This study was approved by the Ethics Committee of the Tecnologico de Monterrey School of Medicine (Monterrey, Mexico) and followed the tenets of the Declaration of Helsinki and its later amendments. Informed consent was obtained for the participating subject.

Supplementary Files
This is a list of supplementary les associated with this preprint. Click to download. supplement1.pdf