Posterior Segment Visualization in Eyes With Small ... · eyes were pseudophakic with a monofocal...

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538 REPORT M odern cataract surgery allows surgeons to customize and tailor the refractive outcome to the visual needs of individual patients and this has led to increased patient expectation for spectacle independence following cataract surgery. 1 Presbyopia-correcting intraocular lenses (IOLs) have been shown to provide good unaided vision at dis- tance, intermediate, and near vision when implanted binocularly. 2-4 However, due to issues such as glare, halos, and decreased contrast associated with diffrac- tive optics, other options including presbyopic laser in situ keratomileusis and corneal inlays are available for treating presbyopia. 5,6 The small-aperture corneal inlay (KAMRA; Acufocus, Inc., Irvine, CA) employs the principle of small-aperture optics and has been shown to improve unaided intermediate and near vi- sion with minimum to no effect on distance vision when implanted monocularly. 6 Recently, the same principle of small-aperture optics has been applied at the lenticular plane to develop a new small-aperture IOL. The IC-8 (Acufocus, Inc.) is a single-piece, hydro- phobic acrylic, monofocal, small-aperture IOL with a ABSTRACT PURPOSE: To evaluate the posterior segment visualization in patients with small-aperture intraocular lens (IOL) implantation. METHODS: In this prospective, comparative case series, 15 pa- tients who had unilateral implantation of the small-aperture IOL in their non-dominant eyes were recruited. Their fellow eyes were pseudophakic with a monofocal IOL in 14 patients and phakic in 1 patient. All underwent bilateral posterior seg- ment clinical investigations including fundus photography, threshold perimetry, and optical coherence tomography of the posterior pole including optic nerve head. The results from these investigations were graded by a clinician masked to the laterality and type of IOL. Patient 11 developed postoperative endophthalmitis 4 weeks following cataract surgery with im- plantation of a small-aperture IOL and underwent pars plana vitrectomy. The intraoperative view of the posterior segment was subjectively evaluated by the retinal surgeon. RESULTS: All 15 patients had successful image captures with all clinical investigative tools with no differences in im- age quality detected between the images obtained from the monofocal pseudophakic and small-aperture IOL eyes. The small-aperture IOL did not subjectively obstruct the intraoper- ative view for the retinal surgeon during pars plana vitrectomy. CONCLUSIONS: Standard posterior segment investigations including non-mydriatic fundus photography, optical coher- ence tomography, and automated perimetry can be safely and effectively performed in eyes with small-aperture IOLs. There is no difference in the image quality. [J Refract Surg. 2019;35(8):538-542.] From the Department of Ophthalmology, University Hospital Ayr, Ayr, Scotland, United Kingdom (SS, LWK, ZK); and the School of Health and Life Sciences, University of West of Scotland, Ayr, Scotland, United Kingdom (SS, LWK). Submitted: March 16, 2019; Accepted: July 9, 2019 Mr. Srinivasan is a member of the medical advisory board of Acufocus, Inc. The remaining authors have no financial or proprietary interest in the materials presented herein. © 2019 Srinivasan, Khoo, & Koshy; licensee SLACK Incorporated. This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0). This license allows users to copy and distribute, to remix, transform, and build upon the article, for any purpose, even commercially, provided the author is attributed and is not represented as endors- ing the use made of the work. Correspondence: Sathish Srinivasan, FRCSEd, FRCOphth, FACS, Department of Ophthalmology, 3rd Floor, University Hospital Ayr, Dalmellington Road, KA6 6DX, Ayr, Scotland, United Kingdom. E-mail: [email protected] doi:10.3928/1081597X-20190710-01 Posterior Segment Visualization in Eyes With Small-Aperture Intraocular Lens Sathish Srinivasan, FRCSEd, FRCOphth, FACS; Lin Wei Khoo, MBChB; Zachariah Koshy, DNB, FRCS(G)

Transcript of Posterior Segment Visualization in Eyes With Small ... · eyes were pseudophakic with a monofocal...

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R E P O R T

Modern cataract surgery allows surgeons to customize and tailor the refractive outcome to the visual needs of individual patients

and this has led to increased patient expectation for spectacle independence following cataract surgery.1 Presbyopia-correcting intraocular lenses (IOLs) have been shown to provide good unaided vision at dis-tance, intermediate, and near vision when implanted binocularly.2-4 However, due to issues such as glare, halos, and decreased contrast associated with diffrac-tive optics, other options including presbyopic laser

in situ keratomileusis and corneal inlays are available for treating presbyopia.5,6 The small-aperture corneal inlay (KAMRA; Acufocus, Inc., Irvine, CA) employs the principle of small-aperture optics and has been shown to improve unaided intermediate and near vi-sion with minimum to no effect on distance vision when implanted monocularly.6 Recently, the same principle of small-aperture optics has been applied at the lenticular plane to develop a new small-aperture IOL. The IC-8 (Acufocus, Inc.) is a single-piece, hydro-phobic acrylic, monofocal, small-aperture IOL with a

ABSTRACT

PURPOSE: To evaluate the posterior segment visualization in patients with small-aperture intraocular lens (IOL) implantation.

METHODS: In this prospective, comparative case series, 15 pa-tients who had unilateral implantation of the small-aperture IOL in their non-dominant eyes were recruited. Their fellow eyes were pseudophakic with a monofocal IOL in 14 patients and phakic in 1 patient. All underwent bilateral posterior seg-ment clinical investigations including fundus photography, threshold perimetry, and optical coherence tomography of the posterior pole including optic nerve head. The results from these investigations were graded by a clinician masked to the laterality and type of IOL. Patient 11 developed postoperative endophthalmitis 4 weeks following cataract surgery with im-plantation of a small-aperture IOL and underwent pars plana

vitrectomy. The intraoperative view of the posterior segment was subjectively evaluated by the retinal surgeon.

RESULTS: All 15 patients had successful image captures with all clinical investigative tools with no differences in im-age quality detected between the images obtained from the monofocal pseudophakic and small-aperture IOL eyes. The small-aperture IOL did not subjectively obstruct the intraoper-ative view for the retinal surgeon during pars plana vitrectomy.

CONCLUSIONS: Standard posterior segment investigations including non-mydriatic fundus photography, optical coher-ence tomography, and automated perimetry can be safely and effectively performed in eyes with small-aperture IOLs. There is no difference in the image quality.

[J Refract Surg. 2019;35(8):538-542.]

From the Department of Ophthalmology, University Hospital Ayr, Ayr, Scotland, United Kingdom (SS, LWK, ZK); and the School of Health and Life Sciences, University of West of Scotland, Ayr, Scotland, United Kingdom (SS, LWK).

Submitted: March 16, 2019; Accepted: July 9, 2019

Mr. Srinivasan is a member of the medical advisory board of Acufocus, Inc. The remaining authors have no financial or proprietary interest in the materials presented herein.

© 2019 Srinivasan, Khoo, & Koshy; licensee SLACK Incorporated. This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0). This license allows users to copy and distribute, to remix, transform, and build upon the article, for any purpose, even commercially, provided the author is attributed and is not represented as endors-ing the use made of the work.

Correspondence: Sathish Srinivasan, FRCSEd, FRCOphth, FACS, Department of Ophthalmology, 3rd Floor, University Hospital Ayr, Dalmellington Road, KA6 6DX, Ayr, Scotland, United Kingdom. E-mail: [email protected]

doi:10.3928/1081597X-20190710-01

Posterior Segment Visualization in Eyes With Small-Aperture Intraocular LensSathish Srinivasan, FRCSEd, FRCOphth, FACS; Lin Wei Khoo, MBChB; Zachariah Koshy, DNB, FRCS(G)

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diameter of 12.5 mm, 6-mm optics, and “C” loop hap-tics (Figure 1). Embedded within the optic is a mask made of polyvinylidene fluoride and nanoparticles of carbon with an overall diameter of 3.23 mm and a cen-tral aperture of 1.36 mm. This IOL is implanted mon-ocularly in the non-dominant eye for the correction of presbyopia and has been shown to provide a continu-ous range of good unaided distance, intermediate, and near vision.7,8

The purpose of this study was to evaluate posterior segment visualization in eyes that had undergone IC-8 IOL implantation.

PATIENTS AND METHODSIn this prospective fellow eye comparative study,

15 eyes of 15 patients were included. All had bilateral cataracts except for one (patient 10) who had a unilat-eral cataract. All except one underwent clear corneal phacoemulsification with implantation of the small-aperture IOL in the non-dominant eye and a colorless monofocal IOL (409 MP; Carl Zeiss Meditec AG, Jena, Germany) in the fellow eye. The patient with unilateral cataract underwent phacoemulsification with implan-tation of the small-aperture IOL. There was no other ocular morbidity in the study group. Two months fol-lowing cataract surgery, a trained ophthalmic staff nurse performed the following standard posterior seg-ment examinations bilaterally in all patients: fundus photography with a non-mydriatic fundus camera (Canon CR-2 Plus; Canon, Tokyo, Japan), 24-2 thresh-old automated perimetry (Humphrey Field Analyzer 3, automated visual field analyzer; Carl Zeiss Meditec AG), and optical coherence tomography (OCT) of the

posterior pole and optic nerve head with two com-mercially available devices (Cirrus 5000; Carl Zeiss Meditec AG, and Spectralis; Heidelberg Engineering, Heidelberg, Germany). All investigations were per-formed in scotopic conditions without topical myd-riatic agents. An independent ophthalmologist (ZK) who was masked to the laterality and type of IOL used then evaluated and scored the digital images of the above-mentioned investigations based on a scoring scale (Table 1).

Surgical TechniqueCataract surgery was performed by a single surgeon

(SS) under topical and intracameral anesthesia. Fol-lowing 1.8-mm clear corneal phacoemulsification, a colorless, single-piece, preloaded, hydrophilic plate

Figure 1. High-magnification photograph of the IC-8 small-aperture intraocular lens (Acufocus, Inc., Irvine, CA) with the central mask.

TABLE 1Grading Scale Used by the Masked Observer to Grade the Quality of the Images

GradeNon-mydriatic Fundus

Photography 24-2 Automated Perimetry OCT of the Macula OCT of the ONH4 Very clear of the posterior

poleVery clear view of the entire visual field, with no field defects

Very clear view, all layers of retina and foveal pit visible

Very clear view, all margins of the ONH and all four quad-rants of the NFL visible

3 Mild peripheral shadowing with glare

Mild, peripheral artifacts, causing ring scotomas

Mild obstruction and shad-owing but retinal layers and foveal pit visible

Mild, peripheral artifacts, ONH visible but NFL view obstructed

2 Moderate shadowing, obscur-ing the details of the retinal vessel

Moderate paracentral ring scotomas

Moderate obstruction and shadowing, retinal layers not visible but foveal pit visible

Moderate obstruction and shadowing, no NFL visibility but ONH visible

1 Severe shadowing, obscuring view of the macula and optic disc

Severe ring scotomas with no view of the physiological blind spot

Severe paracentral defects, with no clear view of the reti-nal layers or foveal pit

Severe obstruction, ONH just visible

0 No clear view, unable to make out any details

Central “black out” with no normal field plot

No clear view, unable to make out any details

No clear view, unable to make out any details

OCT = optical coherence tomography; ONH = optic nerve head; NFL = nerve fiber layer

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haptic IOL (409 MP; Carl Zeiss Meditec AG) was in-jected into the capsular bag through a 1.8-mm clear corneal wound in the dominant eye of the patient. For the non-dominant eye, following 1.8-mm clear corne-al phacoemulsification, the wound was enlarged to 3 mm to facilitate insertion of the small-aperture IC-8 IOL in the capsular bag. A digital caliper (CALLISTO Eye; Carl Zeiss Meditec AG) set at 5.5 mm and cen-tered on the patient-fixated coaxially sighted corneal light reflex from the operating microscope (Lumera 700; Carl Zeiss Meditec AG) was used to center the capsulorhexis. The IC-8 IOL was centered in the cap-sular bag over this reflex with a slight nasal bias. There were no intraoperative complications. At the end of the procedure, all eyes received intracameral admin-istration of 0.1 mL of preservative-free cefuroxime (Aprokam; Thea Pharmaceuticals, Clermont-Ferrand, France) and postoperatively all were treated with topi-cal corticosteroid (Pred forte 1%; Allergan, Irvine, CA) for 4 weeks.

RESULTSThe trained ophthalmic nurse was able to perform

non-mydriatic fundus photography (Figure 2), 24-2 automated threshold perimetry (Figure 3), and OCT scan of the macula and the optic nerve head using two

commercially available OCT machines. There were no cases of image capture failure in the small-aperture IOL eye with any of the investigative tools. The masked observer (an experienced retinal surgeon) could not detect any difference in the image quality between the standard monofocal IOL and the small-aperture IOL eye and marked a score of grade 4 (ie, clear view, able to clearly view and interpret the test results) bilaterally for all posterior segment investigative tools. Moreover, patient 11, who underwent unilateral implantation of the IC-8 IOL, developed postoperative endophthalmi-tis 4 weeks following an uncomplicated cataract sur-gery. Vitreous biopsy showed no organisms on Gram stain and culture. Six weeks following the intravitreal antibiotic injection, he underwent pars plana vitrec-tomy for severe vitreous opacities. A non-contact fun-dus viewing system (RESIGHT 500; Carl Zeiss Meditec AG) was used during vitrectomy. Intraoperatively, the retinal surgeon (ZK) was able to visualize the posterior pole and the peripheral retina through the IC-8 IOL and was able to perform all maneuvers, including a thorough and complete posterior vitrectomy, inducing a complete posterior vitreous detachment, shaving the vitreous base, and examining the peripheral retina for any entry site tears. Subjectively, the retinal surgeon believed that the IC-8 small-aperture IOL did not com-

Figure 2. Fundus photographs cap-tured with a non-mydriatic fundus camera. (A) Phakic eye showing paracentral light scatter from the natural lens (blue arrow). (B) Eye with IC-8 small-aperture intraocular lens (IOL) (Acufocus, Inc., Irvine, CA) showing a crisper paracentral image due to the small-aperture IOL block-ing the stray light with no compro-mise of the posterior pole view. (C) Anterior segment view through the fundus camera showing the small-aperture IOL. (D) Side profile view of the non-mydriatic fundus camera.

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promise his intraoperative view. The entire technique is shown in Video 1 (available in the online version of this article).

DISCUSSIONThe impact of loss of accommodation on the qual-

ity of life has placed presbyopia treatment in the fore-front of clinical research.9 The surgical options for the treatment of presbyopia can be broadly classified as treatments at the corneal plane with either presbyopic laser treatment creating a multifocal corneal profile or corneal inlays and interventions at the lenticular plane with lens-based surgery combined with implan-tation of multifocal, trifocal, or extended depth of fo-cus IOLs.

Diffractive and refractive multifocal/trifocal lenses work by splitting the incident light, thereby inducing light scatter.10 This forward scattered light from a glare source forms a veil of luminance over the retina. This results in disc halos on the retina because the out-of-focus image has a greater diameter than the sharp im-age on the retina.11 The unwanted effect of light on the out-of-focus image may be visually disturbing, espe-cially when the relative energy distribution between the distance and near images is altered following pu-

pil dilation.12 There are reports highlighting the issues encountered by retinal surgeons when performing vitrectomy in eyes with multifocal IOLs, which range from loss of intraoperative focus to constant need of readjustment of intraoperative focus, decreased intra-operative contrast/ghost images, and problems during fluid–air exchange.13,14

The IC-8 small-aperture IOL received Conformité Européenne (CE) approval in 2015. It works on the same principle as the KAMRA corneal inlay based on small-aperture optics. Previous reports where sur-geons have undertaken cataract surgery15 and pars plana vitrectomy16 in eyes with the KAMRA corneal inlay have reported no issues in relation to the intra-operative view. The diameter of the mask on the IC-8 IOL is 15% smaller than that of the KAMRA corneal inlay (overall diameter: 3.23 mm, central aperture: 1.36 mm compared to the KAMRA corneal inlay with an overall diameter: 3.8 mm, central aperture: 1.6 mm) and is flat with no curvature compared to the KAMRA corneal inlay, which has a curvature of 7.5 mm.7 There has been no previous report evaluating the posterior segment view both clinically and intraoperatively with the small-aperture IC-8 IOL. In this prospective, observer-masked comparative case series, we were

Figure 3. (A) Automated perimetry from the pseudophakic right eye with a monofocal intraocular lens (IOL). (B) Automated perimetry from the pseudophakic left eye with a small-aperture IOL.

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able to demonstrate that the small-aperture IOL does not seem to interfere with any of the clinical tools used for posterior segment investigations. Moreover, intraoperatively, the retinal surgeon was able to per-form all standard vitrectomy steps including inducing a posterior vitreous detachment, performing complete vitrectomy with shaving of the vitreous base, and ex-amining the peripheral retina by indentation to check for entry site tears. However, we appreciate that this does not demonstrate how the intraoperative view would be affected in other vitreoretinal procedures such as membrane peeling. The physiological magnifi-cation induced by the human cornea17 combined with the use of an indirect viewing system for vitrectomy provides a good magnified view through the central aperture of the IOL to visualize the posterior pole. There was no distortion or ghosting of the intraopera-tive view as previously reported with refractive and diffractive IOLs.

This initial case series demonstrates that standard posterior segment examination can be safely and effec-tively performed through a small-aperture IOL. This study is limited by the lack of data examining the pe-ripheral retina with or without scleral indentation in eyes with small-aperture IOL implantation.

AUTHOR CONTRIBUTIONSStudy concept and design (SS); data collection (SS,

ZK); analysis and interpretation of data (SS, LWK); writing the manuscript (SS, LWK); critical revision of the manuscript (SS, LWK, ZK)

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