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HomemiophthalmologyMacular Degeneration and Cataract Surgery

Macular Degeneration and Cataract Surgery

A trial being undertaken by Sydney eye surgery Personaleyes and two other eye surgeries around the world will assess the improvement in the quality of life achievable by implanting asymmetric refractive IOLs into the eyes of patients who have advanced macular degeneration.

The Macular Disease Foundation Australia estimates that over 1 million Australians above the age of 50 have macular degeneration. Approximately 162,000 Australians suffer vision loss from late stage AMD. Over the next 20 years this number is expected to double. In 2010 it was estimated that about 60,000 individuals were legally blind and about 20,000 people had vision between 6/24 and 6/60.1

In recent years anti-vegf treatment has greatly helped people with neovascular AMD. However, patients who are legally blind and those who have late dry AMD have not benefited from this. There is no treatment available that can restore the lost retina. A patient’s vision can only be improved with low vision aids, which project a magnified image of the object on to the normally functioning peripheral retina. While this retina may not have the resolving ability of the central macula, suitably enlarged images can be used to improve vision. Currently, all strategies to improve vision and quality of life are based upon this idea.

Low vision clinics offer a variety of solutions that comprise simple magnifiers, telescopes and electronic devices. These, in various combinations, can improve the quality of life for this group of individuals. However, there are limitations to what can be achieved. Simple hand held magnifiers and stand magnifiers are easy to use. As an individual’s need for magnification increases the focal length needs to be shortened resulting in a shorter working distance and smaller field of view. This often requires internal illumination, which then increases the weight and volume of the device. Patients often use two magnifiers – one simple magnifier for outdoors and one stand magnifier for indoor use. External telescopes offer greater magnification and can be purchased as isolated Galilean telescopes for fixed distance tasks such as watching TV or be incorporated in glasses as bioptics. However, again their field is often quite restricted (4-10deg) and often they are cosmetically unappealing for individuals.2 The successful use of all these devices depends on the dexterity of the individual and their motivation. As mentioned above, individuals often require multiple devices and the magnification is always inversely related to the field of view.

The successful use of all these devices depends on the dexterity of the individual and their motivation…

A number of attempts have been made to implant lenses in the eye close to the nodal point of the eye to provide both magnification and greater field of view. The aim was to lower the dependence on low vision aids. These intraocular lens based solutions often used the same principle as in a Galilean telescope, where a combination of a high plus objective lens and a high minus eyepiece lens create a magnified image. This principle was initially used in the teledioptric systems where a high minus lens was inserted into the capsular bag and high plus lens was placed in the spectacle plane. This solution did not gain widespread acceptance. The monocular high plus spectacle correction was cosmetically unappealing; there was

a significant amount of peripheral vision loss plus there was significant image blur with eye movement.3-6

Newer solutions implant both the high plus and high minus lenses inside the eye, rather than one in the eye and one in the spectacle. Currently, the Intraocular Lens for Visually Impaired People (IOL-VIP) and Intraocular Miniature Telescope (IMT) are available for people with advanced macular degeneration. The IOL-VIP involves implanting two lenses; typically a +53D biconvex anterior chamber IOL and a -63D biconcave IOL in the capsular bag. It provides x1.3 magnification for distance and a ‘prismatic effect’ due to lens misalignment. The latter feature is used to project the image towards the more intact peripheral retina. This lens system improves distance vision from 1.28 logMar to 0.77 logMar.7 It does not reduce peripheral vision and therefore may be implanted binocularly.

Unfortunately in most patients the improvement in best-corrected distance acuity is associated with a large hyperopic shift in subjective refraction of +8 to +9D. The ideal candidate for this procedure is a high myope, who with the hyperopic shift would achieve emmetropia and who has the space in the anterior chamber to accommodate the large IOL without losing endothelial cells. There have been cases where the space between the high plus IOL and the endothelium has been as little as 1.44mm (normal 3mm), which can increase the risk of angle closure glaucoma in normal and short eyes. Lastly, Orzalesi and colleagues claimed x6 magnification in reading vision and an increase in reading distance between 5.6cm to 12.6cm but others did not find a significant improvement in reading vision in patients with IOL-VIP system.7,8

Implantable Miniature Telescope

The Implantable Miniature Telescope (IMT) is the only lens currently in the market, which has received FDA approval.9 It is implanted in the worst eye of patients with macular degeneration and can achieve x2.2 or x3 magnification depending on the model inserted. This device is a complete telescope with wide-angle micro-optics that create a fixed-focus telephoto system. It is 4.4 mm long and when implanted in the capsular bag can protrude 0.1 to 0.5 mm anterior to the iris. Perhaps this protrusion explains the presence of inflammatory deposits in 50 per cent of eyes at two years.10 An 11mm limbal incision is needed to insert the lens and this along with the size of the lens results in a 25 per cent loss in endothelial cell density.10

Over a two year period 60 per cent of patients gained three lines or more.10 The difficulty with this technology has been the loss of binocularity. The better eye has to be used for navigation, while the worse eye is used for near vision tasks. The ocular dominance is not considered in the decision to insert an IMT. This results in significant anisekonia along with a constriction in visual field to 20deg, which limits fundus examination.11 Implantation of a telescope also prevents easy access to the posterior capsule in case of posterior capsular opacification. A pars plana capsulotomy was needed to remove posterior capsular opacification.12

Recently, a novel idea of implanting a multifocal iol with a myopic target of -2D has been used to improve magnification. Gayton and colleagues, report using a +4D Restor lens while targeting -2D target refraction to achieve the equivalent of +5.2D in the spectacle plane.13 This resulted in an improvement in near visual acuity in 90 per cent of cases along with an improvement in the quality of life. The only disadvantage was that while the corrected distance acuity improved in 70 per cent of cases, the uncorrected distance vision was reduced in 40 per cent, especially in patients who had binocular surgery.

The aims of all the strategies mentioned above were or are ambitious and required the loss of either binocularity or distance vision or subjective refraction. A solution that improves either distance or near vision without requiring a sacrifice of binocularity or distance or near vision would be more ideal. This is particularly important for this group of patients who have little vision to spare. Furthermore, all these improvements achieve a x1.3 to x3 magnification at significant surgical risk.

ARMD High Add IOL Trial

At Personaleyes, we are currently conducting a cataract surgery trial of an asymmetric refractive IOL (Lentis High Add lens, LS-313 MF80, Oculentis, Germany) with a +8 add, which will theoretically provide x2.4 magnification in the spectacle plane. Unlike the IOL-VIP and IMT solutions mentioned previously, this is a foldable single piece lens which can be inserted as part of a normal cataract operation through a small 2.2 mm clear corneal wound into the capsular bag with sutureless wound closure. This 11mm acrylic plate lens has a 6mm optic with two portions; a distance segment which occupies approximately 60 per cent of the optic and an asymmetric refractive near segment which occupies the remainder of the optic.

For an individual patient, the lens is ordered with the aim of achieving emmetropia with the distance portion. Therefore there is no reduction in navigation vision or reduction in field of view. The lens being close to the nodal point should allow for the x2.4 magnification with a considerably large field of view. This lens is designed to simultaneously project an image of a distance and near object on the retina. Theoretically there is a risk of causing dysphotopsias, however it is anticipated that the absence of macular function will prevent this group of patients from perceiving dysphotopsias.

We have successfully implanted this lens binocularly in an 81-year-old gentleman who lives independently. He had advanced macular degeneration in both eyes and cataracts in both eyes.

He was legally blind in both eyes with a best-corrected vision of 6/120(-3) (right eye) and 6/96 (+2) (left eye). Preoperatively, with a +4D add in the spectacle plane his near vision was N80 (right eye) and N64 (left eye) and binocularly N40. His fundus photos document his advanced macular degeneration.

The patient underwent bilateral sequential cataract surgery and had the Lentis High Add IOL (LS-313 MF80, Oculentis, Germany) was implanted in both eyes. His distance vision in the right eye improved slightly 6/120 (+3) and in the left eye improved to 6/48. He was able to read N36 (R) and N18 L at 25 cm. He has experienced a marked improvement in both his binocular distance and near vision. This promising result in an individual case suggests that this lens has the potential to improve the lives of people who have macular degeneration and cataracts (Figure 1).

Patient Recruitment Underway

Personaleyes is recruiting patients for both the control arm and the intervention arm of the ARMD high add IOL trial, which will be conducted in collaboration with the Low Vision Clinic at the Centre for Eye Health, University of New South Wales. Dr. Mei Boon and Ms. Sharon Obestein will provide preoperative and postoperative low vision assessments for the patients.

The control arm of the study is for patients who have had cataract surgery with a monofocal lens and have AMD without glaucoma. Participants will be asked to complete a patient questionnaire and an image of their macula will be taken.

The interventional arm is for patients who would have the cataract operation with the Lentis High Add IOL (LS-313 MF80, Oculentis, Germany). The inclusion criteria for the interventional arm of the study are:

  • Adults over the age of 50 who can consent for the procedure
  • Subjects with cataract

  • Subjects with age related macular degeneration

  • logMAR visual acuity between 1.3 (6/120)– 0.4 (6/15) preoperatively and postoperatively
  • IOL power between +15 D and +25 D

The success of the trial will be judged based on the improvement in the quality of life of the patient as measured by the validated Impact of Visual Impairment (IVI) questionnaire.14 The patients will also be assessed for a number of other parameters including distance vision, near vision, contrast sensitivity, field of view, reading speed and change in low vision requirements.

The statistical power calculation based on the IVI questionnaire will require 198 cases to confidently dismiss the null hypothesis of mild improvement in the quality of life. We, therefore, hope to recruit 198 patients for surgery and 198 patients in the control group. For more information visit: www.personaleyes.com.au/

Dr. Chandra Bala specialises in cataract, cornea and refractive surgery and glaucoma surgery and has comprehensive experience in the anterior segment of the eye. Dr. Bala has a number of research publications and is a senior clinical lecturer at Australian School of Advanced Medicine, Macquarie University. He is a VMO at Bankstown hospital; he operates at Macquarie University Hospital and performs refractive laser surgery at Personaleyes in Parramatta and at the York Street clinic in the City.

For more information about the trial contact Personaleyes: (AUS) 02 8833 7111 or

www.personaleyes.com.au/

References

1. Macular_Degeneration_Foundation_Deloitte_Access_Economics, Eyes on the future. 2011, Macular Degeneration Foundation: http://www.mdfoundation.com.au/LatestNews/MDFoundationDeloitteAccessEconomicsReport2011.pdf.

2. Nguyen, A., Nguyen A-T, Hemenger RP, Williams DR, Resolution, field of view and retinal illluminance of miniaturized bioptic telescopes and their clinical significance. J Vis Rehab, 1993. 7: p. 5-9.

3. Koziol JE, P.G., Cionni R, Chou JS, Portney V, Sun R, Trentacost D, Evaluation and implantation of a teledioptric lens sys- tem for cataract and age-related macular degeneration. Ophthalmic Surg, 1994. 25: p. 675-84.

4. Donn A, K.C., An ocular telephoto system designed to improve vision in macular disease. CLAO J, 1986. 12: p. 81-5.

5. Willis TR, P.V., Preliminary evaluation of the Koziol-Peyman teledioptric system for age-related macular degeneration. Eur J Im- plant Refract Surg 1989. 1: p. 271-6.

6. Peli, E., The Optical Functional Advantages of an Intraocular Low-Vision Telescope. Optometry and Vision Science, 2002. 79(4): p. 225-233.

7. Orzalesi, N., et al., The IOL-Vip System: a double intraocular lens implant for visual rehabilitation of patients with macular disease. Ophthalmology, 2007. 114(5): p. 860-5.

8. Luis Amselem, M.D.-L., Adelina Felipe, Jose M. Artigas, Amparo Navea, Salvador Garc ́ıa-Delpech, Clinical magnification and residual refraction after implantation of a double intraocular lens system in patients with macular degeneration. J Cataract Refract Surg, 2008. 34: p. 1571-1577.

9. Lane, S.S. and B.D. Kuppermann, The Implantable Miniature Telescope for macular degeneration. Current Opinion in Ophthalmology, 2006. 17(1): p. 94-8.

10. Hudson HL., S.R., Heier JS, Lane SS, Chang DF, Singerman LJ, Bradford CA, Leonard RE, IMT002 STUDY GROUP, Implantable Telescope for End-Stage Age-related Macular Degeneration: Long-term Visual Acuity and Safety Outcomes. American Journal of Ophthalmology, 2008. 146: p. 664-673.

11. Primo, S.A., Implantable miniature telescope: lessons learned. Optometry (St. Louis, Mo.), 2010. 81(2): p. 86-93.

12. Singer MA, D.C.M., Stelton CR, Boord T, Pars plana capsulotomy in a patient with a telescope prosthesis for age-related macular degeneration. Arch Ophthalmol. 2010;128., 2010. 128(8): p. 1065-7.

13. Gayton JL, M.R., Ernest PH, Seabolt RA, Dumont S,, Implantation of multifocal intraocular lenses using a magnification strategy in cataractous eyes with age-related macular degeneration. Journal of Cataract & Refractive Surgery, 2012. 38: p. 415-418.

14. Lamoureux, E.L., et al., Impact of cataract surgery on quality of life in patients with early age-related macular degeneration. Optometry & Vision Science, 2007. 84(8): p. 683-8.