Investigation of A New Dual-Optic Accommodating Intraocular Lens in

0 downloads 0 Views 2MB Size Report
design. Results: Twenty-one of 24 patients completed the study. At the end of one year, all had .... IOL explantation due to folded haptic: one patient. Severe ...
69th AIOC Proceedings, Ahmedabad 2011

This paper was conferred with the AIOS SANTE VISION AWARD for the BEST PAPER of ALL CATARACT Sessions. This paper was also judged the BEST PAPER of CATARACT-I Session. DR. MURTHY SOMASHEILA I: M.B.B.S. (1992), TN Medical College; M.S. (1996), LTM Medical College, Mumbai University; DOMS, FCPS, Mumbai; Cornea & Anterior Segment fellow (1998), LVPEI, Hyderabad; Uveitis & Ocular Pathology fellow (2000), Doheny Eye Institute, USA. Presently, Consultant, Cornea & Anterior Segment, Ocular Immunology & Uveitis Service, LVPEI, Hyderabad. E-mail: [email protected]

Investigation of A New Dual-Optic Accommodating Intraocular Lens in Cataract Surgery: Phase II Safety and Efficacy Study Dr. Murthy Somasheila I., Dr. Virender Sangwan S., Dr. Ashik Mohamed, Dr. Veerendranath Pesala Purpose: To evaluate the safety and efficacy of a dual-optic accommodating intraocular lens. Methods: Prospective interventional case series in which 24 eyes with uncomplicated senile cataract were enrolled to undergo phacoemulsification and placement of a new intraocular lens design. Results: Twenty-one of 24 patients completed the study. At the end of one year, all had best corrected distance visual acuity of 20/40 or better and 14 eyes (66.66%, 95% CI 43.11% to 84.52%) had uncorrected visual acuity of 20/40 or better. The mean minimum add required to reach 0.40 logMAR (N6/J2) or better was 1.75 D ± 0.58 one month, 1.78 ± 0.64 D at 3 months, and 2.08 ± 0.66 D at one year. Mean amplitude of accommodation at 3 D was 0.11 D, 0.24 D, and 0 D at one month, 3 months, and one year respectively. Conclusion: While the dual-optic IOL had uncorrected and best-corrected distance visual acuity and safety comparable standard monofocal lOL; there was no significant accommodation noted.

P

hacoemulsification and intraocular lens (IOL) implantation is now the standard of care in the management of cataract. Whilst this procedure results in excellent uncorrected distance visual acuity in most cases, patients will

Best Free Papers

continue to require supplementary intermediate and near visual correction. The development of IOLs that can produce an accommodative effect through normal ciliary muscle activity has been a goal of recent lens development. Investigation into novel polymers has been reported1, while silicone, widely used in other IOLs has been indicated as a suitable material in other preliminary studies.2 Existing marketed products are based on a single optic design that may move forward under ciliary muscle action to provide a pseudophakic accommodative response.3-6 A lens which utilizes two lens elements that can move relative to each other under the influence of ciliary body activity was designed and its results are reported here.

MATERIALS AND METHODS Prospective, single-center, non-comparative and non-randomized clinical investigation of the accommodating single-piece foldable silicone posterior chamber IOL to demonstrate feasibility and to monitor safety and effectiveness over 12 months. The study was approved by the Institutional Review Board.

Surgical Procedure

Standard phacoemulsification, peribulbar anesthesia, through a sclero-corneal incision. Post-operatively, all patients received Prednisolone acetate 1% six times a day, tapered over six weeks and Ciprofloxacin 0.3% eye drops four times a day for one week.

Patient Evaluation

The patient examination schedule comprised 7 visits (preoperative, operative, 1 and 7 days, 1, 3 and 12 months). Manifest subjective refraction at 3 meters for distance acuity and 40 cm for near acuity on log MAR visual acuity charts was done. Objective measurement of accommodation was done using the Shin-Nippon N Vision-K 5001 Auto refractor (Tokyo, Japan). Lens stability was assessed using the Oculus Pentacam (Washington, USA) initially, for the first 10 patients. Statistical analysis: The data was examined using descriptive statistics, analysis of variance and/or t-tests where appropriate.

RESULTS A total of 24 eyes of 24 patients: 15 male and 9 female with mean age 51.71 ± 8.56 years (range 34 to 70 years) were enrolled. Twenty-one (87.5%) completed one year follow-up.

Distance visual acuities All: 20/40 or better at the one year. Mean spherical equivalence by manifest subjective refraction was -0.13 ± 1.90 D. Twelve of the 21 eyes (57.14%, 95% CI 34.44% to 77.41%) were within ±0.50 D and 16 (76.19%, 95% CI 52.45% to 90.88%) were within ±1.00 D. Fourteen eyes (66.66%, 95% CI 43.11% to 84.52%) had an uncorrected distance visual acuity of 0.3 log MAR (20/40) or better. At one year

69th AIOC Proceedings, Ahmedabad 2011

follow-up, BCDVA was 0.3 log MAR (20/40) or better in all eyes. 14 eyes (66.66%, 95% CI 43.11% to 84.52%) had BCDVA of 20/20 at one year.

Near visual acuities All patients achieved stable best distance corrected near visual acuity (BDCNVA) during the follow-up. The mean was 0.39 ± 0.17 log MAR at one month, 0.43 ± 0.17 log MAR at 3 months, and 0.44 ± 0.14 log MAR at one year (P = 0.598, ANOVA). 70.83%, 56.52% and 66.66% of patients were able to read 0.5 log MAR (J3 or better) at one month, 3 months and one year postoperatively. The mean minimum add required to reach 0.40 log MAR (N6/J2) or better was 1.75 D ± 0.58 D at one month, 1.78 ± 0.64 D at 3 months, and 2.08 ± 0.66 D at one year.

Intermediate The mean best distance corrected intermediate visual acuity (BDCIVA) was also stable during the follow-up. It was 0.25 ± 0.17 log MAR at one month, 0.27 ± 0.18 log MAR at 3 months, and 0.32 ± 0.19 log MAR at one year (P = 0.390, ANOVA). The mean amplitude of accommodation at 3 D evaluated using the auto refractor was 0.11 D, 0.24 D, and 0 D at one month, 3 months, and one year respectively.

Complications and adverse events IOL explantation due to folded haptic: one patient. Severe inflammation (3+ vitreous haze) one patient, mild inflammation: 2 eyes.

DISCUSSION The lens appeared to provide only a minimal amount of accommodative capacity, which may be seen even with a mono focal lens. The uncorrected near visual acuity, with distance correction in place showed an accommodative range of about 0.75 to 1 D at one year, therefore these patients would require less near add (2.08 ± 0.66 D at one year). However, this accommodation can be explained by non-accommodative methods including pseudo-accommodation and increased depth of focus due to the dual-optic design. The results also show that the mean amplitude of accommodation at 3 D was 0.11 D, 0.24 D, and 0 D at one month, 3 months, and one year respectively, once again demonstrating no accommodation. Ultrasound biomicroscopy was also used to study the change in the separation between the two optics from the paralyzed to the accommodative state of the ciliary muscle. However, no significant difference was noted. Ossma et al7 reported their results of a similar design dual-optic accommodative IOL and showed a mean accommodation range of 3.22 D in their group. Their patients achieved a substantial improvement in uncorrected near visual acuity at every follow-up visit. This observation is surprising, given that the capsular bag would gradually undergo increased contracture and lead to more restrictive forces against movement of the IOL, leading to decrease in accommodation with time. In the present study, the near visual acuities were stable with a trend

Best Free Papers

towards decreased accommodation noted over the follow-up (did not achieve significance). Another deficiency in the study by Ossma et al was their high lost to follow-up. The authors had concluded that the dual-optic IOL is an option to provide accommodative function in pseudophakic patients. The reasons for failure of this lens design can be attributed to the inability of the design to balance the spring forces of the haptic and the compressive forces of the capsular bag on the pressure on the IOL. The IOL haptic need to be pliable enough in order to get compressed by the forces of the ciliary muscle and on the other hand, the haptics should be rigid enough not to get distorted or folded by the capsular bag. The failure of movement of the two optics from each other as demonstrated by ultrasound biomocroscopy, suggests that the haptics were trapped into place by the capsular bag and therefore there was no spring movement taking place at all. Unlike the results obtained by Ossma et al, in which the authors were planning future trials with larger cohort of patients, our study suggests that this IOL design is not adequate and further research is now required to modify this IOL in the laboratory, before we can commence with large cohort of patients. While the dual-optic IOL had uncorrected and best-corrected distance visual acuity and safety comparable to standard mono focal IOL; there was no significant accommodation provided by this IOL.

REFERENCES 1.

De Groot JH, Spaans CJ, van Calck RV, van Beijma FJ, Norrby S, Pennings AJ. Hydrogels for an accommodating intraocular lens. An explorative study. Biomacromolecules 2003;4:608-16.

2. McLeod SD, Portney V, Ting A. A dual optic accommodating foldable intraocular lens. Br J Ophthalmol 2003;87:1083-5. 3.

Kuchle M, Nguyen NX, Langenbucher A, Gusek-Schneider GC, Seitz B, Hanna KD. Implantation of a new accommodative posterior chamber intraocular lens. J Refract Surg. 2002;18:208-16.

4.

Langenbucher A, Huber S, Nguyen NX, Seitz B, Kuchle M. Cardinal points and image-object magnification with an accommodative lens implant (1 CU). Ophthalmic Physiol Opt. 2003;23:61-70.

5.

Langenbucher A, Seitz B, Huber S, Nguyen NX, Kuchle M. Theoretical and measured pseudophakic accommodation after implantation of a new accommodative posterior chamber intraocular lens. Arch Ophthalmol. 2003;121:1722-7.

6.

Cumming JS, Slade SG, Chayet A. Clinical evaluation of the model AT-45 silicone accommodating intraocular lens: results of feasibility and the initial phase of a Food and Drug Administration clinical trial. Ophthalmology 2001;108:2005-9; discussion 2010.

7.

Ossama Il, Galvis A, Vargas LG, Trager MJ, Vagefi MR, McLeod SD. Synchrony dual optic accommodating intraocular lens. Part 2: Pilot clinical evaluation. J Cataract Refract Surg. 2007;33:47-52.