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Erdinest N, London N, Landau D, Barbara R, Barbara A, Naroo SA. Higher order aberrations in keratoconus. Int Ophthalmol 2024; 44:172. [PMID: 38594548 DOI: 10.1007/s10792-024-03118-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 03/24/2024] [Indexed: 04/11/2024]
Abstract
INTRODUCTION Keratoconus is a progressive disorder of the cornea that causes thinning (Sedaghat et al. in Sci Rep 11(1):11971, 2021), ectasia, and irregular astigmatism, resulting in poor visual acuity that cannot be corrected with standard sphero-cylindrical spectacle lenses. One feature distinguishing keratoconic corneas is ocular aberrations, manifesting up to five or six times the amount of higher-order aberrations than a normal, healthy eye. These aberrations can cause visual disturbances even at the very early stages of the disease. METHODS In the past, a diagnosis was derived from clinical symptoms, but technological advances have revealed multiple pre-clinical features, allowing for the differentiation between keratoconic and normal eyes at a much earlier stage. These include anterior and posterior corneal surface elevations, the corneal pachymetry profile, corneal epithelial patterns, wavefront aberration metrics, and corneal biomechanics (Sedaghat et al. in Sci Rep 11(1):11971, 2021).This review discusses the aberrations associated with keratoconus, how to measure them, and treatment methods to minimize their negative influence. CONCLUSIONS Early diagnosis can lead to early treatment and may allow for arresting progression, thereby improving the long-term prognosis. With the acceleration of refractive surgery, it is important to identify patients with keratoconus, as they are usually contraindicated for refractive surgery.
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Affiliation(s)
- Nir Erdinest
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | | | - David Landau
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ramez Barbara
- Ophthalmology Department, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Adel Barbara
- IVISION Cornea and Refractive Surgery Center, Haifa, Israel
| | - Shehzad A Naroo
- College of Health and Life Sciences, Aston University, Birmingham, UK
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Krolo I, Bećirević AK, Radman I, Sabol I, Ravlić MM, Ratković M, Belovari M. Impact of soft and rigid gas-permeable contact lenses on visual performance in mesopic conditions. Indian J Ophthalmol 2024; 72:S229-S232. [PMID: 38099579 DOI: 10.4103/ijo.ijo_628_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 08/11/2023] [Indexed: 12/19/2023] Open
Abstract
CONTEXT Evaluation of visual quality in soft and rigid gas-permeable contact lens wearers, with an emphasis on twilight vision. PURPOSE To assess the visual acuity and visual performance at dusk before and after soft and rigid gas-permeable contact lens (CL) correction in healthy subjects. SETTINGS AND DESIGN This prospective study was conducted in a tertiary eye-care center. METHODS Sixty eyes corrected with soft contact lenses (SCLs) and 30 eyes with rigid gas-permeable contact lenses (RGPCLs) were enrolled in this study. Patients underwent corrected distance visual acuity with spectacles (CDVAs), corrected distance visual acuity with contact lenses (CDVAcl), and twilight vision (TV) testing (Vista Vision Far-Pola, DMD MedTech charts). Parameters were evaluated before and after the CL fitting and repeated 3 months after the baseline visit. STATISTICAL ANALYSIS USED MedCalc for Windows, version 11.4 (MedCalc Software, Ostend, Belgium). RESULTS Rigid gas-permeable CL wear showed significant improvement in CDVAcl compared to wearing spectacles on both visits ( P = 0.0039 and P = 0.0003, respectively). TV with CLs was significantly better in both groups compared to the TV with spectacles at the baseline visit ( P = 0.0011 in SCL group; P = 0.0001 in RGPCL group), and at the follow-up visit, this significance was proven for the RGPCL group ( P = 0.001). Also, spectacle TV showed a significant improvement on the follow-up visit ( P = 0.0022 in SCL group; P = 0.0269 in RGPCL group). CONCLUSION Contact lens wear improves visual performance compared to spectacles. TV results showed superiority of CLs compared to the spectacles, without a statistical difference regarding the CL type.
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Affiliation(s)
- Iva Krolo
- University Department of Ophthalmology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Aida Kasumović Bećirević
- University Department of Ophthalmology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
- Eye Polyclinic Dr. Sefić, Sarajevo, Bosnia and Herzegovina
| | - Ivana Radman
- University Department of Ophthalmology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Ivan Sabol
- Ruđer Bošković Institute, Zagreb, Croatia
| | - Maja Malenica Ravlić
- University Department of Ophthalmology, University Hospital Center Sestre Milosrdnice, Zagreb, Croatia
| | - Mirko Ratković
- Department of Ophthalmology, NU Hospital Group, Uddevalla Hospital, Uddevalla, Sweden
| | - Mirna Belovari
- Optical Express, Hainault House, Tallaght, Dublin, Ireland
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Koh S, Maeda N, Terao M, Maeda H, Kosaki R, Kozaki J, Nishida K. Optical Quality and Visual Performance With Different Toric Contact Lens Designs. Eye Contact Lens 2023; 49:483-488. [PMID: 37713280 DOI: 10.1097/icl.0000000000001037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2023] [Indexed: 09/17/2023]
Abstract
OBJECTIVES To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance. METHODS Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared. RESULTS The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05). CONCLUSIONS Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.
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Affiliation(s)
- Shizuka Koh
- Department of Innovative Visual Science (S.K.), Osaka University Graduate School of Medicine, Osaka, Japan; Department of Ophthalmology (S.K., N.M., K.N.), Osaka University Graduate School of Medicine, Osaka, Japan; and Kozaki Eye Clinic (N.M., M.T., H.M., R.K., J.K.), Osaka, Japan
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Abdelazeem RM, Agour M. Optical inspection of single vision soft contact lenses based on an active adaptive wavefront sensor. APPLIED OPTICS 2022; 61:141-148. [PMID: 35200813 DOI: 10.1364/ao.441289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/28/2021] [Indexed: 06/14/2023]
Abstract
We present an experimental configuration for optical inspection of single vision soft contact lenses based on an active adaptive wavefront sensor. At first, the soft lenses were immersed in a saline filled wet cell to prevent surface deformation during measurements. Thereafter, refractive powers and aberrations were accurately measured before and after correcting illumination laser beam aberrations and wet cell-induced aberrations. The results reveal that there is a significant difference between the measured aberrations and refractive powers before and after aberration compensation. Accordingly, the proposed system is recommended as an optical inspection tool for precise assessment of commercially available contact lenses.
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Visual image quality after small-incision lenticule extraction compared with that of spectacles and contact lenses. J Cataract Refract Surg 2021; 47:731-740. [PMID: 33181632 DOI: 10.1097/j.jcrs.0000000000000501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/28/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE To assess the influence of small-incision lenticule extraction (SMILE) for high myopia on the visual image quality assessed by the logarithm of the visual Strehl ratio (logVSX) and put this into a clinical context by pairwise comparing the logVSX of postoperative eyes with those of myopic controls wearing spectacles and/or contact lenses. SETTING University hospital. DESIGN Prospective and cross-sectional clinical study. METHODS Patients with a myopic spherical equivalent of at least 6.00 diopters treated with SMILE aimed at emmetropia and correspondingly myopic controls corrected with spectacles and/or contact lenses were included. The logVSX calculation was divided into habitual logVSX based on the wavefront aberration measurement directly and optimal logVSX calculated in a theoretical through-focus experiment to obtain the best-achievable logVSX. RESULTS A total of 117 eyes of 61 patients and 64 eyes of 34 myopic controls were included. SMILE did not affect the habitual logVSX but worsened the optimal logVSX (P < .001). The postoperative habitual logVSX was statistically significantly worse compared with contact lenses (P = .002). The postoperative optimal logVSX was significantly worse compared with both spectacles (P < .01) and contact lenses (P = .003). There was no statistically significant difference in habitual or optimal logVSX between spectacles and contact lenses. CONCLUSIONS SMILE for high myopia does not affect the habitual logVSX but decreases the optimal logVSX slightly. The postoperative habitual logVSX is worse than for contact lenses but not spectacles, and the postoperative optimal logVSX is worse than for both contact lenses and spectacles. There is no statistically significant difference in either habitual or optimal logVSX between spectacles and contact lenses.
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Rae SM, Price HC. The effect of soft contact lens wear and time from blink on wavefront aberration measurement variation. Clin Exp Optom 2021; 92:274-82. [DOI: 10.1111/j.1444-0938.2009.00377.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Sheila M Rae
- Vision and Eye Research Unit, Anglia Ruskin University, Cambridge, United Kingdom
E‐mail:
| | - Holly C Price
- Vision and Eye Research Unit, Anglia Ruskin University, Cambridge, United Kingdom
E‐mail:
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Domínguez‐vicent A, Esteve‐taboada JJ, Ferrer‐blasco T, García‐lázaro S, Montés‐micó R. Optical quality comparison among different Boston contact lens materials. Clin Exp Optom 2021; 99:39-46. [DOI: 10.1111/cxo.12323] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 04/15/2015] [Accepted: 04/19/2015] [Indexed: 11/27/2022] Open
Affiliation(s)
| | | | - Teresa Ferrer‐blasco
- Optometry Research Group (GIO), Department of Optics, University of Valencia, Spain,
| | | | - Robert Montés‐micó
- Optometry Research Group (GIO), Department of Optics, University of Valencia, Spain,
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Atchison DA. Recent advances in measurement of monochromatic aberrations of human eyes. Clin Exp Optom 2021; 88:5-27. [PMID: 15658922 DOI: 10.1111/j.1444-0938.2005.tb06659.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Revised: 11/18/2004] [Accepted: 11/27/2004] [Indexed: 11/29/2022] Open
Abstract
The field of aberrations of the human eye is moving rapidly, being driven by the desire to monitor and optimise vision following refractive surgery. It is important for ophthalmologists and optometrists to have an understanding of the magnitude of various aberrations and how these are likely to be affected by refractive surgery and other corrections. In this paper, I consider methods used to measure aberrations, the magnitude of aberrations in general populations and how these are affected by various factors (for example, age, refractive error, accommodation and refractive surgery) and how aberrations and their correction affect spatial visual performance.
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Affiliation(s)
- David A Atchison
- School of Optometry, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia
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Macedo-de-Araújo RJ, Faria-Ribeiro M, McAlinden C, van der Worp E, González-Méijome JM. Optical Quality and Visual Performance for One Year in a Sample of Scleral Lens Wearers. Optom Vis Sci 2020; 97:775-789. [DOI: 10.1097/opx.0000000000001570] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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Sapkota K, Franco S, Lira M. Contrast sensitivity function with soft contact lens wear. JOURNAL OF OPTOMETRY 2020; 13:96-101. [PMID: 32063505 PMCID: PMC7182777 DOI: 10.1016/j.optom.2020.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 12/20/2019] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
PURPOSES To compare contrast sensitivity function (CSF) with soft contact lens (SCL) and spectacles wear. To investigate the effect of a three-month period of SCL wear on CSF. METHODS Forty-seven myopic subjects with no history of contact lens (CL) wear were included in this longitudinal prospective study. CSF was measured with spectacles using the CSV-1000 (VectorVision, Greenvile, OH). Subsequently, subjects were fitted with a daily disposable lens (Nelfilcon-A, Stenofilcon-A or Nesofilcon-A) in one eye and a monthly disposable lens (Lotrafilcon-B, Comfilcon-A or Balafilcon-A) in the other eye and wore the same type of CLs for three months. CSF was measured again on the same day and after three months wearing CLs. Differences in CSF with spectacles and CLs on baseline and changes to CSF after three months of CLs wear were assessed. The effect of lens materials and wearing modality on CSF change was also investigated. RESULTS CSF was higher with CLs in comparison to the values with spectacles for spatial frequencies of 3, 6 and 12 cycles per degree (cpd) (p<0.05) while there was no difference for spatial frequency of 18 cpd (p=0.114). No significant difference was found in the CSF with CLs between baseline and after three months of lens wear (p>0.05). There was no difference in CSF between hydrogel and silicone CLs as well as when comparing daily with monthly wear CLs (p>0.05). CONCLUSION CSF is better with CLs than with spectacles. CSF values with CL are similar between baseline and after 3 months of lens wear.
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Affiliation(s)
- Kishor Sapkota
- Center of Physics, University of Minho, Braga, Portugal.
| | - Sandra Franco
- Center of Physics, University of Minho, Braga, Portugal
| | - Madalena Lira
- Center of Physics, University of Minho, Braga, Portugal
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HIGHER-ORDER ABERRATIONS IN EYES WITH SILICONE OIL TAMPONADE. Retina 2019; 40:735-742. [PMID: 30640281 DOI: 10.1097/iae.0000000000002442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the changes in higher-order aberrations (HOAs) after silicone oil removal and to evaluate their associations with visual acuity. METHODS Fifty-nine eyes of 58 patients who underwent SO removal were included. Total, corneal, and internal optic HOAs, and best-corrected visual acuity were measured before and 1 month after SO removal, and changes were compared between phakic and pseudophakic eyes. RESULTS Total ocular and internal optic HOAs decreased significantly after SO removal both in pseudophakic (n = 40, all P < 0.001) and phakic eyes (n = 19, P = 0.017, P = 0.004). Preoperative HOAs (P < 0.001) and changes in HOAs (P = 0.006) were greater in pseudophakic eyes than in phakic eyes. Best-corrected visual acuity was significantly improved after SO removal, from 20/105 to 20/78 (P < 0.001) in pseudophakic eyes, whereas there was no difference in phakic eyes (P = 0.714). Preoperative HOAs and the reduction in HOAs after SO removal were greater in best-corrected visual acuity-improved eyes than best-corrected visual acuity-unchanged eyes (P < 0.001). CONCLUSION Silicone oil tamponade induced an increase in HOAs, and these increases were greater in pseudophakic eyes than in phakic eyes. Silicone oil may cause additional visual impairments because of HOAs, beyond those caused by retinal diseases, particularly in pseudophakic eyes.
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Clinical Evaluation of Large Diameter Rigid-Gas Permeable Versus Soft Toric Contact Lenses for the Correction of Refractive Astigmatism. A MultiCenter Study. Eye Contact Lens 2018; 44:164-169. [PMID: 27898516 DOI: 10.1097/icl.0000000000000323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This study aims to address the clinical performance of a large diameter rigid gas permeable lens (LRGP) in a group of subjects with low-to-moderate (0.75-2.75 D) refractive astigmatism. An additional goal was to determine whether soft toric or LRGP contact lenses performed better objectively in the correction of astigmatism and to determine which modality is preferred by subjects. METHODS This was a multisite prospective cross-over clinical study. Ten asymptomatic contact lens wearers per site (four university clinics) were recruited and randomly assigned to group A or group B. Group A was assigned to start wearing Comfilcon A soft toric lens first, for two weeks, and then crossed over to LRGP lenses (Boston XO, 14.3 mm diameter miniscleral lens). Group B initially wore LRGP lenses and then crossed over to soft toric lenses. For each type of lens worn, low-contrast and high-contrast visual acuity (VA) were evaluated at distance. At the conclusion of the study, after two months, all subjects completed a questionnaire in which they were asked to indicate their preference for one type of lens (soft toric or LRGP) and to rate the quality of vision in day-to-day activities. RESULTS Thirty-six of 38 (94.7%) subjects completed the study with 75% preferring the vision of the LRGP lens as compared to the soft toric lenses worn in the study. 52.7% expressed a preference to continue with this modality despite only 38.8% reporting that these LRGP lenses are easy or very easy to handle. Wear time, subjective comfort, and subjective vision ratings exhibited no significant difference between the two groups. CONCLUSIONS In a population of asymptomatic contact lens wearers, LRGP lenses can be considered as a good alternative to soft toric lenses for the correction of refractive astigmatism.
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Yang F, Gu H, Li M, Cai J, Zhou Q, Lam WK. The impact on human visual performance when viewing 2-D and 3-D movies. Technol Health Care 2018; 26:79-86. [PMID: 29689756 PMCID: PMC6004945 DOI: 10.3233/thc-174206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE: To examine the human visual performance (wavefront aberration) and subjective questionnaire (SQ) of visual fatigue when viewing 2-D and 3-D movies. METHODS: Thirty healthy adults observed 2-D and 3-D movies on the same television from a 3m distances during 2D, 3D-A (with better 3D glasses), and 3D-B (with poorer 3D glasses) viewing conditions. Visual quality index, including modulation transfer function index (MTFI), higher order aberration root mean square (RMS), vertical coma (VC), horizontal coma (HC) and spherical aberration (SA), were assessed before and after each viewing condition. One-way repeated measures ANOVA was performed to assess the changes of each test variable before and after movie viewing. RESULTS: Participants watching movies with 3D-B conditions experienced higher change of MTFI, RMS, VC and HC but smaller SQ, compared with 2D and 3D-A (P< 0.05). Additionally, higher MTFI but smaller SQ was found for 3D-A compared with 2D viewing condition (P< 0.05). CONCLUSIONS: While prolonged viewing 2-D and 3-D movies would lead to poorer visual performance, 3-D glasses with better quality can play the major role in reducing visual ability for users. The change of human eye wavefront aberration might be useful for the evaluation of visual fatigue in the future.
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Affiliation(s)
- Fan Yang
- School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China.,Li Ning Sports Science Research Center, Beijing, China
| | - Huiru Gu
- National Research Center for Rehabilitation Technical Aids, Beijing, China.,Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Beijing, China.,Key Laboratory of Rehabilitation Technical Aids Analysis and Identification of the Ministry of Civil Affairs, Beijing, China
| | - Man Li
- National Research Center for Rehabilitation Technical Aids, Beijing, China.,Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Beijing, China.,Key Laboratory of Rehabilitation Technical Aids Analysis and Identification of the Ministry of Civil Affairs, Beijing, China
| | - Jianqi Cai
- China National Institute of Standardization, Beijing, China
| | - Qianxiang Zhou
- School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Wing-Kai Lam
- Li Ning Sports Science Research Center, Beijing, China
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Jiang Y, Wang Y, Zhang J, Chen X, Li L, Zhao H, Wang R, Dai Y. Dynamic changes in higher-order aberrations after correction of lower-order aberrations with adaptive optics in myopic and emmetropic eyes. APPLIED OPTICS 2018; 57:514-520. [PMID: 29400801 DOI: 10.1364/ao.57.000514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
This study investigated the instantaneous changes of higher-order aberrations (HOAs) following lower-order aberrations (LOAs) correction with a closed-loop adaptive optics (AO) system in myopic and emmetropic eyes. Data were analyzed using generalized additive mixed models. Time-related changes in HOAs were modeled with two-piecewise linear regressions and were compared between myopic and emmetropic eyes. Both vertical coma and spherical aberrations shifted to the positive direction immediately after LOA correction. The fluctuations of the above values were significantly faster in myopic than in emmetropic eyes. Understanding these changes in HOAs following LOA correction may help in achieving better visual outcomes.
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Papadatou E, Del Águila-Carrasco AJ, Esteve-Taboada JJ, Madrid-Costa D, Cerviño-Expósito A. Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses. Int J Ophthalmol 2017; 10:103-108. [PMID: 28149785 DOI: 10.18240/ijo.2017.01.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/18/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses. METHODS Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device (LAMBDA-X, Belgium). Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance (far, intermediate, and near) and pupil size was also analyzed. RESULTS The power distribution of the lenses was affected by pupil size differently. One of the lenses showed a significant spread in refractive power distribution, from about -3 D to 0 D. Generally, the power distribution of the lenses expanded as the pupil diameter became greater. The surface of the lens dedicated for each distance varied substantially with the design of the lens. CONCLUSION In an experimental basis, our results show how the lenses power distribution is affected by the pupil size and underlined the necessity of careful evaluation of the patient's visual needs and the optical properties of a multifocal contact lens for achieving the optimal visual outcome.
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Affiliation(s)
- Eleni Papadatou
- Optometry Research Group, University of Valencia, Valencia 46100, Spain
| | | | | | - David Madrid-Costa
- Optics II Department, Optics and Optometry Faculty, Complutense University of Madrid, Madrid 28037, Spain
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Clinical Performance of a Spherical Hybrid Lens Design in High Regular Astigmatism. Eye Contact Lens 2016; 44 Suppl 1:S66-S70. [PMID: 27660920 DOI: 10.1097/icl.0000000000000326] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate safety, efficacy, and comfort of a spherical hybrid contact lens design in management of the regular astigmatic cornea. METHODS This prospective study included 18 eyes from 18 subjects with regular corneal astigmatism greater than -3.00 diopters. All patients were fitted with optimal hybrid contact lenses. Demographic data and fitting parameters were recorded. Patient refraction, visual outcomes, contrast sensitivity, and glare levels were measured 2 weeks, 3 months, and 6 months after the start of lens use. Duration of lens use, comfort grades, causes of lens discontinuation, and any noticed complications were recorded. RESULTS An average of 1.8 lenses (range 1-3) was required to achieve the optimal fit. Average logMAR visual acuity had improved significantly from 0.92±0.03 to 0.03±0.04 (P<0.001) at the last follow-up. Contrast sensitivity and glare tests were also significantly improved. Statistical analysis of the subjective responses indicated a strong acceptance of the lens by most of the patients. Mean wearing time of lenses was 10.1±3.2 hr/d. Causes of discontinuation were discomfort (2 patients), high lens price (2 patients), and handling problems (1 patient). Minimal complications were demonstrated in wearers of the lenses during follow-up visits. CONCLUSION Spherical hybrid contact lenses provide a good option for patients with regular astigmatic corneas. They provide optimal visual function with high comfort and patient satisfaction, especially when surgery is undesirable or contraindicated.
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Alipour F, Rahimi F, Hashemian MN, Ajdarkosh Z, Roohipoor R, Mohebi M. Mini-scleral Contact Lens for Management of Poor Visual Outcomes after Intrastromal Corneal Ring Segments Implantation in Keratoconus. J Ophthalmic Vis Res 2016; 11:252-7. [PMID: 27621780 PMCID: PMC5000525 DOI: 10.4103/2008-322x.188400] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Purpose: To evaluate the feasibility and efficacy of mini-scleral design (MSD) contact lenses to treat keratoconus patients who were unsatisfied with the results of corneal inlay. Methods: In this prospective interventional case series, 9 eyes of 6 keratoconus patients who were unsatisfied with the results of corneal inlay were fitted with MSD contact lenses. Demographic data, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and higher order aberrations (HOAs) were evaluated before contact lens fitting. Corrected visual acuity by placing the MSD contact lens with or without over-refraction, and HOAs were measured one hour after contact lens fitting. One month after contact lens wearing, corrected visual acuity by placing the MSD contact lens with over-refraction and possible contact lens related problems were assessed. Ocular comfort and contact lens handling problems were asked in follow-up visits. The data was analyzed using descriptive statistical tests. Results: Nine eyes of 6 patients were successfully fitted with the mini-scleral lens. Fitting was ideal in 7 eyes and acceptable in 2 eyes. Mean corrected visual acuity by placing the MSD lens without over-refraction was 0.09 (range, 0.00-0.15) LogMAR which was significantly better than the mean BSCVA of 0.38 (range, 0.2-0.6) LogMAR (P = 0.007). The mean root mean square (RMS) of third-order coma and trefoil significantly decreased after MSD contact lens fitting (P = 0.012 and P = 0.015, respectively); however, changes in the fourth-order spherical aberration were not statistically significant (P = 0.336). Conclusion: Mini-scleral contact lenses may be helpful in the management of visually unsatisfied patients after corneal inlay.
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Affiliation(s)
- Fatemeh Alipour
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Firoozeh Rahimi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Zahra Ajdarkosh
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ramak Roohipoor
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoumeh Mohebi
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Assessment of aberrations and visual quality differences between myopic and astigmatic eyes before and after contact lens application. North Clin Istanb 2015; 2:1-6. [PMID: 28058332 PMCID: PMC5175044 DOI: 10.14744/nci.2015.87487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 02/24/2015] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE: To evaluate the aberration and visual quality differences between myopic and astigmatic eyes before and after contact lens application by using corneal aberrometer and low- contrast sensitivity chart. METHODS: Eighty eyes of 40 patients were included in this study. Patients were divided into two groups as myopic (40 eyes, n=20) and astigmatic groups (40 eyes, n=20). We used aspheric Balafilcon A (Purevision and Purevision Toric Bausch&Lomb, Rochester, USA) lenses for each group. Corneal aberrations and low-contrast sensitivity values were measured and compared for each patient in both groups. RESULTS: There were no statistically significant differences between myopic and astigmatic groups when we compared low-contrast sensitivity values for both on- and off-eyes. Mean total higher-order aberration (HOA) values for off-eye, were 0.29±0.10 μm, and 0.33±0.10 μm for on-eye in the myopic group, while they were 0.42±0.14 μm in off-eye and 0.37±0.23 μm in on-eye in the astigmatic group. Off-eye mean coma, irregular astigmatism and total higher-order aberration RMS (root-mean-square) values were significantly higher in the astigmatic group compared to the myopic group (p=0.006, p=0.001, p=0.001) but mean on-eye RMS values were not. CONCLUSION: Myopic and astigmatic patients differ in terms of high-order aberrations and these differences cannot be equalized after contact lens application, but visual quality can be improved in both patients by using contact lenses.
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Contrast sensitivity function after correcting residual wavefront aberrations during RGP lens wear. Optom Vis Sci 2015; 91:1271-7. [PMID: 24770353 DOI: 10.1097/opx.0000000000000253] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate the effect on the contrast sensitivity function (CSF) of correcting the residual wavefront aberrations in myopic and keratoconic subjects wearing rigid gas permeable (RGP) contact lenses. METHODS Seventeen eyes of 16 myopic subjects and 20 eyes of 19 keratoconic subjects were included in this study. All eyes were habitually corrected with RGP lenses. The residual aberrations of the RGP lens-wearing eyes were compensated by an adaptive optics (AO) system. The contrast sensitivities were measured through a 4-mm artificial pupil at spatial frequencies of 2, 4, 8, 16, and 32 cycles per degree (cpd) during RGP lens wear for the myopic and keratoconic groups, respectively. The CSF measurements were repeated with and without AO correction. Comparisons of contrast sensitivity at all spatial frequencies with and without AO correction were performed respectively for the myopic and keratoconic groups during RGP lens wear. RESULTS In the myopic RGP lens-wearing group, the differences in contrast sensitivity at each spatial frequency, with and without AO correction, were not significant (all p values > 0.05). In the keratoconic RGP lens-wearing group, the contrast sensitivities at all spatial frequencies with AO correction were higher than those without AO correction, but differences only at the low (2 cpd) and intermediate (4, 8, and 16 cpd) spatial frequencies were significant (p = 0.039, 0.005, 0.001, and 0.007). CONCLUSIONS The residual aberrations significantly reduced the contrast sensitivities at low and intermediate spatial frequencies for keratoconic RGP lens-wearing eyes but did not have any effect on the CSF for the myopic RGP lens-wearing eyes. Developing techniques that could more completely correct the wavefront aberrations may improve visual performance in keratoconus.
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Rodriguez-Vallejo M, Benlloch J, Pons A, Monsoriu JA, Furlan WD. The effect of fractal contact lenses on peripheral refraction in myopic model eyes. Curr Eye Res 2014; 39:1151-60. [PMID: 24749733 DOI: 10.3109/02713683.2014.903498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To test multizone contact lenses in model eyes: Fractal Contact Lenses (FCLs), designed to induce myopic peripheral refractive error (PRE). METHODS Zemax ray-tracing software was employed to simulate myopic and accommodation-dependent model eyes fitted with FCLs. PRE, defined in terms of mean sphere M and 90°-180° astigmatism J180, was computed at different peripheral positions, ranging from 0 to 35° in steps of 5°, and for different pupil diameters (PDs). Simulated visual performance and changes in the PRE were also analyzed for contact lens decentration and model eye accommodation. For comparison purposes, the same simulations were performed with another commercially available contact lens designed for the same intended use: the Dual Focus (DF). RESULTS PRE was greater with FCL than with DF when both designs were tested for a 3.5 mm PD, and with and without decentration of the lenses. However, PRE depended on PD with both multizone lenses, with a remarkable reduction of the myopic relative effect for a PD of 5.5 mm. The myopic PRE with contact lenses decreased as the myopic refractive error increased, but this could be compensated by increasing the power of treatment zones. A peripheral myopic shift was also induced by the FCLs in the accommodated model eye. In regard to visual performance, a myopia under-correction with reference to the circle of least confusion was obtained in all cases for a 5.5 mm PD. The ghost images, generated by treatment zones of FCL, were dimmer than the ones produced with DF lens of the same power. CONCLUSIONS FCLs produce a peripheral myopic defocus without compromising central vision in photopic conditions. FCLs have several design parameters that can be varied to obtain optimum results: lens diameter, number of zones, addition and asphericity; resulting in a very promising customized lens for the treatment of myopia progression.
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Chakraborty R, Read SA, Collins MJ. Diurnal variations in ocular aberrations of human eyes. Curr Eye Res 2013; 39:271-81. [PMID: 24143963 DOI: 10.3109/02713683.2013.841257] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate the diurnal variations in ocular wavefront aberrations over two consecutive days in young adult subjects. MATERIALS AND METHODS Measurements of both lower-order (sphero-cylindrical refractive powers) and higher-order (third and fourth-order aberration terms) ocular aberrations were collected for 30 young adult subjects at 10 different times over two consecutive days using a Hartmann-Shack aberrometer. Seventeen subjects were myopic and 13 were emmetropic. Five sets of measurements were collected each day at approximately 3 hourly intervals, with the first measurement taken at ∼9 am and the final measurement at ∼9 pm. RESULTS Spherical equivalent refraction (p = 0.029) and spherical aberration (p = 0.043) were both found to undergo significant diurnal variation over the two measurement days. The spherical equivalent was typically found to be at a maximum (i.e. most hyperopic) at the morning measurement, with a small myopic shift of 0.37 ± 0.15 D observed over the course of the day. The mean spherical aberration of all subjects (0.038 ± 0.048 μm) was found to be positive during the day and gradually became more negative into the evening, with a mean amplitude of change of 0.036 ± 0.02 μm. None of the other considered sphero-cylindrical refractive power components or higher-order aberrations exhibited significant diurnal variation over the two days of the experiment (p > 0.05). Except for the lower-order astigmatism at 90/180 degree (p = 0.040), there were no significant differences between myopes and emmetropes in the magnitude and timing of the observed diurnal variations (p > 0.05). CONCLUSIONS Significant diurnal variations in spherical equivalent and spherical aberration were consistently observed over two consecutive days of measurement. Research and clinical applications requiring precise refractive error and wavefront measurements should take these diurnal changes into account when interpreting wavefront data.
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Affiliation(s)
- Ranjay Chakraborty
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology , Brisbane, Queensland , Australia
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Abstract
PURPOSE To investigate the feasibility of correcting ocular higher order aberrations (HOAs) in keratoconus (KC) using wavefront-guided optics in a scleral lens prosthetic device (SLPD). METHODS Six advanced KC patients (11 eyes) were fitted with an SLPD with conventional spherical optics. A custom-made Shack-Hartmann wavefront sensor was used to measure aberrations through a dilated pupil wearing the SLPD. The position of SLPD, that is, horizontal and vertical decentration relative to the pupil and rotation were measured and incorporated into the design of the wavefront-guided optics for the customized SLPD. A submicron-precision lathe created the designed irregular profile on the front surface of the device. The residual aberrations of the same eyes wearing the SLPD with wavefront-guided optics were subsequently measured. Visual performance with natural mesopic pupil was compared between SLPDs having conventional spherical and wavefront-guided optics by measuring best-corrected high-contrast visual acuity and contrast sensitivity. RESULTS Root mean square of HOA in the 11 eyes wearing conventional SLPD with spherical optics was 1.17 ± 0.57 μm for a 6-mm pupil. Higher order aberrations were effectively corrected by the customized SLPD with wavefront-guided optics, and root mean square was reduced 3.1 times on average to 0.37 ± 0.19 μm for the same pupil. This correction resulted in significant improvement of 1.9 lines in mean visual acuity (p < 0.05). Contrast sensitivity was also significantly improved by factors of 2.4, 1.8, and 1.4 on average for 4, 8, and 12 cycles/degree, respectively (p < 0.05 for all frequencies). Although the residual aberration was comparable to that of normal eyes, the average visual acuity in logMAR with the customized SLPD was 0.21, substantially worse than normal acuity. CONCLUSIONS The customized SLPD with wavefront-guided optics corrected the HOA of advanced KC patients to normal levels and improved their vision significantly.
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Kaczmarek JC, Tieppo A, White CJ, Byrne ME. Adjusting biomaterial composition to achieve controlled multiple-day release of dexamethasone from an extended-wear silicone hydrogel contact lens. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2013; 25:88-100. [DOI: 10.1080/09205063.2013.840228] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
PURPOSE The purpose of this study is to compare the visual performance provided by different daily disposable contact lenses and to analyze its variation over time. METHODS Visual performance was evaluated in terms of visual acuity (VA) and contrast sensitivity (CS) in 15 myopic subjects (-0.50 to -4.00 diopters) who had been previously fitted with each one of the following seven types of soft contact lenses: DAILIES TOTAL1 (Alcon, Forth Worth, TX), DAILIES AquaComfort Plus (Alcon), 1-DAY ACUVUE TruEye (Johnson & Johnson Vision Care, Jacksonville, FL), 1-DAY ACUVUE MOIST (Johnson & Johnson Vision Care), SofLens daily disposable (Bausch & Lomb, Rochester, NY), Proclear 1 Day (CooperVision, Fairport, NY), and Clariti 1-Day (Sauflon, Twickenham, United Kingdom). We measured VA at three contrast levels (10%, 50%, and 100%) and CS for three spatial frequencies (10, 20, and 25 cycles/degree). These measurements were performed at 2-hr intervals during a 12-hr period of continuous wearing. Measurements were also performed with ophthalmic lenses before contact lens fitting. RESULTS Two-way analysis of variance (ANOVA) results revealed significant differences across the lens types and over time for low-contrast VA only. For high- and medium-contrast VA, ophthalmic lens performed better than the contact lenses after 12 hr of use (without statistical differences among the contact lenses). Contrast sensitivity values also showed differences across lenses for the three spatial frequencies under analysis. For each particular lens type, no CS variations were observed with wearing time. Although some of the differences were not statistically significant, we found that, for many of the VA and CS measures, ophthalmic lens and DAILIES TOTAL1 yielded better values than the 1-DAY ACUVUE TruEye and Clariti 1-Day. CONCLUSIONS Assessing VA at different contrasts and CS measurements allowed us to perform a visual function evaluation. Contact lens characteristics such as material and water content, among others, may be the cause of the differences in visual performance that emerged from this study. Our findings provide useful information for contact lens practitioners.
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Montés-Micó R, Belda-Salmerón L, Ferrer-Blasco T, Albarrán-Diego C, García-Lázaro S. On-eye optical quality of daily disposable contact lenses for different wearing times. Ophthalmic Physiol Opt 2013; 33:581-91. [DOI: 10.1111/opo.12044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/07/2013] [Indexed: 12/01/2022]
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Abstract
PURPOSE Contact lenses (CLs) reduced the degree of hyperopic field curvature present in myopic eyes and rigid CLs reduced spherocylindrical image blur on the peripheral retina, but their effect on higher order aberrations and overall optical quality of the eye in the peripheral visual field is still unknown. The purpose of our study was to evaluate peripheral wavefront aberrations and image quality across the visual field before and after CL correction. METHODS A commercial Hartmann-Shack aberrometer was used to measure ocular wavefront errors in 5° steps out to 30° of eccentricity along the horizontal meridian in uncorrected eyes and when the same eyes are corrected with soft or rigid CLs. Wavefront aberrations and image quality were determined for the full elliptical pupil encountered in off-axis measurements. RESULTS Ocular higher order aberrations (HOA) increase away from fovea in the uncorrected eye. Third-order aberrations are larger and increase faster with eccentricity compared with the other HOA. CLs increase all HOA except third-order Zernike terms. Nevertheless, a net increase in image quality across the horizontal visual field for objects located at the foveal far point is achieved with rigid lenses, whereas soft CLs reduce image quality. CONCLUSIONS Second-order aberrations limit image quality more than HOA in the periphery. Although second-order aberrations are reduced by CLs, the resulting gain in image quality is partially offset by increased amounts of HOA. To fully realize the benefits of correcting HOA in the peripheral field requires improved correction of second-order aberrations as well.
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Jinabhai A, Radhakrishnan H, Tromans C, O’Donnell C. Visual performance and optical quality with soft lenses in keratoconus patients. Ophthalmic Physiol Opt 2012; 32:100-16. [DOI: 10.1111/j.1475-1313.2011.00889.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Tan G, Yang J, Chen X, He H, Zhong X. Changes in wave-front aberrations after rigid gas permeable contact lens fitting in post-laser in situ keratomileusis patients with visual complaints. Can J Ophthalmol 2010; 45:264-8. [PMID: 20436548 DOI: 10.3129/i09-268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
OBJECTIVE To evaluate the effect of rigid gas permeable (RGP) contact lenses in reducing wave-front aberrations in post-laser in situ keratomileusis (LASIK) myopic patients. DESIGN Cross-sectional study. PARTICIPANTS Thirty patients with visual complaints after conventional LASIK procedure for correcting myopia. METHODS The 30 patients were fitted with RGP contact lenses. Wave-front measurements were taken before and after RGP contact lens wearing. RESULTS Compared with bare eye examinations, root mean-square values of higher-order aberrations (HOAs) significantly decreased with RGP contact lens use. Among these, spherical aberration decreased from 0.507 (SD 0.304) microm to 0.164 (SD 0.121) microm (t = 7.186, p < 0.001); coma decreased from 0.470 (SD 0.312) microm to 0.165 (SD 0.090) microm (t = 5.566, p < 0.001); secondary coma decreased from 0.079 (SD 0.050) microm to 0.044 (SD 0.027) m (t = 4.118, p < 0.001); and total HOAs decreased from 0.782 (SD 0.449) microm to 0.307 (SD 0.140) microm (t = 6.710, p < 0.001). CONCLUSIONS Fitting RGP contact lenses effectively decreased HOAs induced by conventional myopic LASIK surgery. Possible reasons may be the elimination of irregularity and dissymmetry on the corneal anterior surface, relief of the aspherical extent of the central corneal surface, and enlargement of the effective optical zone.
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Affiliation(s)
- Gan Tan
- Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China
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Keir N, Simpson T, Fonn D. Visual and optical performance of silicone hydrogel contact lenses for moderate myopia. JOURNAL OF OPTOMETRY 2010; 3:149-157. [PMCID: PMC3974284 DOI: 10.1016/s1888-4296(10)70021-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 09/07/2010] [Indexed: 06/10/2023]
Abstract
Purpose To compare the short-term visual and optical performance of silicone hydrogel contact lenses for myopia ≥ −3.00D. Methods This was a short-term, non-dispense, double-masked, randomized study investigating Night&Day (ND), PureVision (PV), O2 Optix (O2), Biofinity (BF), Acuvue Advance (AA) and Acuvue OASYS for myopia ≥ −3.00D. Testing was conducted under scotopic conditions. Measures (one eye only) included: high- and low-contrast visual acuity (HCVA/LCVA), contrast sensitivity, subjective clarity of vision ratings (0-100 scale using reference images, with test image representing grade 50) and ocular aberrations (up to the 4th order, analyzed across individual scotopic pupil sizes). Results Three males and 27 females participated, with a mean (± SD) age of 24.9 ± 7.7 yrs (range 19 to 53 yrs), sphere of −5.30 ± 1.73D (range −3.00 to −10.75D) and cylinder −0.36 ± 0.23D (range 0 to −0.75D). Mean (± SEM) logMAR HCVA ranged from 0.06 (PV) to 0.10 (AA) (± 0.02), LCVA from 0.33 (BF) to 0.40 (AA) (± 0.02) and contrast sensitivity from 2.33 (BF) to 2.53 (ND) (± 0.15) (differences not statistically significant; all p > 0.05). Subjective ratings for the test image ranged from 59 (PV) to 64 (ND) (± 4) and 56 (AA) to 65 (ND) (± 4), for monochromatic and polychromatic reference images, respectively (all p > 0.05). There was a statistically significant impact on ocular aberrations with all study lenses compared to no lens. Between-lens differences were statistically significant for defocus (Z02), horizontal coma (Z 13) and spherical aberration (Z04). Conclusions Despite some differences in ocular aberrations, there were no significant differences in HCVA, LCVA, contrast sensitivity or subjective ratings across lenses.
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Affiliation(s)
- Nancy Keir
- Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada
| | - Trefford Simpson
- School of Optometry, University of Waterloo, Waterloo, ON, Canada
| | - Desmond Fonn
- Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada
- School of Optometry, University of Waterloo, Waterloo, ON, Canada
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Tan G, Chen X, Xie RZ, He H, Liu Q, Guo Y, Liao A, Zhong X. Reverse geometry rigid gas permeable contact lens wear reduces high-order aberrations and the associated symptoms in post-LASIK patients. Curr Eye Res 2010; 35:9-16. [PMID: 20021249 DOI: 10.3109/02713680903421186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE This study evaluated the efficacy of custom-made reverse geometry rigid gas permeable (RGP) contact lenses in the control of symptoms related to increased wavefront aberrations after LASIK correction of myopia. MATERIALS AND METHODS Twenty-eight myopes treated with LASIK were assessed for post-LASIK symptoms (declined night vision, glare, halos and/or monocular diplopia) and corneal topography. A set of RGP contact lenses was selected as trial lenses based on the matching between the lens and the patient's corneal topography. If the fluorescein pattern between the trial lens and the corneal surface showed a central alignment, a mid-peripheral bearing and peripheral clearance and if the patient felt comfortable with the lens wear, a duplicated lens was ordered for the patient. Otherwise, a lens satisfied with corneal topography of the patient and clinical judgment was used. Visual acuity (VA) and wavefront aberrations were measured after the lens wear. RESULTS The custom-made lenses well matched the host cornea with no dislodgment in all subjects. The post-LASIK eyes showed an increase of 1 Snellen line in VA (from 0.90 +/- 0.33 to 1.11 +/- 0.24) and a significant improvement in all symptoms after the lens wear. The total higher-order aberration is significantly reduced after the lens wear with at least 70% reduction in either spherical aberration, coma, third or fourth aberration but only 33% reduction in the fifth aberration. CONCLUSIONS Reverse geometry RGP lenses with the design based on individual topographic data can improve visual performance of post-LASIK eyes by reducing higher order aberrations.
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Affiliation(s)
- Gang Tan
- Zhongshan Ophthalmic Center and State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, China
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Joannes L, Hough T, Hutsebaut X, Dubois X, Ligot R, Saoul B, Van Donink P, De Coninck K. The reproducibility of a new power mapping instrument based on the phase shifting schlieren method for the measurement of spherical and toric contact lenses. Cont Lens Anterior Eye 2010; 33:3-8. [DOI: 10.1016/j.clae.2009.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 11/01/2009] [Accepted: 11/02/2009] [Indexed: 10/20/2022]
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Rae SM, Allen PM, Radhakrishnan H, Theagarayan B, Price HC, Sailaganathan A, Calver RI, O’Leary DJ. Increasing negative spherical aberration with soft contact lenses improves high and low contrast visual acuity in young adults. Ophthalmic Physiol Opt 2009; 29:593-601. [DOI: 10.1111/j.1475-1313.2009.00678.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
PURPOSE To determine the on-eye effect of spherical and toric contact lens design on higher-order aberrations (HOA). METHODS Thirty eyes (15 subjects) entered a masked, randomized, cross-over study. Each eye was fitted with the spherical and toric lens of the following brands in random order: Acuvue Advance, Biomedics 55, Frequency 55, and SofLens 66. HOAs were measured using the Zywave II Aberrometer over a 6-mm aperture up to fifth order. A linear model accounting for the fixed effect of lens type and random effects of subject and eye was created. Paired t-tests were completed between lens brands within the spherical and toric lenses and between the spherical and toric lens within each brand. Best-corrected visual acuity (VA) was measured and compared. RESULTS No clinically meaningful differences in total HOAs were found between brands or between the spherical and toric lens within a brand. Positive spherical aberration (SA) was reduced by all spherical and toric lenses compared to wearing no lens by 0.07 to 0.23 microm (p < 0.0001). Frequency toric induced the greatest change in SA. The thin-zone design lens (Acuvue Advance for Astigmatism) had a statistically different amount of vertical coma (-0.04 microm) than the three prism-balast toric lenses (0.11 to 0.23 microm; p < 0.0001). SofLens toric had the greatest amount of vertical coma, but better VA than Acuvue Advance for Astigmatism and Frequency toric. With the exception of Acuvue Advance for Astigmatism, toric lenses had greater absolute magnitude of vertical coma than their sphere counterparts (all p < 0.002). No other significant HOA differences were observed. CONCLUSIONS Toric contact lenses with prism-ballast designs demonstrated more vertical coma, but better VA. Positive SA was reduced by spherical and toric contact lenses. The visual quality effect of lens design and material on induced HOAs warrants further investigation.
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Wei X, Van Heugten T, Thibos L. Validation of a Hartmann-Moiré wavefront sensor with large dynamic range. OPTICS EXPRESS 2009; 17:14180-5. [PMID: 19654829 DOI: 10.1364/oe.17.014180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
UNLABELLED Our goal was to validate the accuracy, repeatability, sensitivity, and dynamic range of a Hartmann-Moiré (HM) wavefront sensor (PixelOptics, Inc.) designed for ophthalmic applications. METHODS Testing apparatus injected a 4 mm diameter monochromatic (532 nm) beam of light into the wavefront sensor for measurement. Controlled amounts of defocus and astigmatism were introduced into the beam with calibrated spherical (-20D to + 18D) and cylindrical (-8D to + 8D) lenses. Repeatability was assessed with three repeated measurements within a 2-minute period. RESULTS Correlation coefficients between mean wavefront measurements (n = 3) and expected wavefront vergence for both sphere and cylinder lenses were >0.999. For spherical lenses, the sensor was accurate to within 0.1D over the range from -20D to + 18D. For cylindrical lenses, the sensor was accurate to within 0.1D over the range from -8D to + 8D. The primary limitation to demonstrating an even larger dynamic range was the increasingly critical requirements for optical alignment. Sensitivity to small changes of vergence was constant over the instrument's full dynamic range. Repeatability of measurements for fixed condition was within 0.01D. CONCLUSION The Hartmann-Moiré wavefront sensor measures defocus and astigmatism accurately and repeatedly with good sensitivity over a large dynamic range required for ophthalmic applications.
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Affiliation(s)
- Xin Wei
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA.
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Katsoulos C, Karageorgiadis L, Vasileiou N, Mousafeiropoulos T, Asimellis G. Customized hydrogel contact lenses for keratoconus incorporating correction for vertical coma aberration. Ophthalmic Physiol Opt 2009; 29:321-9. [DOI: 10.1111/j.1475-1313.2009.00645.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Affiliation(s)
- Naoyuki Maeda
- Department of Ophthalmology, Osaka University Medical School, Osaka, Japan.
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Influence of cosmetically tinted soft contact lenses on higher-order wavefront aberrations and visual performance. Graefes Arch Clin Exp Ophthalmol 2008; 247:225-33. [PMID: 18953556 DOI: 10.1007/s00417-008-0973-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 09/27/2008] [Accepted: 10/06/2008] [Indexed: 10/21/2022] Open
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Chen M, Yoon G. Posterior corneal aberrations and their compensation effects on anterior corneal aberrations in keratoconic eyes. Invest Ophthalmol Vis Sci 2008; 49:5645-52. [PMID: 18641282 DOI: 10.1167/iovs.08-1874] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize posterior corneal aberrations in keratoconic (KC) eyes and investigate compensatory effects between anterior and posterior corneal surfaces. METHODS The corneal topography of 113 eyes (37 advanced KC, 31 moderate KC, 14 mild KC, and 31 normal eyes) was used to compute the corneal aberrations. The central 6-mm diameter of both anterior and posterior corneal topographies was decomposed into Zernike polynomials. The magnitude and the orientation of each posterior corneal aberration were calculated by vector analysis. The compensation effects between anterior and posterior corneal aberrations were also assessed quantitatively with a linear regression model. RESULTS The average higher order RMS wavefront errors for the posterior corneas were 1.04, 0.54, 0.24, and 0.19 microm in the advanced, moderate, and mild KC and normal eyes, respectively. In the advanced KC eyes, posterior corneal coma was oriented in the superior-nasal direction with a mean orientation angle of 75 degrees +/- 19 degrees OD and 78 degrees +/- 20 degrees OS. On average, 22%, 24%, and 14% of the anterior corneal coma were compensated by the posterior cornea in the advanced, moderate, and mild KC eyes, respectively. However, no significant higher order aberration (HOA) compensation effects were found in normal corneas. CONCLUSIONS Significantly larger amounts of posterior corneal aberrations and stronger compensation effects were observed in KC eyes than in normal eyes. The uncorrected posterior corneal aberration in KC eyes was substantial and degraded retinal image quality. This may explain the relatively poor visual acuity obtained in eyes with rigid gas permeable (RGP) lenses, which correct only anterior corneal aberrations.
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Affiliation(s)
- Minghan Chen
- Center for Visual Science, Department of Ophthalmology, Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
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Efron S, Efron N, Morgan PB. Repeatability and reliability of ocular aberration measurements in contact lens wear. Cont Lens Anterior Eye 2008; 31:81-8. [DOI: 10.1016/j.clae.2007.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/10/2007] [Accepted: 10/21/2007] [Indexed: 12/01/2022]
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Hyper Oxygen-Permeable Rigid Contact Lenses as an Alternative for the Treatment of Pediatric Aphakia. Eye Contact Lens 2008; 34:84-93. [DOI: 10.1097/icl.0b013e31811eadaa] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Koh S, Maeda N, Hamano T, Hirohara Y, Mihashi T, Hori Y, Hosohata J, Fujikado T, Tano Y. Effect of Internal Lubricating Agents of Disposable Soft Contact Lenses on Higher-Order Aberrations After Blinking. Eye Contact Lens 2008; 34:100-5. [DOI: 10.1097/icl.0b013e31812e008b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Visual acuity with spherical and toric soft contact lenses in low- to moderate-astigmatic eyes. Optom Vis Sci 2008; 84:969-75. [PMID: 18049362 DOI: 10.1097/opx.0b013e318157c6dc] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To evaluate the visual acuity of myopic, astigmatic eyes, with spherical and toric soft contact lenses. METHODS A randomized, masked, cross-over study was conducted to compare acuity with soft spherical and toric contact lenses on patients with between -0.75 and -2.00 D of refractive astigmatism. A total of 15 patients (30 eyes) were fitted with four brands of spherical and toric lenses (Acuvue Advance, Biomedics 55, Frequency 55, and SofLens 66), in random order. An initial visit was conducted to fit the lenses and an over-refraction (OR) was performed to determine the best prescription. At the measurement visit, patients' pupils were dilated with 1.0% tropicamide and 2.5% phenylephrine to allow wavefront aberration measurements, and a final OR was performed. A 6-mm aperture was held in front of the eye to measure visual acuity through just the contact lens and the contact lens with the final OR. Acuity was measured monocularly, under photopic and mesopic conditions with high- and low-contrast logMAR charts at distance. Differences in acuity were analyzed using repeated measures analysis of variance. RESULTS Visual acuity with soft spherical contact lenses was not significantly different between lens brands. For toric contact lenses, acuity was significantly better with Biomedics 55 and SofLens 66 than with Acuvue Advance; and acuity with SofLens 66 was significantly better than with Frequency 55. Low-astigmatic eyes gained between 3 and 5.5 letters of acuity with toric contact lenses vs. spherical lenses; and moderate-astigmatic eyes gained between 8 and 12.5 letters. CONCLUSIONS Both low- and moderate-astigmatic eyes showed improvements in acuity with toric contact lenses. Lens brand had a measurable effect on acuity for toric contact lenses. Further investigation of aberrations induced by contact lens design is warranted to explain the observed differences in visual performance.
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Effect of higher-order aberrations on visual function in keratoconic eyes with a rigid gas permeable contact lens. Am J Ophthalmol 2007; 144:924-929. [PMID: 17949670 DOI: 10.1016/j.ajo.2007.08.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 07/29/2007] [Accepted: 08/07/2007] [Indexed: 11/24/2022]
Abstract
PURPOSE To study the effect of higher-order aberrations (HOAs) on visual function in keratoconus with a rigid gas permeable (RGP) contact lens (CLs). DESIGN Retrospective nonrandomized study. METHODS Thirteen eyes of 10 subjects with keratoconus who wore a RGP CLs (KC-RGP group), 15 eyes of nine normal subjects (normal group), and 14 eyes of nine subjects who wore a RGP CLs (RGP group) who had no ocular diseases except for refractive errors and had 20/20 or better-corrected visual acuity were included in this study. The root-mean-square (RMS) of the third-, fourth-, fifth-, and sixth-order Zernike coefficients (total HOAs), the RMS of the third-order Zernike coefficients (S3) (coma-like aberration), the RMS of the fourth-order coefficients (S4) (spherical-like aberrations), and the area under the log contrast sensitivity function (AULCSF) were evaluated. RESULTS The AULCSF in the KC-RGP group was significantly lower than in the other two groups. The total HOAs, S3, and S4 in the KC-RGP group were significantly higher than in the other two groups. There were significant negative correlations between the area under the log contrast sensitivity function and the total HOAs, S3, and S4. CONCLUSIONS The visual performance in a keratoconic eye with a RGP CLs degrades compared with normal eyes with and without RGP CLs, even if the corrected VA is good. The degradation is assumed to be related to residual HOAs in a keratoconic eye with a RGP CLs.
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Marsack JD, Parker KE, Pesudovs K, Donnelly WJ, Applegate RA. Uncorrected wavefront error and visual performance during RGP wear in keratoconus. Optom Vis Sci 2007; 84:463-70. [PMID: 17568315 DOI: 10.1097/opx.0b013e31802e64f0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To examine the relationship between uncorrected residual wavefront error and visual performance (VP) in rigid gas permeable (RGP) contact lens-wearing keratoconic eyes. METHODS Seven eyes from six subjects (six moderate, one severe) were studied (mean +/- SD age: 42.71 +/- 11.38 years). Significant corneal scarring was an exclusion criterion. Measurements were taken with RGP lenses in place. After pupil dilation, the VP measures of high contrast logMAR visual acuity (VA) and Pelli-Robson contrast sensitivity (PRCS) were measured through a 5-mm artificial pupil. Wavefront error was measured using a Shack-Hartmann wavefront sensor and calculated over 5 mm. For both VP and wavefront error, comparisons were made to previously collected normal values by calculating the interval encompassing 95% of normals, then reporting how many of the seven keratoconic eyes fell outside the normal interval. Additionally, second to sixth order aberrations were processed into four previously reported image quality metrics: root mean square of the wavefront (RMSw), root mean square of the slope (RMSs), average blur strength (Bave) and diameter containing 50% light energy (D50) and regressed against VP measures. RESULTS Five of seven keratoconic eyes fell outside the normal interval (-0.23 to 0.09) for VA and two of seven fell outside the normal interval (1.59 to 2.03) for PRCS. Five of seven keratoconic eyes fell outside the normal interval (0.07 to 0.35 microm) for total higher order RMS. Linear regressions demonstrated relationships between both VA and PRCS and the image quality metrics RMSw, D50, RMSs, and Bave with R values for VA = 0.30, 0.30, 0.47, 0.62, and PRCS = 0.21, 0.15, 0.45, 0.75 respectively. CONCLUSIONS VP in RGP-wearing keratoconic eyes is reduced and higher order wavefront aberrations are elevated compared to normals. Metrics of retinal image quality demonstrate a relationship between keratoconic VP and residual wavefront aberrations. This relationship suggests developing corrections that more completely correct aberrations may improve visual performance in keratoconus.
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Affiliation(s)
- Jason D Marsack
- Visual Optics Institute, College of Optometry, University of Houston, Houston, TX 77204, USA.
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Abstract
PURPOSE The purpose of this study is to contrast the clinical and vision-related quality of life outcomes between Synergeyes, a hybrid contact lens, and Bausch & Lomb Soflens 66 Toric contact lenses in a cross-over design. Also, to determine subject preference of one mode of lens wear over the other. METHODS The Synergeyes lens has a central rigid gas permeable portion made of Paragon HDS100 material (paflufocon D) bonded to the nonionic hydrophilic skirt material of 27% water (PolyHEMA hem-iberfilcon A). The Soflens 66 Toric lens is made of a nonionic hydrophilic 66% water (alphafilcon A) material. Subjects age 18 years and older with spherical refractive error between -0.50 and -8.00 D and astigmatism correction of -0.75 to -3.50 D were randomly assigned to wear one mode of contact lens for 1 month then wear the alternate mode for 1 month. Follow-up visits were done at 1 and 4 weeks. Data gathered at these visits included high-contrast log MAR distance visual acuity, average wearing time, comfortable wearing time, over-refraction, and slit lamp observations for corneal edema, conjunctival hyperemia, and corneal staining. At each visit, subjects were asked to rate overall comfort, dryness, and comfortable wearing time. Subjects were asked to complete the NEI-RQL-42 questionnaire at the end of each lens wearing period. Upon completion of both lens wearing modes, subjects were asked to choose their preferred mode. RESULTS Fifty subjects completed the study; 22 (44%) preferred the Synergeyes lenses, and 28 (56%) preferred the Soflens 66 Toric soft lenses. Measured visual acuity was significantly better with the Synergeyes lenses. Of the 13 attributes analyzed in the RQL-42, a statistically significant difference between the two modes was found in only one category, "symptoms." In that category, subjects indicated fewer symptoms when wearing soft lenses. The subjects' ratings also showed significantly more comfort while wearing the soft toric lenses. CONCLUSIONS Bausch & Lomb Soflens 66 Toric lenses were more comfortable and were perceived to produce less symptoms of dryness, itchiness, and lens awareness than Synergeyes lenses. Synergeyes lenses gave better visual acuity than the soft toric lenses.
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Affiliation(s)
- Michael J Lipson
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA.
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Pantanelli S, MacRae S, Jeong TM, Yoon G. Characterizing the wave aberration in eyes with keratoconus or penetrating keratoplasty using a high-dynamic range wavefront sensor. Ophthalmology 2007; 114:2013-21. [PMID: 17553566 DOI: 10.1016/j.ophtha.2007.01.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2005] [Revised: 01/07/2007] [Accepted: 01/08/2007] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to characterize aberrations in 2 populations of eyes, namely those with keratoconus (KC) and those having undergone penetrating keratoplasty (PK), using a large-dynamic range Shack-Hartmann wavefront sensor. DESIGN Prospective comparative case series. PARTICIPANTS Twenty-one people with ocular pathologic features (either KC or PK) were recruited for this study. A previously compiled population of 190 people with no pathologic features other than refractive error was used as a means for comparison. METHODS Thirty-three abnormal eyes (19 with KC and 14 PK) were measured using a high-dynamic range wavefront sensor, and Zernike coefficients were computed over a 6-mm pupil. The data then were used to characterize the populations by themselves, as well as to compare them with the population of normal eyes. MAIN OUTCOME MEASURES Root mean square (RMS) higher-order aberration (HOA), percent of higher-order or total aberration variance, and magnitude of individual Zernike modes (in micrometers). Visual benefit of correcting higher-order aberrations was used when comparing pathologic and normal populations. RESULTS The keratoconic eyes exhibited 2.24 microm of HOA RMS on average. Vertical coma accounted for 53+/-32% (mean+/-standard deviation [SD]) of the HOA variance and was the most dominant higher-order aberration. The PK subjects had an average higher-order RMS of 2.25 microm, and trefoil dominated in this population with an average HOA variance contribution of 38+/-23% (mean+/-SD). The KC and PK higher-order aberrations represented 16+/-20% and 16+/-13% (mean+/-SD) of the total aberration variance, whereas the ratio was only 1+/-1% in the normal population. A visual benefit calculation on 15 KC eyes and 14 PK eyes yielded a result of 4.4+/-2.0 and 6.0+/-1.5 (mean+/-SD), respectively, whereas the normal population had a visual benefit of only 2.1+/-0.4. CONCLUSIONS Eyes with KC and PK have higher-order aberrations that are approximately 5.5 times more than what is typical in normal eyes. Vertical coma is the dominant higher-order aberration in people with KC, whereas PK eyes are dominated by trefoil, spherical aberration, and coma. Correcting these aberrations may provide substantial improvements in vision beyond what is possible with conventional correction methods.
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Affiliation(s)
- Seth Pantanelli
- Department of Biomedical Engineering, Center for Visual Science, University of Rochester, Rochester, New York 14627, USA.
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Abstract
PURPOSE To provide a summary of the methods used by clinical wavefront analyzers and their historical, current, and future applications. METHODS Review of the literature and authors' experience with the various devices. RESULTS A wide range of clinical wavefront aberrometers, which use different principles, are available to clinicians and researchers. CONCLUSIONS Applications of wavefront analyzers in vision sciences range from assessment of refractive error, refractive surgery planning, evaluation of outcomes, optimization of contact lenses and IOL designs, evaluation of pathology relating to optical performance of the eye, and evaluation of accommodation alterations.
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Affiliation(s)
- Alejandro Cerviño
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
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