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Nagra M, Patel M, Barbur J. Changes in forward light scatter parameters as a function of refractive error in young adults. Graefes Arch Clin Exp Ophthalmol 2020; 258:925-930. [PMID: 31912219 PMCID: PMC7575508 DOI: 10.1007/s00417-019-04584-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 11/04/2022] Open
Abstract
Background/aims Some aspects of visual performance worsen with increasing myopia. Whilst the underlying causes are not always clear, reduction in retinal image quality is often attributed to structural changes in the posterior myopic eye. Forward light scatter, originating principally from the cornea and lens, is known to produce veiling glare which subsequently reduces retinal image contrast. It is therefore of interest to investigate whether forward light scatter varies with refractive error. Methods Thirteen young-adult subjects (18–25 years), with mean spherical errors (MSE ± sd, D) RE, − 1.69 ± 2.02 (range 0.38 to − 4.75); LE, − 1.91 ± 1.94 (range 0.50 to − 4.63) underwent binocular assessment of forward light scatter using the AVOT light scatter test. Five glare annuli, with effective eccentricities ranging from 2 to 10°, were used to estimate parameters, k and n, which define the light scatter function of the eye. These were then used to calculate the area under the light scatter function (k′) and the total volume of light scatter (k″). Results Significant correlation was found between increasing myopia and k′ values (RE, p < 0.05; r = 0.64; LE, p < 0.05, r = 0.66). Neither the ‘volume’ of light scatter (k″), the parameter, n, which controls the angular distribution of light scatter, or the straylight parameter constant, k, were significantly correlated with refractive error (p > 0.05 for both eyes). Axial length was also not correlated with any of the light scatter parameters measured. Conclusion The preliminary data from this study provide evidence that some light scatter parameters may be correlated with refractive error. Further studies are needed to characterize how changes in the anterior media of the eye, and inclusion of a wider range of refractive errors, may affect forward light scatter.
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Affiliation(s)
- Manbir Nagra
- School of Health and Care Professions, University of Portsmouth, Portsmouth, PO1 2DT, UK.
| | - Mansi Patel
- Applied Vision Research Centre, Division of Optometry and Visual Science, City, University of London, London, EC1V 0HB, UK
| | - John Barbur
- Applied Vision Research Centre, Division of Optometry and Visual Science, City, University of London, London, EC1V 0HB, UK
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Iijima A, Shimizu K, Yamagishi M, Kobashi H, Igarashi A, Kamiya K. Assessment of subjective intraocular forward scattering and quality of vision after posterior chamber phakic intraocular lens with a central hole (Hole ICL) implantation. Acta Ophthalmol 2016; 94:e716-e720. [PMID: 27288153 DOI: 10.1111/aos.13092] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/17/2016] [Indexed: 01/22/2023]
Abstract
PURPOSE To evaluate the subjective intraocular forward scattering and quality of vision after posterior chamber phakic intraocular lens with a central hole (Hole ICL, STAAR Surgical) implantation. METHODS We prospectively examined 29 eyes of 29 consecutive patients (15 men and 14 women; ages, 37.2 ± 8.8 years) undergoing Hole ICL implantation. We assessed the values of the logarithmic straylight value [log (s)] using a straylight meter (C-Quant™ , Oculus) preoperatively and 3 months postoperatively. The patients completed a questionnaire detailing symptoms on a quantitative grading scale (National Eye Institute Refractive Error Quality of Life Instrument-42; NEI RQL-42) 3 months postoperatively. We compared the preoperative and postoperative values of the log(s) and evaluated the correlation of these values with patient subjective symptoms. RESULTS The mean log(s) was not significantly changed, from 1.07 ± 0.20 preoperatively, to 1.06 ± 0.17 postoperatively (Wilcoxon signed-rank test, p = 0.641). There was a significant correlation between the preoperative and postoperative log(s) (Spearman's correlation coefficient r = 0.695, p < 0.001). The postoperative log(s) was significantly associated with the scores of glare in the questionnaire (Spearman's correlation coefficient r = -0.575, p = 0.017). CONCLUSIONS According to our experience, Hole ICL implantation does not induce a significant additional change in the subjective intraocular forward scattering. The symptom of glare after Hole ICL implantation was significantly correlated with the postoperative intraocular forward scattering in relation to the preoperative one.
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Affiliation(s)
- Ayaka Iijima
- Department of Ophthalmology; University of Kitasato School of Medicine; Kanagawa Japan
| | - Kimiya Shimizu
- Department of Ophthalmology; University of Kitasato School of Medicine; Kanagawa Japan
| | - Mayumi Yamagishi
- Department of Ophthalmology; University of Kitasato School of Medicine; Kanagawa Japan
| | - Hidenaga Kobashi
- Department of Ophthalmology; University of Kitasato School of Medicine; Kanagawa Japan
| | - Akihito Igarashi
- Department of Ophthalmology; University of Kitasato School of Medicine; Kanagawa Japan
| | - Kazutaka Kamiya
- Department of Ophthalmology; University of Kitasato School of Medicine; Kanagawa Japan
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Patterson EJ, Bargary G, Barbur JL. Understanding disability glare: light scatter and retinal illuminance as predictors of sensitivity to contrast. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2015; 32:576-85. [PMID: 26366766 DOI: 10.1364/josaa.32.000576] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The presence of a bright light in the visual field has two main effects on the retinal image: reduced contrast and increased retinal illuminance because of scattered light; the latter can, under some conditions, lead to an improvement in retinal sensitivity. The combined effect remains poorly understood, particularly at low light levels. A psychophysical flicker-cancellation test was used to measure the amount and angular distribution of scattered light in the eye for 40 observers. Contrast thresholds were measured using a functional contrast sensitivity test. Pupil-plane glare-source illuminances (i.e., 0, 1.35, and 19.21 lm/m2), eccentricities (5°, 10°, and 15°), and background luminances (1, 2.6, and 26 cd/m2) were investigated. Visual performance was better than predicted, based on a loss of retinal image contrast caused by scattered light, particularly in the mesopic range. Prediction accuracy improved significantly when the expected increase in retinal sensitivity in the presence of scattered light was also incorporated in the model.
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van den Berg TJTP, Franssen L, Kruijt B, Coppens JE. History of ocular straylight measurement: A review. Z Med Phys 2012. [PMID: 23182462 DOI: 10.1016/j.zemedi.2012.10.009] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The earliest studies on 'disability glare' date from the early 20(th) century. The condition was defined as the negative effect on visual function of a bright light located at some distance in the visual field. It was found that for larger angles (>1 degree) the functional effect corresponded precisely to the effect of a light with a luminosity equal to that of the light that is perceived spreading around such a bright source. This perceived spreading of light was called straylight and by international standard disability glare was defined as identical to straylight. The phenomenon was recognized in the ophthalmological community as an important aspect of the quality of vision and attempts were made to design instruments to measure it. This must not be confused with instruments that assess light spreading over small distances (<1 degree), as originating from (higher order) aberrations and defocus. In recent years a new instrument has gained acceptance (C-Quant) for objective and controllable assessment of straylight in the clinical setting. This overview provides a sketch of the historical development of straylight measurement, as well as the results of studies on the origins of straylight (or disability glare) in the normal eye, and on findings on cataract (surgery) and corneal conditions.
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Affiliation(s)
- Thomas J T P van den Berg
- Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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van Bree MC, van Verre HP, Devreese MT, Larminier F, van den Berg TJ. Straylight Values after Refractive Surgery: Screening for Ocular Fitness in Demanding Professions. Ophthalmology 2011; 118:945-53. [DOI: 10.1016/j.ophtha.2010.09.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 09/14/2010] [Accepted: 09/16/2010] [Indexed: 11/26/2022] Open
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Straylight measurements in laser in situ keratomileusis and laser-assisted subepithelial keratectomy for myopia. J Cataract Refract Surg 2010; 36:465-71. [DOI: 10.1016/j.jcrs.2009.10.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 08/21/2009] [Accepted: 10/15/2009] [Indexed: 11/18/2022]
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García-Lázaro S, Ferrer-Blasco T, Ortí-Navarro S, Cerviño A, Montés-Micó R. Relevance of pupil size in the clinical determination of retinal straylight on young healthy human eyes. Graefes Arch Clin Exp Ophthalmol 2009; 248:395-9. [DOI: 10.1007/s00417-009-1258-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 10/13/2009] [Accepted: 11/19/2009] [Indexed: 10/20/2022] Open
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Retinal Straylight and Complaint Scores 18 Months After Implantation of the AcrySof Monofocal and ReSTOR Diffractive Intraocular Lenses. J Refract Surg 2009; 25:485-92. [DOI: 10.3928/1081597x-20090512-02] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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de Vries NE, Franssen L, Webers CA, Tahzib NG, Cheng YY, Hendrikse F, Tjia KF, van den Berg TJ, Nuijts RM. Intraocular straylight after implantation of the multifocal AcrySof ReSTOR SA60D3 diffractive intraocular lens. J Cataract Refract Surg 2008; 34:957-62. [DOI: 10.1016/j.jcrs.2008.02.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 02/20/2008] [Indexed: 10/22/2022]
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Cerviño A, Gonzalez-Meijome JM, Linhares JMM, Hosking SL, Montes-Mico R. Effect of sport-tinted contact lenses for contrast enhancement on retinal straylight measurements. Ophthalmic Physiol Opt 2008; 28:151-6. [DOI: 10.1111/j.1475-1313.2008.00541.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cerviño A, Hosking SL, Montés-Micó R, Alió JL. Retinal straylight in patients with monofocal and multifocal intraocular lenses. J Cataract Refract Surg 2008; 34:441-6. [DOI: 10.1016/j.jcrs.2007.11.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Accepted: 11/02/2007] [Indexed: 11/16/2022]
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Aslam TM, Haider D, Murray IJ. Principles of disability glare measurement: an ophthalmological perspective. ACTA ACUST UNITED AC 2007; 85:354-60. [PMID: 17313443 DOI: 10.1111/j.1600-0420.2006.00860.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Disability glare describes the loss of retinal image contrast as a result of intraocular light scatter, or straylight. It has increasingly important modern implications such as with cataract and refractive surgery or high-intensity lighting. However, its measurement has proven difficult despite many varying approaches. This article aims to explain the principles and problems associated with glare testing that are important for assessment and use of glare measures. After defining disability glare, this article discusses the importance of its measurement to current clinical practice. It explains the principles and mechanisms that underlie disability glare and its measurement. Finally, some examples of available glare tests are described to illustrate the principles discussed.
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van Rijn LJ, Nischler C, Gamer D, Franssen L, de Wit G, Kaper R, Vonhoff D, Grabner G, Wilhelm H, Völker-Dieben HJ, van den Berg TJTP. Measurement of stray light and glare: comparison of Nyktotest, Mesotest, stray light meter, and computer implemented stray light meter. Br J Ophthalmol 2005; 89:345-51. [PMID: 15722317 PMCID: PMC1772572 DOI: 10.1136/bjo.2004.044990] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM To evaluate the properties of devices for measuring stray light and glare: the Nyktotest, Mesotest, "conventional" stray light meter and a new, computer implemented version of the stray light meter. METHODS 112 subjects, divided in three groups: (1) young subjects without any eye disease; (2) elderly subjects without any eye disease, and (3) subjects with (early) cataract in at least one eye. All subjects underwent a battery of glare and stray light tests, measurement of visual acuity, contrast sensitivity, refraction, and LOCS III cataract classification. Subjects answered a questionnaire on perceived disability during driving. RESULTS Repeatability values were similar for all glare/stray light tests. Validity (correlation with LOCS III and questionnaire scores), discriminative ability (ability to discriminate between the three groups), and added value (to measurement of visual acuity and contrast sensitivity) were all superior for both stray light meters. Results of successive measurements are interrelated for the conventional but not the new stray light meter. This indicates a better resistance to fraud for the latter device. CONCLUSIONS The new computer implemented stray light meter is the most promising device for future stray light measurements.
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Affiliation(s)
- L J van Rijn
- Ophthalmology, Vrije Universiteit Medical Centre, PO Box 7057, NL-1007 MB Amsterdam, Netherlands.
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Dennis RJ, Beer JMA, Baldwin JB, Ivan DJ, Lorusso FJ, Thompson WT. Using the Freiburg Acuity and Contrast Test to measure visual performance in USAF personnel after PRK. Optom Vis Sci 2004; 81:516-24. [PMID: 15252351 DOI: 10.1097/00006324-200407000-00013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Photorefractive keratectomy (PRK) may be an alternative to spectacle and contact lens wear for United States Air Force (USAF) aircrew and may offer some distinct advantages in operational situations. However, any residual corneal haze or scar formation from PRK could exacerbate the disabling effects of a bright glare source on a complex visual task. The USAF recently completed a longitudinal clinical evaluation of the long-term effects of PRK on visual performance, including the experiment described herein. METHODS After baseline data were collected, 20 nonflying active duty USAF personnel underwent PRK. Visual performance was then measured at 6, 12, and 24 months after PRK. Visual acuity (VA) and contrast sensitivity (CS) data were collected by using the Freiburg Acuity and Contrast Test (FrACT), with the subject viewing half of the runs through a polycarbonate windscreen. Experimental runs were completed under 3 glare conditions: no glare source and with either a broadband or a green laser (532-nm) glare annulus (luminance approximately 6090 cd/m) surrounding the Landolt C stimulus. RESULTS Systematic effects of PRK on VA relative to baseline were not identified. However, VA was almost 2 full Snellen lines worse with the laser glare source in place versus the broadband glare source. A significant drop-off was observed in CS performance after PRK under conditions of no glare and broadband glare; this was the case both with and without the windscreen. As with VA, laser glare disrupted CS performance significantly and more than broadband glare did. CONCLUSIONS PRK does not appear to have affected VA, but the changes in CS might represent a true decline in visual performance. The greater disruptive effects from laser versus broadband glare may be a result of increased masking from coherent spatial noise (speckle) surrounding the laser stimulus.
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Freedman KA, Brown SM, Mathews SM, Young RSL. Pupil size and the ablation zone in laser refractive surgery: Considerations based on geometric optics. J Cataract Refract Surg 2003; 29:1924-31. [PMID: 14604712 DOI: 10.1016/s0886-3350(03)00214-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE To determine whether the currently accepted method of selecting a minimum ablation zone size for refractive surgery based on dark-adapted pupil diameter is substantiated by geometric optical analysis. SETTING Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, Texas, USA. METHODS An optical model of the anterior segment was developed to calculate the effective corneal refractive diameter (ECRD), which is the diameter of the area of cornea that refracts all incident light rays arising from objects along the line of sight though the physical pupil (PP). The concept of the entrance pupil (EP) was reexamined and developed, and the ECRD was calculated over a range of corneal curvatures (K), anterior chamber depths (ACDs), and EP sizes. The model was generalized to include oblique light rays. Calculations were performed using MatLab Optimization Toolbox software (The MathWorks). RESULTS For a given EP size, the ECRD was significantly influenced by K and slightly influenced by ACD. CONCLUSIONS For objects on the line of sight, the ECRD was smaller than the EP in all cases. Regarding rays from objects in the periphery, the ECRD expanded rapidly as the angle of oblique incidence increased. For objects on the line of sight, the ECRD is always smaller than the clinically measured pupil (EP) because the EP is substantially magnified relative to the PP. Ablation zones larger than the EP should, in theory, prevent scattered or defocused light rays from contributing to the foveal image. When considering objects in the periphery, the increase in ECRD is sufficiently rapid that current refractive procedures cannot stop scattered light from these objects from contributing to the retinal image.
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Affiliation(s)
- Kenn A Freedman
- Department of Ophthalmology and Visual Sciences, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
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Fan-Paul NI, Li J, Miller JS, Florakis GJ. Night vision disturbances after corneal refractive surgery. Surv Ophthalmol 2002; 47:533-46. [PMID: 12504738 DOI: 10.1016/s0039-6257(02)00350-8] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A certain percentage of patients complain of "glare" at night after undergoing a refractive surgical procedure. When patients speak of glare they are, technically, describing a decrease in quality of vision secondary to glare disability, decreased contrast sensitivity, and image degradations, or more succinctly, "night vision disturbances." The definitions, differences, and methods of measurement of such vision disturbances after refractive surgery are described in our article. In most cases of corneal refractive surgery, there is a significant increase in vision disturbances immediately following the procedure. The majority of patients improve between 6 months to 1 year post-surgery. The relation between pupil size and the optical clear zone are most important in minimizing these disturbances in RK. In PRK and LASIK, pupil size and the ablation diameter size and location are the major factors involved. Treatment options for disabling glare are also discussed. With the exponential increase of patients having refractive surgery, the increase of patients complaining of scotopic or mesopic vision disturbances may become a major public health issue in the near future. Currently, however, there are no gold-standard clinical tests available to measure glare disability, contrast sensitivity, or image degradations. Standardization is essential for objective measurement and follow-up to further our understanding of the effects of these surgeries on the optical system and thus, hopefully, allow for modification of our techniques to decrease or eliminate post-refractive vision disturbances.
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Affiliation(s)
- Nancy I Fan-Paul
- Edward S. Harkness Eye Institute, Columbia Presbyterian Medical Center, 635 West 165th Street, New York, NY 10032, USA
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Schallhorn SC, Blanton CL, Kaupp SE, Sutphin J, Gordon M, Goforth H, Butler FK. Preliminary results of photorefractive keratectomy in active-duty United States Navy personnel. Ophthalmology 1996; 103:5-22. [PMID: 8628560 DOI: 10.1016/s0161-6420(96)30733-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PURPOSE To evaluate the safety, efficacy, and quality of vision after photorefractive keratectomy (PRK) in active-duty military personnel. METHODS Photorefractive keratectomy (6.0-mm ablation zone) was performed on 30 navy/marine personnel(-2.00 to -5.50 diopters [D]; mean, -3.35 D). Glare disability was assessed with a patient questionnaire and measurements of intraocular light scatter and near contrast acuity with glare. RESULTS At 1 year, all 30 patients had 20/20 or better uncorrected visual acuity with no loss of best-corrected vision. By cycloplegic refraction, 53% (16/30) of patients were within +/- 0.50 D of emmetropia and 87% (26/30) were within +/- 1.00 D. The refraction (mean +/- standard deviation) was +0.45 +/- 0.56 D (range, -1.00 to 1.63 D). Four patients (13%) had an overcorrection of more than 1 D. Glare testing in the early (1 month) postoperative period demonstrated increased intraocular light scatter (P<0.01) and reduced contrast acuity (with and without glare, (P<0.01). These glare measurements statistically returned to preoperative levels by 3 months (undilated) and 12 months (dilated) postoperatively. Two patients reported moderate to severe visual symptoms (glare, halo, night vision) worsened by PRK. One patient had a decrease in the quality of night vision severe enough to decline treatment in the fellow eye. Intraocular light scatter was increased significantly (>2S D) in this patient after the procedure. CONCLUSIONS Photorefractive keratectomy reduced myopia and improved the uncorrected vision acuity of all patients in this study. Refinement of the ablation algorithm is needed to decrease the incidence of hyperopia. Glare disability appears to be a transient event after PRK. However, a prolonged reduction in the quality of vision at night was observed in one patient and requires further study.
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Affiliation(s)
- S C Schallhorn
- Department of Ophthalomology and Clinical Investigation, Naval Medical Center, San Diego, CA, USA
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Burillon C, Guigon B, Durand L. Oblique Versus Vertical-Horizontal Incision Orientation in Four-Incision Radial Keratotomy. J Refract Surg 1995; 11:453-9. [PMID: 8624829 DOI: 10.3928/1081-597x-19951101-11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Four-incision radial keratotomy is used for the correction of mild to moderate myopia. The traditional orientation of incisions was naturally on the horizontal and vertical meridians. We undertook a comparative study of oblique versus traditional four-incision radial keratotomy (orthogonal orientation) to show the advantage of an oblique incision orientation. METHODS A prospective study of two groups of 21 eyes was conducted: an orthogonal group with vertical-horizontal orientation of the four incisions, and an oblique group with four obliquely oriented incisions. Spatial contrast sensitivity, glare, and night vision tests were performed and results compared. The follow up period was 3 months. RESULTS Glare and contrast sensitivity were less affected with oblique orientation of incisions. There was no significant difference regarding night vision effects. We observed a decrease in induced astigmatism with oblique orientation. CONCLUSION The location of horizontal incisions within the palpebral fissure and the unequal lengths of horizontal and vertical incisions are responsible for ocular alterations. An oblique orientation is preferable to avoid glare, starburst, and induced astigmatism.
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Affiliation(s)
- C Burillon
- Clinique Ophtalmologique A, Hôpital Edouard Herriot, Lyon, France
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Veraart HG, van den Berg TJ, Hennekes R, Adank AM. Stray light in photorefractive keratectomy for myopia. Doc Ophthalmol 1995; 90:35-42. [PMID: 8549241 DOI: 10.1007/bf01203292] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We performed a study to evaluate the influence on visual function of intraocular straylight after photorefractive keratectomy (PRK). We present 4 eyes of 4 myopic individuals, who had contacted our clinic for keratorefractive surgical treatment. PRK's were performed with a Summit laser, using a 5 mm ablation zone. The straylight meter was used to measure the amount of intraocular scattered light, the physical cause of glare complaints, before and after PRK. This apparatus uses the direct compensation method to assess the amount of intraocular light scatter. The results showed a significant increase in straylight values, in the tested eyes, during the first two weeks after PRK. After the initial rise, straylight values returned to preoperative levels, except for two eyes that clearly developed a haze higher than grade two. Instead of returning to baseline levels, straylight values remained significantly higher in these eyes.
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Affiliation(s)
- H G Veraart
- Department of Ophthalmology, Free University of Brussels, Belgium
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Landesz M, Worst JG, Siertsema JV, van Rij G. Correction of High Myopia With the Worst Myopia Claw Intraocular Lens. J Refract Surg 1995; 11:16-25. [PMID: 7641044 DOI: 10.3928/1081-597x-19950101-07] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Phakic anterior chamber lenses is one of the modalities used to correct high myopia. We report the initial results of our prospective study on the Worst myopia claw intraocular lens (IOL) that is fixated to the anterior iris. METHODS We studied 35 eyes in 18 patients with a preoperative myopia ranging from -6.00 to -28.00 diopters (D). The follow up ranged from 6 months (n = 15) to 12 months (n = 20). RESULTS In 26 (74.3%) eyes, the postoperative spherical equivalent refractive error was within 1.00 D of emmetropia. The mean refraction was stable between 1 to 2 months and 12 months. The mean spectacle-corrected visual acuity improved from 20/50 to 20/40. The straylight measurements did not show a significant increase postoperatively (p = .64). The mean endothelial cell loss was 5.6% (range, +6.3% to -22.6%) at 6 months, and 8.9% (range, +0.77% to -23.5%) at 12 months. We did not encounter major complications. CONCLUSION Implanting a Worst myopia claw IOL in high myopic eyes resulted in a stable, reasonably accurate refractive outcome. This group of patients will be followed longer because of concern over ocular complications with this technique.
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Affiliation(s)
- M Landesz
- Department of Ophthalmology, University Hospital, Groningen, The Netherlands
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Butuner Z, Elliott DB, Gimbel HV, Slimmon S. Visual Function One Year After Excimer Laser Photorefractive Keratectomy. J Refract Surg 1994. [DOI: 10.3928/1081-597x-19941101-07] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Binder PS. Radial Keratotomy and Excimer Laser Photorefractive Keratectomy for the Correction of Myopia. J Refract Surg 1994. [DOI: 10.3928/1081-597x-19940701-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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