Straylight before and after LASEK in Myopia: Changes in Retinal Straylight (original) (raw)
Related papers
Journal of Refractive Surgery, 2010
To compare intraocular straylight and contrast sensitivity determined before and 15 days and 6 months after laser keratomileusis. Methods: A single-centre, prospective, longitudinal randomized trial was performed on 20 subjects undergoing refractive surgery. In each subject, best spectacle-corrected visual acuity (BSCVA) and straylight and contrast sensitivity were determined preoperatively (on the day of refractive surgery) and then after laser in situ keratomileusis (LASIK) surgery in the 15-day and 6-month follow-up visits. Straylight was measured using the van den Berg straylight meter (third generation). Contrast sensitivity was determined under photopic and mesopic conditions using the VCTS 6500 (Vision Contrast Test System). BSCVA was measured using Early Treatment Diabetic Retinopathy Study charts (LogMAR units). All measurements were obtained over time and compared. Results: Straylight values (mean Ϯ SD) were 0.99 Ϯ 0.03, 0.88 Ϯ 0.03, and 0.93 Ϯ 0.03 before and 1/2 and 6 months after LASIK surgery. These values significantly fell from preoperative levels to those recorded 15 days after LASIK (P ϭ 0.03) although values at 6 months failed to differ from baseline (PϾ0.05). Photopic and mesopic contrast sensitivity measured at several spatial frequencies remained stable. No correlations between contrast sensitivity or BSCVA and intraocular straylight were observed 15 days and 6 months after LASIK. Conclusions: Intraocular straylight was reduced 15 days after surgery although by 6 months values returned to preoperative levels. These changes in straylight values could not be related to changes in mesopic and photopic contrast sensitivity or BSCVA during the follow-up period.
Intraocular straylight and contrast sensitivity after LASIK
Acta Ophthalmologica Scandinavica, 2007
To compare intraocular straylight and contrast sensitivity determined before and 15 days and 6 months after laser keratomileusis. Methods: A single-centre, prospective, longitudinal randomized trial was performed on 20 subjects undergoing refractive surgery. In each subject, best spectacle-corrected visual acuity (BSCVA) and straylight and contrast sensitivity were determined preoperatively (on the day of refractive surgery) and then after laser in situ keratomileusis (LASIK) surgery in the 15-day and 6-month follow-up visits. Straylight was measured using the van den Berg straylight meter (third generation). Contrast sensitivity was determined under photopic and mesopic conditions using the VCTS 6500 (Vision Contrast Test System). BSCVA was measured using Early Treatment Diabetic Retinopathy Study charts (LogMAR units). All measurements were obtained over time and compared. Results: Straylight values (mean Ϯ SD) were 0.99 Ϯ 0.03, 0.88 Ϯ 0.03, and 0.93 Ϯ 0.03 before and 1/2 and 6 months after LASIK surgery. These values significantly fell from preoperative levels to those recorded 15 days after LASIK (P ϭ 0.03) although values at 6 months failed to differ from baseline (PϾ0.05). Photopic and mesopic contrast sensitivity measured at several spatial frequencies remained stable. No correlations between contrast sensitivity or BSCVA and intraocular straylight were observed 15 days and 6 months after LASIK. Conclusions: Intraocular straylight was reduced 15 days after surgery although by 6 months values returned to preoperative levels. These changes in straylight values could not be related to changes in mesopic and photopic contrast sensitivity or BSCVA during the follow-up period.
Cornea, 2012
Long-term quality of vision after Descemet stripping endothelial keratoplasty (DSEK) was evaluated and correlated with corneal characteristics and subjective complaints. methods Thirty-four eyes were examined; patients had a single visit 6 to 64 months after DSEK for Fuchs' dystrophy. Best-corrected distance acuity (BCDA) and straylight were analyzed. To better evaluate long-term postoperative BCDA changes, longitudinal data were used from earlier visits. Corneal thickness was measured with the Visante anterior segment Optical Coherence Tomography (OCT). Interface, stromal and endothelial haze were semi-quantitatively graded using the slitlamp. Vision-related quality of life was evaluated with the 39-item National Eye Institute Visual Function Questionnaire (NEI VFQ-39) and a straylight questionnaire. Correlation analysis comparing corneal characteristics with visual quality was performed. results Mean postoperative time was 1027 ± 453 days. Mean BCDA at this time was 0.33 ± 0.19 logMAR. BCDA remained stable with long-term postoperative follow-up. Straylight averaged 1.47 ± 0.19, on average 0.12 log units higher than normal values for age-related pseudophakic eyes (P < 0.001). BCDA correlated with corneal haze (r = 0.50), whereas straylight showed a non-significant association (P = 0.12). Neither BCDA nor straylight correlated with corneal thickness. Mean VFQ-39 score was 77/100, and mean score of the straylight questionnaire was 46/100. Conclusion Quality of vision after DSEK does not return to normal levels of age-matched pseudophakic eyes, with decreased BCDA and increased straylight. Questionnaire scores indicate mild (VFQ-39) to moderate (straylight) subjective visual impairment. Corneal thickness and haze do not offer an adequate explanation for the decreased visual quality.
Journal of Optometry, 2008
In vivo study of retinal straylight in a patient before and after penetrating keratoplasty (PKP). METHODS: Retinal straylight was measured in a 65-year-old man suffering from a post-herpetic corneal scar, both before and after PKP using the compensation comparison method (C-Quant straylight meter, Oculus GmbH, Germany). RESULTS: Retinal straylight values before surgery were high compared to those obtained for age-matched normals in previous studies, due to light scattering induced by the corneal scar. Mean and standard deviation straylight values before and 9 months after PKP were log(s)=1.71±0.09 and 1.05±0.08, respectively. Decrease in retinal straylight could be explained by an improved corneal transparency, resulting in a significant improvement in visual acuity. CONCLUSIONS: Retinal straylight measurement provides objective and clinically valuable information about forward light scattering as the cause of visual disability. Improvement of the visual function after surgery is underestimated by visual acuity measures.
Method for in vitro assessment of straylight from intraocular lenses
Biomedical Optics Express, 2015
Ocular straylight has been measured by means of psychophysical methods over the years. This approach gives a functional parameter yielding a straight comparison with optically defined light scattering, and the pointspread-function. This is of particular importance when the effect of intraocular lenses (IOLs) on postoperative straylight is sought. An optical system for straylight measurements of IOLs was adapted to a commercial device (C-Quant, Oculus), which employs such psychophysical method. The proposed modifications were validated using light-scattering filters and some sample IOLs. The measurements were performed by 3 observers to prove that results are independent from straylight of the eye. Other applications will be discussed.
Night Vision Disturbances After Corneal Refractive Surgery* 1
Survey of ophthalmology, 2002
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.