Multidisciplinary Ophthalmic Imaging
Optical Quality in Central Serous Chorioretinopathy Kyungmin Lee,1,2 Joonhong Sohn,2 Jong Gil Choi,2,3 and Sung Kun Chung1 1Department
of Ophthalmology and Visual Science, College of Medicine, Catholic University of Korea, Seoul, Korea Eye Hospital, Incheon, Korea 3 Department of Optometry, Seoul National University of Science and Technology, Seoul, Korea 2HanGil
Correspondence: Sung Kun Chung, Department of Ophthalmology and Visual Science, St. Paul’s Hospital, College of Medicine, Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701, Republic of Korea; [email protected]. Submitted: April 28, 2014 Accepted: November 5, 2014 Citation: Lee K, Sohn J, Choi JG, Chung SK. Optical quality in central serous chorioretinopathy. Invest Ophthalmol Vis Sci. 2014;55:8598–8603. DOI:10.1167/iovs.14-14679
PURPOSE. To assess optical quality and intraocular scattering using the Optical Quality Analysis System (OQAS) in central serous chorioretinopathy (CSC) and to determine the effects of retinal changes on optical quality. METHODS. This was a prospective, case-control study. Participants were 29 patients with diagnosis of CSC. The control group consisted of the patients’ unaffected eyes. Initial logMAR visual acuity, central macular thickness (by spectral domain optical coherence tomography), and optical quality parameters including modulation transfer function (MTF) cutoff frequency, Strehl (2-dimensional) ratio, and OQAS values at 100%, 20%, and 9% contrast levels were investigated. Objective scattering index (OSI) at 4.0-mm pupil size was assessed in both eyes by using the OQAS. After 3 months of treatment, which included observation and focal laser or injections of antivascular endothelial growth factor, every CSC-affected eye was followed. Main outcome measures were differences between clinical parameters of the CSC-affected eye and those of the control eye and changes in those parameters according to the clinical course of CSC over 3 months. RESULTS. In CSC-affected eyes, the MTF cutoff was significantly reduced (P ¼ 0.01), and OSI was significantly increased (P ¼ 0.03). As macular thickness decreased, OSI decreased but did not become normalized compared to the control eye, nor was it statistically significantly correlated with central macular thickness change. CONCLUSIONS. Retinal change affected optical quality and intraocular scatter. Therefore, when the severity of a cataract is assessed using the OQAS, retinal status should be considered when interpreting OQAS values. Keywords: central serous chorioretinopathy, double-pass system, optical quality, retinal sensitivity
ision can be assessed in terms of visual acuity and visual quality. Visual quality can be expressed as optical quality, composed of ocular scatter, aberration, and diffraction. In order to correct vision, it is important to evaluate not only visual acuity but also optical quality. Recently, different kinds of aberrometers have been developed to detect ocular aberrations.1,2 However, these instruments can only detect aberrations in transparent ocular medium, and they can sometimes underestimate optical quality because they do not assess parameters such as scatter. Furthermore, because in most of these systems the same route used for the inlet of the initial beam is also used as the outlet for detection, the aberrometers can overestimate aberrations. In order to solve these problems, the Optical Quality Analysis System (OQAS; Visiometrics, Terrassa, Spain) was developed.3 The OQAS uses a double-pass method whereby different routes are used for the inlet of the initial laser beam and the outlet of the detection mirror, thus preventing confusion between induction and detection beams. It is the only commercially available device that enables measurement of the effects of optical aberration and the effects of loss of ocular transparency on the optical quality of the human eye.3–5 OQAS detects retinal image quality by using a retinal point spread function, which is captured from the inner retinal surface. Numerous studies have shown that ocular quality is influenced by both aberration and
scattering. However, no studies have investigated the changes in or influences on ocular quality if the retina itself is not normal. Thus, we were curious as to whether OQAS values would remain unchanged in the presence of abnormal lesions in the retina without any other optical problems. Central serous chorioretinopathy (CSC) is a disorder characterized by serous retinal detachment and/or retinal pigment epithelium (RPE) detachment, with changes most often confined to the macula, and associated with leakage of fluid through the RPE into the subretinal space.6 It reportedly affects mostly men in their fourth to fifth decades, with most cases reported in patients from 45 to 51 years of age.7,8 Despite advances in imaging techniques and numerous studies of the disease, the pathophysiology of CSC remains poorly understood. Its clinical course is quite varied, but acute CSC is usually self-limiting in that visual acuity typically recovers within 1 to 3 months without visual sequelae, although recurrences are common.9–11 In this study, we assessed optical quality and intraocular scattering in acute CSC patients who were in either an active disease state or a resolved disease state by using the OQAS, with the aim of obtaining new reference data to assist clinical diagnosis. In addition, we analyzed the effects of retinal change on optical quality by means of objective parameters including modulation transfer function (MTF) cutoff frequency and Strehl
Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc. www.iovs.org j ISSN: 1552-5783
8598
V
IOVS j December 2014 j Vol. 55 j No. 12 j 8599
OQAS in Central Serous Chorioretinopathy ratio; OQAS values (OV) at contrast levels of 100%, 20%, and 9%; and objective scattering index (OSI).
TABLE 1. Demography and Baseline Characteristics Characteristic of CSC Patients
Value
METHODS
Total number of patients Ratio of males to females, % Age, y No. of patients with a history of smoking, % No. of patients with a history of steroid medication, %
29 23:6 (79%) 47.1 6 7.1
This prospective, nonrandomized, case-control study included patients who had an acute attack of CSC between August 2011 and February 2012, presenting at the HanGil Eye Hospital, Incheon, Korea. The study protocol followed guidelines of the Declaration of Helsinki and was approved by the relevant institutional review board and the Clinical Research Ethics Committee of HanGil Eye Hospital. All patients provided informed consent for participation in the study.
Inclusion and Exclusion Criteria Acute onset CSC was defined as CSC that was clinically evident after spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography (FAG), and dilated fundus examination, with symptoms having been present for less than 3 months. Exclusion criteria included a history of CSC in either eye; severe dry eye syndrome, defined as a tear break-up time of less than 5 seconds; clinically significant cataract presenting with a lens opacities classification system (LOCS) III grade of more than 3; retinal comorbidity such as diabetic retinopathy, retinal vein occlusion, or macular degeneration; and any other ocular comorbidity that might affect optical medium, such as corneal opacity or dystrophy. Patients with a history of amblyopia, hyperfluorescence on FAG in the contralateral eye, or more than 1 diopter (D) of astigmatism were also excluded. The experimental and control groups consisted of the CSC-affected eye and the unaffected eye (which did not show any change in the retina), respectively, of each patient. The endpoint of the study was 3 months after the treatment.
Patient Examination A complete ocular examination, SD-OCT, FAG, and OQAS assessment for a 4.0-mm pupil were performed at the initial visit and at 3 months after the treatment in both eyes. Visual acuity was evaluated with a Snellen chart and expressed as a fixed number. Central macular thickness was assessed by using SD-OCT (OPKO/OTI Ophthalmic Technologies, Inc., Toronto, ON, Canada). Thickness was double-checked by the retinal specialist (K. M. L.) manually to confirm the value from the report of SD-OCT. Spherical equivalent was calculated as ðspherical errorÞ þ ðcylinder errorÞ=2
ð1Þ
where each of these errors was evaluated by using an Auto RefKeratometer (RK-5, Canon, Inc., Tokyo, Japan). The optical quality parameters included objective refraction error, MTF cutoff frequency, Strehl ratio, OSI, and OV (at 100%, 20%, and 9% contrast, using the OQAS) for a 4.0-mm pupil. The manifest refractive error of the subjects was fully corrected during these measurements. Spherical error (up to 8 D) was automatically corrected by the double-pass system, and the residual spherical error (more than 8 D) and cylindrical error were corrected with an external lens because the uncorrected refractive error directly affects the optical outcome of the system.
Treatment of Acute CSC Treatment of acute CSC was dependent on patient status and demand. Observation was recommended for at least 1 month. After 1 month of observation, several options were recommended such as focal laser photocoagulation, intravitreal bevacizumab
13 (45%) 2 (7%)
Main symptom Central scotoma Metamorphopsia Micropsia Nonspecific
21 3 4 1
(72%) (10%) (14%) (4%)
OCT configuration SRF Combination of SRF and PED PED only
19 (66%) 9 (31%) 1 (3%)
Treatment Observation Focal laser Intravitreal anti-VEGF injection Failure of treatment
15 (52%) 10 (34%) 4 (14%) 3 (10%) 2 showed secondary CNV (þ) 1 showed unresolved SRF
CNV, choroidal neovascularization; PED, pigment epithelial detachment; SRF, subretinal fluid; VEGF, vascular endothelial growth factor.
injection, or further observation. All potential risks and benefits of each treatment were explained to the patients. Intravitreal injections of bevacizumab (Avastin, 25 mg/mL; Genentech, Inc., South San Francisco, CA, USA) were given after applying at least three drops of topical anesthetic (Alcaine; Alcon, Aliso Viejo, CA, USA). After disinfection and draping, a 0.05-mL volume containing 1.25 mg of bevacizumab was injected into the vitreous cavity, using a 30-gauge needle at a distance of 3.0 to 3.5 mm from the limbus, according to lens status. After the injection, a topical antimicrobial drug, levofloxacin ophthalmic solution (Cravit; Santen Pharmaceutical Co., Ltd., Osaka, Japan) was administered 4 times a day for a week. Focal laser photocoagulation was applied at the leaking point, which was detected by FAG. The Patterned Scanning Laser (PASCAL; OptiMedica Corp., Santa Clara, CA, USA) was used for treatment. Direct treatment of the leaking spot was conducted by using burns of 100 to 200 lm in diameter, unless the leak was immediately under the subfoveal area. Intensity and duration of the laser burns varied between 150 and 250 mW and 20 and 30 ms respectively.
Statistical Analysis Data are means 6 standard deviations. The Mann-Whitney U test was used for statistical comparisons between the CSCaffected group and the control group at the initial visit and between the CSC-affected group after 3 months of treatment and the control group at the initial visit. The Wilcoxon signed rank test was used to compare initial and posttreatment clinical data in the CSC-affected group. Spearman’s q correlation coefficient was used to evaluate the relationships between central macular thickness changes and changes in optical quality parameters in the CSC-affected group after treatment. Statistical analyses were performed using SPSS version 17.0 software (SPSS, Inc., Chicago, IL, USA), and P values of
Optical Quality in Central Serous Chorioretinopathy Kyungmin Lee,1,2 Joonhong Sohn,2 Jong Gil Choi,2,3 and Sung Kun Chung1 1Department
of Ophthalmology and Visual Science, College of Medicine, Catholic University of Korea, Seoul, Korea Eye Hospital, Incheon, Korea 3 Department of Optometry, Seoul National University of Science and Technology, Seoul, Korea 2HanGil
Correspondence: Sung Kun Chung, Department of Ophthalmology and Visual Science, St. Paul’s Hospital, College of Medicine, Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701, Republic of Korea; [email protected]. Submitted: April 28, 2014 Accepted: November 5, 2014 Citation: Lee K, Sohn J, Choi JG, Chung SK. Optical quality in central serous chorioretinopathy. Invest Ophthalmol Vis Sci. 2014;55:8598–8603. DOI:10.1167/iovs.14-14679
PURPOSE. To assess optical quality and intraocular scattering using the Optical Quality Analysis System (OQAS) in central serous chorioretinopathy (CSC) and to determine the effects of retinal changes on optical quality. METHODS. This was a prospective, case-control study. Participants were 29 patients with diagnosis of CSC. The control group consisted of the patients’ unaffected eyes. Initial logMAR visual acuity, central macular thickness (by spectral domain optical coherence tomography), and optical quality parameters including modulation transfer function (MTF) cutoff frequency, Strehl (2-dimensional) ratio, and OQAS values at 100%, 20%, and 9% contrast levels were investigated. Objective scattering index (OSI) at 4.0-mm pupil size was assessed in both eyes by using the OQAS. After 3 months of treatment, which included observation and focal laser or injections of antivascular endothelial growth factor, every CSC-affected eye was followed. Main outcome measures were differences between clinical parameters of the CSC-affected eye and those of the control eye and changes in those parameters according to the clinical course of CSC over 3 months. RESULTS. In CSC-affected eyes, the MTF cutoff was significantly reduced (P ¼ 0.01), and OSI was significantly increased (P ¼ 0.03). As macular thickness decreased, OSI decreased but did not become normalized compared to the control eye, nor was it statistically significantly correlated with central macular thickness change. CONCLUSIONS. Retinal change affected optical quality and intraocular scatter. Therefore, when the severity of a cataract is assessed using the OQAS, retinal status should be considered when interpreting OQAS values. Keywords: central serous chorioretinopathy, double-pass system, optical quality, retinal sensitivity
ision can be assessed in terms of visual acuity and visual quality. Visual quality can be expressed as optical quality, composed of ocular scatter, aberration, and diffraction. In order to correct vision, it is important to evaluate not only visual acuity but also optical quality. Recently, different kinds of aberrometers have been developed to detect ocular aberrations.1,2 However, these instruments can only detect aberrations in transparent ocular medium, and they can sometimes underestimate optical quality because they do not assess parameters such as scatter. Furthermore, because in most of these systems the same route used for the inlet of the initial beam is also used as the outlet for detection, the aberrometers can overestimate aberrations. In order to solve these problems, the Optical Quality Analysis System (OQAS; Visiometrics, Terrassa, Spain) was developed.3 The OQAS uses a double-pass method whereby different routes are used for the inlet of the initial laser beam and the outlet of the detection mirror, thus preventing confusion between induction and detection beams. It is the only commercially available device that enables measurement of the effects of optical aberration and the effects of loss of ocular transparency on the optical quality of the human eye.3–5 OQAS detects retinal image quality by using a retinal point spread function, which is captured from the inner retinal surface. Numerous studies have shown that ocular quality is influenced by both aberration and
scattering. However, no studies have investigated the changes in or influences on ocular quality if the retina itself is not normal. Thus, we were curious as to whether OQAS values would remain unchanged in the presence of abnormal lesions in the retina without any other optical problems. Central serous chorioretinopathy (CSC) is a disorder characterized by serous retinal detachment and/or retinal pigment epithelium (RPE) detachment, with changes most often confined to the macula, and associated with leakage of fluid through the RPE into the subretinal space.6 It reportedly affects mostly men in their fourth to fifth decades, with most cases reported in patients from 45 to 51 years of age.7,8 Despite advances in imaging techniques and numerous studies of the disease, the pathophysiology of CSC remains poorly understood. Its clinical course is quite varied, but acute CSC is usually self-limiting in that visual acuity typically recovers within 1 to 3 months without visual sequelae, although recurrences are common.9–11 In this study, we assessed optical quality and intraocular scattering in acute CSC patients who were in either an active disease state or a resolved disease state by using the OQAS, with the aim of obtaining new reference data to assist clinical diagnosis. In addition, we analyzed the effects of retinal change on optical quality by means of objective parameters including modulation transfer function (MTF) cutoff frequency and Strehl
Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc. www.iovs.org j ISSN: 1552-5783
8598
V
IOVS j December 2014 j Vol. 55 j No. 12 j 8599
OQAS in Central Serous Chorioretinopathy ratio; OQAS values (OV) at contrast levels of 100%, 20%, and 9%; and objective scattering index (OSI).
TABLE 1. Demography and Baseline Characteristics Characteristic of CSC Patients
Value
METHODS
Total number of patients Ratio of males to females, % Age, y No. of patients with a history of smoking, % No. of patients with a history of steroid medication, %
29 23:6 (79%) 47.1 6 7.1
This prospective, nonrandomized, case-control study included patients who had an acute attack of CSC between August 2011 and February 2012, presenting at the HanGil Eye Hospital, Incheon, Korea. The study protocol followed guidelines of the Declaration of Helsinki and was approved by the relevant institutional review board and the Clinical Research Ethics Committee of HanGil Eye Hospital. All patients provided informed consent for participation in the study.
Inclusion and Exclusion Criteria Acute onset CSC was defined as CSC that was clinically evident after spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography (FAG), and dilated fundus examination, with symptoms having been present for less than 3 months. Exclusion criteria included a history of CSC in either eye; severe dry eye syndrome, defined as a tear break-up time of less than 5 seconds; clinically significant cataract presenting with a lens opacities classification system (LOCS) III grade of more than 3; retinal comorbidity such as diabetic retinopathy, retinal vein occlusion, or macular degeneration; and any other ocular comorbidity that might affect optical medium, such as corneal opacity or dystrophy. Patients with a history of amblyopia, hyperfluorescence on FAG in the contralateral eye, or more than 1 diopter (D) of astigmatism were also excluded. The experimental and control groups consisted of the CSC-affected eye and the unaffected eye (which did not show any change in the retina), respectively, of each patient. The endpoint of the study was 3 months after the treatment.
Patient Examination A complete ocular examination, SD-OCT, FAG, and OQAS assessment for a 4.0-mm pupil were performed at the initial visit and at 3 months after the treatment in both eyes. Visual acuity was evaluated with a Snellen chart and expressed as a fixed number. Central macular thickness was assessed by using SD-OCT (OPKO/OTI Ophthalmic Technologies, Inc., Toronto, ON, Canada). Thickness was double-checked by the retinal specialist (K. M. L.) manually to confirm the value from the report of SD-OCT. Spherical equivalent was calculated as ðspherical errorÞ þ ðcylinder errorÞ=2
ð1Þ
where each of these errors was evaluated by using an Auto RefKeratometer (RK-5, Canon, Inc., Tokyo, Japan). The optical quality parameters included objective refraction error, MTF cutoff frequency, Strehl ratio, OSI, and OV (at 100%, 20%, and 9% contrast, using the OQAS) for a 4.0-mm pupil. The manifest refractive error of the subjects was fully corrected during these measurements. Spherical error (up to 8 D) was automatically corrected by the double-pass system, and the residual spherical error (more than 8 D) and cylindrical error were corrected with an external lens because the uncorrected refractive error directly affects the optical outcome of the system.
Treatment of Acute CSC Treatment of acute CSC was dependent on patient status and demand. Observation was recommended for at least 1 month. After 1 month of observation, several options were recommended such as focal laser photocoagulation, intravitreal bevacizumab
13 (45%) 2 (7%)
Main symptom Central scotoma Metamorphopsia Micropsia Nonspecific
21 3 4 1
(72%) (10%) (14%) (4%)
OCT configuration SRF Combination of SRF and PED PED only
19 (66%) 9 (31%) 1 (3%)
Treatment Observation Focal laser Intravitreal anti-VEGF injection Failure of treatment
15 (52%) 10 (34%) 4 (14%) 3 (10%) 2 showed secondary CNV (þ) 1 showed unresolved SRF
CNV, choroidal neovascularization; PED, pigment epithelial detachment; SRF, subretinal fluid; VEGF, vascular endothelial growth factor.
injection, or further observation. All potential risks and benefits of each treatment were explained to the patients. Intravitreal injections of bevacizumab (Avastin, 25 mg/mL; Genentech, Inc., South San Francisco, CA, USA) were given after applying at least three drops of topical anesthetic (Alcaine; Alcon, Aliso Viejo, CA, USA). After disinfection and draping, a 0.05-mL volume containing 1.25 mg of bevacizumab was injected into the vitreous cavity, using a 30-gauge needle at a distance of 3.0 to 3.5 mm from the limbus, according to lens status. After the injection, a topical antimicrobial drug, levofloxacin ophthalmic solution (Cravit; Santen Pharmaceutical Co., Ltd., Osaka, Japan) was administered 4 times a day for a week. Focal laser photocoagulation was applied at the leaking point, which was detected by FAG. The Patterned Scanning Laser (PASCAL; OptiMedica Corp., Santa Clara, CA, USA) was used for treatment. Direct treatment of the leaking spot was conducted by using burns of 100 to 200 lm in diameter, unless the leak was immediately under the subfoveal area. Intensity and duration of the laser burns varied between 150 and 250 mW and 20 and 30 ms respectively.
Statistical Analysis Data are means 6 standard deviations. The Mann-Whitney U test was used for statistical comparisons between the CSCaffected group and the control group at the initial visit and between the CSC-affected group after 3 months of treatment and the control group at the initial visit. The Wilcoxon signed rank test was used to compare initial and posttreatment clinical data in the CSC-affected group. Spearman’s q correlation coefficient was used to evaluate the relationships between central macular thickness changes and changes in optical quality parameters in the CSC-affected group after treatment. Statistical analyses were performed using SPSS version 17.0 software (SPSS, Inc., Chicago, IL, USA), and P values of
