Acta Ophthalmologica 2014
Letters to the Editor Images of intravitreal objects projected into a model eye Colin S. H. Tan,1,2 Wei Kiong Ngo1 and Kai Xiong Cheong1 1
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore; 2Fundus Image Reading Center, National Healthcare Group Eye Institute, Singapore doi: 10.1111/aos.12459
Editor
W
e read with interest the article by Kawamura et al. (2013) describing images of intravitreal objects which are projected onto the posterior surface of a model eye. As mentioned by the authors, various studies have reported the visual sensations experienced by patients during many types of ocular surgery, including vitrectomy, cataract surgery and laser in situ keratomileusis (LASIK) (Tan et al. 2003, 2005, 2007; Ang et al. 2007). While the ability of patients to perceive light, colour or general movement may appear more intuitive, some ophthalmologists may wonder how patients are able to perceive detailed images of surgical instruments or the surgeon’s fingers and hands. The study by Kawamura et al. has provided valuable insights into the manner in which images may be perceived by the eye during vitreous surgery. While the visual sensations experienced by patients undoubtedly vary between individual patients, we believe that it will be useful to discuss the possibility of encountering such visual sensations preoperatively with patients. It will be even more valuable to show patients sample images of visual sensations that earlier patients have encountered. Various studies have reported that patients would like to be informed of the potential for intraoperative visual sensations (Tan et al. 2005, 2007), and they would be less likely to be frightened by their visual experiences if they have previously been counselled.
e688
As the proportion of patients who are frightened by their visual experiences during ocular surgery can be as high as 19% (Tan et al. 2005; Ang et al. 2007), any measure that can reduce the fear that they experience will be of value to increase their cooperation and their satisfaction with the surgery. In this regard, the findings reported by Kawamura et al. have the potential to make a major contribution to the preoperative counselling process. Besides being able to inform patients of the potential of experiencing visual sensations, ophthalmologists can now explain that there is a scientific basis to these visual sensations. Without scientific evidence, some patients and even physicians may understandably be sceptical of these claims. With additional studies simulating various common surgical scenarios, it may be possible to show patients photographs or videos of exactly what they may expect to experience intraoperatively and to tailor the counselling process to the type of surgery being discussed. In addition, besides vitreous surgery, it will be very useful to apply these techniques to investigate visual experiences encountered during other common ocular surgeries, including cataract surgery and LASIK, because the optics involved in these surgeries are quite different from those involving instruments in the vitreous. In conclusion, we congratulate the authors on their findings and suggest that these may be expanded in future and applied to patient counselling.
References Ang CL, Au Eong KG, Lee SS, Chan SP & Tan CS (2007): Patients’ expectation and experience of visual sensations during phacoemulsification under topical anaesthesia. Eye (Lond) 21: 1162–1167. Kawamura R, Shinoda K, Inoue M, Noda T, Ohnuma K & Hirakata A (2013): Images of intravitreal objects projected onto posterior surface of model eye. Acta Ophthalmol 91: e561–e566. Tan CS, Rengaraj V & Au Eong KG (2003): Visual experiences of cataract surgery. J Cataract Refract Surg 29: 1453–1454. Tan CS, Mahmood U, O’Brien PD, Beatty S, Kwok AK, Lee VY & Au Eong KG (2005): Visual experiences during vitreous surgery under regional anesthesia: a multicenter study. Am J Ophthalmol 140: 971–975.
Tan CS, Au Eong KG & Lee HM (2007): Visual experiences during different stages of LASIK: Zyoptix XP microkeratome vs Intralase femtosecond laser. Am J Ophthalmol 143: 90–96.
Correspondence: Dr Colin S. H. Tan, MBBS, MMed (Ophth), FRCSEd (Ophth) National Healthcare Group Eye Institute Tan Tock Seng Hospital 11 Jalan Tan Tock Seng Singapore City 308433 Singapore Tel: (+65) 63577726 Fax: (+65) 63577718 Email: [email protected]
Central serous chorioretinopathy and bright light Amir Norouzpour Eye Research Center, Khatam-Al-Anbia Eye Hospital, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran doi: 10.1111/aos.12484
Editor,
W
e read with great interest the article by Yang et al. (2013), reporting that central serous chorioretinopathy (CSCR) is significantly associated with the increased subfoveal choroidal thickness and the choroidal vascular dilation. In that article, the possible causes of choroidal vascular dilation, such as choroidal vascular innervation or endothelin-1 or inflammatory cytokines, have been discussed. As it was pointed out, however, the cause of choroidal vascular dilation has remained unclear. Some data in the literature may be helpful to clarify the cause of choroidal vascular dilation. It was shown that choroidal vessel diameter is mainly influenced by the temperature of the chorioretinal complex (Parver 1991); an increase in the temperature of the chorioretinal complex induces choroidal vascular dilation in both a passive (Parver et al. 1980) and a reflexive manner (Parver et al. 1983; Shih et al.
Acta Ophthalmologica 2014
1999). The chorioretinal complex may be heated up by the light absorption in the melanosomes of the retinal pigment epithelium (RPE) and the choroid (Parver 1991). Therefore, an increase in the environmental light intensity increases the temperature of the macula which is at the focal point of the irradiating lights into the eye. If the focal heat is high enough to induce severe choroidal vasodilation but not to burn the tissue, and if the rate of the heat accumulation is higher than the rate of adaptation of choroidal circulation to bright lights, it may result in a focal serous leakage from the dilated choroidal vessels. In conclusion, CSCR may result from a response of choroidal vessels to an acute increase in the environmental light intensity. The increase in the light intensity may increase the choroidal temperature at the focal point of the irradiating lights into the eye. The resultant focal heat may induce local changes in the choroidal vessels leading to a focal leakage from the choroidal vessels and CSCR. However, this hypothesis should be experimentally tested. Future clinical researches should consider the history of acute increase in the intensity of lights to which patients with CSCR are exposed. Assessment of the relationship of increases in total time spent outdoors with prevalence of CSCR may be helpful. If the hypothesis is proved to be correct, it may be helpful to design more efficient strategies to prevent and manage CSCR.
References Parver LM (1991): Temperature modulating action of choroidal blood flow. Eye 5(Pt. 2): 181–185. Parver LM, Auker C & Carpenter DO (1980): Choroidal blood flow as a heat dissipating mechanism in the macula. Am J Ophthalmol 89: 641–646. Parver LM, Auker CR & Carpenter DO (1983): Choroidal blood flow. III. Reflexive control in human eyes. Arch Ophthalmol 101: 1604–1606. Shih YF, Fitzgerald ME, Cuthbertson SL & Reiner A (1999): Influence of ophthalmic nerve fibers on choroidal blood flow and myopic eye growth in chicks. Exp Eye Res 69: 9–20. Yang L, Jonas JB & Wei W (2013): Choroidal vessel diameter in central serous chorioretinopathy. Acta Ophthalmol 91: e358–e362.
Correspondence: Amir Norouzpour, MD Eye Research Center Khatam-Al-Anbia Eye Hospital Mashhad University of Medical Sciences (MUMS) Mashhad, Iran Tel/Fax: +98-511-7281400 Emails: [email protected]; [email protected]
Central serous chorioretinopathy and bright light: authors reply Lihong Yang,1 Jost B. Jonas2,3 and Wenbin Wei1 1
Beijing Ophthalmology &Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China; 2Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China; 3Department of Ophthalmology, Universit€ atsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
subsides after several months, although the environmental light exposure may have been unchanged. One would also expect to find CSC more often in patients with outdoor professions. These and other questions may be explored in further clinical research as also suggested by Dr Norouzpour.
Reference Norouzpour A (2014): Central serious chorioretinopathy and bright light. Acta Ophthalmol. In press. Yang L, Jonas JB & Wei W (2013): Choroidal vessel diameter in central serous chorioretinopathy. Acta Ophthalmol 91: e358– e362.
Correspondence: Wenbin Wei, MD Beijing Ophthalmology & Visual Sciences Key Lab Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University No.1, Dong Jiao Min Xiang Dong Cheng District 100730 Beijing, China Tel: + 86 10 5826 9152 Fax: + 86 10 5612 9156 Email: [email protected]
doi: 10.1111/aos.12477
Editor, he authors would like to thank Dr Norouzpour for his interest in our study (Yang et al. 2013). In his letter, he postulates that the subfoveal choroidal vascular dilatation in eyes with central serous chorioretinopathy (CSC) may be due to an increase in choroidal temperature, caused by an increase in the environmental light intensity (Norouzpour 2014). If the subfoveal temperature exceeds a critical point, focal serous leakage from the dilated choroidal vessels may occur. This interesting hypothesis needs further exploration. If the hypothesis is valid, one may argue that CSC should occur more frequently in summer than in winter, and that it should be more common within the same ethnic group in geographical regions with higher sun intensity. Another question would be why CSC usually
T
Topical dexamethasone– cyclodextrin microparticle eye drops for uveitic macular oedema Susanne Krag and Anders Hessellund Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark doi: 10.1111/aos.12560
Editor, ystoid macular oedema (CME) is the main cause of visual loss in patients with uveitis (Rothova 2007). The mainstay of treatment of uveitic CME is corticosteroids and to be effective, steroid needs to be given periocularly, intravitreally or systemically. Topical steroid generally is of little benefit for the treatment of posterior segment diseases. Dexamethasone eye drops containing c-cyclodextrin-
C
e689
Letters to the Editor Images of intravitreal objects projected into a model eye Colin S. H. Tan,1,2 Wei Kiong Ngo1 and Kai Xiong Cheong1 1
Department of Ophthalmology, Tan Tock Seng Hospital, Singapore; 2Fundus Image Reading Center, National Healthcare Group Eye Institute, Singapore doi: 10.1111/aos.12459
Editor
W
e read with interest the article by Kawamura et al. (2013) describing images of intravitreal objects which are projected onto the posterior surface of a model eye. As mentioned by the authors, various studies have reported the visual sensations experienced by patients during many types of ocular surgery, including vitrectomy, cataract surgery and laser in situ keratomileusis (LASIK) (Tan et al. 2003, 2005, 2007; Ang et al. 2007). While the ability of patients to perceive light, colour or general movement may appear more intuitive, some ophthalmologists may wonder how patients are able to perceive detailed images of surgical instruments or the surgeon’s fingers and hands. The study by Kawamura et al. has provided valuable insights into the manner in which images may be perceived by the eye during vitreous surgery. While the visual sensations experienced by patients undoubtedly vary between individual patients, we believe that it will be useful to discuss the possibility of encountering such visual sensations preoperatively with patients. It will be even more valuable to show patients sample images of visual sensations that earlier patients have encountered. Various studies have reported that patients would like to be informed of the potential for intraoperative visual sensations (Tan et al. 2005, 2007), and they would be less likely to be frightened by their visual experiences if they have previously been counselled.
e688
As the proportion of patients who are frightened by their visual experiences during ocular surgery can be as high as 19% (Tan et al. 2005; Ang et al. 2007), any measure that can reduce the fear that they experience will be of value to increase their cooperation and their satisfaction with the surgery. In this regard, the findings reported by Kawamura et al. have the potential to make a major contribution to the preoperative counselling process. Besides being able to inform patients of the potential of experiencing visual sensations, ophthalmologists can now explain that there is a scientific basis to these visual sensations. Without scientific evidence, some patients and even physicians may understandably be sceptical of these claims. With additional studies simulating various common surgical scenarios, it may be possible to show patients photographs or videos of exactly what they may expect to experience intraoperatively and to tailor the counselling process to the type of surgery being discussed. In addition, besides vitreous surgery, it will be very useful to apply these techniques to investigate visual experiences encountered during other common ocular surgeries, including cataract surgery and LASIK, because the optics involved in these surgeries are quite different from those involving instruments in the vitreous. In conclusion, we congratulate the authors on their findings and suggest that these may be expanded in future and applied to patient counselling.
References Ang CL, Au Eong KG, Lee SS, Chan SP & Tan CS (2007): Patients’ expectation and experience of visual sensations during phacoemulsification under topical anaesthesia. Eye (Lond) 21: 1162–1167. Kawamura R, Shinoda K, Inoue M, Noda T, Ohnuma K & Hirakata A (2013): Images of intravitreal objects projected onto posterior surface of model eye. Acta Ophthalmol 91: e561–e566. Tan CS, Rengaraj V & Au Eong KG (2003): Visual experiences of cataract surgery. J Cataract Refract Surg 29: 1453–1454. Tan CS, Mahmood U, O’Brien PD, Beatty S, Kwok AK, Lee VY & Au Eong KG (2005): Visual experiences during vitreous surgery under regional anesthesia: a multicenter study. Am J Ophthalmol 140: 971–975.
Tan CS, Au Eong KG & Lee HM (2007): Visual experiences during different stages of LASIK: Zyoptix XP microkeratome vs Intralase femtosecond laser. Am J Ophthalmol 143: 90–96.
Correspondence: Dr Colin S. H. Tan, MBBS, MMed (Ophth), FRCSEd (Ophth) National Healthcare Group Eye Institute Tan Tock Seng Hospital 11 Jalan Tan Tock Seng Singapore City 308433 Singapore Tel: (+65) 63577726 Fax: (+65) 63577718 Email: [email protected]
Central serous chorioretinopathy and bright light Amir Norouzpour Eye Research Center, Khatam-Al-Anbia Eye Hospital, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran doi: 10.1111/aos.12484
Editor,
W
e read with great interest the article by Yang et al. (2013), reporting that central serous chorioretinopathy (CSCR) is significantly associated with the increased subfoveal choroidal thickness and the choroidal vascular dilation. In that article, the possible causes of choroidal vascular dilation, such as choroidal vascular innervation or endothelin-1 or inflammatory cytokines, have been discussed. As it was pointed out, however, the cause of choroidal vascular dilation has remained unclear. Some data in the literature may be helpful to clarify the cause of choroidal vascular dilation. It was shown that choroidal vessel diameter is mainly influenced by the temperature of the chorioretinal complex (Parver 1991); an increase in the temperature of the chorioretinal complex induces choroidal vascular dilation in both a passive (Parver et al. 1980) and a reflexive manner (Parver et al. 1983; Shih et al.
Acta Ophthalmologica 2014
1999). The chorioretinal complex may be heated up by the light absorption in the melanosomes of the retinal pigment epithelium (RPE) and the choroid (Parver 1991). Therefore, an increase in the environmental light intensity increases the temperature of the macula which is at the focal point of the irradiating lights into the eye. If the focal heat is high enough to induce severe choroidal vasodilation but not to burn the tissue, and if the rate of the heat accumulation is higher than the rate of adaptation of choroidal circulation to bright lights, it may result in a focal serous leakage from the dilated choroidal vessels. In conclusion, CSCR may result from a response of choroidal vessels to an acute increase in the environmental light intensity. The increase in the light intensity may increase the choroidal temperature at the focal point of the irradiating lights into the eye. The resultant focal heat may induce local changes in the choroidal vessels leading to a focal leakage from the choroidal vessels and CSCR. However, this hypothesis should be experimentally tested. Future clinical researches should consider the history of acute increase in the intensity of lights to which patients with CSCR are exposed. Assessment of the relationship of increases in total time spent outdoors with prevalence of CSCR may be helpful. If the hypothesis is proved to be correct, it may be helpful to design more efficient strategies to prevent and manage CSCR.
References Parver LM (1991): Temperature modulating action of choroidal blood flow. Eye 5(Pt. 2): 181–185. Parver LM, Auker C & Carpenter DO (1980): Choroidal blood flow as a heat dissipating mechanism in the macula. Am J Ophthalmol 89: 641–646. Parver LM, Auker CR & Carpenter DO (1983): Choroidal blood flow. III. Reflexive control in human eyes. Arch Ophthalmol 101: 1604–1606. Shih YF, Fitzgerald ME, Cuthbertson SL & Reiner A (1999): Influence of ophthalmic nerve fibers on choroidal blood flow and myopic eye growth in chicks. Exp Eye Res 69: 9–20. Yang L, Jonas JB & Wei W (2013): Choroidal vessel diameter in central serous chorioretinopathy. Acta Ophthalmol 91: e358–e362.
Correspondence: Amir Norouzpour, MD Eye Research Center Khatam-Al-Anbia Eye Hospital Mashhad University of Medical Sciences (MUMS) Mashhad, Iran Tel/Fax: +98-511-7281400 Emails: [email protected]; [email protected]
Central serous chorioretinopathy and bright light: authors reply Lihong Yang,1 Jost B. Jonas2,3 and Wenbin Wei1 1
Beijing Ophthalmology &Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China; 2Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China; 3Department of Ophthalmology, Universit€ atsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
subsides after several months, although the environmental light exposure may have been unchanged. One would also expect to find CSC more often in patients with outdoor professions. These and other questions may be explored in further clinical research as also suggested by Dr Norouzpour.
Reference Norouzpour A (2014): Central serious chorioretinopathy and bright light. Acta Ophthalmol. In press. Yang L, Jonas JB & Wei W (2013): Choroidal vessel diameter in central serous chorioretinopathy. Acta Ophthalmol 91: e358– e362.
Correspondence: Wenbin Wei, MD Beijing Ophthalmology & Visual Sciences Key Lab Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University No.1, Dong Jiao Min Xiang Dong Cheng District 100730 Beijing, China Tel: + 86 10 5826 9152 Fax: + 86 10 5612 9156 Email: [email protected]
doi: 10.1111/aos.12477
Editor, he authors would like to thank Dr Norouzpour for his interest in our study (Yang et al. 2013). In his letter, he postulates that the subfoveal choroidal vascular dilatation in eyes with central serous chorioretinopathy (CSC) may be due to an increase in choroidal temperature, caused by an increase in the environmental light intensity (Norouzpour 2014). If the subfoveal temperature exceeds a critical point, focal serous leakage from the dilated choroidal vessels may occur. This interesting hypothesis needs further exploration. If the hypothesis is valid, one may argue that CSC should occur more frequently in summer than in winter, and that it should be more common within the same ethnic group in geographical regions with higher sun intensity. Another question would be why CSC usually
T
Topical dexamethasone– cyclodextrin microparticle eye drops for uveitic macular oedema Susanne Krag and Anders Hessellund Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark doi: 10.1111/aos.12560
Editor, ystoid macular oedema (CME) is the main cause of visual loss in patients with uveitis (Rothova 2007). The mainstay of treatment of uveitic CME is corticosteroids and to be effective, steroid needs to be given periocularly, intravitreally or systemically. Topical steroid generally is of little benefit for the treatment of posterior segment diseases. Dexamethasone eye drops containing c-cyclodextrin-
C
e689
