Camiel Boon

Dr. Camiel Boon


Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 September 2018 in Progress in Retinal and Eye Research
Verified
Journal Article
Open access
SVSanne K. Verbakel
Sanne K. Verbakel
RHRamon A.C. van Huet
Ramon A.C. van Huet
CBCamiel Boon
Camiel Boon
AHAnneke I. den Hollander
Anneke I. den Hollander
RCRob W.J. Collin
Rob W.J. Collin
BKB. Jeroen Klevering
B. Jeroen Klevering
Retinitis pigmentosa (RP) encompasses a group of inherited retinal dystrophies characterized by the primary degeneration of rod and cone photoreceptors. RP is a leading cause of visual disability, with a worldwide prevalence of 1:4000. Although the majority of RP cases are non-syndromic, 20-30% of patients with RP also have an associated non-ocular condition. RP typically manifests with night blindness in adolescence, followed by concentric visual field loss, reflecting the principal dysfunction of rod photoreceptors; central vision loss occurs later in life due to cone dysfunction. Photoreceptor function measured with an electroretinogram is markedly reduced or even absent. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging show a progressive loss of outer retinal layers and altered lipofuscin distribution in a characteristic pattern. Over the past three decades, a vast number of disease-causing variants in more than 80 genes have been associated with non-syndromic RP. The wide heterogeneity of RP makes it challenging to describe the clinical findings and pathogenesis. In this review, we provide a comprehensive overview of the clinical characteristics of RP specific to genetically defined patient subsets. We supply a unique atlas with color fundus photographs of most RP subtypes, and we discuss the relevant considerations with respect to differential diagnoses. In addition, we discuss the genes involved in the pathogenesis of RP, as well as the retinal processes that are affected by pathogenic mutations in these genes. Finally, we review management strategies for patients with RP, including counseling, visual rehabilitation, and current and emerging therapeutic options.

1 November 2019 in Progress in Retinal and Eye Research
Verified
Journal Article
Open access
TRThomas J. van Rijssen
Thomas J. van Rijssen
EDElon H.C. van Dijk
Elon H.C. van Dijk
SYSuzanne Yzer
Suzanne Yzer
KOKyoko Ohno-Matsui
Kyoko Ohno-Matsui
JKJan E.E. Keunen
Jan E.E. Keunen
CBCamiel Boon
Camiel Boon
Central serous chorioretinopathy (CSC) is a common cause of central vision loss, primarily affecting men 20-60 years of age. To date, no consensus has been reached regarding the classification of CSC, and a wide variety of interventions have been proposed, reflecting the controversy associated with treating this disease. The recent publication of appropriately powered randomised controlled trials such as the PLACE trial, as well as large retrospective, non-randomised treatment studies regarding the treatment of CSC suggest the feasibility of a more evidence-based approach when considering treatment options. The aim of this review is to provide a comprehensive overview of the current rationale and evidence with respect to the variety of interventions available for treating CSC, including pharmacology, laser treatment, and photodynamic therapy. In addition, we describe the complexity of CSC, the challenges associated with treating CSC, and currently ongoing studies. Many treatment strategies such as photodynamic therapy using verteporfin, oral mineralocorticoid antagonists, and micropulse laser treatment have been reported as being effective. Currently, however, the available evidence suggests that half-dose (or half-fluence) photodynamic therapy should be the treatment of choice in chronic CSC, whereas observation may be the preferred approach in acute CSC. Nevertheless, exceptions can be considered based upon patient-specific characteristics.

1 January 2022 in Progress in Retinal and Eye Research
Verified
Journal Article
Open access
RSRichard F. Spaide
Richard F. Spaide
CCChui Ming Gemmy Cheung
Chui Ming Gemmy Cheung
HMHidetaka Matsumoto
Hidetaka Matsumoto
章岸章治 岸
章治 岸
CBCamiel Boon
Camiel Boon
PMPeter Maloca
Peter Maloca
In central serous chorioretinopathy (CSC), the macula is detached because of fluid leakage at the level of the retinal pigment epithelium. The fluid appears to originate from choroidal vascular hyperpermeability, but the etiology for the fluid is controversial. The choroidal vascular findings as elucidated by recent optical coherence tomography (OCT) and wide-field indocyanine green (ICG) angiographic evaluation show eyes with CSC have many of the same venous patterns that are found in eyes following occlusion of the vortex veins or carotid cavernous sinus fistulas (CCSF). The eyes show delayed choroidal filling, dilated veins, intervortex venous anastomoses, and choroidal vascular hyperpermeability. While patients with occlusion of the vortex veins or CCSF have extraocular abnormalities accounting for the venous outflow problems, eyes with CSC appear to have venous outflow abnormalities as an intrinsic phenomenon. Control of venous outflow from the eye involves a Starling resistor effect, which appears to be abnormal in CSC. Similar choroidal vascular abnormalities have been found in peripapillary pachychoroid syndrome. However, peripapillary pachychoroid syndrome has intervortex venous anastomoses located in the peripapillary region while in CSC these are seen to be located in the macular region. Spaceflight associated neuro-ocular syndrome appears to share many of the pathophysiologic problems of abnormal venous outflow from the choroid along with a host of associated abnormalities. These diseases vary according to their underlying etiologies but are linked by the venous decompensation in the choroid that leads to significant vision loss. Choroidal venous overload provides a unifying concept and theory for an improved understanding of the pathophysiology and classification of a group of diseases to a greater extent than previous proposals.

1 October 2018 in Ophthalmology
Verified
Journal Article
Open access
EDElon H.C. van Dijk
Elon H.C. van Dijk
SFSascha Fauser
Sascha Fauser
MBMyrte B. Breukink
Myrte B. Breukink
RBRocio Blanco-Garavito
Rocio Blanco-Garavito
HGHans Groenewoud
Hans Groenewoud
CBCamiel Boon
Camiel Boon
To compare the anatomic and functional efficacy and safety of half-dose photodynamic therapy (PDT) versus high-density subthreshold micropulse laser (HSML) treatment in patients with chronic central serous chorioretinopathy (cCSC). Open-label, multicenter, randomized controlled clinical trial. Patients with cCSC whose disease had to be confirmed by both clinical characteristics and findings on multimodal imaging. Eligible patients were randomized in a 1:1 allocation ratio. Treatment was evaluated during a follow-up visit, and the same treatment was repeated in patients who still demonstrated subretinal fluid (SRF). The primary end point was the complete disappearance of SRF at the first evaluation visit at 6 to 8 weeks after treatment. As a secondary outcome measure, we assessed this anatomic result at the final evaluation visit at 7 to 8 months after treatment. Other secondary outcomes covered functional improvement and included change in best-corrected visual acuity (BCVA; measured in Early Treatment Diabetic Retinopathy Study [ETDRS] letters), retinal sensitivity (measured using microperimetry), and vision-related quality of life using a validated questionnaire. Between November 2013 and September 2016, 179 patients were included: 89 patients were assigned randomly to half-dose PDT, and 90 were assigned randomly to HSML treatment. At their first evaluation visit, SRF had resolved in 51.2% and 13.8% of patients, respectively (P < 0.001). At their final evaluation visit, a significantly higher percentage of PDT-treated patients demonstrated no SRF (67.2% vs. 28.8%; P < 0.001). Moreover, at the first evaluation visit, the PDT-treated patients showed a significantly higher increase in BCVA (+4.60±6.62 ETDRS letters vs. +1.39±8.99 ETDRS letters; P = 0.011), and a significantly higher increase in retinal sensitivity on microperimetry (+2.01±3.04 dB vs. +0.92±3.65 dB; P = 0.046); however, the improvement in vision-related quality of life was similar (score of +2.87±8.35 vs. +2.56±7.36, respectively; P = 0.800). Half-dose PDT is superior to HSML for treating cCSC, leading to a significantly higher proportion of patients with complete resolution of SRF and functional improvement.

1 December 2016 in Clinical Ophthalmology
Verified
Journal Article
Open access
PDF file
MBMyrte B Breukink
Myrte B Breukink
ADAlexander Jm Dingemans
Alexander Jm Dingemans
AHAnneke I Den Hollander
Anneke I Den Hollander
JKJan Ee Keunen
Jan Ee Keunen
RMRobert E MacLaren
Robert E MacLaren
CBCamiel Boon
Camiel Boon
Purpose: To describe the clinical findings and long-term outcome of patients with chronic central serous chorioretinopathy (cCSC). Materials and methods: This was a retrospective case series in 52 eyes of 36 patients with a follow-up period of at least 1 year. Extensive ophthalmic examination and a validated questionnaire concerning vision-related quality of life (National Eye Institute Visual Function Questionnaire [NEI-VFQ]-39) were analyzed. Results: Mean visual acuity showed a significant decline over time of 0.16 logarithm of minimum angle of resolution ([logMAR] range: -0.22 to 1.3; P=0.009) after a mean follow-up period of 10.6 years. Also, patients reported lower vision-related quality of life based on the NEI-VFQ-39 for almost all categories compared to healthy controls. Macular atrophy was diagnosed more often on optical coherence tomography compared to other diagnostic entities. Retinal pigment epithelium detachments in the macula were documented on optical coherence tomography in 56% of the patients. A significant thinning of foveal thickness was measured over time compared to unaffected fellow eyes (P=0.002). On long-term follow-up, 13 eyes (37%) showed an increase in number of hot spots on fluorescein angiography. Conclusion: This study indicates that cCSC is a progressive disease in many patients, causing a progressive decline in visual acuity, accompanied by lower reported vision-related quality of life. In deciding whether or not to treat, the progressive nature of cCSC should be taken into account in this relatively young and often still professionally active patient group.

1 February 2024 in Progress in Retinal and Eye Research
Verified
Journal Article
Open access
HFHelena M.A. Feenstra
Helena M.A. Feenstra
EDElon H.C. van Dijk
Elon H.C. van Dijk
CCChui Ming Gemmy Cheung
Chui Ming Gemmy Cheung
KOKyoko Ohno-Matsui
Kyoko Ohno-Matsui
TLTimothy Y.Y. Lai
Timothy Y.Y. Lai
CBCamiel Boon
Camiel Boon
Central serous chorioretinopathy (CSC) is a relatively common disease that causes vision loss due to macular subretinal fluid leakage and it is often associated with reduced vision-related quality of life. In CSC, the leakage of subretinal fluid through defects in the retinal pigment epithelial layer's outer blood-retina barrier appears to occur secondary to choroidal abnormalities and dysfunction. The treatment of CSC is currently the subject of controversy, although recent data obtained from several large randomized controlled trials provide a wealth of new information that can be used to establish a treatment algorithm. Here, we provide a comprehensive overview of our current understanding regarding the pathogenesis of CSC, current therapeutic strategies, and an evidence-based treatment guideline for CSC. In acute CSC, treatment can often be deferred for up to 3-4 months after diagnosis; however, early treatment with either half-dose or half-fluence photodynamic therapy (PDT) with the photosensitive dye verteporfin may be beneficial in selected cases. In chronic CSC, half-dose or half-fluence PDT, which targets the abnormal choroid, should be considered the preferred treatment. If PDT is unavailable, chronic CSC with focal, non-central leakage on angiography may be treated using conventional laser photocoagulation. CSC with concurrent macular neovascularization should be treated with half-dose/half-fluence PDT and/or intravitreal injections of an anti-vascular endothelial growth factor compound. Given the current shortage of verteporfin and the paucity of evidence supporting the efficacy of other treatment options, future studies-ideally, well-designed randomized controlled trials-are needed in order to evaluate new treatment options for CSC.