Are optic disc drusen inherited?

Optic disc drusen: Dystrophic calcification, a potential target for treatment

Optic disc drusen (ODD) are calcified, acellular bodies, seen in the optic nerve head of up to 2% of the population. Although seldomly affecting visual acuity, visual field defects are common, and severe, ischemic complications causing irreversible vision loss are known to occur. Different treatment strategies for ODD have been explored, but so far without success. This review focuses on the unique, calcified property of ODD, describing what we know about ODD pathogenesis and previously tried treatment strategies. In this context, we discuss current knowledge about calcium and pathological calcifications, including intracranial and ocular calcifications. We also explore some of the obstacles that must be addressed to develop a therapy centred on the concept of calcification, should calcification be identified as a pathogenic factor contributing to vision loss.

Influence of Patient Age and Presence of Optic Disc Drusen on Fluctuations in Retinal Nerve Fiber Layer Thickness

BACKGROUND

It is generally believed that optic disc drusen (ODD) change only over long periods of time. Because, in our experience, this does not apply to younger patients, we investigated the natural course of changes of the peripapillary retinal nerve fiber layer (RNFL) in patients with ODD.

METHODS

In this retrospective study, 40 eyes with and 40 eyes without ODD were examined, both cohorts were equally subdivided into younger subjects (20 years or younger) and older subjects (21 years or older). Three optical coherence tomography (OCT) scans of the peripapillary RNFL that had an interval of at least 1 month were required for each patient to be included in this study. The largest difference in total RNFL thickness (delta RNFL-t) and in RNFL thickness of the most differing sector (delta RNFL max) measured by OCT was compared.

RESULTS

The differences in total RNFL thickness and in the most differing RNFL sector in the group of patients with ODD younger than 21 years were significantly larger than in each of the other 3 groups ( P = 0.0001). The other 3 groups did not differ significantly.

CONCLUSIONS

Patients with ODD younger than 21 years have distinct variations in peripapillary RNFL thickness without evidence of increased intracranial pressure. In the absence of further pathological findings or neurological symptoms, an observational approach seems adequate in these patients.

Optic nerve sheath diameter and axial length in patients with optic disc drusen: a cross-sectional study

AIM

Measuring the optic nerve sheath diameter (ONSD) and the anteroposterior axial length of the eye in patients with optic disc drusen (ODD).

METHODS

A total of 43 healthy volunteers and 41 patients with ODD were included in the study. The ONSD and axial length were measured in the posterior position using an ultrasound device (E-Z Scan AB5500 +) probe with a 10 MHz frequency. The ONSD was measured 3 mm behind the globe wall. Receiver operating characteristic (ROC) curve analysis was performed to determine patients with ODD using ONSD. Any p-value of < 0.05 was accepted to demonstrate significance.

RESULTS

The ONSD was significantly higher (5.2 mm and 4.8 mm, p = 0.006, respectively), and the axial length was shorter (21.82 ± 2.15 mm and 23.27 ± 1.96 mm, p = 0.002, respectively) in the ODD group. The spherical equivalent was more commonly seen as hypermetropic in the ODD group (1.00 [- 0.85 to 1.75]). In the ROC analysis to determine the ONSD value in ODD diagnosis, the area under the curve was 0.6754 (95% confidence interval 0.559-0.788, p = 0.006). ONSD cutoff of 5.70 mm had a sensitivity of 0.366 and a specificity of 0.907 to diagnose ODD.

CONCLUSION

In this study, the ONSD was significantly higher in the ODD group. The axial length was shorter in the ODD group. This study is the first in the literature to evaluate the ONSD in patients with optic disc drusen. Further studies are needed in this regard.

Short-term progression of optic disc and macular changes in optic nerve head drusen

PURPOSE

To quantify in patients with optic nerve head drusen (ONHD)changes after 1-year observation in: (i) optic disc and (ii) macular optical coherence tomography (OCT) parameters and (iii) the effect of age at enrolment in the study.

DESIGN

Prospective, cross-sectional observational study using Spectral Domain-OCT (Copernicus; OPTOPOL Technology S.A., Zawiercie, Poland) imaging was carried out in 35 patients with ONHD (age-42.8 ± 19.9 years; males = 15; females = 20) at baseline and after 12 months follow-up.

RESULTS

Patients with ONHD had significant thinning of the surface nerve fibre layer in the central (p = 0.03), superior (p = 0.05) and inferior (p = 0.04) areas; mean ppRNFL thinning (p = 0.0 4) and ppRNFL thinning in the nasal segment (p = 0.028). Retinal thinning in the central (p = 0.001), inner (p = 0.01) and outer (p = 0.002) temporal, outer superior (p = 0.03) and inferior (p = 0.02) areas; borderline ganglion cell layer thinning (p = 0.051) and outer nuclear layer (p = 0.03) thinning in the central retina and outer segment layer thinning nasally (p = 0.01) between the first and the second visit in macula. Correlation of the difference in optic disc and macular parameters with the age at enrolment did not reveal any significance.

CONCLUSIONS

Statistically detectable thinning of the optic nerve and macula structures occurred already after 12 months. The proximity of optic nerve changes to the vascular arcades can possibly be explained by involvement of retinal vessels in the pathophysiology of ONHD.

The status of the choroid in patients with optic disc drusen

PURPOSE

To investigate the subfoveal and peripapillary choroidal thickness (CT) and the choroidal vascularity index (CVI) in patients with optic disc drusen (ODD).

METHODS

This cross-sectional study examined the eyes of 17 patients with ODD and 18 healthy control subjects. The CT values were calculated manually from the images captured by enhanced depth imaging-optical coherence tomography (EDI-OCT). The CVI was defined as the proportion of the vascular area to the total choroidal area at the subfoveal and peripapillary areas after binarization of the EDI-OCT images.

RESULTS

It was found that the mean subfoveal CVI value in the ODD group was significantly lower than that in the control group (p = 0.006). The mean peripapillary CVI values were significantly lower in all of the quadrants in the ODD group when compared with the control group (p = 0.008 for the temporal quadrant, p = 0.014 for the nasal quadrant, p = 0.024 for the superior quadrant, and p = 0.038 for the inferior quadrant). Regarding the CT, there were no significant differences in the subfoveal and peripapillary CT values between the ODD group and the control group (p >  0.05 for all values).

CONCLUSION

The findings of this study indicate ODD to be associated with decreased subfoveal and peripapillary CVI, even though the subfoveal and peripapillary CT values were within the normal range. This result may prove important in relation to identifying a choroidal vascular network that appears to be morphologically normal but microstructurally impaired due to ODD. Further studies are required to verify the significance of CVI in the pathogenesis and complications of ODD.

Papilledema: A Review of the Pathophysiology, Imaging Findings, and Mimics

Increased intracranial pressure is the most common cause of papilledema. Multiple etiologies such as cerebral edema, hydrocephalus, space occupying lesions, infection, and idiopathic intracranial hypertension among others should be considered. Imaging plays a critical role in the detection of pathologies that can cause papilledema. MRI with contrast and CE-MRV, in particular, are key for the diagnosis of idiopathic intracranial hypertension. This review will focus in common and infrequent causes of papilledema, the role of imaging in patients with papilledema as well as its potential mimickers.

Clinical Features of Optic Disc Drusen in an Ophthalmic Genetics Cohort

Materials and Methods

Electronic medical records of patients evaluated in the Ophthalmic Genetics clinic at the National Eye Institute (NEI) between 2008 and 2018 were searched for a superficial ODD diagnosis. Color fundus and autofluorescence images were reviewed to confirm ODD, supplemented with optical coherence tomography (OCT) in uncertain cases when available. Demographic information, examination, and genetic testing were reviewed. Disc areas and disc-to-macula distance to disc diameter ratios (DM : DD) were calculated.

Results

Fifty six of 6207 patients had photographically confirmed ODD (0.9%). Drusen were predominantly bilateral (66%), with a female (62%) and Caucasian (73%) predilection. ODD prevalence in our cohort of patients with inherited retinal degenerations was 2.5%, and ODD were more prevalent in the rod-cone dystrophy subgroup at 2.95% (OR = 3.3 [2.1–5.3], P < 0.001) compared to the ophthalmic genetics cohort. Usher patients were more likely to have ODD (10/132, 7.6%, OR = 9.0 [4.3–17.7], P < 0.001) and had significantly smaller discs compared to the rest of our ODD cohort (disc area: P=0.001, DM : DD: P=0.03). Discussion. While an association between ODD and retinitis pigmentosa has been reported, this study surveys a large cohort of patients with inherited eye conditions and finds the prevalence of superficial ODD is lower than that in the literature. Some subpopulations, such as rod-cone dystrophy and Usher syndrome, had a higher prevalence than the cohort as a whole.

The Relationship between Intraocular Pressure and Optic Nerve Structural and Functional Damage in Patients with Optic Nerve Head Drusen

The aim of this retrospective study was to evaluate if, in ocular normotensive patients, at the time of diagnosis of optic nerve head drusen (ONHD), perimetric mean deviation (PMD) on visual field (VF) examination and retinal nerve fibre layer (RNFL) thickness on optical coherence tomography correlated with intraocular pressure (IOP). There was a significant association between IOP and PMD (Spearman's rho = -0.863, p < .01) and between IOP and RNFL thickness (Spearman's rho = -0.630, p < .01). A higher IOP was associated with a greater functional loss in the VF and a reduction in the RNFL thickness. These results suggest that a clinical trial of IOP reduction should be considered in patients with ONHD to decrease the progression of optic nerve damage over time.

Optic disc drusen: a systematic review : Up-to-date and future perspective

BACKGROUND

Optic disc drusen (ODD) are acellular deposits in the prelaminar optic nerve head. The most accredited theory is that they are secondary to abnormalities in axonal metabolism and degeneration, but the pathogenesis is not clear to date.

CLINICAL MANIFESTATION

Although ODD are often considered a benign condition, the great majority of patients with ODD show visual field defects and are at higher risk for developing anterior ischemic optic neuropathy. ODD are classified as superficial or buried, with the latter being often misdiagnosed as papilledema with optic nerve head swelling, leading to an unnecessary investigation for causes of increased intracranial pressure.

AIM

The recent technological improvements in OCT imaging which allowed an earlier and more certain diagnosis even of the smallest ODD, renovated the interest around this pathology. However, an updated systematic review is still missing. Therefore, the aim of this work is to provide a concise yet comprehensive overview of the current state of art, focusing on pathophysiology, clinical presentation, diagnostic methods, treatment modalities and potential future perspectives of this condition.

Detection of Optic Disc Drusen in Children Using Ultrasound through the Lens and Avoiding the Lens-Point of Care Ultrasound Technique of Evaluation Revisited

AIM

To assess whether the detection rate of optic disc drusen (ODD) in children with swollen optic discs varies if the ultrasound scan (USS) is performed through the lens or avoiding the lens.

METHODS

Retrospective review of the ultrasound machine database for all patients who underwent USS for swollen discs in the department of pediatric ophthalmology, UPMC Children's Hospital of Pittsburgh. Only patients who had both fundus pictures and USS performed (through and avoiding the lens) were included in the study.

RESULTS

A total of 31 patients (62 eyes) were included in the study. USS detected ODD in 44% of eyes (27 of 62 eyes, 15 patients). In 82% of these eyes (22 of 27 eyes), the ODD were not detected initially when scanning was done through the lens but were only detected when scanning was performed avoiding the lens. Ten out of sixteen patients with no ODD on USS had another identifiable cause for disc elevation, including raised intracranial pressure and sleep apnea.

CONCLUSION

Ultrasound is a sensitive diagnostic tool for detecting ODD. The rate of detection of ODD is increased when USS is done avoiding the lens in children where the ODD are usually buried and not as calcified as those found in adults. Under such circumstances, the reduced echogenicity is absorbed by the absorbent pediatric lens, thus limiting the detection rates when scanning through the lens.

The Angioarchitecture of the Optic Nerve Head in Patients with Optic Disc Drusen

The aim was to analyse the optic disc angioarchitecture in optic disc drusen (ODD) patients using computer-based fundus analysis in a case-control study. Compared with controls the ODD group had a significantly more centralised central retinal artery (CRA) emergence (p < 0.001) and primary CRA branching (p = 0.008), a higher number of CRA bifurcations (p = 0.02), a larger vertical optic disc diameter (p = 0.02) and a smaller cup/disc ratio (p < 0.001). The CRA emergence was largely within the nasal zone for both groups. The distinctive angioarchitecture of the optic disc in ODD patients can play a role in understanding the pathogenic cause of ODD.

A study of optic nerve head drusen in 38 pseudoxanthoma elasticum (PXE) patients (64 eyes). Location of optic nerve head drusen in PXE

PURPOSE

To investigate the prevalence and location of optic nerve head drusen and their potential association with other PXE-related ophthalmic abnormalities.

MATERIALS AND METHODS

Thirty-eight of the 155 patients (57 male and 98 female aged 49±17 years) included in this retrospective study had optic nerve head drusen. All of the patients underwent a comprehensive ophthalmic examination, including color images using red-free, blue and red filters, autofluorescence imaging and late-phase ICG frames. Comparative analysis of both groups (optic nerve head drusen or not) was conducted using R statistical software.

RESULTS

The prevalence of optic nerve head drusen in our cohort was 24.5%. In this study, no evidence of a significant link between optic nerve head drusen and other fundus abnormalities was detected. They were more commonly located in the nasal sector than in the temporal sector of the optic disc (P<0.001). They were more frequently situated superonasally than inferonasally (P<0.004), superotemporally (P<0.001) or inferotemporally (P<0.03). No central visual field defect was observed in OND+ patients who were unaffected by macular disorders.

DISCUSSION

We hypothesized this predominantly nasal primary location may result from greater sensitivity in the nasal optic nerve fibers which follow a much more angular path once they arrive in the scleral canal, accounting for accumulation of axoplasmic debris.

CONCLUSION

In PXE, optic nerve head drusen are mostly located in the superonasal quadrant, causing progressive optic nerve invasion but probably no central visual field defects.

Optic Nerve Head Drusen: An Update

Optic nerve head drusen are benign acellular calcium concretions that usually form early in life, just anterior to the lamina cribrosa. Improving imaging using optical coherence tomography suggests they are common and may be present in many clinically normal discs. These drusen may change in appearance in early life, but are generally stable in adulthood, and may be associated with visual field defects, anterior ischaemic optic neuropathy, or rarer complications. Based on long-term clinical data and optical coherence tomography, we propose a refined hypothesis as to the cause of optic disc drusen. Here we summarise recent findings and suggest future studies to better understand the forces involved.

Optic disc drusen: understanding an old problem from a new perspective

Optic disc drusen (ODD) are acellular deposits located in the optic nerve head of up to 2.4% of the population. They may develop as by-products of impaired axonal metabolism in genetically predisposed individuals, in whom a narrow scleral canal is hypothesized to play a role. Although ODD are often considered as benign innocent bystanders, recognized as part of a routine ophthalmological examination, the vast majority of patients with ODD have visual field defects. Optic disc drusen (ODD)-associated complications with severe visual loss, most often due to anterior ischaemic optic neuropathy, are also known to occur. There are no treatments available to prevent or ameliorate the vision loss caused by ODD. In children, the ODD are usually uncalcified and buried within the optic nerve head tissue. In these cases, the condition can be difficult to diagnose, as it often resembles a papilloedema with optic nerve head swelling caused by raised intracranial pressure. During the teenage years, the ODD progressively become more calcified and probably also larger, which allow them to be visible on ophthalmoscopy. With the advent and proper utilization of high-resolution modalities of optical coherence tomography (OCT), it has now become possible to detect even the smallest and most deeply located ODD. This allows for ODD detection at a much earlier developmental stage than has previously been possible and enhances the possibilities of research in underlying mechanisms. A review of the literature on ODD was conducted using the PUBMED database. The review focuses on the current knowledge regarding pathogenesis, diagnostics, clinical disease-tracking methodologies, structure-function relationships and treatment strategies of ODD.

Association of Optic Nerve Head Drusen with Best Vitelliform Macular Dystrophy: A Case Series

Purpose

To report the association of optic nerve head (ONH) drusen with Best vitelliform macular dystrophy (BVMD).

Methods

Chart review.

Patients

Five patients from 3 families.

Results

Multimodal imaging and ophthalmic examination demonstrated findings consistent with ONH drusen, in association with BVMD, in 5 patients.

Conclusion

We report the association of BVMD with ONH drusen in 5 patients. This combination has previously been reported only once. We recommend that patients with a diagnosis of BVMD undergo autofluorescence and ultrasound imaging of the optic nerve to help facilitate this diagnosis, as some ONH drusen can be buried.

Optic Disc Drusen in Tilted Disc

Purpose

To investigate if a congenital anomaly of the head of the optic nerve like such as tilted disc can be a risk factor for the development of optic disc drusen.

Methods

The study was performed retrospectively on the files of 47 patients with optic disc drusen. The diagnosis was confirmed by fluorescein angiography and B-scan ultrasonography. The authors examined the fundus photographs and the fluorescein angiographies of these patients looking for the presence of tilted discs.

Results

Two of the 47 patients with optic nerve drusen had tilted discs as well, about twice the expected rate. Both cases presented a parapapillary hemorrhage.

Conclusions

The concomitant presence of tilted disc and optic disc drusen can have a cause-effect relationship. The axonal crowding in a scleral canal of reduced size, as seen in tilted disc, can compress the nerve fibers against the stiff lamina cribrosa, producing a chronic optic neuropathy leading to drusen.

Optic Disc Drusen and Family History of Glaucoma-Results of a Patient-directed Survey

PURPOSE

Prospective evaluation of family history (FH) of glaucoma and FH of optic disc drusen (ODD) in patients with sonographically confirmed ODD.

PATIENTS AND METHODS

A total of 87 patients with ODD interviewed all their first-degree and second-degree relatives using a detailed questionnaire on whether an ophthalmologist had diagnosed or excluded glaucoma or ocular hypertension (OH). Using a second questionnaire, 62 of these patients also provided information about ODD in their FH. Control groups for FH of glaucoma consisted of 2170 patients with glaucoma or OH evaluated with the same methods and identical questions for FH of glaucoma in a previous study, and of 176 healthy individuals without glaucoma or ODD who were interviewed on family history of glaucoma.

RESULTS

Glaucoma in FH was significantly more frequent in patients with ODD with an incidence of 20.7% compared with healthy controls with an incidence of 2.8%, and half as frequent as in glaucoma patients with an incidence of 40%. ODD in FH were found in 9.7% of patients with ODD.

CONCLUSIONS

As there is a high frequency of family history of glaucoma in patients with ODD, evaluation of FH of ODD and FH of glaucoma is essential in patients with ODD. Glaucoma in FH of ODD patients requires intraocular pressure monitoring and whenever deemed beneficial timely initiation of intraocular pressure-lowering therapy.

The Effect of a Decrease in Intraocular Pressure on Optic Nerve Function in Patients with Optic Nerve Drusen

PURPOSE

The aim of the study was to compare optic nerve function in eyes with brinzolamide-reduced intraocular pressure (IOP) and the fellow eyes of patients with optic disk drusen (ODD).

METHODS

The study comprised 34 patients with bilateral ODD but no signs of any other ocular disease. The eyes with more advanced optic neuropathy were selected for treatment with an IOP-lowering drug, carbonic anhydrase inhibitor (brinzolamide); the fellow eyes served as the control. Static perimetry, pattern electroretinography (PERG), pattern visual-evoked potentials (PVEP), and retinal nerve fiber layer (RNFL) thickness were analyzed. The observation period was 12 months.

RESULTS

The eyes with brinzolamide-reduced IOP exhibited a statistically significant decrease in the mean defect index of static visual field (p = 0.03), an increase in PERG N95 amplitude (from 2.94 to 4.41 µV; p = 0.0047), and RNFL thickness stabilization. A statistically significant decrease in RNFL thickness (from 83.21 to 79.85 µm; p = 0.0017) was found in the control eyes.

CONCLUSIONS

A decrease in IOP in eyes with ODD results in improvement of retinal ganglion cell function and delays the progression of optic neuropathy. PERG should be performed in patients with ODD as it is a sensitive test for monitoring optic neuropathy.

[Optic disc swelling : A compilation of relevant differential diagnoses]

Optic disc oedema describes blurred optic disc margins. It describes an unspecific clinical sign with various possible underlying causal mechanisms. The correct diagnosis and the detection of the underlying disease is however of special clinical importance. This article summarizes the most important differential diagnoses and gives advice to find the correct diagnosis.

Cataract and optic disk drusen in a patient with glycogenosis and di George syndrome: clinical and molecular report

Background

We report the ophthalmic findings of a patient with type Ia glycogen storage disease (GSD Ia), DiGeorge syndrome (DGS), cataract and optic nerve head drusen (ONHD).

Case presentation

A 26-year-old white woman, born at term by natural delivery presented with a post-natal diagnosis of GSD Ia. Genetic testing by array-comparative genomic hybridization (CGH) for DGS was required because of her low levels of serum calcium. The patient has been followed from birth, attending the day-hospital every six months at the San Paolo Hospital, Milan, outpatient clinic for metabolic diseases and previously at another eye center. During the last day-hospital visit, a complete eye examination showed ONHD and cataract in both eyes. Next Generation Sequencing (NGS) was subsequently done to check for any association between the eye problems and metabolic aspects.

Conclusions

This is the first description of ocular changes in a patient with GSD Ia and DGS. Mutations explaining GSD Ia and DGS were found but no specific causative mutation for cataract and ONHD. The metabolic etiology of her lens changes is known, whereas the pathogenesis of ONHD is not clear. Although the presence of cataract and ONHD could be a coincidence; the case reported could suggest that hypocalcemia due to DGS could be the common biochemical pathway.

Multifocal visual evoked potentials for quantifying optic nerve dysfunction in patients with optic disc drusen

PURPOSE

To explore the applicability of multifocal visual evoked potentials (mfVEPs) for research and clinical diagnosis in patients with optic disc drusen (ODD). This is the first assessment of mfVEP amplitude in patients with ODD.

METHODS

MfVEP amplitude and latency from 33 patients with ODD and 22 control subjects were examined. Mean amplitude, mean inner ring (IR) amplitude (0.87-5.67° of visual field) and mean outer ring amplitude (5.68-24° of visual field) were calculated using signal-to-noise ratio (SNR) and peak-to-peak analysis. Monocular latency was calculated using second peak analysis, while latency asymmetry was calculated using cross-correlation analysis.

RESULTS

Compared to normals, significantly decreased mean overall amplitude (p < 0.001), IR amplitude (p < 0.001) and outer ring amplitude (p < 0.001) were found in ODD patients when using SNR. An overall monocular latency delay of 7 ms was seen in ODD patients (p = 0.001). A significant correlation between amplitude and automated perimetric mean deviation as well as retinal nerve fibre layer thickness was found (respectively, p < 0.001 and p = 0.003). The overall highest correlation was found in this order: outer ring, full eye and IR. In the control group, SNR intersubject variability was 17.6% and second peak latency intersubject variability was 2.8%.

CONCLUSION

Decreased mfVEP amplitude in patients with ODD suggests a direct mechanical compression of the optic nerve axons. Our results suggest that mfVEP amplitude is applicable for the assessment of optic nerve dysfunction in patients with ODD.

Optic disk drusen in children

Optic disk drusen occur in 0.4% of children and consist of acellular intracellular and extracellular deposits that often become calcified over time. They are typically buried early in life and generally become superficial, and therefore visible, later in childhood, at the average age of 12 years. Their main clinical significance lies in the ability of optic disk drusen, particularly when buried, to simulate true optic disk edema. Misdiagnosing drusen as true disk edema may lead to an invasive and unnecessary workup for elevated intracranial pressure. Ancillary testing, including ultrasonography, fluorescein angiography, fundus autofluorescence, and optical coherence tomography, may aid in the correct diagnosis of optic disk drusen. Complications of optic disk drusen in children include visual field defects, hemorrhages, choroidal neovascular membrane, nonarteritic anterior ischemic optic neuropathy, and retinal vascular occlusions. Treatment options for these complications include ocular hypotensive agents for visual field defects and intravitreal anti-vascular endothelial growth factor agents for choroidal neovascular membranes. In most cases, however, children with optic disk drusen can be managed by observation with serial examinations and visual field testing once true optic disk edema has been excluded.

Anterior ischemic optic neuropathy in association with optic nervehead drusen

Optic nerve head drusen (ONHD) are incidental ophthalmologic finding in the optic nerve. Patients with ONHD are often asymptomatic, but sometimes present with transient visual obscuration's (TVO), the reported incidence of which is 8.6%. Optic nerve head drusen are of two types: Superficial; visible and deep. The deep-buried drusen mimic papilledema. Because of the varied presentation deep-buried drusen pose a diagnostic challenge to the ophthalmologists. In young patients, they are mistaken for papilledema as it is clinically difficult to detect a buried drusen in the optic nerve head, but are seen on the surface with aging as the retinal nerve fiber layer thins out. They are observed as pale yellow lesions more often located towards the poles. Clinical examination aided with diagnostic tests like computed tomography (CT) orbits and ultrasound B scan can help establish the diagnosis. Herein, we report a rare case of optic nerve head drusen in a young lady, who presented with loss of vision and clinical evaluation and investigations suggested ONHD with anterior ischemic optic neuropathy.

Increased Prevalence of Optic Disc Drusen after Papilloedema from Idiopathic Intracranial Hypertension: On the Possible Formation of Optic Disc Drusen

This is a 25-year observational retrospective review of 372 consecutive participants with optic disc drusen or resolved papilloedema from idiopathic intracranial hypertension. The prevalence of optic disc drusen at 19% among eyes with resolved papilloedema was approximately 10 times higher and significantly increased (p < 0.001) as compared with the occurrence in the general population. Eyes with both resolved papilloedema and optic disc drusen had similar visual acuity and visual field outcome as compared with resolved papilloedema alone. Eyes with exposed drusen had significantly worse visual acuity and visual field outcome (p < 0.001) than buried drusen. The high prevalence of optic disc drusen after papilloedema has resolved suggests a non-coincidental relationship. Optic disc drusen formation can be a sequela of papilloedema.

Assessment of optic nerve head drusen using enhanced depth imaging and swept source optical coherence tomography

BACKGROUND

Optic nerve head drusen (ONHD) are calcific deposits buried or at the surface of the optic disc. Although ONHD may be associated with progressive visual field defects, the mechanism of drusen-related field loss is poorly understood. Methods for detecting and imaging disc drusen include B-scan ultrasonography, fundus autofluorescence, and optical coherence tomography (OCT). These modalities are useful for drusen detection but are limited by low resolution or poor penetration of deep structures. This review was designed to assess the potential role of new OCT technologies in imaging ONHD.

EVIDENCE ACQUISITION

Critical appraisal of published literature and comparison of new imaging devices to established technology.

RESULTS

The new imaging modalities of enhanced depth imaging optical coherence tomography (EDI-OCT) and swept source optical coherence tomography (SS-OCT) are able to provide unprecedented in vivo detail of ONHD. Using these devices it is now possible to quantify optic disc drusen dimensions and assess integrity of neighboring retinal structures, including the retinal nerve fiber layer.

CONCLUSIONS

EDI-OCT and SS-OCT have the potential to allow better detection of longitudinal changes in drusen and neural retina and improve our understanding of drusen-related visual field loss.

Multimodal imaging of optic disc drusen

PURPOSE

To evaluate optic disc drusen, extracellular protein deposits known to contain numerous aggregates of mitochondria, using multimodal modalities featuring optical coherence tomography (OCT) and autofluorescence imaging.

DESIGN

Retrospective observational case series.

METHODS

Eyes with optic nerve drusen were examined with enhanced depth imaging (EDI)-OCT, swept source OCT, and fundus autofluorescence using a fundus camera.

RESULTS

Twenty-six eyes of 15 patients with optic disc drusen were evaluated. EDI-OCT and swept source OCT showed multiple optic disc drusen at different levels; most were located immediately anterior to the lamina cribrosa. The drusen were ovoid regions of lower reflectivity that were bordered by hyperreflective material, and in 12 eyes (46.2%) there were internal hyperreflective foci. The mean diameter of the optic disc drusen as measured in OCT images was 686.8 (standard deviation ± 395.2) μm. There was a significant negative correlation between the diameter of the optic disc drusen and the global retinal nerve fiber layer thickness (r = -0.61, P = .001). There was a significant negative correlation between proportion of the optic disc drusen area occupied by optic nerve drusen as detected by autofluorescence imaging and the global retinal nerve fiber layer thickness (r = -0.63, P = .001).

CONCLUSIONS

Deeper-penetration OCT imaging demonstrated the internal characteristics of optic disc drusen and their relationship with the lamina cribrosa in vivo. This study also showed that both the larger the drusen and the more area of the optic canal occupied by drusen, the greater the associated retinal nerve fiber layer abnormalities.

Bilateral optic disc drusen mimicking papilledema

Background

Optic disc drusen, which are calcified deposits that form anterior to the lamina cribrosa in the optic nerve, may mimic papilledema.

Case Report

We report herein three cases referred to us with suspicion of disc swelling and papilledema. Following ophthalmologic evaluation with B-scan ultrasound, red-free fundus photography, and computed tomography, the diagnosis of papilledema was excluded in all cases and optic disc drusen was diagnosed.

Conclusions

Clinical suspicion of optic disc drusen in cases presenting with swelling of the optic nerve head is important in order to avoid unnecessary interventions and anxiety. The reported cases highlight the commonly encountered clinical presentations and the practical aspects of diagnosis and management of optic disc drusen.

Abnormalities of the optic disc

The optic disc represents the anterior end of the optic nerve, the most forward extension of the central nervous system (CNS). The optic disc gives a rare glimpse into the CNS. Hence, diseases of the CNS are often manifested on fundus examination. Abnormalities of the optic disc may reflect eye disease (such as glaucoma), problems in development (as in various syndromes), or CNS disease (such as increased intracranial pressure). Each optic nerve is composed of about 1.2 million axons deriving from the retinal ganglion cells of one eye. Optic atrophy is a morphological sequela reflecting the loss of many or all of these axons. Myriad diseases such as hereditary, metabolic, tumor, and increased intracranial pressure can lead to optic atrophy. Some diseases, such as optic disc drusen, intracranial masses, orbital tumors, ischemic optic neuropathies, inflammations, and infiltrations, can produce optic disc edema before leading to optic atrophy. A number of new imaging modalities, such as optical coherence tomography (OCT), quantitate the thickness of the peripapillary retinal nerve fiber layer as an indirect measure of axonal loss or swelling. OCT can therefore be used to quantitate pathology or the response to therapy in various generalized CNS conditions, such as multiple sclerosis.

Imaging of optic nerve head drusen: improvements with spectral domain optical coherence tomography

OBJECTIVE

To demonstrate a new algorithm that can determine the shape, location, and volume of optic nerve head drusen (ONHD), which were imaged with spectral domain optical coherence tomography (SDOCT).

METHODS

One exenteration patient and 4 glaucoma patients with bilateral ONHD were recruited from the Massachusetts Eye and Ear Infirmary and from a private practice office. Images were obtained using an experimental SDOCT system developed at the Wellman Center for Photomedicine, Massachusetts General Hospital. With axial resolutions of about 6 mum, SDOCT can obtain 2-dimensional images in 1/29 of a second, compared with commercially available time domain OCT instruments with 10 mum resolution images in 1.28 seconds. The volumes of ONHD were calculated with a new algorithm and were then correlated with visual field mean deviation.

RESULTS

SDOCT can display 2-dimensional images comparable with histology and 3-dimensional videos of ONHD. ONHD are signal-poor regions with high-signaled borders. Larger ONHD volumes are directly correlated with larger mean deviation absolute values on Humphrey visual field testing.

CONCLUSIONS

SDOCT is a potentially better technique for ONHD imaging and may improve the diagnosis and management of patients with both OHND and glaucoma.

Advanced visual field loss secondary to optic nerve head drusen: case report and literature review

BACKGROUND

Optic nerve head drusen (ONHD) is a relatively uncommon condition that results from calcific degeneration of axons within the optic nerve. The abnormal drusen bodies can enlarge, compressing normal nerve structures, and ultimately may result in vision loss. Drusen often are discovered through clinical evaluation with a dilated funduscopic examination. Ancillary testing, including computed tomographic (CT) imaging, B-scan ultrasonography, autofluorescence imaging, nerve fiber layer imaging, and threshold visual field evaluation are helpful to confirm the existence of ONHD and to evaluate for progression of this condition.

CASE REPORT

This case report discusses the clinical presentation of a patient with advanced visual field loss from ONHD and the ancillary testing used to confirm the diagnosis. A complete review of literature on ONHD is discussed.

CONCLUSIONS

Currently, there is no cure or direct treatment for progressive vision loss or complications that may develop from ONHD. Useful diagnostic tools include serial automated threshold visual fields, nerve fiber layer analysis, and fundus photography. It is suggested that ocular hypotensive agents be used to lower intraocular pressure prophylactically to prevent further nerve fiber layer and optic nerve damage.

Peripheral field loss: something old, something new

A 37-year-old patient presented with acute visual field loss diagnosed as non-arteritic anterior ischemic optic neuropathy in the setting of optic nerve drusen. Her visual field loss had progressed when compared to the visual field done 2 years previously. Fundus examination showed bilateral optic nerve head drusen and left retinal nerve fiber layer edema consistent with non-arteritic anterior ischemic optic neuropathy.

Optic disc drusen: Complications and management

BACKGROUND

Disc drusen have been found clinically in 0.3% of the population with up to 91% presenting bilaterally. Disc drusen gradually change in their ophthalmoscopic appearance throughout a patient's lifespan. This case highlights the possible ocular complications of disc drusen and the complexity in their treatment because of the risk of visual acuity loss.

CASE REPORT

A 43-year-old patient with documented bilateral buried disc drusen presented without symptoms for a routine examination. A subretinal neovascular membrane (SNVM) one quarter of a disc diameter in size with an adjacent subretinal hemorrhage was observed in the right eye with a small subretinal hemorrhage in the fellow eye. The patient was evaluated by a retinologist who deferred photocoagulation of the SNVM considering its nasal disc location.

CONCLUSIONS

Diagnosing disc drusen is critical because of the serious pathology they can mimic, including disc edema. Although typically benign, patients with disc drusen should be monitored on a regular basis to rule out ocular complications, which can be potentially sight threatening.

The rate of visual field loss in optic nerve head drusen

PURPOSE

To define the rate of visual field loss in patients with optic nerve head drusen (ONHD).

DESIGN

Retrospective chart review.

METHODS

Goldmann visual field (GVF) testing from initial visit and last follow-up examination were quantified using the modified Esterman grid technique. The rate of visual field loss was calculated by comparing the initial GVF to the last follow-up GVF. A comparative analysis of GVF and age at initial evaluation was performed on all patients with an initial GVF only.

SETTING

Tertiary academic care center.

PARTICIPANTS

Inclusion criteria for the rate analysis: (1) diagnosis of ONHD and (2) at least 36 months of follow-up with serial GVF testing.

EXCLUSION CRITERIA

(1) patients with glaucoma or glaucoma-suspect; (2) history or examination evidence for other ocular disease; and (3) drusen-related macular causes of visual loss.

RESULTS

Thirty-two of 292 charts were included in the rate analysis. The rate of visual field loss was 1.58%. There was no statistically significant difference between men and women (P = .74). One hundred eighty patients were included in the initial visual field analysis. There was a significant negative correlation between age and GVF, with older patients having lower GVF scores with a Spearman correlation of -0.42 (P < 0.0001); 73% of these 180 patients had mild, minimal, or no visual field loss.

CONCLUSIONS

The rate of visual field loss for ONHD over a 36-month interval of time was 1.6% per year. Patients with minimal or no visual field loss were younger, and patients with moderate or severe visual loss were older.

Measurement of the scleral canal using optical coherence tomography in patients with optic nerve drusen

PURPOSE

The etiology of optic nerve drusen (OND) is unknown. A leading hypothesis is that eyes with OND have a small scleral canal. The small scleral canal presumably leads to optic nerve fiber compression, ganglion cell degeneration, extrusion of axonal mitochondria, and calcification of the extruded mitochondria. To determine if subjects with OND have scleral canals that are smaller than subjects without OND, we used optical coherence tomography (OCT) to measure the scleral canal in subjects with and without OND.

DESIGN

Prospective, observational case control study.

METHODS

The study was conducted with subjects recruited from the clinics of the John A. Moran Eye Center, University of Utah Department of Ophthalmology and Visual Sciences. The study population included 25 subjects with OND, 13 unaffected first-degree relatives of OND subjects, and 17 control subjects. All subjects underwent measurement of the scleral canal with OCT. The main outcome measure was the scleral canal area calculated by OCT.

RESULTS

The average areas of the scleral canals were as follows: control eyes: 1.832 mm(2), unaffected eyes of subjects with unilateral OND: 1.836 mm(2), eyes of unaffected first-degree relatives: 2.067 mm(2), and eyes with OND: 2.520 mm(2). The scleral canal area of unaffected eyes of subjects with unilateral drusen was not significantly different from the control. The eyes of first-degree relatives and eyes with OND both had scleral canal areas significantly larger than the control.

CONCLUSIONS

Scleral canal size is probably not an etiologic factor in the pathogenesis of OND.

Progression from Anomalous Optic Discs to Visible Optic Disc Drusen

At age 5, a patient underwent fundus photography that disclosed elevated optic discs without drusen. A head computed tomography did not show optic nerve calcification. At age 9, no disc drusen were evident by ophthalmoscopy, but a CT now showed optic nerve calcification. At age 12, optic disc drusen were faintly evident on photographs; visual fields showed blind spot enlargement OD and an arcuate defect OS. At age 21, he had numerous discrete disc drusen in both eyes, disc pallor, and slight progression of the visual field defects. This case documents the progression from anomalous optic discs to ophthalmoscopically visible optic nerve drusen over a 16-year period.

Optic nerve head drusen

Optic disc drusen are congenital and developmental anomalies of the optic nerve head seen commonly in clinical practice, often as an incidental ophthalmologic finding during routine exams. Optic disc drusen are a form of calcific degeneration in some of the axons of the optic nerve. Visual acuity is often not affected but the visual fields of these patients can be abnormal and deteriorate over time. Optic disc drusen are familial and are not uncommon. They are thought to be the result of pathology at the level of the optic nerve head itself. The diagnosis can be made with clinical findings combined with B scan ultrasound and computed tomography. In addition, newer modalities using optic nerve head tomography are proving to be very useful. Since children as well as adults are affected, it is important to consider optic nerve head drusen in the differential diagnosis of papilledema or optic nerve swelling.

Optic disk drusen

Optic disk drusen occur in 3.4 to 24 per 1,000 population and are bilateral in approximately 75%. Disturbance in the axonal metabolism in the presence of a small scleral canal--regardless of eyelength--is considered responsible for the development. The drusen increase in size, becoming more visible with age due to continuing calcium apposition, and they are associated with visual field defects in a considerable number of patients. Patients do not usually notice these defects, despite their progressive nature over the years, and this indicates an insidious course. A correct diagnosis of optic disk drusen is mandatory, although effective treatment is not yet available. It is most important to differentiate optic disk drusen from papilledema in order to avoid unnecessary neurological examinations, but also to avoid overlooking genuine neurologic disorders. Because optic disk drusen can cause severe visual field defects, patients require individual consultation regarding work issues and whether or not to drive. Optic disk drusen can be accompanied by vascular complications as well. In some cases these vascular changes--for example, choroidal neovascularization--are treatable. Patients with optic disk drusen should undergo regular visual field, IOP, and nerve fiber layer examinations. In patients with deteriorating visual field and borderline IOP, we recommend antiglaucomatous therapy.

Scanning laser polarimetry (SLP) for optic nerve head drusen

Optic nerve head drusen (ONHD) are either clinically invisible or clearly protruding from the disc, in the later case leading to the condition of an irregular, indistinct disc margin or a swollen disc on biomicroscopy. They also may cause visual field defects, even with slow progression. Scanning laser polarimetry (SLP) has been proposed as a rapid, objective and reproducible technology for retinal nerve fiber layer (RNFL) assessment and clinical studies have demonstrated that SLP can help to distinguish between normal and glaucomatous eyes, identify glaucoma suspects and correlates well with visual field defects. The purpose of this study was to evaluate the potential applicability of SLP in 20 consecutive patients with optic nerve head drusen (18 bilateral) that were clinically visible (22 eyes) and invisible (16 eyes). RNFL thickness was studied in patients with and without visual field defects. Patients with visual field defects and ONHD were significantly older and had a small, but significant reduction of visual acuity. Some global SLP parameters (average thickness, ellipse average) were significantly different between subjects with normal and abnormal visual fields. The comparison of the groups with visible and invisible drusen showed that there was no difference in demographic or perimetric data. RNFL thickness measurements were also very similar in both groups. Clinical visibility of drusen was not correlated with RNFL thinning as measured with the GDxTM. SLP assessment, however, was well correlated with functional loss. This objective, non-invasive technology may be an additional option for RNFL evaluation in this condition and an especially useful tool for long-term follow-up.