Validation of retinal oximetry vessel selection using fluorescein angiography in patients with optic disc drusen.

Retinal oximetry could provide insights into the pathophysiology of optic nerve disease, including optic disc drusen (ODD). Vessel selection for oximetry analysis is based on morphological characteristics of arterioles and venules and supported by an overlay of estimated blood oxygen saturations. The purpose of this cross-sectional study was to determine the validity of this vessel selection procedure by comparing it with vessel selection supported by video fluorescein angiography (FA). The study included 36 eyes of 36 patients with ODD who underwent retinal oximetry (Oxymap retinal oximeter T1) followed by FA (Heidelberg Spectralis). Two trained graders selected vessel segments in a pre-defined measurement area around the optic disc. One of these graders additionally performed the vessel segment selection with the support of FA images. When performed by the same grader, FA-supported and non-FA-supported vessel selection did not lead to significant differences in total vessel segment length, estimated oxygen saturations or vessel diameters (all p > 0.05). Inter-grader differences were found for arterial and venous segment lengths and arterial saturation (p < 0.05). A similar tendency was found for the arteriovenous saturation difference (p = 0.10). In conclusion, identifying vessel segments for retinal oximetry analysis based on vessel morphology and supported by a color-coded saturation overlay appears to be a valid method without the need for invasive angiography. A numerically small inter-grader variation may influence oximetry results. Further studies of retinal oximetry in ODD are warranted.

Diagnostic dilemma of papilledema and pseudopapilledema.

BACKGROUND: Papilledema is the optic disc swelling caused by increased intracranial pressure (ICP) that can damage the optic nerve and cause subsequent vision loss. Pseudopapilledema refers to optic disc elevation without peripapillary fluid that can arise from several optic disc disorders, with optic disc drusen (ODD) being the most frequent cause. Occasionally, pseudopapilledema patients are mistakenly diagnosed as papilledema, leading to the possibility of unneeded procedures. We aim to thoroughly examine the most current evidence on papilledema and pseudopapilledema causes and several methods for distinguishing between both conditions. METHODS: An extensive literature search was conducted on electronic databases including PubMed and google scholar using keywords that were relevant to the assessed pathologies. Data were collected and then summarized in comprehensive form. RESULTS: Various techniques are employed to distinguish between papilledema and pseudopapilledema. These techniques include Fundus fluorescein angiography, optical coherence tomography, ultrasonography, and magnetic resonance imaging. Lumbar puncture and other invasive procedures may be needed if results are suspicious. CONCLUSION: Papilledema is a sight-threatening condition that may lead to visual affection. Many disc conditions may mimic papilledema. Accordingly, differentiation between papilledema and pseudopailledema is crucial and can be conducted through many modalities.

Updates on ophthalmic imaging features of optic disc drusen, papilledema, and optic disc edema.

PURPOSE OF REVIEW: Optic nerve head elevation can be associated with vision loss. This review provides an update regarding key features of optic disc drusen (ODD) compared with papilledema from increased intracranial pressure and optic disc edema from other causes. RECENT FINDINGS: Clinical history and funduscopic examination are not sufficient to correctly diagnose different causes of optic nerve head elevation. Multimodal ophthalmic imaging is noninvasive and should be used as first-line diagnostic testing to distinguish optic disc edema or papilledema from pseudoedema. Advanced ophthalmic imaging, including enhanced depth imaging optical coherence tomography (EDI-OCT) and autofluorescence imaging, can visualize ODD at high resolution and determine whether there is optic disc edema. OCT angiography does not require contrast and can rapidly visualize papillary, peripapillary, and macular microvasculature and identify important vascular biomarker of ischemia and, potentially, visual prognosis. SUMMARY: Multimodal ophthalmic imaging can help in the diagnosis of ODD and optic disc edema and identify patients at high risk of vision loss and neurological issues in order to ensure appropriate diagnosis and treatment.

Inter-Device Comparison of Blue-Light Autofluorescence in Optic Disc Drusen.

PURPOSE: Monochromatic blue-light fundus autofluorescence has proven to be particularly useful for the detection of optic disc drusen (ODD). The aim of this study was to investigate how accurately novel confocal scanners can detect ODD by means of color fundus and autofluorescence images. METHODS: Images were taken in 20 consecutive patients' eyes with funduscopically visible ODD using the TrueColor Eidon AF (60 × 55°) and the spectral domain Spectralis HRA+OCT (30 × 30°). The features of ODD, including localization, extent, and intensity patterns of autofluorescence were compared and correlated with retinal nerve fiber layer (RNFL) thickness in OCT and perimetry findings. RESULTS: Mean patient age was 46 ± 6 years (6 females, 4 males). The TrueColor Eidon AF enabled accurate localization and extent estimation of the drusen area. Drusen presented as a homogeneous signal. The predilection site of ODD, which was nasally pronounced in >80% of cases, was associated with thinning of the RNFL and corresponding visual field defects. CONCLUSION: The TrueColor Eidon AF allows reliable detection of superficial ODD in nondilated eyes. Extended observational studies are needed to determine the value of this noninvasive, nonmydriatic procedure in terms of follow-up and progression analyses of ODD.

Enhanced Depth Imaging Optical Coherence Tomography of Optic Nerve Head Drusen in Children.

BACKGROUND: To assess the utility of enhanced depth imaging optical coherence tomography (EDI-OCT), compared with other conventional imaging modalities, for detecting and characterizing optic nerve head drusen (ONHD) in children. METHODS: We report a retrospective cross-sectional case series of consecutive pediatric patients (age ≤16 years) with ONHD confirmed using B-scan ultrasonography. All eyes were evaluated using spectral-domain OCT of the optic nerve head in conventional (non-EDI) and EDI modes, fundus autofluorescence (FAF), and standard automated perimetry. Detection rates and the capacity to characterize ONHD were compared between EDI-OCT, non-EDI-OCT, and FAF. RESULTS: Twenty-eight eyes of 15 patients (mean age 11 years; 60% female) were identified with definite ONHD that were confirmed by B-scan ultrasound. Among the technologies, EDI-OCT, non-EDI-OCT, FAF, and automated perimetry had findings consistent with ONHD in 24, 21, 18, and 4 eyes, respectively. EDI-OCT had a significantly better detection capability (86% of eyes) compared with FAF (P = 0.04) but not with non-EDI-OCT (P = 0.15). Similar to results previously reported in adult patients, EDI-OCT detected ONHD at different levels of depth; most were located anterior to the lamina cribrosa. ONHD detected by EDI-OCT appeared as hypo-reflective ovoid regions bordered by hyper-reflective material or as isolated hyper-reflective bands without a hypo-reflective core. The mean greatest diameter of ONHD seen on EDI-OCT was 449.7 (SD ±114.1) µm. CONCLUSIONS: EDI-OCT detects ONHD in most eyes identified as having drusen on B-scan ultrasonography. This technique has the potential to be an effective alternative first-line diagnostic and monitoring tool for ONHD, particularly for detecting buried drusen in children.

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.

The Influence of Volume and Anatomic Location of Optic Disc Drusen on the Sensitivity of Autofluorescence.

BACKGROUND: Optic disc drusen (ODD) are acellular deposits in the optic nerve head. ODD can be diagnosed using different imaging modalities, including enhanced depth imaging optical coherence tomography (EDI-OCT) and autofluorescence (AF). It is unknown which factors determine the sensitivity of AF. The aim of this study was to investigate the effect of volume and anatomic location of ODD on the sensitivity of AF. METHODS: Cross-sectional study. RESULTS: A total of 38 patients (75 eyes) with ODD were included. In 12 of 75 eyes (16%) and in 11 of 38 patients (29%), EDI-OCT detected ODD that were not detected by AF. In 24 distinctly solitary ODD, both increase in ODD volume (P = 0.0388) and a more superficial ODD location (P < 0.0001) increased the possibility of AF detection of ODD, when performing a multivariate analysis. CONCLUSIONS: EDI-OCT is superior to AF in the diagnosis of ODD. Volume and anatomic location of ODD have a significant impact on the sensitivity of AF.

Gaze-Evoked Deformations in Optic Nerve Head Drusen: Repetitive Shearing as a Potential Factor in the Visual and Vascular Complications.

PURPOSE: To determine if ocular ductions deform intrapapillary and peripapillary tissues in optic nerve head drusen (ONHD) and to compare these deformations with healthy eyes and eyes with other optic neuropathies. DESIGN: Observational case series. PARTICIPANTS: Twenty patients with ONHD. METHODS: Axial rasters of the optic nerve from a spectral-domain OCT device (Cirrus 5000; Carl Zeiss Meditec, Inc, Dublin, CA) were used to analyze the shape of the peripapillary basement membrane (ppBM) layer in 20 confirmed cases of ONHD. We compared registered images obtained from 2 eye positions: 10° to 15° in adduction and 30° to 40° in abduction. Geometric morphometrics was used to analyze the shape of the ppBM layer defined by placing 10 equidistant landmarks extending 2500 µm on both sides of the basement membrane opening. We also adapted an image strain tracking technique to measure regional intrapapillary strains in 6 patients. Using manually placed nodes on the reference image (in adduction), an iterative, block-matching algorithm is used to determine local displacements between the reference and its paired image in abduction. Displacement vectors were used to calculate the mean shear and effective strain (percent change). MAIN OUTCOME MEASURES: Peripapillary shape deformations, intrapapillary shear strains, and effective strains. RESULTS: We found a statistically significant difference in the shape of the ppBM layer between abduction and adduction (P < 0.01). The deformation was characterized by a relative posterior displacement temporally in adduction that reversed in abduction. Strain tracking in all 6 patients showed substantial gaze-induced shearing and effective strains. Mean effective strains were 7.5% outside the drusen. Shear and effective strains were significantly larger outside versus within the drusen (P < 0.003 and P < 0.01, respectively). CONCLUSIONS: This study demonstrates that horizontal ocular ductions induce significant shearing deformations of the peripapillary retina and prelaminar intrapapillary tissues. We also found that the deformations in healthy persons are similar in magnitude to ONHD. Based on these findings, we speculate that patients with intrapapillary calcifications exposed to the long-term effects of repetitive shearing (induced by ocular ductions) may contribute to the progressive axonal loss and vascular complications associated with ONHD.

Optical Coherence Tomography Angiography in Optic Nerve Drusen.

AIM: To determine the efficacy of optical coherence tomography angiography (OCT-A) in diagnosing optic nerve head flow impairment in patients with optic nerve drusen. METHODS: Patients affected by optic-nerve head drusen (ONHD) attending the Eye Clinic of the Federico II University of Naples were enrolled in this prospective case series between October 2015 and October 2016. Each patient underwent evaluation of best corrected visual acuity (BCVA), Goldman applanation tonometry, slit-lamp biomicroscopy, fundus examination, standard visual-field testing (perimetry), spectral domain (SD)-OCT and OCT-A. RESULTS: Thirteen patients (6 females and 7 males with a mean age of 22.05 ± 7.54 years) with ONHD (19 eyes) were enrolled. Mean BCVA was 0.16 ± 0.21 LogMar and mean intraocular pressure was 15.68 ± 1.66 mm Hg. The control group constituted 16 individuals (24 eyes). Both ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) parameters were lower in patients than in controls. Similarly, the flow index (U = 134, p = 0.021) and vessel density (U = 90, p = 0.001) were significantly lower in eyes affected by ONHD than in normal eyes. Visual-field parameters did not differ between the 2 groups. GCC parameters were significantly correlated with OCT-A parameters (p < 0.05). No correlation was found between RNFL and OCT-A parameters. CONCLUSIONS: Our data suggest that OCT-A could be an objective method, helpful in the analysis of flow changes in patients with ONHD.

The Optic Disc Drusen Studies Consortium Recommendations for Diagnosis of Optic Disc Drusen Using Optical Coherence Tomography.

BACKGROUND: Making an accurate diagnosis of optic disc drusen (ODD) is important as part of the work-up for possible life-threatening optic disc edema. It also is important to follow the slowly progressive visual field defects many patients with ODD experience. The introduction of enhanced depth imaging optical coherence tomography (EDI-OCT) has improved the visualization of more deeply buried ODD. There is, however, no consensus regarding the diagnosis of ODD using OCT. The purpose of this study was to develop a consensus recommendation for diagnosing ODD using OCT. METHODS: The members of the Optic Disc Drusen Studies (ODDS) Consortium are either fellowship trained neuro-ophthalmologists with an interest in ODD, or researchers with an interest in ODD. Four standardization steps were performed by the consortium members with a focus on both image acquisition and diagnosis of ODD. RESULTS: Based on prior knowledge and experiences from the standardization steps, the ODDS Consortium reached a consensus regarding OCT acquisition and diagnosis of ODD. The recommendations from the ODDS Consortium include scanning protocol, data selection, data analysis, and nomenclature. CONCLUSIONS: The ODDS Consortium recommendations are important in the process of establishing a reliable and consistent diagnosis of ODD using OCT for both clinicians and researchers.

Optic Nerve Head Drusen: The Relationship Between Intraocular Pressure and Optic Nerve Structure and Function.

OBJECTIVE: To determine whether at the time of diagnosis, the intraocular pressure (IOP) in patients with optic nerve head drusen (ONHD) correlates with the perimetric mean deviation (PMD) and the mean retinal nerve fiber layer (RNFL) thickness on optical coherence tomography (OCT). METHODS: This retrospective chart review included adults with ONHD from 2 academic medical centers. Inclusion criteria were age older than 18 years, definitive diagnosis of ONHD, measurement of IOP, and an automated visual field (VF) within 3 months of diagnosis. Exclusion criteria were unreliable VFs, use of IOP-lowering therapy, and visually significant ocular comorbidities. Data were collected from the initial visit. Age, IOP, method of diagnosis of ONHD, mean RNFL thickness, and PMD were recorded. Multiple and logistic regression models were used to control for potential confounders in statistical analyses. RESULTS: Chart review identified 623 patients, of which 146 patients met inclusion criteria. Mean age was 44.2 years (range: 19-82 years). Average PMD of 236 eyes was -5.22 dB (range, -31.2 to +1.21 dB). Mean IOP was 15.7 mm Hg (range: 6-24 mm Hg). Forty eyes (16.9%) underwent RNFL measurement using OCT; mean RNFL thickness was 79.9 µm (range: 43-117 µm). There was no statistically significant association between IOP and PMD (P = 0.13) or RNFL thickness (P = 0.65). Eyes with ocular hypertension tended to have less depressed PMD than those without (P= 0.031). Stratified analyses of visible and buried subgroups yielded similar results. CONCLUSIONS: Lowering IOP in patients with ONHD has been proposed as a means to prevent progression of optic neuropathy. Our study demonstrated that among predominately normotensive eyes, higher IOP was not associated with greater VF loss or thinner RNFL at the time of presentation. This suggests that lowering IOP may not be beneficial in preventing visual loss in normotensive eyes with ONHD.

Optic Disc Drusen in Children: The Copenhagen Child Cohort 2000 Eye Study.

BACKGROUND: Optic disc drusen (ODD) are seen in up to 2.4% of the general population, but the etiology and pathophysiology of the condition is still unknown. The purpose of this study was to determine the prevalence of ODD in a population-based child cohort and to determine if scleral canal diameter and fetal birth and pubertal parameters are associated with the presence of ODD. METHODS: This observational, longitudinal population-based birth cohort study, with a nested case-control, included 1,406 children. Eye examinations were performed when the children were between 11 and 12 years of age. Assessment was performed of optical coherence tomography (OCT) scans from 1,304 children with gradable enhanced depth imaging scans of the optic disc. RESULTS: ODD in one or both eyes were found in 13 (1.0%) of all children. All but one of the cases were found in children with scleral canal diameter in the lowest quartile (1,182-1,399 µm) in the nested case-control study. Children with ODD had a mean disc diameter of 1,339 µm (interquartile range, 30 µm), whereas it was 1,508 µm (interquartile range, 196 µm) in the 130 controls without ODD (P < 0.001). No differences in sex, birth weight, refractive error, and Tanner stages (of puberty) were found between children with and without ODD. CONCLUSIONS: The prevalence of ODD was 1% in a large child cohort examined by OCT. ODD was found only in eyes with a narrow scleral canal, which is consistent with the hypothesis that ODD might arise as a consequence of retinal nerve fiber congestion in the scleral canal.

Doyne Honeycomb Retinal Dystrophy (Malattia Leventinese, Autosomal Dominant Drusen).

In these conditions, drusen are present in childhood, but patients are asymptomatic, with good vision, until their 40s or 50s. Drusen are seen at the macula, around the edge of the optic nerve and/or nasal to the disc, in a radiating pattern (in particular, temporal to macula, as in Figs. 18.1, 18.2, 18.3, 18.4 and 18.5). The periphery is usually spared. Drusen increase in size and number with age. Peripapillary drusen are a characteristic finding. Visual loss later in life is due to pigment hyperplasia, geographic atrophy, and choroidal neovascular membrane (Figs. 18.6 and 18.7). Variability in the clinical picture is common within families.

Enhanced Depth Imaging Optical Coherence Tomography of Optic Nerve Head Drusen: A Comparison of Cases with and without Visual Field Loss.

PURPOSE: Enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD OCT) has been recognized as the most sensitive tool to diagnose optic nerve head drusen (ONHD). The relationship between OCT characteristics and visual loss has not been well documented. This study compares EDI SD OCT-determined morphologic characteristics of drusen in eyes with or without visual field (VF) defects. DESIGN: Descriptive study of patients attending the neuro-ophthalmology service of Moorfields Eye Hospital between January 2013 and October 2014. SUBJECTS: Patients with diagnosed ONHD and EDI SD OCT imaging of the optic nerve head. METHODS: Eyes with and without VF defects were compared with regard to retinal nerve fiber layer (RNFL) thickness, drusen morphology, size, extent, visibility on funduscopy, ultrasound, and fundus autofluorescence. MAIN OUTCOME MEASURES: Difference in OCT characteristics of ONHD between patients with or without VF defects. RESULTS: Of 38 patients, 69 eyes with ONHD were included. Thirty-three eyes had a normal VF with average mean deviation (MD) -0.96 (±1.2) dB and pattern standard deviation (PSD) 1.6 (±0.3) dB (group I), and 36 eyes had VF defects with MD -13.7 (±10.4) dB and PSD 7.2 (±3.6) dB (group II). Mean global RNFL thickness was 62 (±20.9) µm in the latter group and 99.0 (±12.9) µm in group I. In group I, the predominant drusen type was peripapillary drusen, of variable size. In group II, most eyes had confluent (P < 0.02) and large (>500 µm; P < 0.003) drusen, and drusen were more commonly visible on funduscopy (P = 0.001), ultrasound (P = 0.013), and autofluorescence (P = 0.002). Differences between the 2 groups reached statistical significance in a clustered analysis. RNFL thinning and autofluorescence showed relative sparing of the temporal sector. Sixty-four percent of patients with a VF defect in 1 eye also had a VF defect in their fellow eye. CONCLUSIONS: Drusen size and drusen type as classified by OCT morphologic characteristics are significantly different in patients with or without VF defects. Confluent, large, and autofluorescent drusen were more commonly found in patients with VF defects. These findings may assist in clarifying how drusen give rise to visual loss, which is currently not known.

Focal Capillary Dropout Associated With Optic Disc Drusen Using Optical Coherence Tomographic Angiography.

Optic disc drusen may be a cause of visual field defects and visual loss. The mechanism by which this occurs is unclear. We report a patient who developed decreased vision in the right eye and was found to have a heavy burden of superficial optic disc drusen. Optical coherence tomography (OCT) confirmed focal retinal nerve fiber layer thinning that corresponded with the distribution of drusen. OCT angiography, with superficial laminar segmentation, showed focal capillary attenuation overlying the most prominent drusen. These findings demonstrate alterations in the superficial retinal capillary network associated with optic disc drusen.

Anatomical and functional impairment of the nerve fiber layer in patients with optic nerve head drusen.

OBJECTIVE: To evaluate anatomical and functional impairment of the retinal nerve fiber layer (RNFL) using optical coherence tomography (OCT) and automated perimetry in patients with optic nerve head drusen (ONHD). MATERIALS AND METHODS: Sixty-six eyes (66 patients) were studied with ONHD - confirmed by ultrasound B scan - and 70 eyes (70 subjects) of healthy control subjects. ONHD cases were categorised as visible or hidden. Average RNFL thickness and measurements in terms of the quadrants were analysed using both time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). Anatomical and visual field alteration of RNFL between visible and hidden ONHD and control groups were compared. RESULTS: Average RNFL thickness in ONHD patients was 94 µm (TD-OCT) and 88 µm (SD-OCT), and in controls 107 µm (TD-OCT) and 96 µm (SD-OCT), with statistically significant differences between both OCTs. All quadrants analysed showed significant differences except the temporal quadrant. The differences were not significant between hidden drusen and controls.Visual field examination in ONHD showed alterations in 56 %. Alterations were greater in visible drusen in relation to non-visible drusen, but there were no significant differences.The association between RNFL defects in superior, inferior and temporal quadrants and visual field defects showed a statistical relation with visible ONHD, but not in hidden ONHD. CONCLUSIONS: ONHD caused anatomical and functional damage of the RNFL, with a clear association between the alteration in ONHD and visual field defects in visible drusen cases.

[Differentiation of concomitant glaucomatous optic neuropathy in optic disc drusen].

Characteristics of ocular blood flow (OBF) in primary open-angle glaucoma (POAG) in eyes with optic disc drusen have been investigated. The study enrolled 21 patient (35 eyes) with optic disc drusen, of which 7 (8 eyes) were diagnosed with POAG. Besides the standard tests, the ophthalmological assessment included evaluation of OBF (flowmetry) and an individual normal range of intraocular pressure (IOP). The results showed that optic disc drusen are not associated with OBF changes. Concomitant POAG might be suspected in a patient with optic disc drusen whose OBF is significantly decreased and IOP is above the individual normal range. Differentiation of morphofunctional changes in chronic optic neuropathy, which might be due to either glaucomatous optic neuropathy or optic disc drusen, is complicated when actual IOP lies within the average normal range. Ocular blood flow evaluation by means of flowmetry with calculation of an individual normal range of IOP has been demonstrated as a highly effective predictor of concomitant POAG in patients with optic disc drusen.

Acquired vitelliform lesion associated with large drusen.

PURPOSE: The purpose of this study was to describe the association of acquired vitelliform lesion (AVL) and large drusen in patients with non-neovascular age-related macular degeneration. METHODS: A retrospective review of clinical examination and multimodal imaging data of patients with AVL and large drusen seen over a 12-month period was performed. Acquired vitelliform lesion was defined as subretinal accretion of hyperautofluorescent yellowish material within the macular region not due to vitelliform macular dystrophy. Large drusen were diagnosed by the presence of mounded deposits in the subretinal pigment epithelial space between the retinal pigment epithelium and the Bruch membrane using multimodal imaging analysis (color photography, autofluorescence, and spectral domain optical coherence tomography). RESULTS: Thirteen eyes of 9 white patients with a mean age of 74 years were observed to have AVL associated with large drusen. The median visual acuity was 20/60. All AVLs were hyperautofluorescent and were located in the subretinal space between the retinal pigment epithelium and the photoreceptor inner segment/outer segment junction. The AVL in this series had similar color, autofluorescence, and optical coherence tomographic findings as the AVL seen in association with cuticular drusen and subretinal drusenoid deposits. CONCLUSION: Acquired vitelliform lesions, which have previously been related to cuticular drusen and subretinal drusenoid deposits, can occur in association with large drusen. Abnormalities leading to drusen formation or processes that function in parallel to these may be causative in AVL formation.