**8. Congenital anomalies of the optic disc**

#### **8.1. Tilted disc**

The tilted optic disc syndrome is caused by an oblique insertion of the optic nerves in the globe usually inferonasally. Its prevalence is around 0.5% and is commonly bilateral. It is associated with high myopia, astigmatism, visual field defects (usually superotemporal arcuate scoto‐ mas), small optic disc area, low best corrected visual acuity, peripapillary atrophy and choroidal neovascular membrane [63].

Tilted disc analysis with optical coherence tomography (OCT) showed decreased nerve fiber thickness of the superior, inferior and nasal sectors as well as on average, a thicker temporal sector and a more temporally positioned inferior and superior peak sectors (fig 15) [64]. Multifocal electroretinogram also revealed suboptimal macular function [65]

in Blue Mountain Study is 0.19% [69]. The presence of optic disc pit in eyes with open angle glaucoma is a risk factor for progressive optic nerve head damage, advancing visual field defects and presence of disc haemorrhages. They more commonly seen in normal tension

**Figure 17.** Morning glory syndrome. Visual acuity of this eye is hand movements with the other eye having similar

Morning glory syndrome is a rare developmental abnormality of the optic nerve. It is usually unilateral and can be complicated by serous retinal detachmant and choroidal neovasculari‐ zation. The OCT analysis of the RNFL shows large optic discs, increased thickness of the RNFL and decreased macular thickness [71]. Morning glory syndrome is associated with systemic diseases such as frontonasal dysplasia, neurofibromatosis 2 and PHACE (Posterior fossa

Hemangioma(s) of the cervical facial region - Arterial cerebrovascular anomalies, Cardiac

defects, aortic coarctation and other aortic abnormalities - Eye anomalies) syndrome

glaucoma than POAG and are associated with visual field defects close to fixation [70]

**Figure 16.** Peripapillary inferiorly located optic disc pit in a patient with primary open angle glaucoma.

Recognizing a Glaucomatous Optic Disc http://dx.doi.org/10.5772/55157 311

**8.3. Morning glory syndrome (fig 17,18)**

clinical picture. The patient is registered blind.

abnormalities and other structural brain abnormalities -

**Figure 15.** RNFL analysis with OCT in a patient with tilted disc. Slight thinning of the RNFL of the inferonasal sector. This patient has normal visual fields

#### **8.2. Optic disc pit (fig 16)**

Optic disc pits can be congenital or acquired. The former are a rare anomaly with a prevalence of 1:11,000 [66] and are associated with serous detachment of the macula which affects the vision and it can be treated with vitrectomy and gas tamponade. The acquired type is seen more often in pathological myopia and open angle glaucoma [67,68]. Their overall prevalence

**Figure 16.** Peripapillary inferiorly located optic disc pit in a patient with primary open angle glaucoma.

in Blue Mountain Study is 0.19% [69]. The presence of optic disc pit in eyes with open angle glaucoma is a risk factor for progressive optic nerve head damage, advancing visual field defects and presence of disc haemorrhages. They more commonly seen in normal tension glaucoma than POAG and are associated with visual field defects close to fixation [70]

#### **8.3. Morning glory syndrome (fig 17,18)**

**8. Congenital anomalies of the optic disc**

choroidal neovascular membrane [63].

This patient has normal visual fields

**8.2. Optic disc pit (fig 16)**

The tilted optic disc syndrome is caused by an oblique insertion of the optic nerves in the globe usually inferonasally. Its prevalence is around 0.5% and is commonly bilateral. It is associated with high myopia, astigmatism, visual field defects (usually superotemporal arcuate scoto‐ mas), small optic disc area, low best corrected visual acuity, peripapillary atrophy and

Tilted disc analysis with optical coherence tomography (OCT) showed decreased nerve fiber thickness of the superior, inferior and nasal sectors as well as on average, a thicker temporal sector and a more temporally positioned inferior and superior peak sectors (fig 15) [64].

**Figure 15.** RNFL analysis with OCT in a patient with tilted disc. Slight thinning of the RNFL of the inferonasal sector.

Optic disc pits can be congenital or acquired. The former are a rare anomaly with a prevalence of 1:11,000 [66] and are associated with serous detachment of the macula which affects the vision and it can be treated with vitrectomy and gas tamponade. The acquired type is seen more often in pathological myopia and open angle glaucoma [67,68]. Their overall prevalence

Multifocal electroretinogram also revealed suboptimal macular function [65]

**8.1. Tilted disc**

310 Glaucoma - Basic and Clinical Aspects

Morning glory syndrome is a rare developmental abnormality of the optic nerve. It is usually unilateral and can be complicated by serous retinal detachmant and choroidal neovasculari‐ zation. The OCT analysis of the RNFL shows large optic discs, increased thickness of the RNFL and decreased macular thickness [71]. Morning glory syndrome is associated with systemic diseases such as frontonasal dysplasia, neurofibromatosis 2 and PHACE (Posterior fossa abnormalities and other structural brain abnormalities -

Hemangioma(s) of the cervical facial region - Arterial cerebrovascular anomalies, Cardiac defects, aortic coarctation and other aortic abnormalities - Eye anomalies) syndrome

#### **8.4. Optic disc colobomas**

This disc anomaly results from incomplete closure of the embryonic fissure and it is usually unilateral. Possible ophthalmic complications include serous macular detachment, optic disc excavation despite normal IOP and choroidal neovascularization. It is also associated with multiple syndromes such as Patau, Edwards and cat eye syndromes and **CHARGE** (**C**oloboma of the eye - **H**eart defects - **A**tresia of the choanae - **R**etardation of growth and/or development - **G**enital and/or urinary abnormalitie - **E**ar abnormalities and deafness) syndrome. In uncom‐ plicated cases (without serous macular detachment) OCT analysis of the RNFL shows normal fiber layer thickness [72]

head can directly show the drusen. Lee et al [74] reported that the RNFL thickness with spectral domain OCT was increased in all sectors in patients with papilledema as opposed to optic disc drusen in which the RNFL was thicker in the temporal quadrants compared to normal subjects. This can be explained by either a mechanical displacement of the retinal fibers by the drusen which usually lie in the nasal sector towards the temporal sectors or by the compression and subsequent atrophy of the nasal retinal fibers. In longstanding papilledema the retinal fibers are damaged and the average RNFL thickness is reduced. Disc drusen appear hyporeflective

Recognizing a Glaucomatous Optic Disc http://dx.doi.org/10.5772/55157 313

Optic nerve hypoplasia is a congenital disorder that can be uni- or bilateral, segmental or total and the visual acuity can be normal or reduced to no light perception. It can be associated with

Two studies [76,77] found that in patients with superior segmental optic hypoplasia is associated with generalized reduction of the RNFL thickness involving all the sectors and not

Papilledema is the bilateral disc swelling secondary to increased intracranial pressure. Although bilateral it may be asymmetrical. It can be caused by space occupying lesions in the cavity of the skull, idiopathic intracranial hypertension, obstruction of the ventricles, impaired cerebrospinal fluid adsorption by the arachnoid villi, severe systemic hypertension, cerebral

Differential diagnosis includes: malignant hypertension, bilateral optic neuritis with optic nerve head involvement (papillitis), bilateral anterior ischemic optic neuropathy, diabetic papillopathy, Leber's hereditary optic neuropathy, pseudopapilledema (optic disc drusen,

Optical coherence tomography is helpful in diagnosing early papilledema. Vartin et al [78] found that the peripapillary total retinal thickness rather than the conventionally calculated RNFL thickness as measured with spectral domain OCT differentiated early papilledema from normal subjects. Peripapillary total retinal thickness as a diagnostic tool for subtle papilledema was also reported by Skau et al [79]. OCT is useful in the follow up of patients with papilledema. Rebolleda et al [80] followed up patients with papilledema for 12 months following presenta‐ tion and found that RNFL thickness decreased with time and visual field defects improved. Kupersmith et al [81] investigated different causes of optic disc swelling [papilledema, nonarteritic anterior ischemic optic neuropathy (NA-AION ) and optic neuritis] with OCT and scanning laser polarimetry (SLP). Retinal nerve fiber thickness by OCT was increased in papilledema and NA-AION compared to eyes suffering from optic neuritis. This is due to

many syndromes with the most common being de Morsier syndrome.

venous thrombosis, diffuse cerebral oedema following trauma.

on OCT scans [75].

only the superior one.

**9.1. Papilledema**

**9. Acquired optic disc disorders**

hypermetropia), and toxic optic neuropathy.

**8.6. Optic nerve hypoplasia**

**Figure 18.** GDx VCC of the patient in fig 17. Note that the calculation ring is smaller than the optic nerve head and a meaningful analysis of the RNFL in this patient is not possible. The quality of the scan is poor due to nystagmus

#### **8.5. Optic disc drusen**

Optic disc drusen are hyaline bodies in the optic disc substance. Their prevalence is 3.4 – 24 per 1,000 and areusually bilateral [73]. They are usually located most commonly nasally and are difficult to visualize in childhood as they are buried but become more obvious in adoles‐ cence. Ophthalmic complications include choroidal and disc neovascularization and visual field defects. Disc drusen when buried can pose a diagnostic dilemma with papilledema. Disc drusen can be detected by fundus autofluorescence, B scan ultrasonography, computed tomography and recently OCT. Optical coherence tomography scans through the optic nerve head can directly show the drusen. Lee et al [74] reported that the RNFL thickness with spectral domain OCT was increased in all sectors in patients with papilledema as opposed to optic disc drusen in which the RNFL was thicker in the temporal quadrants compared to normal subjects. This can be explained by either a mechanical displacement of the retinal fibers by the drusen which usually lie in the nasal sector towards the temporal sectors or by the compression and subsequent atrophy of the nasal retinal fibers. In longstanding papilledema the retinal fibers are damaged and the average RNFL thickness is reduced. Disc drusen appear hyporeflective on OCT scans [75].

#### **8.6. Optic nerve hypoplasia**

**8.4. Optic disc colobomas**

312 Glaucoma - Basic and Clinical Aspects

fiber layer thickness [72]

**8.5. Optic disc drusen**

This disc anomaly results from incomplete closure of the embryonic fissure and it is usually unilateral. Possible ophthalmic complications include serous macular detachment, optic disc excavation despite normal IOP and choroidal neovascularization. It is also associated with multiple syndromes such as Patau, Edwards and cat eye syndromes and **CHARGE** (**C**oloboma of the eye - **H**eart defects - **A**tresia of the choanae - **R**etardation of growth and/or development - **G**enital and/or urinary abnormalitie - **E**ar abnormalities and deafness) syndrome. In uncom‐ plicated cases (without serous macular detachment) OCT analysis of the RNFL shows normal

**Figure 18.** GDx VCC of the patient in fig 17. Note that the calculation ring is smaller than the optic nerve head and a meaningful analysis of the RNFL in this patient is not possible. The quality of the scan is poor due to nystagmus

Optic disc drusen are hyaline bodies in the optic disc substance. Their prevalence is 3.4 – 24 per 1,000 and areusually bilateral [73]. They are usually located most commonly nasally and are difficult to visualize in childhood as they are buried but become more obvious in adoles‐ cence. Ophthalmic complications include choroidal and disc neovascularization and visual field defects. Disc drusen when buried can pose a diagnostic dilemma with papilledema. Disc drusen can be detected by fundus autofluorescence, B scan ultrasonography, computed tomography and recently OCT. Optical coherence tomography scans through the optic nerve

Optic nerve hypoplasia is a congenital disorder that can be uni- or bilateral, segmental or total and the visual acuity can be normal or reduced to no light perception. It can be associated with many syndromes with the most common being de Morsier syndrome.

Two studies [76,77] found that in patients with superior segmental optic hypoplasia is associated with generalized reduction of the RNFL thickness involving all the sectors and not only the superior one.
