Introduction:
The optic nerve is a vital eye structure that might face various congenital and acquired defects. One of the optic nerve's multiple abnormalities is a pit or defect in the optic nerve called the optic pit. It is a rarely detected defect, does not have a specifically formulated treatment plan or a diagnosis protocol, and is often identified accidentally on the go. Though it is a congenital anomaly, it only shows up in the later stages of life.
What Are Optic Pits?
It is a congenital defect showing a depression or pocket within the optic nerve due to malformations or incomplete eye formation during eye development. It is a rare condition occurring in the embryo due to the imperfect closure of the superior edge of the embryonic fissure (embryonic fissure, also called the optic fissure, is a significant structure that plays an essential role in the development of the optic nerve).
What Are an Optic Disc and an Optic Nerve?
The optic disc denotes the start of the optic nerve and is also called the optic nerve head. The area where the optic nerve and retina converge at the rear of the inner section of the eye is round and vertically extended. The optic nerve is the major nerve of the eye and is also one of the twelve cranial nerves. It carries the captured visual information from the retina of the eye to the brain. While carrying the impulses to the brain, they pass through the optic disc on the backside of the eye.
What Are the Other Names for Optic Pits?
Optic pits are also called,
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Optic disc pits.
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Optic nerve pits.
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Sometimes, optic holes.
What Are the Causes of Optic Pits?
The cause of this defect is unknown, while some claim it to be autosomal and hereditary, as some families have reported more than one sufferer. In addition, researchers are still debating the cause of optic pits. This condition is not usually associated with other systemic diseases; the affected individuals could be otherwise healthy.
What Are the Characteristic Features of Optic Pits?
The characteristic features of optic pits are;
Appearance: They are seen as small, grayish, hypopigmented depressions in the optic discs (optic nerve head).
Shape: It is often a single, oval-shaped depression.
Optic pits are mostly unilateral (affecting only one eye) and bilateral (affecting both eyes) only in around 15 percent of the cases.
Gender: There is no gender predominance; it affects men and women equally.
Commonly Affected Region: They are usually seen temporally (lateral) to the optic discs but can also be seen centrally or anywhere along the margins of the optic discs.
Prevalence: Researchers say that it occurs in one in 10,000 people.
Age Group: It can occur in any period of life, but the symptoms show up most prevalently in the third and fourth decades of life.
What Is Optic Disc Pit Maculopathy?
The fluid getting accumulates in the macula (a central part of the retina present on the backside of the eye) is called retinal detachment or macular detachment. Optic disc pit maculopathy is when a retinal detachment is associated with an optic pit. Optic disc pit maculopathy is a serious condition and a medical emergency that requires immediate medical intervention. Even with proper treatment, it is impossible to recover vision in this condition. The causes of the fluid accumulation are still unclear, and there is no preventive measure to stop the fluid accumulation.
What Is the Management of Optic Pits?
Asymptomatic Cases:
Regular monitoring through periodic eye exams may be the primary approach if the optic pit is asymptomatic and not causing any visual disturbances. This helps in detecting any potential changes or complications.
Symptomatic Cases:
Optic pits are associated with a higher risk of developing (CSR) Central Serous Retinopathy, where fluid accumulates under the retina.
In cases where this complication occurs and affects vision, treatments may include: Focal laser treatment can seal off leaking points and prevent further fluid accumulation. Vascular endothelial growth factor (VEGF)-targeting drugs can be utilized to stop fluid leakage and treat CSR. In severe cases with significant visual impairment or if other treatments are ineffective, vitrectomy may be considered.
The vitreous gel is removed during this surgical procedure, and the area around the optic pit may be treated or sealed. Some surgeons may consider different surgical techniques, such as laser-assisted induction of chorioretinal adhesion, which aims to close the communication between the pit and the subretinal space. Regardless of the chosen treatment, regular follow-up examinations are crucial to monitor the condition, assess any changes, and determine the effectiveness of the chosen management approach.
What Are the Symptoms Associated With Optic Pits?
The affected individuals are asymptomatic except when fluid accumulates in the macula, which causes progressive vision loss. The symptoms are uncommon in children and usually appear in affected individuals in their 20s or 30s. The common symptoms are changes in vision, blurred vision, seeing a blind spot, etc., which occur only in half of the population suffering from optic pits. Patients with optic pits are said to be highly susceptible to tension-glaucoma.
How Are Optic Pits Diagnosed?
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There is no specific method to diagnose optic pits. Also, the patients remain symptomless for years.
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As it is often asymptomatic, the patient knows they have optic pits only when they go for a routine eye check-up, and the ophthalmologist rules it out.
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Optic pits are ruled out by ophthalmoscopy, a regular eye examination that examines the fundus or rear of the eye, which contains the retina, optic disc, choroid, and blood vessels. Optic pits can be observed as small depressions in the optic nerve head.
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A visual field test determines whether or not it affects vision, assesses the entire field of vision in both the horizontal and vertical directions, and can identify any visual field abnormalities that may be connected to optic pits.
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If the vision is affected, further tests like fluorescein angiography of the retina (a method that uses a special camera to record retinal pictures) are needed. Through comprehensive cross-sectional retina images, optical coherence tomography (OCT) imaging makes it possible to examine the optic nerve and any changes that may be related more closely. It helps in assessing the depth and extent of the pit. OCT of people with optic pits usually shows retinal detachment. Analyzing the activity of the eye's cells that sense light is done with an electroretinogram or ERG.
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In a fluorescein angiogram test, a dye is injected into the circulation, and while the dye moves through the blood vessels in the eye, pictures are taken. It can help in assessing any associated leakage or abnormal blood vessel formation.
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In some cases, brain imaging may be recommended to assess the extent of any associated abnormalities or to rule out other conditions.
How Is an Optic Pit Treated?
The management of optic pits ranges from conservative approaches to surgery. If asymptomatic, patients with optic pits do not require any treatment and are advised to keep track of vision alterations by undergoing eye exams at regular intervals. Cases with fluid accumulation mostly require treatment. However, even in some cases with fluid accumulations, the fluid drains by itself, and the only treatment the ophthalmologists suggest is getting the eye examined at regular intervals.
Oral corticosteroids are used to drain out the fluid accumulation in some cases. Some cases of fluid accumulation require surgery to drain the fluid; this procedure is called a vitrectomy. In severe cases with significant vision impairment due to complications like CSR, a vitrectomy may be considered. During this surgery, the vitreous gel within the eye is removed, and the area around the optic pit might be addressed or sealed to prevent further fluid leakage.
Some surgical techniques involve sealing the communication between the pit and the subretinal space. This aims to prevent or reduce fluid leakage and subsequent damage to the retina. Ongoing research explores innovative surgical methods to close or address optic pits effectively. These techniques aim to minimize fluid leakage and prevent visual impairment.
Conclusion:
Though an utterly unclear condition, it is not serious unless associated with a maculopathy. Most of the optic pits lie dormant and symptomless without causing any discomfort. Optic pits are still under study, and a clear view of this condition will probably be established shortly.
