Introduction

Empty Sella Syndrome (ESS) is a condition in which the sella turcica, a cavity in the sphenoid bone which contains the pituitary gland. In this condition, the cavity is partially or entirely filled with cerebrospinal fluid, thereby suppressing the pituitary.¹ Thus, ESS may end up in visual and ocular pathway alterations that warrant careful consideration, despite the fact that it is frequently regarded as a benign incidental discovery. Usually for detecting dysfunction that could otherwise go undetected requires clinical evaluation, including visual field testing and optic nerve assessment. Moreover, comparative studies have demonstrated that visual field deficits may improve after surgical intervention even when imaging does not clearly demonstrate herniation of the visual system. Automated perimetry, such as Humphrey or Octopus visual field testing, can reveal defects like bitemporal hemianopia, generalised depression, or other subtle pattern losses.²

Empty Sella Syndrome and Visual Pathways

Anatomy: relation between sella turcica, pituitary gland, and optic chiasm

The pituitary gland is shielded by the sella turcica, which is a little saddle-shaped indentation in the sphenoid bone near the base of the skull. The pituitary, often called the “master gland”, is important for regulating several of the body’s hormonal processes. Because of its close connection to the neighbouring neural structures, particularly the optic chiasm, its position inside the sella is both anatomically and clinically relevant. The next question that arises is what exactly the optic chiasm is. The optic chiasm is nothing but a delicate crossing point where fibres from the nasal halves of both optic nerves converge and project backwards as optic tracts to the brain. This crossover between the nerves allows each half of the brain to process visual inputs from both eyes, which is essential for binocular vision and field perception. Crucially, the optic chiasm is located just above the pituitary gland, separated only by a thin layer of dura called the diaphragm sellae.³ Thus, because of this close anatomical link, any change in the size, pressure, or shape within the sella, for example, in conditions like empty sella syndrome or pituitary tumours, can directly affect the optic chiasm. A pattern noticed in this condition is bitemporal hemianopia, which can result from even a mild upward displacement of the gland or a stretching of the chiasm. Therefore, this indicates why one of the first clinical symptoms of sellar pathology is frequently ocular complaints.⁴ Understanding these anatomical alterations aids healthcare professionals in connecting structural changes in the pituitary region with functional changes in vision. In practice, when patients complain about unexplained visual abnormalities, professionals are prompted to think not only about eye conditions but also about deeper anatomical relationships at the base of the skull where the pituitary and optic pathways merge. 

How can ESS affect vision?

Because of where it occurs in the brain, Empty Sella Syndrome (ESS) can impair eyesight. As mentioned earlier, the pituitary gland is located in the "sella turcica," a little bony seat near the base of the skull. The optic chiasm, where the nerve fibres from both eyes converge and send visual signals to the brain, is located just above this location. The sella swells with fluid in ESS, flattening or compressing the pituitary gland. This may lead to the optic nerves or the optic chiasm being stretched or compressed in certain people, but this may not necessarily be an issue. When this happens, the individual may then begin to notice alterations in their vision. The most common issue is "bitemporal hemianopia," a condition in which both eyes lose the outer portion of their vision fields. Others could suffer from decreased visual acuity, hazy vision, or areas of absent eyesight. On eye exams, the optic nerve itself may sometimes appear pale or injured. If appropriate visual field testing and optic nerve examinations are not performed, these alterations may be subtle and easily overlooked. To ensure that any visual issues are identified early, patients with ESS frequently require routine neurological and ocular examinations.

Visual Field Testing

Role in detecting visual pathway involvement

In order to identify issues along the visual pathway in patients with Empty Sella Syndrome (ESS), visual field testing is crucial. Even minor anatomical alterations in the sella can impair the proper operation of the crossing nerve fibres since the optic chiasm is situated directly above the pituitary gland. Careful visual field testing can identify small flaws long before a patient recognises vision loss, even if these disruptions may not necessarily create evident symptoms at first. 

Common findings 

In order to further understand the condition, it is important to note the common findings. The most common patterns are bitemporal hemianopia, in which the compression of the crossing nasal fibres impacts the outside halves of vision in both eyes, next is generalised depression, and subtle localised defects. Bitemporal hemianopia is the most classical and well-recognised finding.⁸ As mentioned earlier, it happens because when there is compression from below, the nasal fibres of each optic nerve, which cross at the optic chiasm, are the first to be impacted. Patients consequently experience vision loss in both eyes' outer sides. In the initial stages, this could manifest as trouble observing items on the sides, like running into door frames or failing to notice someone coming from the side. The deficiency may worsen over time, resulting in a more profound loss of side vision. When bitemporal hemianopia is detected, it strongly implies that the sellar or parasellar area is involved. It is sometimes regarded as a "signature" indication of chiasmal compression. Not all patients who have ESS develop bitemporal hemianopia. A more widespread decrease in sensitivity throughout the visual field can sometimes be caused by pressure or stretching of the optic nerves and chiasm. This manifests as a "generalised depression," in which the field as a whole appears dimmed or less sensitive than usual. Instead of identifying specific blind spots, individuals frequently describe this as generalised hazy vision or decreased brightness. Correlation with optic nerve examination and neuroimaging is crucial since generalised depression might be confused with other disorders like cataract or glaucoma. Instead of focal compression, generalised depression in ESS may be the result of long-term, persistent strain on the optic pathways. 

Types of visual field tests: automated perimetry (Humphrey, Octopus), confrontation test

One of the most important ways to identify early indicators of optic pathway impairment in Empty Sella Syndrome (ESS) is to assess the visual field. There are numerous testing options, from simple bedside evaluations to advanced automated equipment. Confrontation tests and automatic perimetry (Humphrey or Octopus) are the most often used. 

Confrontation test

This is the simplest and most efficient method for checking visual fields at the patient's bedside. By asking the patient to report when they can see a moving finger or object in different directions, the examiner sits in front of them and compares their visual fields. It is not extremely sensitive, despite being simple, affordable, and a good screening tool. Small scotomas or moderate generalised depression are examples of subtle or early abnormalities that are often overlooked.¹⁰ Confrontation is therefore ideal for preliminary inspections or circumstances in which sophisticated equipment is not available.

Automatic Perimetry (Octopus and Humphrey)

Automated perimetry offers a thorough, numerical evaluation of the field of vision. Small light stimuli are presented in different parts of the field by devices like the Humphrey Field Analyser and Octopus Perimeter, and the patient responds by pressing a button when they identify the target. Areas of normal vision, decreased sensitivity, or total loss are then mapped by the system. Automated perimetry can monitor changes over time and is very sensitive and repeatable. Because of this, it is particularly useful in ESS, where flaws could be little or develop gradually. It is possible to accurately describe patterns, including bitemporal hemianopia, generalised depression, or localised scotomas.

Optic Nerve Evaluation

In Empty Sella Syndrome (ESS), pressure near the optic chiasm may disrupt the optic nerve, which functions as a wire that transmits data from the eye to the brain. Healthcare professionals most likely use three primary methods to assess the health of this nerve: fundus examination, clinical testing, and contemporary imaging such as Optical Coherence Tomography [OCT].

The first step in a clinical examination is to assess visual acuity, primarily by having the patient read letters on an eye chart. Diminished acuity may indicate that the optic nerve is experiencing some sort of stress. Since early optic nerve issues frequently impair colour perception, particularly reds and greens, even before clear vision worsens, colour vision is also examined. Another simple yet crucial test is the pupillary light response, which shows that when light is projected into one eye, both pupils typically contract. This reaction may be absent or sluggish if the optic nerve is weak, which could indicate concealed damage.

The fundus examination enables the physician to examine the optic disc, the point where the nerve enters the eye, up close. The disc in ESS may appear atrophic (nerve fibres have wasted), pale (long-standing injury), or occasionally enlarged if there is increased pressure inside the skull. These appearances offer crucial indicators of the nerve's coping mechanisms.

Correlation Between Visual Field Defects and Optic Nerve Findings

As the optic nerve and the visual fields are closely related in Empty Sella Syndrome (ESS), alterations in one frequently can lead to changes in the other. For instance, on a visual field test, patches of absent vision or dimming are frequently observed if the optic nerve becomes pale. Bitemporal hemianopia, or loss of side vision, is another condition that patients may experience if the optic chiasm is constricted. This condition correlates with nerve fibre destruction observed on the fundus. 

For this reason, depending solely on one kind of test is insufficient. On OCT, a patient may exhibit mild visual field abnormalities or nerve fibre thinning while still being able to read the eye chart effectively. Combining optic nerve evaluation (to see structural changes) and visual field testing (to map functional vision loss) allows doctors to receive a complete picture, identify issues early, and make better treatment and follow-up decisions. 

Summary

Visual field examination and optic nerve evaluation are essential for identifying early visual pathway loss in Empty Sella Syndrome (ESS). While optic nerve testing, which involves fundus alterations, clinical examination, and OCT imaging, discloses structural damage that the patient may not yet be aware of, visual fields aid in identifying functional loss. Accurate diagnosis, close observation, and prompt treatment are guaranteed when both strategies are combined. In order to preserve vision, control systemic effects, and offer comprehensive patient treatment, a multidisciplinary strategy involving ophthalmologists, neurologists, and endocrinologists is crucial because ESS frequently encompasses hormonal, neurological, and visual elements.