Pathological myopia is a major cause of visual impairment and usually affects both eyes. Unilateral presentations are rare, and posterior staphyloma in such cases is even less common. Recognizing these atypical clinical and anatomical features is vital for accurate diagnosis and management. A woman in her 30s with no significant birth or family history presented with progressive right eye protrusion over one year and gradual, painless vision loss in the same eye over five years. Visual acuity was counting fingers at 4 feet in the right eye and 20/25 in the left. Autorefraction showed -24.75 D spherical and -4.35 D cylindrical in the right eye, consistent with high myopia; the left eye had mild astigmatism. Fundoscopy revealed features of pathological myopia with a posterior staphyloma involving the macula. MRI demonstrated asymmetric right globe enlargement with posterior scleral thinning, while A-scan measured an axial length of 34.00 mm in the right eye versus 24.04 mm in the left. Optical coherence tomography (OCT) and B-scan confirmed retinal and choroidal thinning with scleral curvature. Thyroid orbitopathy and mass lesions were excluded. A diagnosis of unilateral pathological myopia with type 2 posterior staphyloma was made. This case highlights the uncommon presentation of unilateral pathological myopia with posterior staphyloma, in contrast to the more common bilateral form. Despite extensive evaluation, no clear cause was identified, underscoring the complexity of the condition. Thorough clinical and imaging assessments are essential for accurate diagnosis. Currently, no definitive treatment exists, so management focuses on monitoring and protecting the unaffected eye.