Pathologic Myopia Globe Shape and Long-Term Prognosis

Overview

Pathologic myopia, also called high myopia, is more than just “needing very strong glasses.” In severe cases, the eye continues to stretch and change shape over time, which can damage the retina, macula, optic nerve, and supporting tissues. This study examined whether the three-dimensional shape of the eye, measured with high-resolution magnetic resonance imaging (MRI), could help predict long-term outcomes over 15 years in people with high myopia.

The central finding was that eye shape matters. Certain abnormal globe shapes, especially nasally distorted and conical eyes, were linked to faster eye elongation and a higher risk of macular thinning, myopic macular degeneration, and visual field problems.

Why Eye Shape Matters in High Myopia

In high myopia, the eyeball is often longer than normal, but the eye does not always stretch in the same way. Some eyes remain relatively smooth and evenly shaped, while others become deformed in specific directions. These differences may reflect how the eye’s wall, posterior pole, and surrounding tissues respond to mechanical stress.

Three-dimensional eye shape may therefore provide more information than a simple axial length measurement alone. Two eyes with the same axial length may not have the same risk if one is evenly elongated and another is irregularly distorted. This study explored whether those shape differences could predict who would do worse over time.

Study Design

This was a prospective cohort study conducted at a single center in China. The participants came from the Zhongshan High Myopia Cohort and all had high myopia, defined as a spherical equivalent of -6.00 diopters or worse in both eyes.

The study began with baseline assessments in August 2011 and followed participants every two years through September 2025. Data analysis was performed from October 2025 to December 2025. MRI was used to classify the eye into one of six globe-shape subtypes:

Spheroidal
Ellipsoidal
Conical
Nasally distorted
Temporally distorted
Barrel shaped

For analysis, spheroidal and ellipsoidal eyes were considered nondeformed, while the other four types were considered deformed.

The study evaluated several important outcomes:

Annual axial elongation rate
Rapid elongation, defined as 0.10 mm per year or more
Macular choroidal thinning, defined as subfoveal choroidal thickness under 62 µm
Progression of myopic macular degeneration (MMD)
Development of posterior staphyloma
Visual impairment, defined as best-corrected visual acuity of 20/40 or worse
Visual field defects

Who Participated

A total of 190 eyes from 95 participants were initially enrolled. Of these, 152 eyes completed follow-up and were included in the final analysis. Among the analyzed eyes, 77 were from female participants, and the average age was 32.3 years.

At baseline, the eye-shape distribution was as follows:

Spheroidal: 83 eyes
Nasally distorted: 25 eyes
Conical: 23 eyes
Ellipsoidal: 11 eyes
Temporally distorted: 5 eyes
Barrel shaped: 5 eyes

Most eyes were therefore either spheroidal or showed one of the abnormal deformed patterns, with nasally distorted and conical shapes being relatively common among the deformed group.

Main Findings: Shape Predicted Eye Growth

Over the 15-year follow-up, axial elongation varied by eye shape. Spheroidal eyes had the slowest elongation rate, about 0.045 mm per year, while nasally distorted eyes had the fastest rate, about 0.095 mm per year.

After adjusting for other factors, nasally distorted eyes elongated 0.050 mm per year faster than the reference group. They were also much more likely to show rapid elongation, with an odds ratio of 5.74. In practical terms, this means that a nasally distorted eye was several times more likely to keep stretching quickly over time than a more regular eye shape.

This is important because continued elongation is a major driver of structural damage in high myopia.

Choroidal Thinning and Macular Risk

The choroid is the vascular layer beneath the retina that helps nourish the outer retina and macula. In pathologic myopia, the choroid often becomes very thin, which may reflect tissue stress and reduced support for the retina.

The study found that deformed eyes as a group had about a 7-fold higher risk of macular choroidal thinning compared with nondeformed eyes. This association remained significant after multivariable adjustment.

Among the specific shapes, nasally distorted and conical eyes carried the greatest risk of both choroidal thinning and progression of myopic macular degeneration. These phenotypes appear to represent more severe structural remodeling of the eye and may be markers of more aggressive disease.

Visual Field Effects

Visual field defects were also more common in the higher-risk shape types, especially nasally distorted and conical eyes. Visual field loss in high myopia can result from a combination of retinal, choroidal, and optic nerve changes. This study suggests that abnormal globe shape may be an early clue that the eye is at increased risk of functional decline, not just structural worsening.

Interestingly, the study’s main emphasis was not only on sight-threatening retinal changes but also on the broader idea that eye shape may influence how the entire visual system deteriorates over time.

Clinical Meaning

The findings support a shift from thinking about high myopia as a single disease to viewing it as a group of structural phenotypes with different prognoses. In everyday eye care, axial length is often measured, but globe shape may add another layer of risk stratification.

If future studies confirm these results, MRI-based shape classification could help clinicians:

Identify patients at higher risk earlier
Schedule closer follow-up for those with aggressive phenotypes
Prioritize monitoring for macular thinning and myopic macular degeneration
Guide counseling about prognosis
Potentially support earlier intervention strategies when available

This does not mean that everyone with a nasally distorted or conical eye will lose vision. Rather, these shapes appear to signal higher risk and the need for more careful surveillance.

How This Fits Into Current Care

At present, management of high myopia focuses on regular eye examinations, imaging of the retina and macula, and prompt treatment of complications such as myopic macular neovascularization when they occur. Preventive strategies in childhood and adolescence, including controlling myopia progression, are also important.

For adults with established high myopia, especially those with deforming globe shapes, long-term care usually includes:

Periodic visual acuity testing
Optical coherence tomography when indicated
Careful monitoring of the macula and choroid
Assessment for posterior staphyloma and degenerative retinal changes
Visual field evaluation when optic nerve or functional problems are suspected

Although MRI is not yet a standard test for all patients with myopia, this study suggests that it may become useful in selected cases or in future risk models.

Strengths and Limitations

This study has several strengths. It was prospective, followed patients for a long period, used standardized imaging, and evaluated both structural and functional outcomes. The long follow-up is especially valuable because high myopia often progresses slowly and complications may take years to appear.

There are also limitations. The study was conducted at a single center, which may limit generalizability. The sample size was modest, and some shape subtypes had very small numbers. MRI-based classification may not be practical in routine care everywhere. In addition, as with all observational research, the study shows association rather than absolute proof that globe shape causes the worse outcomes.

Still, the consistency of the findings makes the overall message compelling: eye shape is not just an anatomic curiosity, but a potentially meaningful marker of prognosis.

Take-Home Message

In this 15-year cohort study of people with high myopia, three-dimensional eye shape strongly influenced long-term outcomes. Nasally distorted and conical eyes had the worst prognosis, with faster axial elongation and higher risks of choroidal thinning, myopic macular degeneration progression, and visual field defects.

The study suggests that baseline globe shape may eventually help personalize follow-up and risk prediction in high myopia. For patients and clinicians alike, the message is clear: in pathologic myopia, the shape of the eye can tell an important part of the story.

Reference

Xiong R, Tan S, Li Y, Li H, Zhu Z, Chen Y, He M, Chen S, Wang W. Pathologic Myopia Globe Shape and Long-Term Prognosis. JAMA Ophthalmology. 2026-05-28. PMID: 42207540. Trial registration: ISRCTN56368396.