Pathologic Myopia Creates Equatorial and Posterior Ocular Deformations

Pathologic myopia results in diverse patterns of equatorial and posterior region deformations, according to research published in JAMA Ophthalmology.

Researchers included 180 individuals with pathologic myopia and atrophic maculopathy (mean age, 55.14 years; 70.6% women) and 10 control group participants in a hospital-based, cross-sectional study to explore ocular deformations associated with pathologic myopia. Participants underwent a comprehensive examination and high-resolution 3-dimensional magnetic resonance imaging, and investigators used this data to compare equatorial and posterior shapes of participants with pathologic myopia and control group individuals.

In eyes with pathologic myopia, the most common equatorial shapes were pyriform (36.7%) and round (25.0%). Protrusions most frequently occurred in the superior temporal (48.5%) and superior nasal (37.9%) regions. The eyes of control group participants, in comparison, mostly had a round shape (80%), with only 2 eyes showing a pyriform or vertical-elliptical shaped equator.

The equatorial shapes demonstrated various equatorial areas, perimeter, maximum diameter, and circularity (P < .001 for all), and circularity was correlated with equatorial shape (r, −0.469; 95% CI, −0.584 to −0.346; P <.001), according to the report. While circularity was similar between individuals with pathologic myopia and round equators and control group participants, patients with the disorder demonstrated larger area, perimeter, and maximum diameter compared with control group individuals (P ≤.001 for all).

Bulb-shaped and multi-distorted posterior shapes (53.9% and 25.6%, respectively) were most common among individuals with pathologic myopia, followed by conical (9.4%), ellipsoidal (5.0%), barrel-shaped (3.9%), and spheroidal (2.2%). Different posterior shapes demonstrated different ocular volume, surface area, and sphericity and showed linear correlations with axial length, according to the report.

“Identification and classification of equatorial morphology is clinically relevant,” according to the study authors. “Predicting equatorial shape based on posterior morphology may help protect these potentially vulnerable regions during surgery involving the equator and alert the examiner to possible peripheral retinal and choroidal degeneration.”

Study limitations include possible selection bias, a single center design, and a small sample size of control group participants.