Age-related nonparalytic hypertropia: Clinical features

Area of Science:

• Ophthalmology
• Neuroscience

Background:

• Age-related nonparalytic hypertropia (ARNH) is linked to sagging eye syndrome, characterized by significant excyclotorsion, often greater in the lower eye.
• Understanding the clinical profile and cyclotorsion patterns in ARNH is crucial for diagnosis and management.

Purpose of the Study:

• To detail the clinical characteristics of patients diagnosed with ARNH.
• To quantitatively compare cyclotorsion in ARNH patients against a control group of healthy individuals.

Main Methods:

• The study included 75 patients with ARNH (diagnosed by insidious distance diplopia after age 50, nonparalytic hyperdeviation, and >6 months follow-up) and 75 age/sex-matched controls.
• Objective cyclotorsion was measured using the disc-to-fovea angle (DFA) from fundus photographs.

Main Results:

• Patients with ARNH exhibited a mean hypertropia of 4.6 ± 2.8 prism diopters.
• The disc-to-fovea angle (DFA) was significantly larger in the ARNH group (11.0-11.6°) compared to controls (6.6-9.2°), with p < 0.0001.
• Larger DFA was observed in the non-dominant eye (12.5°) versus the dominant eye (10.2°), and 39% of ARNH patients did not show greater extorsion in the lower eye.

Conclusions:

• The degree of hyperdeviation in ARNH patients was generally small.
• ARNH patients demonstrate increased cyclotorsion compared to normal individuals.
• The frequent absence of greater extorsion in the lower eye in ARNH cases deviates from the typical sagging eye syndrome presentation, suggesting that diminished phoria adaptation may precipitate diplopia.