Objective excyclotorsion in age-related distance esotropia

Area of Science:

• Ophthalmology
• Strabismus Research
• Geriatric Medicine

Background:

• Age-related distance esotropia (ARDE) is commonly attributed to sagging eye syndrome, involving lateral rectus muscle laxity and excyclotorsion.
• Existing research has not quantitatively compared cyclodeviation in ARDE patients with age-matched controls lacking strabismus.

Purpose of the Study:

• To objectively measure and compare cyclotorsion in patients with ARDE against a control group of age-matched individuals without strabismus.
• To investigate the role of lateral rectus sagging in the etiology of ARDE.

Main Methods:

• Fundus photography was utilized to determine the disc-to-fovea angle (DFA), serving as a measure of objective cyclotorsion.
• Two groups were analyzed: 38 ARDE patients (mean age 74.1 years) and 76 age-matched controls (mean age 73.9 years).

Main Results:

• No statistically significant difference in DFA was observed between ARDE patients and the control group in either the right eye (p=0.18), left eye (p=0.54), or the sum of both eyes (p=0.21).
• The average DFA in ARDE patients was 7.7°±2.9° (right) and 10.0°±4.5° (left), compared to 6.8°±3.9° (right) and 9.4°±3.6° (left) in controls.

Conclusions:

• The findings challenge the hypothesis that sagging of the lateral rectus muscle is the exclusive cause of ARDE.
• Reduced phoria adaptation, another age-related change, is proposed as a potential contributing factor to the development of ARDE.