Findings from a recent study presented at the Association for Research in Vision and Ophthalmology (ARVO) 2025 Annual Meeting identified a novel optical coherence tomography (OCT)-based biomarker for presbyopic accommodation.
Give me some background.
Presbyopes make up about one-fourth of the world’s population, with the condition predominantly affecting people starting in their mid-40s.
And in regards to this research?
This CooperVision-supported study was led by a research team from the University of Rochester Flaum Eye Institute in collaboration with the Instituto de Optica “Daza de Valdés” (IO-CSIC).
Their goal: To estimate anterior segment and crystalline lens geometry on accommodative demand (AD) in presbyopes to better understand residual accommodation and identify biomarkers for accommodative effort that could drive future presbyopia correction strategies.
Let’s get to the study.
Investigators included 24 presbyopic patients (age range: 43-62, spherical equivalence [SE] +1.25-8.25D) who were then classified as either emmetropic or myopic and further organized into three add groups:
- Low (< +1.50D): LE (low emmetrope) and LM (low myope)
- Middle (+1.5-2.25D): ME (middle emmetrope) and MM (middle myope)
- High (> +2.5D): HE (high emmetrope) and HM (high myope)
The anterior segment was imaged using custom 3D quantitative spectral OCT (s-OCT).
- The s-OCT parameters: 840 nm, 25,000 A-scans/s, axial range: 7 mm, axial resolution: 3.4 um
Keep going…
AD was induced monocularly with a Badal optometer (Maltese-cross fixation) to collect various data points, including:
- Static 3D images (300 A-scans x 50 B-scans, 11 mm lateral range)
- Acquisition time: 0.6 seconds, AD: 0-4 D (1 D-steps)
- 2D dynamic images (horizontal B-scans)
- Acquired for 3.8 seconds; AD: 0-1.25-0 D
Subsequently: Custom algorithms were used for geometrical quantification of:
- Anterior chamber depth (ACD)
- Lens thickness (LT)
- Pupil diameter (Pup)
- Anterior (ALR) and posterior lens radii (PLR)
- Accommodation response time (ARt)
- Mean significance of dynamic variations (H)
Findings?
ALR decreased significantly (p < 0.01) with AD in the LE (-0.23 mm/D, r = -0.39) and LM (-0.19mm/D, r = -0.39) subgroups.
- Conversely: PLR did not change significantly in any group.
Pup decreased significantly in the following subgroups:
- LE (-0.28 mm/D, r = -0.76)
- LM (-0.33 mm/D, r = -0.81)
- ME (-0.32 mm/D, r = -0.77)
Note: Four participants (from MM, HE, and HM) paradoxically experienced a significant increase in Pup (+0.20 mm/D).
What else?
ACD decreased (-0.014 mm/D, r = -0.64) and LT increased (+0.013 mm/D, r = 0.59) consistently in all but two eyes.
ARt (averaged across parameters) was significantly higher in emmetropes (LE: 0.83 ± 0.23, ME: 0.74 ± 0.43, HE: 0.79 ± 0.60 s) than myopes (LM: 0.45 ± 0.37, MM: 0.47 ± 0.36, HM: 0.62 ± 0.16 s).
- Further: ARt for LT (0.35 ± 0.32 s) was shortest compared to the other parameters.
Finally: H was highest (1.00) for Pup, LT in myopes (LM, MM, HM), and ACD in the LE, LM, and MM subgroups.
Let’s break down the results.
Overall: Lens curvature and pupil size notably changed with focus demand, particularly in emmetropes and mild to moderate myopia.
However: Changes in other lens aspects varied among individuals, and the time required for the eye to respond to focus changes (i.e., response time) was slower in emmetropes compared to myopes—especially when measuring lens thickness.
Tie it all together for me.
These findings demonstrate that measurable geometrical changes occur in the anterior segment and crystalline lens with accommodative effort in presbyopes, even if diminished (ex., lower amplitudes and higher ARts) in young subjects.
In addition: Crystalline LT appears to be a sensitive marker for accommodation efforts in presbyopes—particuarly in myopic patients.