Brillouin Scanning in Cataractous Eyes

Pilot Evaluation of Cataractous Lens Stiffening Using a Brillouin Scanning Device

To provide first results for biomechanical properties of cataractous lenses via Brillouin microscopy and correlations between LOCS III grading, cataractous lens scans from optical coherence tomography (OCT), and intraoperative phacoemulsification energy.

Study Overview

• Status: Active, not recruiting
• Conditions: Cataract
• Intervention / Treatment: Device: Brillouin-Microscopy

Detailed Description

Brillouin microscopy (BM), based on Brillouin light scattering theory, has become established in clinical ophthalmology for examining retinal properties, corneal diseases, and age-related lens changes. These BM-derived metrics can portray the intrinsic characteristics of the biosystem, such as the hydration state or the content and anisotropy of corneal collagen fibers, while remaining unaffected by factors such as intraocular pressure and central corneal thickness. In vivo, BM has been shown to characterize the depth-dependent or gradient viscoelastic properties of ocular lenses. Some studies have used this technique to show that the lens nucleus thickens with age, while the thickness of the lens cortex remains constant. Laboratory studies have also shown an increase in the stiffness of the lens nucleus, while later clinical Brillouin measurement studies have shown that the nucleus is clearly distinct from the softer cortex.

Although data on age-related lenticular changes already exist, the in vivo lenticular biomechanics of cataract lenses derived from Brillouin still need to be comprehensively investigated. This is relevant in that the correlation of Brillouin-derived cataract lens mechanics with the Lens Opacity Classification System (LOCS III) and/or the phacoemulsification energy required for cataract surgery may provide useful information about whether the technique could provide valuable insights into lens nuclear stiffening. Very hard or soft nuclei remain one of the major risk factors for the complications occuring during cataract surgery. In the former case, a significantly higher amount of energy is required during phacoemulsification, which can lead to simultaneous damage to the corneal endothelium and prolonged surgical recovery. In the latter case, intraoperative fragmentation of the cell nucleus poses a challenge.

Currently, the type, degree, and (representative) hardness of the cataract lens are assessed preoperatively using a slit lamp examination with the LOCS III system. The degree of lens opacity provides information about how phacoemulsification should be performed, which viscoelastic device should be selected, and what experience the surgeon needs to perform the operation. However, the slit lamp assessment method is susceptible to subjective variability between observers. Given the unique characteristics of assessing the biomechanical properties of the lens in vivo and the short scan time, BM could be used as a novel complementary objective method for surgical decision-making.

• Study Type: Observational
• Enrollment (Actual): 50

Contacts and Locations

Study Locations

• Austria
  • Vienna, Austria, 1140
    • Vienna Institute for Research in Ocular Surgery (VIROS), Hanusch Hospital Vienna

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

50 cataract patients with predominantly nuclear cataract

Description

Inclusion Criteria:

1. Men and women aged above 21 years
2. Normal ophthalmic findings except previous surgery or conditions that impact corneal optical quality such as trauma and corneal scars
3. Willing to sign informed consent before measurements
4. Presence of nuclear cataract according to LOCS III grading and planned cataract surgery

Exclusion Criteria:

Any of the following will exclude a subject from the study:

• Patients with inadequate corneal imaging or corneal scarring that would impact results
• Patients with active ocular infections or inflammatory conditions
• Patients that suffered an eye trauma according to their medical history
• Patients with fixational problems (e.g., nystagmus) or with any medical condition that could interfere with the measurements
• Pregnancy (pregnancy test will be performed in women of reproductive age)

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Cataract Patients; 50 Patients with Cataract

Device: Brillouin-Microscopy; A Brillouin scattering microscopy system (Brillouin Optical Scanning System, Intelon Optics, Boston, MA) will be employed to acquire data. The emission spectrum of the single-frequency tunable laser is fixed at approximately 780 nm near-infrared wavelength. Polarization optics direct the laser beam to the eye and channel backscattered light to a single-mode fiber at the human interface, where the laser light is transmitted over a polarization-maintaining single-mode fiber. To achieve a free-spectral range (FSR) of approximately 16 GHz, a resolution of approximately 0.3 GHz, and an extinction efficiency of -65 dB, the spectrometer employs dual-stage VIPA (virtually imaged phase arrays) etalons. The cornea's optical power is 3-5 mW, which is significantly lower than the utmost permissible exposure level as defined by the American National Standards Institute (ANSI).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Brillouin shift/stiffness metrics	Correlation between Brillouin shift/stiffness metrics and LOCS III grading, OCT lens opacification scans/metrics and and intraoperative phacoemulsification energy	24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Repeatability of Brillouin-Microscopy Measurements	Repeatability as within subject standard deviation, test-retest repeatability, and intraclass-correlation coefficients from BM in cataractous eyes	24 months

Collaborators and Investigators

• Sponsor: Prim. Prof. Dr. Oliver Findl, MBA
• Investigators: Principal Investigator: Oliver Findl, Prof., Dr., Vienna Institute for Research in Ocular Surgery

Study record dates

Study Major Dates

• Study Start (Actual): March 11, 2025
• Primary Completion (Actual): February 1, 2026
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: February 13, 2026
• First Submitted That Met QC Criteria: February 13, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): February 23, 2026
• Last Update Submitted That Met QC Criteria: February 13, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Cataract; Brillouin-Microscopy; Lens Stiffening
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: Brillouin Cataract

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No