Choosing the right ophthalmic viscoelastic device (OVD) is one of the most critical decisions in modern eye surgery. With multiple types available-cohesive, dispersive, and viscoadaptive-surgeons often ask: Which one delivers the best balance of space maintenance, endothelial protection, and removal ease?
In this article, we break down each OVD type using clinical rheological behavior, real-world application scenarios, and product data-while highlighting why Singclean® Viscoelastic Solution stands out as a high-performance cohesive OVD for routine and complex eye surgery.
Why OVD Classification Matters in Ophthalmic Surgery
An ophthalmic viscoelastic device serves three main purposes during surgery:
Maintain anterior chamber space for instrument manipulation
Protect corneal endothelial cells from mechanical and thermal damage
Facilitate IOL implantation and removal
According to a comparison table from clinical sources (see Sheet2 of the provided classification data), OVDs fall into three categories:
| Dimension | Cohesive | Dispersive | Viscoadaptive |
|---|---|---|---|
| Zero-shear viscosity | High | Low–moderate | Extremely high (millions mPa·s) |
| Space maintenance | Excellent | Poor | Good |
| Endothelial protection | Poor | Excellent | Good |
| Ease of removal | Easiest | Most laborious | Relatively poor |
Cohesive OVDs: The Workhorse of Routine Cataract Surgery
Cohesive OVDs have high zero‑shear viscosity and strong molecular entanglement. They form a single, non‑dispersing mass that:
Maintains deep anterior chamber depth
Allows quick removal via aspiration
Minimizes postoperative intraocular pressure (IOP) spikes
Example from literature: A clinical study by Behndig (J Cataract Refract Surg 2002) found that cohesive OVDs (like sodium hyaluronate 14 mg/mL) are easier to clear and produce lower IOP changes compared to dispersive blends. However, they offer less endothelial protection-so patient selection is key.
Best for:
Routine phacoemulsification
Patients without corneal risk factors
Surgeons who prioritize rapid removal
Dispersive OVDs: Protection at a Cost
Dispersive OVDs have low or moderate viscosity and weak intermolecular forces. They coat the endothelium effectively but fragment during removal, requiring higher flow rates and longer aspiration time.
Best for:
Fuchs dystrophy
High myopia
Dense nuclear cataracts
Downside: Difficult to remove completely, which can elevate IOP if left in the eye.
Viscoadaptive OVDs: Maximum Performance, Higher Complexity
Viscoadaptive OVDs exhibit extreme zero‑shear viscosity and strong pseudoplasticity. They maintain space nearly as well as cohesive OVDs while offering endothelial protection close to dispersive types. However, they require high injection pressure and are time‑consuming to remove.
Best for:
Pediatric cataracts
Pseudoexfoliation syndrome
Intraoperative floppy‑iris syndrome (IFIS)
Where Does Singclean® Fit? A Cohesive OVD Engineered for Excellence
Key Specifications (Singclean® 15 mg/mL)
| Parameter | Value |
|---|---|
| HA source | Non‑animal, bio‑fermentation |
| Molecular weight | 1–3 million Da |
| Absolute complex viscosity | ≥ 60 Pa·s |
| Shear viscosity | 80,000–250,000 mPa·s |
| Osmolality | 270–350 mOsm/kg (close to tear film) |
| pH | 6.8–7.5 (physiological range) |
| Shelf life | 36 months |
Clinical relevance: With a molecular weight 11–30 times higher than HPMC‑based OVDs, Singclean® provides superior anterior chamber stability during repeated instrument entries.
Competitive Comparison: Singclean® HA vs. HPMC OVDs
| Feature | HPMC OVDs (Dispersive) | Singclean® (Cohesive) |
|---|---|---|
| Component | HPMC | Sodium hyaluronate |
| Molecular weight | ~86,000 Da | 1,000,000–2,600,000 Da |
| Viscosity | ~5,000 mPa·s | ≥ 100,000 mPa·s |
| Pupil expansion | Cannot | Can expand small/unsensitive pupils |
| Anterior chamber deepening | Cannot | Yes |
| Removal | Fragmented | As a single block |
So, Which Is the Best OVD Type?
There is no single "best" ophthalmic viscoelastic device for every case. However:
For routine cataract surgery with rapid turnover and low corneal risk: Cohesive OVDs like Singclean® offer the best combination of space maintenance, ease of removal, and safety.
For high‑risk endothelium: A dispersive or soft‑shell approach is preferred.
For complex or pediatric cases: Viscoadaptive OVDs may be warranted.
Singclean® bridges the gap between performance and practicality. Its high molecular weight sodium hyaluronate ensures stable anterior chambers, while its low concentration (15 mg/mL) minimizes IOP spikes-a balance many surgeons seek.
