ISO 10339-1997 PDF

Full title and description

ISO 10339:1997 — Ophthalmic optics — Contact lenses — Determination of water content of hydrogel lenses. This International Standard specifies a laboratory procedure for determining the water content of hydrophilic (hydrogel) contact lenses, intended to provide repeatable, comparable measurement results for manufacturers, test laboratories and regulatory bodies.

Abstract

ISO 10339:1997 defines a gravimetric (loss‑on‑drying) approach for measuring the water content of hydrogel contact lenses, including requirements for sample equilibration, blotting, drying and mass measurement. The standard includes a normative annex describing a conventional oven drying procedure and notes on precision and reproducibility for typical lens sample masses.

General information

• Status: Withdrawn.
• Publication date: September 1997.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 11.040.70 (Ophthalmic equipment / Ophthalmic optics).
• Edition / version: Edition 1 (1997).
• Number of pages: 10 pages.

Key bibliographic details and lifecycle status are recorded on the ISO catalogue entry for ISO 10339:1997.

Scope

Specifies methods to determine the water content of hydrogel contact lenses in their fully hydrated state. The scope covers sample conditioning, recommended test environment, mass measurement and a conventional oven drying (loss‑on‑drying) procedure intended to give comparable water‑content values between laboratories. The standard applies to soft hydrogel lenses and the materials from which they are made.

Key topics and requirements

• Gravimetric determination (loss on drying): weigh hydrated sample, dry to constant mass, calculate water content from mass difference.
• Drying conditions (example from normative annex): laboratory oven maintained at about 105 ± 5 °C for drying (conventional oven method described).
• Sample equilibration: lenses equilibrated in saline at (20 ± 0.5) °C for at least 1 hour prior to testing.
• Blotting procedure: controlled blotting (examples given) to remove surface free solution without causing partial dehydration — technique affects accuracy and repeatability.
• Apparatus and measurement: analytical balance with 0.1 mg resolution, dried glass slides, desiccator with active desiccant and calibrated oven.
• Precision notes: the standard documents limitations in accuracy due to blotting; inter‑laboratory ring tests reported tolerances on the order of tenths of a percent for thicker samples and reproducibility on the order of about 1% for lenses of typical mass.
• References and cross‑references: saline composition referred to ISO 10344 and other relevant ophthalmic optics methods.

Typical use and users

Used by contact lens manufacturers, materials scientists, optical product test laboratories, quality control departments and regulators to verify labelled water content, compare materials, and support product specifications and regulatory submissions. Test houses use the method for batch verification and R&D comparisons; manufacturers use it during formulation and lot release.

Related standards

ISO 10339:1997 has been withdrawn and its subject matter was incorporated into the ISO 18369 series for contact lenses; it was replaced by ISO 18369‑4 (2006) which in turn has later revisions (ISO 18369‑4:2017 and subsequent editions). ISO 10344 is referenced for the saline solution used in conditioning. Users should consult the current part(s) of the ISO 18369 series for the up‑to‑date methods and requirements.

Keywords

water content; hydrogel contact lenses; ophthalmic optics; gravimetric method; loss on drying; oven drying; ISO 10339; ISO 18369; lens testing; saline conditioning.

FAQ

Q: What is this standard?

A: ISO 10339:1997 is an International Standard that specified a laboratory method to determine the water content of hydrogel (soft) contact lenses using gravimetric (loss‑on‑drying) techniques.

Q: What does it cover?

A: It covers sample conditioning (equilibration in saline at ~20 °C), blotting procedures to remove free surface liquid, requirements for balances and ovens, an oven‑drying normative annex (conventional oven at ~105 °C), calculation of water content from mass loss and notes on precision and reproducibility.

Q: Who typically uses it?

A: Contact lens manufacturers, materials and product test laboratories, quality assurance teams, researchers and regulatory bodies involved in ophthalmic optics product evaluation.

Q: Is it current or superseded?

A: ISO 10339:1997 has been withdrawn. Its methods were incorporated into the ISO 18369 series (see ISO 18369‑4:2006 and later revisions); users should refer to the latest edition of ISO 18369‑4 for the current, authoritative test methods.

Q: Is it part of a series?

A: Yes — the topic (physicochemical testing of contact lenses and materials) is now covered by the ISO 18369 series (Ophthalmic optics — Contact lenses), specifically part 4 for physicochemical properties including water content.

Q: What are the key keywords?

A: Water content, hydrogel, contact lens, gravimetric, oven drying, blotting, saline conditioning, ISO 10339, ISO 18369.