Hertel Exophthalmometer (Good-Lite)

Description

The Hertel exophthalmometer is used to measure the degree of eye protrusion (exophthalmus) or recession (enophthalmus). This is particularly important in ophthalmic conditions such as thyroid-related orbitopathy (e.g., Graves’ disease) or after an orbital fracture.

The instrument uses special prisms to determine the position of the cornea in relation to the orbit with high precision. The measurement range is between 0 and 35 mm, and the interpupillary distance can be adjusted from 80 to 120 mm.

Thanks to its robust design and easy readability, the Hertel exophthalmometer is the most widely used method worldwide for reliably assessing eye position and asymmetry.

Hertel Exophthalmometer – Components

• Left and right prisms
• Fixed and movable holder
• Support surfaces on the bony orbital rims
• Supplied with carrying case

With its prism design (isosceles right-angled triangle made of optical glass), the position of the cornea relative to the orbit can be read accurately. The scale runs from 0–35 mm, with red markings at 18 mm to help prevent parallax (distortion).

Instructions for Use

1. Place the fixed holder against the outer orbital rim of the right eye.
2. Slide the movable holder to the outer orbital rim of the left eye.
3. Ask the patient to look straight ahead. When the red lines of the prism overlap, the instrument is correctly positioned.
4. Read the protrusion of the cornea relative to the orbital rim (normal value: approx. 12–14 mm).
5. The distance between the temples corresponds to the interpupillary distance plus the distance to the orbital rims; normally around 100 mm.

Technical Specifications

• Measurement range for protrusion (exophthalmus): 0–35 mm
• Adjustable interpupillary distance: 80–120 mm

Additional Information

Handle the instrument with care; avoid shocks or shaking, as this may reduce measuring accuracy.

Good-Lite number: 521500

Download the official English manual for the Good-Lite exophthalmometer here.