What is it? This is a test to measure the shape and size of the eye. It is commonly used to calculate the power of intraocular lens (IOL) implants required for cataract and refractive surgery. Biometry can be performed using either optical coherence interferometry or ultrasound technology. At the London Eye Hospital we use the… Read More


What is it? Tonometry is the measurement of intraocular pressure (IOP) which is the pressure of fluid within the eyeball. This can be either contact or non-contact depending on the instrument used. At the London Eye Hospital we use the Goldmann & Tonopen contact tonometers. Raised IOP can damage nerve fibres within the eye leading… Read More

Humphrey Visual Fields

What is it? Visual field screening (perimetry) is used to assess your peripheral vision. This is particularly useful in conditions affecting the eye, optic nerve (glaucoma) and brain (tumours). The different visual field tests we offer include: Central 30-2 Central 24-2 Central 10-2 Peripheral 60-4 Macula C-40 Screening C-64 Screening C-76 Screening C-80 Screening Esterman… Read More


What is it? This is the measurement of corneal thickness and is performed using a pachymeter. A thin or thick cornea affect eye pressure measurements – it is therefore always useful to measure the thickness of the cornea when evaluating IOP readings. How is it done? A drop of anaesthetic is placed in the eye… Read More

Fundus Photography

What is it? This is an imaging technique used to take photographs of the retina. This is useful to monitor the progression of conditions such as diabetic retinopathy, macular degeneration and glaucoma. At the London Eye Hospital we use the state of the art Carl Zeiss Visucam 500. This is able to take the following… Read More