First chronic hypotony clinic established at Moorfields Eye Hospital

The world’s first dedicated hypotony clinic, funded by Moorfields Eye Charity, has been established at the Moorfields Eye Hospital, London, according to a press release.

Physicians there reported that treatment of hypotony with hydroxypropyl methylcellulose (HPMC) has resulted in significant visual improvements in their study patients. This treatment replaces the standard of care silicone oil injection. The investigators published their findings in the British Journal of Ophthalmology on January 12.

“We are excited that this simple treatment has proved so effective for patients with this rare condition. This is the start of a process of understanding more about the balance of fluid inside the eye, leading to improved care for our patients,” stated Moorfields consultant ophthalmologist Harry Petrushkin.

Hypotony causes abnormally low intraocular pressure (IOP), that is, less than 6.5 mmHg, that negatively affects the normal shape and internal structure of the eye.

Over time, this can lead to progressive and permanent vision loss, that over several years can cause blindness. Hypotony may develop as a result of underlying eye conditions that damage the part of the eye responsible for producing the fluid that maintains normal eye pressure, according to the press release.

Use of HPMC eliminates the long-term side effects associated with silicone oil that includes toxicity to the ocular structures and obscured vision.

The authors reported, “The data published today indicate that ocular injections containing HPMC, an inexpensive gel used in most eye surgeries, can be used safely to increase the volume of eyes with hypotony, increasing both their size and pressure.”

The success reported in the study was achieved by integrating structured clinical assessment and collaboration with bioengineers at the University College London to understand the drivers of chronic low IOP, the press release explained.

Study outcomes after 12 months of treatment

Seven of the eight patients reported in the publication experienced gains in vision and restored IOP and ocular length over 12 months of treatment with HPMC.

In the study, the presenting best-corrected visual acuities ranged from 0.3 to 1.7 logarithm of the minimum angle of resolution (logMAR) and at the end of the study they ranged from 0.1 to 1.6 logMAR. The presenting IOPs ranged from 1 to 5 mmHg with a median value of 3.5 mmHg. After 12 months the IOPs ranged from 3 to 23 mmHg with a median of 9 mmHg.

The axial length increased in six of the eight study eyes in a range of 0.6 to 2.9 mm; the median value was 1 mm.

Accessing the hypotony clinic

The authors of the study emphasized that if patients have low IOP that may result from a pre-existing eye condition, and they have vision in the affected eye, they should ask their consultant to refer them to Moorfields; this is the only way to access the hypotony clinic, according to the press release.

“This preliminary data are already informing thinking on standardised hypotony treatment nationally. It provides a foundation for future, larger-scale formal clinical trials to evaluate the potential of this highly promising approach,” the investigators commented.

Additional information about the hypotony clinic is available at moorfields.pressoffice@nhs.net