Clinical Trial Details
— Status: Not yet recruiting
Administrative data
| NCT number |
NCT05506553 |
| Other study ID # |
311123 |
| Secondary ID |
|
| Status |
Not yet recruiting |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
September 2022 |
| Est. completion date |
September 2024 |
Study information
| Verified date |
July 2022 |
| Source |
Guy's and St Thomas' NHS Foundation Trust |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
In an aging population, cataract and presbyopia become increasingly common. A cataract is the
opacification of the natural crystalline lens inside a person's eye, causing reduction of
vision. Presbyopia is an age related condition resulting in loss of reading/near vision which
results in requiring reading glasses.
Astigmatism is a common condition characterized by an abnormal cornea (the clear tissue at
the front of the eye) which results in blurred distance and near vision, again requiring
glasses.
Cataract surgery is the most common elective surgery worldwide for patients over 65. It is
composed of removal the cataract and insertion of a new intraocular lens (IOL). Currently
only monofocal IOLs are available on the National Health Service (United Kingdom) - meaning
they give good distance or near vision. The majority of patients opt for good distance vision
with glasses to read.
The investigators are trialling insertion of a new Extended Depth of Focus (enhanced
aspheric) Toric IOL (EDoF Toric IOL), which treats all 3 conditions - cataract, presbyopia
and astigmatism. All patients attending St Thomas' hospital for treatment of cataracts, who
have presbyopia and astigmatism will be considered for invitation to the study.
Patients who participate in the study will be randomly selected to receive either the new IOL
- the TECNIS Eyhance Toric II IOL, or a well-established IOL the Alcon Acrysof IQ Toric IOL
during cataract surgery. Insertion of the Alcon Acrysof IQ Toric IOL is known to treat
cataract and astigmatism but not presbyopia.
Patients will be assessed and have their surgery performed at St Thomas' Hospital London.
They will have 7 appointments over 12 months, plus surgery. The investigators hope to
demonstrate better distance, intermediate and near vision and increased spectacle
independence in the TECNIS Eyhance Toric II IOL group.
EDoF Toric IOLs have the potential to transform cataract surgery outcomes for patients in the
NHS.
Description:
Cataract is a condition caused by progressive clouding of the natural crystalline lens inside
the eye. This leads to impairment of visual performance. This condition represents a huge
disease burden and is a leading cause of reversible blindness worldwide. In the UK and the
developed world, the incidence of cataract induced blindness continues to increase, secondary
to an aging population and increasingly common risk factors such as diabetes. In 1950, Harold
Ridley inserted an intraocular lens following cataract extraction at St Thomas' Hospital.
This was the first recorded surgery of its kind, and heralded the development of modern
cataract surgery, which is comprised of extraction of a cataract by phacoemulsification
(ultrasonic micro-fragmentation) followed by insertion of a foldable intraocular lens.
Cataract surgery (CS) is the most common elective surgical procedure in the developed world,
and the most common in the EU, with 4 million procedures performed in 2016. CS continues to
evolve, as do intraocular lenses (IOLs).
Currently, only mono-focal (one point of focus) IOLs are available during cataract surgery in
the NHS. These are designed to give excellent vision for one fixed point of focus (either
distance, intermediate or near vision), with most patients opting for good distance vision,
and requiring glasses for intermediate vision or near vision. Accordingly, these lenses do
not treat presbyopia, the loss of the ability focus on near objects, that most people develop
in their 50's. In addition, the standard monofocal lens does not treat astigmatism, a common
condition characterized by a non-spherically shaped cornea (the clear tissue at the front of
the eye) which results in blurred unaided distance and near vision and the need for both
reading and distance glasses following surgery.
In this trial patients will be randomly assigned to receive two TECNIS Eyhance Toric lenses
or two Alcon Acrysof IQ Toric II lenses (one for each eye). Prior to surgery the 'power' of
each patients intraocular lens is chosen. This is similar to choosing the power of lenses in
spectacles at an opticians. By choosing the power of one eye to be targeted for distance and
the other offset for a small myopic (short-sighted) correction to allow unaided intermediate
(computer) and some unaided near vision, the investigators can then investigate the efficacy
of these lenses not only to improve vision after cataract surgery but also their ability to
treat astigmatism and reduce the dependence on spectacles following NHS CS. As such the
investigators hope to offer cost benefits to NHS patients as well as quality of life
improvements. In addition to efficacy, quality of life and cost benefits to patients, the
investigators will also explore patient acceptability of such "premium" IOLs and look at
models to investigate their affordability with the NHS setting.
This study is a clinical trial, designed to compare visual outcomes after cataract surgery
with two different intraocular lenses. As previously described, modern day cataract surgery
is composed of two main components: removal of the cataract, and insertion of an intraocular
lens (IOL). The role of the intraocular lens is to replace the focusing power of the natural
crystalline lens inside the eye. It is this lens that becomes a cataract. Removing a cataract
alone helps light enter the eye, but does not focus it well. Prior to the invention of
intraocular lenses, patients required extremely thick and strong glasses for both distance
vision.
Currently only monofocal intraocular lenses are available on the NHS. Different strengths of
lens can be chosen to give the patient good distance, intermediate or near vision. That means
the ability to focus on objects in the distance, middle distance or near. Most patients opt
for good distance vision, enabling them to mobilise easily, watch TV and drive, and require
glasses for reading.
As described above, most patients over the age of 50, have some element of presbyopia, which
is the inability to focus on near objects, resulting in the need for reading glasses.
Inserting extended depth of focus (EDoF IOLs) intraocular lenses during cataract surgery, can
help improve their reading vision without reading glasses.
Astigmatism is an abnormality of the cornea, which requires special distance and reading
glasses to give clear distance and near vision. Toric IOLs correct astigmatism and reduce or
prevent the need for astigmatism correcting glasses after surgery.
The TECNIS Eyhance Toric II IOL is a new IOL which corrects astigmatism and has an enhanced
depth of focus through its novel 'enhanced aspheric' design. This will help treat presbyopia.
The Alcon Acrysof IQ Toric IOL is an established Toric IOL corrects astigmatism alone.
This trial will investigate the effect of a new Extended depth of focus (enhanced aspheric)
toric lens on vision and compare it to a commonly used Toric IOL. The investigators will
recruit patients who have bilateral cataracts with astigmatism. These patients will have
otherwise healthy eyes. Patients who have been referred to St Thomas' Hospital for assessment
for cataracts will be considered for the trial. If they fulfil the criteria for acceptance to
the trial, the consulting doctor will discuss this with the patient. If the patient expresses
interest, they will be referred to the Research department. The cataract research fellow will
review them and consider them for admission to the trial. This review will happen on the day
of the original appointment, or the patient will be given an another appointment time and
date for further assessment. If a patient would like further information about the study, but
cannot speak to the Cataract Research Fellow that same day, they will be asked to fill in a
Consent to Contact form, which will allow the research department to contact the patient for
consideration for entry to the study.
The investigators will recruit 2 groups of patients, with 70 patients in each group. The
investigators will randomly assign them to either the TECNIS Eyhance Toric II group or the
Alcon Acrysof IQ Toric IOL group. All patients will cataract surgery on one eye, appointments
to review their progress, and then the second cataract operation. The patients in the TECNIS
Eyhance group will have TECNIS Eyhance Toric II lenses inserted into both eyes. The patients
in the Alcon Acrysof IQ Toric group will have Alcon Acrysof Toric IQ lenses inserted into
both eyes. Patients who fulfil the inclusion/exclusion criteria will be fully informed of the
investigative nature of the study and consented. Neither the TECNIS Eyhance Toric II IOL or
the Alcon Acrysof IQ Toric IOL are used in the NHS, but are used in private practice in the
UK
Once patients are consented, they will have a pre-operative assessment which will include a
full eye examination (including biomicroscopy and tonometry), refraction (a glasses similar
to a visit to an opticians), have their vision tested at near, intermediate and distance with
and without glasses. They will also have contrast sensitivity (previously described),
pentacam scanning (mapping of the front of the eye) and an intraocular pressure check. The
investigators will perform a biometry (measurement of the eye) to calculate the lens power
required for surgery. Intraocular lenses are available in different powers, in the same way
spectacle lenses are available in different powers.
Cataract surgery will be performed during National Health Service (United Kingdom) cataract
lists at St Thomas' Hospital. Surgery will be performed by senior cataract surgeons, and
standard protocols will be followed. Patients will be reviewed at 2 weeks, 6 weeks and 6
months after surgery.
The 2 weeks post operative review will be collect the same data as the pre-operative
assessment as described above. Patients reviewed at 6 week and 6 months post operation will
have all of the above, plus digital imaging (photography), stereoacuity (3d vision) and
ScheimpflugTomography (3d scanning) to assess IOL tilt and decentration. The digital
photography will be compared with a digital photograph taken on the day of surgery, to assess
rotational lens stability. The 6 month digital image will be used to assess posterior
capsular opacification and glistenings (problems with the lens or behind the lens).
Anonymised digital images may be shared with Prof Chris Hull at City University to help us
assess glistening of the IOLs. At pre-operative assessment and 6 week assessment a scan of
the macula (macula OCT) will take place. This is a noninvasive test done in the eye
department.
Participants in the study at the 6 weeks-, 6-month visits should expect to take around an
extra 120 minutes in total for these extra, non-invasive tests to be performed. Patients will
be asked to complete questionnaires, namely EQ-5D-3L, Catquest-9SF and Cat-PROM, before
surgery- and at 6 week and 6 months post-operatively. At 6 months, the need for, type of and
expenditure cost of spectacles required by patients will be recorded and compared between
groups. Finally patients will be monitored for adverse events at every appointment after
surgery.
Interim data will be reviewed at 20% completion of treatment and 6 month followup (following
second eye surgery). The study completion date will be when Patient 140 has completed their 6
month visit (following second eye surgery) plus 14 days for data entry and database lock.
The investigators will be using a strategy called micro-monovision. Most people have a
dominant eye, in the same way that they have a dominant hand. In micro-monovision the
investigators choose an intraocular lens power that will give the dominant eye good distance
vision (emmetropia), and a intraocular lens power that will give the non-dominant eye good
intermediate distance vision. The investigators will be using this strategy in both the
TECNIS Eyhance Toric II group and the Alcon IQ Toric group.
The investigators are testing the following hypotheses (theories)
1. That the TECNIS Eyhance Toric IOL, when implanted in both eyes, will give better middle
distance and near vision, than the Alcon IQ Toric lens, whilst maintaining a similarly
good quality of good distance vision. The investigators will also compare contrast
sensitivity and stereoacuity (described previously). The investigators will also record
complaints of 'flashing lights' or 'halos' in a patients vision, which can be caused by
the implantation of the intraocular lens. These are considered to be a rare side effect.
2. That the TECNIS Eyhance Toric II IOL, when implanted in both eyes, will give better
middle distance and near vision, than the Alcon Acrysof IQ Toric lens, resulting in
improved patient satisfaction scores on the CatPROM and CatQUEST trial.
3. That the TECNIS Eyhance Toric II IOL, when implanted in both eyes, will give better
middle distance and near vision, than the Alcon Acrysof IQ Toric lens, thus resulting in
reduced costs for the patient, as they will not need to buy reading or intermediate
vision glasses.
4. That the TECNIS Eyhance Toric II IOL, when implanted in both eyes, will give better
middle distance and near vision, than the Alcon Acrysof IQ Toric lens, has similar
stability, and does not rotate.
