Amblyopia originates from abnormal early binocular visual experience due to strabismus, anisometropia or form deprivation in young childhood and is accompanied by the loss or severe impairment of binocular depth perception.

 In this condition, the corrected visual acuity of the suppressed eye suffers a reduction as a consequence of the associated visual cortex changes, even though no visible abnormalities are present.

The worldwide prevalence of amblyopia is between 1 and 5%

 and is approximately three times higher in an unscreened population compared with a screened cohort.

 Unrecognised amblyopia can lead to various functional deficits of the visual system that become more difficult to treat with increasing age.

 Accordingly, there is an evident need for a reliable screening method for the condition, which also needs to be easy to perform and fast considering that it is largely needed for young children.

Since a deficit of the binocular visual function is present in amblyopia, the use of stereo vision tests has been proposed as potentially useful for amblyopia screening.

 However, most of the conventional stereopsis tests available on the market contain monocular cues for various reasons,

 and so can lead to inaccurate stereoacuity values. 

Likewise, all tests have a predetermined set of stimuli displayed on a plastic or paper board which encourages motivated children to memorise expected responses. In school or kindergarten screenings, biased results can be obtained if children have an opportunity to communicate with their friends after the evaluation.

These factors have been demonstrated to affect the ratio of both the false-positive and false-negative passes.

 Stereotest disadvantages such as these create the need for more versatile tools using new technologies to be developed(e.g., tablets and smartphones) to facilitate their use.


A new screening system called EuvisionTab has been developed by the University of Pécs, Hungary, and comprises software that can be used on Android devices, overcoming most of the limitations of currently available stereotests.

 Part of the system is a stereovision module, based on a random dot stereogram (RDS), which is essentially an RDS image generator with great flexibility as the parameters of the RDSs are freely adjustable (Figure 1).

It also includes a dynamic version of the RDS, which had an embedded, disparity-defined Snellen-E optotype (DRDSE) that is presented in random orientations (up, down, left or right). The orientation ofthe ‘E’ is only visible if the images are perceived binocularly through red-green anaglyph glasses (low-pass red R26 and YG09 band-pass green gelatin filters)

The first version screening set of Euvision comprises a series of nine binocularly visible Snellen E letters and two monocularly visible Snellen-Es. The latter two serve as control, to check if the subjects have really understood the task and are able to identify the Snellen E orientation regardless of the existing ocular condition.

The disparity and the dot size of the images are 420 sec of arc, which is the lowest within the optimum range.

 The line thickness of the Snellen E optotype subtends 2° of visual angle from the 25–30 cm viewing distance.

The dot density of the images is 1%, with 3% uncorrelated noise. Images are updated at 10 Hz. Before the presentation of the nine + two DRDSE, eight other, easier-to-practice RDS images are shown to enable the user to become familiar with the task and the stimuli. These RDS images arecomposed of either static (non-refreshing) dots, or they have larger disparities and a higher dot density.

Euvision is under constant development, with regular clinical validation of the newer screening sets taking place. Once the product is commercialised, its users will always be provided with the upgrade of the most efficient state-of-the-art vision screening methods.

The screening system can also be used to perform a remote examination by using different video conference programmes (e.g., Skype, Zoom, Microsoft Teams, Cisco Webex, etc.) The only requirement is that the anaglyphic glasses should be passed to the patient prior to the date of examination.

After sharing the examination screen, the stereo vision test can be conveniently carried out with the video guidance of the examiner. Limitation of the frame rate in dynamic RDSs can occur due to insufficient internet bandwidth but static RDS can be applied with no problems.


A clinical study was conducted with the Euvision system at the Department of Ophthalmology of the University of Pécs to define its sensitivity and specificity for amblyopia detection and also for the detection of other visual conditions.13 Specifically, our DRDSE test (presented on version 10.1 of a Samsung Galaxy tablet) was compared with the Lang II stereotest in a sample of 141 children (aged 4–14 years; mean age 8.9).

In this series, DRDSE was found to have better sensitivity than Lang II for the detection of amblyopia (100% versus 81.8%), convergent strabismus (100% versus 80.9%) and uncorrected (75% versus 52.8%). The specificity of DRDSE was 61.2%, 67.3% and 68.6% for amblyopia, strabismus and hyperopia, respectively, whereas these values were somewhat better for Lang II (73.8%, 79.2% and 77.9%, respectively).

Significant improvements were introduced in the EuvisionTab system before a second clinical trial took place. Now, the frame rate can be precisely maintained constantly regardless of the type of hardware used; it can be adjusted between 1 and 60 Hz. The dot arrangement became insensitive to the quality of anaglyphic filters, and no monocular cues are visible even if commercial paper glasses are used.


The second clinical study was conducted at the Department of Ophthalmology of the Vithas Medimar Hospital, Alicante, Spain, in 473 children (aged 4–14 years). Good sensitivity and specificity for the detection of amblyopia were obtained using different dot density and pass/fail criterion for the DRDSE test in this larger sample (100% and 81%).

With the Lang II system, sensitivity was only 48.4%, with a specificity of 98%. More detailed results of the study will be published soon.


The DRDSE test with the latest improvements in dot density and pass/fail criteria is a valuable tool for amblyopia screening and gives a better performance than other tests considered as the gold standard for screening. The test is very sensitive and specific enough for the detection of amblyopia in children.

The main advantages are that the test is performed in only 5 min (including the explanation of the task to the children) and is easy to use (after a short amount of training) for non-professional examiners such as teachers, parents, district nurses or social workers. As for the technical requirements, a tablet or mobile phone with the appropriate software and red-green spectacles are required.

More studies are being conducted to evaluate the recent improvements that have been made to the test in large samples as well as to analyse its diagnostic performance for other visual conditions.

Admed Harmouche, MD
András Czigler, MD
Gábor Jandó, MD, PhD
László Závori, MD, FRCEM, MSc
István Szabó, MD, PhD
Eszter Mikó-Baráth, MD, PhD
David Piñero, PhD
E: david.pinyero@gcloud.ua.e

Prof. Jandó, Dr Czigler, Dr Harmouche, Prof. Szabó and Dr Závori are based at the University of Pécs Medical School in Pécs, Hungary and are also software/ computer engineers at Euvision Ltd. Prof. Mikó-Baráth is based at the University of Pécs Medical School. Prof. Piñero is based at the Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain. Prof. Jandó is CEO of Euvision; none of the other authors have any financial interests.

McKee SP, Levi DM, Movshon JA. The pattern of visual deficits in amblyopia. 

Webber AL, Wood J. Amblyopia: prevalence, natural history, functional effects and treatment. 

Polling JR, Loudon SE, Klaver CC. Prevalence of amblyopia and refractive errors in an unscreened population of children. 

Hernández-Rodríguez CJ, Piñero DP. Active vision therapy for anisometropic amblyopia in children: a systematic review. 

Julesz B, Kropfl W, Petrig B. Large evoked potentials to dynamic random-dot correlograms and stereograms permit quick determination of stereopsis. 

Simons K, Moss A. A dynamic random dot stereogram-based system for strabismus and amblyopia screening of infants and young children. 

Ehrlich MI, Reinecke RD, Simons K. Preschool vision screening for amblyopia and strabismus. Programs, methods, guidelines, 1983. 

Newman DK, Hitchcock A, McCarthy H, Keast-Butler J, Moore AT. Preschool vision screening: outcome of children referred to the hospital eye service. 

Hahn E, Comstock D, Durling S, et al. Monocular clues in seven stereotests. 

Serrano-Pedraza I, Vancleef K, Read JC. Avoiding monocular artifacts in clinical stereotests presented on column-interleaved digital stereoscopic displays. 

Farvardin M, Afarid M. Evaluation of stereotests for screening of amblyopia. 

Budai A, Czigler A, Mikó-Baráth E, et al. Validation of dynamic random dot stereotests in pediatric vision screening. 

Markó K, Kiss HJ, Mikó-Baráth E, et al. Contrast independence of dynamic random dot correlogram evoked VEP amplitude. 

Horvath G, Nemes VA, Rado J, et al. Simple reaction times to cyclopean stimuli reveal that thebinocular system is tuned to react faster to near than to far objects.

https://doi.org/10.1371/journal.pone.0188895

Articles

A new amblyopia screening system that can be used on Android devices has performed better than some of the ‘gold standard’ stereotests in recent Hungarian studies.

Amblyopia screening with the dynamic random dot stereotest

Compared with traditional spectral domain optical coherence tomography (SD-OCT), swept-source OCT (SS-OCT) allows us to image the eye’s deep tissues with excellent fidelity and consistency. The technology’s rapid scanning speed and targeted wavelength helps us to visualise the choroid and sclera in remarkable detail, and enables us to acquire 6, 9 and 12 mm scans in a fast and efficient manner.

Recently, we collaborated to investigate the use of SS-OCT and in particular, swept source OCT angiography (SS-OCTA*) to differentiate between a range of intraocular tumours. Over the course of our study, we used our imaging platform (DRI OCT Triton, Topcon Medical Systems) to capture detailed images that helped us to find evidence-supported diagnoses and treatment plans.

In our prospective study, we evaluated 40 intraocular tumours, including 16 choroidal nevi, ten melanomas, six choroidal hemangiomas, three choroidal metastasis, three retinal haemangioblastomas and two melanocytomas. All patients enrolled in the study underwent a complete ophthalmic evaluation including ultrasound, SS-OCTA and fluorescein angiography. To help the reader to better understand the value of swept source technology, we are pleased to share case details and images.

For choroidal nevi, we typically found a dome-shaped lesion associated with choriocapillaris compression and choroidal shadowing. In a representative case (Figure 1A-C), we encountered retinal pigment epithelium (RPE) irregularities which indicated the presence of drusen, thus demonstrating the chronicity of these lesions (Figure 1B and C). We also see marked photoreceptor loss (Figure 1C). OCTA analysis shows a more hyperreflective ring than the centre of the lesion in the superficial capillary plexus map (Figure 1A).

This is supported by corresponding fundus photography (Figure 1B). Both images, as well as additional visualisations, are produced by the SS-OCTA platform in very little time.

For choroidal melanoma, however, differences emerge. In this case (Figure 2A-D), we identified a dome-shaped lesion in addition to compression of the choriocapillaris. There is still choroidal shadowing, but these lesions also typically present intraretinal oedema, shaggy photoreceptors, loss of photoreceptors and subretinal fluid (Figure 2D).

OCTA demonstrates that these conditions present observable artefacts because the subretinal fluid is present (Figure 2A and B). We are currently investigating additional cases to try to correlate these patterns with tumour growth and possibly, metastasis. Hyperreflectivity and vascular patterns can likely be correlated with prognosis, but more confirmatory research is needed.

For choroidal haemangiomas (Figure 3A-D), we often observed a dome-shaped lesion associated with chronic RPE and cystic changes. There is no compression of the choriocapillaris. We also see dilated choroidal vessels, a hallmark in structural OCT visualisation (Figure 3A) given the large vessels that correlate with histopathology.

In this example, we see that OCTA (Figure 3C-D) shows a hyper-reflectivity of vessels. However, the areas lacking observable flow could also represent large vessels with slow flow. After treatment, the pattern of hyperreflectivity decreases in the periphery.

 In some patients, certain vessels can be detected in the central retina.

Choroidal metastasis (Figure 4A-C) is another type of lesion SS-OCT can help differentiate. It presents as a lumpy, bumpy, contour-like lesion, often with granular changes of the RPE.1 There are empty spaces between the neurosensory retina and RPE. Additionally, there is tumour-infiltrated choroid, as well as hyperreflective points/dots in the external retina on the tumour.

The example in Figure 4 shows the metastatic lesion (Figure 4A) and hyperreflective pinpoint lesions on the retina (Figure 4B) with a bumpy appearance and visible subretinal fluid (Figure 4C). When patients like these are treated (with systemic chemotherapy), we see better visibility of the choroidal vessels because of RPE atrophy. After the treatment, large choroidal vessels become apparent on OCT-A (Figure 4D; shown here from another patient).

A melanocytoma is a bilobular mass with highly pigmented choroidal vessels protruding through the lamina cribrosa.

 These tumours are often characterised by posterior shadowing, as well as cystic changes between the normal retina and melanocytoma lesion (Figure 5AD). The lesions typically appear with hyperreflectivity of the tumour’s vessels on the surface.

OCTA images (Figure 5A-B) show that the diameter of the tumour can be delineated (see yellow colouring), whilst the violet colouring shows the areas in which flow of the lesion is detected both in the retinal superficial and deep plexus. OCTA images (Figure 5A-B) show relative hyporeflectivity of the lesion, but there are some superficial vessels that can be seen here as well. We monitor these vessels for potential malignant transformation.

A haemangioblastoma is generally an exophytic mass protruding from the internal retina. There is exudation and large vessels from the optic disc can extend to the periphery, which are the classical feeder vessels (Figure 6A-E). There are hyperreflective dots on the external layers of the retina that correspond to exudation (Figure 6A-B).

The posterior hyaloid seems to be, in most of the cases, very strongly attached, creating traction in these vascular tumours; this traction and exudation can decrease after treatment and after posterior vitreous detachment (Figure 6A-B). Figure 6D depicts OCTA, demonstrating the feeder vessels and alterations of foveal avascular zone in the superficial and deep vascular plexus after treatment.

Ultimately, SS-OCT provides clinicians a clear view on internal structures and abnormalities, allowing us to measure and compare with confidence. In a way, SS-OCT functions like an optical biopsy of intraocular tumours, helping us differentiate between benign and malignant lesions. In the future, SS-OCT, particularly with OCTA functionality, could play an important role in helping to differentiate, diagnose, prognosticate and manage intraocular tumours.

Dr Arevalo is the Edmund F. and Virginia B. Ball professor of ophthalmology and chairman at the Department of Ophthalmology, Johns Hopkins Bayview Medical Center, Wilmer Eye Institute, and at the Johns Hopkins University School of Medicine in Baltimore, Maryland, United States. He has received grant research funds from Topcon.

Dr Arias is associate professor of Retina & Vitreous/Oncology at the Universidad Autónoma de Bucaramanga, Foscal Internacional Floridablanca, Santander, Colombia. He has no financial disclosures.

Cennamo G, Romano MR, Breve MA, Velotti N, Reibaldi M, de Crecchio G, Cennamo G. Evaluation of choroidal tumors with optical coherence tomography: enhanced depth imaging and OCT-angiography features. 

*Topcon OCTA technology is not cleared for sale in the United States.

SS-OCT provides a clear view of the eye’s internal structures and any abnormalities, helping to differentiate benign from malignant lesions. 

Using swept-source OCT and OCT angiography to image choroidal tumours 

Gonioscopy forms an essential part of the glaucoma evaluation, enabling the structure of the iridocorneal angle to be seen, which is important in diagnosing and monitoring eye conditions associated with glaucoma. However, Schlemm’s canal (SC) can be poorly visible in the angle, especially in excessively pigmented eyes.

Blood reflux from episcleral veins to the SC is a well-known sign that helps one to visualise the SC

 and can be caused by the pressure of the goniolens on the episcleral veins, reduced intraocular pressure (IOP) or both.

 Three quarters of outflow resistance of the aqueous humour in normal eyes comes from the trabecular meshwork (TM), while 25% of the resistance comes from SC.

 The juxtacanalicular meshwork is responsible for normal outflow resistance in the TM.

Many glaucoma surgeries aim to overcome this resistance of outflow, which may reduce the IOP. The trabecular micro-bypass implant iStent inject (Glaukos Corporation), which received CE Mark clearance in Europe in 2010 for the treatment of open-angle glaucoma,

 aims to connect the anterior chamber directly with SC, thus overcoming the resistance of the TM.

In one study, blood reflux was seen in nearly all (91%) of eyes immediately after implanting iStent,

 but there are few case reports about the late hyphaema that can occur through the implant following surgery.

 We evaluated blood reflux during gonioscopy 3 to 6 months following implantation of either the trabecular micro-bypass devices iStent inject or the newer-generation device, iStent Inject W, to evaluate the effectiveness of the implantation and adjust the drugs therapies patients were on if necessary.

In a case series, 22 eyes from 20 patients who had been diagnosed with either early primary open-angle glaucoma (POAG) or ocular hypertension (OHT), and who also had cataracts and prior difficulties with eyedrops, received implants of either iStent inject or iStent inject W combined with their cataract surgeries. All procedures were carried out by the same surgeon at the department of ophthalmology in Staedisches Klinikum Dresden hospital in Dresden, Germany.

Two stents were implanted in each eye nasally. 14 eyes received iStent inject and eight eyes were implanted with iStent inject W. Patients were treated with at least one hypotensive eye drop before the surgery.

The patients were controlled regularly after the surgery and the IOP was measured at each visit. The required drugs therapy was reduced in most cases and adjusted to reach the target pressure according to the guidelines of European Glaucoma Society, with consideration of the IOP before the surgery.

There were no significant complications intraoperatively or after the surgery. Gonioscopies with Goldmann 3 mirror classic contact lens 903 was performed on the eyes 3-6 months after surgery to evaluate the blood reflux through the devices.

The gonioscopy lasted about 1 minute with light pressure applied to the lens and slightly greater pressure applied nasally, before the pressure was eased off and evidence sought of possible blood reflux from the lumina of either of the stents.

Following the surgeries, patients had a mean IOP of 18 mmHg and a mean of 1.25 glaucoma eye drops was used. The patients did not require any further interventions and there were no complications observed intraoperatively or postoperatively.

Three of the patients who had an IOP of less than 15 mmHg had blood reflux through one of the two iStents during gonioscopy, but this was not visible in the other 19 eyes.

An 82-year-old woman with POAG had an IOP of 13 mm Hg. She was prescribed brinzolamide (Azopt, Alcon Laboratories) eyedrops with a dosing schedule of twice a day.

Gonioscopy was performed 3 months following the surgery. The iStent inject w was implanted. The results can be seen in Figure 1.

An 85-year-old male with POAG had an IOP of 12 mmHg. He was provided with derzolamide plus timolol eyedrops (Cosopt, Merck & Co) for twice-daily use.

A gonioscopy was performed 5.5 months after the surgery. iStent inject was implanted (see Figure 2).

A 72-year-old male with POAG had an IOP of 15 mmHg. He was prescribed tafluprost (Taflotan, Santen Pharmaceutical) eyedrops to be taken once a day.

Gonioscopy was performed 3.5 months following his surgery. iStent inject W was implanted. Results can be seen in Figure 3.

From the findings of these three cases, we can see that all the patients who had late blood reflux had an IOP under 15 mmHg, whereas other patients with higher IOPs did not. It is well known that the IOP following iStent implantation should not be lower than the pressure in the episcleral veins, which is usually 6-9 mmHg, but it can be elevated in glaucoma patients.

Moreover, it is widely accepted that blood reflux in SC is more likely to occur in eyes with low IOP2 since lowering the IOP reportedly facilitates blood movement into SC.

The blood reflux has been classified into three patterns:

No filling, suggesting the collapse of SC and atrophy of collector channels;

Patchy filling of SC suggesting the partial collapse of SC; and

Full filling of SC with blood indicating patent SC and healthy collector channels.

It is important to note that the diameter of SC is between 50.8 μm and 393.5 μm,

 and this diameter is smaller in older patients in comparison with children. Moreover, the diameter of SC is smaller in glaucoma patients compared with those who do not have glaucoma.

We know that the central outlet in iStent inject and iStent inject W is 80 μm and that the side flow outlet is 50 μm. This may lead to the ineffective implantation of the device in some cases, such as where the diameter of SC is small, which may obstruct the outflow.

This could be the explanation for observing blood reflux just from one stent in our three patients and not in both stents, but it could also be related to the IOP and the amount of blood in SC. These considerations may also explain the minimal blood reflux seen in the third patient, which does not obscure the vision of the angle.

On the other hand, the excessive treatment of IOP in glaucoma patients following implantation of the stent may lead to a spontaneous recurrent microhyphaema in the anterior chamber. In these patients, reducing the therapy would be more reasonable and IOP phasing may offer a better view to optimise it. 

In conclusion, gonioscopy may offer a cost-effective method of evaluating the function of iStent after implanting it and could help in adjusting the therapy after the surgery.

---
Abdelwahhab Azzawi, MD, FEBO, MRCPS (Glasg)


E: Abdelwahhab.Azzawi@klinikum-dresden.de


Dr Azzawi is an ophthalmic consultant based at Department of Ophthalmology, 

Staedtisches Klinikum Dresden, Dresden, Germany

Schirmer KE. Gonioscopic assessment of blood in Schlemm's canal. Correlation with glaucoma tests. Arch Ophthalmol. 1971;85:263-267.

Kanski’s Clinical Ophthalmology: A systemic approach. Eighth edition. 2016 Elsevier.

Bill A, Svedbergh B. Scanning electron microscopic studies of the trabecular meshwork and the canal of Schlemm – an attempt to localize the main resistance to outflow of aqueous humor in man. Acta Ophthalmol (Copenh). 1972;50:295-320.

Pillunat LE, Erb C, Junemann AG, Kimmich, F. Micro-invasive glaucoma surgery (MIGS): A review of surgical procedures using stents. Clin Ophthalmol. 2017;11:1583-1600.

Popovic M, Campos-Moller X, Saheb H, et al. Efficacy and adverse event profile of the iStent and iStent inject trabecular micro-bypass for open-angle glaucoma: A meta-analysis. J Curr Glaucoma Pract. 2018;12:67-84.

Fernandes Resende A, Patel NS, Waisbourd M, Katz LJ. iStent trabecular microbypass stent: An update. J Ophthalmol. 2016;2731856.

S Sandhu, Arora S, Edwards MC. A case of delayed-onset recurrent hyphema after iStent surgery. Can J Ophthalmol. 2016;51:e165–e167.

Steven Safran, iStumped over iStent. ASCRS EyeWorld. Feb 2016.

Grieshaber MC, Pienaar A, Olivier J, Stegmann R. Clinical evaluation of the aqueous outflow system in primary open-angle glaucoma for canaloplasty. Investigative Ophthalmology & Visual Science. 2010;Vol.51:1498-1504. doi:https://doi.org/10.1167/iovs.09-4327.

Chen Z, Sun J, Li M, et al. Effect of age on the morphologies of the human Schlemm’s canal and trabecular meshwork measured with swept-source optical coherence tomography. Eye. 2018;32: 1621-1628.


Gonioscopy may offer a reasonable and cost-effective method to evaluate the function of the trabecular micro-bypass device post-implantation and it could help in adjusting the therapy after the surgery.

Monitoring blood reflux during gonioscopy in glaucoma 

The coronavirus pandemic has triggered a seismic shift in the way ophthalmologists interact with their patients, forcing them to think on their feet and find ways to quickly adapt their workflows. 

However, as the crisis continues, it is becoming apparent that some of the changes they have had to make, such as increasingly opting for virtual consultations, could become more permanent, as evidence of their benefits to doctors and patients alike starts to mount. 

Arguably, the pandemic has paved the way for greater opportunities for positive change within ophthalmology and indeed, in healthcare in general.

I asked Prof. Mariya Moosajee, consultant ophthalmic surgeon and clinical academic ophthalmologist at Moorfields Eye Hospital, London, how her working life has changed and how those who specialise in providing services for genetic eye disorders can continue to provide the best care for their patients both during the pandemic and beyond.

Prof. Moosajee’s speciality is genetic eye disease, so the majority of her patients have been deemed non-urgent during the pandemic. 

A lot of such patients across the UK have seen their appointments cancelled, but Prof. Moosajee decided to consult all her patients virtually from the start of the crisis.

How have you had to adapt your workplace during the pandemic?

I have been able to work from home and consulted patients either by telephone or using ‘NHS attend anywhere,’ a secure web-based platform for patients with pre-arranged video consultation appointments, that was nationally funded by National Health Service (NHS) England and NHS Improvement to support NHS trusts and foundation trusts in their response to the COVID-19 outbreak.

I hold my clinics at the same time as they would have been held pre-COVID-19 and allocate patients to my team. I then meet with my colleagues at the end of every clinic on Microsoft Teams so that they can present each case.

We discuss the patients’ future management as a multidisciplinary team; we have a family support officer; a developmental paediatrician; a genetic counsellor; an extended role orthoptist; a low vision optometrist and a paediatric ophthalmology fellow. If we feel our patients need a low vision assessment or specific paediatric input (as a vast number of genetic eye disease patients have systemic features), then the relevant personnel will follow up the patient with a further phone call. It has worked really well; we have consulted 220 patients in total: 150 children and 70 adults with genetic eye disease.

We are restarting face-to-face clinics in the next month. At that stage we will have prioritised patients that will need to come in for clinical assessment and to give blood samples for genetic testing.

Adults who have had recent ophthalmology assessments locally or in other services at Moorfields can be sent blood packs which enables them to take their own blood without having to travel into London and send the sample back to us so we can process it for genetic testing. In fact, the whole process can be undertaken remotely.

What are your views on virtual consultations?

I have been pushing for virtual consultations in genetics for a long time. Prior to COVID-19 (last April–June 2019), we undertook a patient-reported survey with just over 100 paediatric or adult participants, who were either new or follow-up patients, to ascertain their views on virtual consultations and their acceptability.

We found that over 65% percent of participants prefer to have their investigations carried out locally, followed by a virtual consultation with specialists at Moorfields Eye Hospital for the review of these results. Adult participants favour video calls, with contact via the telephone being the least popular response.

The opposite is true for parents and guardians of children, who prefer contact via telephone over video call. There was no difference between the views of new or follow-up patients. Interestingly, despite most patients preferring virtual contact, the majority do not want to be seen virtually for every appointment until a treatment or trial becomes available.

What innovations do you think might be needed in the future?

I do not think we can go back to the way we were working. We can greatly increase our efficiency and patient experience by a combination of virtual and face-to-face consultations.

Patients do not want to wait for hours to have imaging and see a consultant, but they definitely want to see specialists who know about their rare genetic eye condition and who can assess the results of investigations undertaken locally, as well as inform them of the latest research and trials.

The long, detailed records we take in genetics on the onset and progression of symptoms, and prenatal, birth and family history can all be undertaken virtually. Genetic counselling is also a lengthy process that involves an unrushed conversation to ensure patient understanding of the complex topic of inheritance and genetic mutations, informed consent and family planning.

Studies in cardiac and oncogenetics in the Netherlands showed high levels of patient satisfaction for those receiving virtual genetic counselling. I would strongly recommend Telegenetics moving forwards.

In the UK, genomic medicine services are being introduced across all medical specialities, funding for genetic testing is becoming centralised and whole genome sequencing will soon be available to most patients on the NHS. We are trying to encourage more ophthalmologists around the country to order genetic tests for patients.

Moorfields Eye Hospital is also hoping to provide a virtual genomic service to ophthalmologists, to offer guidance and advice on how to manage genetic eye disease patients locally without the need to send them to tertiary referral centres unless necessary. I think this will be a huge step forward for patients who have previously not been able to access genetic services due to local funding restrictions.

I have also created an open access web-resource called Gene.Vision, which is an A-Z of genetic eye disease with two interfaces; one for healthcare professionals and the other for patients. The version for patients includes in-depth sections on how to cope with sight loss and associated aspects of daily life that can be affected, such as driving, education and employment.

The aim of the resource is to feature the signs; symptoms; genetic causes; patient management; referral needs; current information on research and trials for a disease/gene; and any support groups that would be beneficial for the patient, for each genetic eye disease. It has been tested by patients with sight loss with input from digital accessibility consultants, one of who is deaf-blind with Usher syndrome. It will be launched next month (www.gene.vision).

How can you best serve your patients during the pandemic?

Most genetic eye disease patients had their appointments cancelled during the lockdown. When you are forced into isolation, it can cause some individuals to focus more strongly on their own health and well-being.

Calls to sight loss charity helplines increased but they had no expertise to answer the medical queries. So, I offered to undertake a voluntary weekly ‘Ask the expert session’ for Retina UK, Microphthalmia, Anophthalmia and Coloboma Support (MACS) charity and Aniridia Network.

I spoke to at least six patients per session and every caller had a valid reason to get in touch; issues raised included not getting access to expert services, deterioration in vision and interestingly, I received a number of calls from patients who were experiencing increased visual hallucinations as part of Charles Bonnet syndrome (CBS). Based on this anecdotal evidence, we undertook a survey of 45 elderly patients with sight loss due to CBS, with over 40% of them having macular-related disease.

Over 55% of patients reported increased frequency of visual hallucinations;

Approximately 50% had alterations in the nature of their hallucinations and emotional response in terms of more sinister hallucinations, with more associated fear and anxiety; and

Nearly 70% felt greater feelings of loneliness but 60% had not accessed support services.

It is clear from this that we must learn to stay connected with our patients, ensuring they do not feel isolated. Sending a letter of cancellation or discharge is not appropriate during these difficult times. A phone call by an eye clinic liaison officer or genetic counsellor can be very gratefully received by patients. Sight loss charities may be able help in this regard but, like many, they have been suffering from reduced income and furloughed staff. 

Prof. Mariya Moosajee, MBBS, BSc, PhD, FRCOphth

E:  m.moosajee@ucl.ac.uk
Professor Moosajee has no financial disclosures.

COVID-19: How one ophthalmologist is dealing with non-urgent cases 

The femtosecond laser is widely used in ocular surgery, particularly in refractive surgery with LASIK flap creation or small incision lenticule extraction, as well as in corneal graft or corneal inlays for keratoconus. Owing to the very short pulse of the laser, the technology provides highly precise ocular tissue cuttings without causing collateral damage to surrounding structures.

The application of femtosecond laser to cataract surgery was the obvious next step of the technology and has led to femtosecond laser-assisted cataract surgery (FLACS) emerging as a recent breakthrough. However, it has required additional developments such as specific docking systems and real-time imaging to enable cuttings of the opacified crystalline lens to be made without distortion of ocular structures during the laser procedure. Safety zones to preserve surrounding structures within the eye also needed to be considered (Figure 1).

As expected, laser-created capsulotomy is more precise, circular and centred than manual capsulotomy. In addition, corneal incisions have more reproducible squared-edge architecture and greater resistance to leakage than manual incisions using a calibrated knife. Furthermore, the fragmentation of the lens provided by the specific pattern of femtosecond laser impacts within the lens significantly reduces the amount of ultrasound used to remove the remaining pieces of the lens during the phacoemulsification phase.

However, despite the femtosecond laser’s high level of technical capabilities in cataract surgery, the clinical benefit for patients remained unclear and a Cochrane meta-analysis could not determine the equivalence or the superiority of FLACS to phacoemulsification due to a very low certainty of the available evidence and the unclear risk of bias in included studies.

With cataract surgery being one of the most routinely performed operations in medicine, it became clear that such a comparison was necessary, not just for patients but for healthcare professionals and decision-makers as well, to enable them to provide recommendations and potentially facilitate the spread of the technology.

The FEMCAT trial was a large-scale, independent, randomised clinical study which took place at five centres in France. It was designed to compare anatomical, visual and refractive outcomes between FLACS and conventional phacoemulsification cataract surgery among 907 patients (1,476 eyes) who received either bilateral or a unilateral cataract surgery by one of these two methods. We included a wide range of cataract severity grades that were likely to be representative of the French population who undergo cataract surgery every year in France.

The success rate was defined by four relevant outcomes in cataract surgery: the absence of perioperative complications up to the 3-month visit; a best corrected visual acuity of 0.0 LogMAR or better; an absolute manifest refractive error below 0.75 dioptres; and the absence of significant change in corneal astigmatism between the preoperative visit at month 3 post-operatively.

The femtosecond laser was found not to be superior to phacoemulsification in cataract surgery and thus FLACS failed to provide an additional clinical benefit for patients despite its advanced technical performance. Indeed, we observed a high rate of uncomplicated surgery of 94.2% up to the 3-month visit without significant difference between the two groups. These results were recently reported in 

The rate of absolute manifest refractive error below 0.75 dioptres or 0.5 dioptres were up to 81.4% and 76.5%, respectively, again without significant difference between the two groups (Figure 2). Interestingly, we did not observe any difference in visual, refractive or anatomical outcome measures between the two groups whatever the cataract type or the cataract severity grade.

In order to provide robust data on a large sample size, the FEMCAT trial was designed to minimise the risk of bias. We strived to provide masking procedures until the last follow-up visit wherever we could, including having a sham laser procedure for patients randomly allocated to the phacoemulsification group. Additionally, an independent adjudication committee composed of three independent ophthalmologists masked to the trial allocation was designated to evaluate all adverse events for increasing objectivity in safety evaluation.

We also standardised all the associated procedures (IOL optical and biomaterial characteristics or phacoemulsification machines) in each centre to limit the risk of bias and to analyse only the safety and efficacy profile of the studied surgical procedures. Finally, four surgeons experienced in cataract surgery were involved in the trial at each centre. They were also likely to be representative of cataract surgeons in France.

FEMCAT was also a cost-effectiveness trial and so we collected all direct expenses related to the surgery using a real-life micro-costing approach based on detailed resources used during the surgery. It included the prices of items such as knives, viscoelastic products, syringes or cannulas; the expense of the laser and disposable docking systems; and all costs related to phacoemulsification machines.

We also estimated all inpatient and outpatient costs, including those related to the follow-up or rehabilitation care arising until the treatment success measurement was obtained using the French

national health data system, a claim database encompassing 98

.8% of the French population. With comparable clinical outcomes between the two groups, the cost of FLACS was significantly higher and thus the laser was found not to be a cost-effective procedure for cataract surgery.

Indeed, all inpatient and outpatient costs as well as all direct costs of surgical items or phacoemulsification machines were not significantly reduced in the FLACS group. Thus the financial loss incurred by laser was not compensated, even in part, by either better clinical efficacy or a significant reduction in other direct costs during the surgical procedure or thereafter.

It is likely that the technology’s expansion will need to be facilitated by a significant reduction in femtosecond laser procedure costs in the future, including those incurred indirectly, for example by phacoemulsification machines that are used to aspire the fragmented lens.

The femtosecond laser was confirmed to be reliable and precise regardless of the cataract severity grade or the clinical experience of surgeons in our trial. Also noteworthy was that the laser enabled reliable images of the anterior structure of the eye to be obtained irrespective of the cataract severity grade, even for very mature cataracts, and allowed for reproducible cuttings of ocular tissues in the FLACS group.

Moreover, we did not observe any significant adverse event during the femtosecond laser phase. We reported only six cases of incomplete capsulotomy without subsequent anterior capsule tear.

Ultrasound time and energy were also significantly reduced in the FLACS group. Finally, we can also confirm the learning curve of FLACS was short without significant adverse events seen in the first cases by each surgeon.

While FLACS does not provide an additional clinical benefit for patients over phacoemulsification cataract surgery today and was not found to be a cost-effective strategy in our trial, it is fair to acknowledge that this technology is still in its infancy and some perspective exists. Indeed, FLACS has provided new insights into anterior segment surgery, particularly in paediatric cataracts, by enabling posterior laser capsulotomy, which, when it is performed following crystalline lens extraction, could limit the risk of amblyopia related to the posterior capsule opacification.

Additionally, owing to the real-time imaging technology and the three-dimensional zones of laser treatment or safety zones the surgeon can define prior to the laser procedure, this technology can also improve the surgical outcomes of some severe anterior segment diseases such as severe capsulophimosis. The development of new IOLs that would be a better fit to the very precise and circular capsulotomy provided by the femtosecond laser machine could also help improve IOL stability or centration along the visual axis.

Furthermore, innovations such as new aspiration machines associated with the femtosecond laser could help limit the need to use the phacoemulsification machine and reduce the overall cost of the surgical procedure. Finally, FLACS may also pave the way to a new era of automation and robotics in cataract surgery.

In conclusion, we believe that the FEMCAT trial provides useful information that healthcare providers and decision-makers should consider before implementing this new technology in routine practice for cataract surgery. Although FLACS represents an innovation that could open new doors in ophthalmology, it is necessary to rationalise the overall costs of cataract surgery as well as consider the individual patient’s journey when considering whether or not it is appropriate to choose FLACS over phacoemulsification.

Figure 1. Real-time imaging system showing an automated recognition of anterior and posterior faces of the cornea, and anterior and posterior faces of the lens. The green zone is the laser treatment zone within the lens and the red zone is the safety zone based on the pupillary margin and the posterior capsule of the lens. 

(Image courtesy of Dr Cédric Schweitzer)

Figure 2. FEMCAT trial: Safety and efficacy analyses at 3 months in modified intent-to-treat populations.

Dr Schweitzer is an ophthalmologist at Bordeaux University Hospital in France and is the principal investigator of the FEMCAT trial, which was fully supported by a grant for the French ministry of social affairs and health. The French ministry of social affairs and health did not participate in the collection, management, statistical analysis and interpretation of the data or in submitted manuscripts. Dr Schweitzer has no financial disclosures.

With its higher costs, FLACS failed to provide an additional benefit over phacoemulsification for patients or in healthcare settings, despite its advanced capabilities.

Femtosecond lasers and phacoemulsification go head to head in French trial

Much has been published about the risks of contracting Covid-19 from tears and the precautions that need to be taken. This article will evaluate the risks surrounding the most commonly performed procedures during an ophthalmic exam, focusing particularly on procedures requiring contact with the eye, such as tonometry.

Given that the COVID-19 pandemic involves a new virus, which has spread and behaved unpredictably, our understanding of patient management in this new reality has evolved. Consider that in March, a study published in the journal 

 concluded that it was unlikely that COVID-19 patients shed virus through their tears.

However, less than two months later, a new study from Johns Hopkins University, Baltimore, United States, concluded differently: “These results indicate that ocular surface cells including conjunctiva are susceptible to infection by SARS-CoV-2, and could therefore serve as a portal of entry as well as a reservoir for person-to-person transmission of this virus.”

 They added that the results showed that the ocular surface could be an even more significant reservoir for virus particles than suggested by other recent clinical studies.

Given these recent findings, we must be vigilant about reducing the risk of virus transmission for our staff, as well as our patients. In our clinic, we have implemented specific safety measures that should reduce the risk of infections in general.

These include: providing face masks to each patient when entering the clinic; measuring body temperature by a non-contact method; excluding patients with any potential COVID-19 symptoms; frequent ventilation of all rooms; adding barriers around instruments and the reception area; and disinfection of all surfaces every hour. We have also made it mandatory for the entire clinic team to wear gloves, safety glasses and facemasks.

According to a World Health Organisation-funded study, face masks and eye protection/safety glasses provide the best protection in reducing the risk of infection. Writing in the 

 the researchers looked at 216 studies with more than 25,000 COVID-19 patients and found that face masks resulted in the largest reduction of risk (95% CI: 0.07–0.34), followed by eye protection (95% CI: 0.12–0.39).

Until we have a vaccine and see a reduction of COVID-19 cases down to zero, we must adjust and take every precaution possibly to protect our staff, as well as our patients.

Ophthalmology Times Europe September 2020

Amblyopia screening with the dynamic random dot stereotest

Using swept-source OCT and OCT angiography to image choroidal tumours

Monitoring blood reflux during gonioscopy in glaucoma

COVID-19: How one ophthalmologist is dealing with non-urgent cases

Femtosecond lasers and phacoemulsification go head to head in French trial

Minimising risks during routine ophthalmic examinations in the COVID-19 era