ARVO 2020 latest research updates

 M. ZHAO, A. Lam, A.M. Cheong, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, HONG KONG|L. Qin, Tianjin Medical University Eye Hospital, CHINA|M. Ying, Department of Health Technology and Informatics, The Hong Kong Polytechnic University, HONG KONG

Mei Zhao and colleagues from Hong Kong Polytechnic University explained that myopia can change the vasculature of the eye due to axial elongation, but no central mechanism or factors connecting the changes has been discovered. The authors explained that OCTA imaging has shown that the stretching of the eye during myopic growth may change the way the vessels behave in the eye, and cause reduced capillary perfusion in the peripheral retina. In their study they recruited 108 healthy young myopes, (mean age of 25 and axial length of 26mm) and conducted OCTA scan to observe superficial perfusion density, and standard OCT in the same section to look at choroidal thickness. Findings were similar to previous studies: myopes have reduced perfusion, increased resistance and lower mean velocity of blood flow. When they controlled for axial length, though, there was no correlation between the choroidal thickness and perfusion density.

This adds to the growing body of knowledge that myopic stretching of the eye causes multiple ocular health complications - needing glasses is just the tip of the iceberg! These findings don’t yet allow for clinical use of a central OCT scan to determine a patient’s peripheral vascular risk profile, and whether this could provide some idea of risk for complications.

Link to Abstract  

K. Honda, Santen Pharmaceutical Co., Ltd., Ikoma, Nara, JAPAN|T. Imanaka, Santen Pharmaceutical Co., Ltd., Osaka, JAPAN|

Presented by Kohei Honda & Takahiro Imanaka from Japan, the authors highlighted the lack of consensus in previous research on the relationship between IOP and myopia. A variety of longitudinal and cross-sectional study designs, involving both children and adults were evaluated. With 19 articles selected for qualitative analysis, 14 concluded that there is a relationship between higher IOP and higher myopia. The authors adjusted for age as the most important confounding factor, as age can correlate with both IOP and myopia; and noted that further work needs to be done to understand the relationship when controlling for other factors.

Nothing quite yet, as the correlation hasn’t been narrowed down enough to be able to use IOP as a predictor for myopia level or even progression risk. However we do know that myopia is connected to higher risk of glaucoma, so this really reiterates why measuring IOP in your myopic patients (young and old!) is important.

Link to Abstract 

R. Xu, R.R. Krueger, Ophthalmology, University of Nebraska Medical Center, Omaha, Nebraska, UNITED STATES|R. Xu, M. Jaskulski, B. Bradley, P.S. Kollbaum, Optometry, Indiana University, Bloomington, Indiana, UNITED STATES|M. Jaskulski, VisionApp Solutions S.L., SPAIN|

Presented by Renfeng (Rena) Xu and an international team, the authors highlighted that 96% of Chinese University students are myopic, with schools now being adapted to tackle this through increasing classroom illumination and near working distance. The study was focussed on assessing measurement accuracy of a phone app called “VisionApp” (marketed as Myopia.app) that continuously monitors the ambient lighting levels and phone viewing distance. In children aged 6-12 years, average viewing distance was 24cm, considerably shorter than the average 45-50cm the authors report as typical for adults. The study children were found to hold the phone closer at 21cm when reading small text and further at 27cm when playing video games or watching videos in the dark. Considerable variation was also reported of up to 3D viewing demand between participants - the authors speculated on the link between closer distance and myopia, although this was not measured.

Children like holding things close, especially small print on a phone so advise parents to watch out and help their children adopt safer longer viewer distance - keeping the phone at fingertip to elbow length being an easy measure to adopt.

Link to Abstact

J. Foreman, A. Salim, D. Fonseka, M. Dirani, Plano Pte Ltd, Singapore, SINGAPORE|J. Foreman, Ophthalmology, University of Melbourne, Melbourne, Victoria, AUSTRALIA|M. Ang, A. Chia, Singapore National Eye Centre, SINGAPORE|M. Ang, Duke-NUS Medical School, National University of Singapore, SINGAPORE|T.Y. Wong, J.G. Crowston, Singapore Eye Research Institute, SINGAPORE|T.Y. Wong, J.G. Crowston, M. Dirani, Duke-NUS Medical School, National University of Singapore, SINGAPORE|

Using their data collecting app (Plano.co) the authors analysed data collected from over 59,000 children with an average age of 8 across Singapore, India, Malaysia, Australia, Bangladesh, United States Philippines and Indonesia.

They found that only 22.6% of all the children measured had ‘ever’ had an eye examination. 9.0% of children across the entire cohort had their eyes examined within a 1-year period up to November 2019, lowest in the Philippines (2.5%) and highest in Singapore (15.1%). Being female, or having siblings increased likelihood of eye examinations slightly. The finding with the most impact, however, is that children aged 8-11 were 1.7x more likely to have had an eye exam than their younger peers, this odds ratio increasing to 3.3x in the Singapore cohort. In addition to the obvious shortfall in basic health care from three quarters of the measured children having never had an eye examination, these data convey that younger children in particular are not having their eyes examined and that children with myopia are not undergoing regular eye examinations.

It’s up to us as eye care practitioners to convey to parents the importance of eye examinations in their children, and particularly to advise examinations in younger children even if not symptomatic. Furthermore, we should be aware of the potential of myopic children to miss regular eye examinations at this crucial stage in their life where ongoing progression of myopia needs to be closely monitored. 

Link to Abstract

S. asghar, W.K. Stell, Cell Biology & Anatomy, university of Calgary, Calgary, Alberta, CANADA|

Across two studies the authors investigated how atropine interacts with muscarinic receptors in chicks to influence development of form deprivation myopia. In the first experiment they showed that atropine inhibited form deprivation induced myopia (FDM) eye growth, however it’s muscarinic receptor targeting enantiomer l-hyoscymane didn’t. In the second study they show that both benzetimide, which has similar pharmacological actions to atropine, and it’s muscarinic receptor targeting enantiomer dexetimide both inhibited FDM eye growth. The results from the combination of these two studies demonstrate that pharmacological inhibition of form deprivation induced ocular enlargement is not mediated by muscarinic receptors alone.

Though mechanisms of action remain unclear, we know that atropine does slow progression of myopia in humans, and has a clear dose-dependent response, meaning that atropine should be included as a myopia management treatment strategy where appropriate for your patient. Meanwhile, ongoing research studies continue towards building understanding atropines mechanisms of action in slowing progression of myopia, and in doing so will likely lead to more specific and effective anti-myopia drugs.

Link to Abstract

Sandra Wagner; Arne Ohlendorf; Siegfried Wahl; Frank Schaeffel; David Troilo

The accommodation response in multifocal contact lens (MFCL) wear could influence myopia control efficacy, and previous studies have shown that non-presbyopic MFCL wearers may relax their accommodation and use the ‘add’ at near, generating a larger lag of accommodation. This study used custom-developed photorefractor software to measure the lag and found it to be greater in young adult myopes wearing MFCL compared to single vision soft contact lenses (SCL) or trial spectacle lenses. They then undertook auditory biofeedback training for 200 seconds and found lag reduced in all three correction scenarios, but less so for the MFCL wearers. The authors concluded that while biofeedback training improved accommodative accuracy (reduced lag) in young myopes, it was less modifiable in MFCL wear and further training may be required.

There’s a building volume of research that MFCL wear reduces accommodative response (increases accommodative lag) in children and young adults, and that a reduced accommodative response may be correlated with a reduced myopia control effect. The auditory biofeedback training undertaken here improved accommodative response, but this improvement was less predictable in MFCL wear. It is not yet commercially available, but there are other clinical methods available to increase accommodative response. This research points to the value of assessing accommodation in young myopes – a normal accommodative response is important for visual comfort, and seems to be increasingly valuable in achieving myopia control efficacy. As we learn more about the interaction between MFCL and accommodation, it may be in future that we select a specific type of MFCL for the individual myope based on their accommodation, and/or we seek to improve accommodative responses through specific corrections or training, to optimize myopia control efficacy.  

Link to Abstract

Qiu Ying Wong; Yee Shan Dan; Daryle Jason Go Yu; Quan V Hoang; Chee Wai Wong

Adult high myopes (6D or more) with axial length minimum of 25mm in at least one eye were evaluated for myopic macular degeneration (MMD) by the META-PM category system, and classified into ‘MMD absent’ (categories 0-1), ‘mild MMD’ (category 2) and ‘severe MMD’ (category 3). Macular sensitivity was assessed with microperimetry at 2, 4 and 6 degrees diameter of fixation. As expected, reduced sensitivity was correlated with more severe MMD. After adjusting for several factors, longer axial length was independently associated with worse macular sensitivity. Furthermore, while ‘absent’ and ‘mild’ MMD categories had similar best corrected visual acuity (BCVA), the ‘mild MMD’ category showed reduced macular sensitivity, indicating this microperimetry test could be a more sensitive marker of visual function in eyes with macular disease than BCV

The pervasive frequency of myopia in Singapore provides a volume of opportunity to understand the visual sequelae of high myopia. In this study, highly myopic adults with diffuse chorioretinal atrophy (META-PM Grade 2) showed reduced microperimetric macular sensitivity before any loss of BCVA, when compared to eyes without MMD. With an average age of 54 years and axial length of 28mm, these patients reflect people of working age likely to be seen in routine clinical practice and not just in tertiary retinal care. While longer axial length was associated with reduced macular sensitivity, although only 15-25% of the loss of sensitivity was explained by axial length indicating other factors can be at play. This underscores the importance of monitoring retinal health closely for any patients with longer eyes and high myopia, and points to use of microperimetry – more commonly used in retinal subspecialty tertiary eye care – as a more sensitive clinical tool than BCVA for monitoring the at-risk and compromised macula. 

Link to Abstract

Noel A. Brennan; Saiko Matsumara; Hla Myint Htoon; Biten K Kathrani; Chuen Seng Tan; Carla Lanca; Donald Tan; Charumathi Sabanayagam; Seang-Mei Saw

Annual rate of myopia progression from an existing dataset is used to determine if rate of subsequent years of myopia progression can be reliably predicted, to reveal a statistically significant though only modest clinical relevance of myopia progression from one year to the next, with no improvement to the model from averaging up to three prior years of myopia progression measurement.

Reliance on prior annual rate of myopia progression alone is not a reliable enough predictor for subsequent years of progression. Consequently, myopia management strategy for a given individual should be determined based on multiple patient-specific factors including myopia progression in the previous year, higher initial SE, age of myopia onset and parental myopia. 

Link to Abstract

Daniel Ian Flitcroft; James Loughman; Baskar Arumugam; Arthur Bradley; Paul Chamberlain

Translating clinical trial results into clinical practice is made difficult by differences in participants vs patients and applying clinical trial analysis to a practice setting. The authors introduce the concept of using growth (centile) charts to monitor myopia progression and use these charts to assess the previously conducted MiSight 3-year data set to establish a good fit between the published outcomes from the clinical trial and representation on changes to centile chart tracking. This research establishes centile charts as a useful tool to use in clinical practice to determine successful outcome from a myopia control intervention.

Centile charts offer a simple way to monitor myopia development in an individual to determine whether they are likely to be slow or fast Progressors and whether a myopia control intervention is having an effect. However, while this provide promise, they are still at a relatively early stage of development. 

Link to Abstract