Exploring Reported “Favorable VA Outcomes” in Children with Primary Congenital Glaucoma and Surgery

An article in the European Journal of Ophthalmology recently featured in the press reported on the long-term outcomes in children with primary congenital glaucoma (PCG) who underwent angle surgery.  The author of this retrospective study over a 21-year period reported the conclusion that “a favorable visual acuity (VA) outcome was achieved”.  As an eye doctor who has focused my entire clinical career on improving the treatment and management of chronic vision impairment, any and all improvement or preservation of visual acuity is of utmost importance to my patients and me.  And nowhere is it more impactful than in young children we care for who face decades of life, years of education, developmental growth, peer milestones (i.e., driver licensure), and emerging careers – all of which are greatly impacted by the health and function of the eyes and visual system.  A layperson reader who comes across this abstract, or a reader unfamiliar with clinical outcomes other than surgical – such as the large body of evidence on impacts and outcomes related to chronic visual impairment of all presentations and diagnoses – may assume that things are relatively well and good for this patient population due to ‘angle surgery’.  One can see that parents or stakeholders reading this could easily assume that children who are presented with a surgical option defined in this report as “trabeculotomy, trabeculectomy, or combined trabeculotomy-trabeculectomy” will achieve a “favorable” visual outcome.  But what does “favorable” mean to me as the doctor, to the parent of the child, as a prognostic indicator?  This is exactly the type of evidence we as doctors consider in our patient care as part of the face-to-face doctor-patient relationship critical to quality comprehensive eye care.  This relationship is key to shared clinical decision-making (SDM) where we as doctors present the treatment options available, the pros and cons, risks and benefits – and ask patients to share their preferences based on our discussions, to best formulate the patient’s care plan.  And this shared decision making is a fundamental component of our care that is not replaceable with a virtual health test – there is no app for that.   The author also reports that “topical antiglaucoma medication has an adjuvant role in maintaining the success rate of surgery without risking the visual outcome”. So, pharmacological therapy enhances surgical outcomes according to the author.  And so multiple factors are now at play in reaching the reported conclusion:  there is the consideration of surgery and /or a combination of surgical procedures, plus the additional use of topical medication over time to consider as contributing to “a favorable VA outcome”.

As doctors of optometry, formally trained didactically and clinically in vision impairment and its proper care, a requisite deep dive into how the authors define “favorable VA” is required.  In this case,  the main acuity outcome measures were defined as:

  • “final best-corrected good VA (20/20 to 20/50)”
  • “moderate VA (<20/50 to 20/200)”
  • “poor VA (<20/200)”

From the “53 eyes” included in the study, the authors reported that:

  • “good VA was attained in 51%”
  • “moderate VA in 30%”
  • “poor VA in 19%”

(NOTE:  the author also reported on additional findings including a “primary cause (64%) of acuity less than 20/50 due to ‘deprivation amblyopia’ “, and refractive findings that included a “mean spherical equivalent of -4.47 ± 5.66” with “high myopic shifts associated with the “visually impaired” group”.)

If we closely evaluate these findings we see that, in comparison to the 51% of children’s eyes found to have “good” acuity, almost an identical number of children’s eyes – specifically 49% – were found to have “moderate” to “poor” visual acuity.  An almost even split.  And to put this into even clearer practical terms:  for starters, based solely on these findings, at least half of the children as reported will struggle with reading ‘normal’ size print and seeing clearly far away at the same time; they may not qualify for gaining unrestricted drivers licensure; they will most likely lose additional vision over time; and they may live their lives as “functionally monocular”, meaning a life-long requirement for full-time safety lenses and frame protection to meet legal and ethical clinical standards for eye safety and protecting remaining vision.  On top of this, we cannot assume that the 51% of children in the “good” category will see or function as would be expected within our clinical ‘normal range of vision’ due to “corneal opacification and anisometropia” and other factors reported on by the author, in addition to what we already know from other related studies and evidence. And, most importantly, the author reports on favorability linked to only piece of the eye care continuum – the surgical intervention that may reduce the devastating impacts of glaucoma on the structure of the eye.  This study, like so many others, does not address the downstream effects of “non-favorable” outcomes for 49% in this instance – nor does it include how children with chronic visual impairment resulting from glaucoma, with surgical intervention, and with topical treatment – require vision rehabilitation treatment and ongoing care as the only remaining option for improving the quality of visual input, improving acuity and other glaucoma-related effects (i.e, loss of visual field, sensitivity to light, decreased contrast) and maximizing visual function to meet quality of life goals.  The author chose to frame “favorable VA outcomes” in a way common to those who are not familiar with the multitide of impacts of vision impairment, by choosing a single metric concept of favorability – an important one, but an isolated one nonetheless.

This langauge matters in how we advocate to our patients for available treatment options and determine our recommendations for patients and stakeholders.  This matters in how we incorporate patient preferences and evidence into our discussions. And as I advocated for within the National Academies of Science, Engineering, and Medicine (NASEM) report, it matters to the surveillance of vision impairment in the U.S., in how researchers view and classify vision loss, to the understanding of the comprehensive continuum of eye care from prevention through tertiary care, and how clinical outcomes are impacted along the way.  It is important to how our nation increases its awareness of the life-changing opportunities we as optometrists – and as the primary providers of treatment for vision impairment and vision rehabilitation care – provide for people of all ages who live with less than perfect vision, and how decision makers view the eye care continuum as a necessary part of integrated health care. Words will continue to matter, and I’ll keep fighting to make sure attention is paid.

 

 

 

 

 

 


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