Many, or most, clinical commissioning groups have criteria for cataract referral. Many adopt a three-way check; is it a cataract causing visual loss, is it interfering with quality of life and are they willing to undergo surgery? Laudable, but then topped off with Snellen VA worse than 6/12! How many times have you referred a symptomatic patient who returns because the HES won’t list them? Why does this happen and what should you do about it?
After you have checked your chart calibration, you can, if you are lucky enough to have received a reply, start by wondering about their 6/9 and ignoring the patient’s symptoms. First there is natural variability between tests and a phenomenon called ‘regression to the mean’ which usually rears its head in IOP measures. Measure again.
Secondly there is dissonance between what the patient tells you, and what they tell the busy white coated ophthalmologist in an overbooked clinic (and what they are asked). Even if you say they are the only family driver, that they are symptomatic for disability glare, that they struggle to read and are a fall risk, do those questions get repeated? Are the optometrist’s measures of vision taken seriously?
In a timely paper in an ophthalmology journal1 we are reminded of the profound shortcomings of Snellen. Blecher argues for standardisation and the use of low contrast ETDRS charts for visual function assessment.
It is amusing that it is only recently that ophthalmologists (anti-VEGf) and orthoptists (amblyopia) are using logMAR, espousing the principles of the optometry designed Bailey-Lovie charts laid down 40 years ago.2 Sadly community optometrists have taken longer. The minimum requirement for a chart is logMAR scaling, so you don’t miss out on important lines and an equal task (five letters per line). It is important to have a low contrast facility or Pelli-Robson, and most underrated contrast inversion. There is a dramatic difference in the visibility of letters black-on-white compared to white-on-black in the presence of media opacities.
Finally if you get a symptomatic patient knocked back, write directly to the consultant and ask for it to be reviewed. The junior doctor who assessed just might have been less experienced than you, or the VA may have been affected by the financial year of the HES clinic!
1 Blecher, M. (2014) Why Snellen must die.
https://theophthalmologist.com/0314/
2 Bailey IL, Lovie JE. New design principles for visual acuity letter charts. Am J Optom Physiol Opt, 1976; 53(11): 740-5.