I’m A Seoul Man

Research out of the Seoul National University Hospital in South Korea, published in Graefe’s Archive for Clinical and Experimental Ophthalmology (2022) substantiates that there is more that can be done for children with strabismus or amblyopia than surgery or patching, particularly when the angle of strabismus is small. Semantics first: the authors define small angle as </= 8 prism diopters. Their approach was to use Fresnel prism to neutralize the strabismic angle to ortho as viewed on the unilateral cover test. The Rx was worn full time, with compliance estimated at a rate of 80% in wearing the Rx. Follow up was at least 24 months.

There are limitations to this study, to be sure. It involved only 20 patients, and was done through a retrospective review of records without any control group. It would never pass muster as a “gold standard” study, and is light on data and details, but it moves the needle on an important conversation about doing more for these patients than judging success by cosmesis.

The two main parameters the Seoul authors used to judge success were:

  1. For monofixation syndrome (MFS) status, stereoacuity values on Titmus Wirt Circles
  2. For amblyopia, changes in Snellen visual acuity

Some of the patients had impressive changes in stereoacuity or Snellen acuity, even though the motor angle remained the same. Using these two measures of non-random dot stereopsis, and Snellen acuity is in line with what we have previously blogged about based on Sherman’s BSI or binocular success index.

Changes with prism aren’t typically instantaneous, and have to be monitored over time. Children and parents have to be reminded to be consistent and patient with using Rxs that incorporate prism, often in amounts that seem too small to be efficacious. As Sam & Dave originally sang, and Akroyd & Belushi popularized, “Don’t you fret ’cause you ain’t seen nothin’ yet”.

One thought on “I’m A Seoul Man

  1. Prism treatment is important and included in the sequential management considerations for all VT patients – which is to be accepted or rejected by the OD-VT based on the patient’s diagnosis.

    With most OD issues (vt or pathology) there is usually a sequential management considerations with options for treatment to be accepted or rejected by the OD and then presented as one of the treatment plans along with doing-nothing/monitoring and others as informed consent of treatment options for the patient to select.

    Experts in vison therapy use and recommend the following VT sequential management considerations to be applied to all candidates for vision therapy. It is up the OD-VT to accept or reject each of the considerations based on the patient’s diagnosis to make a VT treatment plan to be included in the informed consent of treatment options when counselling the patient.

    Vision therapy sequential treatment considerations include:
    • Lens prescription and wearing time
    • Added Lenses (Plus or Minus) at distance or near
    • Prism (horizontal or vertical)
    • Occlusion
    • Vision therapy: AC Treatment
    • Vision therapy: Active Amblyopia
    • Vision therapy: Anti-suppression
    • Vision therapy: Sensory / Motor
    • Surgery
    • Maintenance / Monitor Therapy

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