History and symptoms • When was the onset of the turn? The onset is important as it can help to classify the strabismus. If the squint is present before the age of one then it could be known as infantile esotropia, this is idiopathic and can occur up the age of six months, due to the imbalance of the eye muscles. If a squint has presented itself in children who are 2years old or older, then this could just be as simple as uncorrected refractive error. As uncorrected refractive error can induce strabismus, this is due to the poor focusing factors.
Accommodative esotropia, this tends to happen to children when they start to explore near work. Is the squint present all the time? Is the squint present all of the time? If yes, then this could be because of a mechanical problem. If the squint isn’t present all of the time, then I would use follow up questions such as, when is it most likely to occur? If it is most likely to occur when the child is tired, this could be a refractive error problem. Also known as accommodative esotropia. Accommodative esophoria is intermittent, and overtime it can become more constant. • Which eye turns in? Or does it alternate? If only one eye turns in, this then increases the risk of amblyopia.
Amblyopia can occur in the eye which is turning in, as this enables the brain to suppress the image in this eye. In an alternating esotropia, amblyopia is not a big concern as both of the eyes do have time to fixate. • Does it get worse with particular tasks? Distance blur after near tasks! Accommodative esotropia occurs due to the amount of effort which has to be put to look at a near target. •Any headaches? Headaches can help indicate some neurological defect, and accommodative problems. • Are you getting any double vision? If the child does get double vision, then I need to ensure they are not getting confused with blurred vision.
I would also get the child to cover one eye at a time to ensure that the double vision is occurring due to a binocular vision problem. However, it is not common that the child will get any diplopia. • Is your vision blurred? If the child has blurred vision, this this would suggest that there is a refractive error present which could be causing the esotropia. • Closing of one eye? If yes, this this could be a result of amblyopia as the child just feels that when their binocular the vision isn’t just as “crisp”, compared to when the weaker eye is covered. • Is there a family history of squints? Or glasses?
If there is a family history, then this would increase the risk of the child. · What was the pregnancy like, full term and normal birth? Premature babies who are under 5. 5pounds or under 36 weeks are at greater risk of strabismus. A complicated birth has also been known to increase the risk, such as forcep birth, this is due to where the forceps are placed on the baby’s head.
• Previous treatment/ glasses? At the beginning of the test we found out that it was the child’s first eye examination, so in the case we know that all the above question is not relevant. Therefore, we can rule out consecutive esotropia. General Health? Fatigue, nausea/vomiting, thyroid disorders, diabetes, down syndrome, cerebral palsy, gross developmental delay. If a systemic condition is present, this tends to lead to an accommodation problem. If there is on systemic condition, then we are able to rule out secondary esotropia.
• General observation of patient-head tilt, facial palsy, protosis, ptosis, lid retraction? If the patient is tilting then this can help indicate that there is a binocular vision problem. They could be tilting their head to try and stop diplopia from happening, this could also indicate that there is a problem with ne or more of the oblique muscles. Pickwell, D. (1989). Binocular vision anomalies. 1st ed. London: Butterworths. Ocular motility Ocular motility test will help to detect whether or not the extra ocular muscles are working in the eight positions of gaze. In most people you can see end point nystagmus. However, if the nystagmus is present before the endpoint, I would then be concerned about a neurological problem. Also if there was a restriction on any of the position of gaze, then the binocular problem could be because of the extra ocular muscles. In this case the muscles are not the cause of the esotropia.
Measuring the Visual Acuity Depending on the child which I am testing, I could use crowed Kay picture or Keeler logMAR at 3m, as these tests are more sensitive in picking up amblyopia. Z,A. (2016) Equal visual acuity can mean that the onset is recent. Unequal visual acuity can suggest that the deviation has been there for a while. Refraction: To carry out this refraction I would use cyclopentolate 1%, as the mother has a noticeable concern of a squint. Cycloplegic refraction helps to control accommodation to ensure we get an accurate result, get a better view of the health of the eye, so that we can rule out any pathology.
The refractive error can help give an indication of the type of deviation. If the child is found to be hyperopic, then this could be the reason why the eso deviation has occurred. The hyperopic refractive error is usually around +2. 00 – +6. 00D. Anisometropia which is more than 1 D or more can be present in the deviating eye. If the visual acuity in both eyes, when corrected didn’t bring the child up to a good level of acuity, then I would be starting to think about retinopathy and macular problems. In this case there is a hyperopic refractive error.
Cover test: A cover test will help to differential diagnose. While doing this test I would estimate size of deviation or I could measure the deviation with the Hirschberg test with and without glasses. I would also look at the speed of recovery to ensure if a phoria was present that it wasn’t breaking down into a tropia. Partially accommodative esotropia Cover test without glasses- When the child looks at a near target (budgie stick, as it is a good accommodation target), there will be an increase in the esotropia. When the distance target, there will be a decrease in the esotropia.
Cover test with glasses- The angle would been greatly reduced when the child is looking at a near and distance targets, however the esotropia would still be present, this is due a problem with one/ more of the extra ocular muscles. Fully accommodative esotropia Cover test without glasses-When the child is looking at a near target the esotropia increase. When the child is looking at a distance target the esotropia decreases. Cover test with glassesWhen doing a near/ distance cover test, there is no manifest strabismus. The esotropia fully corrects with the hyperopic prescription.
Accommodative esotropia with convergence excess Cover test without glasses- When looking at near target the esotropia will increase. When looking at distance target, the esotropia would decrease. Cover test with glasses, there is no manifest strabismus, reduced esotropia or orthophoria. Accommodation, convergence and the AC/A ratio As I applied cyclopentolate for my refraction, this has stop any accommodation/convergence. Therefore, I would have to ensure that when the child returns to lift their glasses, that| measure the accommodation and convergence.
This should be done with/without glasses. A convergence/accommodative insufficiency can also be the reason in which the blurred vision can occur. The convergence would also increase as the hyperopia increases. The AC/A ratio is normal at 4. 1 in patients with a fully accommodative esotropia. However, it appears to be high 8. 1 in partially accommodative and accommodative with convergence excess. Mutti, D. , Jones, L. , Moeschberger, M. and Zadnik, K. (2016). Stereopsis Stereopsis test is important to ensure that the child has depth perception.
People who have a binocular vision problem usually have a lower stereopsis. There are a range of different test that can be used. I would use the randot fly as I find the child finds it more interesting. If the child didn’t cooperate well, then I would use the frisby stereopsis. Elliott, D. (n. d. ). “In the absence of significant refractive error, strabismus, or reduced or unequal acuity, most 4-year-old children should have a Randot stereoacuity of 70 seconds of arc or better and most young school-aged children should have a Randot stereoacuity of 50 seconds of arc”. GL, K. 2016)
To measure the simultaneous perception and sensory fusion, I could use the Worth’s 4 Dots/ Lights test. Also if I wanted to measure all three perceptions together, I could use an synoptophore, however this might not be achievable as the patient is only four. Colour vision: I would carry out this test on every child if it was their first sight test. Also this child is only four years old, and also has an increased risk of a colour vision defect as they are a boy. This test won’t help to detect the binocular vision problem, however it can help to detect if the binocular vision problem has occurred due to pathology problems.
Management of a fully accommodative esotropia: Prescribe full cycloplegic refractive error, for full time wear. If amblyopia is present I would monitor the child with the full prescription and see does it improve any. Around 16 weeks if there is no improvement to the amblyopic eye, I would then think about occlusion. Occlusion would then be part-time to ensure we don’t dissociate the latent component. Orthotics exercises could be carried out. Aapos. org. (2016). Up to the age of eight this is known as the critical period as the eyes are still developing. This is why it’s so important to prescribe full prescription.