"Through My Lenses"
Mohd Naim bin Rahim / 0818189Assignment 1: Pediatric OptometryDiscuss about the factors that should be considered before prescribing a correction on astigmatic patient (pediatric)It is known several decades that infants have a very high incidence of astigmatism. It is also known that this astigmatism decrease in degree and in incidence with increasing age. Infants show ten times more incidence compared with school age children and considerably greater degrees of clinically significant astigmatism than older cohorts, according to Mohindra et al.Before prescribing correction on astigmatic children, several factors should be considered. These factors are age, acuity and degree of astigmatic power. 1) AGEA child with significant astigmatism needs correction, but the correction depends on age. It is well known that astigmatism in infants is prevalent and it decrease with age. It has also been shown that meridional amblyopia does not occur until about 2 years of age. So, no need to correct astigmatism until the children approaching 2 years.2) STABILITYStability is also important in determining the appropriate time for prescribing correction. For example, in examining a child at 9 months, finding is one eye plano/-4.00D x 90. When refraction is done 3 months later, it shows same correction. Another follow-up at 15 months reveals the exact same -4.00D x 90. This is a cylinder that not changing and correction should be given. In other example, if this child comes to the first visit demonstrating -4.00 x 90 cylinder, 3 months later, refraction show -2.00 x 90 and 3 months after shows -2.00 x 90. So, continue to watch this child until the astigmatism becomes stable and then consider prescribing, if necessary.3) ACUITYAnother factor to consider is visual acuity; both uncorrected acuity and best corrected acuity. If as monitor the patient, the best corrected acuity is decreasing, consider prescribing lenses for toddler patient. Consider delay the spectacle correction if the best corrected acuity remains the same.4) DEGREEIf infants comes with significant astigmatism (>3.00D), certainly consider prescribing corrective lenses.ReferenceRobert H.Duckman, 2006, Visual Development, Diagnosis and Treatment of the Peadiatric Patient
Discuss about the factors that should be considered before prescribing a correction on astigmatic patient (pediatric). The factors to consider before prescribing a correction are age, acuity, degree and stability. It has been observed and known for several decades that infants have a very high incidence of astigmatism. It is also known that this astigmatism decrease in degree and in incidence with increasing age. The degree of astigmatism begins to decrease in the second year, and the incidence declines during the third year. It has also been shown that meridional amblyopia does not occur until about 2 years of age. Therefore, no need to correct astigmatism until the child is approaching 2 years of age. After 2 years and above, it become essential and important to correct astigmatism. Another factor to consider is visual acuity. If as monitor the patient, the best corrected visual acuity is decreasing, consider prescribing lenses for the toddler patient. If the best corrected acuity remain the same, consider delaying spectacle correction. In term of degree, if an infant comes in with significant astigmatism (>3.00D), certainly consider prescribing corrective lenses. However, before giving the prescription, monitor the child carefully and often. For instance, in examining a child at 9 months, findings are UO plano/-4.00DCx90. Recheck the refractive error 3 moths later and find the same correction. Another follow-up at 15 months reveal the exact same -4.00DCx90. This is a cylinder that is not changing and correction should be given. Besides, the astigmatism can be monitored and evaluated every 3 months until stability is reached or the refractive error is no longer present. When the astigmatic error stabilizes, if correction is needed, full correction or mild under correction of 0.5D is advised. This must be considered within the context of the cylinder axis. Slight under correction for –x180 and –x90 cylinder is appropriate. Oblique cylinder should be corrected fully, however.
Mohd Naim bin Rahim / 0818189Assignment 1: Pediatric OptometryDiscuss the tests that should be done to diagnose an amblyopia children.Amblyopia is defined as reduced vision in one or both eyes caused by visual deprivation in childhood. Amblyopic condition does not improved by glasses and it is not due to ocular abnormalities. There are several tests that could be performed to diagnose someone to have amblyopia.Rober H.Duckman has suggested MEAC approach to help to rule out the amblyopic patient. Then MEAC approach is the acronym for;1. M-Monitor qualitative fixationVisual acuity is evaluation. The fixation ability is measured grossly or quantitatively as needed. The tests that should be used to measure visual acuity is respected and appropriate with the level of peadiatric patient. 2. E-Evaluate red reflexRed reflex evaluation is done to detect any strabismic eye. Bruckner test have to be done to compare the brightness of the red reflex. Whiter/brighter reflex represent a strabismic eye. 3. Alignment EvaluationKappa Hirsberg test is needed to see the alignment of the eyes. Kappa Hirsberg test is done on infant while cover test is acceptable test to evaluate the alignment of the eye on toddler.4. C-Compare refractive errorCycloplegic refraction is done to the pediatric patient to observe any difference between refractive error in two eyes.When all the tests done, the results should be compared to rule out the classification of amblyopia condition.Reference:Robert H.Duckman, 2006, Visual Development, Diagnosis and Treatment of the Peadiatric Patient
What tests must be done on pediatric patient to confirm that patient is amblyopic. Explain it. To rule out the presence of amblyogenic risks, the following steps should be taken: First is visual acuity evaluation. The gross monocular fixation abilities or a quantitative measure are taken. Eccentric or monocular fixation is a condition that exists only in amblyopic patients. It occurs when the amblyopic eye actively attempts to fixates with an off-foveal point under monocular condition. Eccentric fixation affects visual acuity, therefore it is important to be aware of it clinically. Visuoscopy is the most common clinical tool used to assess eccentric fixation (EF) in an amblyopic patient. The grid target on a direct ophthalmoscope is used to determine the presence of EF, as well as its magnitude and direction. It must be done with the patient’s eye not being tested occluded because EF is a monocular condition. Second is Bruckner test. It is to evaluate the quality or sameness of red reflex (a whiter or brighter reflex represents a strabismic eye). It also permits a qualitative judgment regarding the alignment of the eyes anisometropia. Suspicion of the presence of these two major contributors to the development of amblyopia, therefore can be increased or decreased by a quick and simple screening test. Evidence suggests that Bruckner test is more reliable when the patient is 8 months of age. Both pupils are visualized simultaneously and the brightness of the red reflexes compared. The eye with the brighter reflex is presumed either strabismic or more anisometropic. Third is alignment evaluation. This is to rule out strabismus; which are, Kappa/ Hirschberg for an infant, and cover test for a toddler. The Hirschberg test is performed at a distance of about 50cm from the patient, with the light aimed directly at the bridge of the patient’s nose. The strabismic magnitude determined by estimating the position of the fixating eye’s reflex compared with that of the deviating eye. At times, the corneal reflex is so close to the expected norm that it is difficult to know which is the fixating and which the turned eye is. To be certain, look at the monocular corneal light reflex. It is defined as angle lambda, which means the angle between the centre of the entrance pupil and the visual axis. Fourth is cycloplegic retinoscopy. The refractive error is compared between two eyes to rule out isometropic or anisometropic amblyopia. Anisometrpoic amblyopia is a unilateral decrease in visual acuity occurring with unequal, uncorrected refractive error that is present before 6 years of age. Anisometropic images differ in clarity, contrast, and size causing a lack of visual stimulation to the eye with the greater significant refractive error. If left untreated, the eye with the higher refractive error may develop a strabismisc deviation. The degree of anisometropia needed to elicit unilateral amblyopia differs with each type of refractive error. The risk for hyperope is produced with as little as a +1.50DS difference between the two eyes. The lesser hyperopic eye is used for fixation at all distance, whereas the more hyperopic eye receives an unclear retinal image, resulting in suppression. Myopic anisometropic amblyopia has more liberal base for amblyopia development. Greater than 3D difference between the two eyes must be present to produce the risk of anisometropic amblyopia. The need for a more substantial difference between the two eyes is because the eye with less myopia will receive visual simulation at distance, whereas the eye with higher degree of myopia will promote a clear image at a near fixation distance. The risk for astigmatic anisometropia is typically defined as greater than a 1.50D difference in the cylinder component of the refraction. Against the rule astigmatism seems to be more sensitive to amblyopia development and requires longer treatment regimens with less improvement in visual acuity than with the rule astigmatism.