Don L. Bremer

Amblyopia: The Normal Eye is Not Normal

When acuity was used to evaluate amblyopia in children, the amblyopic eye had decreased acuity and the nonamblyopic eye had normal acuity. However when Contrast Sensitivity Functions (CSFs) were used to evaluate amblyopia, losses in the CSF were discovered in both the amblyopic and the nonamblyopic eyes. During the course of occlusion therapy, the amblyopic eye improved in acuity and CSF and the nonamblyopic eye improved in CSF. The results suggest that the nonamblyopic eye is not normal and that the CSF provides additional information to acuity about amblyopia in children.

Levodopa and Childhood Amblyopia

A pilot study was undertaken to address the tolerance and efficacy of levodopa/carbidopa treatment for amblyopia in older amblyopic children who failed to respond to conventional occlusion therapy. Five amblyopic children, between the ages of 7 and 12 years, and two normal adults were given between 100 mg/25 mg and 400 mg/100 mg of levodopa/carbidopa, respectively, depending on body weight. A symptoms questionnaire was completed, with temperature, respiration, heart rate, and blood pressure taken periodically to assess tolerance. Blood samples were taken, via a heparin well, to assess the pharmacokinetics of levodopa, dopamine, noradrenaline, and DOPAC. Snellen visual acuity, contrast sensitivity, stereo acuity, and pattern VERs were measured periodically to assess efficacy. The results revealed a high prevalence of side effects including emesis and nausea (four of seven subjects). Pharmacokinetics revealed that maximum serum levels of levodopa occurred 30 minutes to 1 hour after drug ingestion and decreased by 50% after 2 to 4 hours. One hour after drug ingestion, Snellen visual acuity temporarily improved from an average of 20/159 to 20/83 in the amblyopic eyes. Contrast sensitivity and pattern VERs (10-minute checks) temporarily improved in both dominant and amblyopic eyes, whereas visual function remained stable in normal eyes. The improvements in visual function started to decrease 5 hours after drug ingestion. The results are discussed in the context of developing a therapeutic trial of levodopa/carbidopa for childhood amblyopia.

Pseudotumor cerebri in children receiving recombinant human growth hormone

PURPOSEnThis article represents the first report in the ophthalmology literature of an association between pseudotumor cerebri (PTC) and recombinant human growth hormone (rhGH).nnnDESIGNnNoncomparative case series.nnnPARTICIPANTSnThree children receiving rhGH for short stature with Turner syndrome, Jeune syndrome, or Down syndrome.nnnMETHODSnChildren underwent full ocular examination. After papilledema was identified, patients underwent lumbar puncture and imaging with either magnetic resonance imaging or computerized tomography. Treatment was under the guidance of the primary physician or neurosurgeon. The rhGH was discontinued in all children.nnnMAIN OUTCOME MEASURESnVisual acuity and evaluation of the optic nerve for resolution of papilledema were followed at each examination.nnnRESULTSnIn all three cases, papilledema resolved with the cessation of rhGH, and treatment with acetazolamide or prednisone. Visual acuity was unchanged in case 1, decreased by two to three lines in case 2, and was inconsistent in case 3. One child (case 2) required a ventriculoperitoneal shunt for persistent elevation of intracranial pressure.nnnCONCLUSIONnThere appears to be a causal relationship between the initiation of rhGH with the development of PTC. Children should have a complete ophthalmic evaluation if they report headache or visual disturbances. Baseline examination with routine follow-up should be instituted when children cannot adequately communicate.

Occlusion and levodopa-carbidopa treatment for childhood amblyopia

PURPOSEnThe purpose of the current study was to compare the effects of levodopa-carbidopa with and without part-time occlusion on visual function in older amblyopic children.nnnMETHODSnThirteen older amblyopic children were randomly assigned to receive or not receive part-time occlusion (3 h/day) combined with 7 weeks of oral dosing with levodopa-carbidopa (1.02 mg/0.25 mg/kg body weight three times daily). Visual acuity, contrast sensitivity, and fusion were measured at baseline; 1, 3, 5, and 7 weeks during the treatment regimen; and 4 weeks after termination of all treatment. At these same times health status was assessed with standard laboratory blood tests, physical examination, and subjective questionnaire.nnnRESULTSnFrom baseline to the follow-up test trial, both groups improved in visual acuity in the amblyopic eyes (occlusion group 20/116 to 20/76, P < .001; no occlusion group 20/90 to 20/73, P < .01) and dominant eyes (occlusion group 20/18 to 20/15, P > .05; no occlusion group 20/20 to 20/16, P < .01). The occlusion group exhibited a significant decrease in the difference in acuity between the dominant and amblyopic eyes of 1.3 lines (P < .02), whereas the no occlusion group revealed no significant effect. A comparison between groups revealed a significantly greater improvement in visual acuity in the amblyopic eye in the occlusion group compared with the no occlusion group (P = .01). In contrast, there was no significant difference between groups in terms of the change in visual acuity in the dominant eye (P = .15). Mean log contrast sensitivity in the amblyopic eye significantly improved in the occlusion group and did not significantly change in the no occlusion group. Fusion changed similarly in both groups. The improvements in visual function were maintained 4 weeks after the termination of all treatment. Adverse side effects were minimal in both groups.nnnCONCLUSIONnThe combination of levodopa-carbidopa and occlusion improves visual function more than levodopa-carbidopa alone in older amblyopic children.

Levodopa/carbidopa treatment for amblyopia in older children

The purpose of the present study is to determine how long visual function improves during levodopa/carbidopa with part-time occlusion treatment in older amblyopic children. A 7-week open clinical trial of levodopa (0.55 mg/kg, three times daily) with 25% carbidopa combined with part-time occlusion (3 hours/day), was undertaken in 15 older (mean age, 8.87 years) amblyopic children. Visual acuity, fusion, and stereo acuity were measured at baseline, at weeks 1, 3, 5, and 7 during treatment, and 6 weeks following the end of all treatment. Health status was assessed by physical examination, questionnaire, and standard laboratory tests (CHEM 20, complete blood cell count [CBC], and differential). The results revealed that visual acuity in the amblyopic eye improved for 5 weeks, from 20/170 at baseline to 20/107, then stabilized for the last 2 weeks. Visual acuity also improved in the dominant eye by 0.6 lines, from 20/19 to 20/16. At the 6-week follow up, visual acuity in the amblyopic eye remained at 20/107 (paired t = 4.78, df = 14, P < .001), a 37% improvement. Thirty-three percent of the subjects demonstrated improved fusion from baseline to the 7-week trial that was maintained at follow up (chi 2 = 3.97, P < .05). Stereo acuity did not significantly change. Physical exam (blood pressure, body temperature, respiration, heart rate) and standard laboratory tests remained normal and side effects were minimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Anterior tendon displacement of the inferior oblique for DVD

The effect of grading the anteriorization of the posterior portion of the inferior oblique muscle tendon fibers, relative to the insertion of the inferior rectus, was assessed for patients with dissociated vertical deviation (DVD). The placement of these fibers was varied dependent on the degree of preoperative DVD. The results from the graded group were compared to a group of patients with DVD that always received the same amount of anteriorization regardless of the degree of preoperative DVD. The results showed that, in general, anteriorization of the inferior obligue muscle tendon fibers to the level of insertion of the inferior rectus was an effective treatment for DVD. In addition, grading the anteriorization of the posterior portion of the inferior oblique muscle tendon fibers significantly decreased residual postoperative deviation.

Longitudinal Study of Levodopa/Carbidopa for Childhood Amblyopia

To determine the tolerability and efficacy of levodopa/carbidopa combined with occlusion therapy for childhood amblyopia, a double-masked placebo-controlled randomized longitudinal study was performed on 10 amblyopic children between 6 and 14 years of age. Subjects received, on average, 20/5 mg levodopa/carbidopa or 20 mg of placebo three times per day combined with part-time occlusion over a 3-week period. Visual function was assessed by Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity charts and by contrast sensitivity. Tolerability was assessed by questionnaire, SMAC (standard laboratory tests; consists of a chem 20 and complete blood count [CBC]) analysis, and physical examination. Compliance with occlusion and capsule consumption were assessed by questionnaire and by capsule count, respectively. At the end of the dosing regimen, the levodopa/carbidopa group significantly improved in visual acuity by 2.7 lines and in mean contrast sensitivity by 72% in the amblyopic eye. The placebo group improved in visual acuity by 1.6 lines in the amblyopic eye. Tolerability and occlusion compliance were similar between groups; however, capsule ingestion compliance was significantly lower in the levodopa/carbidopa group. One month after the termination of treatment, the levodopa/carbidopa group maintained a significant 1.2-line improvement in visual acuity and 74% improvement in contrast sensitivity in the amblyopic eye. The placebo group did not maintain an improvement in visual acuity between the eyes. It is concluded that levodopa/carbidopa, at an average of 0.48/0.12 mg/kg, is well tolerated and, when combined with part-time occlusion, is efficacious in improving visual function in amblyopic children.

The Contrast Sensitivity Function and Childhood Amblyopia

We measured contrast sensitivity function and visual acuity in both eyes of strabismic and anisometropic amblyopic patients. There was a linear relationship between contrast sensitivity function and visual acuity in the amblyopic eye. As visual acuity decreased, the contrast sensitivity function decreased along the contrast sensitivity axis, and peak sensitivity shifted to lower spatial frequencies. After patching therapy, when visual acuity reached 20/20 in each eye, suggesting that the amblyopia was cured, there continued to be statistically significant difference in the contrast sensitivity functions between the eyes. The contrast sensitivity function from the previously amblyopic eye was depressed compared to the nonamblyopic eye. A comparison between patients with strabismic and anisometropic amblyopia showed that, when matched for visual acuity, the contrast sensitivity functions were similar for both the nonamblyopic and amblyopic eyes. However, a large difference was found between the amblyopic and nonamblyopic eyes of each group.

Surgical Treatment of the Upshoot and Downshoot in Duanes' Retraction Syndrome

The upshoot and downshoot that occurs when the eye is rotated into the adducted position in Duanes retraction syndrome is believed to be related to a taut or leash effect from the lateral rectus muscle. When the eye is adducted, the lateral rectus muscle is believed to slip over the globe producing this abnormal movement. Five patients with Duanes retraction syndrome demonstrated this finding and underwent a splitting of the lateral rectus into a Y configuration. All five patients demonstrated a marked improvement in their up or downshoot after surgery.

Prevalence and course of strabismus through age 6 years in participants of the Early Treatment for Retinopathy of Prematurity randomized trial

PURPOSEnTo present strabismus data for children who participated in the Early Treatment for Retinopathy of Prematurity (ETROP) randomized trial.nnnMETHODSnThe prevalence of strabismus, categorized as present or absent, was tabulated for all children with history of high-risk prethreshold retinopathy of prematurity (ROP) who participated in the ETROP randomized trial and were examined at 9 months to 6 years of age. Relationships among strabismus and demographic measures, eye characteristics, and neurodevelopmental factors were analyzed.nnnRESULTSnAmong the 342 children evaluated at 6 years, the prevalence of strabismus was 42.2%. Even with favorable acuity scores in both eyes, the prevalence of strabismus was 25.4%, and with favorable structural outcomes in both eyes the prevalence of strabismus was 34.2%. Of children categorized as visually impaired as the result of either ocular or cerebral causes, 80% were strabismic at the 6-year examination. Of 103 study participants who were strabismic at 9 months, 77 (74.8%) remained so at 6 years. Most strabismus was constant at both the 9-month (62.7%) and the 6-year examination (72.3%). After multiple logistic regression analysis, risk factors for strabismus were abnormal fixation behavior in one or both eyes (P < 0.001), history of amblyopia (P < 0.003), unfavorable structural outcome in one or both eyes (P = 0.025), and history of anisometropia (P = 0.04). Strabismus surgery was performed for 53 children. By 6 years, the cumulative prevalence of strabismus was 59.4%.nnnCONCLUSIONSnMost children with a history of high-risk prethreshold ROP develop strabismus at some time during the first 6 years of life.