Comparison of Cirrus spectral domain OCT with disc-macula distance to disc diameter ratio in diagnosing congenital optic nerve hypoplasia.

PURPOSE: Diagnosis of congenital optic nerve hypoplasia (CONH) can be challenging in children or uncooperative individuals. Misdiagnosis can lead to inappropriate treatment; thus, it is important to identify an objective and reliable measurement. The purpose of this study was to evaluate whether Cirrus spectral domain optical coherence tomography (SD-OCT) is a valid test for diagnosing CONH by comparing it to the disc-macula distance to disc diameter (DM:DD) ratio. METHODS: A total of 93 participants (64 controls and 29 CONH) underwent comprehensive eye examinations, fundus photography and Cirrus SD-OCT. Receiver operating characteristic (ROC) curves for the DM:DD ratio and OCT disc area were constructed for CONH and control eyes. RESULTS: Mean (±SD) OCT disc area was 1.46 (±0.42) mm2 and 1.89 (±0.38) mm2 for CONH and control eyes, respectively (p < 0.0001). The area under the curve for the DM:DD ratio was 0.97 (95% confidence interval: 0.91-0.99) and 0.79 for OCT disc area (95% confidence interval: 0.70-0.86), which were significantly different (p = 0.0005). The optimal cut-off value for OCT disc area was 1.66 mm2 (76% sensitivity, 70% specificity), while the optimal cut-off for DM:DD ratio was 3.10 (85% sensitivity and 95% specificity). The Cirrus SD-OCT showed a tendency to overestimate disc size, especially in cases with no light perception (NLP) or segmental CONH. CONCLUSIONS: Although the DM:DD ratio is superior to OCT in diagnosing CONH with a higher sensitivity and specificity, the ratio is subject to inter-examiner variability and can be challenging to obtain. We found the Cirrus SD-OCT to be a valid objective test for diagnosing CONH. Caution is advised when using SD-OCT in segmental CONH or in an eye with NLP. We suggest 1.66 mm2 as the optimal cut-off value for Cirrus SD-OCT disc area to differentiate a hypoplastic from a normal optic disc.

Contrast sensitivity of amblyopic eyes in children with myopic anisometropia.

BACKGROUND: Contrast sensitivity function (CSF) in amblyopes has been studied extensively, with few studies on amblyopia associated with myopic anisometropia. The purpose of this study was to investigate CSF of amblyopic eyes in children with myopic anisometropia compared to fellow eyes of the amblyopic children, as well as to control subjects with high myopia but no amblyopia. METHODS: Twenty amblyopic children with myopic anisometropia (range of visual acuity in the amblyopic eye: 6/10 to 6/100) and 16 control subjects with high myopia (< -6.00 D) but no amblyopia were recruited. CSF with linear sine-wave gratings was assessed at 1.5, 3, 6, 12 and 18 cycles per degree (cpd) in the amblyopic, fellow and control myopic eyes. Multivariate analysis of variance was used to compare logCS of the amblyopic, fellow and control myopic eyes after adjusting for age and race. RESULTS: The average degree of myopia in the amblyopic eyes was -10.46 D (range: -5.00 to -18.25 D). The average degree of myopia in the right eyes of control subjects was -8.61 D (range: -6.25 to -13 D). A statistically significant difference was found in logCS among the three groups of eyes at all frequencies (p < 0.001) except at 1.5 cpd. CSF of amblyopic eyes was statistically significantly lower than that of control myopic eyes at 3, 6, 12 and 18 cpd but not at 1.5 cpd. No significant difference in logCS was found between control myopic and fellow eyes. The co-variates (age and race) were not significantly related to the logCS (p > 0.05). Reduced CSF of the amblyopic eyes at the middle frequencies was associated with the degree of anisometropia. CONCLUSION: CSF at the middle and higher frequencies was reduced in the amblyopic eyes associated with myopic anisometropia compared to the fellow eyes of the same amblyopic children as well as to eyes of control subjects with high myopia but no amblyopia.

Comparison of Heidelberg Retina Tomograph with disc-macula distance to disc diameter ratio in diagnosing optic nerve hypoplasia.

PURPOSE: To evaluate whether Heidelberg Retinal Tomograph (HRT) is a valid test for diagnosing congenital optic nerve hypoplasia (CONH) compared to the ratio of the distance between the centre of the optic disc and the centre of the macula and the mean optic disc diameter (DM:DD ratio). Furthermore, to determine the optimal cut-off value of HRT disc area to differentiate a hypoplastic disc from a normal optic disc. METHODS: A total of 33 subjects with CONH (4-67 years old) and 160 normal subjects (5-65 years old) were recruited and underwent comprehensive eye examinations, fundus photography and HRT. Receiver operating characteristic curves for DM:DD ratio and HRT disc area were constructed based on data from the 46 CONH eyes and 160 control eyes. RESULTS: Mean (±S.D.) HRT disc area was 1.94 (±0.54) mm(2) for the control eyes and 0.84 (±0.35) mm(2) for the CONH eyes (p < 0.0001). The area under the curve (AUC) for DM:DD ratio was 0.83 (95% confidence interval: 0.76-0.90). The AUC for HRT disc area was 0.96 (95% confidence interval: 0.94-0.99). A statistically significant difference was found between AUC for HRT disc area and that for DM:DD ratio (p = 0.0004). The optimal cut-off value for HRT disc area was 1.42 mm(2) with 95% sensitivity and 85% specificity. The optimal cut-off value for DM:DD ratio was 3.20 with 78% sensitivity and 78% specificity. CONCLUSIONS: Both HRT and the DM:DD ratio are valid tests to aid diagnosis of CONH. HRT is superior to DM:DD ratio in diagnosing CONH with higher sensitivity and specificity. We suggest the optimal cut-off value for HRT disc area as 1.42 mm(2) in order to discriminate a hypoplastic disc from a normal optic disc.

Association of refractive error with optic nerve hypoplasia.

PURPOSE: To evaluate the association of refractive error with optic nerve hypoplasia (ONH). METHODS: A total of 30 ONH subjects were recruited and underwent comprehensive eye exams. Refractive error data from this group was compared to data from a group of 3232 non-ONH subjects from the same facility. Spherical equivalent was calculated to assess refractive error. Multiple logistic regression was used to evaluate the relationship between ONH and refractive error while controlling for age, race, and gender. RESULTS: The prevalence of hyperopia (≥+1.00 D), myopia (<-0.75 D), and anisometropia (≥1.00 D) was higher in ONH subjects than in controls. ONH subjects were 9.1 times more likely to be hyperopic than emmetropic (OR = 9.1, 95% CI = 2.9-28.4, p < 0.001) and 3.8 times more likely to be myopic than emmetropic (OR = 3.8, 95% CI = 1.2-11.5, p = 0.02). Unilateral ONH subjects were 10.0 times more likely to have anisometropia than controls (OR = 10.0, 95% CI = 3.9-25.6, p < 0.0001). Bilateral ONH subjects were 3.8 times more likely to have anisometropia than controls (OR = 3.8, 95% CI = 1.1-12.7, p = 0.03). CONCLUSIONS: Optic nerve hypoplasia subjects were more likely than control subjects to exhibit significant refractive errors, particularly hyperopia. Anisometropia tended to be more likely to occur in subjects with unilateral ONH than in bilateral ONH. Based on our findings, we recommend that clinicians perform a comprehensive eye examination on all patients with ONH and prescribe for existing refractive error when visual acuity or general visual function can realistically be improved.

Effect of Amblyopia Treatment on Macular Thickness in Eyes With Myopic Anisometropic Amblyopia.

PURPOSE: To determine whether abnormal macular thickness in myopic anisometropic amblyopia differed after amblyopia treatment. Furthermore, to investigate whether effect of treatment on macular thickness was associated with subject age or improvement in stereoacuity. METHODS: Seventeen children (mean age: 9.0 [±3.0] years, ranging from 5.7-13.9 years) with myopic anisometropic amblyopia (visual acuity [VA] in amblyopic eyes: 20/80-20/400) were recruited and treated with 16-week refractive correction, followed by an additional 16-week refractive correction and patching. Macular thickness, best-corrected VA, and stereoacuity were measured both before and after amblyopia treatment. Factorial repeated-measures analysis of variance was performed to determine whether macular thickness in amblyopic eyes changed after amblyopia treatment. RESULTS: Mean baseline VA in the amblyopic eye was 1.0 ± 0.3 logMAR and improved to 0.7 ± 0.3 after amblyopia treatment (P < 0.0001). The interaction between eye and amblyopia treatment was statistically significant for average foveal thickness (P = 0.040). There was no treatment effect on fellow eyes (P = 0.245); however, the average foveal thickness in the amblyopic eye was significantly reduced after amblyopia treatment (P = 0.049). No statistically significant interactions were found for the other macular thickness parameters (P > 0.05). CONCLUSIONS: Abnormal central macula associated with myopic anisometropic amblyopia tended to be thinner following amblyopia treatment with no significant changes in peripheral macular thickness.

A case of amblyopia with contralateral optic nerve hypoplasia.

We describe an unusual case of unilateral optic nerve hypoplasia (ONH) in a patient with contralateral anisometropic/strabismic amblyopia. A seven-year-old boy presented with visual acuities of 6/12 R and 6/18 L and eccentric fixation in the left eye. Cycloplegic retinoscopy was R +1.50/-0.50 × 180 and L +5.25 DS. Funduscopy revealed optic nerve hypoplasia of the right eye. The patient fixated with his better-seeing right eye, despite the optic nerve hypoplasia. His reduced vision may be attributed to optic nerve hypoplasia in the right eye and amblyopia in the left. Although optic nerve hypoplasia can occur with ipsilateral amblyopia, we believe this is the first reported case of unilateral optic nerve hypoplasia in the fellow eye of an amblyopic patient.

Vision therapy management for dissociated horizontal deviation.

PURPOSE: Dissociated horizontal deviation (DHD), a rare subtype of strabismus, is a change in horizontal eye alignment that does not obey Hering's law. The variation is unrelated to a change in accommodation and depends on which eye is fixating. Both esotropia (ET) and exotropia (XT) can manifest in the same patient with DHD. Surgery has been reported to manage DHD, but often a second or third surgery is necessary. We report two cases of DHD that were managed with vision therapy (VT). CASE REPORTS: Case one: A 9-year-old girl presented for eye examination with her parents noting an eye drifting out. Cover test showed a DHD that varied from 15Δ left ET to 15Δ alternating XT. A 40Δ XT manifested when she was inattentive. Antisuppression, vergence, accommodation, and oculomotility were addressed with VT. Upon completion of VT, binocular vision functions were normal except for appreciation of global stereopsis. No strabismus was observed during the examination. These findings were stable at a 7-month follow-up visit. Case two: A 40-year-old man presented for eye examination with the complaint of double vision and eye strain. Cover test revealed a DHD that varied from 5Δ ET to 15Δ XT, along with DVD. A 30 to 40Δ XT was observed during visual inattention. Antisuppression and vergence skills were addressed with VT. At the end of VT, most binocular vision functions were normal. No strabismus was observed on cover test. Follow-up examination 16 years later showed no strabismus by cover test, although XT manifested when he was inattentive. CONCLUSIONS: In two DHD cases, control of eye alignment improved with VT. To the best of our knowledge, these are the first case reports to describe management of DHD with VT. Eye care practitioners should be aware that a long period of VT may be necessary to successfully manage DHD.

A prospective pilot study of treatment outcomes for amblyopia associated with myopic anisometropia.

OBJECTIVES: To determine the efficacy of refractive correction alone and patching treatment with near activities on amblyopia associated with myopic anisometropia in children aged 4 to less than 14 years. The associations of visual acuity (VA) improvement with age,degree of anisometropia, patching compliance, presence of strabismus, and presence of eccentric fixation were also investigated. METHODS: Seventeen amblyopic children were recruited(range of VA in the amblyopic eye, 20/80 to 20/400). Visual acuity was assessed at 4, 8, 12, and 16 weeks while participants wore spectacles and/or contact lenses for full refractive correction. Patching treatment was initiate dat the 16-week visit. The primary outcome was VA after 16 weeks of refractive correction alone and final VA after 16 weeks of patching. RESULTS: The mean (SD) baseline VA in the amblyopiceye was 0.96 (0.27) logMAR, which improved to a mean(SD) of 0.84 (0.24) logMAR with refractive correction and to a mean (SD) of 0.71 (0.30) logMAR after the addition of patching (P.001). Comparing the final VA with the baseline VA, we found that VA improvement averaged 2.59 lines. The final VA in the amblyopic eye was associated with the baseline VA in the amblyopic eye(P.001), the magnitude of anisometropia (P.001),and the level of patching compliance (P=.04). The improvement in VA with patching was inversely associated with participants' age (P=.03) and presence of eccentric fixation (P=.02). CONCLUSION: Both refractive correction and patching significantly improved the VA of the amblyopic eye associated with myopic anisometropia, with 88% of participants' eyes improving 2 lines or more. Further improvement in VA was observed when patching plus near activities was added to refractive correction and patients were followed for 16 more weeks. We recommend that clinicians treat myopic anisometropic amblyopia with refractive correction and patching plus near activities.

Comparison of fixation disparity measured by saladin card and disparometer.

PURPOSE: The purpose of this study was to compare the fixation disparity (FD) measurements taken with the Saladin Near Point Balance Card (Saladin card) to those made with the Sheedy Disparometer, and to determine if the same clinical norms used with the Disparometer can be applied to the newer Saladin card. METHODS: Subjects were 44 optometry students (aged 23 to 34 years) without strabismus, amblyopia, or asthenopia during near work. They were randomized to begin at one of three examiners' stations: dissociated near phoria using Modified Thorington card; FD with Saladin card; and FD with Disparometer. Subjects proceeded to each station in turn. FD was measured for each subject through forced vergence demands of 0, 3, 6, and 9 base-in (BI), and 3, 6, 9, 16, and 20 base-out (BO), alternating BI and BO demands. Examiners were masked to subjects' results from the other stations. RESULTS: FD curve (FDC) types were the same with the two instruments in most cases. However, statistically significant differences were found for FDC slopes (p = 0.048), y intercepts (p < 0.0001), and FD values through BI prisms (p < 0.0001), with the Disparometer finding the FD to be more eso/less exo than did the Saladin card. FD values through BO prisms showed no statistically significant differences but great variability. CONCLUSIONS: The two instruments generally produce similar types of FDCs. However, the Disparometer tends to yield more eso/less exo FD measurements compared with the Saladin card. Although the newer Saladin card frequently produces FDC slopes and y intercepts within the expected range (as published for the Disparometer) for asymptomatic subjects, slopes and y intercepts obtained by the Saladin card are not sufficiently similar to those obtained by the Disparometer to warrant use of the same norms. Further study is needed to establish appropriate norms for the Saladin card.

A prospective study of macular thickness in amblyopic children with unilateral high myopia.

PURPOSE: To compare macular thickness of the normal fellow eye to that of the amblyopic eye using optical coherence tomography (OCT) in children with unilateral high myopia. Relationships between macular thickness and magnitude of myopic anisometropia, axial length, and visual acuity (VA) were investigated. METHODS: Thirty-one children with a mean age of 9.56 years were recruited. Macular thickness, axial length, best-corrected VA, and refraction were measured. Paired t-test was performed to compare the macular thickness of the amblyopic eye to that of the fellow eye. Partial correlations were used to test the relationships between interocular difference in macular thickness and anisometropia, axial length, and VA. RESULTS: Average (± SD) LogMAR VA in the amblyopic eye was 0.96 ± 0.31. Mean spherical equivalent in amblyopic eyes was -10.79 ± 3.40 diopters. A statistically significant difference in macular thickness was found between amblyopic and fellow eyes, with amblyopic eyes having greater foveal thickness but reduced inner and outer macular thickness. Only the nasal outer macular thickness had a statistically significant association with the magnitude of anisometropia. CONCLUSIONS: Amblyopic children with unilateral high myopia tend to have a thicker fovea and thinner inner and outer macula in the amblyopic eye compared to the normal fellow eye. The findings indicate that anatomic changes may be present in the retinas of amblyopic children with unilateral high myopia. Future study is warranted to determine whether the mechanism of the macular changes is due to high myopia, amblyopia, or a combination of the two.

A prospective study of different test targets for the near point of convergence.

PURPOSE: To determine whether different test targets including an accommodative target (AT), a transilluminator (TR), and a transilluminator with a red lens (RL), affect the near point of convergence (NPC) value; and to determine which test target is most sensitive to identify convergence insufficiency (CI) in young adults. METHODS: Subjects were 36 optometry students from the Illinois College of Optometry, including 18 subjects with normal binocular vision (control group) and 18 subjects with CI. None of the subjects had accommodative insufficiency. The NPC break and recovery were measured by three methods: AT, TR, and RL. Each test method was administered by a different examiner and the test sequence was randomized. RESULTS: The mean NPC break values for AT, TR, and RL in the control group were 4.31, 3.76, and 4.08 cm respectively, compared to 10.05, 11.37 and 13.04 cm in the CI group. The mean recovery values were 6.23, 5.56, and 5.95 cm for AT, TR, and RL respectively in the control group, vs 12.21, 14.37, 16.40 cm in the CI group. Significant differences in NPC break and recovery values were detected in the CI group between RL and AT, but not between AT and TR, or TR and RL. There was no significant difference in NPC values using the three targets in the control group. For an NPC cut point of 6 cm (break) and 9 cm (recovery), RL had higher sensitivity (100%) and specificity (88.9%) as well as lower false positive (10%) and false negative (0%) values compared to AT. CONCLUSION: NPC with RL is a more sensitive method to identify abnormal findings and assist in diagnosing CI compared to using AT or TR. We recommend that NPC with RL be routinely used to evaluate patients suspected of having CI.

Value of the Heidelberg Retinal Tomograph in optic nerve hypoplasia.

PURPOSE: A case of optic nerve hypoplasia (ONH) is reported to demonstrate the value of the Heidelberg Retinal Tomograph II (HRT) in assisting with the diagnosis. CASE REPORT: An 8-year-old black male was referred to our clinic for evaluation of right esotropia and presumed amblyopia. Best-corrected visual acuities were 20/60 OD (right eye) and 20/25 OS (left eye). Cover test showed constant right esotropia, measuring 10 at distance and 16 at near. A smaller optic nerve head was detected OD with absence of the double ring sign. The findings of HRT were consistent with a diagnosis of unilateral ONH, with a disc area of 1.545 mm OD vs. 2.527 mm OS. DISCUSSION: The clinical features, management, and associations of ONH are discussed. CONCLUSION: HRT is a useful tool to assist in diagnosis of ONH by physically measuring the optic nerve.

A case of primary congenital glaucoma: a diagnostic dilemma.

BACKGROUND: Primary congenital glaucoma generally presents with a classic clinical triad of photophobia, blepharospasm, and epiphora caused by the corneal changes that occur secondary to increased intraocular pressure (IOP). The condition typically presents bilaterally and is rarely hereditary. Onset is from age 2 months to 2 to 3 years. CASE REPORT: A 2-year, 5-month-old Hispanic boy presented with an enlarged right eye and an intermittent right exotropia, without tearing or photophobia. Examination also found high myopia and an optic nerve cup-to-disc ratio larger in the right than the left eye. Referral to a pediatric ophthalmologist was initiated. On the first examination under anesthesia (EUA), the child was diagnosed with unilateral megalocornea with a normal IOP. He did not have any other typical signs and symptoms of primary congenital glaucoma. An EUA 8 months later led to a diagnosis of primary congenital glaucoma based on the new appearance of Haab's striae, further enlargement of the cornea, and an elevated IOP. At this point, medical management was instituted. CONCLUSION: This case shows the importance of recognizing signs of primary congenital glaucoma so that appropriate management can begin as soon as possible to provide the best visual outcome for a child.

Accommodative and vergence difficulties interfering with image clarity through a binocular indirect ophthalmoscope.

PURPOSE: This study sought to identify accommodative and vergence deficiencies that could explain why some students have difficulty seeing clearly when using a binocular indirect ophthalmoscope (BIO) containing its standard +2.00 D lenses. METHODS: A survey was distributed to Illinois College of Optometry 3rd- and 4th-year students. Based on the information supplied by the survey, students were divided into two groups: those who are unable ("BIO plano") and those who are able ("BIO plus") to obtain a clear image with the +2.00 D lenses in their BIO's. Forty-seven subjects participated: 22 in the BIO plano group and 25 in BIO plus group. Two of the authors, masked to subject group, measured all subjects' accommodative amplitudes and facilities, monocular estimation method (MEM) retinoscopy, negative relative accommodation and positive relative accommodation (NRA/PRA), distance and near vergence ranges, distance and near phorias, Worth 4-dot test, and near point of convergence (five times). RESULTS: The Mann-Whitney U analysis of numerical data for the two groups showed a statistically significant difference for accommodative facility in the right eye (p = 0.004). The difference between the two groups approached significance for accommodative facility with both eyes (p = 0.02), facility in the left eye (p = 0.03), distance base-out blur (p = 0.02), near base-out break (p = 0.02), and near base-out recovery (p = 0.04). For all findings in which the difference between the two groups was significant or approached significance, the BIO plus group had higher median values. When subjects were classified by difficulty with the plus side of the flippers during accommodative facility testing, there was a statistically significant difference with both eyes (Fisher exact test, p = 0.003) and with the right eye (p = 0.008) between the BIO plus and BIO plano groups. When subjects were classified by the presence or absence of an accommodative or binocular vision syndrome, categorical data analysis showed the difference between the two groups approached significance, with more BIO plano subjects having syndromes (p = 0.03). CONCLUSION: No one test absolutely defined who would have difficulty with the +2.00 D lenses in the BIO. There are several skills required; less developed plus acceptance and convergence may cause difficulties.

Nearpoint of convergence: test procedure, target selection, and normative data.

BACKGROUND: The purpose of this study was to help determine the most appropriate target to be used for the assessment of the nearpoint of convergence, normative data for the break and recovery in adults, and the diagnostic value of the red-glass modification and repetition of the nearpoint of convergence. METHODS: A total of 175 subjects with normal binocular vision and 38 subjects with convergence insufficiency were evaluated. The nearpoint of convergence was measured three ways, with an accommodative target, a penlight, and a penlight with red and green glasses. The nearpoint of convergence was also measured using a penlight for 10 repetitions. RESULTS: Results suggest a clinical cutoff value of 5 cm for the nearpoint of convergence break and 7 cm for the nearpoint of convergence recovery with either an accommodative target or a penlight with red and green glasses. CONCLUSION: This study establishes normative data for the nearpoint of convergence break and recovery in the adult population and supports the value of various test modifications when other testing is equivocal.