Evaluation of macular and optic nerve head parameters in amblyopic eyes: An optical coherence tomography study

Evaluation of retinal microcirculation alterations using OCTA in hyperopic ametropic amblyopia patients before and after treatment

PURPOSE

We aimed to compare retinal microcirculation in hyperopic ametropic amblyopia patients before and after treatment and in healthy children using optical coherence tomography angiography (OCTA), and to explore the pathogenesis of hyperopic ametropic amblyopia.

METHODS

Eighteen patients with hyperopic ametropic amblyopia aged 4-8 years were selected as the patient group, and 18 age-matched healthy children were randomly selected as controls. The foveal avascular zone (FAZ) area, perimeter and circularity, vessel density (VD) and perfusion density (PD) of macular superficial retinal capillary plexus, macular thickness, peripapillary retinal nerve fiber layer thickness, and ganglion cell-inner plexiform layer thickness were compared between both groups. After 6 months of amblyopia treatment, the same parameters were measured again.

RESULTS

The VD and PD in the central, inner, inner nasal, and inner inferior regions in hyperopic ametropic amblyopia were lower than in the control group after adjustment for axial length. After 6 months of treatment, the VD increased significantly, except in the outer nasal and outer inferior regions. The PD in the central (p < 0.001), inner superior (p = 0.001), inner inferior (p = 0.011) and inner temporal (p = 0.026) regions increased. The FAZ perimeter and circularity significantly differed between the groups. After 6 months of treatment, the FAZ area and perimeter decreased, but circularity increased.

CONCLUSION

Hyperopic ametropic amblyopia eyes showed a significant decrease in vessel and perfusion densities. After amblyopia treatment, the vessel and perfusion densities of patients with hyperopic ametropic amblyopia increased, suggesting that abnormalities in the microvascular system are a pathogenic factor of amblyopia.

Optic Nerve Structural and Functional Changes in LHON-Affected and Asymptomatic Maternal Relatives: Association with H and HV Mitochondrial Haplogroups

Leber Hereditary Optic Neuropathy (LHON) affects a minority of carriers of causative mitochondrial DNA mutations. We investigated a cohort of patients with LHON, including m.11778G>A, m.3460G>A, m.14484T>C and DNAJC30 c.152A>G variants, and their asymptomatic maternal carrier relatives for additional potential associations with vision loss. We assessed visual acuity, optical coherence tomography (OCT) of the peripapillary retinal nerve fibre layer (RNFL), visually evoked potential including P-100 latency, and full mitochondrial genome sequencing. Comparison was made with a reference standard for OCT; European Descent, Heidelberg Engineering ©; and electrophysiology measurements with in-house normative ranges. RNFL was thinned overall in LHON patients (n = 12); median global RNFL −54 μm in the right eye (RE) and −50 μm in the left eye (LE) versus normal, and was found to be normal overall in asymptomatic carriers at +1 μm RE and −2 μm LE (n = 16). In four asymptomatic carriers there was RNFL thinning found either unilaterally or bilaterally; these cases were associated with isolated delay in P-100 latency (25%), delay and reduced visual acuity (50%), or reduced visual acuity without P-100 latency delay (25%). Optic nerve dysfunction was associated with mitochondrial haplogroup H and HV, versus non-H haplogroups, in the asymptomatic carriers (Fisher’s exact test, p = 0.05). Our findings suggest that optic nerve abnormalities may be identified in asymptomatic LHON mitochondrial mutation carriers, which may be associated with optic nerve dysfunction. For asymptomatic carriers these findings were associated with mitochondrial haplogroup H and HV.

Evaluation of Macular Ganglion Cell-Inner Plexiform Layer in Children with Deprivational Amblyopia Who Underwent Unilateral Cataract Surgery

Background and Objectives: The aim of the study is to assess macular ganglion cell and inner plexiform layer (mGCIPL) thickness in deprivational amblyopic eyes (AE), fellow non-amblyopic eyes (FE) and normal eyes (NE) using spectral. domain optical coherence tomography (SD-OCT). Materials and Methods: Twenty two children (64% boys) who underwent surgical removal of unilateral congenital or developmental cataracts and exhibited visual impairment despite postoperative visual rehabilitation were included in the study. Cataract surgery was performed in patients aged 55.82 ± 35.85 months (range 6 to 114 months). The mean age of the study group was 9.73 ± 2.85 years (range 5 to 15 years). The comparison group consisted of 22 healthy age- and gender-matched children. The best corrected visual acuity (BCVA) after surgery was: 0.75 ± 0.27 (range 0.3 to 1.3) in AE, 0.1 ± 0.13 (range 0 to 0.5) in FE and 0.04 ± 0.07 (range 0 to 0.2) in NE. OCT scans were performed in all patients and subsequently corrected for axial length related magnification errors. Results: The average thickness of mGCIPL was 70.6 ± 11.28 μm in AE; 77.50 ± 6.72 μm in FE and 81.73 ± 5.18 μm in NE. We found that mGCIPL was statistically significantly thinner in deprivation AE compared to FE (p = 0.038) and NE (p = 0.0005). The minimum thickness of mGCIPL was respectively: 62.68 ± 13.2 μm, 70.3 ± 7.61 μm, and 74.5 ± 5.47, and also differed between AE and FE (p = 0.023) and AE and NE (p = 0.0004). Also, measurements in the inferior, inferotemporal, and superotemporal sectors showed thinning of mGCIPL in AE compared to NE. Conclusions: This analysis may suggest that deprivational amblyopia caused by unilateral congenital or developmental cataract in children may be associated with mGCIPL thinning.

The iridocorneal angle and related anterior segment structures in pediatric anisohyperopic amblyopic eyes

Objectives:

We aimed at investigating the iridocorneal angle, anterior segment structural differences, and their relationship in pediatric anisohyperopic amblyopic eyes.

Methods:

This study was designed as an observational case-control study. We prospectively evaluated the pediatric patients who were newly diagnosed with hyperopic anisometropic amblyopia. Iridocorrneal angle in four sectors, axial length, and anterior segment structures were compared to emmetropic fellow and control eyes using Pentacam and IOLMaster 700 devices. The anisohyperopia and iridocorneal angle related factors were determined in hyperopic anisometropic amblyopic eyes.

Results:

Forty-three hyperopic anisometropic amblyopic eyes, 43 fellow eyes, and 44 control eyes were included. The mean axial length, anterior chamber volume, and anterior chamber depth were significantly reduced in the study eyes compared to the fellow (p < 0.001, p = 0.021, and p = 0.045, respectively) and control eyes (p < 0.001, p = 0.001, and p = 0.009, respectively). The average iridocorneal angle was significantly lower in the study eyes than in the fellow and control eyes (p < 0.001 and p = 0.018, respectively). The iridocorneal angle correlated with anterior chamber depth (r = 0.49, p = 0.013), anterior chamber volume (r = 0.42, p = 0.038), the anterior radius of curvature (r =−0.54, p = 0.005), the posterior radius of curvature (r =−0.58, p = 0.002), and lens thickness (Rho =−0.41, p = 0.033) in the study eyes. Anisohyperopia was related to the interocular difference in axial length (Rho = 0.53, p = 0.005), anterior chamber depth (Rho = 0.53, p = 0.005), and anterior chamber volume (Rho = 0.42, p = 0.031).

Conclusion:

Pentacam and IOLMaster 700 are suitable for non-contact imaging of iridocorneal angle and anterior segment structures in the pediatric age. These biometric differences and their relationship should be kept in mind whenever anterior or posterior segment surgery is planned for pediatric anisohyperopic amblyopic eyes.