In patients with chiasmal compression, PERG amplitude and OCT thickness measurements were significant related to VF loss, but not to each other. OCT and PERG quantify neuronal loss differently, but both technologies are useful in understanding structure-function relationship in patients with chiasmal compression. (ClinicalTrials.gov number, NCT00553761).

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Spondylometaphyseal dysplasia with cone-rod dystrophy is a rare autosomal-recessive disorder characterized by severe short stature, progressive lower-limb bowing, flattened vertebral bodies, metaphyseal involvement, and visual impairment caused by cone-rod dystrophy. Whole-exome sequencing of four individuals affected by this disorder from two Brazilian families identified two previously unreported homozygous mutations in PCYT1A. This gene encodes the alpha isoform of the phosphate cytidylyltransferase 1 choline enzyme, which is responsible for converting phosphocholine into cytidine diphosphate-choline, a key intermediate step in the phosphatidylcholine biosynthesis pathway. A different enzymatic defect in this pathway has been previously associated with a muscular dystrophy with mitochondrial structural abnormalities that does not have cartilage and/or bone or retinal involvement. Thus, the deregulation of the phosphatidylcholine pathway may play a role in multiple genetic diseases in humans, and further studies are necessary to uncover its precise pathogenic mechanisms and the entirety of its phenotypic spectrum.

The analytic framework for fundus findings proposed in this study seems reproducible and useful, because the severity categories do correlate with retinal function as measured by full-field ERG. This system may allow more precise exchange of information between practitioners as well as researchers with regard to identifying patients with greater retinal compromise rapidly as well as in comparison of outcomes of different treatment regimens.

PurposeThe aims of this study are to compare optical coherence tomography (OCT)-measured macular retinal layers in eyes with permanent temporal hemianopia from chiasmal compression and control eyes; to compare regular and slow-flash multifocal electroretinography (mfERG) in patients and controls; and to assess the correlation between OCT, mfERG, and central visual field (SAP) data.MethodsForty-three eyes of 30 patients with permanent temporal hemianopia due to pituitary tumors who were previously submitted to chiasm decompression and 37 healthy eyes of 19 controls were submitted to macular spectral domain OCT, mfERG, and 10-2 SAP testing. After segmentation, the thickness of the macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer, and photoreceptor layer (PRL) was measured. Amplitudes and oscillatory potentials (OPs) were measured on regular and slow-flash mfERG, respectively, and expressed as the mean values per quadrant and hemifield.ResultsRNFL, GCL, and IPL thickness measurements were significantly reduced in all quadrants, whereas INL, OPL, and PRL thicknesses were significantly increased in the nasal quadrants in patients compared to those in controls. Significant correlations between OCT and 10-2 SAP measurements were positive for the RNFL, GCL, and IPL and negative for the INL, OPL, and PRL. OPs and mfERG N1 amplitudes were significantly reduced in the nasal hemiretina of patients. Significant correlations were found between OP and mfERG amplitudes for inner and outer nasal hemiretina OCT measurements, respectively.ConclusionPatients with permanent temporal hemianopia from previously treated chiasmal compression demonstrated significant thinning of the RNFL, GCL, IPL, and thickening of the INL, OPL, and PRL associated with reduced OP and mfERG N1 amplitudes, suggesting that axonal injury to the inner retina leads to secondary damage to the outer retina in this condition.