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Liasis A, Franco E, Eldib A, Handley S, Scanga HL, Nischal KK. The influence of congenital corneal opacity on ERGs obtained using an abbreviated protocol. Ophthalmic Genet 2023; 44:6-10. [PMID: 36541570 DOI: 10.1080/13816810.2022.2149817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Visual electrophysiology may be used to assess visual potential in infants with congenital corneal opacities (CCO). It is essential to recognize confounding effects from these opacities on the flash electroretinogram (ERG). METHODS ERGs were recorded in awake children employing skin electrodes placed at the lower eyelid crease, both referred to a midfrontal electrode (Fz). A hand-held stimulator was used to present a mixed rod-cone and a dim white stimulus. Recordings were carried out before and after penetrating keratoplasty (PK), when performed. RESULTS Five infants under the age of 12 months with visually significant CCO were evaluated. In all cases, initial ERGs employing the mixed rod-cone stimulus showed well-defined a-wave with reduced amplitude b-wave. Reduction of stimulus intensity resulted in an increase in the b-wave and normalization of the b:a ratio from 1.1 (range 0.7 to 1.3) to 2.8 (range 1.5 to 4.3). In three cases who underwent PK, the postoperative ERGs recorded with a mixed rod-cone stimulus were normal in waveform shape with a mean b:a ratio of 2.0 (range 1.7 to 3.0). CONCLUSION Selective reduction of the scotopic bright flash ERG b-wave is typically caused by retinal dysfunction that is post-phototransduction or inner retinal. In infants with CCO, scotopic ERGs to bright flashes can show a reduced b:a ratio that improves or normalizes either after PK or stimulus intensity reduction. The study highlights that media opacity can contribute to the generation of an ERG with reduced b-wave in the absence of inner retinal dysfunction.
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Affiliation(s)
- Alkiviades Liasis
- Division of Paediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.,Istituto Internazionale per la Ricerca e Formazione in Oftalmologia (IRFO), Italy
| | - Elena Franco
- Division of Paediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.,Department of Translational Medicine, University of Ferrara, Ferrara, Italy.,Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Amgad Eldib
- Division of Paediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.,Istituto Internazionale per la Ricerca e Formazione in Oftalmologia (IRFO), Italy
| | - Sian Handley
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Hannah L Scanga
- Division of Paediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Ken K Nischal
- Division of Paediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.,UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.,University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Nischal KK, Naor J, Jay V, MacKeen LD, Rootman DS. Clinicopathological correlation of congenital corneal opacification using ultrasound biomicroscopy. Br J Ophthalmol 2002; 86:62-9. [PMID: 11801506 PMCID: PMC1770954 DOI: 10.1136/bjo.86.1.62] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To investigate the correlation between clinical, high frequency ultrasound biomicroscopy (UBM) and, where possible, histological findings in cases of congenital corneal opacification presenting to the departments of ophthalmology, Great Ormond Street Hospital for Children, London, and the Hospital for Sick Children, Toronto, Canada. METHOD 22 eyes of 13 children (age range 3-225 days) with congenitally opaque corneas were examined. UBM was performed using the ultrasound biomicroscope (Allergan-Humphrey). All eyes underwent penetrating keratoplasties (PKP) except five. The host corneas were all sent for histological examination. RESULTS The final diagnosis in our series was Peters' anomaly in nine cases (70%), corneal dystrophy in two cases (15%), and sclerocornea in two cases (15%). The UBM findings changed the clinical diagnosis in five cases (38%). In these five cases histology was available in four and confirmed the UBM diagnosis in each case. In no case of the 13 where histology was available did it contradict the UBM findings. In two cases a hypoechoic region in the anterior stroma was seen on UBM which correlated histologically with absent Bowman's layer and oedema. In two cases UBM revealed aniridia and in one, congenital aphakia, which was not apparent clinically. CONCLUSION UBM examination is not only very useful in evaluating the clinical diagnosis in congenital corneal opacification, it also acts as a preoperative guide in cases undergoing PKP by detecting keratolenticular and iridocorneal adhesions and other ocular abnormalities such as aniridia and congenital aphakia. In all cases where PKP was performed the UBM diagnosis was confirmed histologically. The clinical diagnosis was incorrect in five cases. This has important implications in studies of phenotype/genotype correlation of congenital corneal opacification.
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Affiliation(s)
- K K Nischal
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Trust, London, UK.
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