Preferred Retinal Locus in a Child with a Macular Retinoblastoma in the Only Eye
Kenneth P. Johnson C., MD; Aisha McLean Rubin; Aadil M. Hussain; Vasilios Papastefanou, MD, PhD; Yijun Cai; Mandeep Sagoo, MD, FRCOphth; Ashwin Reddy, MD, FRCOphth
The Royal London Hospital
Barts NHS Trust
London, United Kingdom
Introduction: Assessment of visual function of children with macular retinoblastoma has previously relied upon visual acuity. Preferred retinal loci of fixation have been identified in several retinal paediatric conditions, but not in retinoblastoma. We aim to study fixation in children with a macular tumour in their remaining eye.
Methods: Children with bilateral retinoblastoma -in whom one eye had been enucleated or had very poor vision- and a macular tumor in the other eye were enrolled. Patients underwent ophthalmic clinical examination and tested with MP-1 Microperimeter (NIDEK Technologies,Padova,Italy). Structural changes in neurosensory retina and choroid were assessed by swept source OCT.
Results: Five patients were enrolled. Only one patient successfully completed microperimetry assessment. Her vision was LogMAR 1.3 (Snellen 20/400) and was found to have a preferred retinal locus for fixation on the superior border of her macular tumour. Two patients failed to complete the examination due to high-amplitude nystagmus and other two patients did not produce reliable results.
Discussion: Though a macula-involving tumour is one of the most important factors in eyes with poor visual outcome in retinoblastoma, it is not always possible to predict visual behaviour. Microperimeters can be considered as an additional investigation for the functional assessment of the macula in cooperative children with low vision. This area presents with defined neurosensory retinal anatomy.
Conclusion: To our knowledge, this is the first time microperimetry has been used in a child with macular retinoblastoma and a preferred retinal locus identified for fixation. Applied to children with only one remaining eye, microperimetry offers clinicians a new approach in understanding the adaptive mechanisms after macular damage and may have a role in future visual rehabilitative treatments.
References: (1) Greenstein VC et al,Preferred|retinal locus in macular disease: characteristics and clinical implications. Retina. 2008 Oct;28(9):1234-40
(2)Pacella E et al, Effectiveness of vision rehabilitation treatment through MP-1 microperimeter in patients with visual loss due to macular disease. Clin|Ter. 2012 Nov;163(6):e423-8