Retinopathy of prematurity (ROP) was first described in 1942 under the name retrolental fibroplasia. ROP occurs because the retinal vessels and neural retina of a preterm newborn are incompletely developed at birth and do not grow normally.
It is one of the leading preventable causes of childhood blindness, especially in high- and middle-income countries. Retinal imaging in infants with retinopathy of prematurity (ROP) has become increasingly important for diagnosis, documentation, and treatment guidance.
Ultra-wide-field imaging systems have brought about improvements in the management of ROP. The development of ultra-widefield retinal imaging has accelerated our understanding of common retinal diseases. They are useful for visualizing and documenting retinal features and determining ROP type.
As we continue to validate the diagnostic and prognostic significance of pathology in the retinal periphery, the ability to visualize and evaluate these features in an efficient and patient-friendly manner will become more important.
Current interest in ultra-widefield imaging includes the development of potential biomarkers of disease progression and indicators of preclinical disease development.
Ultra-widefield imaging has added a whole new dimension to fundus imaging in children, with up to 200° of the retina now visible, compared with the 30–50° visibility provided by standard fundus photography.
Dr. Anthony T. Moore, professor of ophthalmology at the University of California San Francisco School of Medicine, San Francisco, United States, discusses two ultra-widefield imaging systems that are also capable of fluorescein angiography (FA): the RetCam (Clarity Medical Systems), which provides 120–130° of view, and the Optos (Optos Inc.), providing 200° visibility.
The RetCam, a contact lens-based system, requires pupillary dilatation and clear media. Although imaging can be performed in awake preterm infants or neonates, older children must be sedated.
“The RetCam images are available in real-time but the resolution is low,” Dr. Moore noted. “The system has video capability and is particularly useful for FA in the operating room [OR].”
The Optos is a confocal dual-laser system that can be used in awake patients of any age with or without pupil dilatation. “This system is ideal for use in a clinic setting. In a pediatric ophthalmology practice, it can be used in young infants using a ‘flying baby’ technique with or without using a speculum,” he said.
“A disadvantage is the lack of real-time imaging. It has a useful fundus autofluorescence [FAF] mode and FA and Indocyanine Green angiography capabilities.” However, Dr. Moore noted the importance of having a highly skilled technician when using this instrument.
The RetCam system, Dr. Moore pointed out, has revolutionized the care of patients with retinopathy of prematurity (ROP) and retinoblastoma. Many institutions are currently using telemedicine for ROP screening in remote areas.
It is also useful in patient consultations for children with suspected nonaccidental injury and in situations requiring careful documentation of retinal findings, such as viral retinitis. He described the case of a 14-month-old boy who presented with leukocoria in the right eye. The left fundus appearance was normal.
During an examination in the OR, a diagnosis of Coats disease was made and FA was performed using the RetCam in video mode, which allowed the full extent of the retinovascular abnormalities to be identified and treated.
Repeat imaging 7 months after laser treatment indicated a good response to treatment with no further vascular leakage; retinal detachment had been prevented. The Optos widefield system was used in the case of a 5-month-old boy.
The mother was a carrier of the RS1 gene so the patient was at 50% risk of being affected. The technician imaged the fundus without using a speculum using her fingers to hold the lids apart. The retinal findings were abnormal, with a silvery reflex toward the periphery.
The use of the zoom function showed the typical foveal schisis seen in this disorder. The Optos FAF mode is also useful for identifying abnormalities of the retinal pigment epithelium and retina. Dr. Moore also noted the case of bear track retinopathy in a 7-year-old boy; the pathology was very well highlighted in FAF mode.
In the case of a 15-year-old girl who presented with a sudden onset of floaters in the right eye, indirect ophthalmoscopy showed an abnormality in the extreme periphery, which would have been difficult to image with a normal camera; however, widefield FA clearly showed a small area of non-perfusion in the left eye and peripheral non-perfusion and neovascularization in the right eye.
This resulted in a diagnosis of familial exudative vitreoretinopathy treated with laser in the right eye. The technology can be used to monitor disease progression. Dr. Moore commented on the non-mydriatic mode of Optos:
“It is useful in children who are drop-phobic, as an alternative to annual dilated fundus examination in patients with stable strabismus and normal vision, and as a fundus examination for use in parents to identify suspected inherited eye diseases”.
An illustrative example is that of a 10-year-old boy with blurred vision referred for an inpatient consult. He had previously undergone a failed stem-cell transplant. He was drop-phobic, and he and his father refused the instillation of drops.
Optos imaging showed bilateral disc swelling and a macular star. The boy was diagnosed with idiopathic intracranial hypertension and was followed with regular Optos imaging without the use of eye drops.