Between sessions, symposiums, free papers and posters, the 13th Asia-Pacific Vitreo-retina Society (APVRS) 2019 annual meeting features a plethora of brand-new scientific content. For delegates short on time, or for those unable to join the meeting in Shanghai, PIE magazine has collected a highlight reel of some of the most interesting e-Posters taking center stage at APVRS.
Can excessive smartphone use damage the retina?
Light, especially blue light, has been known to cause damage to the retina – and the spectral peaks for smartphones are very similar to short-wavelength blue visible light. While the connection seems clear, there is no knowledge of ‘when’ or ‘if’ a damage threshold is reached.
In an e-Poster titled “Suspected Macular Light Damage Caused by the Excessive Use of Smartphone”, Lei Gao and co-authors present an observational case report of one patient with suspected macular light damage caused by excessive smartphone use.
The patient, a young man, presented with blurred binocular vision for 3 days – and the subnormal vision couldn’t be explained by currently known macular diseases. Doctors provided various ocular examinations, including slit lamp biomicroscopy, autofluorescence, fluorescein angiography, ICG angiography, multifocal ERG, visual evoked potentials, central visual field and OCT angioplex – all of which were unremarkable at initial presentation and at 6 months follow-up.
Dr. Gao and co-authors found that “OCT revealed subtle defects in the outer segment of fovea, which is in line with the pathological changes of chronic light injury”. In fact, the patient had been using his smartphone for 6 to 8 hours nightly, in the dark, for the past 3 years. This extensive, longtime viewing was considered to be the likely factor for his visual complaints. Following a 6-month behavioral intervention, the patient’s visual acuity (VA) was restored from 20/50 to 20/20, which was confirmed with revised OCT images.
This led the authors to conclude that “if similar reports are confirmed, it will surely have a profound impact on both the manufacturers and the consumers of the smartphone . . . especially when we are one step into the era of VR”.
Peculiar Manifestations: Looking at Dome-shaped Maculopathy
As a rare manifestation of pathological myopia, dome-shaped maculopathy or DSM, is believed to occur because of compressional forces during growth of the eyeball, along with differential thickening of the sclera. Subretinal fluid (SRF) in DSM patients has been seen as resistant to a variety of treatments – however, these patients often have stable VA despite persistent SRF.
To further report on this condition, Obuli N. and co-authors presented an e-Poster titled “Dome-shaped Maculopathy: A Retrospective Analysis”. During the analysis, the authors retrospectively reviewed 25 eyes of 14 patients with DSM (including 3 patients with unilateral DSM).
They found the mean spherical equivalent (SE) in these eyes was -3.25 + – 1.06D, with 11/25 eyes showing myopia < -3D. On SD-OCT, 11 of 25 eyes showed dome-shaped elevation in both the horizontal and vertical axis; 5 of 25 eyes had only vertical and 9 of 25 had only horizontal. The mean logMAR visual acuity of the eyes was 0.327 + – 0.305, while central macular thickness (CMT) and central choroidal thickness (CCT) were respectively 267.47 + – 117.87µm and 274.65 + – 94.86µm. This did not seem to differ significantly from the healthy population. Further, the mean logMAR VA of eyes with IS-OS disruption was 0.432 + – 0.245, which was poorer than eyes without the same, but not significantly so. The mean dome height (DH) measured between RPE and choroidoscleral complex below fovea was 520.24 + – 33.016µm. In the end, the authors concluded that “SRF associated with DSM is quite intractable to treatment, and although visual acuity may improve or stay stable over time, the macula may not become dry”.
It’s Complicated: Visual Loss after Photodynamic Therapy
While treatments like photodynamic therapy (PDT) often help maintain vision in polypoidal choroidal vasculopathy (PCV), in rare instances it can result in sudden visual loss. Dr. Chih-Chin Chuang presented a case report of this rare complication in an e-Poster called “Acute Visual Loss After Photodynamic Therapy for Polypoidal Choroidal Vasculopathy”.
The patient, a 72-year-old man with a history of cardiovascular disease, complained of the sudden onset of blurred vision in the left eye five days after receiving PDT for PCV. The patient was treated with an immediate intravitreal injection of ranibizumab and oral aspirin (100mg) once daily. After two months, the vision in the left eye improved from 20/400 to 20/25; and the reperfusion of macular choroidal vessels was noted in indocyanine green angiography (ICGA).
Dr. Chuang reported that “choroidal ischemic change, exudative maculopathy and patient’s underlying cardiovascular disease would result in subsequent visual loss after photodynamic therapy”. Therefore, to prevent complications, it’s advised to modify the settings or reduce the dose of PDT, provide aspirin to patients with cardiovascular disease, and use a combination of PDT and anti-VEGF for best outcomes in these patients.
It is Uveitis . . . or an IOFB?
Intraocular foreign bodies (IOFBs) can masquerade as uveitis for years – one such case was presented in an e-Poster titled “Intraocular Foreign Body (IOFB) Masquerading as Uveitis” by Ruchi Shrestha.
The patient was a 24-year-old male who complained of blurred vision in the left eye for 1.5 years, with flashes and floaters for 1 week. The patient had been treated for intermediate uveitis with oral and topical steroids for 1.5 years. Following clinical findings of a corneal scar and defect in his iris, the patient was finally diagnosed with an IOFB after referral to a retina clinic. The IOFB was confirmed on indirect ophthalmoscopy, brightness scan and computed tomography scan. His best corrected visual acuity (BCVA) at presentation was 6/6 in right eye and 6/24 in left eye.
The patient underwent pars plana vitrectomy, IOFB removal, endolaser and silicone oil insertion in left eye. After the silicone oil was removed, the BCVA in the left eye was 6/12. Dr. Shrestha concluded that “IOFB may masquerade as intermediate uveitis . . . and the most sensitive tool to diagnose an IOFB is computed tomography scan”. It was also noted that IOFBs should be removed as early as possible to prevent complications of endophthalmitis, retinal detachment, proliferative vitreoretinopathies and siderosis bulbi.
The ‘Lost Art’ of Scleral Buckling
With the rise and popularity of vitrectomy, scleral buckling rhegmatogenous retinal detachment (RRD) repair has taken a backseat in recent years – making it a bit of a ‘lost art’. However, the procedure does have its advantages, mainly a preserved vitreous and clear lens, when the external approach is used.
Therefore, Drs. Chi Lik Au and Kenneth Kai Wang Li presented a poster titled “Outcomes of Rhegmatogenous Retinal Detachment Repair by Scleral Buckling: 10- year Experience of a Local Eye Hospital in Hong Kong”, which reviewed cases of scleral buckling for RRD repair from 2009 to 2018 (excluding vitrectomy).
Drs. Au and Li included 135 patients, ranging in age from 8 to 78, with a mean age of 44.3. They found 48.5% eyes had multiple breaks, with the superotemporal quadrant was the most common quadrant to localize the break (55.8%).
Of the reviewed records, 71.6% of eyes underwent DACE (Drainage-Air-Cryotherapy-Explant) and 28.4% had non-drainage surgery, with a primary success rate of 89.7% and 81.5%, respectively. Myopic shift after encircling buckle was 0 to 3.5 diopters (D), with a mean of 1.7D. They found that epithelial defects were the most common (21.0%) transient postoperative complications, followed by subretinal hemorrhage over the drainage site (14.5%). Additionally, epiretinal membrane developed in 14.7% of eyes over 10 years of follow-up, with gas injection in DACE as the identifiable risk factor.
Overall, Drs. Au and Li reported that scleral buckling for RRD achieves a high anatomical and visual success. “This surgical option is useful for preservation of vitreous and clear lens, especially meaningful in young patients,” they concluded.
What time is the ‘right time’ for vitrectomy?
Although endophthalmitis is a rare complication, it can still occur – and today, there’s still much debate on the timing of treatment. To investigate, Dr. Rodger Paul and co-authors presented a poster titled “Early Vitrectomy in Endophthalmitis”, which compared visual outcomes following early versus late (or no) vitrectomy, in patients who developed endophthalmitis following intravitreal ant-VEGF injections or cataract surgery from 2014 to 2019.
The study included 316 cases of endophthalmitis; 32% received early vitrectomy, while 68% had a late or no vitrectomy. Although patients who received early vitrectomy had significantly worse presenting visual acuity (VA) (2.34 vs 1.89 logMAR, P < 0.0001) and better improvement in VA compared to those who received late or no vitrectomy (1.46 vs 1.04 logMAR, P = 0.008), there was no statistically significant difference in final VA was found between groups (0.869 vs 0.814 logMAR, P = 0.584).
The authors found that patients with worse presenting vision were selected for early vitrectomy – however, there was no difference in final VA, as compared to those who had no vitrectomy or late vitrectomy. Meanwhile, a greater improvement in VA was achieved with early vitrectomy was observed.
This led Dr. Paul and team, to conclude that “while further research is required, this data appears to be suggestive of a benefit of early vitrectomy in endophthalmitis”.
New animal model shows promise for photoreceptor regeneration in RP
Exciting new research on the possibility of protecting and regenerating photoreceptors is explored in a poster by Dr. Baoyi Liu and co-authors, titled “Non-invasive Electrical Stimulation Promotes Photoreceptor Survival and Regeneration in Mice with Inherited Photoreceptor Degeneration”.
In this study, the authors tested if electrostimulation (ES) protects photoreceptors from degeneration – and induces photoreceptor regeneration by mobilizing retinal endogenous stem cells in retinal degenerated mice.
The investigators applied transpalpebral ES or sham stimulation to mice carrying inherited retinal degeneration for 7 consecutive days at 5 minutes per day. An electroretinogram was used to test the ES effect the retinal function.
They found that a “significant increase of ERG b wave amplitude was observed at the end of the first week post-ES, and this was maintained for 4 weeks compared with the sham-stimulated eyes”. After ED, they also observed significant preservation of photoreceptors and an increase in proliferating cells in the retina.
This led the authors to conclude that “transpalpebral ES promotes neuroprotective, regenerative, and repairing potentials of the retinal cells, suggesting the exciting possibility of using non-invasive ES as a versatile tool for preventing photoreceptor degeneration, potentially reversing vision loss in patients with RP”.
Editor’s Note: Media MICE Pte Ltd, parent company and publisher of PIE magazine, is the Official Media Partner of APVRS 2019 Shanghai.
