23 Ago ULTRA-WIDE FIELD RETINOGRAPHY IN RETINAL DETACHMENT
Rhegmatogenous retinal detachment (RRD) is defined as the separation of the neurosensory retina from the underlying retinal pigment epithelium by the formation of a retinal tear or hole.
Identification and closing of all these holes have been the basic principles of treatment, so properly locating the tears is key to success.
Depending on their location with respect to the equator, retinal tears are divided into anterior or posterior ones.
Where is the equator of the retina?
The equator is located just behind the last division of the retinal vessels and just in front of the vortex veins (figure 1).
The anterior tears (the most frequent) are located in front of the equator, along the posterior limit of the base of the vitreous.
Early detection of anterior tears is crucial because missed retinal breaks are responsible for up to 64% of cases of failed RRD surgery.
A posterior tear will appear behind this bifurcation and usually corresponds to a pathological vitreoretinal adhesion behind the base of the vitreous.
Dilated fundus exam (DFE) with scleral depression remains the gold standard for diagnosis of peripheral retinal lesions, although generally in our daily clinical practice it is not usually performed because it requires a retina specialist, a good pupil dilation and active patient collaboration (it is a procedure quite uncomfortable). Further, following the procedure, it is advisable to draw all the clinical findings, which is time-consuming, especially in the era of electronic medical records.
For a few years now, wide field and ultra-wide field (UWF) imaging devices are available.
Our study compared the findings between DFE (without scleral depression), UWF retinography using an Optos 200Tx (Optos PLC, Dunfermline, Scotland, UK) in the primary position of gaze (PPG) without mydriasis and the intraoperative findings on the day of surgery (within 24h-48h after DFE and UWF imaging) in 123 patients with primary RRD.
Overall, in 96.7% of the patients retinal breaks were found during surgery compared to 73.2% (p<0.001) as assessed by DFE and 65% (p<0.001) as assessed by UWF fundus imaging (no significant differences were detected between UWF imaging and DFE).
Anterior retinal tears were identified in 74% of the patients based on intraoperative examination, compared with 45.5% when assessed by funduscopic examination (p<0.001) and 39% when assessed by Optos (p<0.001).
Assuming that intraoperative examination detected all the retinal tears, Optos performed in PPG missed 47.3% and DFE missed 38.5% of anterior retinal breaks.
Posterior retinal tears were detected in 28.5% of patients during surgery, 29.3% when assessed by DFE and 30.9% when assessed by Optos. No significant differences were found between the three techniques.
Retinal breaks observed in the intraoperative exam followed Lincoff rules in 70.5% of the cases.
Regarding the extent and location of the RRD there were no differences between the three techniques.
So, what are the advantages of UWF Retinography?
UWF Retinography allows us to simultaneously evaluate in detail the central and peripheral retina (200º), with high resolution and the images are obtained in less than half a second and in a single shot, mydriasis is not required, and in addition the findings can be easily documented for clinical, teaching, or legal purposes. In our results we found that there were no differences between DFE and UWF imaging regarding the location of anterior retinal tears.
In conclusion, UWF retinography precisely documents the RRD extent, helps us in the surgical planning, saves time, and also helps us in the follow-up of RRD patients, although is suboptimal compared with intraoperative findings for the detection of anterior tears when performed in PPG.
We recommend that in order to increase the location of the anterior tears, the gaze should be positioned towards the location of the RRD; maybe this would be a good study for the future.
We leave you the link to our full article:
Dr. Beatriz Abadía/Dr. Pilar Calvo