Abstract
Purpose::
X-linked retinoschisis (XLRS) is a hereditary vitreoretinal degeneration characterized by splitting of the retina. The purpose of this study was to evaluate retinal hemodynamic parameters and to determine whether these parameters are related to the morpholocical changes in the retina of patients with XLRS.
Methods::
Ten male patients with confirmed XLRS (mean age 38 years, range 16-68) and 7 age- and gender-matched control subjects were enrolled in the study. All patients underwent a complete ophthalmic examination, full-field ERG, and OCT. Retinal blood column diameter, blood velocity, and blood flow rate were measured in one eye of each subject using the Canon laser Doppler blood flow instrument. Results obtained from the major superior temporal veins of 8 XLRS patients were compared with those from the same vessels of the control subjects. In addition, we compared the blood flow between the superotemporal and inferotemporal retina in 5 patients in whom the major superior and inferior temporal vessels were measured.
Results::
Bilateral foveal schisis was present in 7 patients, while atrophic foveal lesions were observed in 3 older patients who did not show cystic macular changes. Four of the patients also had peripheral schisis inferiorly. Best-corrected visual acuity in the patients ranged from 20/30 to 20/100. Full-field ERG showed a reduced b/a amplitude ratio in all the patients. There was no difference in vessel diameter between XLRS patients and controls (150±17 µm vs. 142±18 µm, p=0.39). However, blood velocity was significantly lower in the patients (17.2±4.2 mm/sec) compared to controls (31.0±7.7 mm/sec, p=0.0007). Accordingly, blood flow rate was significantly reduced in the patients compared to controls (9.6±4.0 µl/min vs. 14.8±4.3 µl/min, p=0.03). Furthermore, blood flow measured in the inferotemporal quadrant was about 40% lower than in the superotemporal quadrant of the XLRS patients. In addition, a significant correlation between retinal blood flow and both foveal thickness (Rsq=0.56, p=0.03) and macular volume (and Rsq=0.58, p=0.048) was found within the patient group.
Conclusions::
Patients with XLRS showed reduced blood flow compared to controls even in the superior retina, where schisis was not observed by clinical examination. The correlation between laser Doppler results and OCT parameters indicates that patients with late stage XLRS and atrophic lesions in the macula have the lowest retinal blood flow. These results may contribute to a better understanding of the pathophysiology of X-linked retinoschisis.
Keywords: retinal degenerations: hereditary • blood supply • retina