Search

Vessel and perfusion densities may decrease before diabetic retinopathy appears; it is unknown whether these changes affect the contribution of vessel density to perfusion density. This was a non-experimental, comparative, prospective, cross-sectional study in non-diabetic subjects (group 1) and diabetics without retinopathy (group 2). Vessel and perfusion densities in the superficial capillary plexus were compared between groups at the center, inner, and full regions and by field (superior, temporal, inferior, nasal) using optical coherence tomography angiography. Coefficients of determination (R2) between vessel and perfusion densities were calculated to find the contribution of larger retinal vessels to perfusion density. Percent differences were used to evaluate the contribution of these vessels to perfusion density in a regression model. There were 62 participants, 31 eyes by group; vessel and perfusion densities as well as the coefficients of determination between them were lower in group 2, especially in the nasal field (R2 0.85 vs. 0.71), which showed a higher contribution of larger retinal vessels to perfusion density. The regression model adjusted to a quadratic equation. In diabetics without retinopathy the contribution of vessel density to perfusion density may decrease; a low vessel density may increase the contribution of larger retinal vessels to perfusion density.

Risk of retinal damage in open globe eye injuries increases as the zone (location of the wound vertex) is more rearward. The value of clinical exploration to assess this variable is unknown.To establish the efficacy of clinical exploration as a diagnostic test to identify the injury zone in open globe ocular trauma.Assessment of patients with open globe ocular trauma, preoperative clinical assessment of injury zone and surgical description of the wound were carried out. The proportion and 95% confidence intervals (CI) of eyes whose zone changed during surgical repair were established, and the efficacy of clinical evaluation to diagnose zone was estimated. Features of eyes with and without zone change were compared using χ(2) test.89 eyes, mean age 27.1 years. Clinically, the identified zone was I in 36 eyes (40.4%), II in 38 (31.5%) and III in 25 (28.1%); the identified zone during surgery was I in 36 eyes (40.4%), II in 43 (48.3%) and III in 10 (11.2%). Zone changed in 30 eyes (34%, 95% C.I. 24 to 44). Specificity (96%), positive predictive value (93%) and positive likelihood ratio (13.9) were high only for zone II. No feature was associated with zone change.Clinical exploration was not efficient enough to identify injury zone in open globe trauma and has low prognostic value. It is not necessary to define the injury zone at first contact; it is enough identifying properly the agent, visual function and pupil reflexes for an efficient assessment.