Browsing by Subject "Visual Acuity"
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Item Local Variations in Rod Function and Subretinal Drusenoid Deposits (SDD) in Patients with Reticular Pseudodrusen (RPD)(2017-01-17) Kiser, Kelly; Daniels, Tad; Csaky, Karl; Birch, David; Wang, Yi-ZhongPURPOSE: Reduced rod sensitivity and slowed dark-adaptation are common in age-related macular degeneration, especially in those patients with reticular pseudodrusen (RPD). The unique fundus appearance in RPD is thought to be caused by subretinal drusenoid deposits (SDDs). In this prospective study, we evaluate the relationship between local variations in rod function and local variations in SDD thickness. METHODS: This study included one eye from each of six patients ages 59-89 with a best corrected visual acuity of 20/32 or better and one eye from each of 4 age-similar volunteers with healthy retinas. Following 30 minutes of dark adaptation, a 56 point macular scotopic sensitivity map was generated using short-wavelength, spot size 3 stimuli on a Nidek MP-1S fundus perimeter. For each patient, 8-12 roughly equidistant test points 4-8 degrees from the fovea were selected to represent areas of high and low scotopic sensitivity. Patients were exposed to a bright light for 3 minutes (80% bleach), and then these points were tested every 5-10 minutes over the course of 1.5-2 hours. SLO infrared images and SD-OCT volume scans (96 lines, 20*20 degrees), were acquired on a Heidelberg Spectralis imaging platform. Segmentation with manual adjustment was used to delineate the combined thickness of RPE and SDD. Segmentation results were then processed by a MATLAB routine to obtain the average RPE/SDD thickness of the 1 degree local area centered at each test location. RESULTS: The lowest sensitivity in the rod field was located in regions showing RPD on SLO fundus images, and correlated with RPE/SDD thickness (R2=0.21911). During dark adaptation, the time needed to gain 5 dB in sensitivity relative to the maximum luminance (recovery time) was longer in patients (mean=44.8 min) than in normals (mean=3.6 min, p<0.0001) and there was a significant correlation between SDD thickness and recovery time (R2=0.38135). DISCUSSION: Our results show that there are two separable consequences of SDD. One is to reduce dark-adapted sensitivity and the other is to substantially delay recovery from a bleaching light.Item Visual Outcomes after Intraocular Foreign Body Injuries at Parkland & UT Southwestern Hospitals and Clinics(2024-01-30) Mohan, Navnit; Ashkenazy, NoyBACKGROUND: Intraocular foreign bodies (IOFBs) make up a large portion of open globe injuries and can cause severe vision loss. IOFBs entrapped in the posterior segment are a particularly significant cause of greatly diminished visual acuity and legal blindness (VA<20/200), prompting analysis of the factors that may influence visual outcomes. OBJECTIVES: The purpose of our study is to determine how surgical approach (single vs. staged surgical repair) may affect visual outcomes for patients with traumatic posterior segment IOFB injuries. We also examine whether patients presenting with specific vision-threatening sequelae are more or less likely to undergo a specific surgical approach. Additionally, we record incidence data on different IOFB material types, mechanisms of injury, and the use of safety glasses. METHODS: This is a retrospective chart review with a target population of patients 18-85 years old who were surgically treated for traumatic posterior segment IOFB injuries at Parkland and UT Southwestern from 6/1/2011 to 5/23/2023. 53 patient records accessed through Epic Systems met inclusion criteria. 12 patients underwent single surgical repair and 41 underwent staged repair, suggesting a hospital/ systemwide preference in surgical approach. RESULTS: Our results did not find a significant difference between initial visual acuity (t-stat=-0.953, p=0.288), final visual acuity (t stat=-1.075, p=0.297), or change in visual acuity (t-stat=0.056, p=0.954) between single and staged repair groups. Among 19 different vision-threatening sequelae examined, patients presenting with scleral laceration (p=0.0378) and vitreous hemorrhage (p=0.0245), were significantly more likely to undergo staged surgical repair, while those presenting with endophthalmitis (p=0.0073) were more likely to undergo single surgical repair by Fisher's exact test. The IOFB material types were metallic (89%), glass (7%), and stone (4%). Hammering was the most common mechanism of injury, accounting for 30.2% of cases. Data on safety glasses use was available for 20 patients, amongst whom 25% affirmed and 75% denied use. CONCLUSIONS: Our data suggest a predominance of IOFBs of metallic origin and a skew towards staged surgical repair for patients at Parkland & UTSW hospitals and clinics. The poor use of safety glasses within the data collected underscores the necessity of emphasizing eye protection in metal work and other high-risk occupations. Given the small sample size of our study, more data may help better elucidate visual outcome differences based on repair type and provide further insight into specific sequelae that increase the likelihood of a particular surgical approach.