Researchers from Philadelphia say that prophylactic use of subconjunctival antibiotics may have no impact on the rate of endophthalmitis following pars plana vitrectomy.

In the retrospective, nonrandomized, comparative case series, researchers analyzed the outcomes of 18,886 consecutive cases of transconjunctival 23-, 25-, and 27-gauge PPV over a five-year period. They examined the impact of prophylactic intraoperative subconjunctival antibiotics on the development of acute infectious postoperative endophthalmitis.

Out of all the cases, 14,068 (74.5 percent) received intraoperative subconjunctival antibiotics, and 4,818 (25.5 percent) didn’t. There were 16 cases of endophthalmitis (0.085%, 1/1,176). The incidence of endoph­thalmitis in eyes that received subconjunctival antibiotics was 0.078 percent (11/14,068 cases, 1/1,282), while the incidence in those that didn’t receive subconjunctival antibiotics was 0.10 percent (5/4,818 cases, 1/1,000). There was no statistically significant difference between the two groups (
p=0.598). Microbial culture was performed in 11 cases; six were culture-positive (5/8 cases that received subconjunctival antibiotics and 1/3 cases that did not).

The researchers say 
that, since prophylactic subconjunctival antibiotics weren’t associated with a significantly reduced rate of post-PPV endophthalmitis, and since there is a constant concern about emerging multidrug-resistant bacteria, routine prophylactic subconjunctival antibiotics may not be justified.
Retina 2018;38:9:1848-1855.
Weiss S, Adam M, Gao X, et al.

Facedown Position Questioned for Macular Holes 
Researchers compared clinical outcomes in eyes with macular hole managed by either facedown (FD) or no-FD (nFD) postoperative positioning protocols, as part of a prospective, randomized cohort study. 

Eighty eyes of 80 consecutive individuals with MH that underwent vitrectomy surgery with internal limiting membrane peeling and gas tamponade were included. Forty eyes of 40 individuals kept in FD position for three days after surgery were assigned to the FD group, and 40 eyes of 40 individuals with nFD positioning were assigned to the nFD group. Researchers examined macular holes with swept-source optical coherence tomography images at one day, two days, three days, two weeks, one month and three months after surgery. They compared the MH closure rate and change in best-corrected visual acuity. Below are some of the findings:

  • At postoperative day one, MHs were closed in 24 of 32 eyes with clear OCT images (75 percent) in the FD group, and 23 of 30 eyes with clear OCT images (77 percent) in the nFD group (p=0.97). 
  • At postoperative day two, MH closures were confirmed in 32 of 36 eyes (88.9 percent) in the FD group and in 31 of 33 eyes (94 percent) in the nFD group (p=0.84); results were unchanged at day three. 
  • At two weeks post-surgery, clear OCT images were acquired from all eyes in both groups, and MH closures were confirmed in 36 of 40 eyes (90 percent) in the FD group and in 37 of 40 eyes (92.5 percent) in the nFD group (p=0.91). 
  • Macular hole closures weren’t achieved in eyes still open by day three post-surgery, and no eyes with confirmed MH closures by day three had reopenings by three months. 
  • The distribution of macular configurations at three months wasn’t significantly different between the two groups (p=0.96). 
  • Researchers found no differences in improvement in best-corrected visual acuity (Early Treatment Diabetic Retinopathy Study letters gain) between the two groups at one month (p=0.22) and three months (p=0.45).
Researchers found that the nFD protocol neither delayed MH closures nor decreased the final closure rate after vitrectomy surgery. As such, they suggested that using the prone position postoperatively seems to be unnecessary for all MH repair procedures.
Retina 2018; Sep 7. [Epub ahead of print]
Zhang Y, Chen X, Hong L, et al.

Evaluating Anterior Chamber Volume With SS-OCT
Scientists assessed changes in anterior chamber volume with swept-source optical coherence tomography after cataract surgery, in addition to factors that influenced the ACV changes, as part of a prospective cohort study.

Fifty-one individuals who underwent cataract surgery were enrolled. Their ACV, anterior chamber depth and angle widths were measured with SS-OCT before, and one day, one week and one month after surgery. Scientists looked for associations between changes in ACV and posterior vitreous
detachments, and determined axial lengths. Here are some of their findings:

  • Compared with preoperative volumes, ACV increased significantly at all three postoperative time points (all p<0.001). 
  • ACV was greater at one week than one day after surgery (p<0.001). 
  • AXL and posterior vitreous detachments were significantly associated with ACV changes one day post-surgery (p=0.005). 
  • Neither PVDs nor AXL affected ACV changes between one day and one week after surgery. 
  • ACV stabilized in the first week after cataract surgery. 

The study researchers reported that absorption of irrigation fluid and balanced salt solution in the vitreous cavity contributed to ACV changes one week after surgery. Eyes with longer axial lengths and PVD tended to show less ACV changes one day after surgery.
Int Ophthalmol 2018; Sep 4. [Epub ahead of print].
Chen M, Hu H, He W, et al.

Vision Decreases May Predict Cognitive Decline
Researchers in the longitudinal, population-based Salisbury Eye Evaluation Study (conducted in Salisbury, Maryland), say that distance visual impairment appears to be associated with declining cognitive function.

The standardized size of visual acuity’s effect on the cognitive score was larger relative to the reverse effect, demonstrating that acuity is likely the driving force in these dynamic associations. 

In the study, researchers analyzed 2,520 adults aged 65 to 84 years, assessing them at baseline between September 1993 and August 1995 (round 1) and two years (round 2), six years (round 3), and eight years (round 4) later. They measured visual acuity using Early Treatment Diabetic Retinopathy Study charts, and the individual’s cognitive status was assessed using the Mini-Mental State Examination (MMSE).

Of the 2,520 participants in the study, the mean age was 73.5 ±5.1 years; 1,458 (58 percent) were women, and 666 (26 percent) were black. There were 2,240 (89 percent), 1,504 (61 percent), and 1,250 remaining participants (50 percent) in the second, third, and fourth rounds of the study, respectively, with more than half of the loss being due to the death of the participants. 

Both VA and MMSE score worsened over time. The mean biannual decline of VA was 0.022 logMAR (approximately one line during eight years; 95% CI, 0.018-0.026), and the mean biannual worsening of
MMSE score was -0.59 (95% CI, -0.64 to -0.54; both p <0.001). Worse baseline VA was associated with worse baseline MMSE score (r = -0.226; 95% CI, -0.291 to -0.16; p<0.001). The rate of worsening VA was associated with the rate of declining MMSE score (r = -0.139; 95% CI, -0.261 to -0.017; p=0.03). Statistical models indicated that VA in the previous round was associated with an individual’s MMSE score in the subsequent round (β = -0.995, p<0.001), and MMSE score in the previous round was associated with VA in the following round (β = -0.003, p<0.001). However, the standardized size of VA’s effect on MMSE score (β = -0.074; SE, 0.015; p<0.001) was larger relative to the reverse effect (β = -0.038; SE, 0.013; p<0.001), demonstrating that visual acuity is likely the driving force in these dynamic associations.

The researchers say that visual impairment measured at distance was associated with declining cognitive function both cross-sectionally and longitudinally over time, with worsening vision having a stronger association with declining cognition than the reverse. Worsening vision in older adults may be adversely associated with future cognitive functioning, the investigators concluded, and they add that maintaining good vision may be an important interventional strategy for mitigating age-related cognitive declines.  REVIEW
JAMA Ophthalmol. 2018 Sep 1;136:9:989-995
Zheng DD, Swenor BK, Christ SL, et al.