Researchers looked at the relationship between longitudinal changes in macular vessel density and ganglion cell complex, and central visual field, in early glaucoma eyes via optical coherence tomography-angiography and OCT.
The observational cohort included 95 eyes, 37 preperimetric and 58 with early glaucoma (24-2 VF mean deviation≥-6 dB), with an average follow-up of 3.8 years. A total of 5.3 visits were included.
Whole image (wiVD and wiGCC) and parafoveal scans, as well as localized regions of interest (LROI), hemiretinas of whole image; and superior, inferior, temporal and nasal sectors of parafoveal maps, were matched with central VF locations. Age-adjusted rates of change of vessel density, GCC, mean sensitivity (MS) of VF locations and 10-2 vessel density MD were calculated with linear-mixed-effect models. Normalized rates of change were calculated to compare change rates in wiVD and wiGCC.
Main outcome measures included structure-function correlations between vessel density/GCC and central VF measurement change rates, and comparisons between the correlations of SF relationships after bootstrapping the difference of the correlations.
Here are some of the findings:
- Vessel density loss and GCC thinning demonstrated significant correlations with central VF damage, globally and with most LROIs.
- The SF correlation (r=0.42; CI, 0.24 to 0.58) between wiVD and 10-2 VF MD change rates was 0.27; CI, 0.08 to 0.45 between wiGCC and 10-2 VF MD changes rates, all p<0.05.
- In contrast to GCC thinning, vessel density loss in the parafoveal sectors demonstrated significant correlations with central VF damage in inferior and temporal sectors.
- Differences between the SF relationship with central VF damage weren’t significant between vessel density loss and GCC thinning.
- The mean of normalized change rates of wiVD -7.40; CI, -7.71 to 7.09 percent/year) was faster than wiGCC (-1.95; CI, -2.21 to -1.70 percent/year); p<0.05.
Researchers wrote that rates of vessel density loss and GCC thinning were associated with central VF loss over time. They suggested that assessment of macular vessel density and GCC thickness should be considered for evaluation of glaucoma progression.
Ophthalmol Glaucoma. June 13, 2022. [Epub ahead of print].
Mohammadzadeh V, Moghimi S, Nishida T, et al.
Retinal Sensitivity in CSC
Investigators predicted changes in retinal sensitivity using optical coherence tomography in eyes with central serous chorioretinopathy.
Twenty-three eyes in 23 patients with CSC were enrolled. Retinal sensitivity was measured twice using microperimetry in all examined eyes. Spectral-domain OCT measurements were simultaneously conducted. The relationship between retinal sensitivity and the thicknesses of the following metrics were investigated in a pointwise manner, and the associations between the change in retinal sensitivity and OCT parameters at baseline were assessed:
- retinal nerve fiber layer plus the ganglion cell layer (RNFL + GCL);
- inner nuclear layer (INL);
- outer nuclear layer (ONL); and
- serous retinal detachment height (SRDH)
The mean age of participants was 49.8 ±10.7 years. Here are some of the findings:
- The mean SRDH was significantly lower (p<0.001) and the mean retinal sensitivity (p<0.001) was significantly higher at the second exam compared with the first; however, the logMAR visual acuity didn’t differ significantly between the two exams (p=0.063).
- The logMAR VA was associated with retinal sensitivity at the first and second exams (p<0.001).
- The retinal sensitivity at the second exam was significantly correlated with retinal sensitivity, RNFL + GCL, INL, ONL and SRDH at the first exam and improvement in SRDH.
Investigators wrote that retinal sensitivity was associated with the retinal structure in eyes with CSC and that these parameters could be useful for predicting changes in visual function prior to treatment.
Graefes Arch Clin Exp Ophthalmol. June 4, 2022. [Epub ahead of print].
Kanda S, Zhou HP, Inoue T, et al.
Pupilloperimetry Technique May Predict Alzheimer’s
A new study found that dendrites of melanopsin-containing retinal ganglion cells may be affected at preclinical disease stages.
A study recently investigated whether machine learning has the potential to identify subjects at high risk of developing the condition.
The study included 125 participants (45 to 71 years old) with a family history of Alzheimer’s and consequently at higher risk of disease development. In addition, 61 age-similar participants with no family history of the disease were included as controls.
The technological test used in the study is called chromatic pupilloperimetry, which measures the pupil light reflex for 54 small (0.43-degree) dim and bright red and blue light stimuli presented at a 30-degree visual field. This allows the examination of the rod-, cone- and melanopsin-mediated pupil light reflex at various retinal locations, the researchers say. After testing each participant, a machine learning-based model was used to analyze the results.
The investigators say that chromatic pupilloperimetry-based machine learning models were highly discriminative in differentiating subjects with and without a family history of Alzheimer’s disease using transient pupil light reflex for focal red (primarily cone-mediated) and dim blue (primarily rod-mediated) light stimuli.
The research team also noted that features associated with transient pupil response latency achieved an area under the receiver operating characteristic curve of 0.90 for the left eye and 0.87 for the right eye (1.00 equals a perfect correlation).
The researchers say that the test targets most discriminative of a positive Alzheimer’s family history in response to dim blue light were located in the periphery of the 24-degree visual field, particularly in the temporal side (nasal side of the retina),” they explained. In addition, in the right eye, the mean pupil response latency for dim blue light in the two most discriminative visual field targets in the temporal visual field was significantly shorter in individuals with a family history of the disease compared with those without. A similar trend was noted in the left eye but didn’t reach clinical significance.
In regard to dim red light stimuli, the researchers noted that they detected discriminative test targets throughout the retina with no specific pattern.
Although this data suggests contraction latency parameters may be predictive of high risk for Alzheimer’s disease, larger and longer studies will need to evaluate the ability of this modality to forecast actual disease development, the researchers say.
Sci Rep. June 15, 2022. [Epub ahead of print].
Lustig-Barzelay Y, Sher I, Sharvit-Ginon I, et al.
Analyzing DALK and PK For Keratoconus
Scientists reported demographic and clinical characteristics for U.S. patients with keratoconus undergoing deep anterior lamellar keratoplasty or penetrating keratoplasty, and complication rates for the two procedures.
They performed a retrospective review of 2010 to 2018 health records for patients with keratoconus who were younger than 65 using the IBM MarketScan Database. A multivariable model adjusting for potential confounders was used to determine factors associated with receiving DALK over PK. Rates of complications 90 days and one year postoperatively were calculated. For select complications only (repeat keratoplasty, glaucoma surgery and cataract surgery), Kaplan-Meier survival curves were additionally constructed over a period of up to seven years.
A total of 1,114 patients with keratoconus (mean age: 40.5 ±12.6 years) were included in the report’s analysis. Here are some of the findings:
- A total of 119 received DALK, and 995 received PK.
- Regional differences existed, with patients in the north central United States having greater odds of receiving DALK than northeastern patients (OR=5.08, CI, 2.37 to 10.90).
- Rates of endophthalmitis, choroidal hemorrhage, infectious keratitis, graft failure, graft rejection, postoperative cataract, glaucoma or retinal surgery were all low at 90 days for DALK and one year for PK.
- Complication rates for DALK and PK were both low—beyond one year for repeat keratoplasty, cataract and glaucoma surgery.
Scientists found regional differences between DALK and PK utilization rates although complication rates in this nationally representative sample were low at one year and beyond. However, they added, further studies would be needed to assess whether longer-term complications differ by procedure type.
Cornea. May 26, 2022. [Epub ahead of print].
Mgboji G, Varadaraj V, Thanitcul C, et al.