Ophthalmic and clinical factors that predict four-year development and worsening of diabetic retinopathy in type 1 diabetes

To investigate the role of ophthalmic imaging markers - namely retinal thickness measures and corneal nerve morphology - in predicting four-year development and worsening of diabetic retinopathy (DR) in type 1 diabetes (T1DM).126 eyes of 126 participants with T1DM were examined at baseline and after four years. Diabetic retinopathy (DR) was graded using the Early Treatment Diabetic Retinopathy Study scale. HbA1c, nephropathy, neuropathy, cardiovascular factors, and retinal thickness using optical coherence tomography (OCT) and corneal nerve fiber length (CNFL) using corneal confocal microscopy at baseline were assessed by univariate and step-wise multiple logistic regression, and their diagnostic capabilities for single and combined measures.Four-year development of DR was 19% (13 of 68 without DR at baseline). Worsening of DR was seen in 43% (25 of 58 with DR at baseline). When adjusted for potential confounders, a lower CNFL (AUC=0.637, p=0.040, 64% sensitivity and 64% specificity at 14.9mm/mm(2) cut-off), higher triglycerides (AUC=0.669, p=0.012, 64% sensitivity, 62% specificity at 0.85mmol/L) and an elevated vibration threshold (AUC=0.708, p=0.002, 96% sensitivity, 40% specificity at 3.55Hz) were significant predictors for four-year worsening of DR.Reduced CNFL, elevated vibration perception threshold and higher triglycerides can predict future worsening of DR

Morphometric Stability of the Corneal Subbasal Nerve Plexus in Healthy Individuals: A 3-Year Longitudinal Study Using Corneal Confocal Microscopy

PURPOSE. We examined the age-dependent alterations and longitudinal course of subbasal nerve plexus (SNP) morphology in healthy individuals. METHODS. Laser-scanning corneal confocal microscopy, ocular screening, and health and metabolic assessment were performed on 64 healthy participants at baseline and at 12-month intervals for 3 years. At each annual visit, eight central corneal images of the SNP were selected and analyzed using a fully-automated analysis system to quantify corneal nerve fiber length (CNFL). Two linear mixed model approaches were fitted to examine the relationship between age and CNFL, and the longitudinal changes of CNFL over three years. RESULTS. At baseline, mean age was 51.9 6 14.7 years. The cohort was sex balanced (v 2 ¼ 0.56, P ¼ 0.45). Age (t ¼ 1.6, P ¼ 0.12) and CNFL (t ¼ À0.50, P ¼ 0.62) did not differ between sexes. A total of 52 participants completed the 36-month visit and 49 participants completed all visits. Age had a significant effect on CNFL (F CONCLUSIONS. The CNFL showed a stable course over a 36-month period in healthy individuals, although there was a slight linear reduction in CNFL with age. The findings of this study have implications for understanding the time-course of the effect of pathology and surgical or therapeutic interventions on the morphology of the SNP, and serves to confirm the suitability of CNFL as a screening/monitoring marker for peripheral neuropathies

Longitudinal assessment of corneal subbasal nerve morphology as a potential measure of diabetic peripheral neuropathy

This thesis represents a significant step forward in developing a validated measure for diabetic peripheral neuropathy – a debilitating and prevalent complication of diabetes. The candidate investigated corneal nerve structure in healthy people as well as in type 1 diabetic individuals in a 4-year longitudinal study. The outcomes of stability of the corneal small nerve fibre in healthy people and evidence of significant decline in diabetic individuals with peripheral neuropathy over time provide justification for the ongoing efforts to establish corneal nerve structure as an objective and appropriate adjunct to conventional measures of peripheral neuropathy

Effect of ocular hypotony secondary to cyclodialysis cleft on corneal topography

PURPOSE: To report the changes in corneal topography in 2 cases of ocular hypotony induced by cyclodialysis cleft after blunt trauma, which were successfully treated by argon laser photocoagulation. METHODS: For both patients, a full ophthalmic clinical examination and corneal topography were performed before and after argon laser cleft closure. RESULTS: In the first case, the corneal topography showed 3.81-D astigmatism at 96 degrees, which was reduced to 1.1 D at 124 degrees 1 week after treatment and 0.66 D at 122 degrees at 3 weeks after treatment. In the second case, the corneal astigmatism was 3.91 D at 104 degrees, which decreased to 1.44 D at 104 degrees and 0.35 D at 118 degrees at 1 week and 4 months after treatment, respectively. CONCLUSIONS: In both cases, the with-the-rule astigmatism reduced significantly after successful closure of the cleft and an increase in intraocular pressure

Cone location and correction of keratoconus with rigid gas-permeable contact lenses

Purpose To evaluate the influence of cone location and corneal cylinder on RGP corrected visual acuities and residual astigmatism in patients with keratoconus. Methods In this prospective study, 156 eyes from 134 patients were enrolled. Complete ophthalmologic examination including manifest refraction, Best spectacle visual acuity (BSCVA), slit-lamp biomicroscopy was performed and corneal topography analysis was done. According to the cone location on the topographic map, the patients were divided into central and paracentral cone groups. Trial RGP lenses were selected based on the flat Sim K readings and a ‘three-point touch’ fitting approach was used. Over contact lens refraction was performed, residual astigmatism (RA) was measured and best-corrected RGP visual acuities (RGPVA) were recorded. Results The mean age (±SD) was 22.1 ± 5.3 years. 76 eyes (48.6%) had central and 80 eyes (51.4%) had paracentral cone. Prior to RGP lenses fitting mean (±SD) subjective refraction spherical equivalent (SRSE), subjective refraction astigmatism (SRAST) and BSCVA (logMAR) were −5.04 ± 2.27 D, −3.51 ± 1.68 D and 0.34 ± 0.14, respectively. There were statistically significant differences between central and paracentral cone groups in mean values of SRSE, SRAST, flat meridian (Sim K1), steep meridian (Sim K2), mean K and corneal cylinder (p-values < 0.05). Comparison of BSCVA to RGPVA shows that vision has improved 0.3 logMAR by RGP lenses (p < 0.0001). Mean (±SD) RA was −0.72 ± 0.39 D. There were no statistically significant differences between RGPVAs and RAs of central and paracentral cone groups (p = 0.22) and (p = 0.42), respectively. Pearson's correlation analysis shows that there is a statistically significant relationship between corneal cylinder and BSCVA and RGPVA, However, the relationship between corneal cylinder and residual astigmatism was not significant. Conclusions Cone location has no effect on the RGP corrected visual acuities and residual astigmatism in patients with keratoconus. Corneal cylinder and Sim K values influence RGP-corrected visual acuities but do not influence residual astigmatism

Research update: LANDMark study: Longitudinal assessment of neuropathy in diabetes using novel ophthalmic MARKers

The eye is a simple, non-invasive location for screening, diagnosing and follow up of diabetic peripheral neuropathy

Research update: LANDMark study: Longitudinal assessment of neuropathy in diabetes using novel ophthalmic MARKers

The eye is a simple, non-invasive location for screening, diagnosing and follow up of diabetic peripheral neuropathy

Optical coherence tomography predicts 4-year incident diabetic neuropathy

Abstract Purpose To examine the capability of optical coherence tomography-derived retinal thickness measures in detecting 4-year incident diabetic peripheral neuropathy (DPN). Methods 145 eyes of 145 participants with diabetes but no DPN at baseline were examined for incident DPN. HbA1c levels, nephropathy, neuropathy (DPN), cardiovascular measures, and various retinal thickness measures were examined at baseline and after 4 years. Incidence of DPN was defined as newly developed DPN at follow-up. Baseline factors were assessed by univariate and a step-wise multiple logistic regression, and the predictors were examined for diagnostic capabilities. Results Of the 145 participants without DPN at baseline, 51 had developed DPN when examined after 4 years (35% incidence). Of the ophthalmic variables, the mean (S.D.) of the overall thickness in the parafovea at baseline was 315 (18) μm in the no DPN group and 306 (18) μm in the ‘incidence’ group, and the differences were significant, p = 0.005. The superior hemisphere parafovea (mean (S.D.): 318 (17) μm vs 310 (20) μm, p = 0.02) and inferior hemisphere parafovea (313 (19) μm vs 302 (18) μm, p = 0.002) were different in the incident DPN group compared with the no DPN group. When adjusted for age, retinal thickness in the parafovea (AUC = 0.65, p = 0.003, 86% sensitivity and 44% specificity at 321 μm criterion), and body mass index or BMI (AUC = 0.65, p = 0.003, 49% sensitivity and 83% specificity at 29.3 kg m−2 criterion) at baseline were significant predictors for 4-year incident DPN. Conclusions A lower retinal thickness at the parafovea and a higher BMI can predict 4-year incident neuropathy in patients with diabetes, with acceptable diagnostic accuracies. This OCT-derived measure may serve as a potential ophthalmic marker in the screening of patients at risk of developing DPN