Ocular surface changes with applanation contact lens and coupling fluid use after argon laser photocoagulation in noninsulin-dependent diabetes mellitus

Diabetic corneal neuropathy and its relation to the severity of retinopathy in patients with type 2 diabetes mellitus: an in vivo confocal microscopy study

PURPOSE

To investigate corneal neuropathy and corneal nerve alterations in type 2 diabetes mellitus (DM) patients with different diabetic retinopathy (DR) status.

METHODS

A total of 87 eyes of 87 patients with DM and 28 eyes of 28 healthy control subjects were included in the study. DM patients were further classified into 3 groups: patients without DR (NDR), patients with non-proliferative DR (NPDR), and patients with proliferative DR (PDR). PDR patients were classified into 2 groups regarding having undergone retinal argon laser photocoagulation treatment (ALP). Ocular surface disease index score (OSDI), average tear break-up time (A-BUT), corneal sensitivity and cornea nerve fiber length (CNFL), cornea nerve fiber density (CNFD), and cornea nerve branch density (CNBD) of the cornea subbasal nerve plexus (SBNP) were measured using in vivo confocal microscopy (IVCM).

RESULTS

OSDI scores increased and A-BUT decreased in DM patients compared to the control group, but no significant difference was found between DM patient groups. Corneal sensitivity decreased in DM patients who developed DR, compared to both the controls and the NDR group. CNFD and CNFL decreased in NPDR and PDR patients compared to controls. CNFD and CNBD decreased in patients who had developed PDR, compared to all three groups. All IVCM parameters decreased with DR progression.

CONCLUSION

IVCM can detect early structural corneal nerve changes in diabetic patients. The presence of DM affects ocular surface parameters, especially in long-term DM patients. Corneal sensitivity loss is increased with the presence of DR. All IVCM parameters decrease with DR development and its progression.

Tear function in patients with diabetes mellitus: A systematic review and meta-analysis

PURPOSE

To examine tear function in patients with diabetes mellitus (DM).

DESIGN

Systematic review and meta-analysis.

METHOD

We searched Embase and PubMed from database inception to March 16, 2022. We included observational studies that compared tear function between patients with and without DM. Tear function was measured using invasive tear breakup time (ITBUT) and Schirmer's 1 test. Pooled results are presented as standard mean difference (SMD) with 95% confidence interval (CI) based on random-effects models.

RESULTS

We included 59 studies (7,234 eyes) comparing the tear function between patients with and without DM. This meta-analysis indicated that patients with DM had worse tear function than those without DM (ITBUT: SMD: -0.98, 95% CI: -1.27 to -0.69; Schirmer's 1 test: SMD: -0.45, 95% CI: -0.64 to -0.26), and the results remained consistent in patients with different types of DM (e.g., type 1 DM and type 2 DM) and from different ethnic backgrounds (e.g., Asian vs. non-Asian). Patients with DM under poor glycemic control had worse tear function than those of the non-DM group (ITBUT: SMD: -1.26, 95% CI: -1.86 to -0.66; Schirmer's 1 test: SMD: -0.25, 95% CI: -0.48 to -0.02), whereas there were no significant differences in tear function between patients with DM under optimal glycemic control and non-DM groups.

CONCLUSIONS

We found that patients with type 1 or type 2 DM had significantly reduced tear function. The level of tear function could be determined by glycemic control, and therefore, our findings suggest that glycemic control in patients with DM is critical for maintaining tear function.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero, identifier CRD42021250498.

Type 1 diabetes mellitus impairs diurnal oscillations in murine extraorbital lacrimal glands

PURPOSE

People with diabetes are at high risk of lacrimal gland dysfunction, but the underlying mechanism is not well understood. In this study, we determined how type 1 diabetes mellitus (T1DM) influences circadian homeostasis of the murine extraorbital lacrimal glands (ELGs).

METHODS

A T1DM animal model was established by systemic streptozotocin injection in C57BL/6J mice. After 5 weeks, ELGs were collected at 3-h intervals over a 24-h circadian cycle. Total extracted RNA was subjected to high-throughput RNA sequencing, and rhythmic transcriptional data were evaluated using the Jonckheere-Terpstra-Kendall algorithm, Kyoto Encyclopedia of Genes and Genomes pathway analysis, Phase Set Enrichment Analysis, and time series cluster analysis to determine the phase, rhythmicity, and unique signature of the transcripts over temporally coordinated expression. Additionally, mass, cell size, histology, and tear secretion of the ELGs were evaluated.

RESULTS

T1DM globally altered the composition of the ELG transcriptome. Specifically, T1DM significantly reprogrammed the circadian transcriptomic profiles of normal ELGs and reorganized core clock machinery. Unique temporal and clustering enrichment pathways were also rewired by T1DM. Finally, normal daily rhythms of mass, cell size, and tear secretion of mouse ELGs were significantly impaired by streptozotocin-induced diabetes.

CONCLUSIONS

T1DM significantly reprograms the diurnal oscillations of the lacrimal glands and impairs their structure and tear secretion. This information may reveal potential targets for improving lacrimal gland dysfunction in patients with diabetes.

Near reading speed changes after panretinal photocoagulation in diabetic retinopathy patients: a prospective study using an iPad application for the measurement of reading speed

PURPOSE

To investigate the changes in the near reading speed after panretinal photocoagulation (PRP) in diabetic retinopathy patients.

METHODS

This non-randomized, prospective, clinical study enrolled diabetic retinopathy patients who underwent PRP from January 2016 to June 2017. The near reading speed was measured before and 1 week, 1 month, and 4 months after PRP by using an iPad application for the assessment of reading speed; near best-corrected visual acuity (BCVA) and subfoveal choroidal thickness (SFCT) were also analyzed. The reading speed of age-matched healthy individuals was compared with that of diabetic retinopathy patients.

RESULTS

Forty-seven patients were enrolled in this study. The baseline near reading speed of diabetic retinopathy patients was significantly slower than that of age-matched healthy controls. The near reading speed was reduced at 1 week after PRP, but recovered at 1 and 4 months after PRP. Near BCVA showed a similar pattern after PRP. SFCT increased at 1 week after PRP and significantly decreased at both 1 and 4 months after PRP.

CONCLUSION

The near reading speed of diabetic patients was significantly slower than that of age-matched healthy controls. The speed was temporarily reduced at 1 week after PRP, potentially due to short-term impairment of parasympathetic nerve innervation.

Influence of diabetes mellitus on anterior segment of the eye

Diabetes mellitus (DM) has been emerging as one of the most serious health problems worldwide. Ocular complications of DM are currently one of the major causes of blindness in developed countries, among which diabetic retinopathy is relatively well studied and understood. However, although ocular surface complications of DM are common, diabetic complications of anterior segment of the eye, such as, cornea, conjunctiva, and lacrimal glands, are often overlooked. DM is associated with progressive damage to corneal nerves and epithelial cells, which increases the risk of anterior segment disorders including dry eye disease, corneal erosion, persistent epithelial defects, and even sight-threatening corneal ulcer. In this review, the authors will discuss the association of DM with disorders of anterior segment of the eye. Studies indicating the value of corneal nerve assessment as a sensitive, noninvasive, and repeatable biomarker for diabetic neuropathy will also be introduced. In addition, treatment modalities of anterior segment disorders associated with DM is discussed. The studies introduced in this review suggest that early and periodic screening of the anterior segment of the eye, as well as the retina, is important for the optimal treatment of DM.

Diabetic complications in the cornea

Diabetic corneal alterations, such as delayed epithelial wound healing, edema, recurrent erosions, neuropathy/loss of sensitivity, and tear film changes are frequent but underdiagnosed complications of both type 1 (insulin-dependent) and type 2 (non-insulin-dependent) diabetes mellitus. The disease affects corneal epithelium, corneal nerves, tear film, and to a lesser extent, endothelium, and also conjunctiva. These abnormalities may appear or become exacerbated following trauma, as well as various surgeries including retinal, cataract or refractive. The focus of the review is on mechanisms of diabetic corneal abnormalities, available animal, tissue and organ culture models, and emerging treatments. Changes of basement membrane structure and wound healing rates, the role of various proteinases, advanced glycation end products (AGEs), abnormal growth and motility factors (including opioid, epidermal, and hepatocyte growth factors) are analyzed. Experimental therapeutics under development, including topical naltrexone, insulin, inhibitors of aldose reductase, and AGEs, as well as emerging gene and cell therapies are discussed in detail.

Evidence-Based Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR) is the most frequent microvascular complication from diabetes and requires annual screening and at least annual follow-up. A systemic approach to optimize blood glucose and blood pressure may halt progression to severe stages of DR and obviate the need for ocular treatment. Although there is evidence of benefit from fenofibrate or intravitreous antiVEGF treatment for eyes with nonproliferative DR (NPDR), these therapies are not standard care for NPDR at this time. Some patients with severe NPDR, especially those with type 2 diabetes, benefit from early panretinal photocoagulation (PRP). Once DR progresses to proliferative DR (PDR), treatment is often necessary to prevent visual loss. PRP remains mainstay treatment for PDR with high-risk characteristics. However, intravitreous antiVEGF injections appear to be a safe and effective treatment alternative for PDR through at least two years. Vitreoretinal surgery is indicated for PDR cases with non-clearing vitreous hemorrhage and/or tractional retinal detachment.

A Controlled Study on the Correlation between Tear Film Volume and Tear Film Stability in Diabetic Patients

Purpose. To assess the tear film quantity and correlate it with the quality and stability of the tear film in diabetics and compare them to age matched controls. Introduction. Diabetes affects tear film parameters in multiple ways. Poor metabolic control and neuropathy are postulated factors. To further understand how diabetes affects tear film parameters this study was conducted. Subjects and Methods. Tear meniscus height was measured by anterior segment OCT, along with tear thinning time, a subtype of noninvasive tear break-up time, and blinking rate per minute which were all recorded for 22 diabetic patients. Correlations between these tear film parameters were studied and then compared to 16 age matched controls. Results. A statistically significant difference was found in blinking rate between the diabetic and the control group (P = 0.002), with higher blinking rate among diabetics. All tear film parameters were negatively correlated with duration of diabetes. A positive correlation was found between tear film volume and stability. Conclusion. Diabetes affects the tear film in various ways. Diabetics should be examined for dry eye signs even in absence of symptoms which may be masked by associated neuropathy. Duration of diabetes has an impact on tear film status.

Meta-analysis and review on the changes of tear function and corneal sensitivity in diabetic patients

To perform a comprehensive evaluation and comparison of tear function in diabetic and non-diabetic patients. Research related to tear function in diabetic and non-diabetic patients was gathered using PubMed, EBSCO, OVID. Two reviewers independently conducted the literature search. The quality assessment and the data extraction were performed in accordance with exclusion criteria and cross-checking. RevMan 5.1.7 software was used for the meta-analysis. The tear film break-up time was studied in eight articles with a total of 1449 samples. Through a random-effects model analysis, the combined weighted mean difference (WMD) was -4.44 [-5.87, -3.01]. The time in diabetic patients was shorter than that in the non-diabetic group (p < 0.00001). The basal tear secretion test was studied in seven articles with a total of 949 samples. The combined WMD was -3.96 [-5.70, -2.23], and the difference between the diabetic group and control group was statistically significant (p < 0.00001). The total tear secretion test was studied in five articles with a total of 921 samples. The combined WMD was -3.96 [-7.43, -0.50]. The difference between the diabetic and control groups was statistically significant (p = 0.03). The corneal sensitivity was compared in eight studies with a total of 976 samples. Through a random-effects model analysis, the standardized mean difference (SMD) was -5.14 [-6.99, -3.29]. The corneal sensitivity was lower in diabetic patients than the control group (p < 0.00001). Our study suggests that the tear functions are worse in diabetic patients compared with the control group. Moreover, patients with PDR are more predisposed to impaired tear functions.

Tear film osmolarity in patients with diabetes mellitus

PURPOSE

To compare tear film osmolarity (TFO) between patients with diabetes mellitus (DM) and normal healthy individuals.

METHODS

In this prospective case-controlled study, the TFO in 46 normal subjects (control group) and 55 patients with DM (study group) was evaluated. TFO in milliosmole (mOsm) was measured by using an auto-osmometer. The serum levels of glycosylated hemoglobin (HbA1c) and blood glucose in all participants were also measured. Mean outcome measures were TFO and its relationship with HbA1c level and duration of DM.

RESULTS

Mean TFO was 320.40 ± 21.80 mOsm/l in the study group and 308.22 ± 18.16 mOsm/l in the control group (p < 0.001). The TFO values were significantly associated with duration of DM (r = 0.476, p < 0.001), but no significant correlation was found with HbA1c level (r = 0.225, p = 0.114).

CONCLUSIONS

The study shows a significantly higher TFO in patients with DM than in the healthy controls. TFO also correlates with the duration of DM.