Usefulness of Schirmer's tear strips and borosilicate glass tubes in chemical analysis of human tear fluid: A practical check in VEGF detection.

INTRODUCTION: Human tears contain a number of agents which may play an important role in diagnosing local eye disorders as well as systemic diseases. The small amount of fluid obtained during the collection and the consequent difficulty in analysing it are the main problems encountered in the diagnostic process. AIM: We decided to investigate the practical usefulness of two simple methods of collecting tear fluid for chemical analysis, i.e., glass tubes and Schirmer's strips. The substance analyzed was vascular endothelial growth factor (VEGF), a compound commonly recognized in ophthalmology. METHODS: We used standard Schirmer's tear test and calibrated glass tubes for tear fluid collection in healthy volunteers. The standard ELISA assay was used to check the effectiveness of the tear sampling by estimating the VEGF level. RESULTS: The results of the study show that Schirmer's tear strip test is a more effective tool of the two. Moreover, using Schirmer's strips to obtain tear fluid was found to be more patient friendly and amounts of the tear fluid collected with that test were enough and better for the VEGF detection. CONCLUSIONS: Our study indicates that the widely used Schirmer tear test may be the best method of tear collection for chemical analysis. However, further studies on test calibration are needed.

The Role of Telemedicine, In-Home Testing and Artificial Intelligence to Alleviate an Increasingly Burdened Healthcare System: Diabetic Retinopathy.

In the presence of the ever-increasing incidence of diabetes mellitus (DM), the prevalence of diabetic eye disease (DED) is also growing. Despite many improvements in diabetic care, DM remains a leading cause of visual impairment in working-age patients. So far, prevention has been the best way to protect vision. The sooner we diagnose DED, the more effective the treatment is. Thus, diabetic retinopathy (DR) screening, especially with imaging techniques, is a method of choice for vision protection. To alleviate the burden of diabetic patients who need ophthalmic care, telemedicine and in-home testing are used, supported by artificial intelligence (AI) algorithms. This is why we decided to evaluate current image teleophthalmology methods used for DR screening. We searched the PubMed platform for papers published over the last 5 years (2015-2020) using the following key words: telemedicine in diabetic retinopathy screening, diabetic retinopathy screening, automated diabetic retinopathy screening, artificial intelligence in diabetic retinopathy screening, smartphone diabetic retinopathy testing. We have included 118 original articles meeting the above criteria, discussing imaging diabetic retinopathy screening methods. We have found that fundus cameras, stable or mobile, are most commonly used for retinal photography, with portable fundus cameras also relatively common. Other possibilities involve the use of ultra-wide-field (UWF) imaging and even optical coherence tomography (OCT) devices for DR screening. Also, the role of smartphones is increasingly recognized in the field. Retinal fundus images are assessed by humans instantly or remotely, while AI algorithms seem to be useful tools facilitating retinal image assessment. The common use of smartphones and availability of relatively cheap, easy-to-use adapters for retinal photographs augmented by AI algorithms make it possible for eye fundus photographs to be taken by non-specialists and in non-medical setting. This opens the way for in-home testing conducted on a much larger scale in the future. In conclusion, based on current DR screening techniques, we can suggest that the future practice of eye care specialists will be widely supported by AI algorithms, and this way will be more effective.

Tear fluid collection methods: Review of current techniques.

Tear fluid, composed of lipid, aqueous, and mucin layers, contains electrolytes, water, proteins, peptides, and glycoproteins. Its components may serve as diagnostic indicators of local and systemic diseases. The aim of the study was to conduct literature review in order to identify the current methods of tear collection. The most commonly used method which was relatively easy to perform and allowed to obtain sufficient tear volume for further chemical and physical analysis was selected through PubMed database search for the following keywords: tear sampling, human tears, chemical analysis of tears, physical tear analysis, animal tear sampling. Final criteria of articles selection were: human tears, tear sample collection, chemical and physical analysis of tears. Time of publication of the articles not older than 1995. The analysis of 70 articles revealed that the most common tear fluid collection methods are Schirmer tear strips and capillary tubes. Thus, we recommend the use of Schirmer strips and microcapillary tubes as the cheapest and easiest methods for sampling of tear fluid for further chemical analysis.

How to measure retinal microperfusion in patients with arterial hypertension.

PURPOSE: Assessment and monitoring of changes in microcirculatory perfusion, perfusion dynamic, vessel structure and oxygenation is crucial in management of arterial hypertension. Constant search for non-invasive methods has led the clinical focus towards the vasculature of the retina, which offers a large opportunity to detect the early phase of the functional and structural changes in the arterial hypertension and can reflect changes in brain vasculature. We review all the available methods of retinal microcirculation measurements including angiography, oximetry, retinal vasculature assessment software, Optical Coherence Tomography Angiography, Adaptive Optics and Scanning Laser Doppler Flowmetry and their application in clinical research. MATERIALS AND METHODS: To further analyse the applicability of described methods in hypertension research we performed a systematic search of the PubMed electronic database (April 2020). In our analysis, we included 111 articles in which at least one of described methods was used for assessment of microcirculation of the retina in hypertensive individuals. RESULTS: Up to this point, the methods most commonly published in studies of retinal microcirculation in arterial hypertension were Scanning Laser Doppler Flowmetry followed shortly by Optical Coherence Tomography Angiography and retinal vasculature assessment software. CONCLUSIONS: While none of described methods enables the simultaneous measurement of all microcirculatory parameters, certain techniques are widely used in arterial hypertension research, while others gain popularity in screening.

Prevalence of Diabetic Retinopathy in Type 1 and Type 2 Diabetes Mellitus Patients in North-East Poland.

Background and Objectives: The global epidemic of diabetes, especially type 2 (DM2), is related to lifestyle changes, obesity, and the process of population aging. Diabetic retinopathy (DR) is the most serious complication of the eye caused by diabetes. The aim of this research was to assess the prevalence of diabetic retinopathy in type 1 and type 2 diabetes mellitus patients in north-east Poland. Materials and Methods: The eye fundus was assessed on the basis of two-field 50 degrees color fundus photographs that showed the optic nerve and macula in the center after the pupil was dilated with 1% tropicamide. Results: The experimental group included 315 (26%) patients with type 1 diabetes mellitus (DM1) and 894 (74%) patients with DM2. DM1 patients were diagnosed with DR in 32.58% of cases, with non-proliferative diabetic retinopathy (NPDR) in 24.44% of cases, proliferative diabetic retinopathy (PDR) in 1.59% of cases, diabetic macular edema (DME) in 5.40% of cases, and PDR with DME in 0.95% of cases. DR was found in DM2 patients in 23.04% of cases, NPDR in 17.11% of cases, PDR in 1.01% of cases, DME in 4.81% of cases, and PDR with DME in 0.11% of cases. Conclusions: The presented study is the first Polish study on the prevalence of diabetic retinopathy presenting a large group of patients, and its results could be extrapolated to the whole country. Diabetic retinopathy was found in 25.48% of patients in the whole experimental group. The above results place Poland within the European average, indicating the quality of diabetic care offered in Poland, based on the number of observed complications.

Pars plana vitrectomy with silicone oil tamponade for primary and secondary macular hole closure: Is it still a useful procedure?

PURPOSE: To evaluate usefulness of posterior vitrectomy with silicone oil tamponade for primary and secondary macular hole closure. METHODS: We searched for publications on the surgical treatment of full-thickness idiopathic and recurrent macular hole. We divided reports into two groups: primary macular hole repair and recurrent macular hole repair with silicone oil tamponade. RESULTS: In primary macular hole treatment, different authors confirmed effectiveness of silicone oil tamponade. They suggest that the most important factor for successful outcome was completeness of vitreous cavity filling with oil. Complications after this method were comparable to those after gas tamponade. However, even if good anatomical results are achieved in secondary macular hole closure, visual acuity is sometimes less rewarding. CONCLUSION: There are reports on good efficacy of silicone oil tamponade for primary and recurrent macular hole closure. Anatomical closure and visual acuity rates in pars plana vitrectomy with silicone oil and with gas filling are comparable. Gas tamponade seems to be safer and needs no more surgery. Postoperative complications in both methods are similar, but all patients with silicone oil filling need to undergo a reoperation to have the silicone removed. There are also other surgical techniques for primary macular hole closure as well as for unsuccessful primary macular hole procedures. We think that primary macular hole closure should be performed with gas tamponade, supported with different adjuvants, as a method of choice. Silicone oil tamponade could be still an alternative in cases, when there are no more efficient techniques or possibilities to treat with success recurrent macular hole.

A review of preoperative manoeuvres for prophylaxis of endophthalmitis in intraocular surgery: topical application of antibiotics, disinfectants, or both?

PURPOSE OF REVIEW: Postoperative endophthalmitis is an ophthalmic surgeon's most feared complication, as it portends a high probability of visual loss. The purpose of this article is to review the literature on the subject of preoperative measures used for prevention of postoperative endophthalmitis and to determine the effectiveness of these measures. RECENT FINDINGS: The present reviewed literature regarding topical prophylaxis of endophthalmitis in cataract surgery. SUMMARY: There is strong evidence for the use of povidone-iodine preoperatively for prophylaxis of postoperative endophthalmitis in ocular surgery; the evidence for topical antibiotics is not as compelling.

Neuronal complications of intravitreal silicone oil: an updated review.

Silicone oil (SiO) has a well-established role as a long-term endotamponade agent in the management of complicated retinal detachments. Complications of intraocular SiO include keratopathy, glaucoma, cataract and subretinal migration of the oil droplets. SiO tamponade can also lead to a severe optic neuropathy caused by retrolaminar migration. Nevertheless, intracranial migration of the SiO through the optic nerve posterior to the lamina cribrosa to the optic chiasm and brain is uncommon. The mechanism is still under debate, but it has been suggested elevated intraocular pressure, macrophages or optic nerve head anatomical predispositions as potential explanations. Moreover, central scotoma may develop in eyes with SiO not only at the time of oil removal, but also during the period of tamponade. We performed a PubMed search of neuronal complications of silicone oil over a period of 25 years. This review summarizes our current understanding of the specific pathogenic mechanisms of intraocular SiO neuronal side effects, concluding that pre-existing glaucoma and optic nerve abnormalities are the main risk factors associated with this damage. In their absence, the risk of extraocular SiO penetration is so low that the use of SiO endotamponade in complex retinal detachment patients does not need to be modified. MRI images to assess extraocular SiO migration are only necessary in very few and special cases, such as patients with optic nerve abnormalities and glaucoma.