Aperture photometry measurements of melanin particles in Krukenberg spindles of the cornea in pigment dispersion syndrome

Technology and Health Care ◽

10.3233/thc-202501 ◽

2021 ◽

pp. 1-8

Author(s):

Maciej Czepita

Keyword(s):

Open Source Software ◽

Signal To Noise Ratio ◽

Pigment Epithelium ◽

Video Recording ◽

Pigment Dispersion ◽

Pigmentary Glaucoma ◽

Image Brightness ◽

Pigment Dispersion Syndrome ◽

Video Images ◽

The Right

BACKGROUND: Quantification of melanin pigment release in pigment dispersion syndrome as well as observations of melanin brightness changes can be valuable information in the management of this rare ocular disease. OBJECTIVES: Previous studies have focused on examining the iris pigment epithelium and aqueous humor. Therefore, the aim of this study was to examine the cornea. METHODS: A novel technique was developed for this purpose based on aperture photometry. Slit lamp digital video images of the cornea were recorded. A single frame from each video recording based on the quality was chosen for further processing and analysis. Aperture photometry was performed with AstroImageJ open source software. Aperture selection was performed automatically. Melanin particles displaying a signal-to-noise ratio above 20 were analyzed. RESULTS: A total of 16 melanin particles from the right eye of the patient participating in the study were detected and a further 9 melanin particles from the left eye. The examined area of the cornea measured 348 × 348 pixels in the image. Brightness differed by as much as 8.98 × among particles in the right eye and 2.03 × in the left eye. CONCLUSIONS: It seems feasible for this new method to be potentially used in the monitoring of patients with pigment dispersion syndrome and pigmentary glaucoma as well as in other ocular diseases.

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Use of automatic refractometer infrared images to screen pigment dispersion syndrome: a cross-sectional observational study from a preliminary hypothesis

Medical Hypothesis, Discovery & Innovation in Optometry ◽

10.51329/mehdioptometry104 ◽

2020 ◽

Vol 1 (1) ◽

pp. 25-28

Author(s):

Paolo Brusini ◽

Veronica Papa

Keyword(s):

Observational Study ◽

Pigment Epithelium ◽

Anterior Segment ◽

Pigment Dispersion ◽

Pigmentary Glaucoma ◽

Infrared Images ◽

Cross Sectional ◽

Pigment Dispersion Syndrome ◽

Automatic Refractometer ◽

Iris Pigment Epithelium

Background: This study was performed to evaluate the use of anterior segment images, obtained with an automatic refractometer, to identify early defects of the iris pigment epithelium in patients with pigment dispersion syndrome (PDS) or pigmentary glaucoma (PG) without observable alterations at the slit lamp. Methods: In this cross-sectional observational study, carried out from January 2018 to December 2019, in Policlinico Citta di Udine Health Center, Udine, Italy, we observed anterior segment infrared images of 1700 subjects who were undergoing routine ophthalmological examination using an automatic refractometer. We selected infrared images of subjects who fulfilled the inclusion and exclusion criteria and looked for a focal defect in the iris pigment epithelium. Results: Twenty patients with focal iris pigment epithelial defect were identified and none of them showed evident signs of PDS. After the necessary explanations, they agreed to have further examinations to verify the possibility of PDS. An in-depth evaluation of ocular structures, including gonioscopy, demonstrated the presence of PDS in all subjects with iris defects. Conclusions: The use of infrared images obtained by an automatic refractometer could provide early and easy identification of PDS in crowded ophthalmology clinics or mass screening programs; yet, more well-designed studies are necessary to confirm these preliminary findings and prove this proposed screening tool.

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Pigment Dispersion Syndrome and Pigmentary Glaucoma in an Emmetropic Young Male

Nepalese Journal of Ophthalmology ◽

10.3126/nepjoph.v12i1.23972 ◽

2020 ◽

Vol 12 (1) ◽

pp. 139-145

Author(s):

Neha Verma ◽

Qamar Jawaid

Keyword(s):

Pigment Epithelium ◽

Anterior Segment ◽

Young Male ◽

Retinal Nerve Fibre Layer ◽

Pigment Dispersion ◽

Pigmentary Glaucoma ◽

Visual Field Examination ◽

Pigment Dispersion Syndrome ◽

Normal Limits ◽

Hereditary Nature

Introduction: Pigment dispersion Syndrome (PDS) is a disorder with an onset in mid–twenties. There occurs a disruption of the iris pigment epithelium and deposition of pigment granules throughout the anterior segment. The incidence of PDS is 4-8/ 100,000. This condition is more commonly seen In Caucasians and is considered to be rare in Indians. Case: A 33-year-old male presented with the complaint of headache for three months. He had normal vision in both eyes with visual acuity of 6/6. Observation: Krukenberg’s spindle, a classic sign of pigment dispersion syndrome was evident on slit-lamp examination over the posterior corneal surface. Gonioscopy revealed a heavy and uniformly pigmented trabecular meshwork. OCT (Optical Coherence Tomography) demonstrated a characteristic iris configuration in the form of a mid-peripheral posterior bowing of the iris .Retinal nerve fibre layer analysis done on OCT revealed glaucomatous thinning in the right eye and a more advanced defect in the left eye. A visual field examination revealed the field to be outside normal limits in both the eyes pointing towards a diagnosis of pigment dispersion glaucoma. Conclusion: The purpose of presenting this case is to caution the clinicians to carefully examine young emmetropes who present with Krukenberg’s spindle as it could be associated with PDS. Patients with Krukenberg’s spindle and without elevated lOP are often treated as normal. These patients must be cautioned regarding possible future consequences of the disease and counseled regarding the hereditary nature of the syndrome.

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The Role of Dynamic Ultrasound Biomicroscopy in defining Laser Treatment in Pigment Dispersion Syndrome/ Pigmentary Glaucoma. A Case Series

International Archives of BioMedical and Clinical Research ◽

10.21276/iabcr.2016.2.3.16 ◽

2016 ◽

Vol 2 (3) ◽

Author(s):

Atif Anwar ◽

◽

Triputi Nath

Keyword(s):

Laser Treatment ◽

Case Series ◽

Ultrasound Biomicroscopy ◽

Pigment Dispersion ◽

Pigmentary Glaucoma ◽

Pigment Dispersion Syndrome ◽

Dynamic Ultrasound

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Exome-based investigation of the genetic basis of human pigmentary glaucoma

BMC Genomics ◽

10.1186/s12864-021-07782-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Carly van der Heide ◽

Wes Goar ◽

Kacie J. Meyer ◽

Wallace L. M. Alward ◽

Erin A. Boese ◽

...

Keyword(s):

Genetic Basis ◽

Immunohistochemical Analysis ◽

Pigment Dispersion ◽

Pigmentary Glaucoma ◽

Visual Disability ◽

Primary Analysis ◽

Human Donor ◽

Similar Frequency ◽

Pigment Dispersion Syndrome ◽

Rare Mutations

Abstract Background Glaucoma is a leading cause of visual disability and blindness. Release of iris pigment within the eye, pigment dispersion syndrome (PDS), can lead to one type of glaucoma known as pigmentary glaucoma. PDS has a genetic component, however, the genes involved with this condition are largely unknown. We sought to discover genes that cause PDS by testing cohorts of patients and controls for mutations using a tiered analysis of exome data. Results Our primary analysis evaluated melanosome-related genes that cause dispersion of iris pigment in mice (TYRP1, GPNMB, LYST, DCT, and MITF). We identified rare mutations, but they were not statistically enriched in PDS patients. Our secondary analyses examined PMEL (previously linked with PDS), MRAP, and 19 other genes. Four MRAP mutations were identified in PDS cases but not in controls (p = 0.016). Immunohistochemical analysis of human donor eyes revealed abundant MRAP protein in the iris, the source of pigment in PDS. However, analysis of MRAP in additional cohorts (415 cases and 1645 controls) did not support an association with PDS. We also did not confirm a link between PMEL and PDS in our cohorts due to lack of reported mutations and similar frequency of the variants in PDS patients as in control subjects. Conclusions We did not detect a statistical enrichment of mutations in melanosome-related genes in human PDS patients and we found conflicting data about the likely pathogenicity of MRAP mutations. PDS may have a complex genetic basis that is not easily unraveled with exome analyses.

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Clinical Characteristics of Pigment Dispersion Syndrome and Pigmentary Glaucoma Patients: A Cross-sectional Study

JOURNAL FOR CLINICAL AND DIAGNOSTIC RESEARCH ◽

10.7860/jcdr/2020/46939.14383 ◽

2020 ◽

Author(s):

Vijay Pratap Singh Tomar ◽

Sandeep Sharma ◽

Rahul Bhardwaj ◽

Sindhuja Singh ◽

Virendra Kumar Pal ◽

...

Keyword(s):

Visual Field ◽

Optic Disc ◽

Clinical Characteristics ◽

Cross Sectional Study ◽

Pigment Dispersion ◽

Pigmentary Glaucoma ◽

Spherical Equivalent ◽

Sectional Study ◽

Cross Sectional ◽

Pigment Dispersion Syndrome

Introduction: Pigmentary Glaucoma (PG) and Pigment Dispersion Syndrome (PDS) are two different spectrums of a single disease. Since the disease is seen in younger population and is rapidly progressive blinding disease, therefore early diagnosis and treatment will reduce the burden of the disease and improve the quality of life. Aim: To evaluate clinical characteristics of PDS and PG patients in eastern part of Uttar Pradesh. Materials and Methods: This was a two years (1st January 2018 to 31st December 2019) hospital‑based retrospective cross‑sectional study of patients who attended the glaucoma clinic. Diagnosis of PDS was made when they had normal optic disc, normal visual field {with or without increased Intra Ocular Pressure (IOP)} and at least two of the following three signs were found clinically: Krukenberg spindle, homogenous moderate‑to‑heavy (≥Spaeth 2+) Trabecular Meshwork (TM) pigmentation, and any degree of zonular and/or lenticular pigment granule dusting. Patients with PDS were diagnosed with PG, if they had two or more of the following findings: initial IOP >21 mmHg, glaucomatous optic nerve damage or glaucomatous visual field loss. Various parameters such as influence of demographics, IOP, Best‑Corrected Visual Acuity (BCVA), Central Corneal Thickness (CCT), Mean Deviation (MD), Visual Field Index (VFI %), spherical equivalent and clinical finding of anterior segment of study patients were analysed. Mean, standard deviation and percentage were calculated using GraphPad Instat version 3.0. Results: Among 40 patients, nine eyes of the six patients had myopia of ‑0.5D or greater, with mean refractive error of ‑3.55±4.72 spherical equivalent. The average baseline IOP in study patients (PDS+PG), was 30.21±11.42 mmHg. Twenty four (60%) patients, either in one or both eyes had glaucoma, secondary to PDS at the initial diagnosis. Thirty three (82.5%) patients had Krukenberg spindles. Homogeneous TM pigmentation was seen in all patients. Typical spoke‑like radial Iris Transillumination Defects (ITDs) were not observed in any of the patients except in one patient, who had isolated short slit‑like trans‑illumination defects in iris crypts. Conclusion: PDS patients with normal optic disc and visual field and raised IOP, should be started prophylactic treatment and needs to be monitored more closely. Thus, the finding of PDS in Indians should alert the ophthalmologist to look for glaucoma during the initial examination.

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