Laser Flare Photometry Research Articles

Clinical Features of Behçet’s Disease Uveitis

Abstract: Behçet’s disease (BD) is a chronic, multisystemic vasculitis first described by Professor Hulusi Behçet in 1937. It is characterized by recurrent inflammatory attacks affecting multiple organs, with uveitis being a significant and severe complication that can lead to blindness. BD typically emerges between the ages of 20 and 30 years, with a higher prevalence in males and rare occurrences in children. The prevalence and severity of BD and its ocular symptoms tend to diminish with age. In Turkey, BD is a leading cause of noninfectious uveitis, and its prevalence varies across different regions. Ocular involvement, seen in up to 90% of BD patients, often appears 2–4 years after disease onset and may be the initial sign in 10%–20% of cases. BD uveitis is characterized by recurrent nongranulomatous panuveitis and retinal vasculitis, typically affecting both eyes. Diagnostic tools such as fluorescein angiography (FA), optical coherence tomography (OCT), and laser flare photometry (LFP) are essential for monitoring disease activity and guiding treatment. FA is crucial for identifying occlusive and leaky vasculitis, while OCT helps in detecting macular complications and visualizing retinal infiltrates and their sequelae. LFP quantitatively evaluates intraocular inflammation. Recognizing the ocular manifestations of BD early is vital for accurate diagnosis and effective management. This review highlights the clinical features, diagnostic tools, and importance of early diagnosis in managing BD uveitis.

Monkeypox-related ophthalmic disease (MPXROD): Monitoring the antiviral effect of tecovirimat with monkeypox virus detection in tear samples.

Although monkeypox-related ophthalmic disease (MPXROD) is rare, visual impairing complications have been reported. At present, tecovirimat is the standard-of-care antiviral treatment. In this MPXROD case, the effect of tecovirimat was assessed with PCR analysis of tear samples and concurrent monitoring of inflammation with laser flare photometry (LFP). The patient presented with a palpebral lesion and a corneal ulcer in his right eye, with complete absence of the corneal epithelium, high intraocular pressure and anterior uveitis. MPXV-DNA was detected in tear samples with real-time PCR (RT-PCR). A total volume of 0.5 ml tear-wash was aspirated from the inferior fornix, following instillation of saline onto the ocular surface. In addition, LFP was used to quantify inflammation in both eyes. Viral load in tear samples was detected prior to treatment initiation. In the left eye, tear samples tested negative for MPXV-DNA one week post-treatment while MPXV-DNA was still detected in the right eye, before reaching undetectable levels four weeks post-treatment. Objective quantification of anterior chamber inflammation through LFP demonstrated gradual decrease that was more pronounced in the affected right eye and coincided with the clinical improvement of the corneal ulcer. This case of Mpox related corneal ulcer with associated uveitis manifests the feasibility of monitoring the antiviral effect of tecovirimat with virus detection in tear samples and LFP. Our observations indicate that tecovirimat resulted in viral load reduction in both eyes. RT-PCR MPXV detection in tear samples and LFP represent noninvasive tools that could assist with treatment response monitoring.

Assessment of the degree of inflammatory reaction in uveitis: diagnostic capabilities of clinical methods

Inflammatory diseases of the uvea demonstrate a high incidence and a significant prevalence among people of working age. Uveitis complications often lead to blindness and low vision in patients of various age groups. Diagnostics and monitoring the efficacy of uveitis therapy requires the use of quantitative criteria to assess the degree of inflammatory reaction. The aim of this review is to analyze the informative value and accuracy of various clinical methods for subjective and objective assessment of the inflammatory reaction in the anterior and posterior segments of the eye in uveitis. To assess the inflammatory reaction in uveitis in everyday clinical practice, biomicroscopy is most often used, which is characterized by subjectivity associated with the level of qualification of the ophthalmologist. Other clinical methods, such as fluorescein angiography, optical coherence tomography-angiography, have high sensitivity and informative value along with independence from the subjective impression of the examiner. However, the first of them is invasive, and the second is still not available to a wide range of practicing ophthalmologists today, especially in the “angio” mode. Laser flare photometry is of special importance in the diagnosis of uveitis. It is both a non-invasive and sensitive method that makes it possible to obtain quantitative indicators characterizing the activity of uveal inflammation. The prospects for the application and development of this method are important both for clinical practice and for research purposes.

LASER FLARE PHOTOMETRY IN PRIMARY RHEGMATOGENOUS RETINAL DETACHMENT: An Evaluation of 2,487 Cases.

Exploratory analysis associated with the prospective, multicenter, randomized PRIVENT trial. To characterize the associations between laser flare photometry and anatomical and epidemiological features of rhegmatogenous retinal detachment (RRD). The authors measured laser flare values of all 3,048 prescreened patients excluding those with comorbidities. A mixed regression analysis evaluated the strength of the influencing factors like age, sex, lens status, and presence and extent of RRD on laser flare. Rhegmatogenous retinal detachment was more frequent in men (65.8%) than in women (34.2%, P < 0.001) and in right (52%) than in left eyes (48%, P = 0.045). Phakic RRD affected less quadrants and was less likely to be associated with macula-off status than pseudophakic RRD (48.4% vs. 58.0% macula off, 23% vs. 31% ≥3 quadrants, P < 0.001). Laser flare of affected eyes was significantly higher compared with fellow eyes (12.6 ± 15.2 vs. 8.3 ± 7.4 pc/ms, P < 0.001). The factors age, sex, lens status, presence of RRD, and the number of quadrants affected were independent influencing factors on laser flare. R 2 was 0.145 for phakic and 0.094 for pseudophakic eyes. The results indicate that there may be more factors affecting laser flare than previously assumed. This might limit flare as predictive value for PVR and retinal redetachment.

Efficacy and safety of the implantation of a single-piece angulated foldable IOL in the sulcus.

To study the visual results and tolerance of a Zeiss CT Lucia 601P intraocular lens (IOL) implanted in the sulcus after complicated cataract surgery or during IOL exchange for clouded IOL. In total, 64 patients who underwent sulcus implantation were recalled to the hospital to undergo subjective and objective refraction, best corrected visual acuity measurement, tonometry, optical coherence tomography, laser flare photometry, biometry, and wavefront aberrometry. In spite of a large variation in preoperative refraction, the target refraction was obtained within 1.5 diopters in approximately 97% of patients and within 0.5 diopter in 53% of patients. Average BCVA was high (Snellen 0.86) and related to concomitant (mostly retinal) pathologies in eyes with poorer visual performance. Wavefront aberrometry showed no evidence of IOL tilting or decentration after long-term implantation in the sulcus. Tonometry was not different from the fellow eye of the patient (p > 0.5). In 53 patients with bilateral pseudophakia, the laser flare photometry was not significantly different from the fellow eye (p < 0.05). This study demonstrates that this single-piece angulated foldable acrylic IOL can be considered for implantation in the sulcus. The visual results are favorable, and the IOL can be well-positioned and tolerated in the sulcus. Moreover, there were no safety issues found since there was no evidence of elevated IOP or chronic uveitis.

Laser flare photometry in eyes receiving brolucizumab intravitreal injections for age related macular degeneration.

To measure aqueous flare levels in treatment naïve eyes suffering from wet age- related macular degeneration (wAMD) treated with intravitreal brolucizumab. Patients with treatment naïve wAMD in one eye were prospectively enrolled. Flare levels were measured with laser flare photometry at baseline, 1 day and 1 month after each of the 3 monthly injections during the loading phase. Twenty-two eyes from 22 patients aged 76.7 ± 6.0 years were enrolled. Flare values were 10.6 ± 3.7 photons/msec at baseline and 12.6 ± 5.8 photons/msec at the last follow up visit, 1 month after the third injection (p = 0.289, repeated measures ANOVA). The mean change in flare after the first injection was 4.2 ± 3.6. photons/msec, 6.6 ± 8.9 photons/msec after the 2nd and 8.6 ± 20.8 photons/msec after the 3rd injection (p = 0.640, repeated measures ANOVA). No patient had clinical signs of intraocular inflammation. Eyes receiving brolucizumab injections for wAMD showed similar flare at baseline, during and 1 month after completion of three-monthly intravitreal injections. There was no evidence of subclinical inflammation during the loading phase of brolucizumab based on laser flare photometry measurements.

Screening for juvenile idiopathic arthritis associated uveitis with laser flare photometry in the pediatric rheumatology office: a prospective observational study

BackgroundJuvenile Idiopathic Arthritis (JIA) Associated Uveitis (JIA-U) remains one of the most serious complications of JIA in children. Historically, pediatric JIA is diagnosed by an Optometrist or Ophthalmologist; however, barriers to scheduling increase wait times that may delay diagnosis and treatment. The purpose of this study was to evaluate laser flare photometry (LFP) use to diagnose JIA-U in the Pediatric Rheumatology clinic for patients with JIA.MethodsThis prospective, observational study assessed pediatric patients diagnosed with JIA without a previous history of uveitis between January 2020 and September 2022. All patients underwent at least one evaluation of both eyes using a Kowa FM-600 laser flare photometer during a routine Rheumatology appointment, as well as a standard slit lamp examination (SLE) by optometry or ophthalmology during routine clinical care. Data collected at patient visits included demographics, JIA characteristics, treatment, LFP readings, and anterior chamber (AC) cell grade score utilizing the SUN grading system. Data were summarized using descriptive analyses and the uveitis false positive rate was calculated.ResultsThe study cohort included 58 pediatric patients diagnosed with JIA. The mean age was 8.4 years (1.2–16.3 years) at diagnosis and 11.9 (4.8–16.5 years) at enrollment. The mean duration of disease at time of enrollment was 42 months (range; 0-157 months). Participants were predominantly female (n = 43, 74.1%) and white/Caucasian race (n = 37, 63.8%). The most common JIA subtypes included persistent oligoarticular JIA (n = 19, 32.8%), and RF negative polyarticular JIA (n = 12, 20.7%). There were 12 ANA positive patients (20.7%). At enrollment, 16 patients (27.6%) were not on medications, with 20 (34.5%) on methotrexate, 20 (34.5%) on adalimumab, 6 (10.3%) on tocilizumab, and 5 (8.6%) on etanercept. During the study period, no eye exams detected active uveitis based on SLE with a SUN grade over 0. However, of the 135 LFP readings, 131 (97.0%) were normal, yielding a false positive rate of 3% (95% CI: 0.8%, 7.4%).ConclusionsLFP is a non-invasive tool that can be utilized in the pediatric rheumatology clinic to evaluate for JIA-U. There is a low false positive rate of LFP when compared with standard slit lamp exam.

Comparação do quantitativo de flare do aquoso entre as técnicas de fotometria à laser e avaliação subjetiva em cães submetidos à facoemulsificação

Abstract This study aimed to compare the quantification of aqueous flares using laser photometry and subjective clinical determination after phacoemulsification through the V-prechop nucleodissection technique in dogs. Forty-three dogs of different breeds, males and females, aged 3-10 years, with mature (G2, n = 22) and immature (G1, n = 21) cataracts, were included. After surgery, the patients were evaluated weekly for aqueous flares (using laser flare photometry) and clinically evaluated using slit-lamp biomicroscopy over different periods. Intraocular inflammation was more evident in patients with stage G2 disease than in those with stage G1 disease. Over time, it regressed in most animals, persisting to a mild degree in three animals by the end of the observation period. Statistical analyses revealed key differences between the groups in the immediate postoperative period and after 30 days of observation. “Aqueous flare” (ph/ms), quantified using laser flare photometry, was higher in the operated eyes of both groups (G1 and G2). However, a significant difference was observed in the immediate postoperative period and at 45 and 30 days in groups G1 and G2, respectively. Furthermore, when comparing the operated eyes of each group, a significant difference was observed in the preoperative period and 60 days postoperatively; the mean values were always higher in the G2 patients (G1-preop = 25.5 ± 11.4 ph/ms and G2-preop = 45.7 ± 17.7 ph/ms; G1-60d = 23.4 ± 8.9 ph/ms and G2-60d = 39.8 ± 13.4 ph/ms). In conclusion, laser cell and flare photometry showed higher accuracy in evaluating aqueous flares than clinical evaluation based on scores during the postoperative period in phacoemulsification by V-prechop nucleodissection. The quantitative values of flares obtained using this non-invasive method may also be used to evaluate other nucleodissection techniques in phacoemulsification.

Efficacy and Safety of PreserFlo MicroShunt Implantation and Its Effects on Intraocular Inflammation through Laser Flare Photometry.

The primary objective of this study is to evaluate the efficacy and safety profile of PreserFlo MicroShunt implantation in the medium- to long-term follow-up of patients with open-angle glaucoma. The secondary objective is to analyze laser flare meter (LFM) values before and after PreserFlo MicroShunt implantation. This prospective, observational, longitudinal single-center study included a total of 62 eyes from 54 patients. A subgroup of 27 eyes (26 patients) reached the 12-month follow-up. Success was defined based on three criteria: criterion A: IOP ≤21 mmHg and ≥20% reduction; criterion B: IOP ≤15 mmHg and ≥25% reduction; and criterion C: IOP ≤12 mmHg and ≥30% reduction. Success was further categorized as complete if achieved without IOP-lowering medications and qualified if achieved with medication administration. Other aspects evaluated included the number of IOP-lowering medications (baseline and postoperative), development of postoperative complications, 5-FU injections or implant revision, and LFM values. The 12-month follow-up group (27 patients) was composed by 50% males and had a mean age of 75.54 ± 9.98 years. Success rates at 12 months were as follows: 78% for criterion A, 56% for criterion B, and 26% for criterion C. Complete success, as defined by criterion A, was achieved by 67% of the patients, 29% achieved qualified success, and one eye (4%) experienced failure. IOP decreased from 25.26 ± 1.67 mmHg at baseline to 14.81 ± 0.74 mmHg at 12 months. The number of medications decreased from 3.67 ± 1.30 at baseline to 0.48 ± 0.75 at 12 months. Reported complications were choroidal detachment (11%), hyphema (5%), and athalamia (flat anterior chamber) (2%) 13 eyes (48%) received 5-FU injections, while 7 eyes (26%) underwent implant revision. No significant increase in LFM values was observed. Eyes with a regular postoperative course and IOP ≤15 mmHg showed significantly lower LFM values than patients with unfavorable outcomes (IOP >15 mmHg, development of complications, 5-FU injection, or implant revision). PreserFlo MicroShunt showed a significant reduction in IOP and a decrease in the number of IOP-lowering medications. Complications occurred at a modest frequency. The implant provides a minimally invasive approach with no significant increases in LFM values postoperatively. Higher LFM values correlate with unfavorable postoperative outcomes.

Evaluation of Central and Peripheral Retinal Vascular Changes in the Fellow Eyes of Patients with Unilateral Retinal Vein Occlusions

To evaluate the subtle peripheral retinal and macular vascular changes in the fellow eyes of patients with unilateral retinal vein occlusion (RVO). This retrospective study included 53 patients with unilateral RVO and 44 age-matched controls. The frequency of peripheral retinal vascular pathologies in both eyes was evaluated using high quality ultra-wide field fluorescein angiography (UWFFA). Macular vascular density, flow area, and foveal avascular zone measurements from optical coherence tomography angiography (OCTA) were analyzed together with laser flare photometry values in patients and controls. Peripheral retinal vascular pathologies were detected on UWFFA in the fellow eyes of 36 (67.9%) patients. No significant central vascular pathologies were detected on OCTA and there was no significant difference in OCTA parameters between the fellow eyes and the controls. Flare values did not differ significantly between the control and the fellow eyes. Two thirds of the fellow eyes of unilateral RVO patients had subtle peripheral retinal vascular changes, while there was no significant microvascular change detected with OCTA in the macula. This suggests that vascular changes caused by systemic vascular disorders probably first start in the peripheral retina of the fellow eyes of patients with RVO.

Evaluation of the structural changes of uveitis patients by optical biometry.

Objective (Aim): To observe the ocular structural changes in active and inactive uveitis patients. Methods: This retrospective study involved 30 patients (32 eyes) with anterior and intermediate uveitis cases and 54 eyes of 54 cases in a control group, who were admitted to the Ophthalmology Department at Trakya University. In the study group, 14 patients were females, 16 patients were males and in the control group 26 volunteers were females, and 28 volunteers were male of the 54 volunteers. Anterior chamber depth, axial length, intraocular pressure, lens thickness, central corneal thickness, steep and flat values in keratometry, corrected visual acuity in both eyes, anterior chamber cells, and vitreous cells were measured and compared between three groups (two uveitis groups - active and inactive - and control group). Results: In the comparison of the median values of axial length, central corneal thickness, and steep and flat values of keratometry, the values of the patients with active uveitis were higher than the ones in the control group in each parameter, but no significant difference was observed. The anterior chamber depth parameter value was higher, the lens thickness value was lower in patients with active uveitis than the values in the control group and the differences were statistically significant (p<0,05). No significant structural differences in the values of the active and inactive group patients (p>0,05) were observed. Conclusions: Only lens thickness and anterior chamber depth parameters were statistically significant in patients with active uveitis, compared with the inactive uveitis group. Anterior chamber depth measurement values were higher and lens thickness measurement values were lower in patients with active uveitis when compared with the control group. Abbreviations: AAU = Acute anterior uveitis, CAU = Chronic Anterior Uveitis, AC = Anterior Chamber, IOP = Intraocular Pressure, IVCM = in vivo Confocal Microscopy, AS-OCT = Anterior Segment Optical Coherence Tomography, UBM = Ultrasound Biomicroscopy, LFP = Laser Flare Photometry, KP = Keratic Precipitates, OCT = Optical Coherence Tomography, AL = Axial Length, ACD = Anterior Chamber Depth, LT = Lens Thickness, CCT = Central Corneal Thickness, Ks = Steep Value of Keratometry, Kf = Flat Value of Keratometry, AUP = Active Uveitis Patients, IUP = Inactive Uveitis Patients, SUN = Standardization of Uveitis Nomenclature.

Laser Flare Photometry to Monitor Childhood Chronic Uveitis: A Preliminary Report of a Monocentric Italian Experience.

Background: Childhood chronic non-infectious uveitis (cNIU) is a challenging disease that needs close monitoring. Slit lamp evaluation (SLE) is the cornerstone of ophthalmological evaluation for uveitis, but it is affected by interobserver variability and may be problematic in children. Laser flare photometry (LFP), a novel and objective technique, might be used in children with uveitis. Aim: The aim of this study was to attempt the use of LFP in cNIU clinical practice. Methods: Children, attending the Rheumatology Unit and who were scheduled to receive ophthalmological evaluation, were prospectively enrolled to concomitantly receive SLE and LFP. SLE was performed blind to LFP measure. Demographic, laboratory, clinical, and ophthalmology data were collected. Results: A total of 29 children (58 eyes) were enrolled, including 3 with juvenile idiopathic arthritis without uveitis (JIA-no-U), 15 with JIA-associated uveitis (JIA-U), and 11 with idiopathic chronic uveitis (ICU). We observed significantly higher LFP values in the eyes of children with uveitis compared to the others (10.1 IQR 7.1-13.6 versus 6.2 IQR 5.8-6.9, p = 0.007). Accordance between the SLE and LFP measures, at baseline (ρ.498, p < 0.001) and during the follow-up (LFP II ρ 0.460, p < 0.001, LFP III ρ 0.631, p < 0.001, LFP IV ρ 0.547, p = 0.006, LFP V ρ 0.767, p = 0.001), was detected. We evaluated significant correlation between LFP values and the presence of complications (ρ 0.538, p < 0.001), especially with cataract formation (ρ 0.542, p < 0.001). Conclusions: In this cohort, LFP measurements showed a good correlation with SLE. LFP values showed a positive correlation with the presence of complications. LFP might be considered as a reliable objective modality to monitor intraocular inflammation in cNIU.

Intravitreal Injection of Bevacizumab for the Prevention of Postoperative Proliferative Vitreoretinopathy in High-Risk Patients Selected by Laser Flare Photometry

Introduction: To evaluate the effect of an intravitreal injection of bevacizumab at the time of rhegmatogenous retinal detachment (RRD) surgery, on postoperative proliferative vitreoretinopathy (PVR) in high-risk patients selected by laser flare photometry. Methods: This single-center observational retrospective cohort study included 137 consecutive patients who underwent pars plana vitrectomy and gas tamponade for primary RRD with increased aqueous flare between July 2016 and June 2021. From June 2019, an intravitreal injection of bevacizumab was administered as an adjunct to RRD repair. Patients who underwent surgery before this time and who did not receive intravitreal bevacizumab served as controls. The main outcome was the rate of retinal redetachment due to PVR. Results: The median flare value was 22.0 (16.5–36.5) pc/ms in the control group and 28.2 (19.7–41.0) pc/ms in the bevacizumab group (p = 0.063). Eyes treated with bevacizumab were more likely to have macula-off RRD (p = 0.003), grade B PVR (p = 0.038), and worse visual acuity (p = 0.004) than controls. The rate of PVR redetachment was significantly lower in the bevacizumab group (11.1%) than in the control (30.1%) (p = 0.012). This difference was more pronounced after adjusting for potential confounding factors (p = 0.005); the risk of developing PVR was 4.5-fold higher in controls (95% CI, 1.6–12.8). After adjustment, the final median visual acuity was also significantly higher in eyes treated with bevacizumab (p = 0.025). Conclusion: This pilot study provides preliminary evidence that bevacizumab may reduce the risk of PVR-related recurrent RRD and improve visual outcomes in high-risk patients selected by laser flare photometry.

Assessing quantitatively the state of the blood-aqueous barrier by laser flare photometry: a review

This review discusses the experience in applying laser flare photometry, a non-invasive technique, in ophthalmology, to assess quantitatively the state of the blood-aqueous barrier (BAB) in patients with certain ocular and systemic disorders. The method allows reliable detection of such biomarkers of the state of the BAB as the intensity of the scattered light (flare) and number of cells in the aqueous of the anterior chamber, sometimes even at the subclinical level, which significantly improves the capability for early diagnosis and objective treatment monitoring.

The effect of one- and two–rectus muscle strabismus surgery on anterior chamber flare

To investigate the effect of the most commonly performed strabismus surgery procedures on the blood-aqueous barrier using laser flare photometry (LFP). Patients who underwent unilateral or bilateral strabismus surgery between January 2020 and May 2021 were included. Eyes were grouped according to the number of rectus muscles operated: one rectus muscle procedure (recession) with or without inferior oblique anterization (IOA), ipsilateral two rectus muscle procedure (recession and resection) with or without IOA, and unoperated fellow eyes of patients undergoing unilateral surgery. Anterior chamber flare values were measured by LFP for each eye the day before the surgery and day 1, week 1, and month 1 postoperatively. A total of 66 eyes of 33 patients (21 females) were included. There were 29 eyes in the one-muscle group, 22 in the two-muscle group, and 15 in the fellow-eye group. The mean flare values of the two-muscle group were significantly higher than those of the other groups at postoperative day 1 and week 1 (P = 0.001, for both). The mean postoperative day 1, week 1, and month 1 flare values of the two-muscle group were significantly higher than the mean preoperative flare value. There were no significant differences between pre- and postoperative flare values of the one-muscle or fellow-eye groups (P > 0.05, for both). In our study cohort, LFP provided evidence of subclinical changes in the blood-aqueous barrier up to the first month postoperatively in otherwise healthy patients undergoing two-muscle surgery compared with those undergoing one-muscle surgery and unoperated fellow eyes.

Die Blut-Augen-Schranken und ihre Störungen: Anatomie, Physiologie, Pathologie

Complex barriers comprise the blood-aqueous (BAB) and the blood-retinal barrier (BRB), and separate anterior and posterior eye chambers, vitreous body, and sensory retina from the circulation. They prevent pathogens and toxins from entering the eye, control movement of fluid, proteins, and metabolites, and contribute to the maintenance of the ocular immune status. Morphological correlates of blood-ocular barriers are tight junctions between neighboring endothelial and epithelial cells, which function as gatekeepers of the paracellular transport of molecules, thereby limiting their uncontrolled access to ocular chambers and tissues. The BAB is composed of tight junctions between endothelial cells of the iris vasculature, endothelial cells of Schlemm's canal inner wall, and cells of the nonpigmented ciliary epithelium. The BRB consists of tight junctions between endothelial cells of the retinal vessels (inner BRB) and epithelial cells of the retinal pigment epithelium (outer BRB). These junctional complexes respond rapidly to pathophysiological changes, thus enabling vascular leakage of blood-derived molecules and inflammatory cells into ocular tissues and chambers. Blood-ocular barrier function, which can be clinically measured by laser flare photometry or fluorophotometry, is compromised in traumatic, inflammatory, or infectious processes, but also frequently contributes to the pathophysiology of chronic diseases of the anterior eye segment and the retina, as exemplified by diabetic retinopathy and age-related macular degeneration.

Orbital Lesion as the Initial Manifestation of a Neuroendocrine Tumour

Laser flare photometry provides a non-invasive and objective measurement of the Tyndall effect in the anterior chamber. The laser flare value (measured in photon number per millisecond [pc/ms]) thus quantifies the extent of disruption to the blood-aqueous barrier and can be used in clinical applications to monitor uveitis therapy or to measure the postoperative degree of inflammation. Standardised performance must be observed during measurement. Publications of the last 35years on laser flare photometry deal not only with the measurement procedure but also with its use in clinical practice for different ophthalmological pathologies. Likewise, various influencing factors have already been investigated and described that must be considered when measuring and evaluating laser flare values. The focus of this article is the relevance of laser flare photometry in retinal pathologies. In recently published studies, the level of objective tyndallometry in primary rhegmatogenous retinal detachment is shown to depend on lens status, symptom duration, and extent of retinal detachment. The greater is the area of the retina affected, the greater the disruption of the blood-aqueous barrier appears to be. Elevated laser flare values have also been considered as a predictor for the development of proliferative vitreoretinopathy (PVR). However, based on current knowledge, this assumption must be put into perspective. According to current data, objective tyndallometry can be used to monitor the progression of intraocular inflammation and to quantify the blood-aqueous barrier, and the values correlate with the extent and anatomical features, as well as the symptom duration in retinal detachment. Many influencing factors have already been identified. But further evaluation is desirable and needed. It is still unclear whether laser flare values can be used in the future as a predictor for sequelae such as PVR development.

Changes in Macular Thickness after Cataract Surgery in Patients with Open Angle Glaucoma.

The purpose of this study was to examine the changes in IOP, total macular and RNFL, ganglion cell layer (GCL) thickness, and aqueous humour flare in open angle glaucoma (OAG) patients before and 6 months after cataract surgery. This was a prospective observational case-control age- and gender-matched study. Groups: 40 subjects in a controlled OAG (OAGc) group, 20 subjects in an uncontrolled OAG (OAGu) group, and 60 control group subjects. complete ophthalmic evaluation, IOP measurement, anterior and posterior segment Optical Coherence Tomography (OCT), and laser flare photometry before and 6 months postoperatively. Six months postoperatively IOP decreased in all groups. An increase in macular thickness was found postoperatively in all groups. Preoperative aqueous humour flare was higher in the OAGc group than in the control group. After cataract surgery, aqueous humour flare was higher in the control group compared to the preoperative result. Changes in IOP following cataract surgery were strongly negatively correlated with preoperative IOP. An increase in macular thickness was observed 6 months postoperatively in all groups. Aqueous humour flare did not differ in OAGc and OAGu groups pre- and postoperatively but significantly increased in the control group postoperatively.

Factors influencing aqueous flare after cataract surgery and its evaluation with laser flare photometry.

Despite the refinement of modern cataract surgery, postoperative inflammation still constitutes a substantial amount of visual morbidity worldwide. A surrogate for intraocular inflammation and blood-aqueous barrier breakdown can be objectively quantified by Laser flare photometry (LFP). This review outlines the utility of LFP in assessing the assessment of post-cataract surgery inflammation. It highlights the impact of preoperative pathological states such as uveitis and diabetes, intraoperative techniques, including efficient phacoemulsification and direct comparisons between postoperative anti-inflammatory regimes. There is a large interobserver variation in the subjective flare measurement after cataract surgery and the continued use of LFP amongst other objective, noninvasive measurements of intraocular inflammation, particularly in the further development of cataract surgery, is recommended.

The Value of Laser Flare Photometry as a Monitoring Tool for Uveitis.

Laser flare (LF) photometry (P) is used to quantify the protein concentration in the aqueous humor, and therefore assess the blood-aqueous humor barrier. LFP is more reliable than the clinical assessment of the Tyndall effect, and is thus especially useful in the follow-up of uveitis patients. In active uveitis, LFP correlates well with the anterior chamber cell grading. Various studies have shown that high LF values are associated with an increased risk of uveitic complications, such as macular edema, glaucoma, and posterior synechiae. LFP can also be used to assess the response to anti-inflammatory treatments as well as the optimal timing and selection of the surgical technique for intraocular surgeries.