Aqueous humor analysis after Nd:YAG laser capsulotomy with the laser flare-cell meter

Prevalence and clinical characteristics of uveitic glaucoma: multicentric study in Bogotá, Colombia

OBJECTIVES

To describe the clinical features of patients diagnosed with uveitic glaucoma (UG) and ocular hypertension secondary to uveitis (OHT-SU).

METHODS

A multicentric cross-sectional study using medical records of patients with uveitis between 2013 and 2021. Uveitis and glaucoma specialists examined all patients. Variables were analyzed using the chi-square or Fisher's exact test for categorical variables. Additionally, t test, Mann-Whitney, and Kruskal-Wallis variance analysis were used for continuous variables. Finally, a Kaplan-Meier survival analysis for UG and OHT-SU development over time was done.

RESULTS

Of the 660 clinical records reviewed of patients with uveitis, 191 (28.9%) had OHT-SU in at least one visit, and 108 (16.4%) of them developed UG. In all ages, females were more affected than males. Anterior uveitis was the main anatomic localisation, and non-granulomatous, recurrent, and inactive uveitis were the most frequent clinical features. The mean final visual acuity was 0.3 (0.0-1.0) LogMAR. Also, 95.8% of the patients had additional sequelae related to uveitis regardless of UG and OHT-SU. Interestingly, males had earlier affection, with statistical significance in OHT for adults (P = 0.036) and UG for children (P = 0.04). Of all patients, 81.1% received topical hypotensive treatment and 29.8% required a surgical procedure.

CONCLUSIONS

UG and OHT-SU are common complications of uveitis in the Colombian population. These sight-threatening conditions were more common and appeared sooner in men at any age. Our results suggest that earlier and more aggressive treatment with topical hypotensive agents could positively influence the visual outcomes and the requirement of surgical procedures.

Quantification of Postoperative Inflammation in Laser and Surgical Procedures for Glaucoma with Laser Flare Photometry: A Review of the Literature

PURPOSE

To review the application of laser flare photometry (LFP) in the objective quantification of aqueous flare (anterior chamber inflammation) post laser and surgical procedures for glaucoma.

METHODS

A search was undertaken using the following: PubMed (all years), the Web of Science (all years), Ovid MEDLINE (R) (1980 to 30 March 2023), Ovid MEDLINE (R) Daily Update 30 March 2023, MEDLINE and MEDLINE non-indexed items, Embase (1980-2021, week 52), Ovid MEDLINE (R) and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1980 to 30 March 2023), CENTRAL (including Cochrane Eyes and Vision Trials Register), metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (www.who.int/ictrp/search/en). Search terms included "aqueous flare," "anterior chamber inflammation," "tyndallometry," "laser flare photometry" combined with "laser," "iridotomy," "trabeculoplasty," "cataract surgery," "phacoemulsification," "glaucoma surgery," "minimally invasive glaucoma surgery," "trabeculectomy," "aqueous shunt," "glaucoma drainage" and "cyclophotocoagulation."

RESULTS

The majority of studies utilizing laser flare photometry in grading flare have been post laser trabeculoplasty. The degree of flare produced varies according to the type of glaucoma laser or surgery performed, with filtration procedures and glaucoma drainage devices having marked and prolonged detectable levels. Aqueous flare in cyclodestructive procedures positively correlated with intraocular pressure (IOP) reduction.

CONCLUSION

In comparison to clinician grading, laser flare photometry provides a more objective measure of post-surgical inflammation in eyes that have undergone laser and surgery for glaucoma. Further research is warranted into how this instrument can be utilized to identify eyes at high risk of failure and other adverse outcomes after glaucoma surgery.

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.

Quantification of Inflammation Following Nd:YAG Laser Capsulotomy and Assessing the Anti-inflammatory Effects of Nepafenac 0.1% and Betamethasone 0.1

Purpose: To quantify the intraocular inflammation, measured using laser flare photometry (LFP), after Nd:YAG capsulotomy and compare the effects of different topical anti-inflammatory regimes.Methods: A single-center, prospective, randomized controlled study, which included 90 eyes of 90 patients with visually significant posterior capsular opacification. In all patients, Nd:YAG capsulotomy was done and was then randomized into three groups: (A) Topical betamethasone 0.1%; (B) Topical nepafenac 0.1%; and (C) Control group: did not receive any anti-inflammatory agent post capsulotomy.Results: There was a significant increase in the mean LFP values 2 h following laser capsulotomy (p < 0.001) and then declined gradually and came back to pre-laser values by 2 weeks in all three groups. The mean LFP values, central macular thickness, and best corrected visual acuity were comparable among groups. None developed central macular edema.Conclusion: Intraocular inflammation following Nd:YAG capsulotomies is minimal and transient. Routine use of prophylactic anti-inflammatory agents may be avoided.

Application of Laser Flare Photometry in the Quantification of Blood-Aqueous Barrier Breakdown after Micro-incision Vitrectomy

Purpose: The purpose of the study is to quantify aqueous flare using laser flare photometry (LFM) in patients undergoing 25-G pars plana vitrectomy (PPV) and assess the need for postoperative topical corticosteroid administration . Methods: Prospective evaluation of 50 eyes (50 patients) was performed using LFM until day 30 postoperative. Duration of surgery, indication of PPV, and use of laser and/or cryotherapy were noted. Topical corticosteroids were used if mean LFM values were >50, or if there was anterior chamber fibrin. Results: Mean age of the subjects was 48.62 ± 10.07 years. The preoperative LFM value for 50 subjects was 17.42 ± 25.20. Topical corticosteroids were initiated in only 22 patients. The LFM values of subjects were not different from baseline at 1 month whether or not the subjects received corticosteroids (p > 0.106). Conclusions: With 25-G PPV, there is minimal breakdown of blood-aqueous barrier. LFM helps in monitoring postoperative inflammation, obviating the need for topical corticosteroids in significant number of patients.

Pathogenesis of Uveitic Glaucoma

Uveitic glaucoma consists one of the most serious complications of intraocular inflammation and, despite its rarity, is considered as one of the leading causes of preventable loss of vision worldwide. It has been associated with a wide spectrum of inflammatory diseases, but its pathogenesis is still not fully comprehended. It appears that the type of inflammation, the steroid-response and the anatomical alterations of the anterior chamber play a pivotal role. To our knowledge, the mechanisms may be both acute and chronic. The main targets of the treatment are to control the inflammation and reduce the intraocular pressure (IOP). The management of glaucoma associated with uveitis remains an extremely challenging condition for ophthalmologists. The successful treatment of uveitic glaucoma is inextricably correlated with prompt and immediate therapeutic decisions. Very often a solid collaboration between clinicians from different specialties may be required for treating the underlying disease.

Further understanding of its pathogenesis can indicate therapeutic targets and may lead to the development of new and more efficient therapeutic approaches. New glaucoma surgical modalities may ameliorate the prognosis after surgical intervention, but this calls for further evaluation. This study aims to highlight the complexity of uveitic glaucoma analyzing the main pathogenetic mechanisms and the correlations with the inflammatory response.

Laser flare-cell photometer: principle and significance in clinical and basic ophthalmology

A slit-lamp examination is an indispensable and essential clinical evaluation method in ophthalmology, but, it is qualitative subjective. To complement its weaknesses in making a quantitative evaluation of flare intensity and number of cells in the aqueous humor in the eye, we invented the laser flare-cell photometer in 1988. The instrument enables a non-invasive quantitative evaluation of flare intensity and number of cells in the aqueous with good accuracy and repeatability as well as maneuverability equal to slit-lamp microscopy. The instrument can elucidate the pathophysiology in the blood-aqueous barrier (BAB) function in a variety of ocular disorders. The accuracy of the instrument makes it possible to investigate not only the pathophysiology of intraocular disorders but also the effects of various drugs and surgical procedures in BAB. The instrument does not only lighten the burden on patients in clinical examinations and study but it also helps minimize the sacrifice of experimental animals and improves the reliability of the results by minimizing inter-individual variations through its good repeatability. Here I shall relate how the instrument has been applied to clinical and basic studies in ophthalmology and what novel knowledge its application contributed to pathophysiology in ophthalmology.

The Pathogenesis of Raised Intraocular Pressure in Uveitis

AIM

To analyze current understanding of the factors that contribute to raised intraocular pressure (IOP) in patients with uveitis.

METHODS

A pubmed literature review was carried out using words including "uveitic glaucoma", "IOP AND uveitis", "ocular hypertension AND uveitis", "inflammation AND glaucoma", "aqueous dynamics" AND "glaucoma/uveitis".

RESULTS

Of the two studies looking at the aqueous dynamics in experimentally induced uveitis, both found aqueous flow decreased acutely, and one found that uveoscleral outflow increased. This is likely to reflect the types of uveitis that present acutely with hypotony. A study examining patients with Fuch's heterochromic cyclitis found no difference in aqueous flow or uveoscleral outflow. No studies have examined aqueous dynamics in types of uveitis that present with acutely raised IOP. Levels of prostaglandins rise in acute uveitis, which has been shown to increase uveoscleral and trabecular outflow, without affecting aqueous flow. Studies have demonstrated that raised levels of trabecular protein reduce trabecular outflow. Steroid treatment, inflammatory cells, free radicals and enzymes are also likely to contribute to the development of raised pressure. When considering the impact of the pathogenesis of raised pressure in uveitis on its treatment, prostaglandins may provide good intraocular pressure control, but there are concerns regarding their theoretical ability to worsen the inflammatory response in uveitis. Studies have not conclusively proven this to be the case. Surgical success rates vary, but trabeculectomy plus an antimetabolite, deep sclerectomy plus an antimetabolite, and Ahmed valve surgery have been used.

CONCLUSIONS

Uveitic glaucoma is caused by a number of different diseases, some of which present with acute hypotony, others with acutely raised IOP, and others which demonstrate an increase in IOP over time. Further studies should be carried out to examine the differing pathogenesis in these types of diseases, and to establish the best treatment options.

Comparative Analysis of Anterior Chamber Flare Grading between Clinicians with Different Levels of Experience and Semi-automated Laser Flare Photometry

PURPOSE

To assess correlation for anterior chamber flare grading between clinicians with different levels of experience and with semi-automated flare reading in a cohort of patients with heterogeneous uveitic entities.

METHODS

Fifty-nine observations from 36 patients were recorded and analyzed for statistical association. In each patient, flare was assessed objectively using the Kowa FM-700 laser flare photometer, and subjective masked grading by two clinicians was performed.

RESULTS

The study demonstrated disparity in flare readings between clinical graders with one step disagreement in clinical grading in 26 (44.06%) eyes (p < 0.001) and concordance between the flare readings by experienced grader and flare photometry. After review of semi-automated flare readings, management was changed in 11% of the patients.

CONCLUSION

Laser flare photometry can be a valuable tool to remove the observer bias in grading flare for selected cohort of uveitis patients. It can be further applied to titrate therapy in intraocular inflammation.

The Effect of ND:YAG Laser Posterior Capsulotomy Size on Refraction, Intraocular Pressure, and Macular Thickness

Purpose. The aim of this study is to examine the influence of capsulotomy size on, spherical equivalent (SE), intraocular pressure (IOP), and macular thickness. Materials and Methods. Sixty-eight patients were examined preoperatively and 1, 4, and 12 weeks after Nd:YAG capsulotomy. Patients were divided into two groups based on the postoperative capsulotomy size. Changes in SE, IOP, and macular thickness were compared between two groups. Results. We found a higher hyperopic shift in large capsulotomy group. In both groups 1 and 2, IOP increased 1 week postoperatively. Intraocular pressure rise in group 2 was higher than in group 1. Both groups had increased macular thickness at 1 week postoperatively. The degree of macular thickening was similar in group 1 and group 2. Comment. Patients who underwent a larger capsulotomy have a higher hyperopic shift and IOP elevation. Rise in macular thickness was similar in large and small capsulotomy groups.

Time course of changes in aqueous flare intensity after vitrectomy for rhegmatogenous retinal detachment

PURPOSE

To investigate the time course of changes in aqueous flare intensity after vitrectomy for rhegmatogenous retinal detachment (RD) and to determine the clinical factors related to an increase in aqueous flare.

METHODS

The present study included 22 unilateral patients with RD undergoing primary 20-gauge vitrectomy. Aqueous flare intensity was measured preoperatively and at 1 week, 2 weeks, 1 month, and 3, 6, and 12 months postoperatively using the laser flare meter.

RESULTS

Before vitrectomy, aqueous flare intensity was significantly higher in eyes with RD than in contralateral normal eyes. Vitrectomy increased aqueous flare intensity, and the peak was observed at the first postoperative week. Aqueous flare intensity decreased to a stable level at 3 months postoperatively but remained significantly higher than that of contralateral and preoperative eyes throughout the observation period. Clinical factors that were found to be significantly correlated with an increase in aqueous flare intensity included 1) before the surgical procedure: extent of RD and intraocular pressure, and 2) 3 months postoperatively: size of retinal breaks, number of laser photocoagulation spots, operation time, and performance of combined cataract surgery. Multiple regression analysis revealed that aqueous flare intensity at 3 months postoperatively had significant correlation with the size of retinal breaks (P < 0.005) and the number of laser photocoagulation spots (P < 0.05).

CONCLUSION

Aqueous flare intensity after vitrectomy for RD decreased to a stable level at 3 months postoperatively but remained significantly higher than the normal level. The size of retinal breaks and the degree of surgical invasion were associated with the increase in aqueous flare.

Neodymium:yttrium-aluminum-garnet capsulotomy and intraocular pressure in pseudophakic patients with glaucoma

OBJECTIVE

To determine the 1- and 3-hour changes in intraocular pressure after neodymium:yttrium-aluminum-garnet (Nd:YAG) capsulotomy in pseudophakic patients with glaucoma and to determine the effect of acetazolamide and apraclonidine on these changes.

DESIGN

Randomized controlled trial.

PARTICIPANTS

Pseudophakic patients with glaucoma requiring Nd:YAG posterior capsulotomy (n = 76).

INTERVENTION

Patients undergoing Nd:YAG posterior capsulotomy were randomly allocated to receive no therapy, oral acetazolamide (250 mg), or topical apraclonidine 1% within 1 hour before capsulotomy.

MAIN OUTCOME MEASURES

Intraocular pressures 1 and 3 hours after laser therapy were recorded.

RESULTS

Data were available for 76 eyes in 76 patients. Twenty-nine patients received no therapy; 24, oral acetazolamide; and 23, apraclonidine. One fifth (6/29) of patients with glaucoma developed a pressure rise of > or =5 mmHg if untreated, and 3% (1/29) developed a pressure rise of >10 mmHg. In comparison, no patients in the acetazolamide group developed a pressure rise of > or =5 mmHg (P = 0.02), and 1 of 24 in the apraclonidine group (P = 0.08) developed such a pressure rise, with none developing a pressure rise of >10 mmHg. When comparing all treated with nontreated, a reduction in the proportion with pressure rise was found (P = 0.01). All of the patients who developed a pressure rise of > or =5 mmHg did so within the first hour.

CONCLUSIONS

In the absence of therapy, clinically significant post-Nd:YAG pressure rises occur in one fifth of patients with glaucoma undergoing capsulotomy. Oral acetazolamide and topical apraclonidine reduce the frequency and magnitude of pressure rises and are of comparable effectiveness. In this study, all clinically important pressure rises developed within the first hour.

Use of Nd:YAG laser capsulotomy

Surgery for cataract removal has become successively refined such that posterior capsular opacification is the most common problem presenting after modern cataract extraction. Various techniques and treatments exist to manage patients with posterior capsular opacification using Nd:YAG capsulotomy. There are many possible variations in initial assessment, pre-laser treatments, laser techniques, and follow-up routines. The literature on the use of Nd:YAG laser for capsulotomy was reviewed and interpreted. This article presents the currently available knowledge in a format that allows the practitioner to tailor an evidence-based protocol for treating patients with symptomatic posterior capsule opacification.

Posterior capsule opacification and lens epithelial cell layer formation: Hydroview hydrogel versus AcrySof acrylic intraocular lenses

PURPOSE

To quantitatively compare the incidence of visually significant posterior capsule opacification (PCO) and lens epithelial cell (LEC) layer formation on the anterior surface of Hydroview hydrogel and AcrySof acrylic foldable intraocular lenses (IOLs) after implantation.

SETTING

Single-surgeon ophthalmology practice, Orange Base Hospital, and Dudley Private Hospital, Orange, New South Wales, Australia.

METHODS

This retrospective study comprised 166 eyes of 150 patients (after exclusions) who had cataract extraction and insertion of a foldable IOL in the capsular bag by a single surgeon using a standardized phacoemulsification technique from December 1997 to September 1998. The mean follow-up was 13.1 months (range 6.0 to 23.6 months). The eyes were divided into 2 groups based on the type of IOL implanted: Storz Hydroview H60M (81 eyes) or Alcon AcrySof MA30BA (85 eyes). A neodymium:YAG posterior capsule laser capsulotomy (PC YAG) was performed for an objective decrease in Snellen best corrected visual acuity (BCVA) of more than 1 line, significant visual symptoms, or both. This was used as a measure of visually significant PCO. An Nd:YAG anterior surface clearance (ASC YAG) was done for LEC layer formation anterior to the IOL to better visualize or facilitate treatment of PCO. The rates of PC YAG and ASC YAG after Hydroview and AcrySof IOL implantation were statistically compared.

RESULTS

Forty-five eyes (55.6%) in the Hydroview IOL group and 3 eyes (3.5%) in the AcrySof IOL group required a PC YAG; the risk difference was 52.0% (P <.001). An ASC YAG was required in 27 eyes (33.3%) in the Hydroview group and 1 eye (1.2%) in the AcrySof group; the risk difference was 32.2% (P <.001). Survival analysis demonstrated that the only independent predictor of the incidence of PC YAG and ASC YAG over time was IOL type, with the Hydroview IOL group having a statistically significantly higher incidence of both procedures.

CONCLUSION

There was a greater incidence of visually significant PCO and LEC layer formation on the anterior surface of Hydroview IOLs than of AcrySof IOLs.

Randomized clinical trial of a new dexamethasone delivery system (Surodex) for treatment of post-cataract surgery inflammation

OBJECTIVE

To evaluate the safety of Surodex Drug Delivery System (Oculex Pharmaceuticals, Inc., Sunnyvale, CA) containing dexamethasone 60 micrograms, for use in cataract surgery, and to compare its anti-inflammatory efficacy with conventional dexamethasone 0.1% eyedrops.

DESIGN

Randomized, masked, and partially controlled trial.

PARTICIPANTS

Sixty eyes of 60 Asian patients undergoing extracapsular cataract extraction with intraocular lens implantation were examined. Of these, 28 eyes of 28 patients served as control eyes. Patients were stratified for age and presence of diabetes mellitus.

INTERVENTION

Surodex was inserted in the anterior chamber of 32 eyes at the conclusion of surgery. These eyes received placebo eyedrops four times a day after surgery for 4 weeks. Control eyes received neither Surodex nor a placebo implant but were prescribed conventional 0.1% dexamethasone eyedrops four times a day for 4 weeks.

MAIN OUTCOME MEASURES

Anterior chamber cells and flare were clinically graded at the slit lamp. Anterior chamber flare was objectively assessed with the Kowa FM500 Laser Flare Meter (Kowa Co. Ltd, Tokyo, Japan) for up to 3 months after surgery. Intraocular pressure and corneal endothelial specular microscopy with morphometric cell analysis were performed for up to 1 year after surgery.

RESULTS

Clinical slit-lamp assessment of anterior chamber flare and cells showed no difference between Surodex-treated eyes and dexamethasone eyedrop-treated eyes. Flare meter readings showed lower flare levels in the Surodex group at all postoperative visits compared with the dexamethasone eyedrop group. Flare reduction in the Surodex group reached statistical significance at days 4, 8, 15, and 30 after surgery. At 3 months, flare was reduced to preoperative levels in the Surodex group but was still raised in the dexamethasone eyedrop group. Five eyes in the dexamethasone eyedrop group required augmentation of steroids and were deemed therapeutic failures as opposed to one eye in the Surodex group. One patient in the dexamethasone eyedrop group developed postoperative open-angle glaucoma with profound visual field loss and optic disc cupping, resulting in hand movements vision. No significant difference in endothelial cell loss was noted between Surodex-inserted eyes and dexamethasone eyedrop-treated eyes for up to 1 year after surgery.

CONCLUSIONS

Intraocular placement of a single Surodex is a safe and effective treatment method to reduce intraocular inflammation after cataract surgery. There was no statistical difference in efficacy between Surodex and 0.1% dexamethasone eyedrops in reducing intraocular inflammation, as measured by clinical methods, while Surodex was clearly superior to eyedrops in reducing aqueous flare as objectively assessed with the laser flare meter.

Posterior continuous curvilinear capsulorhexis and postoperative inflammation

PURPOSE

To evaluate the influence of posterior continuous curvilinear capsulorhexis (PCCC) on inflammation after phacoemulsification and implantation of a foldable silicone intraocular lens (IOL) in the capsular bag.

SETTING

St. Erik's Eye Hospital, Stockholm, Sweden.

METHODS

Fifty patients were enrolled in this prospective, randomized study. Eyes with diabetes mellitus, glaucoma, uveitis, exfoliation syndrome, other previous ocular diseases, or an axial length greater than 26.0 mm were excluded. One group comprised 25 eyes of 25 patients (median age 76 years) in which phacoemulsification and implantation of a silicone IOL in the capsular bag were performed. The other group consisted of 25 eyes of 25 patients (median age 77 years) who received the same surgical procedure in addition to PCCC. The aqueous protein concentration was measured using a laser flare meter (FC 500, Kowa Co.) preoperatively and 1 day, 1 week, and 1 and 3 months after surgery.

RESULTS

Surgical trauma significantly increased aqueous flare values 1 day, 1 week, and 1 month after surgery in both groups (P < .05). Three months postoperatively, flare values in both groups were not different from preoperative values. No difference between the 2 groups was found in flare intensity measurements or in best corrected visual acuity before and after uneventful surgery. The incidence of postoperative clinical cystoid macular edema was 8% (2 eyes) in the control group and 4% (1 eye) in the group with PCCC.

CONCLUSION

Postoperative flare intensity after phacoemulsification with PCCC and implantation of a foldable silicone IOL was not significantly different than postoperative flare measurements in a control group.

A systematic overview of the incidence of posterior capsule opacification

OBJECTIVE

Reported rates of posterior capsule opacification (PCO) vary widely and are based on various definitions of PCO, varying lengths and intervals of follow-up, and the use of different surgical techniques, intraocular lens (i.o.l.) designs, and methods of IOL implantation. This study was designed to obtain a more precise overall estimate of the incidence of PCO and to explore factors that might influence the rate of PCO development.

DESIGN

A meta-analysis.

METHODS

Published articles were selected for study based on a computerized MEDLINE search of the literature and a manual search of the bibliographies of relevant articles. Articles meeting selected inclusion criteria were reviewed systematically, and the reported data were abstracted and synthesized using the statistical techniques of meta-analysis.

MAIN OUTCOME MEASURE

Pooled estimates of the proportion of eyes developing PCO at three postoperative timepoints--1 year, 3 years, and 5 years--were measured.

RESULTS

There is significant heterogeneity among published rates of PCO. The overall pooled estimates (95% confidence limits) of the incidence of PCO were 11.8% (9.3%-14.3%) at 1 year, 20.7% (16.6%-24.9%) at 3 years, and 28.4% (18.4%-38.4%) at 5 years after surgery. There is no evidence of a significant decline in PCO incidence during the study period.

CONCLUSIONS

Visually significant PCO develops in more than 25% of patients undergoing standard extracapsular cataract extraction or phacoemulsification with posterior chamber intraocular lens implantation over the first 5 years after surgery. Patient characteristics, surgical techniques, and differences in research design and reporting may account for some of the variability in reported rates. However, no specific factors were identified in the authors' analysis. More precise estimates of incidence and identification of risk factors for PCO will depend on the development of a standardized measurement of PCO and wider adoption of more rigorous study methodology.

Flare-cell meter measurement of inflammation after uneventful cataract surgery with intraocular lens implantation

PURPOSE

To determine whether intracapsular intraocular lens (IOL) implantation leads to less anterior chamber inflammation than sulcus implantation in eyes having uneventful extracapsular cataract extraction (ECCE).

SETTING

Division of Ophthalmology, University of Alicante, Spain.

METHODS

This study comprised 314 consecutive uneventful ECCEs with implantation of a rigid poly(methyl methacrylate) IOL performed by the same surgeon. Inflammation was assessed by evaluating aqueous flare and cells using a laser flare-cell meter. Flare and cells were measured in both eyes of all patients preoperatively and on postoperative days 1, 2, 3, 4, 5, 7, 10, and 15 and at the end of months 1, 2, and 3. In 131 eyes (41.7%), the haptics were in the bag and in 114 (36.3%), in the sulcus. In 69 eyes (22.0%), implantation was combined sulcus-bag.

RESULTS

Flare and cell counts were high on day 1 regardless of the haptic placement. The counts were highest in eyes with sulcus implantation (32.4 +/- 3.6 [SD] flare; 31.8 +/- 3.2 cells) and lowest in eyes with in-the-bag implantation (27.5 +/- 4.7 flare; 22.3 +/- 2.8 cells). One day postoperatively, the difference between groups in cell count was statistically significant but not in flare measurements. There were no significant between-group differences on day 2 and thereafter. Thirty days postoperatively, flare and cell counts were similar in all eyes.

CONCLUSION

Inflammation after uneventful ECCE with IOL implantation resolved within about 3 months of surgery, with flare and cell counts similar to those preoperatively. There was a small but detectable difference in flare and cell counts on the first day after surgery based on haptic location.

Intraocular pressure elevation after simple pars plana vitrectomy

PURPOSE

The purpose of the study is to determine the incidence, timing, and severity of variability in the intraocular pressures (IOPs) from baseline after simple pars plana vitrectomy.

METHODS

A prospective study was performed in 25 consecutive patients undergoing simple pars plana vitrectomy. Intraocular pressures were measured before surgery, immediately after surgery, and then at 2, 4, 6, 12, and 24 hours after surgery.

RESULTS

The mean IOP was elevated significantly 2 hours after surgery when compared with the mean immediate postoperative IOP (30.3 mmHg +/- 11.0 mmHg vs. 17.4 mmHg +/- 7.0 mmHg, P < 0.001). A steady decline was seen at all succeeding timepoints. The 24-hour mean (17.3 mmHg +/- 4.3 mmHg, P = 0.923) was similar to baseline. Ninety-two percent of eyes had a 2-hour postoperative IOP that was higher than the IOP at the completion of surgery. Forty percent of patients required medical management for IOP greater than or equal to 30 mmHg.

CONCLUSIONS

Significant IOP elevation can occur after simple pars plana vitrectomy. The optimal time for detecting the pressure rise during the first 24 hours is 2 hours after surgery.

Glaucoma associated with uveitis

Raised intraocular pressure is a common and frequently serious complication of anterior uveitis. The milieu of inflammatory cells, the mediators they release, and the corticosteroid therapy used to treat the uveitis can participate in the pathogenesis of uveitic glaucoma. These factors alter the normal anatomic structure of the anterior chamber and angle, influencing aqueous production and outflow. These changes act to disrupt the homeostatic mechanisms of intraocular pressure control. Structural changes in the angle can be acute, such as in secondary angle closure with pupillary block glaucoma, or chronic, such as combined steroid-induced and secondary open angle glaucoma. Management of uveitic glaucoma may be difficult because of the numerous mechanisms involved in its pathogenesis. Diagnostic and therapeutic decisions are guided by careful delineation of the pathophysiology of each individual case. The goal of treatment is to minimize permanent structural alteration of aqueous outflow and to prevent damage to the optic nerve head. This article reviews the pathogenesis of uveitic glaucoma, with specific attention to etiology. Medical and surgical therapies are also discussed, with emphasis on the more recent developments in each category.

Effect of intraocular lens fixation on acute intraocular pressure rise after neodymium-YAG laser capsulotomy

Neodymium-YAG laser posterior capsulotomy is associated in some cases with an acute rise in the intraocular pressure (IOP), possibly caused by blockage of the trabecular meshwork by debris. To test the hypothesis that the IOP rise is preventable if fixation of the intraocular lens (IOL) in the capsular bag is ensured, we conducted a study comparing IOP changes at 1, 2, 3 and 24 hours after Nd:YAG capsulotomy between eyes with capsular bag-fixated, one haptic in the bag (haptic in/out) and cillary sulcus-fixated IOLs. Analysis of variance for repeated measures showed that after capsulotomy there were significant increases in IOP from baseline (p < 0.05) in both the sulcus-fixated (1, 2 and 3 hours) and haptic in/out groups (2 and 3 hours), while IOPs in the bag-fixated group did not show any significant increase. The increases in IOP in the sulcus-fixated group at 1, 2 and 3 hours after capsulotomy were significantly higher than the IOP changes at the corresponding periods in the other two groups (Kruskal-Wallis test, p < 0.01). The mean maximum IOP rise in the sulcus-fixated group (11.33 +/- 7.85 mmHg) was significantly higher than that in the haptic in/out group (3.89 +/- 7.14 mmHg) and the bag-fixated group (1.10 +/- 2.71 mmHg), while there was no difference between the latter two groups. In 57.5% of the sulcus-fixated group, 5% of the haptic in/out group and none of the eyes of the bag-fixated group the IOP rise was more than 10 mmHg. A significantly larger proportion of sulcus-fixated eyes had anterior chamber cells and capsular debris after capsulotomy (chi 2 test, p < 0.001). In the haptic in/out group significant correlation (-0.56, p = 0.009) between IOP rise at 1 hour and the percentage enclosure of the IOL by the anterior capsule was demonstrated. There was no significant difference in maximum IOP rise between glaucomatous and non-glaucomatous eyes (Mann-Whitney U-test, p = 0.49).

Study of the blood-aqueous barrier in choroidal melanoma

AIMS

Aqueous flare was used to determine the frequency and amount of blood-aqueous barrier breakdown and correlate it with tumour variables.

METHODS

Aqueous flare was analysed prospectively by laser flare photometry in 139 consecutive patients seen in the oncology unit for choroidal melanoma. Both eyes of patients were examined with a laser flare cell meter in a standard fashion.

RESULTS

Mean flare difference between healthy and tumour eyes was 3.01 (SD 2.5) photons per millisecond (ph/ms) in 32 cases of small melanomas (p < 0.0001), 10.74 (13.9) ph/ms in 92 cases of medium and large melanomas (p < 0.0001), and 19.23 (11.8) ph/ms in 15 cases of very large melanomas (p < 0.0001). This mean differential flare was significantly higher in medium and large than in small melanomas (p < 0.002) and in very large melanomas than in medium and large melanomas (p < 0.028). A difference of > or = 7 ph/ms between affected and healthy eyes was noted in 70 of 139 melanomas (50.4%). It was found in 3/32 small melanomas (9.4%), in 53/92 medium and large melanomas (57.6%), and in 14/15 very large melanomas (93.3%).

CONCLUSION

Multiple linear regression analysis showed that flare was most strongly correlated with tumour volume (r = 0.43; p < 0.0001) and tumour height (r = 0.41; p < 0.0008).

Sensitivity of laser flare photometry to monitor inflammation in uveitis of the posterior segment

PURPOSE

Laser flare photometry is a new quantitative method for evaluating aqueous flare, making flare the only inflammatory parameter that can be evaluated precisely and objectively. The validity of the method already has been demonstrated in anterior segment inflammation. The aim of this study is to assess the validity and limitations of the method to quantify and monitor inflammation in uveitis with predominant involvement of the posterior segment.

METHODS

Five well-defined conditions with uveitis predominant in the posterior segment were analyzed in this study: Behçet uveitis, pars planitis, posterior sarcoidosis, posterior pole toxoplasmosis, and birdshot chorioretinopathy. (1) Mean initial (pretreatment) flare was determined; (2) in the patients needing systemic steroid therapy, introduction of therapy was correlated with evoluting laser flare photometry; and (3) in patients with quiescent disease, the predictive value of a defined subclinical photometry-detected flare rise for disease recrudescence was analyzed.

RESULTS

Initial pretreatment flare was 331.8 +/- 47.7 photon counts per millisecond (ph/msecond) (mean +/- standard error of the mean) for Behçet uveitis, 15.6 +/- 1.3 ph/msecond for pars planitis, 26.9 +/- 4.6 ph/msecond for posterior sarcoidosis, 7.5 +/- 1.0 ph/msecond for posterior pole toxoplasmosis, 5.8 +/- 0.7 ph/msecond for birdshot chorioretinopathy, and 4.7 +/- 0.1 ph/msecond for a group of 88 control eyes. A significant flare reduction after start of steroid therapy was seen in Behçet uveitis (78% reduction), sarcoidosis (44.8%), and pars planitis (51%), but not in toxoplasmosis or in birdshot. A small flare rise had a predictive value for disease recrudescence in 27/35 patients (predictive value, 0.77; sensitivity rate, 100%). The level of associated blood-aqueous barrier disruption for reliable follow-up of posterior uveitis was empirically determined to be 13 to 15 ph/msecond.

CONCLUSION

Laser flare photometry was found to be very sensitive to monitor inflammation in uveitis of the posterior segment as long as a sufficient level of associated blood-aqueous barrier disruption (flare) was present.

Lasers in ophthalmology

This article reviews the principle uses of ophthalmic lasers, providing historical background with an emphasis on new applications and areas of investigation. Ophthalmic photocoagulation was the first medical laser application and has restored or maintained vision in millions of people. More recently, photodisruption and, increasingly, ablation have gained prominence for treating a wide range of ocular pathology. The unique properties of lasers have also been harnessed for diagnostic purposes, with optical coherence tomography representing a significant improvement over existing imaging methods. Many ophthalmic applications of lasers have been developed, but the field is a dynamic one which continues to evolve along with laser technology itself.

Evaluation of laser flare-cell photometry in the appraisal and management of intraocular inflammation in uveitis

BACKGROUND

Laser flare-cell photometry enables objective and quantitative measurement of anterior chamber inflammation. Systematic data currently are used mainly for clinical research; few are yet available in uveitis. The authors prospectively studied the amount, duration, and pattern of inflammation for well-defined uveitic conditions and evaluated the potential usefulness of laser flare-cell photometry in uveitis.

METHODS

Mean initial flare was calculated in HLA-B27-positive acute anterior uveitis, acute herpes zoster uveitis, acute retinal necrosis (ARN), Fuchs heterochromic cyclitis, intermediate uveitis (pars planitis-type), posterior sarcoidosis, posterior pole toxoplasmosis, and birdshot chorioretinopathy. Evolution of aqueous flare and cells was analyzed for acute anterior uveitis, ARN, and pars planitis treated for cystoid macular edema (CME), all of which received a standardized therapy.

RESULTS

Blood-aqueous barrier disruption was very pronounced in acute anterior uveitis (170.2 +/- 33 photons/msecond), ARN (177.4 +/- 88 photons/msecond), moderate in posterior sarcoidosis (38.1 +/- 11 photons/msecond), acute zoster uveitis (25.8 +/- 6.1 photons/msecond), and pars planitis (19.1 +/- 2.9 photons/msecond) but only minimal in Fuchs heterochromic cyclitis (10.2 +/- 3.5 photons/msecond), toxoplasmosis (9.0 +/- 1.2 photons/msecond) and birdshot chorioretinopathy (5.7 +/- 1.1 photons/msecond). For acute anterior uveitis, ARN, and pars planitis with CME, the inflammatory patterns were determined. The potential of laser flare-cell photometry for precise follow-up and adjustment of therapy was illustrated in cases of anterior and posterior uveitis.

CONCLUSION

The authors' findings show that laser flare-cell photometry allows quantitative assessment of inflammation in uveitis and contributes to improved management of patients with uveitis.

Uveoscleritis after excessive neodymium:YAG laser posterior capsulotomy

A 66-year-old woman developed severe and recurrent scleritis and uveitis after neodymium:YAG capsulotomy performed 18 months after cataract extraction. Four cracks on the intraocular lens and plastic splinters in the vitreous indicated that excessive laser energy had been used. Inflammation was treated successfully only when a combination of dexamethasone acetate 0.1% drops (Maxidex), drops of diclofenac sodium 0.1% (Voltaren Ophtha), and systemic diclofenac sodium (Voltaren) was used. Inflammation might be explained by chronic irritation of the ciliary body by a displaced haptic or by an immune reaction triggered by damage to the ciliary body at the time of excessive posterior capsulotomy.