Nd:YAG laser iridotomy in pigment dispersion syndrome: an ultrasound biomicroscopic study

Primary observations of EVO ICL implantation for high myopia with concave iris

PURPOSE

To investigate the morphological changes of concave iris in myopic patients after EVO implantable collamer lens (ICL) implantation.

METHODS

EVO ICL candidates with posterior bowing iris were observed using ultrasound biometric microscopy (UBM) in this prospective nonrandomized observational study. Forty patients were enrolled, with 20 patients in the concave iris group and the other 20 patients in the control group. None of the patients underwent laser peripheral iridotomy. All patients received preoperative and postoperative examinations, which included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), subjective manifest refraction and intraocular pressure. UBM was used to observe iris curvature (IC), irido-corneal angle (ICA), posterior chamber angle (PCA), iris-lens contact distance (ILCD), iris-zonule distance (IZD) and ciliary process length (CPL). Anterior chamber angle pigment was observed by gonioscopy. The preoperative and postoperative data were analyzed using SPSS.

RESULTS

The average follow-up period was 13.3 ± 5.3 months. The mean efficacy indices were 1.10 ± 0.13 and 1.07 ± 0.11 (P = 0.58), and the safety indices were 1.19 ± 0.09 and 1.18 ± 0.17 in the control group and the concave iris group (P = 0.93), respectively. The IOP postoperatively were 14.13 ± 2.02 mmHg and 14.69 ± 1.59 mmHg in control and concave iris groups (P = 0.37). Preoperatively, the concave iris group was presented with greater IC (P < 0.0001), longer ILCD (P < 0.0001), wider ICA (P = 0.004), narrower PCA (P = 0.01), and shorter IZD (P = 0.03) than the control group. In the concave iris group, IC, ILCD and ICA were significantly decreased after ICL implantation (P < 0.0001), while PCA and IZD were significantly increased (P = 0.03 and P = 0.04, respectively). Postoperative IC, ILCD, ICA, PCA and IZD were not statistically different between groups (P > 0.05). There was no significant difference in pigment deposition grades between the two groups (P = 0.37).

CONCLUSION

After EVO ICL implantation, the morphology of concave iris was significantly improved, which may reduce the risk of intraocular pigment dissemination caused by iris concavity. The concave iris has no impact on the safety of EVO ICL surgery during the follow-up.

Pigment dispersion syndrome and pigmentary glaucoma: overview and racial disparities

Pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) are two stages within the same ophthalmic disease spectrum, which are known to be affected by race. The prevalence of PDS is underestimated, largely due to its minor clinical symptoms. Although the prevalence of PG is low, the visual impairment associated with PG is extremely severe. The prevalence of PDS-PG is four or more times higher in Caucasians than in Blacks or Asians, and the "classic" PDS in Caucasians has long been used as a benchmark diagnostic criterion. Following extensive research focused on African Americans and Asians, the standard for diagnosing PDS-PG was refined. At the same time, the pathogenesis of PDS is not the same in different races. Hence, the effectiveness of preventive treatment and the need for treatment may not be equivalent in different races. The rate of conversion of PDS to PG is nearly 1/3 in Caucasians and higher in blacks and Asians, requiring more aggressive treatment and monitoring. We systematically searched a PubMed database from inception to March 2022 to provide an overview of research progress in various aspects of PDS-PG. Specifically, this paper considers the effects of race on disease prevalence, clinical manifestation, diagnostic criteria, disease mechanism, hereditary traits, treatment, and prevention to provide an accurate and comprehensive guide for the diagnosis and treatment of PDS-PG in various races.

Validation of the vault prediction model based on the sulcus-to-sulcus diameter and lens thickness: a 925-eye prospective study

BACKGROUND

To verify the accuracy and stability of the prediction formula based on the ciliary sulcus diameter and lens thickness and to analyse factors influencing the prediction results.

METHODS

In total, 925 eyes from 506 subjects were enrolled in this prospective study between July 1, 2020, and June 30, 2021. Subjects were divided into four seasons, each spanning three months. The target vault was set to be between 300 μm and 700 μm according the prediction formula. The actual vault was measured one month postoperatively. The Bland-Altman test, 95% confidence intervals (95% CI) and 95% limits of agreement (95% LoA) were used to evaluate the agreement between the predicted vault and the actual vault. Eyes with absolute prediction errors greater than 300 μm were further analysed.

RESULTS

The mean predicted vaults for the four seasons were 503 ± 99, 494 ± 96, 481 ± 92 and 502 ± 93 μm, while the mean actual vaults were 531 ± 189, 491 ± 179, 464 ± 179 and 529 ± 162 μm, respectively. The predicted and actual vaults of the overall subjects were 493 ± 95 and 500 ± 180 μm, respectively. Of the 925 eyes, 861 eyes (93.08%), 42 eyes (4.54%), and 22 eyes (2.38%) showed a normal vault, high vault, and low vault, respectively. Bland-Altman plots showed that the mean difference between the actual vault and predicted vault overall (± 95% LoA) was 6.43 ± 176.2 μm (-339 to 352 μm). Three UBM features may lead to large prediction errors (more than 300 μm): wide iris-ciliary angle (ICA), iris concavity and anteriorly positioned ciliary body.

CONCLUSIONS

This study demonstrated the accuracy and stability of the prediction formula through the validation of a large sample size and a long time span. Wide ICA, iris concavity and anteriorly positioned ciliary body may have an effect on vault.

Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility

Acute primary angle closure glaucoma is a potentially blinding ophthalmic emergency requiring prompt treatment to lower the elevated intraocular pressure in humans and dogs. The PACG in most of canine breeds is epidemiologically similar to humans with older and female patients overrepresented with the condition. The American Cocker Spaniel (ACS) is among the most common breeds observed with PACG development in dogs. This study initially sought to identify genetic risk factors to explain the high prevalence of PACG in ACSs by using a case-control breed-matched genome-wide association study. However, the GWAS failed to identify candidate loci associated with PACG in this breed. This study then assessed intrinsic ocular morphologic traits that may relate to PACG susceptibility in this breed. Normal ACSs without glaucoma have a crowded anterior ocular segment and narrow iridocorneal angle and ciliary cleft, which is consistent with anatomical risk factors identified in humans. The ACSs showed unique features consisting of posterior bowing of iris and longer iridolenticular contact, which mirrors reverse pupillary block and pigment dispersion syndrome in humans. The ACS could hold potential to serve as an animal model of naturally occurring PACG in humans.

[Pigmentary glaucoma: yesterday, today, tomorrow]

Pigment dispersion syndrome (PDS) is a condition that mostly affects young men with myopic refraction. PDS is characterized by the presence of Krukenberg spindle, peripheral iris defects, significant trabecular meshwork pigmentation, as well as convex iris configuration. Such configuration can cause friction of iris's posterior pigment layer on its ligaments, which leads to the release of pigment and its accumulation mostly in the structures of the anterior chamber. Over time PDS can progress into pigmentary glaucoma (PG), which in turn can lead to permanent loss of vision. This review analyzes available data on diagnosis and treatment of PDS and PG.

Pigment dispersion syndrome and its implications for glaucoma

Pigment dispersion syndrome (PDS) represents a clinical spectrum of a relatively common and usually underdiagnosed phenomenon produced by spontaneous pigment dispersion from the iris into the anterior segment. PDS is often bilateral, has no gender predisposition, and presents at a young age, particularly in myopes. Although most patients experiencing an episode of pigment dispersion are asymptomatic, extreme photophobia, ocular pain, redness, and blurred vision may occur. Other characteristic signs are iridolenticular contact, concave iris configuration, 360° peripheral iris transillumination, and pigment deposition on the anterior chamber angle or the corneal endothelium (Krukenberg spindle). Early PDS diagnosis is crucial to detect patients with pigment-related ocular hypertension (POHT) that can eventually lead to pigmentary glaucoma (PG). The latter represents a sight-threatening condition in which mechanical, environmental, and genetic factors contribute to optic nerve damage. In this review, we update the pathogenic mechanisms involved in the clinical spectrum of the disease. We describe its clinical presentation, ophthalmologic manifestations, and complications, including the factors influencing the development of POHT and PG. Because PDS has variable clinical presentations that lead to misdiagnoses, we emphasize the differential diagnosis and the actual therapeutic strategies according to disease status.

Effects of Nd-YAG Laser iridotomy on anterior segment measurements in pigment dispersion syndrome and ocular hypertension

PURPOSE

To compare the anterior segment optical coherence tomography (AS-OCT) measurements of eyes with pigment dispersion syndrome (PDS) and ocular hypertension (OHT) before and after neodymium:yttrium-aluminum-garnet (Nd:YAG) laser peripheral iridotomy (LPI).

METHODS

A total of 23 eyes of 23 patients with PDS and OHT with features of PDS were included in this retrospective study. All of the eyes with PDS and OHT were examined by AS-OCT before and after Nd:YAG LPI. Anterior chamber depth, angle opening distance 500, angle opening distance 750, trabecular iris space 500, trabecular iris space 750 and scleral spur angle, iris bowing and iris shape were measured with AS-OCT by the same examiner.

RESULTS

The differences in all parameters before and after Nd:YAG LPI were statistically significant. Iris configuration was concave in all eyes prior to iridotomy. After Nd:YAG laser iridotomy, the iris configuration became convex in 7 eyes, flat in 9 eyes and remained concave in 7 eyes.

CONCLUSION

Nd:YAG laser peripheral iridotomy is an effective method for reversing the iris concavity and iris bowing in pigment dispersion syndrome.

Recommendations for ultrasound examination in ophthalmology. Part I: Ultrabiomicroscopic examination

Range of ultrasounds used in medical imaging is between 2 and 80 MHz. The highest frequencies are applied in medical imaging of an anterior segment of an eyeball. This paper covers the newest method of ultrasound imaging - an ultrabiomicroscopic examination. Its name reflects resolution which has so far been unavailable, and which allows for imaging a structure of the examined tissues. The article includes basic information about the structure and principles of operation of ultrabiomicroscopic examination tools. Moreover, its position among other methods for echographic examination of an eyeball was determined. Examination techniques and the role of standards of conduct at each stage of a diagnostic procedure were discussed. A role of insufficient cooperation between constructors of new ultrasonographic diagnostic tools and software IT specialist with the users of these tools, which results in the lack of consistency between the components of these sets was emphasized. Based on long term experience in ultrabiomicroscopic examinations, the authors shared observations on practical aspects of this method. Finally, indications and contraindications for ultrabiomicroscopic diagnostics were listed. Introduction of an ultrahigh frequency ultrasound probe allowed for the visualization of an post-iridial area of an anterior segment of an eyeball - an area whose diagnosis is impossible with other diagnostic methods. A wide spectrum of diagnostic indications, which covers both diseases and development anomalies of an anterior segment of an eyeball, confirms a special meaning of this method.

Range of ultrasounds used in medical imaging is between 2 and 80 MHz. The highest frequencies are applied in medical imaging of an anterior segment of an eyeball. This paper covers the newest method of ultrasound imaging – an ultrabiomicroscopic examination. Its name reflects resolution which has so far been unavailable, and which allows for imaging a structure of the examined tissues. The article includes basic information about the structure and principles of operation of ultrabiomicroscopic examination tools. Moreover, its position among other methods for echographic examination of an eyeball was determined. Examination techniques and the role of standards of conduct at each stage of a diagnostic procedure were discussed. A role of insufficient cooperation between constructors of new ultrasonographic diagnostic tools and software IT specialist with the users of these tools, which results in the lack of consistency between the components of these sets was emphasized. Based on long term experience in ultrabiomicroscopic examinations, the authors shared observations on practical aspects of this method. Finally, indications and contraindications for ultrabiomicroscopic diagnostics were listed. Introduction of an ultrahigh frequency ultrasound probe allowed for the visualization of an post-iridial area of an anterior segment of an eyeball – an area whose diagnosis is impossible with other diagnostic methods. A wide spectrum of diagnostic indications, which covers both diseases and development anomalies of an anterior segment of an eyeball, confirms a special meaning of this method.

Quantitative Assessment of Anterior Chamber Parameters in Pigmentary Glaucoma Using Slit-Lamp Optical Coherence Tomography

Purpose.

To quantitatively assess the parameters of anterior chamber and angle dimensions by slit-lamp optical coherence tomography (SL-OCT) in eyes with pigmentary glaucoma (PG).

Methods.

A total of 18 eyes of 11 patients with PG and 18 eyes of 11 healthy volunteers were included in the study. Anterior chamber depth (ACD), anterior chamber volume (ACV), spur distance (internal horizontal anterior chamber diameter), central corneal thickness (CCT), angle opening distance at 500 urn from the scleral spur (AOD 500), and trabecular iris space area at 500 μm from the scleral spur (TISA 500) parameters were detected by SL-OCT. The differences of anterior chamber parameters between patients with PG and the control group were analyzed by Mann-Whitney U test.

Results.

Mean ACD and ACV were measured as 3.28±0.38 mm and 191.6±39.7 mm3 respectively in the PG group. Mean AOD 500 and TISA 500 were 0.88±0.47 mm and 0.29±0.15 mm2 at the nasal angle and 1.14±0.67 mm and 0.41 ±0.23 mm2 at the temporal angle, respectively. Nasal and temporal angles were 49.83±11.1° and 53.83±10.46°. In eyes with PG, the midperipheral iris configuration was found to be considerably concave in 15 eyes (83.3%). Except CCT and spur distance, all anterior chamber dimension and angle parameters detected by SL-OCT were found to be significantly higher in the eyes with PG (Mann-Whitney U test, p<0.05).

Conclusions.

SL-OCT provided highly quantitative data on the parameters of anterior chamber and angle dimensions in PG. The evaluation of the anterior segment anatomy using SL-OCT revealed increased anterior chamber dimensions and posterior bowing of the iris consistent with the increase in angle parameters in patients with PG.

[Role of laser peripheral iridotomy in pigmentary glaucoma and pigment dispersion syndrome: A review of the literature [French version]]

PURPOSE

Pigment dispersion syndrome (PSD) is characterized by a structural abnormality of the posterior surface of the iris causing contact with the zonular fibers. It can lead to an open-angle glaucoma secondary to pigment dispersion into the trabecular meshwork. Laser peripheral iridotomy (PI) has been proposed as a treatment for pigmentary glaucoma (PG) and pigment dispersion syndrome (PDS) by reducing the dispersion of pigment. The goal of this review was to assess the effects of PI for PSD and PG.

METHODS

We included six randomized controlled trials and two cohort studies (286 eyes of 218 participants). Four trials included participants with PG, and 4 trials enrolled participants with PSD with or without elevated intraocular pressure (IOP).

RESULTS

Among patients with PG, at an average of 9 months of follow-up, the mean difference in IOP between groups was 2.69mmHg less in the PI group (95 % CI: -6.05 to 0.67; 14 eyes). In patients with PDS, the average IOP was statistically lower after PI as compared to baseline (Student test, t=11.49, P<0.01). With regard to visual field progression in participants with GP, after an average follow-up of 28 months, the risk of progression was not influenced by PI (RR 1.00 95 %: CI 0.16 to 6.25; 32 eyes). No trials that enrolled patients with PSD showed a diminution of the risk of glaucoma conversion at mid- and long-term.

CONCLUSION

PI decreases the biomechanical factor causing contact between the iris and zonular fibers and may lower IOP over the long-term. Nevertheless, the effects of PI on visual field changes or progression have not been established in PG and PDS. There is no scientific evidence as of yet to advocate PI as a treatment for PDS or PG.

Reverse pupillary block after implantation of a scleral-sutured posterior chamber intraocular lens: a retrospective, open study

BACKGROUND

To report the clinical features of patients with reverse pupillary block (RPB) after scleral-sutured posterior chamber intraocular lens (PC IOL) implantation and biometric changes after laser peripheral iridotomy (LPI).

METHODS

Eight patients attending our hospital's ophthalmology outpatient clinic, who developed RPB after implantation of a scleral-sutured PC IOL due to subluxation of the crystalline lens or IOL, were investigated in this retrospective, observational study.

RESULTS

Preoperative evaluations showed angle pigmentation in all cases and iridodonesis in 2 cases. Two subjects had used an α1A-adrenoceptor antagonist for benign prostatic hyperplasia. Pars plana or anterior partial vitrectomy was performed in all cases. All eyes showed an extremely deep anterior chamber, a concave iris configuration, and contact between the IOL optic and the iris at the pupillary margin. Pupil capture was detected in 2 cases. The mean (± SD) anterior chamber angle (ACA) was 89.91 ± 10.06°, and the anterior chamber depth (ACD) was 4.42 ± 0.16 mm before LPI. After LPI, the iris immediately became flat with a decreased ACA (51.70 ± 2.59°; P = 0.018) and ACD (4.14 ± 0.15 mm; P = 0.012). After LPI, the intraocular pressure decreased from 19.75 ± 3.77 mmHg to 15.63 ± 4.30 mmHg (P = 0.011), and the spherical equivalent decreased from -0.643 ± 0.385 D to - 0.875 ± 0.505 D (P = 0.016).

CONCLUSION

Concomitant vitrectomy, angle pigmentation, and iridodonesis may be risk factors for RPB after scleral-sutured PC IOL implantation. LPI is effective for relieving the RPB.

Update on pigment dispersion syndrome and pigmentary glaucoma

PURPOSE OF REVIEW

The present article reviews the clinical features and pathogenesis of pigment dispersion syndrome and pigmentary glaucoma and provides an update regarding their diagnosis and management.

RECENT FINDINGS

Newer imaging modalities including ultrasound biomicroscopy and anterior segment optical coherence tomography facilitate visualization of the iris concavity characteristic of eyes with pigment dispersion syndrome and pigmentary glaucoma. Patients with pigmentary glaucoma may be distinguished from those with other glaucoma types by the presence of typical symptoms, personality type, and patterns of diurnal intraocular pressure fluctuation. Although laser iridotomy has been shown to alter iris anatomy in pigmentary glaucoma, it is not proven to slow visual field progression. Multiple trials have validated the safety and efficacy of filtering surgery in treating pigmentary glaucoma, with fewer studies published on the role of micro-invasive glaucoma surgery.

SUMMARY

Literature from the review period has further defined the unique clinical characteristics of pigment dispersion syndrome and pigmentary glaucoma. Laser surgery has a limited role in the management of these entities, whereas trabeculectomy remains an acceptable first-line surgical treatment. Further studies are needed to define the potential application of the newer micro-invasive glaucoma procedures in pigmentary glaucoma.

The genetics of pigment dispersion syndrome and pigmentary glaucoma

We review the inheritance patterns and recent genetic advances in the study of pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). Both conditions may result from combinations of mutations in more than one gene or from common variants in many genes, each contributing small effects. We discuss the currently known genetic loci that may be related with PDS/PG in humans, the role of animal models in expanding our understanding of the genetic basis of PDS, the genetic factors underlying the risk for conversion from PDS to PG and the relationship between genetic and environmental--as well as anatomical--risk factors.

Biometric analysis of pigment dispersion syndrome using anterior segment optical coherence tomography

PURPOSE

To compare anterior chamber volume (ACV), iris volume, and iridolenticular contact (ILC) area before and after laser peripheral iridotomy (LPI) in eyes with pigment dispersion syndrome (PDS) using anterior segment optical coherence tomography (AS OCT) and image processing software.

DESIGN

Cross-sectional study.

PARTICIPANTS

Eighteen eyes of 18 patients with PDS; 30 eyes of 30 controls matched for age, gender, and refraction.

METHODS

Anterior segment OCT imaging was performed in all eyes before LPI and 1, 4, and 12 weeks after LPI. At each visit, 12 cross-sectional images of the AS were taken: 4 in bright conditions with accommodation (accommodation), 4 in bright conditions without accommodation (physiological miosis), and 4 under dark conditions (physiologic mydriasis). Biometric parameters were estimated using AS OCT radial sections and customized image-processing software.

MAIN OUTCOME MEASURES

Anterior chamber volume, iris volume-to-length ratio, ILC area, AS OCT anterior chamber depth, and A-scan ultrasonography axial length.

RESULTS

Before LPI, PDS eyes had a significantly greater ACV and ILC area than control eyes (P<0.01) and a significantly smaller iris volume-to-length ratio than the controls (P<0.05). After LPI, ACV and ILC area decreased significantly in PDS eyes, but iris volume-to-length ratio increased significantly (P<0.02) and was not significantly different from that of controls. These biometric changes were stable over time. Iris volume-to-length ratio decreased significantly from accommodation to mydriasis and from miosis to mydriasis, both in PDS and control eyes (P<0.01). In PDS eyes, ILC area decreased significantly from accommodation to mydriasis, both before and after LPI (P<0.01). On multivariate analysis, greater anterior chamber (AC) volume (P<0.02) and larger AC depth (P<0.05) before LPI were significant predictors of a larger ILC area.

CONCLUSIONS

Pigment dispersion syndrome eyes do not have an iris that is abnormally large, relative to the AS size, but have a weakly resistant iris that is stretched and pushed against the lens when there is a pressure difference across the iris.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The role of the lens in pigment dispersion syndrome

In patients with pigment dispersion syndrome, changes of the iris configuration can occur with accommodation, blinking, miotics, and following a laser iridotomy. This observational case series looks at the changes following cataract surgery in 3 eyes with signs of pigment dispersion, symptomatic cataracts, and no previous laser iridotomy that were imaged with optical coherence tomography. The iris was concave posteriorly in dark and light lighting conditions, and became flat following an uncomplicated cataract operation. This may be explained by the elimination of iridolenticular contact, which contributes to the mechanism of reverse pupil block. These iris changes suggest the lens plays an important role in the mechanism of pigment dispersion.

Comparison of internal anterior chamber diameter measured with ultrabiomicroscopy with white-to-white distance measured using digital photography in aphakic eyes

PURPOSE

Measuring the anterior chamber diameter (AC) is important both for diagnostics and before ocular surgery. In clinical practice, horizontal AC diameter is usually estimated on the basis of measurements of corneal diameter (so-called white-to-white [WTW] distance). The usual method for selecting an appropriate size for an AC lens is to add 1 mm to WTW measurement. The purpose of this study was to compare AC diameter measured using ultrasound biomicroscopy (UBM) with WTW distance measured using digital photography in aphakic eyes.

METHODS

The data were gathered prospectively from a nonrandomized consecutive series of aphakic patients. The examined group consisted of 23 eyes of 23 adult patients, mean age 71.17 years. WTW diameter was measured in the 3 o'clock and 9 o'clock meridian on a digital photograph. Internal horizontal AC diameter measurements were performed in the 3 o'clock and 9 o'clock meridian with the Sonomed Ultrabiomicroscopy device with a 50-MHz probe.

RESULTS

Mean horizontal WTW diameter measured using digital photographs was 11.65+/-0.38 mm and mean horizontal internal AC diameter measured using UBM was 13.53+/-0.83 mm. A significant difference in mean WTW diameter measured using digital photography and UBM was found (Mann-Whitney U test, p<0.05). There was a significant correlation between these values (Spearman=0.70, p<0.001).

CONCLUSIONS

In order to obtain good and precise measurements of internal AC diameter, a method of direct visualization of the intraocular structures should be used. Despite the limits of a small case series, our results support the use of UBM technique for preoperative evaluation of the internal AC diameter and AC intraocular lens sizing in aphakic eyes.

Infrared imaging technique may help demonstrate iris transillumination defects in blacks who show other pigment dispersion syndrome clinical signs

PURPOSE

Pigment dispersion syndrome (PDS) is considered to be rare among blacks, although the inability to detect iris transillumination defects (ITDs) among very darkly pigmented irides could diminish the clinician's commitment toward the PDS diagnosis due to uncertainty brought on by the lack of this clinical sign. The goal of this study was to investigate the potential utility of a new infrared (IR) imaging technique to demonstrate ITDs among a group of blacks whose initial PDS diagnosis had to be based on pigment dispersal signs other than iris transillumination.

METHODS

A previously described digital camera system, modified to detect visible and IR light, was used to image the irides of 10 blacks (20 eyes, 8 females, 2 males; age range=51 to 67 y) considered to have PDS on the basis of the clinical signs not including the presence of ITDs as detected with traditional slit lamp examination. Only 1 eye of 2 different subjects had ITDs that were detected with slit lamp examination, but these consisted of a very small, isolated ITD of questionable importance in each of the eyes. Normal control eyes that were matched according to age, race, sex, and refractive error were also photographed, and 2 glaucoma specialists independently reviewed PDS/control eye pairs in a masked fashion. They were instructed to select the eye more likely to be the PDS eye without the benefit of clinical information other than the digital transillumination characteristics.

RESULTS

Observer no. 1 correctly selected the PDS eye among 19 of 20 (95%) PDS-normal eye pairs, and observer no. 2 correctly selected the PDS eye among 15 of 20 (75%) matched pairs. On the basis of these results, it was unlikely that observer no. 1 (Fisher exact test, P<0.0001) or observer no. 2 (P=0.06) selected the PDS eye IR image due to chance alone. It was also unlikely that selection agreement between the 2 observers was due to chance alone (kappa coefficient=0.58).

CONCLUSIONS

Digital IR iris photography may help demonstrate abnormal ITDs among the darkly pigmented irides of blacks who have signs of pigment dispersal but who do not have detectable ITDs with traditional slit lamp examination. Infrared iris examination with newer methods should be studied further relative to blacks and others because useful clinical and/or research oriented information could be gained.

High-speed optical coherence tomography of laser iridotomy

PURPOSE

To describe high-speed (4000 axial scans/s) optical coherence tomography (OCT) findings in a patient with narrow angles.

DESIGN

Interventional case report.

METHODS

A 56-year-old woman was found to have occludable narrow angles on OCT screening. This was confirmed by gonioscopy. Bilateral iridotomy was performed. Imaging of the angles was performed with a high-speed OCT prototype before and after iridotomy.

RESULTS

OCT showed narrow angle bilaterally. Cornea, sclera, scleral spur, trabecula, iris, and iris recess were visualized. After iridotomy, the OCT showed reduction of iris concavity and patent iridotomies. Quantitative measurements of trabecula-iris space area on the OCT images showed widening of the angles to nonoccludable values.

CONCLUSIONS

A 1.3-microm wavelength OCT allows noncontact quantitative assessment of the angle and may be useful in the management of narrow-angle glaucoma.

The Effects of Iridotomy Size and Position on Symptoms Following Laser Peripheral Iridotomy

PURPOSE

To evaluate visual disturbances following laser peripheral iridotomy (LPI). Patients sometimes note visual disturbances following laser peripheral iridotomy. The purpose of this study was to provide what we believe to be the first systematic evaluation of these visual disturbances, including a determination of whether or not they are associated with characteristics of a primary patent laser peripheral iridotomy, such as lid position and size of the iridotomy.

PATIENTS AND METHODS

This was a case series of 93 consecutive (172 eyes) glaucoma patients who had had an Nd: YAG laser peripheral iridotomy. Patients returning for a follow-up visit after laser peripheral iridotomy were selected. A standardized questionnaire was prospectively administered to the study patients at least 1 month after their laser peripheral iridotomy had been performed, inquiring if they experienced any of the following either before or after the iridotomy: halo, lines, crescent, ghost image, glare, spots, shadows, blurring, or other unlisted visual disturbances. On the same visit when they answered the questionnaire, the patients were examined at the slit lamp to assess the location, lid coverage status, and size of the laser peripheral iridotomy. Selection for the performance of the LPI was not prospective. A series of 93 consecutive patients served as controls.

RESULTS

Seven (4%) of the 172 study eyes had postoperative visual symptoms of shadows, ghost images, crescents, or lines. Ninety (52.3%) of the laser peripheral iridotomies were covered by the upper lid, 40 (23%) were completely exposed, and 42 (24%) were partially exposed. Visual disturbances (those listed above plus glare, blurring, haloes, spots, and miscellaneous) occurred in 8 of the 90 (8.9%) eyes with completely covered laser peripheral iridotomies, in 11 of the 42 (26%) with partially covered laser peripheral iridotomies, and in 7 of the 40 (17.5%) with fully exposed LPIs.

CONCLUSION

Visual symptoms following laser peripheral iridotomy are more likely to occur in patients who have partially or fully exposed laser iridotomies than in those in whom the iridotomy is completely covered by the lid.

Pigmented striae of the anterior lens capsule and age-associated pigment dispersion of variable degree in a group of older African-Americans: an age, race, and gender matched study

PURPOSE

To investigate pigmented striae of the anterior lens capsule in African-Americans, a potential indicator of significant anterior segment pigment dispersion.

METHODS

A group of 40 African-American subjects who exhibited pigmented lens striae (PLS) were identified from a non-referred, primary eye care population in Chicago, IL, USA. These subjects were then compared to an age, race, and gender matched control group relative to refractive error and the presence or absence of diabetes and hypertension.

RESULTS

The PLS subjects (mean age = 65.4 +/- 8.8 years, range = 50-87 years) consisted of 36 females and 4 males. PLS were bilateral in 36 (85%) of the 40 subjects. Among the eyes with PLS, 21 (55%) of 38 right eyes and 22 (61%) of 36 left eyes also had significant corneal endothelial pigment dusting, commonly in the shape of a Krukenberg's spindle. Ten (25%) of the PLS subjects had either glaucoma or ocular hypertension (7 bilateral, 3 unilateral). The presence of trabecular meshwork pigment varied from minimal to heavy. The mean +/- SD (range) refractive error of the PLS right eyes was +1.61 +/- 1.43D (-1.50 to +5.00D) and +1.77 +/- 1.37D (-1.00 to +5.00D) for the left eyes. Based on these data, the PLS right eyes were +1.63D (Student's t, p = 0.0001; 95% CI = +0.82 to +2.44D) more hyperopic on average than the control right eyes, and the PLS left eyes were +1.77D (p = 0.0001; 95% CI = +0.92 to +2.63D) more hyperopic on average than the control left eyes. Trend analysis showed a gradually increasing likelihood of PLS with increasing magnitude of hyperopia in both eyes (Mantel-Haenszel chi-square, p = 0.001). Among PLS subjects, 24 (60%) of 40 were hypertensive and 9 (23%) of 40 were diabetic. However, these proportions were not significantly different (two-tailed Fisher's exact test; hypertension: p = 0.30; diabetes: p = 0.70) from the randomly selected controls.

CONCLUSIONS

Among our African-American group, which consisted predominately of females >50 years of age, the likelihood of PLS increased with increasing hyperopic refractive error. This finding is consistent with the possibility that PLS may, in some circumstances, indicate a significant pigment dispersal process due to iris-lens rubbing that may be associated with crowding of anterior segment structures. Additional study is warranted to further assess the nature of PLS, their precise relationship with an age-related pigment dispersal process, and their true significance as a risk factor for development of glaucoma.

Red and/or blonde hair association with pigmentary glaucoma in Israel

PURPOSE

To assess the prevalence of red and/or blonde hair in a defined pigmentary glaucoma (PG) population and to compare their clinical findings with those of PG patients with black or brown hair.

METHODS

Hair color was studied in 35 consecutive PG patients and 35 consecutive primary open angle glaucoma (POAG) patients who served as controls. Patients were classified into red and/or blonde hair group or into black or brown hair group. Clinical characteristics were contrasted between PG patients of red and/or blonde hair with PG patients of black or brown hair.

RESULTS

Of the 35 PG patients, 19 (54.3%) had red and/or blonde hair and 16 (45.7%) had black or brown hair. Of the 35 POAG patients, two (5.8%) had red and/or blonde hair and 33 (94.2%) had black or brown hair. This difference in prevalence of hair color is highly significant (P < 0.001; chi2). Clinical characteristics of the PG patients (age at initial diagnosis, gender, positive family history for glaucoma, initial IOP, refraction, severity of optic nerve damage and prevalence of retinal detachment) were similar in the red and/or blonde hair and the black or brown hair groups.

CONCLUSIONS

A very high prevalence of red and/or blonde hair was found among PG patients in Israel. Should supportive evidence for this association accumulate subsequent to this report, screening of people with these hair colors for PG may be justified.

Keratometry and axial length in pigment dispersion syndrome: a descriptive case-control study

PURPOSE

Pigment dispersion syndrome and pigmentary glaucoma are characterized by loss of pigment from the posterior surface of the iris due to reverse pupillary block. This may be due to an anomalous relation between the position of the globe within the orbit, the axial length of the globe, and the corneal curvature. The authors compared axial length, keratometry, and exophthalmometry in patients with pigment dispersion syndrome and pigmentary glaucoma and in healthy controls.

METHODS

Thirteen pigment dispersion syndrome and pigmentary glaucoma and 17 controls underwent refraction, keratometry, A-scan and exophthalmometry. Patients with pigment dispersion syndrome and pigmentary glaucoma were selected in a university glaucoma practice, and controls were selected for their age and refraction from the staff of the hospital. Both groups were comparable in age and refraction.

RESULTS

Mean age of pigment dispersion syndrome patients and healthy controls was 46.54 and 41.82 years (P = 0.30), respectively, and mean refraction (spherical equivalent) was -4.53 and -4.32 diopters, (P = 0.84), respectively. No statistical differences were noted in axial length measured with A-scan (25.98 and 25.14, P = 0. 15) or anterior chamber depth and lens thickness. The pigment dispersion syndrome and pigmentary glaucoma group had flatter keratometry than the myopic controls. Mean keratometry was 42.39 +/- 1.77 and 44.34 +/- 1.50 (P = 0.003), respectively.

CONCLUSION

The results show that patients with pigment dispersion syndrome have flatter keratometry of approximately 2 diopters compared with age-matched myopic controls. This finding suggests a difference in architecture of the anterior segment.

Exercise and iris concavity in healthy eyes

PURPOSE

To study the effect of exercise on the configuration of the anterior chamber angle in healthy persons.

METHODS

Both eyes of 22 healthy persons were scanned by Ultrasound Biomicroscopy. Before and after 10 minutes of exercise the anterior chamber angle and the area of the peripheral anterior chamber were measured on the scannings.

RESULTS

After exercise the anterior chamber angle/peripheral area increases in all eyes due to changes in the iris configuration. The myopic group shows the largest change.

CONCLUSION

Reverse pupillary block (iris concavity) is not pathognomonic in pigmentary glaucoma, it occurs in all normal eyes after exercise, most pronounced in myopics. Consequently, the difference between physiological and pathological reverse pupillary block has to be clarified.