Pigment dispersion syndrome: a clinical study

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.

[Glaucoma surgery and retinal pathology]

The occurrence of hypertonia during a surgically treated retinal disease is frequent because these disorders often involve the same population of patients. The main cause of postoperative hypertonia remains a preoperative unknown glaucoma. Hypertonia occurring before the treatment of a retinal detachment can result from angle recession glaucoma, ghost cell glaucoma, or Schwartz-Matzuo syndrome; all of which are frequently associated with trauma. Hypertonia occurring after the surgery of a retinal detachment can be caused by scleral buckling, a topical postoperative steroid treatment, or an internal tamponade with gas or silicone. The latter is responsible for severe hypertonia that is frequently resistant to treatment. Hypertonia occurring after the use of triamcinolone is usually controlled with medical treatment. Prior filtrating surgery can lead to technical problems during retinal surgery. The knowledge of pre-existing glaucoma may be reason for cautious management of retinal surgery.

Iris and trabecular meshwork pigment changes after posterior chamber phakic intraocular lens implantation

PURPOSE

To evaluate the changes in laser iridotomies, intraocular pressure (IOP), angle structures, and pupil diameter after implantable contact lens (ICL) (Version 4 Staar Surgical) implantation in myopic Asian eyes.

SETTING

Department of Ophthalmology, Chung-Ang University Yongsan Hospital, Seoul, Korea.

METHODS

The ICL was implanted in 81 eyes of 43 patients with spherical equivalent greater than -6.00 diopters. Gonioscopy examination was performed 1 day after laser iridotomy and 6 and 12 months after ICL implantation. The changes in laser iridotomy sites, IOP, and pupil diameter were also evaluated.

RESULTS

Ten eyes (12.3%) had occlusion or narrowing of the laser iridotomy sites. The angle width was more than 30 degrees in all cases preoperatively but narrowed to less than 20 degrees in 16 eyes (19.8%) 6 months postoperatively. The mean pigment, measured by the semiquantitative method (grade 0 to 4), was 2.03 in the inferior angle, 0.18 in the nasal angle, 0.12 in the temporal angle, and 0.00 in the superior angle 12 months postoperatively. The pigment in all quadrants increased temporally as a result of the laser iridotomy or iris rubbing by the ICL; however, the pigments absorbed gradually and decreased to values before laser iridotomy 12 months postoperatively. There was a temporary increase in IOP from the instillation of steroid eyedrops 1 week and 1 month postoperatively; IOP returned to the preoperative level and remained there 12 months postoperatively. There was a significant decrease in pupil diameter 1 and 3 months postoperatively; the diameter returned to the preoperative size at 6 and 12 months. Pigment dispersion syndrome and pigmentary glaucoma were not seen.

CONCLUSION

Implantation of the ICL narrowed the angle width but did not increase trabecular pigmentation compared with values after laser iridotomy, indicating ICL implantation is safe regardless of the pigmentary changes in the trabecular meshwork.

Genetic context determines susceptibility to intraocular pressure elevation in a mouse pigmentary glaucoma

BACKGROUND

DBA/2J (D2) mice develop an age-related form of glaucoma. Their eyes progressively develop iris pigment dispersion and iris atrophy followed by increased intraocular pressure (IOP) and glaucomatous optic nerve damage. Mutant alleles of the Gpnmb and Tyrp1 genes are necessary for the iris disease, but it is unknown whether alleles of other D2 gene(s) are necessary for the distinct later stages of disease. We initiated a study of congenic strains to further define the genetic requirements and disease mechanisms of the D2 glaucoma.

RESULTS

To further understand D2 glaucoma, we created congenic strains of mice on the C57BL/6J (B6) genetic background. B6 double-congenic mice carrying D2-derived Gpnmb and Tyrp1 mutations develop a D2-like iris disease. B6 single-congenics with only the Gpnmb and Tyrp1 mutations develop milder forms of iris disease. Genetic epistasis experiments introducing a B6 tyrosinase mutation into the congenic strains demonstrated that both the single and double-congenic iris diseases are rescued by interruption of melanin synthesis. Importantly, our experiments analyzing mice at ages up to 27 months indicate that the B6 double-congenic mice are much less prone to IOP elevation and glaucoma than are D2 mice.

CONCLUSION

As demonstrated here, the Gpnmb and Tyrp1 iris phenotypes are both individually dependent on tyrosinase function. These results support involvement of abnormal melanosomal events in the diseases caused by each gene. In the context of the inbred D2 mouse strain, the glaucoma phenotype is clearly influenced by more genes than just Gpnmb and Tyrp1. Despite the outward similarity of pigment-dispersing iris disease between D2 and the B6 double-congenic mice, the congenic mice are much less susceptible to developing high IOP and glaucoma. These new congenic strains provide a valuable new resource for further studying the genetic and mechanistic complexity of this form of glaucoma.

A Cross-Sectional Study of Krukenberg Spindles and Pigmented Lens Striae in a Predominately Black Population

PURPOSE

To investigate the relationship of Krukenberg spindles (KS) and pigmented lens striae (PLS), clinical signs related to iris pigment dispersal and possibly glaucoma.

METHODS

During a 31-month period, 5 practitioners in an urban, primary eye care setting examined consecutive patients for KS and PLS. Multiple logistic regression was used to evaluate relationships among KS, PLS, and other variables.

RESULTS

Krukenberg spindles were present in 65 patients (52 females), comprised of 57 of 2647 (2.2%) blacks, 5 of 303 (1.7%) whites, 2 of 121 (1.7%) Hispanics, and 1 of 55 (1.8%) Asians. PLS were present in 64 subjects (56 females), comprised of 59 (2.2%) blacks, 3 (1.0%) whites, and 2 (3.6%) Asians. KS and PLS were coexistent in 27 subjects. Mean age +/- SD (range) of the KS and PLS subjects was 63.1 +/- 15.0 years (24-88 years) and 67.0 +/- 10.4 years (33-88 years), respectively. Mean refractive error +/- SD (range) of KS and PLS right eyes was +0.55 +/- 2.32D (-6.50 to +5.50D) and +1.34 +/- 2.18D (-6.50 to +7.25D), respectively. Controlling for other variables, PLS were highly predictive (OR = 30.2, P < 0.0001) of KS, and KS were highly predictive (OR = 29.5, P < 0.0001) of PLS. Ignoring presence or absence of PLS, increasing age (in decades) (OR = 1.60, P < 0.0001) was strongly associated with KS. Ignoring presence or absence of KS, age (OR = 1.74, P < 0.0001), female gender (OR = 2.96, P = 0.009), and increasing hyperopic refractive error (OR = 1.30, P < 0.0001) were strongly associated with PLS.

CONCLUSIONS

Krukenberg spindles and PLS were strongly associated in our patient population, and the likelihood of both increased with increasing age. Female gender and increasing hyperopic refractive error were highly significant predictors of PLS.

Relationship between retinal lattice degeneration and open angle glaucoma

Patients with retinal disorders may develop glaucoma of both a primary and secondary type. Pigment may contribute to trabecular obstruction in some patients with open-angle glaucoma. Lattice degeneration of the retina in its typical form is a sharply demarcated, circumferentially oriented, degenerative process with significant alterations of retinal pigmentation. The association between myopia, open angle glaucoma and pigment dispersion is striking. Therefore, it could be postulated that there is significant prevalence of open angle glaucoma in patients with retinal lattice degeneration, especially in combination with myopia.

Ocular genetics: current understanding

Over the past decade, there has been an exponential increase in our knowledge of heritable eye conditions. Coincidentally, our ability to provide accurate genetic diagnoses has allowed appropriate counseling to patients and families. A summary of our current understanding of ocular genetics will prove useful to clinicians, researchers, and students as an introduction to the subject.

Pigment dispersion syndrome and pigmentary glaucoma

BACKGROUND

Pigmentary glaucoma is a common secondary glaucoma that results from pigment being liberated from the posterior iris with subsequent buildup in the trabecular mesh-work. Following this, there is a decrease in aqueous outflow and resultant rise in intraocular pressure.

PURPOSE

While this presentation typically occurs in white myopic males, there is a distinct subtype that occurs in patients of African descent. While there are similarities between the races, there are also significant differences in the clinical presentation of pigmentary glaucoma in white patients and patients of African descent. Iris transillumination defects, corneal endothelial pigment accumulation, and a concave iris-common in whites-are typically absent in patients of African descent.

METHOD

The literature is reviewed in order to summarize pigment dispersion syndrome and pigmentary glaucoma.

Atypical pigment dispersion syndrome in a child

PURPOSE

To describe the features of atypical pigment dispersion in a child.

DESIGN

Observational case report.

METHODS

Retrospective chart review.

RESULTS

An 8-year-old boy presented with midperipheral iris transillumination defects, iris backbowing, heavy pigmentation of the trabecular meshwork, and elevated intraocular pressure. He also had several atypical features including emmetropia, mild posterior subcapsular cataract, small pupils, and peripheral anterior synechiae.

CONCLUSION

Pigment dispersion in childhood is unusual and may have different features from those classically described in adults.

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.

What is the risk of developing pigmentary glaucoma from pigment dispersion syndrome?

PURPOSE

To determine the probability of converting from pigment dispersion syndrome to pigmentary glaucoma.

DESIGN

Retrospective community-based study of all newly diagnosed cases of pigment dispersion syndrome or pigmentary glaucoma.

METHOD

Subjects were patients newly diagnosed with pigment dispersion syndrome or pigmentary glaucoma from 1976 to 1999 in Olmsted County, Minnesota. Criteria for pigment dispersion syndrome were two of three signs: midperipheral, radial iris transillumination defects; Krukenberg spindle; heavy trabecular meshwork pigmentation. Criteria for pigmentary glaucoma were pigment dispersion syndrome and two of three findings: intraocular pressure (IOP) greater than 21 mm, optic nerve damage, or visual field loss. Kaplan-Meier survival curves were used to determine the probability of conversion to pigmentary glaucoma.

RESULTS

A total of 113 patients were newly diagnosed with pigment dispersion syndrome over the 24-year period. Of these, 9 persons developed pigmentary glaucoma or elevated IOP requiring therapy. The probability of converting to pigmentary glaucoma was 10% at 5 years and 15% at 15 years. An additional 23 patients were found to have pigmentary glaucoma at their initial examination. The mean age at diagnosis of pigmentary glaucoma was 42 +/- 12 years; 78% of patients were male, whereas 58% of patients with pigmentary dispersion syndrome glaucoma were male. The most significant risk factor for conversion to pigmentary glaucoma was an IOP greater than 21 mm Hg at initial examination, whereas age, refractive error, and family history of glaucoma were not correlated with conversion.

CONCLUSIONS

The risk of developing pigmentary glaucoma from pigment dispersion syndrome was 10% at 5 years and 15% at 15 years. Young, myopic men were most likely to have pigmentary glaucoma. An IOP greater than 21 mm Hg at initial examination was associated with an increased risk of conversion.

Prevalence of pigmented lens striae in a black population: a potential indicator of age-related pigment dispersal in the anterior segment

PURPOSE

To determine the prevalence of pigmented striae of the anterior lens capsule, with or without associated glaucoma, in a black primary eye care population.

METHODS

Over a 16-month period, five practitioners searched for pigmented lens striae (PLS) among consecutive patients who underwent pupillary dilation during routine eye care provided within the primary care service of an urban eye clinic in Chicago, Illinois.

RESULTS

Meeting the inclusion criteria were 1608 blacks (mean age +/- SD, 40.9 +/- 23.7 years; range, 5 to 100; 1056 females, 552 males). Among the group, 29 (1.8%) subjects had PLS (mean age, 66.5 +/- 11.3 years; range, 33 to 88; 25 females, 4 males). PLS were bilateral 89% of the time. Sixteen of the 29 (55%) blacks had central corneal endothelial pigment dusting (14 bilateral), frequently creating a well-formed Krukenberg's spindle. Trabecular pigmentation varied among the PLS subjects from mild to heavy. Using multiple logistic regression, age (in years) (odds ratio, 1.05; 95% confidence interval, 1.02 to 1.07; p = 0.0003), female gender (odds ratio, 4.46; 95% confidence interval; 1.03 to 19.19; p = 0.045), and hyperopic refractive error (in diopters) (odds ratio, 1.35; 95% confidence interval; 1.09 to 1.67; p = 0.006) were significant predictors of PLS.

CONCLUSIONS

PLS were present in about 1.8% (2.4% females, 0.7% males) of our black population, and they were frequently associated with other signs of intraocular pigment dispersion. Age, female gender, and refractive error were significant predictors for PLS. This is new information that is helpful for understanding a clinical sign that may be an indicator of age-related pigment dispersal within the anterior segment.

Management of glaucoma after retinal detachment surgery

Secondary glaucoma may complicate retinal detachment surgery. Intraocular pressure (IOP) elevation has been described after scleral buckling procedures and vitrectomy with intravitreal injection of gas or silicone oil. Angle-closure glaucoma after scleral buckling develops because of congestion and anterior rotation of the ciliary body. Medical therapy and laser iridoplasty are usually successful in controlling IOP, but the presence of conjunctival scarring and recession and retinal hardware after scleral buckling procedures can make surgical management challenging. Intravitreal injection of expansile gases like sulfur hexafluoride (SF6) and perfluoropropene (C3F8) may produce secondary angle-closure glaucoma with or without pupillary block. Aspiration of a portion of the intraocular gas may be needed, especially if IOP is elevated to a level that may compromise ocular perfusion. Glaucoma also can develop after intravitreal injection of silicone oil secondary to pupillary block, inflammation, synechial angle closure, rubeosis iridis, or migration of emulsified or nonemulsified silicone oil into the anterior chamber. A prophylactic inferior iridectomy at the time of surgery serves to prevent pupillary block. Patients with medically uncontrolled glaucoma after silicone oil injection may require oil removal with or without concurrent glaucoma surgery.

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.

Anterior chamber angle anomalies associated with signs of pigment dispersion in a group of black probands and their first-degree relatives

PURPOSE

To evaluate the presence of iridocorneal angle anomalies associated with signs of pigment dispersion among a group of black probands and their first-degree relatives.

METHODS

Eleven blacks who exhibited pigment dispersion syndrome (PDS) signs, including Krukenberg's spindles, moderate-to-heavy trabecular meshwork pigmentation, and peripheral lenticular/zonular pigmentation, received a complete eye examination that included gonioscopy. Overt iridocorneal angle abnormalities other than pigment deposition were photo-documented. Twenty-two first-degree relatives (6 siblings, 15 children, and 1 parent) of these probands underwent similar examination.

RESULTS

Among the subjects, 5 of 11 probands (age range 13 to 59 years) and 4 of 22 relatives (age range 14 to 51 years) exhibited definite angle anomalies. The nine subjects with angle anomalies belonged to 7 of 11 separate families. The four relatives with angle anomalies did not have PDS according to our criteria, but two other relatives from two additional families did have signs consistent with clinical PDS. Types of angle anomalies included (1) peripheral anterior synechia-like lesions; (2) a prominent concavity of the peripheral iris at the 6-o'clock meridian; (3) a whitish, thread-like band of tissue near the iris base; (4) a prominent, externally-visible Schwalbe's line at the 6-o'clock meridian; and (5) a prominent, web-like confluence of exaggerated iris processes 360 degrees along the angle wall. Iris processes and prominent Schwalbe's lines were not considered abnormal or anomalous unless they were clearly atypical.

CONCLUSIONS

Iridocorneal angle anomalies, other than pigment deposition, were common among our black group who exhibited signs of pigment dispersion as well as among their first-degree relatives. Further consideration should be given to the possibility that among some patient groups, overt goniodysgenesis could be part of a constellation of signs indicative of a pigment dispersion syndrome. Potentially, clinically detectable goniodysgenesis could prove to be a useful marker to identify certain subjects who carry PDS genetic traits but who have not expressed complete phenotypical disease.

Heritage characteristics reported by a group of African-Americans who exhibit the pigment dispersion syndrome: a case-control study

PURPOSE

To investigate the racial heritage of a group of African-Americans who exhibit the pigment dispersion syndrome (PDS).

SUBJECTS AND METHODS

Ten unrelated African-American PDS patients (age range 13-59) from a primary eye care population in Chicago, Illinois, USA, were interviewed to determine their racial heritage. Since Caucasian and Native American heritage were commonly reported, 101 unaffected African-American control subjects (age range 18-55) were also interviewed to determine the reported frequency of these specific racial heritage characteristics.

RESULTS

Some degree of Caucasian heritage was reported by 100% of the PDS subjects and by 46.5% of controls. Native American heritage was reported by 90% of the PDS subjects and by 71.3% of controls. Based on these data, the PDS subjects were significantly more likely to report Caucasian heritage (Fisher's exact test, P=0.001) but they were not significantly more likely to report Native American heritage (P=0.282). In addition, the PDS subjects were significantly more likely to report Caucasian heritage from both parents (P=0.024) and more likely to report a combination of both Caucasian and Native American heritage (P=0.0006) than corresponding controls. In general, the PDS subjects had 'light' or 'medium' complexions.

CONCLUSION

Results from this analysis are consistent with the hypothesis that non-African heritage, particularly Caucasian, is likely to be prevalent in the background of African-Americans who exhibit PDS. It is suggested that non-African heritage may not only be important for the transference of PDS causing genes, but it may also influence factors such as degree of iris pigmentation and rigidity which could influence iris contour and the subsequent expression of PDS in those who are genetically predisposed. Further investigation is needed to study the factors that influence the expression and severity of PDS among African-Americans, a population which traditionally has been considered to be rarely affected by this condition.

The effectiveness of dapiprazole in preventing exercise-induced IOP increase in patients with pigmentary dispersion syndrome

PURPOSE

The authors investigated the use of dapiprazole, an alpha-adrenergic blocking agent, in preventing pigment release and IOP increase after exercise in patients affected with PDS.

METHODS

Three young myopic males (31, 34 and 35 years old) affected with pigmentary dispersion syndrome performed 30 minutes of jogging on a computerized treadmill. Telemetric heartbeat measurement was performed to obtain constant pulse rate training. Computerized tonography and IOP measurement were performed 10 minutes after the exercise. After one month the patients repeated the same exercise after pre-treatment with dapiprazole 0.5% eyedrops (one drop 30, 20 and 10 minutes before the exercise). Ten minutes after the exercise IOP measurements and computerized tonography were repeated.

RESULTS

After 30 minutes of exercise IOP measurements showed values ranging from 19 to 45 mmHg (mean 30.33; SD 8.73). Computerized tonography C values after exercise ranged from 0.04 to 0.16 (mean 0.09; SD 0.04). After pre-treatment with dapiprazole 0.5% eyedrops, IOP values ranged from 18 to 28 mmHg (mean 23.33; SD 3.44) and tonography C values ranged from 0.10 to 0.20 (mean 0.14; SD 0.03).

CONCLUSIONS

The study supports the concept that exercise-induced pigment release temporarily obstructs the acqueous outflow channels, causing IOP increase in some patients with PDS. Pre-treatment with dapiprazole was useful in reducing IOP spikes and in increasing tonographic total outflow facility after exercise. The absence of induced myopia and the lack of dangerous vitreoretinal tractions on retinal periphery make dapiprazole a safe method to reduce exercise-induced pigment dispersion.

A unification hypothesis of pigment dispersion syndrome

PURPOSE

To synthesize recent findings regarding pigment dispersion syndrome in order to arrive at a hypothesis concerning the nature of an underlying genetic predisposition.

METHODS

The literature on the subject was reviewed and analyzed.

RESULTS

Eyes with pigment dispersion syndrome differ from normal in that they have a larger iris, a midperipheral posterior iris concavity that increases with accommodation, a more posterior iris insertion, increased iridolenticular contact that is reversed by inhibition of blinking, possibly an inherent weakness of the iris pigment epithelium, and an increased incidence of lattice degeneration of the retina.

CONCLUSION

A gene affecting some aspect of the development of the middle third of the eye early in the third trimester appears at the present time to be the most likely cause.

Photoreceptor outer segments in aqueous humor: key to understanding a new syndrome

Retinal detachment with oral dialyses and tears of the nonpigmented epithelium of the ciliary body sometimes accompanies aqueous cells and high intraocular pressure with its marked fluctuation. The aqueous cells consist predominantly of photoreceptor outer segments which obstruct aqueous outflow at the trabecular meshwork and induce high intraocular pressure as ghost cells do in ghost cell glaucoma. A new clinical entity with the combination of these signs, namely, rhegmatogenous retinal detachment with "photoreceptor outer segment glaucoma" is designated as Schwartz-Matsuo syndrome in this report. The detection of photoreceptor outer segments in the anterior chamber indicates that a communication between subretinal space and aqueous humor has been established by some mechanism. The new syndrome should be included in differential diagnoses of iritis and glaucoma.

Prevalence of pigment dispersion syndrome in a population undergoing glaucoma screening

The prevalence of pigment dispersion syndrome is thought to be relatively uncommon. Extrapolation of prevalences from glaucoma practices would suggest about 25,000 to 220,000 persons in the United States, an order of magnitude spread. By performing two population screenings that included slit-lamp examination, we detected pigment dispersion syndrome in 18 of 934 individuals. Sixteen of these were white, so that the prevalence of pigment dispersion syndrome in this group was 2.45%. We suggest that many more persons than previously believed may be at risk to develop pigment dispersion.

Argon laser trabeculoplasty in pigmentary glaucoma

PURPOSE

To evaluate the long-term effect of argon laser trabeculoplasty (ALT) in pigmentary glaucoma.

METHODS

The authors retrospectively analyzed results of ALT in 32 eyes of 32 patients with medically uncontrolled pigmentary glaucoma. Data were longitudinally adjusted to normalize the disparity in time of follow-up and evaluated by life-table analysis.

RESULTS

Mean age (+/- standard deviation) was 45.1 +/- 13.1 years (range, 23-72 years) (males, 46.3 +/- 13.7 years; females, 42.9 +/- 12.2 years). Mean baseline intraocular pressure (IOP) was 27.8 +/- 5.3 mmHg. Mean follow-up time was 33.0 +/- 5.0 months (range, 1 week [immediate failures] to 96 months). Three eyes were lost to follow-up at 3 months. Eleven eyes required trabeculectomy between 1 week (2 eyes) and 37 months after laser treatment. Life-table analysis indicated a cumulative success for all eyes of 80% at 1 year, 62% at 2 years, and 45% at 6 years. Mean IOP was significantly reduced (P < 0.001; paired Student's t test) for male and female eyes at all intervals calculated. Age was a significant factor in determining time to failure.

CONCLUSION

Argon laser trabeculoplasty is effective in pigmentary glaucoma. Younger patients had a greater chance of success than older patients at all intervals. This became highly significant (P < 0.001) after 3 years.

Current concepts in pigmentary glaucoma

Since its initial description over 50 years ago as a rare clinical entity, pigmentary glaucoma has become recognized as one of the most common forms of secondary open-angle glaucoma. Pigmentary glaucoma affects a much younger patient population than most other forms of open-angle glaucoma, and has a predilection for Caucasian males with myopia. Hallmarks of this disease include midperipheral iris transillumination defects, Krukenberg spindles and a heavily pigmented trabecular meshwork. The mechanism of pigment dispersion appears to be a rubbing between iris pigment epithelium and packets of lens zonules, possibly associated with an inherent abnormality of the pigment epithelium, and the mechanism of aqueous outflow obstruction is believed to involve accumulation of the pigment granules in the trabecular meshwork, followed by denudation, collapse, and sclerosis of the trabecular beams. Current management includes standard antiglaucoma drugs, laser trabeculoplasty, and filtering surgery, although research suggests the possibility of earlier intervention with medication or surgery to arrest the pigment dispersion and reverse or prevent the secondary glaucoma.

Lattice degeneration of the retina and the pigment dispersion syndrome

Retinal detachment occurs more frequently in patients with pigment dispersion syndrome. We evaluated the incidence of peripheral retinal abnormalities known to predispose to rhegmatogenous retinal detachment in a consecutive series of 60 patients with pigment dispersion syndrome with or without glaucoma. Lattice degeneration was present in at least one eye of 12 patients (20%). Seven patients had bilateral lesions. Full-thickness retinal breaks were found in seven patients (11.7%) and two patients (3.3%) had asymptomatic rhegmatogenous retinal detachments that required scleral buckle procedures. The incidence of lattice degeneration and full-thickness retinal breaks appears to be increased in this group of patients, and may be responsible for the increased risk of rhegmatogenous detachment.

Asymmetric pigmentary glaucoma resulting from cataract formation

Pigment dispersion syndrome usually manifests bilaterally, and asymmetric involvement is unusual. When asymmetry is present, the eye with greater involvement may have an additional exacerbating condition or the eye with less involvement may be protected. Analysis of such cases should further elucidate the mechanism of the disorder and its development and regression. We examined four patients in whom unilateral cataract formation or extraction was associated with reduced clinical signs of pigment dispersion syndrome in the affected eye. Cataract formation, by inducing relative pupillary block, appears to decrease or prevent the manifestation of pigment liberation.

Effects of jogging exercise on patients with the pigmentary dispersion syndrome and pigmentary glaucoma

BACKGROUND

Exercise-induced anterior chamber pigment dispersion with intraocular pressure (IOP) elevation has been reported in patients with the pigmentary dispersion syndrome. Marked pigment dispersion with or without elevation of IOP could predispose these patients to visual field loss. The authors designed this study to evaluate the effects of jogging exercise on anterior chamber pigment and IOP in a group of patients with the pigmentary dispersion syndrome or pigmentary glaucoma.

METHODS

Fourteen subjects with the pigmentary dispersion syndrome, 10 subjects with pigmentary glaucoma, and 10 control subjects underwent a 45-minute protocol of jogging exercise. Anterior chamber pigment was graded and IOP was measured before and up to 3 hours after completion of the exercise protocol.

RESULTS

Eyes of experimental subjects were significantly more likely to develop exercise-induced pigment dispersion than were eyes of control subjects. In experimental subjects, eyes treated with pilocarpine at the time of the study were significantly less likely to develop exercise-induced pigment dispersion than eyes not treated with pilocarpine. In two experimental subjects, pre-exercise treatment with pilocarpine appeared to inhibit exercise-induced pigment dispersion.

CONCLUSIONS

The authors do not believe that all patients with the pigmentary dispersion syndrome or pigmentary glaucoma need to avoid exercise. However, for patients with these disorders who regularly engage in jogging or more strenuous or more jarring types of exercise, they suggest an evaluation before and after the type of exercise in question. If marked exercise-induced pigment dispersion occurs, pilocarpine therapy may be an alternative to avoidance of the exercise.

Quantitative determination of the melanin contents in ocular tissues from human blue and brown eyes

This paper deals with our findings on the quantities of melanin in the tissues from blue and brown eyes. The amount of melanin in the iris, ciliary body and retinal pigment epithelium-choroid was separately determined. The results are expressed as the amount of melanin in mg tissue as well as the amount of melanin in the whole tissue. The results showed that there was no statistically significant difference between the melanin content of the iris in blue and brown eyes. However the ciliary body and retinal pigment epithelium-choroid from brown eyes had more melanin than the corresponding tissues from blue eyes. Blue and brown eyes with higher colour intensity had more melanin than the corresponding eyes with lesser intensity of colour. It is suggested that the differences between brown and blue eyes in their melanin content may have relevance to the pharmacokinetics of drugs that bind to melanin. This would mean that the larger amounts of melanin would decrease the initial levels of the drugs and would increase the drug levels after prolonged periods.

Anisocoria in the pigmentary dispersion syndrome

We studied four patients with anisocoria and the pigmentary dispersion syndrome. In all patients, the larger pupil was on the side of the greater iris transillumination. The amount of anisocoria was between 0.5 and 1.5 mm and was the same in both the light and dark. There was no blepharoptosis, and all pupils dilated normally with cocaine. All of the patients were young men with myopia, and one patient had increased intraocular pressure.

Pigmentary glaucoma in the black population

The pigment dispersion syndrome is associated with a secondary open-angle glaucoma most commonly found in young, myopic, white males. We studied 20 cases (38 eyes) of pigment dispersion syndrome in black individuals as defined by heavy deposition on the corneal endothelium and trabecular meshwork with increased intraocular pressure but no other ocular abnormalities. The 20 patients were a homogeneous group that was typified by older age distribution (average, 73 years), a preponderance of hyperopia (median refraction, +2.15 diopters spherical equivalent), female gender (19 women, one man), no iris transillumination defects (zero of 38 eyes), and flatter iris insertion into the ciliary body. We believe that this homogeneous group of black individuals with pigment dispersion and atypical features represents a pigment dispersion syndrome associated with older age, hyperopia, and female sex preponderance, in the black race.

Risk factors for the development and severity of glaucoma in the pigment dispersion syndrome

The medical records of 93 patients with pigmentary glaucoma and 18 patients with pigment dispersion syndrome were studied with regard to factors associated with the presence and severity of secondary glaucoma within this population. Male gender, black race, severe myopia, and Krükenberg spindles were identified as possible risk factors. Men were predominant in this population 75 (67.6%); the diagnosis was made in men at an earlier age; they had a higher proportion in the glaucoma group; and they required more aggressive glaucoma therapy. There were only four black patients, but all required surgery. Patients in the glaucoma group had significantly more severe myopia and a higher incidence of Krükenberg spindles. These risk factors may help to identify which patients with the pigment dispersion syndrome require closer follow-up or the possible initiation of prophylactic therapy.

Pigment dispersion syndrome in pseudophakic corneal transplants

We observed the pigment dispersion syndrome in two patients after keratoplasty with posterior chamber intraocular lenses. In addition to a heavily pigmented trabecular mesh-work and iris transilluminating defects, an inferior linear pigmented endothelial line was seen in both patients. One patient developed glaucoma, which was well controlled with medication. Pigment dispersion syndrome in patients with penetrating keratoplasty should not be confused with an allograft reaction but should alert the transplant surgeon that a different process is occurring.

Long-term analysis of pigmentary dispersion syndrome and pigmentary glaucoma

A retrospective, longitudinal study of 129 eyes in 65 patients with pigmentary dispersion syndrome and either ocular hypertension of glaucoma was undertaken. The mean follow-up period was 17 years (range, 5-35 years). Visual acuity, intraocular pressure (IOP), visual field loss, pigment grade, Krukenberg spindle, iris transillumination, medications, and surgeries were analyzed for each patient at 5-year intervals from 1960 through 1983. Disc and field changes developed in 35% of patients with pigment dispersion syndrome and ocular hypertension during the study period. The long-term prognosis of the medical and surgical management of pigmentary glaucoma is discussed.

Fluorescein angiography of the iris in anterior segment pigment dispersal syndrome

The results are presented of fluorescein angiography of the iris in 11 patients with anterior segment pigment dispersal syndrome. These show a general hypovascularity of the iris with fine neovascularisation at the pupil margin and the peripupillary area. Hypoplasia of the iris stroma was also present in many cases. When the condition was virtually unilateral, the vascular changes were present though less marked in the relatively unaffected eye. It is postulated that the anterior segment pigment dispersal syndrome is secondary to a congenital mesodermal deficiency of the iris stroma with hypovascularity of the iris, which forms a poor support tissue for the pigment epithelium of the iris, resulting in shedding of pigment granules particularly in the region of the attachment of the dilator muscle to the pigment epithelium. The condition may be hereditary. Because of the hypovascularity the mesodermal hypoplasia may be progressive, but pigment release may diminish in later life with treatment, with consequent diminution of pupil activity.

Pigmentary glaucoma: a clinical review of anterior segment pigment dispersal syndrome

Sixty-eight cases (44 males, 24 females) of anterior segment pigment dispersal syndrome are reviewed. Five patients had no rise in intraocular pressure, 38 had ocular hypertension and 25 had glaucoma as shown by optic disc cupping and field loss. All cases had heavy deposition of pigment in the drainage angle together with Krukenberg spindles and/or light reflux through the iris. Other evidence of anterior segment pigment dispersal was common. The condition was commonest in young adult males, but could present at any age and in women. Medical treatment was often successful initially, but continued to control pressure in only 17 of 42 patients. Laser trabeculoplasty helped some patients. Drainage operations of various types were successful in 19 of 23 cases. Iris angiography showed evidence of vascular hypoperfusion of the iris which probably precedes pigment dispersal and suggests that the ultimate aetiology may be a congenital deficiency of the mesodermal support tissues of the iris. Some degree of iris stromal atrophy is also common and may become marked. Pigment dispersal from the pigment epithelium of the iris occurs in susceptible individuals and may be associated with the insertion of the dilator muscle. The term anterior segment pigment dispersal seems appropriate as the condition is limited to the anterior segment.

Pigmentary open-angle glaucoma secondary to posterior chamber intraocular lens implantation and erosion of the iris pigment epithelium

This report describes two patients who developed a secondary form of pigmentary open-angle glaucoma after implantation of a posterior chamber intraocular lens. The glaucoma was associated with considerable erosion of the iris pigment epithelium and a charcoal-black pigmentation of the trabecular meshwork. One case responded to argon laser trabeculoplasty and the other case did not. Possible causes of this syndrome are discussed.