Late postoperative opacification of hydrogel intraocular lenses: analysis of 13 explanted lenses

PURPOSE

We report the clinical, morphological, and ultrastructural findings of 13 consecutively explanted opacified Hydroview(R) (hydrogel) intraocular lenses (IOLs). Our purpose was to provide a comprehensive account on the possible factors involved in late postoperative opacification of these IOLs.

PATIENTS AND METHODS

Thirteen consecutive opacified hydrogel IOLs (Hydroview H 60 M, Bausch & Lomb) were explanted due to the significant visual impairment they caused. The IOLs underwent macroscopical examination, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electrophoresis for protein detection. Three unused control Hydroview IOLs served for comparison.

RESULTS

Macroscopical examination showed a diffuse or localized grey-whitish opacification within the IOL optic. TEM confirmed the presence of lesions inside the optic in all the explanted IOLs and revealed 3 patterns of deep deposits: a) diffuse, thick, granular, electron-dense ones; b) small, thin, lattice-like ones, with prominent electron-lucent areas; and c) elongated electron-dense formations surrounded by electron-lucent halos. SEM showed surface deposits on four IOLs. EDS revealed oxygen and carbon in all IOLs and documented calcium, phosphorus, silicon and/or iron in the deposits. Two of the patients with iron in their IOLs had eye surgery prior to their phacoemulsification. Iron correlated well with the second TEM pattern of deep lesions, whereas calcium with the third TEM pattern. No protein bands were detected on electrophoresis. Control lenses did not show any ultrastructural or chemical abnormality.

CONCLUSIONS

The present study supports the presence of chemical alterations inside the polymer of the optic in late postoperative opacification of Hydroview IOLs. This opacification does not follow a unique pathway but may present under different ultrastructular patterns depending on the responsible factors. Mechanical stress during surgery may initiate a sequence of events where ions such as calcium, phosphorus, silicon, and/or iron, participate in a biochemical cascade that leads to gradual alteration of the polymer network. Intraocular inflammation due to previous operation may be a factor inducing opacification through increase of iron-binding capacity in the aqueous humour. Calcification accounts only partially for the opacification noted in this type of IOL.

Evaluation of the acoustic function in pseudoexfoliation syndrome and exfoliation glaucoma: audiometric and tympanometric findings

PURPOSE

Previous studies have reported increased audiometric thresholds in patients with pseudoexfoliation syndrome (XFS), compared with normative data. This study examines mean audiometric thresholds and tympanometric peak values in patients with XFS and in a control group.

METHODS

This is a prospective, nonrandomized control case study. Patients with XFS in one or both eyes constituted the study group (SG). Patients without XFS in either eye constituted the control group (CG). Patients with a history of conditions affecting hearing function were excluded. The SG and the CG included 54 and 48 patients, respectively. Pure tone hearing thresholds levels were measured at 0.25, 1, 2, 3, and 8 kHz. Tympanometric peak values were also recorded. Differences in audiometric mean threshold values and tympanometric peak values between SG and CG, as well as between glaucomatous and nonglaucomatous eyes, were examined.

RESULTS

Bone and air audiometric thresholds were significantly increased in SG for 3 kHz and 8 kHz but not for 0.25 kHz, 1 kHz, and 2 kHz. Tympanometric peak values were significantly lower in SG compared with CG. In SG, glaucomatous patients had significantly higher air-conduction thresholds for 3 kHz and 8 kHz. Differences in bone and air audiometric findings as well as tympanometric findings between glaucomatous and nonglaucomatous patients were statistically not significant in CG.

CONCLUSIONS

The results agree with previous reports on sensorineural hearing loss in XFS. The reduced tympanometric peak values in SG imply impairment in the elastic properties of the middle ear in XFS. The findings provide additional evidence for the systemic nature of XFS.

Transforming and insulin-like growth factors in the aqueous humour of patients with exfoliation syndrome

BACKGROUND

Growth factors circulating with the aqueous may play an important role in the pathogenesis of exfoliation syndrome (XFS), which is characterized by excessive synthesis and accumulation of abnormal extracellular material.

METHODS

We investigated the concentration of three ubiquitous growth factors (TGF-beta1, TGF-beta2 and IGF-1) in the aqueous humour of 50 patients with XFS (27 from Erlangen, 23 from Thessaloniki) and 54 age-matched controls (27 from Erlangen, 27 from Thessaloniki). This study was performed in two centres, independently of each other, using different assay systems.

RESULTS

In the aqueous humour samples collected in Erlangen, both the levels of total TGF-beta1 (P<0.001) and mature TGF-beta1 (P<0.05) were significantly increased in XFS patients compared with controls. Specifically, for total TGF-beta1 patients with XFS exhibited higher a mean value (90.5 +/- 37.4 pg/ml) than controls (30.2 +/- 8.3 pg/ml). The mean level of mature TGF-beta1 was also higher in XFS (14.2 +/- 2.8 pg/ml) than in controls (4.9 +/- 5.5 pg/ml). No difference was found between XFS and controls in the levels of total or mature TGF beta2 in the aqueous or in the level of these two growth factors in the serum. In aqueous humour samples collected in Thessaloniki a significant difference between XFS and controls was also observed for mature TGF-beta1 (XFS 17.06 +/- 11.02 pg/ml vs controls 9.01 +/- 5.69 pg/ml; P=0.006). No difference was observed in TGF-beta2 concentration or IGF-1 concentration in the aqueous. No correlation could be established between protein concentration and the levels of the three growth factors measured. A significant correlation was found between age and protein concentration in XFS, but not in the controls.

CONCLUSION

Since TGF-beta1 induces the synthesis and accumulation of extracellular matrix, it is hypothesized that TGF-beta1 plays an important role in the pathogenesis of XFS. Our data suggest that the increased levels of TGF-beta1 are most likely due to enhanced local synthesis.

Brimonidine 0.2% given two or three times daily versus timolol maleate 0.5% in primary open-angle glaucoma

PURPOSE

To evaluate the efficacy and safety of brimonidine 0.2% two or three times daily versus timolol maleate 0.5% solution twice daily.

METHODS

Patients with primary open-angle glaucoma were randomized by Latin square technique to one of the three treatment sequences in this crossover, prospective double-masked trial. Each treatment period consisted of 6 weeks of chronic dosing followed by a diurnal curve for the intraocular pressure measured at 08:00, 10:00, 16:00, 18:00, 20:00, 22:00, and 24:00 hours. Intraocular pressure was measured by applanation tonometry.

RESULTS

Thirty patients completed this trial. The average diurnal intraocular pressures in the trial were measured for timolol maleate (17.7 +/- 2.7 mm Hg), brimonidine given three times daily (18.0 +/- 2.2 mm Hg), and brimonidine given twice daily (19.2 +/- 2.4 mm Hg). There was a statistical difference between groups (P <.005). When groups were compared by pairs, three times daily dosing with brimonidine and timolol maleate both reduced the pressure more than twice daily brimonidine at every time point past 10:00 hours and for the diurnal curve (P <.05). In contrast, three times daily brimonidine and timolol maleate were statistically similar for the diurnal pressure, and each time point, except timolol maleate, decreased the pressure more at 16:00 (P =.042). Safety was similar between groups.

CONCLUSIONS

This study demonstrated that both timolol maleate twice daily and brimonidine three times daily provide a similar intraocular pressure reduction to each other. Timolol maleate twice daily and brimonidine three times daily provide a greater decrease in pressure in the late afternoon and nighttime hours, compared with brimonidine twice daily.

Twenty-four hour intraocular pressure reduction with latanoprost compared with pilocarpine as third-line therapy in exfoliation glaucoma

PURPOSE

To compare the 24 hour efficacy of latanoprost 0.005% given every evening with that of pilocarpine 4% given four times daily as third-line therapy in patients with exfoliation glaucoma receiving timolol 0.5% and dorzolamide 2% each given twice daily.

METHOD

We enrolled 30 patients with exfoliation glaucoma not adequately controlled on timolol maleate 0.5% and dorzolamide 2%. Each patient underwent a baseline 24 hour intraocular pressure curve testing at 06:00, 10:00, 14:00, 18:00, 22:00 and 02:00 hours. Patients were randomised to receive either latanoprost 0.005% or pilocarpine 4% for a minimum of 8 weeks and were then crossed over to the opposite therapy. Diurnal curve testing was repeated at the end of each treatment.

RESULTS

There was a significant decrease from baseline in intraocular pressure at each timepoint for both study medicines (p < 0.016). Latanoprost provided better intraocular pressure control than pilocarpine at daytime measuresments (17.4 vs 19.7 mmHg at 06:00 hours, p < 0.001; 17.8 vs 19.1 mmHg at 10:00 hours, p = 0.04). However, pilocarpine reduced the pressure more than latanoprost at 22:00 hours (18.4 vs 19.5 mmHg, p = 0.016). Overall, the diurnal intraocular pressure was reduced from a baseline of 21.5 +/- 3.7 mmHg to 18.8 +/- 3.1 mmHg on pilocarpine and to 18.0 +/- 3.0 mmHg on latanoprost (p = 0.06). In addition, mean peak pressure was similar between pilocarpine (21.0 +/- 2.9 mmHg) and latanoprost (20.5 +/- 3.8 mmHg) (p = 0.20). Side-effects were similar with the exception of blurred vision, which was only found with pilocarpine (10%). Compliance was more difficult with pilocarpine.

CONCLUSION

In exfoliation glaucoma, as a third-line adjunctive therapy added to timolol and dorzolamide, latanoprost and pilocarpine have similar diurnal efficacy. However, latanoprost provides a greater morning pressure reduction.

Compliance and viewpoint of glaucoma patients in Greece

PURPOSE

To document the prevalence of non-compliance and to investigate patients' perceptions concerning glaucoma in a Greek cohort.

METHODS

We investigated 100 consecutive patients referred to our glaucoma clinic and already treated for chronic glaucoma. Compliance and patients' insight were ascertained by two independent observers by means of a predetermined questionnaire. All patients were subsequently assessed for their ability to instil their eyedrops accurately.

RESULTS

Fifty one per cent of our patients were not aware of the nature of glaucoma, but 80% were afraid it might lead to blindness. Clinically significant non-compliance (more than two doses missed per week) was established in 44% of our patients. Men and those using eyedrops more than 4 times a day were more likely to default. Non-compliant patients exhibited higher mean intraocular pressure (22.9 vs 18.5 mmHg; p > 0.001) and worse visual field loss (10.8 vs 7.0 dB; p = 0.008) compared with compliant patients. Involuntary non-compliance was also common in our group, with only 53% instilling their eye drops accurately.

CONCLUSION

Non-compliance is a significant limiting factor in glaucoma therapy in Greece.

Increased growth factor activity in the aqueous humour of patients with exfoliation syndrome

BACKGROUND

To investigate the growth factor activity in the aqueous humour of patients with exfoliation syndrome (XFS).

METHODS

We collected 154 aqueous humour samples (69 from patients with XFS and 85 from age-matched controls) prior to routine extracapsular cataract surgery. Growth factor activity was investigated using a [3H]thymidine incorporation assay on McCoy cells that assesses DNA synthesis. Albumin concentration was measured by a radio-immunoassay as an index of blood aqueous barrier integrity. N-Acetylglucosaminidase (NAG) activity, a marker of cellular breakdown, was ascertained by a fluorometric method.

RESULTS

XFS aqueous samples exhibited significantly higher growth factor activity than to the control samples (P<0.001). Albumin concentration was also higher in the XFS group. NAG activity was similar in the two groups. No relationship between growth factor activity and the other parameters investigated was found.

CONCLUSIONS

Increased growth factor activity was detected in the aqueous humour of patients with XFS. This finding may be related to the pathogenesis of XFS.

Comparison of the efficacy and safety of latanoprost 0.005% compared to brimonidine 0.2% or dorzolamide 2% when added to a topical beta-adrenergic blocker in patients with primary open-angle glaucoma or ocular hypertension

The purpose of this study was to evaluate the ocular hypotensive efficacy and safety of latanoprost 0.005% (Xalatan, Pharmacia & Upjohn), brimonidine (Alphagan, Allergan), and dorzolamide (Trusopt, Merck Inc.) when added to a beta-blocker in patients with ocular hypertension or primary open-angle glaucoma. This was a multicenter, retrospective analysis which included all reviewed patient records in which latanoprost, brimonidine or dorzolamide were added to a beta-blocker for at least three months. Patients who were treated for less than three months, who failed therapy due to ineffectiveness of the medicine or an adverse event also were included. The study included 141 patients. Latanoprost (n = 50) showed an intraocular pressure of 16.7 +/- 3.3 mm Hg (-6.3 +/- 4.1 mm Hg, P < 0.001), brimonidine (n = 24) 17.4 +/- 4.9 mm Hg (-4.2 +/- 4.5 mm Hg, P < 0.001), and dorzolamide (n = 67) 20.1 +/- 6.1 mm Hg (-3.1 +/- 5.1 mm Hg, P < 0.001) at three months. A significant difference was observed in the absolute level of intraocular pressure (P < 0.005) and the change from baseline between groups (P < 0.005) at three months. A significant difference was observed between groups in the success rate of therapy between latanoprost (70%), brimonidine (58%) and dorzolamide (40%) (P = 0.008). No significant differences were observed between groups for rate or type of adverse events leading to discontinued therapy. This study showed that latanoprost, when added to beta-blockers, compares favorably in ocular hypotensive efficacy and is similar in safety to brimonidine and dorzolamide.

Contact lens fitting difficulties following refractive surgery for high myopia

PURPOSE

To describe the clinical and optical problems encountered in contact lens fitting following refractive surgery for high myopia.

METHODS

Following refractive surgery for high myopia (greater than -10.00 D) we corrected residual refractive errors with contact lenses in the four eyes of two patients. The first patient had undergone bilateral laser in situ keratomileusis (LASIK),with two subsequent LASIK retreatments in the left eye. Ten months later she was fit with rigid gas permeable (RGP) lenses in both eyes. The second patient had undergone a clear lens extraction in the right eye and radial keratotomy followed by photorefractive keratectomy(PRK) in the left eye. She was fit with toric soft lenses six years postoperatively.

RESULTS

Final visual acuity obtained with contact lenses was 20/25-20/20 in all eyes. The first patient required significant minus lens power compensation. Furthermore, the RGP lens in the left eye was slightly decentered due to corneal irregularity induced by LASIK. The second patient had regular corneal surfaces and was successfully fit with daily wear toric soft lenses despite the 2.75 D of residual astigmatism in the left eye.

CONCLUSIONS

Following refractive surgery for high myopia a proportion of patients will remain undercorrected. In these patients the alterations in corneal architecture that ensue make contact lens fitting more challenging. Patients with regular astigmatism may be fitted successfully with toric soft lenses. Patients with corneal irregularities should be fit with RGP lenses.

Twenty-four hour control of intraocular pressure with dorzolamide and timolol maleate in exfoliation and primary open-angle glaucoma

PURPOSE

To determine the efficacy and safety of adding dorzolamide 2% twice daily to timolol maleate solution 0.5% twice daily when treating exfoliation glaucoma or primary open-angle glaucoma.

METHODS

This was a single-centre, crossover intra-individually controlled comparison. Sixty-two consecutive patients (31 with exfoliation glaucoma and 31 with primary open angle glaucoma) chronically treated with timolol maleate twice daily were included in this trial. Patients then had added dorzolamide 2% twice daily (08:00 and 20:00), instilled approximately 10 min after timolol maleate. Patients underwent diurnal intraocular pressure (IOP) testing (six measurements over 24 h), first on timolol maleate monotherapy and 2 months later following the addition of dorzolamide 2% as adjunctive therapy.

RESULTS

On timolol monotherapy patients with exfoliation glaucoma had a higher mean IOP at 02:00, 06:00, 10:00, 14:00 and 22:00 hour time points as well as a higher maximum, minimum and range of IOP throughout the day compared with the primary open-angle glaucoma group (p < 0.05). Following the addition of dorzolamide as adjunctive therapy to timolol maleate there was a significant reduction in IOP (p < 0.05) at all time points in both glaucomas, but mean IOP at 10:00, 14:00, 18:00 and 22:00 hour time points, as well as the peak and range of IOP, remained higher in the exfoliation glaucoma group. No serious adverse events were noted with dorzolamide. Bitter taste, the most common symptom, was noted in 30% of patients.

CONCLUSIONS

These data suggest that dorzolamide 2% used adjunctively with timolol maleate 0.5% solution is effective in reducing diurnal IOP in patients with primary open-angle and exfoliation glaucoma but does not alter the characteristics of higher IOP levels in the latter disease.

Comparison of 24 hour control with Timoptic 0.5% and Timoptic-XE 0.5% in exfoliation and primary open-angle glaucoma

PURPOSE

To compare the 24 hour intraocular pressure (IOP) curve in exfoliation glaucoma (EXG) and primary open-angle glaucoma (POAG) patients treated first with timolol solution 0.5% (TS) twice daily and then with timolol maleate gel forming solution 0.5% (TXE) once daily.

METHODS

We prospectively investigated age-matched, newly diagnosed EXG (n = 25) and POAG (n = 25) patients who were admitted as in-patients for 24 hour phasing first with TS and then TXE.

RESULTS

Generally TS and TXE controlled both POAG and EXG patients in a similar fashion. However, a trend to lower pressures was observed in both EXG and POAG patients with TS therapy. At two time points (10:00 and 22:00) in POAG patients, TS (18.4 +/- 3.7 and 17.2 +/- 3.1 mm Hg, respectively) provided lower intraocular pressures than TXE (19.8 +/- 3.5 and 18.9 +/- 3.8 mm Hg, respectively) (p < 0.05).

CONCLUSION

Both TS twice daily and TXE once daily control POAG and EXG generally to a similar extent.

Loss of iridolenticular contact in eyes with exfoliation syndrome may protect against glaucoma

PURPOSE

To provide evidence for the hypothesis that dynamic iridolenticular contact predisposes to the development of glaucoma in exfoliation syndrome (XFS).

METHODS

We present four patients with bilateral XFS and unilateral exfoliation glaucoma (XFG) whose normotensive eyes had suffered traumatic loss of dynamic iridolenticular contact.

RESULTS

All 4 patients had bilateral XFS and developed XFG only in the untraumatized eyes. One patient had loss of iridolenticular contact in the traumatized eye, two had a nonreactive pupil, and one had had intracapsular cataract extraction at age 28.

CONCLUSIONS

Loss of dynamic iridolenticular contact may help to protect against development of glaucoma in eyes with XFS.

Comparison of 24-hour intraocular pressure reduction with two dosing regimens of latanoprost and timolol maleate in patients with primary open-angle glaucoma

PURPOSE

To compare the 24-hour diurnal ocular hypotensive efficacy of two dosing regimens of latanoprost, once daily (8 AM or 10 PM), vs timolol maleate, twice daily.

METHODS

We measured six diurnal intraocular pressure curves (6 AM, 10 AM, 2 PM, 6 PM, 10 PM, and 2 AM) in one randomly selected eye of 34 Greek patients newly diagnosed with primary open-angle glaucoma. The first diurnal curve was an untreated baseline. Patients began taking timolol 0.5%, twice daily, for 2 months. Patients were randomly assigned to latanoprost 0.005% given at 8 AM or 10 PM for 1 month and then changed to the other dosing regimen for 1 month. A diurnal curve was performed after each dosing period.

RESULTS

The baseline diurnal pressure for all 34 subjects was 23.1 +/- 3.7 mm Hg. The average intraocular pressures at 6 AM for patients who were given latanoprost in the evening (17.9 +/- 2.9 mm Hg) was statistically lower than that in patients given timolol solution (20.1 +/- 2.5 mm Hg, P = .003); however, patients who were given timolol demonstrated a similar diurnal intraocular pressure (19.1 +/- 2.8 mm Hg) to both morning (18.8 +/- 3.7 mm Hg) and evening doses (18.8 +/- 3.6 mm Hg) of latanoprost (P =.329). When the two latanoprost dosages were compared directly, evening administration provided a statistically lower intraocular pressure at 10 AM (P = .0001) and morning administration at 10 PM (P = .0001). This study had an 80% power to exclude a 1.2-mm Hg difference between groups.

CONCLUSIONS

This study indicates that in a small population, both latanoprost and timolol are effective in lowering intraocular pressure throughout a 24-hour period; however, latanoprost is most effective in the 12-hour to 24-hour period after administration.

The comparative ocular hypotensive effect of apraclonidine with timolol maleate in exfoliation versus primary open-angle glaucoma patients

PURPOSE

To compare the effect of adding apraclonidine 0.5% to timolol maleate 0.5% in patients with exfoliation versus primary open-angle glaucoma. Since exfoliation glaucoma is known to demonstrate higher pressures than primary open-angle glaucoma on timolol maleate therapy alone, the authors wished to determine whether apraclonidine equalised the intraocular pressure (IOP) between these two glaucomas when added to timolol maleate.

METHODS

We age-matched 30 consecutive exfoliation and 30 primary open-angle glaucoma patients who had an IOP > or = 22 mmHg on timolol maleate alone. Patients underwent IOP diurnal curve testing on timolol maleate twice daily alone and, 2 months later, following the addition of apraclonidine 0.5% three times daily. Statistical analysis of the IOP at each time point was by an unpaired t-test between groups. A paired t-test was used to evaluate the reduction in IOP from baseline within groups after the addition of apraclonidine.

RESULTS

On timolol maleate alone, exfoliation patients had a higher mean IOP at 06:00 and 10:00 hours as well as a higher peak, range and standard deviation of the IOP compared with primary open-angle glaucoma patients (p < 0.05). Following the addition of apraclonidine the mean, peak and range of IOP were statistically similar between groups and only the standard deviations remained higher in the exfoliation glaucoma group (p < 0.001). The mean diurnal IOP after apraclonidine was added was 20.5 +/- 7.0 mmHg in the exfoliation glaucoma group and 20.0 +/- 3.4 mmHg in the primary open-angle glaucoma group, which was not significantly different between groups (p = 0.73).

CONCLUSIONS

This study suggests that apraclonidine 0.5% used adjunctively with timolol maleate 0.5% solution is associated generally with similar IOP control in exfoliation and primary open-angle glaucoma patients.

The role of computerized corneal topography in rigid gas permeable contact lens fitting

PURPOSE

The purpose of this study was to determine the clinical utility of computerized corneal topography (CCT) in the fitting of rigid gas permeable (RGP) contact lenses.

METHODS

In this prospective study, we compared the clinically determined parameters to those obtained by CCT in 50 consecutive patients who underwent RGP lens fitting. The TMS-1 program was used for CCT, and we fit patients with Boston RGP contact lenses (type II, or Equalens). The final decision on the RGP lenses dispensed relied upon the clinical evaluation (slit lamp examination, fluorescein pattern, lens centration, and visual acuity).

RESULTS

The base curve of RGP lenses proposed by CCT was similar to that selected clinically (mean: 7.74 mm versus 7.81 mm). However, the mean diameter of the CCT proposed lenses was smaller than that selected clinically (9.31 mm versus 9.6 mm, P < 0.01). Divergence was more pronounced in keratoconus.

CONCLUSIONS

CCT is an important tool in RGP contact lens fitting. Clinical evaluation remains mandatory in determining the appropriate RGP lens.

Preoperative features of patients with exfoliation glaucoma and primary open-angle glaucoma. The AHEPA study

PURPOSE

To describe and compare the preoperative characteristics of Greek patients with exfoliation glaucoma (EXG) and primary open-angle glaucoma (POAG).

METHODS

We prospectively investigated the preoperative features of 100 consecutive patients undergoing filtration surgery for either EXG, or POAG. We compared 74 patients with EXG and 26 with POAG.

RESULTS

EXG patients were older (68.2 vs 62.4 years; p<0.05) and more often from the countryside (73%). Both glaucomas showed a preponderance for males, similar frequencies of positive family history and systemic disorders, with the exception of diabetes which was more common in POAG (19.2% vs 5.4%). The first IOP measurement, before treatment, was significantly higher in EXG (40.4 mm Hg) compared with POAG (33.9 mm Hg). Despite a shorter duration of medical therapy (25 vs 65 months) and more topical drugs EXG patients exhibited higher mean preoperative IOP (36 vs 27.8 mm Hg for POAG; p<0.05). EXG patients had significantly worse visual acuity than POAG (0.4 vs 0.6; p<0.05) and worse compliance to medical therapy (48%) compared to POAG (33%).

CONCLUSION

Significant differences in preoperative features distinguish EXG from POAG.

Effect of timolol on the diurnal intraocular pressure in exfoliation and primary open-angle glaucoma

OBJECTIVE

To describe and compare the diurnal intraocular pressure (IOP) variation in patients with exfoliation glaucoma (EXG) and primary open-angle glaucoma (POAG) who were treated with a solution of timolol maleate (0.5%) twice daily.

DESIGN

Consecutive Greek patients who were newly diagnosed as having EXG or POAG were prospectively investigated; they underwent 24-hour diurnal IOP measurements first without therapy and then 6 months afterward while they were being treated with timolol maleate (0.5%). After matching for age, 38 pairs of patients with these 2 types of glaucoma were compared.

RESULTS

Untreated patients with EXG had significantly higher IOP values for all time points assessed and a greater mean range of IOPs (11.8 mm Hg for EXG vs 7.6 mm Hg for POAG; P < or = .001). Following therapy with timolol maleate (0.5%) given twice daily, patients with EXG had higher IOP values for the measurements that were obtained at 6 and 10 AM, 10 PM, and 2 AM, a higher mean range of IOPs (7.0 mm Hg for EXG vs 5.6 mm Hg for POAG; P = .03), and a higher maximum IOP (mean, 24.9 mm Hg for EXG vs 20.9 mm Hg for POAG; P = .003). The reduction of the range of diurnal variation of IOP was more pronounced in patients with EXG than in patients with POAG (40% vs 26%; P = .04). Twenty-two (58%) of 38 patients with EXG and 20 (53%) of 38 patients with POAG had peak IOP values that were found outside office hours. Only 5 (13%) of the patients with EXG exhibited an IOP of 18 mm Hg or less at all time points compared with 12 (32%) of the patients with POAG (P = .05).

CONCLUSION

Despite a greater initial IOP reduction in the patients with EXG treated with timolol, a higher IOP and significant fluctuation in the diurnal curve of IOP during the time in which patients received therapy still characterized EXG from POAG.

Exfoliation syndrome in a 17-year-old girl

A 17-year-old girl with unilateral congenital glaucoma who had undergone trabeculectomy and peripheral iridectomy in infancy developed apparent exfoliation syndrome (XFS) in the eye that underwent the surgical procedures. A conjunctival biopsy was performed and the specimen was fixed in 2.5% glutaraldehyde, embedded in epoxy resin (Epon-Araldite, Electron Microscopy Sciences, Fort Washington, Pa), and processed for routine electron microscopy and immunostaining for elastin. Results of ultrastructural study showed scattered fibrillar aggregates compatible with those of XFS in an older adult, differing chiefly in sparsity of granular interfibrillar matrix. The XFS fibers were closely associated with elastic fibers and microfibrils. Elastosis of the actinic-aging type was somewhat greater than expected for age. To our knowledge, this is the youngest patient described with characteristic ocular findings of XFS to date, supporting others who have suggested an association between iris surgery in youth and early onset XFS. Electron microscopy was essential in ruling out the possibility of a clinically similar entity caused by ultrastructurally different material.

Clinical presentation and initial treatment patterns in patients with exfoliation glaucoma versus primary open-angle glaucoma

BACKGROUND AND OBJECTIVE

The presentation and initial response to treatment of consecutive patients with exfoliation glaucoma (PXE) and primary open-angle glaucoma (POAG) were evaluated prospectively.

PATIENTS AND METHODS

Forty-six consecutive newly diagnosed patients with POAG and PXE were included in a prospective study that evaluated the initial clinical course and treatment results. The two groups were age- and race-matched.

RESULTS

This study found no difference in optic disc parameters at presentation between patients with POAG (n = 22) and those with PXE (n = 24) (P > .05). However, the presenting mean defect was significantly worse in patients with PXE versus those with POAG (P = .0038), although the loss variance was similar (P > .90). The mean presenting intraocular pressure (IOP) for patients with PXE (32.0 +/- 5.2 mm Hg) was greater than that for patients with POAG (27.1 +/- 4.4 mm Hg) (P= .0025). Additionally, patients with PXE required more treatment steps to control IOP (P = .005). Thirteen of 24 patients with PXE versus 3 of 22 patients with POAG (P = .016) required either laser or conventional surgical techniques to reduce IOP.

CONCLUSION

This study shows that patients with PXE have greater visual field loss and have more difficulty gaining control of IOP on presentation than patients with POAG.

Diurnal intraocular pressure in untreated exfoliation and primary open-angle glaucoma

OBJECTIVE

To describe and compare the diurnal intraocular pressure (IOP) variation in patients with exfoliation glaucoma (EXG) and primary open-angle glaucoma (POAG).

PATIENTS AND DESIGN

We prospectively investigated consecutive Greek patients with newly diagnosed untreated EXG and POAG. All patients were admitted to our ophthalmology department for 24-hour IOP measurements according to a standard protocol. After matching for age, we compared 40 pairs of patients with these 2 glaucomas.

RESULTS

Patients with EXG showed a significantly higher mean range of IOP (13.5 vs 8.5 mm Hg for POAG; unpaired t test, P < .001), higher maximum IOP (mean, 38.2 vs 26.9 mm Hg for POAG; unpaired t test, P < .001), and higher minimum IOP (mean, 24.7 vs 18.4 mm Hg for POAG; unpaired t test, P < .001) Patients with EXG more often demonstrated an IOP range higher than 15 mm Hg (35% vs only 7.5% for POAG). Importantly, in 45% of patients with EXG and 22.5% of patients with POAG, the peak level of IOP was found outside office hours. There was no significant difference in visual function (visual acuity, cupping, visual field) at diagnosis between the 2 glaucoma groups.

CONCLUSION

Significant fluctuation in the diurnal curve of the IOP distinguishes EXG from POAG and may be an important factor in predicting any subsequent poor response to medical therapy.

Frequency of exfoliation syndrome in Greek cataract patients

The frequency of exfoliation syndrome (EXS) was investigated in a group of Greek patients undergoing extracapsular cataract surgery. Five hundred and nine (509) consecutive cataract patients without any other manifest ocular abnormality were prospectively examined for the presence of EXS. Patients were clinically divided into 3 groups: group I (EXS group) consisted of patients in whom exfoliation material deposition could be seen; Group II (possible EXS group) comprised patients who demonstrated a number of pigmentary signs and group III (normal subjects) comprised patients with senile cataract and no sign of EXS. EXS was found in 140 (28%) of our patients, possible EXS in 119 (23%) and the rest (49%) had no evidence of EXS. Patients with EXS were older (mean age 73.8) when compared to the possible EXS group (70 years) and the control group (64.7 years). The IOP was significantly higher in patients with EXS (mean 15.5 mmHg versus 14.3 mmHg in the other two groups). Blue irides were significantly more common in patients with EXS (19%) than in the possible EXS group (14%) and the controls (4%). EXS is common in Greek cataract patients and this study has identified a large group of patients who may be at an early stage of development of the condition. EXS may predispose to the development of cataract in Greek patients.

Possible role of transferrin in exfoliation syndrome

Protein concentration was measured in 30 exfoliation syndrome samples and 22 age matched controls. Exfoliation samples contained significantly more protein than controls. We also analyzed by SDS gel electrophoresis 32 aqueous samples, 12 with exfoliation syndrome and 20 age matched controls. A novel finding in all samples was a double band with 77 kDa and 78 kDa. These bands probably represent transferrin isoforms, with different carbohydrate side chains. Exfoliation samples contained a lower amount of the 77 kDa band in comparison to the amount of the 78 kDa band. The lower relative concentration of this transferrin isoform in the exfoliation syndrome samples may be indicative of its possible involvement in the disorder. A different oligosaccharide side chain in combination with a relatively high protein concentration may lead to sedimentation of this molecule. On the other hand, laminin, a glycoprotein detected previously in exfoliation material, contains similar oligosaccharide side chains with transferrin. Thus the oligosaccharide side chains of both proteins may be influenced by the same factors.

Simple iris coloboma in a Greek family

We report the presence of simple iris coloboma in 4 out of 5 female members comprising four generations of a Greek family. A varied degree of simple iris coloboma (i.e. not associated with a choroidal coloboma) was present in one eye of the maternal grandmother, mother, daughter and one out of 2 granddaughters of this family. The iris colobomata were associated with congenital lens opacities in 2 out of 4 of the females, macular degenerative changes in 2 cases and ocular hypertension in one case. The pathogenesis, heredity and associations of simple iris colobomata is discussed.

Immunogold study of non-collagenous matrix components in normal and exfoliative iris

The present investigation was undertaken to determine if some of the components of exfoliation material in iris tissue were unique to exfoliation or were part of normal iris architecture. Eleven normal iris specimens and 10 exfoliative iris specimens were processed for cryoultramicrotomy and London resin white embedding. Immunogold electron microscopy was used to investigate the fine structural distribution of amyloid P component, elastin, entactin, fibronectin, gp115, and vitronectin in normal iris and their association with exfoliation material. Exfoliation material was positive for amyloid P component and possibly gp115, neither of which were present in normal iris tissue. Elastin and fibronectin were present in the normal iris stroma but were not associated with exfoliation material. The distribution of amyloid P component in the vessel lumen and wall led to the conclusion that amyloid P is a serum contaminant. The presence of gp115 in exfoliation material represents the synthesis of a component novel to the iris vascular cell synthetic repertoire.

Collagens in the aged human macula

Immunogold cytochemistry was used to investigate the fine structural distribution of collagen types I-VI in Bruch's membrane and choroid of the aged human macula. Macular tissue was obtained from ten eyes, and processed for cryoultramicrotomy and London Resin white embedding. Striated collagen fibrils within the inner and outer collagenous layers were found to contain collagen types I, III and V. In addition, type V collagen was also present in the basement membrane of the choriocapillaris. Gross thickening of the choriocapillaris basement membrane was attributed to the deposition of type IV collagen. However, type IV collagen appeared to be absent from the basement membrane of the retinal pigment epithelium. The interesting location of type VI collagen on the choroidal side of the choriocapillaris suggested that its function is to anchor the choriocapillaris onto the choroid. The collagens studied were absent from fibrous banded material, long-spacing collagen, the elastic layer and amorphous granular material. It was concluded that, of the collagen types studied, only the deposition of type IV collagen contributes to the age-related thickening of Bruch's membrane.

Co-existence of exfoliation syndrome, previous iris surgery, and heterochromia

A case is described where exfoliation syndrome developed in a relatively young patient with heterochromia. The patient had previously undergone large radial iridotomies as part of penetrating keratoplasty procedures. This case illustrates an association between iris surgery and early manifestation of exfoliation syndrome.

Morphology of iris vasculopathy in exfoliation glaucoma

Iris tissue obtained from 26 consecutive patients operated upon for exfoliation glaucoma and control iris tissue from 26 age-matched subjects operated upon for primary open angle glaucoma was used to investigate the iris vasculopathy associated with exfoliation glaucoma. By light microscopy exfoliation material was discerned by increased density of the perivascular matrix in affected vessels. By transmission electron microscopy exfoliation vasculopathy was divided into 4 grades. Grade I was characterized by focal accumulation of exfoliation material without evidence of cellular degeneration. In grade II, exfoliation material accumulation was accompanied by degeneration of vascular supporting cells; endothelial cells were unaffected. In grade III, endothelial cells exhibited degenerative changes and in grade IV, exfoliation material occupied an acellular vascular wall (ghost vessel). It is suggested that in iris vessels the synthesis of exfoliation material can be attributed primarily to the vascular supporting cells.

Prevalence, diagnostic features, and response to trabeculectomy in exfoliation glaucoma

BACKGROUND

The "true" prevalence and clinical attributes of exfoliation glaucoma remain controversial. The authors studied these characteristics in glaucoma patients requiring trabeculectomy.

METHODS

One hundred consecutive patients undergoing trabeculectomy for open-angle glaucoma were investigated by clinical examination (biomicroscopy and gonioscopy) and classified into three categories: exfoliation glaucoma, possible exfoliation glaucoma, and primary open-angle glaucoma (POAG). A definitive diagnosis of exfoliation glaucoma was provided by pathologic examination of iris tissue.

RESULTS

All 22 patients with clinical evidence of exfoliation glaucoma and 4 of 18 patients with possible exfoliation glaucoma on clinical examination had ultrastructural evidence of exfoliation material. The prevalence of exfoliation glaucoma, therefore, was 26%. The clinical examination for the diagnosis of exfoliation glaucoma had an 85% sensitivity rate and a 100% specificity rate. In comparison with POAG, patients with exfoliation glaucoma had higher untreated intraocular pressure (IOP), higher IOP with medical therapy, and shorter duration of medical therapy. They were more often operated on for unacceptably high IOP. Exfoliation glaucoma patients exhibited significantly lower IOP after surgery.

CONCLUSION

Exfoliation glaucoma is common in patients requiring trabeculectomy for open-angle glaucoma. This condition differs from POAG by a poorer response to medical therapy and a better response to trabeculectomy.

[Exfoliation syndrome and open angle glaucoma]

Terms such as "primary open angle glaucoma" and "chronic open angle glaucoma" are used to include both exfoliation glaucoma and POAG and some studies fail even to consider the disorder (11). This approach, is inappropriate since exfoliation glaucoma and POAG are different entities. Clinical and morphological evidence supports the view that exfoliation glaucoma is a true secondary open-angle glaucoma. The balance of ultrastructural evidence is in favour of exfoliation glaucoma developing due to an accumulation of exfoliation material and pigment within the outflow system of the affected eye. Clinically, exfoliation glaucoma has a number of specific attributes which distinguish it from POAG. It has a worse prognosis than POAG for medical therapy and ALT, but this may not apply in the case of prompt surgical intervention.

Collagens in the aged human macular sclera

Scleral tissue from the region of the human macula was studied by the immunogold labeling technique (cryoultramicrotomy and LR white resin embedding) in an attempt to identify the fine structural distribution of collagen types I-VI. Labeling of the striated collagen fibrils suggested colocalisation of collagen types I, III and V with type V occurring at the fibril surface. Both types V and VI collagen were localised to filamentous strands in the interfibrillar matrix. Collagen types II and IV were absent from the scleral stroma.

Type IV collagen and laminin in Bruch's membrane and basal linear deposit in the human macula

Tissue obtained from the macula in 10 human eyes (53-77 years) was used for an investigation into the extracellular matrices of the retinal pigment epithelium (RPE), Bruch's membrane, and the choriocapillaris. The ultrastructural distribution of type IV collagen and laminin was documented using immunogold labelling. Labelling for type IV collagen was strongly positive in all the specimens in the basement membranes of the choriocapillaris but not that of the RPE where labelling was either weak or absent. Laminin was localised to deposits of granular material in Bruch's membrane but was absent from the basement membrane of the RPE and the choriocapillaris. Basal linear deposit, observed in three cases, demonstrated labelling for laminin but not for type IV collagen. The series was too small for correlation of these morphological changes with age.

Extracellular matrix in aged human ciliary body: an immunoelectron microscope study

Tissue from nine human eyes (ages 52-78 yr) was used to investigate the fine structural distribution of collagens I-VI and laminin in the ciliary body using the immunogold antibody labeling technique. The anterior segments of the specimens were normal, and the eyes were removed in treatment of choroidal melanoma. The basement membranes of the ciliary epithelium contained collagens I, III, and IV. Laminin was in greater concentration in the outer part of the nonpigmented epithelial basement membrane, and the distribution suggested a washout effect. The zonular apparatus labeled intensely with laminin. In contrast, laminin was not present in the basement membrane of the myocytes in the ciliary body. These cells were sheathed in a basement membrane that contained types I, III, and IV collagen. Plaque-like structures of slightly different morphology (a, filamentous; b, granular; c, amorphous) were found in the tendinous insertions, and subtypes a and b were strongly labeled with laminin. The basement membranes of the vessels contained types I and IV collagen, but laminin labeling was inconclusive. The major finding was that the lamina densa in the basement membranes of various sites labeled for collagens I, III, and IV. Striated collagen fibrils in the stroma were labeled for types I and III. Collagen subtypes V and VI were not identified in significant quantity in any of the regions examined.

Modification of trabeculectomy to avoid postoperative hyphaema. The 'guarded anterior fistula' operation

The effect of varying the position of a trabeculectomy fistula on the rate of postoperative hyphaema was studied in a prospective randomised trial. One eye of each of 78 consecutive patients with primary open angle glaucoma and exfoliation glaucoma was allocated to one of two groups. In group A the fistula was fashioned anterior to the scleral spur, entirely in corneal tissue. In group B the fistula included cornea and sclera with trabecular meshwork and scleral spur. Seven out of 39 eyes (18%) in group A developed a postoperative hyphaema with detectable blood level, compared with 22 out of 39 eyes (56%) for group B (p less than 0.001). In addition, the severity of the bleeding was greater in group B, and the three cases of recurrent bleeding were all in this group. Group B patients remained in hospital for an average of 3.9 days, which was significantly longer (p = 0.004) than the average of 2.9 days for group A. This difference was related to the frequency and severity of the hyphaema. The type of dissection or the occurrence of hyphaema did not influence the intraocular pressure at 4 months after surgery.

An immunoelectron microscope study of the aged human lens capsule

The distribution of types I-IV collagen and laminin was studied in seven aged human lens capsules using the immunogold EM technique on LR White embedded tissue. Samples were taken from the anterior, equatorial and posterior regions. Labelling for type II collagen was not observed. Type IV collagen was evenly distributed throughout the thickness of the capsule but was absent from the zonules. However, an unexpected finding was strong labelling for types I and III collagen, again evenly distributed throughout the capsule. The presence of type III collagen makes the lens capsule unique among ocular basement membranes. Laminin was present in linear densities, zonular lamellae and zonular fibres, suggesting that linear densities are an integral part of the zonular apparatus.

Iris vasculopathy in exfoliation syndrome. An immunocytochemical study

Samples of control iris tissue obtained from seven enucleated eyes and nine exfoliative iridectomy specimens were prepared for an immunocytochemical study of the matrix in the walls of iris vessels. The distribution of collagen types I, IV and laminin was studied in normal and exfoliative vessels. Laminin was an integral component of exfoliation material and was present mainly in the matrix of the outer surface of normal vascular cohort cells. The laminin content in the latter location was reduced in vessels in which exfoliation aggregates were not visible. Collagen type IV was absent from exfoliation material. While type I was present in the deposits, it was considered to represent a residue of native normal tissue. Exfoliation deposits appeared to stimulate the synthesis of collagen types I and IV at an early stage of the disease.

Gonioscopic findings in Greek patients with exfoliation glaucoma

A prospective gonioscopic evaluation was carried out upon a cohort of Greek patients who had undergone trabeculectomy for open-angle glaucoma. Sixty-five patients were found to show clinical evidence of exfoliation glaucoma (EXG), whilst nine patients were deemed to have primary open angle glaucoma (POAG). The gonioscopic features of these eyes and of 43 non-operated eyes from the same patients with either exfoliation syndrome (EXS) or EXG are presented. The median degree of angle pigmentation was significantly higher in the operated eyes with EXG when compared with the POAG cases. In the operated eyes, deposition of exfoliation was found on the ciliary processes in 82% of cases and on the zonules in 52%.

Immunogold ultrastructural localization of collagens in the aged human outflow system

Immunogold labeling was applied at the ultrastructural level to the identification of collagen types I, II, III, V, and VI in the human trabecular meshwork obtained from 11 surgically enucleated globes. Both London resin white embedding and cryoultramicrotomy were used, and for types V and VI, the latter provided more sensitive localization. Type II collagen was not identified. Types I and III were localized to the striated collagen fibrils of the trabecular core, the basement membrane of the trabecular beams, and loose aggregates in the juxtacanalicular tissue. Types V and VI formed a fine network around the striated fibrils in the trabecular cores and linkage strands to the basement membranes. The outer wall of Schlemm's canal contained collagens I, III, V, and VI. Long-spacing collagen and elastin-like material did not label with any of the antibodies used in this study.

Immunogold fine structural localization of extracellular matrix components in aged human cornea. II. Collagen types V and VI

Using immunogold immunocytochemical techniques we studied the distribution of collagen types V and VI in corneal tissue from seven enucleated human eyes (age range, 63-78 years). Results obtained by cryoultramicrotomy were marginally more intense than those obtained using London Resin white (LR white) embedding. Type V collagen was present in the striated collagen fibrils in Bowman's layer, in the stroma and in a thin, non-banded anterior zone of Descemet's membrane. Our results suggest that types I, III and V collagen co-distribute in striated collagen fibrils. By contrast, type VI collagen was located in fine filaments in the interfibrillar matrix of the stroma, in Bowman's layer and in the anchoring plaques of the sub-epithelial basement-membrane complex. This implies an importance in epithelial adhesion which was previously unsuspected. Keratocyte bodies were electron-dense, amorphous extracellular deposits of matrix-like material, and these were labelled with types III, V and VI collagen antibodies. Long-spacing collagen was observed in the corneal stroma, and this deposit did not contain any of the collagen types studied.

Immunogold fine structural localization of extracellular matrix components in aged human cornea. I. Types I-IV collagen and laminin

Using the immunogold technique combined with cryoultramicrotomy and London Resin white (LR white) embedding, we studied the fine structural distribution of types I-IV collagen and laminin in corneal tissue from seven enucleated human eyes (age range, 63-78 years). Type II collagen was not identified in any corneal layer. Type I and type III collagen were distributed in a similar fashion in striated collagen fibrils in Bowman's layer and in the stroma. Type IV collagen was located only in the posterior non-banded region of Descemet's membrane. Laminin was identified in subepithelial anchoring plaques and the sub-endothelial region of Descemet's membrane in accordance with its recognized adhesive function.

Immunogold localization of type IV collagen and laminin in the aging human outflow system

Tissue from the outflow system of six surgically enucleated aged eyes was used for an ultrastructural immunocytochemical study of the distribution of laminin and type IV collagen. The immunogold technique provided precise localization of laminin beneath lining endothelial cells of the inner wall of Schlemm's canal. Laminin labelling was absent in the trabecular beams. Type IV collagen was found in the basement membranes of the trabecular beams and in fine filamentous basement membrane material in the cribriform layer. Electron dense plaques in the cribriform layer labelled positively for laminin in the outer coarse fibrillar zone but not in the electron dense core. Long-spacing collagen was negative for type IV collagen.

Immunogold localisation of laminin in normal and exfoliative iris

Immunoelectron microscopic studies of exfoliative iris tissue (seven specimens) revealed the presence of laminin in the fibrillar component of exfoliation material. The immunogold label was uniformly distributed on the exfoliation fibres. Deposition of laminin labelled exfoliation material in the dilator muscle was a noteworthy feature, as was an apparent depletion of laminin in the basement membranes of ostensibly unaffected vessels. In control iris tissue (five enucleated eyes) laminin was identified in the basement membrane round vascular contractile cells, but not beneath the endothelium.

Ultrastructural distribution of collagen types I-VI in aging human retinal vessels

Retinal vessels from freshly enucleated human eyes were classified into three stages of the hyalinisation process. The distribution of collagen types I-VI within the vessel walls was studied ultrastructurally by immunogold labelling combined with the tissue preparation techniques of cryoultramicrotomy and London resin white embedding. Collagen types I, III, IV, V, and VI were found in large vessels, types I, IV, and V plus small amounts of III and VI in small vessels, and types I, IV, and V in capillaries. Hyalinised vessel walls consisted mainly of types I, IV, and VI collagen.

Immunocytochemical localisation of collagens (I-V) in the human iris

In this study we investigated the distribution of collagen types I-V in the human iris at the fine-structural level using cryoultramicrotomy and London Resin White plastic embedding. Collagen type I was shown to be present in the basement membrane of iris vessels, in contrast to type III, which was absent; both types I and III were present in the iris stroma. Collagen type IV was a major component of basement membranes of vascular cells, myoepithelial cells, fibroblasts and epithelial cells. Types II and V were absent. Both cryo and plastic embedding techniques produced closely comparable results.

Pseudoexfoliation glaucoma in Greece

Pseudoexfoliation glaucoma is commonly seen in Greece, however there is little data concerning the prevalence and characteristics of this disorder. Patients undergoing trabeculectomy for open angle glaucoma were investigated both by the appraisal of the case notes and by re-examination. The prevalence of pseudoexfoliation glaucoma in this population was found to be 87.8%. The characteristics of this disease process in the population studied are discussed. These findings indicate that pseudoexfoliation is a major contributor to severe glaucoma in the population of Northern Greece.