Cataract Surgery and Possible Complications in Patients with Pseudoexfoliation Syndrome

Materials and Methods: Cases of 225 eyes (80 eyes with pseudoexfoliation and 145 eyes without pseudoexfoliation as the control group) that underwent phacoemulsification cataract surgery and IOL implantation at the Silifke State Hospital Ophthalmology Clinic between April 2011 and April 2013 were analysed retrospectively. Patients with a history of previous ocular surgeries, ocular trauma, uveitis, glaucoma or corneal pathology were not included in the study. All cataract procedures were performed by the same surgeon. Patients’ age, gender, anterior segment and fundus findings in both eyes, presence of pseudoexfoliative material, preand postoperative day 1 intraocular pressure (IOP) and surgery notes were evaluated.


Introduction
Pseudoexfoliation syndrome (PEX) is a condition characterized by the secretion of a grey-white, fibrogranular substance in the anterior segment.The source of this substance is multifocal and is believed to appear secondary to abnormal basal membrane constituents produced by aging epithelial cells [1].PEX is diagnosed clinically by anterior segment examination, and is defined as the presence of grey-white fibrogranular pseudoexfoliation material on the anterior capsule of the lens and edges of the pupil [2,3].The prevalence of PEX varies by population; however, PEX frequency increases with age and it is believed that an extremely significant relationship exists between age-related cataractous lens changes and PEX [4].
In eyes with PEX, it has been reported that degenerative changes in the iris stroma and muscle layer may interfere with sufficient pupil dilation [5].In eyes with pseudoexfoliation, the lens zonules can become detached from the ciliary body and lens by mechanical forces or enzymatic zonulolysis.Clinically, this can lead to iridophacodonesis and spontaneous lens subluxation or dislocation [6].These structural changes make cataract surgery more difficult and increase the incidence of intraoperative complications [7,8].
The aim of this retrospective study was to evaluate the demographic characteristics and intraoperative complications of cataract surgery in PEX patients.

Materials and Methods
Cases of 225 eyes (80 eyes with pseudoexfoliation and 145 eyes without pseudoexfoliation as the control group) that underwent phacoemulsification cataract surgery and IOL implantation at the Silifke State Hospital Ophthalmology Clinic between April 2011 and April 2013 were analysed retrospectively.All patients were given detailed information about their diagnosis and surgical procedures to be applied, and written informed consent was obtained.
Patients with previous ocular surgery or trauma, uveitis, glaucoma, IOP≥21 mmhg or corneal pathology were excluded from the study.All cataract surgeries were per-formed using quick chop technique by the same surgeon.Patients' age, gender, anterior segment and fundus findings in both eyes, presence of pseudoexfoliative material, preoperative and postoperative day 1 IOP, and surgical notes were evaluated.Intraocular pressure was measured by applanation tonometry (Haag-Streit, Switzerland) in all patients.

Statistical analysis
Statistical Package for the Social Sciences 15 for Windows, a statistical software application (SPSS Inc.; Chicago, IL, USA) was used for statistical analysis.Comparison of categorical variables was done with chi-square and Fisher exact tests.Independent t-test and paired t-test were used for mean comparisons.P values less than 0.05 were accepted as statistically significant.

Results
There were 51 (34.7%) males and 29 (38.6%)females among the PEX cataract patients, and 98 (65.3%) male and 47 (61.8%) female controls.The incidence of pseudoexfoliation was similar in women (38.2%) and men (34.7%) (p=0.660).There was no statistically significant effect of gender on pseudoexfoliation frequency (Table 1).The mean age was 74.64±6.8 in the PEX group and 68.95±7.5 in the control group.Mean age was significantly higher in the PEX group compared to controls (p<0.001,Table 2).
Poor pupil dilation was observed intraoperatively in 60 (75%) of the patients with pseudoexfoliation and 17 (11.7%) of the control patients.Frequency of poor intraoperative pupillary dilation was significantly higher in the PEX group compared to controls (p<0.001,Table 3).Intraoperative posterior capsule rupture occurred in 10 (12.5%)PEX patients and 5 (3.4%) controls.The incidence of intraoperative posterior capsule rupture was statistically significantly higher in the PEX group compared to the control group (p=0.012,Table 4).Intraoperative vitreous loss occurred in 7 (8.8%)PEX patients and 5 (3.4%) controls.Despite the fact that more PEX patients developing vitreous loss than controls, the difference was statistically insignificant (p=0.090,Table 5).The difference between ''posterior capsular rupture'' and ''vitreous loss'' should be identified.

Discussion
The incidence of PEX varies by population, ethnic group and age.However, studies consistently show that the frequency of PEX increases with age [9][10][11][12].In a study conducted in the Çukurova Region of Turkey, Yalaz et al. reported a PEX frequency of 11.2% in individuals over 60 years old [12].In their epidemiological study, Elibol et al. ( 13) found a PEX incidence of 13.7%.Consistent with these findings, an increase in the frequency of PEX with age was observed in the current study.The mean age of the PEX patient group was significantly higher than that of the control group (p<0.001).
There are reports in the literature of a significant relationship between PEX and cataract development; furthermore, certain challenges of cataract surgery in the presence of PEX and increased risk of complications have been reported [8,14].Complications during cataract surgery occur at a higher rate in eyes with pseudoexfoliation than in standard cataract cases due to increased frequency of glaucoma and poor pupillary dilation.There is also a higher risk of zonular dialysis, capsule rupture, vitreous loss and postoperative IOL decentralization [14].It is considerably more difficult to achieve  (8,15,16).Iris haemorrhage, corneal endothelial damage, lens dislocation, vitreous loss, posterior capsule rupture and sphincter rupture occur more frequently in eyes with insufficient intraoperative pupillary dilation during cataract extraction [15][16][17][18].Drolsum et al. [19] also reported a higher rate of posterior capsule rupture without vitreous loss in PEX eyes compared to controls, although there was no difference in the incidence of vitreous loss.There are many studies in the literature about intraoperative complications of cataract surgery in PEX patients.In a study of phacoemulsification in PEX eyes conducted by Drolsum et al. [20], intraoperative complications occurred in 9.6% of the eyes with pseudoexfoliation, compared to 3.7% of the eyes without pseudoexfoliation.Lumme et al. [7] found significantly higher rates of intraoperative complications including zonular rupture, posterior capsule rupture, and vitreous loss (14.8%, 10.2%, and 7.4%, respectively) during cataract surgery on eyes with PEX, and suggested that zonular and posterior capsule rupture are important risk factors for vitreous loss.Scrolli et al. [16] also found higher intraoperative incidences of zonular dialysis, posterior capsule rupture and vitreous loss in PEX patients undergoing phacoemulsification than in patients without pseudoexfoliation.Avramides et al. (21) found that 61.9% of the patients with PEX had a pupil diameter of less than 5 mm, and the incidence of intraoperative complications in these patients was as follows: zonulolysis, 13.09%; posterior capsule tear, 10.71%; and vitreous loss, 7.14% [21].In the current study, poor pupillary dilation occurred in 75% of the patients in PEX group, compared to 11.7% in the non-PEX group.Intraoperative posterior capsule rupture occurred in 12.5% of PEX patients and 3.4% of the patients without pseudoexfoliation.Vitreous loss was observed in 8.8% of the patients in PEX group and 3.4% of non-PEX group; despite the fact that more patients in the PEX group had vitreous loss, the intergroup difference was not statistically significant.However, the rates of poor pupillary dilation and posterior capsule rupture were significantly higher in the PEX group when compared to the non-PEX controls.Our results support the observation that pseudoexfoliation increases the incidence of poor pupillary dilation and is a factor that increases the risk of complications such as posterior capsule rupture during cataract surgery.
Cataract patients considering surgery should be evaluated preoperatively for pseudoexfoliation.Surgeons should be aware of the possibility of poor pupillary dilation and the complications that can arise in patients with PEX during cataract surgery.Caution should be taken during every stage of surgery to avoid these complications, and surgeons should be knowledgeable and skilled in complication management should they occur.

Table 1 . Relationship between gender and PEX
Erkayhan and Doğan.Cataract Surgery in Patients with Pseudoexfoliation Syndrome Eurasian J Med 2016

Table 2 . Relationship between age and PEX
PEX: pseudoexfoliation syndrome; SD: standard deviation

Table 3 . A comparison of PEX and poor pupillary dilation
Erkayhan and Doğan.Cataract Surgery in Patients with Pseudoexfoliation SyndromeEurasian J Med 2016