Klinična študija / Clinical study VVpliv opciriEicije Icaatairakte na debelino mrežnice Influence of cataract siirgi^ry on retinal thickness Avtor / Author Ustanova / Institute Katarina Šiško2, Nina Knez2, Dušica Pahor12 1Univerzitetni klinični center Maribor, Oddelek za oftalmologijo, Maribor, Slovenija; 2Univerza v Mariboru, Medicinska fakulteta, Maribor, Slovenija University Clinical Centre Maribor, Department of Ophthalmology, Maribor, Slovenia; 2University of Maribor, Faculty of Medicine, Maribor, Slovenia Ključne besede: operacija katarakte, optična koherentna tomografija (OCT), debelina mrežnice, volumen mrežnice, RNFL Key words: cataract surgery, optical coherence tomography (OCT), retinal thickness, retinal volume, RNFL Članek prispel / Received 14.10.2010 Članek sprejet / Accepted 03.11.2010 Naslov za dopisovanje / Correspondence Prof. dr. Dušica Pahor, dr.med. Univerzitetni klinični center Maribor, Oddelek za oftalmologijo, Ljubljanska 5, Sl-2000 Maribor, Slovenija Telefon +386 23211630 Fax +386 23312393 E-pošta: d.pahor@ukc-mb.si Izvleček Namen: Namen raziskave je oceniti morebitni vpliv operacije katarakte na debelino mrežnice makule in sloja mre-žničnih živčnih vlaken (RNFL), merjenih v različnih časovnih intervalih v obdobju enega meseca po operaciji. Metode Vprospektivno študijo je bilo vključenih 27 bolnikov (27 oči), ki so bili naročeni na ambulantni poseg operacije katarakte s fakoemulzifikacijo in vstavitvijo lOL. Za meritve debeline makule, volumna makule in debeline RNFL operiranih oči smo uporabili optično koherentno tomografijo (OCT). Meritve smo izvajali pred operacijo ter 1, 14 in 30 dni po operaciji katarakte. Meritve kontralateralnega zdravega očesa so predstavljale kontrolno skupino (19 bolnikov, 19 oči). Rezultati Mesec dni po operaciji se je debelina statistično značilno pove- Abstract Purpose: We evaluated the potential influence of cataract surgery on macular thickness and on the thickness of the retinal nerve fibre layer (RNFL) at different time intervals within 1 month after surgery. Methods: This prospective study involved 27 patients (27 eyes) scheduled for ambulatory cataract surgery with phacoemulsification and intraocular lens implantation. Optical coherence tomography was used to measure macular thickness, macular volume and RNFL thickness on operated eyes on the day before surgery and 1, 14 and 30 days after surgery. Contralateral non-operated eyes served as a control group (19 patients, 19 eyes). Results: One month after surgery, 75% of the macula showed a significant increase in thickness (p<0.05). čala na treh četrtinah celotne površine makule (p < 0,05). Meritve RNFL so pokazale, da se povprečne vrednosti pri operirani skupini v primerjavi z vrednostmi pred operacijo ne povečajo (p > 0,05). Zaključek: Rezultati so potrdili vpliv operacije katarakte na debelino makule v obdobju enega meseca po operaciji. RNFL measurements revealed that mean values in the operated group did not increase compared with preoperative values (p>0.05). Conclusion: These results confirmed the influence of uncomplicated cataract surgery on macular thickening 1 month after surgery. INTRODUCTION MATERIAL AND METHODS Every intraocular procedure (including cataract surgery) causes an immune-system response. This is the result of a biochemical cascade of events ('inflammatory response') or damage to the blood vessels and non-pigmented ciliary epithelium of the iris. In the case of intraoperative complications such as rupture of the posterior lens capsule or vitreous loss, cystoid macular oedema can occur after cataract surgery (1-3). This prospective study involved 42 patients who underwent cataract surgery in one eye at the Department of Ophthalmology in the University Clinical Centre Maribor between June and August 2010. The healthy contralateral eyes served as controls. Exclusion criteria were: age-related macular degeneration, glaucoma, diabetic reti-nopathy, prior intraocular surgery, ocular trauma, uveitis, and other conditions that could cause macular oedema. Advanced surgical techniques and pharmacological therapy have significantly decreased the biological response and consequently complications after cataract surgery. However, uneventful cataract surgery can lead to minor changes to the retina, such as sub-clinical cystoid macular oedema and retinal leakage as detected by angiography. The long-term consequences of these findings are not known (2-7). Optical coherence tomography (OCT) is a non-contact, non-invasive and widely used tool for the diagnosis of retinal changes. It is designed to analyse retinal thickness and to reveal macular disease. The use of OCT in the postoperative period enables the detection of sub-clinical changes in macular thickness. Despite numerous studies, the influence of cataract surgery on macular thickness and the retinal nerve fibre layer (RNFL) has not yielded consistent results (2,3,8-10). Surgeries were carried out under topical anaesthesia in all cases using a standard technique by experienced surgeons. Each patient underwent standard phaco-emulsification surgery followed by in-the-bag intraocular lens (IOL) implantation. The surgical technique was the same in all eyes and intraoperative complications were not observed. Fifteen patients were lost from follow-up due to non-compliance or they missed their planned examination. Patients who attended at least two of the follow-up measurements were included in the statistic analysis. This resulted in a reduction in the number of eyes measured before surgery to 27 eyes (and 19 eyes in control group) measured 2 weeks after surgery. All patients were informed about the procedure and gave their verbal consent. The goals of the present study were to: (i) evaluate the potential influence of cataract surgery on macular thickness at different times within 1 month after surgery; and (ii) measure the thickness of the RNFL after surgery at the same time intervals. Preoperative bilateral biometric data such as axial length, keratometry and anterior chamber depth were measured with an lOL Master Optical Biometer (Zeiss lOL Master; Carl Zeiss Meditec Ophthalmic Systems Incorporated, Dublin, CA, USA). OCT (Zeiss Stratus OCT version 4.0.1), Carl Zeiss Meditec Ophthalmic Systems) was used for measurements of retinal thickness, retinal volume and retinal nerve fibre layer (RNFL) thickness. OCT is based on the principle of Michelson interferom-etry. Light passing through the eye is reflected by structures in different layers of retinal tissue. Moving the source of light over the retinal surface produces a two-dimensional cross-sectional image that resembles a histology section. The instrument electronically detects, collects, processes and stores the echo delay patterns from the retina. It displays the tomograms in real time using a false colour scale that represents the degree of light backscattering from tissues at different depths in the retina. The system stores the scans, which can be selected for later analyses (11-16). OCT examinations were done on both eyes with the contralateral eye serving as control. Measurements were undertaken in the foveal and perifoveal area on the preoperative day (T) and on postoperative days 1 (T+1), 14 (T+14) and 30 (T+30). A 'Fast Macular Thickness Map' scan protocol was used to obtain six macular scans that were 6 mm in length and centred on the fovea equally and set 30° apart. A 'Fast RNFL Thickness' scan protocol was used to measure RNFL thickness around the macula. Thickness values of the following macular regions were analysed: foveal minimum thickness (FM), fovea, temporal inner macula (TIM), superior inner macula (SIM), nasal inner macula (NIM), inferior inner macula (IIM), temporal outer macula (TOM), superior outer macula (SOM), nasal outer macula (NOM), and inferior outer macula (IOM). Statistical analyses were carried out using with SPSS for Windows 17.0 (SPSS Incorporated, Chicago, IL, USA). Preoperative and postoperative measurements were compared using the paired samples t-test. Potential differences between data from the test and control group were evaluated by the independent Student's t-test. P<0.05 was considered significant. RESULTS The data analysis included the patients who took part in at least three measurements: the day before surgery, the day after surgery, 14 days after surgery and/or 30 days after surgery. This encompassed 27 patients (27 eyes) who underwent cataract surgery ('operated group') and a control group (which comprised the 19 contralateral healthy eyes of 19 patients). Participants were without any known macular disease. The mean ± SD age in the operated group was 69.07±8.74 years and was 68.89±8.86 in the control group. There was no significant difference in mean age between the two groups. Statistically significant differences between the operated group and the control group were not observed with respect to: the mean ± SD anterior chamber depth; axial length of the eye; and the keratometric values in horizontal and vertical axis measured in dioptres and millimetres (Table 1). Each OCT measurement provided the data for the thickness and volume of the macula. In this way, the values of FM, the thickness and volume of the fovea, average thickness and volume for each of the eight parafoveal regions (Figure 1) and RNFL were obtained. Comparison between the operated group and the control group at the same time intervals (before surgery, 1 day after surgery, 14 days after surgery, and 30 days after surgery) showed a statistically significant difference 14 days after surgery in the nasal quarter of the macula— NIM and NOM (p<0.05)—and 30 days after surgery in the whole parafoveal region (p<0.05) (Table 2). When comparing macular thickness on the day before surgery (T) with measurements one day after surgery (T+1), 14 days after surgery (T+14) and 30 days after surgery (T+30) in operated and control groups, there was a significant difference in the operated group in the fovea and NIM between T and T+14 and in all areas of the parafoveal region except the superior quarter between T and T+30. In the control group, a significant difference was found in the area TIM Table 1: Characteristics of the patient population Opeiated gioup (N=27) Contiol group (N=I9) Mean SD Mean SD Age (years) 69.07 8.74 68.89 8.86 ACD 3.10 0.38 3.07 0.35 AL 23.03 0.81 22.90 0.94 K1 (D) 42.93 1.61 43.21 1.53 K1 (mm) 7.75 0.30 7.69 0.28 K2 (D) 43.89 1.43 44.06 1.62 K2 (mm) 7.57 0.25 7.54 0.28 ACD, anterior chamber depth (mm); AL, axial length (mm); K1 + K2, keratometric values in horizontal and vertical axis in dioptres (D) and millimetres (mm). Figure 1. Image of nine macular regions: fovea (F), temporal inner macula (TIM), superior inner macula (SIM), nasal inner macula (NIM), inferior inner macula (IIM), temporal outer macula (TOM), superior outer macula (SOM), nasal outer macula (NOM), and inferior outer macula (IOM). Table 2: Comparison of measurements of macular thickness between the operated group and the control group at identical time intervals: before surgery (T), one day after surgery (T+1), 14 days after surgery (T+14) and 30 days after surgery (T+30) Macular thickness (jjm) T T+1 T+14 T+30 Aiea Gioup D Mean ± SD p N Mean ± SD D D Mean ± SD D D Mean ± SD p FM Operated 27 176.96±34.03 0.90 25 181.84±35.11 0.63 27 188.78±39.42 0.51 200.95±58.48 0.22 Control 19 187.26±35.39 19 175.74±47.47 17 180.94±36.67 14 179.50±33.03 F Operated 27 206.41±26.45 0.84 25 203.36±30.32 0.84 27 216.37±27.84 0.22 22 224.91±47.75 0.23 Control 19 204.79±25.27 19 201.42±30.30 17 205.65±28.19 14 207.93±24.12 TIM Operated 27 254.59±23.62 0.69 25 248.72±23.55 0.97 27 260.30±19.48 0.35 22 270.86±18.19 0.032 Control 19 257.00±13.52 19 248.47±17.41 17 254.76±17.88 14 257.71±15.41 SIM Operated 27 269.26±24.06 0.76 25 260.68±22.28 0.90 27 269.67±35.17 0.44 22 280.82±20.68 0.045 Control 19 267.37±12.85 19 261.47±19.77 17 282.82±76.50 14 267.50±15.08 NIM Operated 27 269.89±25.18 0.75 25 261.84±24.99 0.75 27 279.33±21.48 0.013 22 284.09±18.43 0.011 Control 19 267.84±13.72 19 264.05±18.72 17 262.24±21.25 14 207.21±12.69 IIM Operated 27 263.44±25.04 0.83 25 261.60±23.01 0.85 27 271.63±28.26 0.37 22 284.23±18.13 0.008 Control 19 264.84±16.25 19 260.37±16.76 17 264.18±22.82 14 267.07±17.07 TOM Operated 27 220.11±17.63 0.47 25 214.88±20.58 0.72 27 221.44±19.70 0.37 22 230.91±15.53 0.008 Control 19 216.32±17.32 19 217.05±18.50 17 216.29±15.34 14 216.50±14.15 SOM Operated 27 239.52±20.81 0.26 25 228.40±22.30 0.67 27 237.15±31.45 0.52 22 244.82±15.72 0.030 Control 19 233.00±16.13 19 230.89±16.85 17 231.71±17.88 14 233.36±13.17 NOM Operated 27 249.37±23.64 0.73 25 242.40±28.28 0.54 27 260.78±21.09 0.025 22 265.32±23.70 0.047 Control 19 251.47±14.40 19 247.05±18.62 17 246.29±18.37 14 250.50±15.95 IOM Operated 27 226.19±15.22 0.92 25 224.60±24.24 0.78 27 235.59±24.97 0.19 22 244.77±21.51 0.003 Control 19 226.63±15.77 19 226.68±23.37 17 226.94±10.72 14 224.64±11.70 Foveal minimum (FM), fovea (F), temporal inner macula (TIM), superior inner macula (SIM), nasal inner macula (NIM), inferior inner macula (IIM), temporal outer macula (TOM), superior outer macula (SOM), nasal outer macula (NOM), inferior outer macula (IOM) between measurements T and T+1 and in the area NOM between measurements T and T+14 (Table 3). Measurements of volumes in macular regions showed a significant difference in total macular volume (TMV) between the operated group and the control group 30 days after surgery (V+30). A significant difference between the two groups was observed 14 days after surgery (V+14) in the nasal quarter of the macula (NIM, NOM) and 30 days after surgery in all parafoveal regions except the NOM. A significant difference in volumes was not observed between the operated group and the control group in the region of the fovea (p>0.05) (Table 4). When comparing the volumes in the operated group, we found significant differences between measurements V and V+14 in the fovea and parafoveal region NIM, as well as between V and V+30 differences in the region of the fovea, in all parafoveal regions except the superior quarter and in TMV (p<0.05). The control group showed a significant difference between V Table 3: Comparison of macular thickness on the day before surgery (T) with measurements 1 day after surgery (T+1), 14 days after surgery (T+14) and 30 days after surgery (T+30) in operated and control groups Pair comparison between T and T+1 T andT+14 T and T+30 Area Group p p p FM Operated 0.428 0.096 0.057 Control 0.642 0.946 0.482 F Operated 0.873 0.035 0.092 Control 0.218 0.895 0.636 TIM Operated 0.316 0.113 0.009 Control 0.022 0.299 0.733 SIM Operated 0.115 0.945 0.093 Control 0.157 0.421 0.621 NIM Operated 0.331 0.016 0.009 Control 0.371 0.103 0.792 IIM Operated 0.979 0.132 0.001 Control 0.093 0.779 0.699 TOM Operated 0.340 0.692 0.006 Control 0.809 0.868 0.436 SOM Operated 0.063 0.604 0.296 Control 0.517 0.713 0.978 NOM Operated 0.610 0.070 0.044 Control 0.123 0.039 0.325 IOM Operated 0.917 0.060 0.000 Control 0.989 0.943 0.414 and V+1 in the area TIM and between measurements V and V+14 in the area NOM (Table 5). Measured values of RNFL before surgery compared with measurements one day after surgery, 14 days after surgery, and 30 days after surgery showed no significant differences in vertical or horizontal directions in the operated group or in the control group (Table 6). surgery may also cause retinal damage, which could be intense (cystoid macular oedema) or minor (subclinical) and which does not affect visual acuity but which can be detected with OCT. OCT as a diagnostic method represents a completely new approach to retinal-choroidal evaluation. The method is simple, objective, non-contact, reproducible and well tolerated by patients. DISCUSSION Cataract surgery has advanced greatly in recent years. Although it is a minimally invasive procedure, cataract Several studies in recent years have focused on macular changes after cataract surgery with OCT but consistency between the results (2,3,9,10,17-20). A related study in Turkey compared values of retinal thickness before Table 4: Comparison of measurements of macular volume between the operated and the control group at identical time intervals: before surgery (V), 1 day after surgery (V+1), 14 days after surgery (V+14) and 30 days after surgery (V+30) Volume (mm3) V V+1 V+14 V+30 Aiea Gioup N Mean ± SD D D Mean ± SD D D Mean ± SD D D Mean ± SD p FM Operated 27 0.162±0.021 0.826 25 0.162±0.017 0.623 27 188.78±39.42 0.224 22 0.180±0.031 0.089 Control 19 0.161±0.020 19 0.159±0.026 17 180.94±36.67 14 0.163±0.019 F Operated 27 0.401±0.038 0.759 25 0.391±0.037 0.950 27 216.37±27.84 0.355 22 0.426±0.029 0.034 Control 19 0.404±0.021 19 0.391±0.027 17 205.65±28.19 14 0.405±0.024 TIM Operated 27 0.423±0.038 0.782 25 0.410±0.035 0.914 27 260.30±19.48 0.615 22 0.441±0.033 0.043 Control 19 0.420±0.020 19 0.411±0.031 17 254.76±17.88 14 0.420±0.024 SIM Operated 27 0.424±0.039 0.766 25 0.412±0.039 0.759 27 269.67±35.17 0.010 22 0.447±0.029 0.009 Control 19 0.421±0.021 19 0.415±0.029 17 282.82±76.50 14 0.425±0.020 NIM Operated 27 0.414±0.039 0.830 25 0.412±0.036 0.863 27 279.33±21.48 0.366 22 0.447±0.029 0.007 Control 19 0.416±0.026 19 0.410±0.027 17 262.24±21.25 14 0.420±0.027 IIM Operated 27 1.169±0.093 ■0.463. 25 1.141±0.109 0.719 27 271.63±28.26 0.365 22 1.226±0.082 0.008 Control 19 1.149±0.092 19 1.153±0.098 17 264.18±22.82 14 1.150±0.076 TOM Operated 27 1.272±0.110 0.258 25 1.213±0.119 0.698 27 221.44±19.70 0.564 22 1.300±0.083 0.027 Control 19 1.237±0.085 19 1.226±0.089 17 216.29±15.34 14 1.239±0.070 SOM Operated 27 1.324±0.126 0.726 25 1.289±0.150 0.568 27 237.15±31.45 0.020 22 1.408±0.124 0.051 Control 19 1.336±0.077 19 1.312±0.098 17 231.71±17.88 14 1.331±0.084 NOM Operated 27 1.201±0.081 0.934 25 1.193±0.128 n Q/l /1 27 260.78±21.09 0.131 22 1.300±0.114 0.003 Control 19 1.203±0.083 19 1.96±0.102 0.944 17 246.29±18.37 14 1.193±0.062 IOM Operated 27 6.795±0.447 0.734 25 6.628±0.545 n 7/1 /1 27 235.59±24.97 0.920 22 7.182±0.432 ' 0.003 Control 19 6.752±0.356 19 6.677±0.399 0.744 17 226.94±10.72 14 6.750±0.326 Total macular volume (TMV). surgery with measurements 1 day, 1 week, 1 month, 3 and 6 months after cataract surgery and found that average retinal thickness increased with each measurement; this was in accordance with the present study (p>0.05). The greatest increase in retinal thickness was obtained 1 month after surgery (p<0.05) after a gradual decrease 3 and 6 months after surgery. Six months after surgery, macular thickness remained significantly greater than before the procedure (3). ments from the first postoperative day. They found a significant increase in minimal retinal thickness 30 and 90 days after surgery. Foveal volume increased at the same time periods (p<0.05). There was also a significant increase in TMV on postoperative days 7, 30 and 90 (17). A similar study confirmed an increase in retinal thickness in the perifoveal area (3 mm and 6 mm) on days 7, 30 and 60 after cataract surgery (18). One group of researchers compared retinal thickness at postoperative days 7, 30 and 90 with measure- Von Jagow, Ohrloff and Kohnen reported an increase in retinal thickness at the thinnest point of the macu- Table 5: Comparison of the macular volume on the day before surgery (V) with measurements 1 day after surgery (V+1), 14 days after surgery (V+14) and 30 days after surgery (V+30) in operated and control groups Pair comparison between V and V+1 V andV+14 V and V+30 Aiea Gioup p p p F Operated 0.681 0.036 0.015 Control 0.477 0.922 0.712 TIM Operated 0.277 0.145 0.012 Control 0.023 0.323 0.738 SIM Operated 0.124 0.946 0.089 Control 0.146 0.249 0.563 NIM Operated 0.354 0.008 0.008 Control 0.366 0.100 0.851 IIM Operated 0.957 0.131 0.001 Control 0.154 0.772 0.755 TOM Operated 0.332 0.716 0.007 Control 0.821 0.877 0.445 SOM Operated 0.064 0.603 0.287 Control 0.502 0.872 0.963 NOM Operated 0.652 0.072 0.050 Control 0.125 0.030 0.328 IOM Operated 0.935 0.066 0.000 Control 0.660 0.962 0.434 TMV Operated 0.297 0.813 0.000 Control 0.281 0.231 0.710 la on the first postoperative day. The same study also revealed that foveal thickness increases on the first postoperative day and remains increased 6 weeks after surgery. Von Jagow et al. and Cagini et al. did not find a correlation between the increased foveal thickness and reduced visual acuity (2,19). study found an increase in foveal thickness 1 week, 1 month and 3 months after cataract surgery (p<0.05) and a non-significant difference in foveal thickness 6 months after the procedure. However, the greatest increase in thickness of the entire macula was seen 1 month after surgery (20). One study that compared a group of patients without postoperative complications with a group that developed macular oedema after cataract surgery found an increase in macular thickness in both investigated groups 1 month after surgery (10). Another Conversely, one group of researchers encountered a significant increase in measurements of foveal thickness on the first day after surgery and a reduction to preoperative values 1 month after cataract surgery (9). Table 6: Measured values of RNFL before surgery compared with measurements 1 day after surgery (RNFL+1), 14 days after surgery (RNFL+14) and 30 days after surgery (RNFL+30) in operated and control groups Pair comparison between RNFL and RNFL+1 RNFL and RNFL+14 RNFL and RNFL+30 Direction Group p p p Horizontal Operated 0.576 0.644 0.968 Control 0.810 0.522 0.134 Vertical Operated 0.650 0.880 1.00 Control 0.968 0.691 0.297 Retinal fibre layer (RNFL) We wanted to confirm the hypothesis that macular thickness increases 1 month after cataract surgery. After completing the diagnostic procedures and statistical analyses, an increase in macular thickness was found 2 weeks after cataract surgery in the macular centre-fovea and in the perifoveal region NIM (p<0.05). Four weeks after cataract surgery, the whole perifoveal region with the exception of the superior quarter had significantly different values compared with those on the day before surgery. When comparing macular thickness between the operated group and the control group, differences were found in measurements carried out 14 days and 30 days after the surgical procedure. A significant difference between the two groups was found in the nasal quarter of the perifoveal macula 2 weeks after cataract surgery; however, 4 weeks after surgery, it was the thickness of the whole macular region (with the exception of the fovea) that differed from preoperative values (p<0.05). Another important finding was the increase in the volume of the fovea and perifoveal NIM 2 weeks after surgery in the operated group (p<0.05). Data analyses of the values of the same groups 1 month after cataract surgery compared with volumes before surgery showed an increase in the volume of fovea, the volume of individual perifoveal areas of the macula (TIM, NIM, IIM, TOM, NOM, IOM) and in the TMV (p<0.05). Comparison of volumes between two the operated group and control group revealed that the groups differed 2 weeks after surgery in the nasal macular perifoveal region (NIM and NOM) and 4 weeks after surgery in the TIM, SIM, NIM, IIM, TOM, SOM, IOM as well as TMV (p<0.05). One study recently reported a statistically important increase in RNFL thickness between values measured on the first postoperative day and 1 month after cataract surgery (8). We also investigated the change in RNFL thickness after cataract surgery. Postoperative RNFL values in the operated group did not show an increase compared with preoperative values. Comparison of the average RNFL values of the control group showed a non-significant decrease of these values in follow-up measurements in horizontal and vertical directions. There was a difference between the operated group and control group with respect to RNFL thickness in horizontal and vertical directions, but this difference was significant only in the vertical direction. In the vertical direction, the average RNFL thickness in the control group was smaller compared with preoperative values in the operated group. In conclusion, these results confirmed, in comparison with preoperative values, an increase in thickness of all macular regions 4 weeks after cataract surgery, with a non-significant increase in the fovea and superior perifoveal quarter of the macula. A longer follow-up period is necessary to determine if these changes in macular thickness after cataract surgery are temporary and reversible. REFERENCES 1. Trpin S, Pahor D. Medoperativni zapleti med fako-emulzifikacijo pri kratkovidnih očeh. Zdrav vestn 2005; 74: 603-5. 2. Von Jagow B, Ohrloff C, Kohnen T. Macular thickness after uneventful cataract surgery determined by optical coherence tomography. Graefes Arch Clin Exp Ophthalmol 2007; 245: 1765-71. 3. Perente I, Utine CA, Ozturker C, Cakir M, Kaya V, Eren H, et al. Evaluation of macular changes after uncomplicated phacoemulsification surgery by optical coherence tomography. Curr Eye Res 2007; 32: 241-7. 4. Yanoff M, Duker J, et al. Ophthalmology. 2nd ed. Mosby; 2004. 5. Obstbaum SA. Biologic relationship between polymethylmethacrylate intraocular lenses and uveal tissue. J Cataract Refract Surg 1992; 18: 219-31. 6. Williamson J. Incidence of eye disease in cases of connective tissue disease. Trans Ophthalmol Soc UK 1974; 94: 742-52. 7. Pahor D, Pahor A, Gračner B. Postoperative Inflammation after Cataract Surgery in Patients with Rheumatoid Arthritis. Ophthalmologica 2001; 215: 174-8. 8. Pareja-Esteban J, Teus-Guezala MA, Drake-Casanova P, Dapena-Sevilla I. Retinal nerve fiber layer changes after cataract surgery measured by OCT: a pilot study. Arch soc esp oftalmol 2009; 84: 30510. 9. Georgopoulos G, Papaconstantinou D, Niskop-oulou M, Moschos M, Georgalas I, Koutsandrea C. Foveal thickness after phacoemulsification as measured by optical coherence tomography. Clin Ophthalmol 2008; 2(4): 817-20. 10. Kim SJ, Belair ML, Bressler NM, Dunn JP, Thorne JE, Kedhar SR, et al. A method of reporting macular edema after cataract surgery using optical coherence tomography. Retina 2008; 28(6): 870-6. 11. Pahor D, Gračner B, GračnerT,et al. Optical coherence tomography findings in hemodialysis patients. Klin Monatsbl Augenheilkd 2008; 225: 713-7. 12. Jaffe GJ, Caprioli J. Optical coherence tomography to detect and manage retinal disease and glaucoma. Am J Ophthalmol 2004; 137: 156-69. 13. Ko TH, Fujimoto JG, Schuman JS, et al. Comparison of ultrahigh- and standard-resolution optical coherence tomography for imaging macular pathology. Ophthalmology 2005; 112: 1922.e1-15. 14. Youngquist RC, Carr S, Davies DEN. Optical coherence domain reflectometry: a new optical evaluation technique. Opt Lett 1987; 12: 158-60. 15. Knez N, Šiško K. Debelina roženice pri bolnikih s starostno degeneracijo makule (raziskovalno delo). Maribor: Univerza v Mariboru; 2008. 16. Knez N, Šiško K, Pahor D. Corneal Thickness in Patients with Age-related Macular Degeneration. J Int Med Res 2009; 37(5): 1552-60. 17. Kecik D, Makowiec-Tabernacka M, Golebiewska J, Moneta-Wielgos J, Kasprzak J. Macular thickness and volume after uncomplicated phacoemulsification surgery evaluated by optical coherence tomography. A one-year follow-up. Neuro Endocrinol Lett 2009; 30(5): 610-4. 18. Biró Z, Balla Z. OCT measurements on foveal and perifoveal retinal thickness on diabetic patients after phacoemulsification and IOL implantation. Eye 2010; 24: 639-47. 19. Cagini C, Fiore T, Iaccheri B, Piccinelli F, Ricci MA, Fruttini D. Macular thickness measured by optical coherence tomography in a healthy population before and after uncomplicated cataract phacoemulsification surgery. Curr Eye Res 2009; 34(12): 1036-41. 20. Yazici AT, Bozkurt E, Altan CD, Albayrak S, Cakir M, Alagoz N, Yilmaz OF. Macular thickness changes after phacoemulsification combined with primary posterior curvilinear capsulorhexis. Eur J Ophthalmol 2010; 20(2): 376-80.