Retinal detachment after phacoemulsification cataract extraction

Retinal detachment after phacoemulsification cataract extraction Gøril Boberg-Ans, MD, Jørgen Villumsen, MD, DMSc, Vibeke Henning, MD Purpose: To estimate the incidence of retinal detachment (RD) after phacoemulsification cataract extraction in an unselected group of patients. Setting: Herlev University Hospital, Copenhagen, Denmark. Methods: This retrospective review comprised 6521 cataract patients who had phacoemulsification over a 3-year period. The incidence of postoperative RD and the risk factors were assessed. Results: During the 15- to 52-month observation period, 22 cases of RD in 21 patients were observed, with an estimated risk (Kaplan-Meier) of 0.41% (95% confidence limit, 0.25%-0.57%) at 52 months. The results confirmed recognized preoperative risk factors for RD such as an axial length greater than 25.0 mm (P⬍.001), age younger than 65 years (P⬍.001), and male sex (P⬍.02). In 18 eyes, the retina was reattached after 1 operation. Conclusions: The incidence of RD after phacoemulsification cataract extraction in an unselected group of patients was low. A long axial length, young age, and male sex were confirmed as risk factors. J Cataract Refract Surg 2003; 29:1333–1338 © 2003 ASCRS and ESCRS

From the Department of Ophthalmology, Herlev University Hospital, Herlev, Denmark.

loss are well-known risk factors for RD after ECCE.3 Neodymium:YAG (Nd:YAG) capsulotomy also increases the risk.8,12–15 The rate of Nd:YAG treatment for posterior capsule opacification varies significantly among studies and may be associated with different approaches to cataract extraction and the selection of the intraocular lens (IOL). Thus, the expected rate of RD is influenced by the selection of patients with or without risk factors and by the quality of the surgery. The incidence of RD after cataract extraction and the risk factors have been evaluated in several studies.1–17 Although RD is rare, a possible consequence is significant loss of vision. This study reports the incidence of RD in an unselected population having phacoemulsification at 1 hospital over a 3-year period.

Presented at the XVIIIth Congress of the European Society of Cataract & Refractive Surgeons, Brussels, Belgium, September 2000.

Patients and Methods

R

etinal detachment (RD) is a recognized complication of cataract extraction.1 The risk depends on the technique used to remove the crystalline lens. The incidence of RD after intracapsular cataract extraction is up to 5.7%2– 8 and after extracapsular cataract extraction (ECCE), 0.41% to 1.70%.1,6,8 –10 Although there are few studies of the incidence of RD after phacoemulsification,8,9,11–13 it seems that the risk is less than after conventional ECCE. A long axial length, preexisting eye disease, and intraoperative complications such as posterior capsule rupture and vitreous Accepted for publication November 4, 2002.

None of the authors has a financial or proprietary interest in any material or method mentioned. Reprint requests to Gøril Boberg-Ans, MD, Department of Ophthalmology, Herlev University Hospital, Herlev Ringvej 75, DK 2730, Herlev, Denmark. © 2003 ASCRS and ESCRS Published by Elsevier Inc.

This retrospective review comprised 6521 cataract patients who had phacoemulsification at the Department of Ophthalmology, Herlev University Hospital, Copenhagen, from January 1, 1996, through December 31, 1998. Excluded from the study were patients with RD before cataract surgery 0886-3350/03/$–see front matter doi:10.1016/S0886-3350(03)00057-9

RETINAL DETACHMENT AND PHACOEMULSIFICATION

The chi-square test with Yates continuity correction with 1 degree of freedom was used for statistical analysis of the risk factors for RD. Because of the uneven sex ratio in the different age groups, the expected number of men was calculated for each age group using data from the Danish national statistics (www.dst.dk/yearbook). The result was then compared to the observed number. Other statistical evaluation was by the chisquare test with Yates continuity correction and 8 degrees of freedom. All confidence limits (CLs) shown indicate 95% limits.

Results

Figure 1. (Boberg-Ans) Age of 6521 patients having phacoemulsification over a 3-year period. There are significantly fewer males than would be expected if the operation rate were evenly distributed between women and men (P⬍.02).

Figure 2. (Boberg-Ans) The estimated number of patients without RD after cataract extraction at 52 months (Kaplan-Meier estimate). The risk for RD was estimated at 0.41% (95% CL, 0.25%- 0.57%).

and those who had lens extraction during posterior segment surgery for any reason. Eleven surgeons performed the operations using the same technique. Six of the surgeons had performed 600 or more operations per year, and 5 were trainees with less surgical volume. In almost all cases, phacoemulsification was performed using 2-handed down-slope sculpting, nuclear cracking, and phacoaspiration of the fragments using a Storz Premiere unit with the standard setting as follows: energy 40%; aspiration 40 mm Hg during sculpting and 120 mm Hg with a 7 Hz pulse during nuclear aspiration. Irrigation/aspiration was used to polish the capsular bag if necessary. The infusion bottle was placed 40 to 95 cm above the eye. A few patients had surgery by other techniques, including 65 by conventional ECCE. All IOLs used were approved by the U.S. Food and Drug Administration and included the Pharmacia 809P poly(methyl methacrylate), Storz Hydroview H60M foldable, Allergan SI-40 foldable silicone, and Alcon AcrySof威 MA30. The incidence of RD was assessed by matching the personal identification number of each patient with the diagnosis of RD in a central register. This identified patients having surgery for RD in other eye departments in Denmark. Surgery for RD is only done at 1 clinic outside the public health system in Denmark, and no patient included had been treated for RD at that clinic. 1334

Figure 1 shows the age distribution of the study population. Most patients were between 70 and 85 years; 1119 (17.1%) were younger than 65 years. The median age was 76 years. The study included 4304 women (66.0%) and 2217 men (34.0%). The difference between the number of women and men was significant (P⬍.001). The axial length was 25.0 mm or greater in 10.2% of patients. In the 15- to 52-month observation period, 22 cases of RD in 21 patients were observed, yielding a risk of 0.32% (95% CL, 0.18%-0.46%). The accumulated risk (Kaplan Meier) at 52 months was estimated at 0.41% (95% CL, 0.25%-0.57%) (Figure 2). All 22 eyes with RD had phacoemulsification, and 20 had the IOL implanted in the capsular bag. One eye had an anterior chamber IOL and 1, a sulcus-fixated posterior chamber lens. A summary of the recorded data for each patient is shown in Table 1and the age characteristics, in Figure 3.

Figure 3. (Boberg-Ans) Age of the 21 patients (22 eyes) with RD after cataract extraction. The patient with bilateral RD was a man in the 40- to 50-year age group. There were more men with RD than would be expected from the age characteristics shown in Figure 1 (P⬍.02).

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Table 1. Characteristics of patients with RD.

No

Axial Age Length (Y) (mm)

Preoperative Eye Disease

1

66

25.34

—

—

—

X

0.3

0.7

0.5

X

2

63

24.28

Glaucomatous iridocyclitis

—

—

—

X

0.3

0.2

CF

—

3*

68

23.04

Toxoplasmic uveitis

—

4.0

—

X

0.5

1.0

CF

X

4

64

26.29

—

—

—

—

—

0.4

1.0

1.0

—

5

61

23.28

—

—

6.0

—

—

0.5

0.2

0.2

X

6

39

25.68

—

—

X

HM

CF

LP

—

7

74

23.17

—

—

X

—

0.3

0.7

0.3

X

8

81

23.20

—

—

X

X

0.1

0.3

0.3

X

9

77

22.58

Trabeculectomy

—

—

—

—

0.4

0.8

0.6

X

10

56

25.21

Trauma

—

—

—

X

LP

0.3

0.4

—

11

62

25.00

—

—

—

—

X

0.1

0.9

0.3

X

12

71

25.79

—

—

—

—

0.2

0.4

0.3

X

13

73

22.17

—

—

—

X

—

CF

0.1

0.6

—

14

66

25.85

—

—

—

—

—

CF

0.9

0.6

X

15

45

16

46

25.14

—

—

—

—

X

0.3

1.0

0.9

X

25.40

—

—

—

—

X

HM

0.9

0.7

—

17

47

24.87

—

—

—

—

X

0.1

1.0

0.8

X

18

64

29.18

—

—

—

X

0.2

0.7

0.5

—

19

70

30.84

—

—

1.5

—

—

0.2

0.5

CF

X

20

50

25.57

—

—

—

—

X

CF

1.0

0.9

—

21

87

21.40

—

—

—

X

—

0.4

0.7

0.5

X

22

80

23.00

—

—

6.5

X

X

0.4

0.5

0.1

X

†

—

Time Visual Acuity from Nd:YAG No Before After Fovea Intraoperative to RD Risk Cataract Cataract After RD Centralis Complications (Mo) Factor Male Extraction Extraction Surgery Detachmant

Mature traumatic Loss of lens cataract fragments

Dense brown cataract

— Loss of lens fragments

Capsular bag rupture

CF ⫽ counting fingers; HM ⫽ hand movements; LP ⫽ light perception *Had late-onset endophthalmitis treated by IOL removal † Had vitrectomy for floaters after cataract extraction

Thirteen of the 22 RDs were in men (P⬍.02), 11 were in patients younger than 65 years at the time of cataract surgery (P⬍.001), and 12 were in eyes with an axial length greater than 25.0 mm (P⬍.001). Thus, these 3 traits led to a higher-than-expected risk for RD. Within the first year of observation, 11 cases of RD (50%) (95% CL, 28%-72%) were identified; all had at least 1 risk factor. Preoperative eye disease such as uveitis, trauma, and laser-treated lattice degeneration was

found in 3 cases (14%) (95% CL, 3%-35%), and intraoperative problems such as capsular bag rupture with loss of lens fragments with or without anterior vitrectomy occurred in 3 cases (14%) (95% CL, 3%-35%). In 2 of these patients, the axial length was greater than 25.0 mm. An Nd:YAG capsulotomy had been performed in 4 eyes (18%) (95% CL, 5%-40%) 6 weeks to 6 months before the diagnosis of RD. One patient with RD had a pars plana vitrectomy for vitreous floaters 12 months

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Figure 4. (Boberg-Ans) Snellen visual acuity before cataract surgery and after surgery for RD (CF ⫽ counting fingers; HM ⫽ hand movements; LP ⫽ light perception).

after cataract surgery followed by an Nd:YAG capsulotomy after 4 weeks; an RD developed 6 months later. Figure 4 shows the preoperative and last recorded visual acuities after RD repair. Four patients lost 2 or more lines of Snellen acuity; in the other eyes, visual acuity was unchanged or better. After cataract surgery, visual acuity was unchanged in 14 patients; 8 eyes lost 2 or more Snellen lines (Figure 5). The retina was reattached after 1 scleral buckling procedure with an encircling band in 18 eyes (82%) (95% CL, 60%-95%). After repair of the RD, the visual acuity was 0.2 to 1.0 in 16 eyes (73%) (95% CL, 50%-89%). The 6 eyes (27%) (95% CL, 11%50%) with a poor visual result had complicating eye disease such as glaucoma, uveitis, and late-onset endophthalmitis. One patient did not want treatment for the total RD. Three patients had recurrent RD; 1 developed maculopathy. Twenty eyes (90%) (95% CL, 71%-99%) had 2 or more quadrants of RD (Figure 6). Fifteen patients (68%) (95% CL, 45%-86%) had a detached macula before the buckling procedure. The retinal tears were in the upper quadrants within 2 clock hours from 12 o’clock in 12 eyes (55%) (95% CL, 36%-79%) (Figure 7). In 3 cases, no tear was found. 1336

Figure 5. (Boberg-Ans) Snellen visual acuity after cataract extraction and after surgery for RD (CF ⫽ counting fingers; HM ⫽ hand movements; LP ⫽ light perception).

Figure 6. (Boberg-Ans) The extent of the RD at the examination before surgery for RD. Symbols at bottom, from left to right: 1 quadrant; 2 quadrants; 3 quadrants; 4 quadrants.

Figure 7. (Boberg-Ans) Location of the retinal tears.

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Discussion Modern cataract extraction with ultrasoundassisted removal of hard lens fragments reduces the surgical trauma to the eye. The small incision size and intact capsular support of the anterior vitreous surface reduce the risk for vitreous prolapse during and after surgery, decreasing the risk for vitreous traction on the retina. With these factors, a lower risk for RD would be expected. However, at teaching hospitals, it is expected that complications during phacoemulsification would be more frequent at the start of the learning curve. This might result in a higher risk for complications and RD. Our study comprised unselected patients and surgeons. The patients were mainly from Copenhagen County, where several private clinics also perform cataract extraction. The population in this study did not reflect the average cataract population in the area during this period as an unknown number of cataract surgeries were performed elsewhere. Because of the preferences of the referring general ophthalmologist, the patients referred to Herlev University Hospital probably reflect a population with a higher frequency of eye disease and general health problems. In contrast, most other studies exclude patients with preoperative eye disease and intraoperative complications. Even so, we found a low incidence of RD, indicating phacoemulsification can be safely performed by trainees with experienced backup. Fewer men had cataract surgery in our study, reflecting the general pattern of cataract surgery in Denmark. The study confirmed the known risk factors for RD after cataract surgery such as a long axial length, young age, and male sex. The study was not intended to estimate the impact of Nd:YAG membranectomy on the risk for RD after cataract surgery; however, the procedure did not seem be a major risk factor in most patients. In patients with no preoperative risk factors, the incidence of RD after phacoemulsification was estimated at less than 1 in 1000. This figure is close to the general risk for RD of 1.2 in 1000 in a matched age group.1 Thus, patients without preoperative risk factors do not seem to have an increased risk for RD. Sixteen eyes obtained a visual acuity better than 0.2. However, the number of RD cases was limited. Thus, no conclusions about the prognosis of pseudophakic detachments can be made, although the prognosis seems better than in aphakic eyes with RD.18

In conclusion, the incidence of RD after phacoemulsification was low. A long axial length, age younger than 65 years at the time of surgery, and male sex were confirmed as risk factors. Without preoperative risk factors, the risk for developing RD after cataract surgery seemed to increase little if at all in our unselected group of patients operated on by experienced surgeons and surgeons in training.

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