Purpose
To evaluate the characteristics of rhegmatogenous retinal detachment (RD) in patients with previous laser in situ keratomileusis (LASIK) and compare them to RD in patients with previous laser assisted subepithelial keratomileusis (LASEK) and myopic patients with no previous refractive surgery.
Design
Retrospective, comparative case series.
Methods
In 106 eyes of 106 patients with RD, patients with previous refractive surgery included 21 eyes after LASIK and 13 eyes after LASEK; 72 myopic patients with refractive errors of −3.0 diopters or less were grouped as the R (−) group. Characteristics of RD included distribution of RD and associated retinal breaks, location and number of retinal breaks, presence of lattice degeneration, and axial lengths.
Results
The mean interval between refractive surgery and the onset of rhegmatogenous RD was 63.7 ± 43.5 months, occurring across a broad spectrum of time intervals. There were no significant differences among the LASIK group, the LASEK group, and the R (−) group in axial length (26.8 mm vs 26.4 mm vs 26.9 mm, respectively); in mean number of retinal holes/tears, (2.1/1.5, 0.9/1.4, 1.5/1.6, respectively); or in the presence of lattice degeneration (52.4% vs 46.2% vs 43.1%, respectively). Distribution of RD and associated retinal breaks were also not significantly different; retinal holes and tears were more prevalent in the temporal quadrants, and inferotemporal quadrants were the most commonly detached areas in both the LASEK and LASIK groups and in the R (−) group.
Conclusions
Myopia is a well-known risk factor for rhegmatogenous RD and may contribute more to the development of RD in myopic patients after refractive surgery, rather than refractive surgery itself.
Rhegmatogenous retinal detachment (RD), the most common type of RD, is caused by liquefied vitreous passing through a retinal break into the subretinal space, separating the neurosensory retina from the retinal pigment epithelium. Fundamental mechanisms leading to rhegmatogenous RD are largely unknown. The formation of retinal breaks is often preceded by vitreoretinal degeneration, the cause of which is unclear.
One of the factors strongly associated with rhegmatogenous RD is myopia. Low myopes (−0.75 to −2.75 diopters [D]) show an odds ratio of 3.14 for RD, and the odds ratio was shown to rise steeply with increasing myopic refractive errors in the Japanese population. Increased vitreous liquefaction, earlier posterior vitreous detachment, and higher incidence of vitreoretinal degeneration such as lattice degeneration are thought to be attributable to the higher prevalence in rhegmatogenous RD in myopes.
Refractive surgeries, such as laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratomileusis (LASEK), have been popularized for correction of low to moderate myopia. Vision-threatening posterior segment complications can occur after refractive surgeries; they include macular hemorrhages, macular holes, and rhegmatogenous RD. The reported incidence of rhegmatogenous RD in those with histories of LASIK is not high, ranging from 0.033% to 0.25%. However, many have regarded a suction ring application during LASIK to be a potential risk factor for rhegmatogenous RD because this procedure may induce vitreous traction and detachment resulting from sudden decompression of the eye. A previous study found that retinal breaks were more commonly located in the inferotemporal quadrant in rhegmatogenous RD after LASIK. Whether this feature is characteristic of rhegmatogenous RD after LASIK is unclear because this finding was not compared to rhegmatogenous RD without prior LASIK.
Herein, we studied the characteristics of rhegmatogenous RD in patients with previous LASIK and compared them to both rhegmatogenous RD in myopic patients with no previous refractive surgeries and to rhegmatogenous RD in patients with previous LASEK, which does not require a suction ring application, unlike LASIK.
Methods
Enrollment of Study Subjects
We retrospectively reviewed 106 eyes of 106 patients who fulfilled the inclusion criteria at the Vitreoretinal Service Clinic of Yonsei University Medical Center between March 2007 and March 2012. This retrospective, comparative case series was performed with the approval of the Institutional Review Board of Yonsei University College of Medicine and conducted in accordance with the tenets of the Declaration of Helsinki. Inclusion criteria were patients with (1) nontraumatic rhegmatogenous RD who underwent surgical repair; (2) no previous surgical history other than corneal laser refractive surgery for the study group; and (3) −3.0 D or lower myopia without previous refractive surgery for the control group. Patients with concomitant ocular diseases, such as diabetic retinopathy, myopic choroidal neovascularization or uveitis at the time of surgery were excluded. The patients included 34 eyes of 34 patients who had histories of refractive surgery before the onset of rhegmatogenous RD (21 eyes after LASIK and 13 eyes after LASEK), and they were grouped as the refractive surgery group (R [+] group). The remaining 72 myopic patients without previous refractive surgery were grouped as the nonrefractive surgery group (R [−] group), or the control group. The control group was selected to include moderately myopic patients who would be typical candidates for LASIK or LASEK. Because of a lack of information about refractive errors before refractive surgery for the R (+) group, the axial lengths of the affected eyes were used to confirm and compare the degrees of myopia between the R (+) and the R (−) groups. No patient in the R (+) group showed myopic posterior staphyloma, so highly myopic patients with posterior staphyloma were excluded in the R (−) group.
Examination
All patients received complete ocular examinations, including best-corrected visual acuity (BCVA), color fundus photography and ultrasonography. Follow-up visits were arranged in general at 1 week and 1 month after each surgery. Subsequent 3- to 6-month examinations were performed; they included BCVA and dilated fundus examinations with an indirect ophthalmoscope.
Statistical Analysis
Patients’ characteristics were retrieved from their medical charts, including age at refractive surgery and development of rhegmatogenous RD, sex, and axial lengths (mm). BCVA by decimal visual acuity charts were converted into logarithm of the minimum angle of resolution (logMAR) values for statistical analysis. We evaluated the characteristics of RD, including numbers and locations of retinal tears and holes and the presence of lattice degeneration. In addition, rhegmatogenous RD extent (involved quadrants), location of the detached retina, and status of the macula (detached labeled as off and attached as on ) were investigated by reviewing the operation notes. The rhegmatogenous RD eyes were also classified as 1 of 3 types: equatorial, oral or macular.
SPSS Statistics 18.0 software for Windows (IBM, Somers, NY, USA) was used for statistical analysis. The Kolmogrov-Smirnov test was used to confirm normal distribution of the study population. For comparison of the eyes with and without prior refractive surgery, the Student t test for continuous variables and the χ 2 test for categorical variables were used. For subgroup analysis, nonparametric analysis was used: the Mann-Whitney U test for continuous variables and the Wilcoxon signed-rank test for categorical variables. Results with P less than 0.05 were considered statistically significant.
Results
Characteristics of the Patients
In 106 eyes of 106 patients, 34 eyes (34 patients) had histories of refractive surgery, whereas 72 eyes (72 patients) with myopia had had no previous refractive surgery. Of the patients, 56 (52.8%) were male, including 14 males with prior refractive surgery and 42 patients with myopic RD. The mean follow-up period after retinal reattachment surgery was 13.5 ± 4.6 months. All patients achieved retinal reattachment after surgery, among which 10 eyes (9.4%) underwent surgical repair of redetached retina. After RD surgery, mean BCVA improved from 0.76 ± 0.88 logMAR (Snellen equivalent 20/115) at baseline to 0.38 ± 0.67 logMAR (Snellen equivalent 20/47) at the last follow-up visits ( P = .001). The mean age at rhegmatogenous RD onset was 33.6 ± 9.8 years and mean symptom duration was 3.1 ± 6.8 weeks in symptomatic cases. In all patients, 19 eyes of 19 patients had no visual symptoms, and rhegmatogenous RD was diagnosed during a routine fundus examination.
Of 34 eyes with prior refractive surgery, 21 eyes (61.8%) underwent LASIK and 13 eyes (38.2%) received LASEK. The mean age at the time of refractive surgery was 29.6 ± 7.8 years, and the mean interval between refractive surgery and rhegmatogenous RD onset was 63.7 ± 43.5 months. None of the patients with prior refractive surgery received any treatment with barrier laser at the time of refractive surgery. The distribution of patients according to the interval between refractive surgery and rhegmatogenous RD onset is shown in Figure 1 . The mean refractive errors in 72 patients in the R (−) group were −4.5 ± 4.0 D in affected eyes and −4.6 ± 4.4 D in unaffected eyes.
Comparison Between Eyes With Prior LASIK and LASEK
The mean age at the time of refractive surgery was 31.5 ± 7.8 years in the LASIK group and 26.5 ± 6.9 years in the LASEK group ( P = .063). The mean age at onset of rhegmatogenous RD was older in the LASIK group (38.4 ± 8.8 years) than in the LASEK group (28.9 ± 8.2 years) ( P = .003). The mean interval between refractive surgery and onset of rhegmatogenous RD was longer in the LASIK group (85.8 ± 37.9 months) than in the LASEK group (28.1 ± 23.9 months) ( P = .001). The mean axial length was not significantly different in the 2 groups: 26.8 ± 1.7 mm in the LASIK group and 26.4 ± 0.8 mm in the LASEK group ( P = .398). Mean BCVA at baseline was 0.75 ± 0.73 logMAR (Snellen equivalent 20/112) in the LASIK group and 0.69 ± 0.42 logMAR (Snellen equivalent 20/97) in the LASEK group ( P = .425). Mean BCVA improved in both groups after RD surgery when compared with baseline: 0.28 ± 0.21 logMAR (Snellen equivalent 20/38) in the LASIK group, and 0.13 ± 0.26 logMAR (Snellen equivalent 20/26) in the LASEK group ( P = .210). There were no statistically significant differences between the 2 groups in characteristics of rhegmatogenous RD and retinal breaks ( Table 1 ). The distribution of retinal breaks of each group is shown in Figure 2 .
| LASIK group (n = 21) | LASEK group (n = 13) | P value a , b | |
|---|---|---|---|
| Retinal breaks | .399 b | ||
| Retinal hole only | 11 (52.4%) | 8 (61.5%) | |
| Retinal tear only | 5 (23.8%) | 4 (30.8%) | |
| Both | 5 (23.8%) | 1 (7.7%) | |
| Mean number of retinal holes (per eye) | 2.1 ± 2.1 | 0.9 ± 0.7 | .054 a |
| Mean number of retinal tears (per eye) | 1.5 ± 0.6 | 1.4 ± 0.5 | .492 a |
| Lattice degeneration | 11 (52.4%) | 6 (46.2%) | .658 b |
| Macula attached at baseline | 8 (38.1%) | 5 (38.5%) | .929 b |
| Location of retinal holes (quadrants) | .765 b | ||
| Superotemporal | 5 (31.3%) | 1 (11.1%) | |
| Superonasal | 1 (6.3%) | 2 (22.2%) | |
| Inferotemporal | 8 (50.0%) | 6 (66.7%) | |
| Inferonasal | 2 (12.4%) | 0 (0.0%) | .366 b |
| Location of retinal tears (quadrants) | |||
| Superotemporal | 2 (20.0%) | 3 (60.0%) | |
| Superonasal | 3 (30.0%) | 0 (0.0%) | |
| Inferotemporal | 4 (40.0%) | 2 (40.0%) | |
| Inferonasal | 1 (10.0%) | 0 (0.0%) | |
| Detached area | .398 b | ||
| Superonasal quadrants | 2 (9.5%) | 1 (7.6%) | |
| Superotemporal quadrants | 2 (9.5%) | 4 (30.8%) | |
| Inferonasal quadrants | 1 (4.8%) | 0 (0.0%) | |
| Inferotemporal quadrants | 0 (0.0%) | 3 (23.1%) | |
| Inferior half | 7 (33.3%) | 3 (23.1%) | |
| Superior half | 5 (23.8%) | 2 (15.4%) | |
| Temporal half | 3 (14.3%) | 0 (0.0%) | |
| Nasal half | 0 (0.0%) | 0 (0.0%) | |
| Total | 1 (4.8%) | 0 (0.0%) |
a Mann-Whitney U test for continuous variables.
Comparison Between Eyes With Prior LASIK and Myopic Eyes With No Previous Refractive Surgery
We compared the eyes with prior LASIK (LASIK group) and myopic eyes without previous refractive surgery (R [−] group). The mean age at rhegmatogenous RD onset was older in the LASIK group (38.4 ± 8.8 years) than in the R (−) group (33.1 ± 9.9 years) ( P = .029). The mean axial length was 26.83 ± 1.73 mm in the LASIK group and 26.9 ± 1.8 mm in the R (−) group ( P = .893). The mean BCVA at baseline was 0.75 ± 0.73 logMAR (Snellen equivalent 20/112) in the LASIK group, and 0.85 ± 0.96 logMAR (Snellen equivalent 20/141) in the R (−) group ( P = .662). Mean BCVA at last visit was 0.28 ± 0.21 logMAR (Snellen equivalent 20/38) in the LASIK group and 0.41 ± 0.38 logMAR (Snellen equivalent 20/51) in the R (−) group ( P = .106). The distribution of rhegmatogenous RD and associated retinal breaks were not significantly different in the 2 groups, as shown in Table 2 .
| LASIK group (n = 21) | Nonrefractive group (n = 72) | P value a , b | |
|---|---|---|---|
| Mean number of retinal holes (per eye) | 2.1 ± 2.1 | 1.5 ± 1.8 | .237 a |
| Mean number of retinal tears (per eye) | 1.5 ± 0.6 | 1.6 ± 0.7 | .492 a |
| Retinal breaks | .399 b | ||
| Retinal hole only | 11 (52.4%) | 35 (48.6%) | |
| Retinal tear only | 5 (23.8%) | 27 (37.5%) | |
| Both | 5 (23.8%) | 10 (13.9%) | |
| Macula attached at baseline | 8 (38.1%) | 30 (41.7%) | .729 b |
| Lattice degeneration | 11 (52.4%) | 31 (43.1%) | .578 b |
| Location of retinal holes (quadrant) | .765 b | ||
| Superotemporal | 5 (31.3%) | 13 (25.0%) | |
| Superonasal | 1 (6.3%) | 4 (7.7%) | |
| Inferotemporal | 8 (50.0%) | 27 (51.9%) | |
| Inferonasal | 2 (12.4%) | 8 (15.4%) | |
| Location of retinal tears (quadrant) | .366 b | ||
| Superotemporal | 2 (20.0%) | 10 (24.4%) | |
| Superonasal | 3 (30.0%) | 14 (34.2%) | |
| Inferotemporal | 4 (40.0%) | 11 (26.8%) | |
| Inferonasal | 1 (10.0%) | 6 (14.6%) | |
| Detached area | .525 b | ||
| Superonasal quadrant | 2 (9.5%) | 2 (2.8%) | |
| Superotemporal quadrant | 2 (9.5%) | 8 (11.0%) | |
| Inferonasal quadrant | 1 (4.8%) | 1 (1.4%) | |
| Inferotemporal quadrant | 0 (0.0%) | 9 (12.5%) | |
| Inferior half | 7 (33.3%) | 21 (29.2%) | |
| Superior half | 5 (23.8%) | 10 (13.9%) | |
| Temporal half | 3 (14.3%) | 13 (18.1%) | |
| Nasal half | 0 (0.0%) | 3 (4.2%) | |
| Total | 1 (4.8%) | 5 (6.9%) |
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