Although remarkable progress has been achieved in the surgical treatment of eyes with rhegmatogenous retinal detachment (RRD), it is still difficult to predict postoperative visual outcomes when RRD includes a detached macula, known as macula-off RRD. Newly developed less-invasive surgical interventions, particularly 25-gauge microincision vitrectomy surgery (25GMIVS), have led to a very high initial reattachment rate for eyes with RRD, currently about 95% [
Photoreceptor apoptosis has been reported to mainly occur within 3 days of RRD onset in experimental animal models [
We hypothesized that preoperative macular volume reflected photoreceptor apoptosis and could thus predict postoperative outcomes in eyes with macula-off RRD. In order to test this hypothesis, we developed new OCT parameters that could provide a suitable evaluation of the macular structure and then determined the relationship between these parameters and postoperative visual outcomes in macula-off RRD eyes.
We performed a retrospective analysis of the medical records of 56 consecutive eyes with macula-off RRD that underwent surgical intervention with a 25-gauge trocar cannula system or scleral buckling from January 2011 to February 2014 at Tohoku University Hospital. Eyes were included only if complete reattachment of the RRD was achieved after initial surgery. Eyes were excluded if they had prior vitreoretinal surgery, proliferative retinopathy, retinal vascular disease, chorioretinal atrophy, or high myopia (more than −10 diopters), if we could not obtain clear preoperative OCT measurements due to a bullous RRD or vitreous opacity, or if a single OCT scan could not capture the detached fovea and the retinal pigment epithelium layer. After the purpose and procedures of the operation were explained, informed consent was obtained from all patients. The procedures conformed to the tenets of the Declaration of Helsinki, and the study was approved by the Institutional Review Board of Tohoku University Graduate School of Medicine.
All patients underwent a complete ocular examination 6 months after surgery. Best-corrected visual acuity (BCVA) was measured preoperatively and 1 and 6 months postoperatively with the Landolt C visual acuity chart. Decimal acuity values were converted to logarithm of the minimal angle of resolution (log MAR) units. The detached macula was examined with spectral-domain (SD) OCT (Cirrus OCT, Carl Zeiss Meditec) in all patients preoperatively, and foveal thickness was also measured 1 and 6 months postoperatively. To evaluate the detached macula preoperatively, a 2 mm circle was manually centered on the surface of the fovea in a cross-sectional OCT macular image. The image of the macula within this circle was then manually segmented into three layers: the inner layer (nerve fiber layer and ganglion cell layer), middle layer (inner plexiform layer and inner nuclear layer), and outer layer (outer plexiform layer and outer nuclear layer) (Figure
Preoperative optical coherence tomography (OCT) images. A circle with a diameter of 2 mm was manually centered at the foveal surface center of the detached macula in the OCT image. The macular area within the circle was divided into three sections: the inner layer (upper right: nerve fiber layer and ganglion cell layer), middle layer (lower right: inner plexiform layer and inner nuclear layer), and outer layer (lower left: outer plexiform layer and outer nuclear layer).
All statistical analysis was performed with JMP software (Pro version 10.0.2, SAS Institute Japan Inc., Tokyo, Japan). The correlation of 6-month postoperative BCVA to preoperative characteristics and operative, visual, and anatomical outcomes was determined with Spearman’s rank correlation coefficient. Significant differences between preoperative and 1- and 6-month postoperative BCVA were determined with the paired
Table
Preoperative characteristics and operative, visual, and anatomical outcomes of 56 eyes with rhegmatogenous retinal detachment and their possible association with 6-month postoperative visual acuity.
|
|
||
---|---|---|---|
Number of eyes | 56 | — | — |
Age (years) | 50.0 ± 19.8 | 0.09 | 0.524a |
Sex ( |
— | 0.557b | |
Male | 38, 67.9% | — | — |
Female | 18, 32.1% | — | — |
Spherical equivalent (diopter) | −3.15 ± 2.67 | −0.01 | 0.950a |
Duration of macular detachment (days) | 33.3 ± 72.7 | −0.09 | 0.565a |
Procedure ( |
— | 0.935b | |
PPV only | 10, 17.7% | — | — |
PPV with cataract surgery | 27, 48.2% | — | — |
Scleral buckling | 19, 33.9% | — | — |
Visual course (decimal VA) | |||
Preoperative | 0.19 ± 0.27 | 0.48 | <0.001a |
1 M postoperative | 0.53 ± 0.51 | 0.82 | <0.001a |
6 M postoperative | 0.69 ± 0.55 | — | — |
Pre-op OCT findings | |||
RD height (mm) | 1.45 ± 0.87 | 0.47 | <0.001a |
Total macular area (mm2) | 1.05 ± 0.16 | −0.44 | <0.001a |
Outer layer macular area (mm2) | 0.62 ± 0.13 | −0.17 | 0.221a |
Middle layer macular area (mm2) | 0.19 ± 0.06 | −0.04 | 0.759a |
Inner layer macular area (mm2) | 0.23 ± 0.08 | −0.43 | 0.001a |
Post-op OCT findings | |||
1 M postoperative FT ( |
269.9 ± 79.7 | −0.37 | 0.006a |
6 M postoperative FT ( |
255.4 ± 35.7 | −0.24 | 0.096a |
FT = foveal thickness, OCT = optical coherence tomography, PPV = pars plana vitrectomy, RD = retinal detachment, and VA = visual acuity.
aSpearman’s correlation coefficient by rank test, bunpaired
Multiple regression analysis for independent factors contributing to 6 M postoperative VA.
Variable |
|
|
||
---|---|---|---|---|
Dependent | Independent | |||
Postoperative VA | Age | 0.041 | 0.784 | |
Duration of macular detachment | 0.869 | 0.024 | ||
Preoperative VA | 0.188 | 0.249 | ||
Preoperative OCT findings | RD height | 0.212 | 0.203 | |
Total macular area | −0.511 | 0.041 | ||
Outer layer macular area | 0.334 | 0.180 | ||
Middle layer macular area | 0.267 | 0.156 |
VA = visual acuity, OCT = optical coherent tomography, RD = retinal detachment, and
Correlation of preoperative clinical findings to 6-month postoperative best-corrected visual acuity (BCVA). There was a positive correlation between preoperative and 6-month postoperative BCVA ((a);
Images of eyes representing good and poor visual outcomes after surgery for macula-off RRD are shown in Figure
Representative eyes with good and poor visual outcomes after surgery for macula-off rhegmatogenous retinal detachment. (a) 65-year-old woman (preoperative decimal visual acuity: 0.7) with a good visual outcome (postoperative decimal visual acuity: 1.2). (b) 60-year-old woman (preoperative decimal visual acuity: 0.3) with a poor visual outcome (postoperative decimal visual acuity: 0.3). Preoperative photographs of the fundus, preoperative optical coherence tomography (OCT) images, and postoperative OCT images are shown on the left, center, and right, respectively. Preoperative foveal area was relatively thinner in the case with a poor outcome than in the case with a good outcome.
We set out to evaluate the potential of newly developed OCT parameters to predict postoperative BCVA in macula-off RRD eyes. We found that 6-month postoperative BCVA was significantly correlated with RD height at the fovea and with the total and inner cross-sectional area of the macular layer within 2 mm of the fovea, as well as with preoperative BCVA. Furthermore, multiple regression analysis revealed that the duration of the macular detachment and the total cross-sectional macular area were independent factors predicting 6-month postoperative BCVA.
Surgeons cannot easily predict postoperative visual outcomes in cases of RRD, and even after successful RRD surgery, many patients only regain a poor level of postoperative visual function. This often causes patients to experience preoperative anxiety. Our results confirmed existing data showing that the duration of the macular detachment was associated with postoperative visual outcome, although the usefulness of this parameter is limited, because it depends on the memory of the patient and their cooperation and therefore cannot always be reliably known [
The pathogenesis of poor visual outcomes in RRD is related to photoreceptor cell death [
This study showed that RD height at the fovea, a measurement parameter used in a number of earlier studies, was associated with postoperative BCVA in a single regression analysis, confirming earlier reports [
Limitations of this study included a relatively short follow-up time of 6 months, a relatively small sample size (about 60), and the omission of postoperative functional findings from standard automated perimetry or focal electroretinography. Additionally, although bullous RRD eyes are often seen in the clinic, the method described here cannot be used to predict postoperative outcomes in cases when OCT scans do not show the macula. Furthermore, to prevent bias in the results, it was necessary to omit the inner macular layer in the cross-sectional image from our multiple regression analysis, because the total and inner layer values were not independent, both being OCT findings and being closely correlated with 6-month postoperative BCVA. At first, we hypothesized that visual outcome would be associated with the area of the outer macular layer, as this contains the outer nuclear layer and the photoreceptor cells, but this hypothesis was not borne out by the data. It is unclear why this was so, but it may have been related to the susceptibility of the outer layer to intraretinal edema or undulation, which makes it difficult to obtain accurate measurements. Nevertheless, we believe our results show that simple OCT measurement of total cross-sectional area within 2 mm of the fovea is currently the most useful and objective way to predict postoperative visual outcomes in eyes with macula-off RRD, at least until technology to quickly evaluate macular volume in three dimensions becomes available for use in eyes with detached maculas. The usefulness of the measurement method described here would also be greatly enhanced by an OCT program to automatically measure cross-sectional macular area in eyes with macula-off RRD.
In conclusion, OCT measurement of preoperative total cross-sectional area of the macular layer within 2 mm of the fovea is a useful and objective way to predict postoperative visual outcomes in eyes with macula-off RRD and was closely correlated with 6-month postoperative BCVA. Further investigation is needed to measure the macular volume and determine its relationship with visual outcomes, which could lead to the development of a new automatic OCT program.
The authors declare that there is no conflict of interests regarding the publication of this paper.
The principal investigator, Dr. Noriyuki Suzuki, and the coinvestigator, Dr. Naoko Aizawa, had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the analysis. Involved in the design and conduct of the study were Hiroshi Kunikata and Toru Nakazawa; collection, management, analysis, and interpretation of the data Noriyuki Suzuki, Hiroshi Kunikata, and Naoko Aizawa; drafting of the paper Hiroshi Kunikata; and review or approval of the paper Hiroshi Kunikata, Toshiaki Abe, and Toru Nakazawa. All authors read and approved the final paper.
This paper was supported in part by a JST grant from JSPS KAKENHI Grants-in-Aid for Scientific Research (B) (Toru Nakazawa 26293372), for Scientific Research (C) (Hiroshi Kunikata 26462629), and for Exploratory Research (Toru Nakazawa 26670751).