|Year : 2017 | Volume
| Issue : 1 | Page : 28-30
Ocular surface changes after simultaneous cataract surgery and limbal relaxing incisions
Mohamed A Ali, Ahmed Shawkat Abdelhalim
Department of Ophthalmology, Faculty of Medicine, Minia University, Minia, Egypt
|Date of Submission||06-Mar-2017|
|Date of Acceptance||21-Mar-2017|
|Date of Web Publication||17-May-2017|
Mohamed A Ali
Department of Ophthalmology, Faculty of Medicine, Minia University, Minia, 61519
Source of Support: None, Conflict of Interest: None
Purpose The aim of this study was to assess time-course changes of the ocular surface after simultaneous phacoemulsification and limbal relaxing incisions (LRIs) in the early postoperative period.
Patients and methods We prospectively examined 35 eyes of 22 consecutive patients who underwent simultaneous cataract surgery with LRIs both preoperatively and postoperatively (1 week, 1 month, and 3 months). Ocular surface quality was assessed in terms of corneal sensitivity, tear break-up time (BUT), and tear production, both preoperatively and postoperatively. Corneal sensitivity was measured using the Cochet–Bonnet corneal aesthesiometer, and tear volume was determined using Schirmer’s I test.
Results Corneal sensitivity was 58.5±3.9 mm preoperatively and was 58.3±2.7, 58.9±2.5, and 59.8±0.6 mm at 1 week, 1 month, and 3 months postoperatively, respectively [analysis of variance (ANOVA), P=0.13]. The BUT was 9.7±5.6 s preoperatively and was 5.6±3.1, 5.9±4.7, and 4.5±2.6 s at 1 week, 1 month, and 3 months, postoperatively, respectively (ANOVA, P=0.002). Tear volume was 15.2±8.8 mm preoperatively and was 12.2±6.9, 12.5±7.3, and 11.8±8.0 mm at 1 week, 1 month, and 3 months postoperatively, respectively (ANOVA, P=0.26).
Conclusion Simultaneous phacoemulsification with LRIs induced a significant decrease in BUT postoperatively without significantly affecting tear volume or corneal sensitivity.
Keywords: Cochet–Bonnet aesthesiometer, corneal sensitivity, limbal relaxing incisions, ocular surface, Schirmer’s test, tear break-up time
|How to cite this article:|
Ali MA, Abdelhalim AS. Ocular surface changes after simultaneous cataract surgery and limbal relaxing incisions. J Egypt Ophthalmol Soc 2017;110:28-30
|How to cite this URL:|
Ali MA, Abdelhalim AS. Ocular surface changes after simultaneous cataract surgery and limbal relaxing incisions. J Egypt Ophthalmol Soc [serial online] 2017 [cited 2017 Sep 22];110:28-30. Available from: http://www.jeos.eg.net/text.asp?2017/110/1/28/206316
| Introduction|| |
Phacoemulsification with intraocular lens (IOL) implantation has been widely accepted as an effective means for the treatment of cataract. In addition, good postoperative uncorrected visual acuity is essential to minimize spectacle dependence and maximize subsequent patient satisfaction after this procedure. Although surgical techniques, biometry, and IOL power calculation formulas have largely improved in recent years, corneal astigmatism can be a source of the remaining refractive errors after cataract surgery. Limbal relaxing incisions (LRIs) were developed to reduce pre-existing corneal astigmatism during cataract surgery ,,,.
With simultaneous phacoemulsification and LRI procedures being incisional, it is possible that the postoperative ocular surface profile regarding tear production and corneal sensation may be compromised with time and affect patients’ quality of vision, and hence modifying their lifestyle. However, to our knowledge, the ocular surface parameters after simultaneous cataract surgery and LRIs have not been specifically studied before or published in the literature. Because of the prevalence of these combined surgical procedures, it is important to quantitatively and longitudinally assess ocular surface changes postoperatively.
The aim of this study was to longitudinally assess the changes in ocular surface parameters with time in eyes undergoing simultaneous phacoemulsification and LRI procedures.
| Patients and methods|| |
We prospectively examined 35 eyes of 22 consecutive patients − 12 males and 6 females − undergoing cataract surgery through a temporal 2.8-mm clear corneal incision performed simultaneously with LRIs. The sample size of this study provided 98.3% statistical power at the 5% level to detect a 1-s difference in tear break-up time (BUT), when the SD of the mean difference was 1 s. The present study was approved by the institutional review board of our institute (Faculty of Medicine, Research Ethics Committee) and followed the tenets of the Declaration of Helsinki. Informed consent was obtained from all patients after explaining the nature and possible consequences of the study.
[Table 1] shows patients’ preoperative demographic data.
To compensate for potential cyclotorsion, the horizontal axis was marked at the slit-lamp preoperatively while the patient was sitting. LRIs were made as two, paired, arcuate incisions using a guarded micrometer diamond blade set at 500 μm. The incisions were made in the steepest corneal axis at the limbus just anterior to the palisades of Vogt for correcting preoperative corneal astigmatism documented by corneal topography ( Atlas More Details-9000, Carl Zeiss Meditec, Germany). The incision length was 45–65° of the arc according to the modified Gills nomogram. The incisions were irrigated with a balanced salt solution. After LRIs were made, a standard cataract surgery was performed. Phacoemulsification technique consisted of a capsulorrhexis, nucleus, and cortex extraction and implantation of an acrylic IOL implant through a temporal 2.8-mm clear corneal incision. Postoperatively, topical antibiotics and steroids were administered four times daily for 1 month, after which the dose was gradually tapered.
We quantitatively assessed the values of corneal sensitivity, tear film BUT, and tear production, preoperatively and at 1 week, 1 month, and 3 months postoperatively. Corneal sensitivity was measured with the Cochet–Bonnet corneal aesthesiometer, and tear volume was determined with Schirmer’s test without using a topical anesthetic agent before the test.
All statistical analyses were performed using StatView software (version 5.0; SAS Institute Inc., NC, USA). Paired t-test was used to compare preoperative and postoperative values. Repeated measures analysis of variance (ANOVA) was used to evaluate the changes over time. A P value less than 0.05 was considered statistically significant.
| Results|| |
Corneal sensitivity was 58.5±3.9 mm preoperatively and was 58.3±2.7, 58.9±2.5, and 59.8±0.6 mm at 1 week, 1 month, and 3 months postoperatively, respectively (ANOVA, P=0.13). The BUT was 9.7±5.6 s preoperatively and was 5.6±3.1, 5.9±4.7, and 4.5±2.6 s at 1 week, 1 month, and 3 months postoperatively, respectively (ANOVA, P=0.002). Tear volume was 15.2±8.8 mm preoperatively and was 12.2±6.9, 12.5±7.3, and 11.8±8.0 mm at 1 week, 1 month, and 3 months postoperatively, respectively (ANOVA, P=0.26).
[Table 2] shows the 1-week, 1-month, and 3-month postoperative ocular surface changes compared with preoperative values after simultaneous phacoemulsification with IOL implantation and LRIs.
|Table 2 Time-course changes in ocular surface parameters after simultaneous phaco-emulsification and limbal relaxing incisions|
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Paired t-test was used to compare preoperative and 3-month postoperative values, and we found statistically significant differences regarding BUT (P<0.0001); however, there were no statistically significant differences in values regarding corneal sensitivity and Schirmer’s test (P=0.07 and 0.06, respectively).
To analyze the course of changes over time, we used the multiple comparison test, and it was found to be highly significant for BUT (ANOVA, P<0.0001) but not for tear volume production (ANOVA, P=0.07) or corneal sensitivity (ANOVA, P=0.17).
| Discussion|| |
Dry eye symptoms and corneal sensation reduction are common after all types of corneal incisional refractive surgeries. Dry eye symptoms could disturb daily life activities of patients who undergo such corneal incisional procedures. Such morbidities increase proportionately with the severity of symptoms .
To the best of our knowledge, ocular surface changes have been studied after corneal refractive surgery − namely, laser-assisted refractive procedures; however, ocular surface studies after LRIs have not been carried out before. Our study revealed that simultaneous cataract surgery with LRIs reduces the quality of the ocular surface in terms of reduced tear film BUT and tear volume production without largely affecting the corneal sensation.
The preponderance of literature supports the hypothesis that the most important factor in the pathophysiology of refractive surgery-induced dry eye and decreased corneal sensitivity is the transection of corneal nerves in the anterior third of the corneal stroma that occurs during surgeries .
Cutting of corneal nerves that occurs during refractive surgeries may subsequently result in suppression of tear secretion from the lacrimal gland, mucin expression on the corneal epithelium, and frequent blinking, because these homeostasis-maintaining behaviors are driven by a neuronal feedback loop that is mediated by corneal sensitivity ,.
Mian et al.  and Golas and Manche  reported that the tear secretion function was suppressed during the first 3 months following the surgical procedure and returned to normal levels by 6 months after surgery. Horwath-Winter et al.  reported that there were no significant changes in the Schirmer’s test results. In a comparative study, a postoperative reduction in central corneal sensitivity in patients who underwent SMILE and femto-LASIK procedures was reported as compared with their preoperative sensitivity measurements. In addition, it was noticed that there was a trend toward an increase in corneal sensitivity after surgery. Comparing both groups, it was found that the mean central corneal sensation in the SMILE group was greater than that in the femto-LASIK group at all postoperative time points, which indicated that impairment in corneal sensation was greater after the femto-LASIK procedure than after the SMILE procedure .
Wei et al.  found that corneal sensitivity after the SMILE surgery was better than that after the FS-LASIK surgery at all postoperative visits (1 week, 1 month, and 3 months). However, they found that, at 3 months after the SMILE surgery, corneal sensitivity had recovered to preoperative levels, which is in agreement with our current study .
In conclusion, the results of this study indicate that simultaneous LRI with cataract surgery could result in dry eye symptoms, tear film instability, and decreased corneal sensitivity. However, the short-term follow-up course of these changes with time revealed that they are temporary and may return to their preoperative levels within a short time. Limitations of the present study include the relatively small sample size, the uncontrolled nonrandomized design, and the relatively short follow-up time; hence, larger samples with a control group are recommended for future studies with a longer time of follow-up.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]