|Year : 2017 | Volume
| Issue : 3 | Page : 111-114
Effectiveness of scleral decompression procedures for preventing choroidal effusion in nanophthalmic eyes: A retrospective review
Parveen Rewri1, Nirha Chetan Rao2, Ronnie George2, Shantha Balekdaru2, Vijaya Lingam2
1 Jadhavbai Nathamal Singhvi Glaucoma Services, Sankara Nethralya, Chennai, Tamil Nadu; Department of Ophthalmology, Maharaja Agrasen Medical College, Agroha (Hissar), Haryana, India
2 Jadhavbai Nathamal Singhvi Glaucoma Services, Sankara Nethralya, Chennai, Tamil Nadu, India
|Date of Web Publication||11-Oct-2017|
Sankara Nethralaya, 18, College Road, Chennai - 600 006, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Purpose: The purpose of this study is to study role of prophylactic scleral decompression procedures in the prevention of choroidal effusion in nanophthalmos. Materials and Methods: Nanophthalmos was defined as eye with axial length (AL) (<20 mm), hyperopia (>+5.00 D) and scleral thickness (>1.7 mm). In a retrospective case series, we analyzed 21 eyes of 21 patients with nanophthalmos, who underwent cataract and/or glaucoma surgery with concurrent sclerotomy or sclerotomy with sclerectomy. Results: The mean age at the time of surgery was 51 ± 7 years. The mean AL was 17.18 ± 1.74 mm. Surgery-related complications were documented in 8 (38%) eyes. The prophylactic scleral decompression procedures did not offer protection against postoperative choroidal effusion (P = 0.6). On univariate logistic regression, preoperative intraocular pressure (P = 0.01) was significantly associated with postoperative complications. Conclusion: Prophylactic scleral decompression does not offer absolute protection against postoperative complications during cataract and/or glaucoma surgery in nanophthalmic eyes.
Keywords: Cataract, glaucoma, nanophthalmos, prophylactic scleral decompression procedures, sclerectomy, sclerotomy
|How to cite this article:|
Rewri P, Rao NC, George R, Balekdaru S, Lingam V. Effectiveness of scleral decompression procedures for preventing choroidal effusion in nanophthalmic eyes: A retrospective review. J Clin Ophthalmol Res 2017;5:111-4
|How to cite this URL:|
Rewri P, Rao NC, George R, Balekdaru S, Lingam V. Effectiveness of scleral decompression procedures for preventing choroidal effusion in nanophthalmic eyes: A retrospective review. J Clin Ophthalmol Res [serial online] 2017 [cited 2018 Mar 24];5:111-4. Available from: http://www.jcor.in/text.asp?2017/5/3/111/216433
Although there is no consensus on the definition of nanophthalmos, the condition encompasses smaller eyes in the absence of any other malformations. Most of the literature describes it on the basis of axial length (AL), the upper limit being usually of <20 mm. The smaller eye results from the developmental arrest of globe after the closure of embryonic fissure; and characterized by certain salient features such as high hyperopia, shorter than average AL, shallow anterior chamber; high lens: eye volume ratio, thickened choroid, and sclera.,,,,,, These biometric and structural features make the eye prone for many spontaneous and/or surgical complications., Performing surgeries in short eyes poses a challenge; and many intra- and post-operative complications have been described, including uveal effusion and serous retinal detachment (RD) with sudden decrease in intraocular pressure (IOP).,,, Prophylactic scleral decompression procedures have been recommended to prevent such complications.,,, In recent time with advent of surgical techniques better surgical outcomes also have been reported without prophylactic decompression procedures.,,
The study was designed to know the efficacy of prophylactic scleral decompression, namely sclerotomy or sclerotomy with sclerectomy, in the prevention of postoperative choroidal effusion in nanophthalmic eyes. We also studied the relationship between the occurrence of postoperative complications and ocular biometric parameters.
| Materials and Methods|| |
This was a retrospective case series approved by the Institutional Ethics Committee. The case records of patients with nanophthalmos who underwent concurrent prophylactic sclerotomy or sclerotomy with sclerectomy during cataract and/or glaucoma surgery, from 2000 to 2010 were studied. The case charts were identified by searching the database using the electronic medical record system of the institute. Nanophthalmic eye was defined as an eye with AL <20 mm with hyperopic refraction of +5.00 or more diopter and scleral thickness of 1.7 mm or more., Eyes with postoperative follow-up of <4 weeks were not included in the study.
Information retrieved from the charts included-demographics, preoperative refractive error, pre and postoperative best-corrected visual acuity (BCVA) and IOP, gonioscopy findings, and retinal and optic disc findings. Visual acuity (VA) was documented as Snellen fraction More Detailss and was converted to the log of minimum angle of resolution (log MAR) value of acuity. The A-scan ultrasonography provided the anterior chamber depth (ACD), lens thickness (LT) and AL measurements. The LT and AL were used to calculate the LT/AL ratio (LAR). The B-scan ultrasonography data was used to obtain scleral thickness and to evaluate the presence of uveal effusions. Intraoperative data collection included the type of surgery, type of prophylactic scleral decompression procedure; intraoperative complications, if any, and their management. Postoperative observations such as IOP, BCVA, postoperative complications, and additional interventions required were noted. In case of bilateral surgery, the eye that underwent surgical intervention first was included.
The choice and number of sites for prophylactic scleral decompression procedures was based on surgeon's discretion. The decompression procedure was done during the same sitting before the intended surgical procedure for cataract and/or glaucoma. Sclerotomy was created beyond pars plana and the center of radial incision was 5 mm from limbus. In sclerectomy with sclerotomy partial thickness sclera was removed in quadrant(s) between the recti and a V-shaped sclerotomy was created in the bed. The purpose of sclerotomy was to allow regression of any intraoperative choroidal effusion. The phacoemulsification with intraocular lens (IOL) implantation was standard procedure for cataract surgery. Trabeculectomy was done for IOP control in eyes with glaucoma. Single site IOL implantation and trabeculectomy in eyes requiring combined procedure was done. Postoperative regimen included topical steroids in weekly tapering fashion for 4–6 weeks on the discretion of operating surgeon.
We analyzed the data for the effectiveness of prophylactic procedures, either sclerotomy or sclerotomy with sclerectomy, in preventing choroidal effusion and association of postoperative complications with biometry variables. Data were entered into Excel spreadsheet (Microsoft Corp, USA) and statistical analysis was done using SPSS software (version 20.0, SPSS, Inc.) (Armonk, NY, IBM Corp). Comparison of continuous variables pre- and post-operatively was done using paired t-test and Wilcoxon-Signed rank test. The Fisher exact test was used for analyzing contingency tables. Univariate and multivariate analysis was done for any associations. P < 0.05 was considered as statistical significance.
| Results|| |
Case charts of 21 eyes of 21 patients were reviewed. The demographics and ocular biometric data are summarized in [Table 1]. The mean log MAR VA equivalent was 1.5 ± 0.75. The mean IOP at presentation was 23.7 ± 13.0 mmHg. Average follow-up period was 62 weeks (range 4–391 weeks). The cataract surgery alone was done in 12 eyes (57%), combined cataract and trabeculectomy in 6 (29%) eyes, and trabeculectomy alone in 3 (14%) eyes.
|Table 1: Demographic and baseline ocular and biometric parameters of study cases|
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Sclerotomy was done in 15 (71%) eyes and sclerectomy with sclerotomy in 6 (29%) eyes along with cataract and/or glaucoma surgery. The number of quadrants used for seclerotomies included – one quadrant in 10 (48%) eyes, two quadrants in 8 (38%) eyes and four quadrants in 3 (14%) eyes.
Surgery-related complications were documented in 8 (38%) eyes [Table 2]. The median duration of postoperative complications was 4 (range 1–7) days. Two (17%) of the 12 eyes, which underwent cataract surgery had intraoperative posterior capsule tear. Postoperative complications developed following trabeculectomy in three eyes and in one eye each after cataract and combined procedure. Choroidal effusion complicated the postoperative period in 5 (24%) eyes including hemorrhagic effusion in one eye, despite prophylactic decompression procedures. In another two eyes, effusion was associated with serous RD. Choroidal effusion and serous RD responded to combined regimen of topical and systemic steroids in three eyes (60%). In one case, there was recurrence after initial management and surgical drainage was done. Hemorrhagic effusion was managed by surgical drainage.
|Table 2: Frequency of surgery related intra- and post-operative complications|
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Biometric and structural variables of the eyes developing postoperative complications were not significantly different from eyes without complications [Table 3]. Eyes with LAR above 0.28 were more likely to be associated with postoperative complications. Five eyes postoperatively developed choroidal effusion/serous RD, of these, four eyes had received sclerotomy and one eye sclerotomy with sclerectomy. The prophylactic decompression procedures did not offer statistically significant protection in preventing postoperative choroidal effusion (P = 0.62). The odds ratio of developing postoperative choroidal effusion and/or serous RD was 0.76 (95% confidence interval [CI] was 0.05–10). The overall risk of developing a postoperative effusion was 29% (95% CI: 14%–50%), and risk ratio was 0.83 (95% CI: 0.14–4.8). The odds of developing postoperative complications with sclerotomy alone were 1.81, compared to sclerotomy with sclerectomy.
|Table 3: Comparison of variables among eyes which developed postoperative complication viz. no complication|
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On univariate logistic regression preoperative IOP (P = 0.01), and LAR (P = 0.04) were significantly associated with probability of postoperative complication of choroidal effusion and/or serous detachment [Table 4], but preoperative IOP was only significant (P < 0.05) variable associated with postoperative complications in multivariate regression.
|Table 4: Variables tested for association with complications on univariate analysis|
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Postoperatively, the best-corrected log MAR VA at final follow-up was 1.0 ± 0.84, a significant (P = 0.04) improvement from preoperative VA (1.5 ± 0.75). Vision improved in 13 eyes (62%); remained stable in 5 (24%) and deteriorated in 3 (14%) eyes. Two eyes had vision deterioration due to corneal decompensation, and in one eye due to the development of epiretinal membrane. None of the eyes lost vision after surgery. The mean IOP at final follow-up was 14 ± 8.7 mmHg, and there was a 41% reduction (P = 0.05) over the preoperative IOP.
| Discussion|| |
In the original description, Duke-Elder defined pure microphthalmos (nanophthalmos) as eyes with AL of <18.5 with some typical ocular clinical characteristics. However, the AL criterion has been relaxed to above 20 mm in literature.,, Definition of nanophthalmos based on AL alone, in the absence of consensus, is too simplistic for clinical implications. In the present study, we defined nanophthalmos based on both ocular biometric and structural parameters. We included only one eye because similar surgical outcomes in bilateral cases may skew the results.
Nanophthalmic eyes are at high risk of sight-threatening complications due to biometric and structural characteristics.,,,,,,, In consensus with previous studies, shorter AL, smaller ACD, and thicker sclera were characteristics of eyes in our series. Nanophthalmic eyes typically have lens-to-globe volume ratio (LGVR) above 0.1, and it usually ranges between 0.2 and 0.4. However, we calculated LAR instead of LGVR as reported in the previous study. Calculation of ratio involving lengths (LAR) was more feasible compared to volume (LGVR) calculation, using retrospective data. However, relative importance of either of parameter would require prospective data comparison.
Surgical procedures in nanophthalmic eyes have been reported with diverse outcomes.,,,, In this series, we observed surgical complications (intra- or post-operative) in large number of nanophthalmic eyes despite prophylactic scleral decompression procedures. The rate of complications in our series is comparable to complication rates previously reported.,,, Contrary to this, there are some studies that have reported markedly favorable surgical outcomes in nanophthalmic eyes.,, The marked differences in reported surgical outcomes in nanophthalmic eyes arise due to lack of a consensus on a standard definition. Eyes with uneventful intra- and post-operative period had ALs from 19.5 to 20.30 mm in series reported by Wu et al. In series by Day et al. odds of complication were higher in eyes with ALs <20 mm, compared to those between 20 mm and 21 mm. In studies reporting safety of cataract surgery without prophylactic decompression procedures, the AL has been observed belonging to upper end of the nanophthalmos. The risk of complications seems to increase in eyes with smaller ALs.,,,
Intraoperative complications results from crowding of anterior segment structures. There is increased risk of intraoperative posterior capsule rupture on the one hand and postoperative corneal edema or de-compensation on the other hand., The proximity between the ultrasonic waves and endothelium might result in corneal complications.
Uveal effusion and serous RD are most important postoperative complications in nanophthalmic eyes. Our study results show that risk of postoperative choroidal effusion/serous RD was high despite prophylactic decompression procedures. In our series, IOP was significantly associated with postoperative complications compared to anatomical variables such as AL, LT or LAR. We hypothesis this is due to the fact that most of postoperative complications in nanopthalmic eyes results from alteration of ocular hemodynamics, and IOP being a physiological variable may be better predictor. Further, the risk reduction with prophylactic decompression procedures does not bear a straightforward relationship with AL. We assume these procedures works best within certain range of ocular biometrics. On one spectrum towards shorter eyes perhaps effectivity of these procedures is not absolute, and on other side of spectrum, these procedures are perhaps not required. We did not find a clear relation between biometric parameters and role of prophylactic scleral decompression procedures in reducing complication rate.
Other than being retrospective, the study has certain limitations. The study subgroups are smaller and cannot be compared for relative effectiveness of prophylactic decompression procedures. For the same reasons chances of complication(s) with cataract or glaucoma surgery could not be compared.
| Conclusion|| |
Surgical intervention for cataract and glaucoma in nanophthalmic eyes poses challenge. The prophylactic decompression procedure does not offer absolute protection from the postoperative choroidal effusion. However, these procedures may be considered in eyes on shorter side of spectrum of AL.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]