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ORIGINAL ARTICLE
Year : 2017  |  Volume : 10  |  Issue : 3  |  Page : 220-224  

Causes and management of small pupil in patients with cataract


Department of Ophthalmology, Ophthalmiatrion Athinon, Athens, Greece

Date of Web Publication5-Oct-2017

Correspondence Address:
Irini Chatziralli
28, Papanastasiou Street, Agios Dimitrios, 17342, Athens
Greece
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ojo.OJO_102_2016

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   Abstract 

BACKGROUND: The purpose of the study was to present the causes and management of small pupil (<6 mm) in Greek patients with cataract.
METHODS: About 1144 consecutive patients with cataract comprised the study group. The pupil size was measured after maximal dilation by means of Rosenbaum cards and Colvard pupillometer. Dilation regimen included phenylephrine 10%, tropicamide 1%, cyclopentolate 1%, and ketorolac trometamol 0.5% administered 3 times at 5 min intervals starting 1 h before surgery. The presence of possible risk factors for small pupil was recorded. The need of additional maneuvers and devices to dilate the pupil during cataract surgery was examined, and the complication rate in cases with small pupils was recorded.
RESULTS: Small pupil was observed in 78 out of 1144 eyes (6.8%, 95% confidence interval = 5.2%–8.8%). Nine eyes had pupil size <4 mm (0.78%) preoperatively. Six cases (0.52%) developed intraoperative pupillary miosis. The major cause of small pupil was pseudoexfoliation (PEX) in 47.4% (37/78) of patients. No significant associations were observed regarding age, gender, history of diabetes mellitus, the maturity of cataract, and phacodonesis. Techniques for small pupil management included pupil stretching in 14 cases (17.9%), use of iris hooks in 6 cases (7.7%), iris sphincter cuts in 2 cases (2.6%), and placement of a Malyugin Ring in 4 cases (5.1%). Seven eyes (9%) with small pupil had capsular rupture versus 16 eyes (1.5%) with normal dilation (P < 0.001).
CONCLUSIONS: Small pupil is not very common in Greek population, is mostly caused by PEX, and it is associated with increased complication rate.

Keywords: Cataract surgery, pseudoexfoliation, pupillary dilation


How to cite this article:
Halkiadakis I, Chatziralli I, Drakos E, Katzakis M, Skouriotis S, Patsea E, Mitropoulos P, Kandarakis A. Causes and management of small pupil in patients with cataract. Oman J Ophthalmol 2017;10:220-4

How to cite this URL:
Halkiadakis I, Chatziralli I, Drakos E, Katzakis M, Skouriotis S, Patsea E, Mitropoulos P, Kandarakis A. Causes and management of small pupil in patients with cataract. Oman J Ophthalmol [serial online] 2017 [cited 2019 May 24];10:220-4. Available from: http://www.ojoonline.org/text.asp?2017/10/3/220/215986


   Introduction Top


Cataract surgery is one of the most common surgical procedures worldwide.[1],[2] Phacoemulsification and recent advances in cataract surgery techniques led to improved postoperative outcomes, as well as to reduced intra- and post-operative complications, even in difficult cases.[2],[3] Phacoemulsification through small pupil, however, remains challenging for the surgeon and is considered to be associated with more complications.[3],[4],[5],[6] Many reasons explain the increased risk of complication in eyes with small pupil. Loose zonules and hard nuclei are not always visible through small pupils, and the surgeon is not prepared to cope with these situations. Furthermore, maneuvering in the capsular bag behind the iris in spaces that cannot be seen by the surgeon should also explain the increased risk of complications. The pupil may fail to dilate in conditions such as pseudoexfoliation (PEX), after long-term miotic treatment for glaucoma, after trauma, or surgery.[6] Recently, Intraoperative floppy iris syndrome (IFIS) characterized by poor pupil dilation and a triad of signs that occur during cataract surgery, i.e., iris billowing, iris prolapse, and progressive intraoperative miosis, has been described.[7],[8] IFIS has been associated with systemic administration of tamsulosin and other α-1-adrenergic receptor antagonists such as alfuzosin, doxazosin, and terazosin.[7],[8]

A great number of maneuvers and instruments have been described to manage small pupil including iris sutures, Healon 5, iris hooks, mechanical stretching, and ring expanders.[4],[9],[10],[11],[12],[13] Nevertheless, not many studies have examined the prevalence and the causes of inadequate pupillary dilation. In a prospective study involving 1880 consecutive cataract procedures performed by one surgeon, Gimbel found 30 eyes (1.6%) with small pupil (preoperative diameter of 4 mm or less).[9] In addition, in the prospective assessment of IFIS in 900 consecutive cataract surgeries, IFIS was diagnosed in 16 patients (2.2%).[7]

In light of the above, the purpose of the present study was to investigate the incidence of small pupil in Greek population with cataract and the possible risk factors associated with small pupil. Furthermore, we examined the need for additional maneuvers and devices to dilate the pupil and the complication rate in cases with small pupil.


   Methods Top


Participants of our prospective study were 1144 consecutive patients, who underwent routine cataract surgery from September 2011 to July 2012 at Specialized Eye Hospital “Ophthalmiatrion” Athinon. One eye of each patient was included in the present study. If both eyes were eligible, the eye with the smallest pupil was included in the study.

Pupil dilation and measurement technique

All patients were fully dilated preoperatively. Dilation included phenylephrine 5% (Phenylephrine 5%, Cooper Athens, Greece), tropicamide 1% (Tropical, Demo SA, Athens, Greece), cyclopentolate 1% (Cyclogyl, Alcon, Athens, Greece), and ketorolac trometamol 0.5% (Acular, Allergan, Athens, Greece) administered 3 times at 5 min intervals starting 1 h before surgery. Of note, anti-inflammatory drops were also used 4 times/day, 1 day preoperatively. This was routinely supplemented with phenylephrine 10% (Phenylephrine 10%, Cooper Athens, Greece) if the pupil did not dilate well (>6 mm) before surgery; therefore, all small pupil cases received phenylephrine 10% preoperatively.

Pupil size was measured preoperatively after full dilation by means of Rosenbaum cards in standardized mesopic luminance. In cases of small pupils <6 mm, a more detailed measurement with Colvard pupillometer (Oasis Medical) was performed, and this measurement was recorded.[14] Pupil size was evaluated with a 1.0 mm interval scale at the nearest half millimeter. Pupil size characterized as normal (more than 6 mm), small (4–6 mm), or very small (<4 mm).

Phacoemulsification technique

All surgeries were performed in “Ophthalmiatrion” Athinon Eye hospital by or under the direct supervision of an experienced surgeon. A 2.4–2.7 mm clear corneal incision was used in all patients. Sodium hyaluronate 3%–chondroitin sulfate 4% (Viscoat) was the ophthalmic viscoelastic device used in all cases. Fortified balanced salt solution (Plus) with 0.5 ml of 1:1000 adrenaline in 500 ml was used as the irrigating solution in small pupil cases. Furthermore, in cases with small pupils, different mechanical pupil dilatation methods were used according to surgeon's preference. Cases with normal preoperative pupil measurement, in which the surgeon used mechanical dilation method due to intraoperative pupillary constriction were recorded. Following capsulorhexis and hydrodissection, standard phacoemulsification was performed using Infiniti Vision System platform (Alcon, Fort Worth, TX, USA). The vertical phaco-chop or divide-and-conquer technique was used depending on nuclear density and surgeon's preference.

For statistical purposes, pupil size <6 mm was considered as one category. The following data were evaluated as possible risk factors for small pupil: Sociodemographic features (age and gender), ophthalmological conditions (PEX, miotic drops use, white cataract, phacodonesis, and previous uveitis), clinical data (diabetes mellitus), and current α-blockers use (tamsulosin, alfuzosin, terazosin, and doxazosin). The information about medications was gathered by the medical health records of patients and was confirmed by the patients as well. The surgical technique including additional maneuvers as well as potential complications (posterior capsular rupture, zonule dialysis, vitreous loss, and drop of nucleus) was also recorded.

This study is in accordance with the Declaration of Helsinki and has been approved by the local Institutional Review Board. Written informed consent was obtained from all patients. The authors declare no conflict of interest.

Statistical analysis

With respect to the statistical analysis, small pupil was treated as a dichotomous variable (0 = no small pupil and 1 = small pupil). The association between small pupil and possible risk factors (ophthalmological conditions, sociodemographic features, current α-blockers use, and diabetes mellitus) entailed two steps: (i) Univariate analysis and (ii) multivariate analysis (multivariate logistic regression). At the univariate analysis, the associations between small pupil and possible risk factors were evaluated with Pearson's Chi-square test, Fisher's exact test, and Mann–Whitney–Wilcoxon test for independent samples, as appropriate. At the multivariate logistic regression, small pupil was treated as the dependent variable, and the variables found significant at the univariate analysis were examined as independent variables. P < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS 17.0 (SPSS, Inc., Chicago, IL, USA).


   Results Top


The present study included 519 male patients and 625 female patients with a mean age of 74.1 ± 7.9 years. Small pupil was observed in 78 out of 1144 eyes (6.8%, 95% confidence interval [CI]: 5.2%–8.8%). Among 78 cases, 63 pertained to small pupil among 4–6 mm and 9 to small pupil <4 mm (0.78%) preoperatively. In six cases (0.52%), small pupil was observed during the operation. Among 78 cases with small pupil, 37 eyes (47.4%) had PEX, 4 (5.1%) eyes had uveitis with posterior synechiae, 5 (6.4%) patients reported the current α-blocker use, 2 eyes (2.6%) had previous trabeculectomies for open angle glaucoma, 1 (1.3%) patient reported pilocarpine use in the past, and 1 (1.3%) prior trauma.

[Table 1] presents the features of the study population. PEX, previous uveitis with posterior synechiae, and current α-blocker use were associated with small pupil at the univariate analysis. On the other hand, no significant associations were observed regarding age, gender, diabetes mellitus, the maturity of cataract, and phacodonesis. [Table 2] presents the results of the multivariate analysis. PEX was independently associated with pre- or intraoperatively small pupil, as reflected upon the mutually adjusted odd ratios. It is worth mentioning that previous uveitis and current α-blocker use lost their significance at the multivariate approach.
Table 1: The features of the study population

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Table 2: Results of the multivariate logistic regression analysis (with the respective odds ratios [mutually adjusted])

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As far as the management of small pupil is concerned in our sample, surgically management maneuvers were required in 26 eyes with small pupil (33.3%) and included pupil stretching in 14 cases (17.9%), use of iris hooks in 6 cases (7.7%), iris sphincter cuts in 2 cases (2.6%), and Malyugin ring® (Microsurgical Technology Redmond, WA, USA) in 4 cases (5.1%).

There was a statistically significant difference in complication rate between eyes with small pupil and normal eyes (P < 0.001, Fisher's exact test). Specifically, 7 eyes with small pupil suffered posterior capsular rupture (9.0%, 95% CI: 7.2%–9.7%), and in one, there was drop of the nucleus versus 16 cases with normal pupil, which suffered posterior capsule rupture (1.5%, 95% CI: 0.9%–1.9%).


   Discussion Top


The present study investigated the prevalence and causes of inadequate pupillary dilation in the Greek population with cataract. Studies that are conducted to estimate the prevalence of cataract or macular degeneration in a population require the pupil of the eye be dilated to an optimal size of at least 6 mm for observation and photography.[15] Furthermore, a pupil size large enough for adequate capsulorhexis is considered large enough to perform phacoemulsification. A 5.5–6.0-mm capsulorhexis is adequate for routine cases.[11] Bearing this in mind, we counted all cases with <6 mm pupillary dilation as small pupils.

According to the results of the present study, sufficient pupillary dilation was not accomplished in 6.3% of eyes. Akman et al. reported that eyes in which pupil size >3.5 mm could not be achieved with pharmacological dilation may require mechanical dilation during cataract surgery.[11] According to the present study, 9 eyes (0.78%) had pupil size <4 mm preoperatively, whereas 26 eyes (2.27%) in total required various methods of mechanical pupillary dilation. Specifically, iris retractor hooks and Malyugin Ring are the most time-consuming techniques but may stabilize better the pupil size throughout the surgery, causing moderate iris trauma and minimal risk of complications.[11] The percentages of eyes with small pupil reported in the present study compare well with the previously reported percentage of 1.6% by Gimbel although the patient population was different.[9]

The most common etiology of inadequate pupillary dilation was predictably PEX, as it was identified in almost 50% of eyes with small pupil. In fact, in Greece, the prevalence of PEX is relatively high, maybe due to genetic reasons, since various polymorphisms were found to be associated with PEX in Greek population although environmental factors may also be implicated.[16],[17],[18] However, inadequate pupil dilation was not very common in our patient population with PEX, as it occurred in only one-quarter of the patients. Contrary to the present study, Drolsum et al. reported that small pupil occurred in 47% of their patient population with PEX and cataract.[19] Nevertheless, they did not specify what size of pupil they count as “small pupil” in their study.

Although 6.4% of patients with small pupil used α-blockers preoperatively, statistical analysis indicated that α-blocker use was not associated with small pupil in multivariate analysis. This finding is not surprising since the degree of IFIS syndrome may vary among patients, among specific medication, and even among eyes of the same patient. Manvikar and Allen reported that only 9% of eyes of patients receiving tamsulosin had small pupil preoperatively.[20]

The present study verified results of previous studies that small pupil is a risk factor for complications.[5],[6] Posterior capsule rupture was almost 6 times more common in eyes with inadequate pupillary dilation. Results of the present study indicate that there is not associated pathology such as lens subluxation coexistent with small pupil. Thus, increase of complications stems probably from difficulty in surgical maneuvering.

Surprisingly, no identifiable cause could be established for almost one-third of cases with small pupil. Two possible reasons may account for this. Some of the eyes may suffer subclinical PEX that was not evident even in the most thorough clinical evaluation.[21],[22] Second, there are several case reports of other medications apart from α-blockers causing IFIS and possibly small pupil. Recently, antidepressant and antipsychotic drugs such as mianserin, chlorpromazine, and imipramine have also been reported to be associated with this syndrome.[23] Possibly, we are still not aware of all the causations of the syndrome.

The major limitation of the present study is that it refers to the Greek patient population. In Greece, there is a high prevalence of PEX syndrome ranging between 11.5% and 16% depending on the area.[24],[25] The prevalence of PEX ranges from 20% to 25% in the Scandinavian countries to <1% in the Chinese and Japanese.[26],[27],[28] The difference in prevalence of PEX among various populations may be a burden to the generalization of the results of the present study.


   Conclusions Top


Small pupil is not very common in Greek population and is mostly associated with PEX. Less than 3% of patients with cataract required additional surgical devices to dilate the pupil intraoperatively. However, inadequate pupil dilation is a risk factor for complications and demand careful surgical planning. Therefore, surgeons should be aware of various causes of small pupil so as to identify “vulnerable” and high-risk cases preoperatively, during the slit-lamp examination and taking into account the medical and ophthalmological history of the patient.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

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Katsimpris JM, Petropoulos IK, Apostolakis K, Feretis D. Comparing phacoemulsification and extracapsular cataract extraction in eyes with pseudoexfoliation syndrome, small pupil, and phacodonesis. Klin Monbl Augenheilkd 2004;221:328-33.  Back to cited text no. 3
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Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin. J Cataract Refract Surg 2005;31:664-73.  Back to cited text no. 7
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Chang DF, Braga-Mele R, Mamalis N, Masket S, Miller KM, Nichamin LD, et al. ASCRS white paper: Clinical review of intraoperative floppy-iris syndrome. J Cataract Refract Surg 2008;34:2153-62.  Back to cited text no. 8
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Founti P, Haidich AB, Chatzikyriakidou A, Salonikiou A, Anastasopoulos E, Pappas T, et al. Ethnicity-based differences in the association of LOXL1 polymorphisms with pseudoexfoliation/pseudoexfoliative glaucoma: A meta-analysis. Ann Hum Genet 2015;79:431-50.  Back to cited text no. 17
    
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Mardin CY, Schlötzer-Schrehardt U, Naumann GO. Early diagnosis of pseudoexfoliation syndrome. A clinical electron microscopy correlation of the central, anterior lens capsule. Klin Monbl Augenheilkd 1997;211:296-300.  Back to cited text no. 21
    
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Forsman E, Cantor RM, Lu A, Eriksson A, Fellman J, Järvelä I, et al. Exfoliation syndrome: Prevalence and inheritance in a subisolate of the Finnish population. Acta Ophthalmol Scand 2007;85:500-7.  Back to cited text no. 27
    
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    Tables

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