Small pupil is a well-known risk factor associated with numerous complications during and after cataract surgery. Inadequate pre-operative mydriasis or intra-operative miosis results in iris trauma and photophobia.[1,2] There are numerous factors leading to poor pupil dilation, including systemic diseases, intake of some pharmacological agents, and local co-morbidities [glaucoma, ocular trauma, previous ocular surgery, uveitis, and floppy iris syndrome (FIS)]. These factors add on to the most significant cataract surgery complications such as vitreous loss, anterior capsular tear, increased inflammation, an irregular pupil shape, posterior capsular rupture (PCR), and retained lens material.[1]
The various available methods of managing small pupil include pharmacologic agents such as the use of intracameral lidocaine, epinephrine in balanced salt solution (BSS; Alcon Laboratories, Inc.), and intracameral solutions such as shugarcaine [4% unpreserved lidocaine diluted 1:3 with BSS Plus (Alcon Laboratories, Inc.)] or intracameral phenocaine by ENTOD [phenylepherine (0.31%) + lidocaine 1% + tropicamide 0.02%],[2] which are all tools at the cataract surgeon’s disposal. Visco-mydriasis with a visco-dispersive agent of a heavy molecular weight such as Healon GV or Healon5 (both from Abbott Medical Optics Inc.) can also be helpful in breaking mild to moderate synechial closure.[3]
When a more aggressive approach is required to open an obstinate pupil, incisional or stretching strategies (Y-shaped stretcher) may be helpful. In cases of intra-operative FIS, iris retention is the technique of choice to avoid peri-operative miosis. Iris hooks or expansion devices such as the Graether Pupil Expanding System (EagleVision), Beehler Pupil Dilator (Moria SA), and Malyugin Ring (MicroSurgical Technology) can open the pupil and be used alone or in combination with one another.[4]
In this communication, we describe a novel instrument designed by the author that combines two mechanisms, 1) iris stretching rod on its one side and 2) a curved chopper on the other end. We describe our initial experience with this instrument across a spectrum of small pupil management and eyes with intra-operative miosis.
Innovation
Description of the instrument
The instrument is made of stainless steel; at one end is a straight rod, and the other end has a curved chopper [Fig. 1] with a tip dimension of 0.8 mm which allows for easy entry through the side ports. In scenarios wherein we have moderately dilated pupil (5 mm) with any amount of iris billowing or miosis, it allows for simultaneous stretching of the floppy iris, thus enabling the phaco probe to hold a nuclear fragment and emulsifying the nucleus, whereas the curved chopper allows for easy nucleus chopping and allowing us to manage the small pupil and nucleus emulsification without the use of any pupil-expanding devices.
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Figure 1: Stainless-steel chopper with a rod on one side and a curved chopper on the other side
Clinical applications
- Intra-operative miosis because of FIS: Intra-operative FIS is classified upon the presence of floppy iris stroma, which billows and ripples responding to phaco fluidics with progressive intra-operative miosis, independent of the use of mydriatic agents, and the iris stroma’s tendency to prolapse through the incisions.[1] The Y-shaped chopper allows stretching the floppy iris to the periphery and preventing iris plugging in the phaco probe during aspiration and concomitantly performing nuclear fragmentation without risking anterior capsular tears or PCR and thus prevents the prolapse of the iris through the side ports or main wound [Video 1].
- Small Pupil management: The Y-shaped chopper design allows for both capsular and iris stretching to enable the phacoemulsification in eyes in small pupils (<5 mm), allowing easy sculpting, nuclear fragmentation, and chopping of the nucleus fragments into smaller pieces. The rotation of the nucleus and epinuclear plate can also be achieved with ease, thus allowing the surgeon to sail through the cataract surgery without the use of pupil-expanding devices which can cause sphincter damage and post-operative photophobia to the patient [Video 2].
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Discussion
Successful surgical outcomes have been achieved with both mechanical iris dilation and iris retention devices, and these devices add to overall surgical cost and generally require more time in the operating theater than a mechanical pupillary stretch.[5]
One of the most important inventions in the history of mechanical pupil expansion was introduction of the iris hooks. Since the very first reports, the technique gained wide popularity all over the world. The advantages of this technique include ease of manipulations and wide availability of the hooks manufactured in different sizes, materials, and designs. However, there are chances of iris sphincter tears and risk of bleeding.[1] It is generally recommended not to extend the pupil over 5.0 mm in size to decrease the chances of iris tissue over-stretching and in turn producing irregular and atonic pupils post-operatively, which can lead to post-operative photophobia and Haloes .[1]
Pupil stretching till date has been performed with the help of two instruments (spatulas, Kuglen hook, or similar) introduced through paracentesis incisions located contralateral to each other. However, pupillary stretching maneuvers are more traumatic to the iris and also possibly to the corneal endothelium, but this does not appear to detract from the surgical outcomes.[6]
The major drawback is that intra-operatively, the iris can get pulled into the phaco probe and in the corneal wounds, which makes it difficult to perform nuclear fragmentation and simultaneously salvage the iris. This problem gets alleviated with our Y-shaper chopper which allows us to manage the FIS and perform nuclear emulsification. In our initial experience, we have not observed any loss of iris tone or permanent damage or any patient complaining of post-operative photophobia.
Conclusion
Significant variations in the ocular and systemic co-morbidities require the whole spectrum of pharmacological and surgical strategies to be in the armamentarium of the modern cataract surgeon. The easiness of manipulations and the final results vary significantly with different devices. Iris hooks and Malyugin Ring are the current standard of care for intra-operative mechanical pupil expansion in patients not responding to the pharmacological protocols. Some of these methods are associated with bleeding, loss of iris sphincter function, and an abnormal pupil shape post-operatively. The author’s initial experience with the Y-shaper and chopper minimizes the risk of intra-operative complications, yet enabling surgeons to aim at similar surgical outcomes. Further studies are needed to compare the various available techniques and assess the learning curve associated with this instrument.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgement
We acknowledge contribution of Mr. Mateen Amin of Epsilon in making prototypes of instrument.
References
1. Malyugin B. Cataract surgery in small pupils. Indian J Ophthalmol 2017;65:1323–8.
2. Joshi RS. Phacoemulsification without preoperative mydriasis in patients with age-related cataract associated with type 2 diabetes. Clin Ophthalmol (Auckland, NZ) 2016;10:2427–32.
3. Eong KG. The complicated cataract: The Massachusetts eye and ear infirmary phacoemulsification practice handbook. edited by Roberto Pineda II, Alejandro Espaillat, Victor L. Perez, and Susannah G. Rowe. SLACK, 2001. 176 pages, illustrated, soft cover. $49.00. Am J Ophthalmol 2002;133:431.
4. Novak J. Flexible iris hooks for phacoemulsification. J Cataract Refract Surg 1997;23:828–31.
5. Wilczynski M, Wierzchowski T, Synder A, Omulecki W. Results of phacoemulsification with Malyugin Ring in comparison with manual iris stretching with hooks in eyes with narrow pupil. Eur J Ophthalmol 2013;23:196–201.
6. Masket S. Avoiding complications associated with iris retractor use in
small pupil cataract extraction. J Cataract Refract Surg 1996;22:168–71.
