Anterior sclerotomy used for adequate haptic externalization in glued IOL surgery

The procedure provides adequate haptic length for scleral tuck, which results in better IOL stability.

Issue: August 25, 2015

ByAmar Agarwal, MS, FRCS, FRCOphth

ByPriya Narang, MS

IOL implantation is an essential step for visual rehabilitation in cataract surgery or in cases of secondary IOL placement. When the IOL is placed within a capsular bag that is supported by the zonules 360° during cataract surgery, the IOL is usually in an acceptable and relatively stable position. However, in the absence of a posterior capsular bag, alternative approaches to IOL placement will be necessary.

These alternatives include anterior chamber placement of an anterior chamber IOL, iris-sutured IOL, ciliary sulcus placement of a posterior chamber IOL, scleral-supported posterior chamber IOL that includes the use of sutures, or scleral pocket-supported glued IOL. When placing an IOL in the anterior chamber or ciliary sulcus, the overall IOL length and the relative dimensions of the anterior chamber and ciliary sulcus are important considerations for a stable IOL implantation. This is less critical with an iris-sutured IOL placement, but mechanical rubbing of the IOL haptic against the iris should be prevented in such cases. In a scleral-fixated posterior chamber IOL using sutures, the suture length can be adjusted to compensate for the required optimal placement.

When using a scleral pocket to tuck a secondary IOL, the total length of the externalized haptic becomes important for long-term stability. Because the haptic length is fixed in the chosen IOL, the overall dimensions of the anterior segment of the eye and the relative haptic exit point from the interior of the eye will determine the total length of the externalized haptic that can then be tucked within the scleral pocket. Shorter length of an externalized haptic can have a negative impact on IOL stability postoperatively.

In this column, Drs. Agarwal and Narang describes a useful technique to compensate for variations in the anterior segment size of the human eye and obtain adequate length of the externalized IOL haptic for a scleral pocket-housed glued IOL.

Thomas “TJ” John, MD
OSN Surgical Maneuvers Editor

The importance of adequate haptic tuck into the scleral pocket cannot be overemphasized in glue-assisted intrascleral haptic fixation. Inadequate tuck may lead to slippage of the haptic and eventually a decentered or subluxated IOL. The tendency for limited haptic exteriorization is greater in large eyes with a greater white-to-white diameter. In such eyes, the surgeon can proceed with anterior sclerotomy first, and we call it primary anterior sclerotomy. Anterior sclerotomy can be performed as a secondary procedure either intraoperatively or postoperatively after inadequate haptic exteriorization due to any cause ranging from haptic break to large eyes with greater white-to-white diameter or from a subluxated/decentered IOL to a previously posteriorly placed sclerotomy that shifts the plane of IOL quite posteriorly, leading to short or inadequate haptic exteriorization.

Surgical technique

In a routine glued IOL surgery, the sclerotomy is placed 1 mm to 1.5 mm away from the limbus beneath the scleral flaps (Figure 1). For cases that necessitate anterior sclerotomy (Figure 2), the incision is placed at 0.5 mm away from the limbus (Figure 3). The 20-gauge needle is directed more vertically, and once it crosses the iris plane, it is directed toward the vitreous cavity. This ensures entry of the needle beneath the iris plane, which serves as a subsequent path for haptic externalization.

In cases in which anterior sclerotomy is performed secondarily to inadequate haptic exteriorization (Figure 2), care and caution have to be exerted when choosing the site for sclerotomy because placing an anterior sclerotomy close to the previous site may lead to a big entry that may leak subsequently. To avert this, the surgeon should take care to leave an adequate bridge of tissue between the two sites.

Figure 1. Sclerotomy being made with a 20-gauge needle beneath the scleral flap.

Figure 2. Note that limited haptic is available for a scleral tuck.

Figure 3. Anterior sclerotomy being made with a 20-gauge needle in front of the previously existing sclerotomy.

Figure 4. The tip of the haptic is grasped to re-internalize it.

PAGE BREAK

The haptic is re-internalized into the eye from the posterior sclerotomy site (Figures 4 and 5) and then re-externalized from the new anterior sclerotomy site with the help of the handshake technique (Figure 6). After the maneuver, it is observed that the amount of haptic externalized is much more than before due to the forward shift of the IOL plane (Figure 7). The posterior sclerotomy site is often sutured to avoid any inadvertent chances of hypotony in the postoperative period (Figure 8).

Discussion

Every surgical procedure has a set of advantages and disadvantages. The disadvantage with anterior sclerotomy is increased chances of iris root disinsertion that may require pupilloplasty as a surgical tool for correction. Hyphema may also occur, but often this is a self-limiting condition. The advantage with the procedure is that it provides adequate haptic length for scleral tuck, which eventually translates into better IOL stability with eventually no chances of subluxation/decentration of the IOL in the postoperative period. This specific advantage outweighs all the disadvantages and hence is advocated.

Performing anterior sclerotomy shifts the IOL plane more anteriorly, thereby allowing greater haptic length exteriorization. Intraoperatively, whenever a surgeon has inadequate haptic length, the options are to tuck the haptic at the base of the scleral flap rather than at the edge of the base of the flap bed; explant the IOL and redo the procedure with a new IOL; or perform an anterior sclerotomy followed by re-internalization and re-externalization of the haptic with the help of the handshake technique through the new anterior site that is created.

Figure 5. The re-internalized haptic is transferred from the right hand to the left hand with the handshake technique.

Figure 6. The haptic is then re-externalized from the anterior sclerotomy.

Figure 7. Note the extra length of haptic that is available for a scleral tuck.

Figure 8. Posterior sclerotomy being sutured to prevent postoperative hypotony.

To conclude, anterior sclerotomy serves as an effective method to overcome short haptic length in glued IOL surgery, and it often comes as an effective rescue measure to overcome the complex scenario.

References:
Ashok KD, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2014.05.039.
Jacob S, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2014.12.035.
Kara N. J Refract Surg. 2015;doi:10.3928/1081597X-20150623-08.
Kumar DA, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2013.03.004.
McKee Y, et al. J Cataract Refract Surg. 2014;doi:10.1016/j.jcrs.2014.04.027.
Narang P. J Cataract Refract Surg. 2013;doi:10.1016/j.jcrs.2012.11.001.
Narang P, et al. Indian J Ophthalmol. 2013;doi:10.4103/0301-4738.112160.

For more information:
Amar Agarwal, MS, FRCS, FRCOphth, can be reached at Dr. Agarwal’s Eye Hospital, 19 Cathedral Road, Chennai 600086, India; email: dragarwal@vsnl.com.
Priya Narang, MS, can be reached at Narang Eye Care and Laser Center, 2nd Floor, AEON Complex, Vijay Cross Roads, Ahmedabad, 9. Gujarat, India; email: narangpriya19@gmail.com.
Edited by Thomas “TJ” John, MD, a clinical associate professor at Loyola University at Chicago and in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. He can be reached at tjcornea@gmail.com.

Disclosure: Agarwal, Narang and John report no relevant financial disclosures.