Anterior megalophthalmos: Is visual restoration possible?

We report two cases of anterior megalophthalmos with cataract. Both cases have megalocornea, cavernous anterior chamber, enlarged iris-lens diaphragm, and normal axial length. The vision was less due to cataract. To restore vision, phacoemulsification was performed in each eye in both cases. Intraoperatively, to overcome anatomical challenges, we made scleral tunnel incision, stained anterior capsule, and fixated intraocular lens (IOL) by different techniques. In thefirst case, IOL was fixated through the sclera, whereas in the second case, IOL stabilization was achieved by capturing the optic in anterior capsulorhexis margin and placing the haptics in sulcus. Successful vision was restored in both cases without pseudophacodonesis.

Introduction

A rare hereditary condition, anterior megalophthalmos, is featured by bilateral megalocornea and an enlargement of iris–lens complex.[1] It is associated with a constellation of ocular findings with cataract being the most frequent cause of visual impairment.[23] To overcome challenges, cataract extraction and intraocular lens (IOL) implantation needs special consideration. Different types of IOL and their technique of implantation have been described in literature.[12456] However, scleral-fixated IOL or optic-capture to anterior capsulorhexis has not been described till date, to the best of our knowledge. Herein, we report two techniques of posterior chamber IOL fixation in two cases of anterior megalophthalmos.

Case Reports

Case 1

A 45-year-old male presented with bilateral megalocornea (right eye: 14 mm and left eye: 15 mm) [Figure 1a], mosaic corneal dystrophy [Figure 2], hyperdeep anterior chambers (ACs) [Figure 3a], and cataract [Figure 2]. Initial examination showed best-corrected vision as light perception in the right eye and 3/60 in the left eye. AC depth, lens thickness, axial length, and keratometric readings on IOL Master 500 (Carl Zeiss, Meditec, Jena, Germany) were 4.72 mm, 5.83 mm, 24.54 mm, 41.67 at 19°/44.23 at 109° and 4.69 mm, 4.87 mm, 24.79 mm, 42.13 at 168°/43.83 at 78° in the right and left eye, respectively. Ultrasound biomicroscopy (UBM) showed increased iris–lens diaphragm [Figure 4]. Vitreous index (vitreous length/axial length × 100) was 67% and 61% in the right and left eye, respectively (normal <69%).[7]

Figure 1

Digital photographs showing megalocornea in Case 1 (a) and Case 2 (b)

Figure 2

Slit lamp photographs showing mosaic corneal dystrophy and cataract in the right (a) and left eye (b) in Case 1

Figure 3

Digital photographs showing hyperdeep anterior chambers in Case 1 (a) and Case 2 (b)

Figure 4

Ultrasound biomicroscopy showing enlarged iris–lens diaphragm in Case 1

Cataract extraction with scleral fixation of a polymethyl methacrylate IOL (Aurolab, Madurai, Tamil Nadu, India) was planned in the right eye. Two standard scleral incision pockets were made at 3 and 9 o'clock positions, 2 mm away from the limbus. After a large (7 mm) capsulorhexis, a 5.0 mm scleral tunnel incision was made superiorly and the AC was entered with 3.2 mm keratome. Phacoemulsification was performed after delivering the lens matter into AC. A 10-0 prolene needle was passed 1 mm away from the limbus and from the opposite end, a bent 26-gauge needle was passed, and the prolene needle was exteriorized. A similar procedure was repeated at another site close to the previous entry. Both sutures were exteriorized through the superior scleral tunnel and tightened to the eyes of scleral fixated IOL. Subsequently, IOL was inserted below the iris and after confirming the centration; both suture ends were pulled and tightened with multiple knots.

At 1 month after surgery, the vision was 6/6 in the right eye with a residual error of − 0.5 DCyl at 80° without pseudophacodonesis [Figure 5a].

Figure 5

Slit lamp photographs showing central and stable intraocular lens in Case 1 (a) and Case 2 (b)

Case 2

In contrast to the above case, this 43-year-old male had decentered IOL-bag complex, in the right eye and cataract [Figure 1b] in the left eye. The left eye vision was 2/60 whereas it was 20/30 in the right eye. He too had bilateral megalocornea [Figure 1b], hyperdeep AC [Figure 3b], and a normal axial length. He denied for any intervention in the right eye and consented for phacoemulsification in the left eye. After staining the anterior capsule with 0.1 ml of 0.06% trypan blue (Auroblue, Aurolab, Madurai, Tamil Nadu, India), 4 marks were made on either side of the center of cornea using a 5 mm caliper. A capsulorhexis was made within these marks. This was to ensure that a round capsulorhexis of a diameter of not more than 5 mm was obtained. A superior clear corneal tunnel was constructed and the rhexis margin was spread out on cornea to confirm the size of the rhexis. Phacoemulsification was completed and a standard 3-piece IOL (Acrysof MA60AC, Alcon Labs, Fort Worth, TX, USA) was injected under the iris such that both the haptics lay in the sulcus. The optic of IOL was tapped downward with sinskey hook such that it got captured under the anterior capsulorhexis margin. The same was confirmed on higher magnification.

At 1 month after surgery, the vision was 6/6 in the left eye with a residual error of − 0.25 DSph/−0.5 DCyl at 80° without pseudophacodonesis [Figure 5b].

Discussion

Cataract surgery in patients with anterior megalophthalmos is full of challenges. The challenge starts with the construction of incision. Leakage of the clear corneal wound has been reported due to thinness of cornea (in Case 1, the corneal pachymetry was <500 μ in both eyes).[4] Therefore, scleral tunnel incision was planned in our patients and subsequently sutured them. The second challenge is with visualization because of hyperdeep AC and mosaic corneal dystrophy. To overcome this, we stained anterior capsule similar to cases described by Lee et al.[1] and Vaz and Osher.[14] Moreover, we performed successful phacoemulsification after prolapsing the lens matter into deep AC. This avoided stress on the weak capsule-zonule complex and also helped in visualization of phaco maneuvers. The phaco machine parameters were kept at lower bottle height and lower vacuum settings.

The challenge continued with the selection of IOL. Before 1991, 32 cases of cataract extraction were reported without implantation of IOL.[89] IOL implantation in anterior megalophthalmos began in 1991; however, cases of malposition of standard size IOL were reported.[69] To overcome this, modification in size [46] and the techniques [125] of IOL implantation were subsequently introduced.[12456]

We adopted different techniques of PCIOL implantation in our cases. In Case 1, we achieved IOL stabilization by fixing it to sclera whereas in Case 2 by capturing the optic through an anterior capsule opening with haptics lying in sulcus. The second technique of IOL fixation was also described by Gimbel and DeBroff though their description was related to the patients with normal dimension anterior segment.[10] Jain et al.[11] have recently described the second technique with the insertion of IOL through the superior scleral tunnel in contrast to the superior clear corneal tunnel as described in our case.

Besides the above challenges, even the diagnosis of anterior megalophthalmos poses challenge due to its rarity. Although the condition is diagnosed clinically, clinicians often use UBM for confirmation especially to find out vitreous index as we have done in our cases. However, we have not used it postoperatively as described by Nawani et al.,[12] in which they have reported partial resolution of UBM findings after cataract surgery.

Conclusion

These cases highlight the spectrum of challenges and their successful management while performing phacoemulsification in patients with anterior megalophthalmos. Scleral fixation and optic capture within the anterior capsulorhexis, though technically challenging procedures, offer stable fixation of IOL postoperatively.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.