This article is more than 5 years old. Information may no longer be current.
Ultrasound biomicroscopy used to report characteristics of transscleral-fixated glued IOLs
A study found a 17.4% incidence of microscopic optic tilt with this technique.
Click Here to Manage Email Alerts
Glued transscleral IOL fixation is a type of scleral fixation of a posterior chamber IOL without sutures in eyes with inadequate capsules. With the introduction of glued foldable or injectable IOLs through small incisions, this technique has been of recent interest. Sutured scleral-fixated posterior chamber IOLs in eyes with inadequate capsular support have been studied postoperatively regarding tilt and haptic location. To our knowledge, sutureless transscleral-fixated IOL position in a living eye has not been reported. In the study presented here, we reported the characteristics of transscleral-fixated glued IOLs using ultrasound biomicroscopy and its relation to clinical outcomes.
Study
A prospective ultrasound biomicroscopy (UBM) evaluation of 46 eyes with glued transscleral-fixated IOLs was performed. Exclusion criteria were a postoperative period of less than 6 months, uncooperative patients and aniridia. The surgery was performed with the known technique of glued transscleral fixation of a posterior chamber IOL. UBM scan with the Marvel (Appasamy Associates) was performed.
Optic tilt was measured by drawing a line along the hyperreflective iris pigment epithelium layer, marking the iris as the plane of reference for the optic position (Figure 1). The optic was considered not tilted when the reference lines along the iris and the optic were parallel. The distance between the iris pigment epithelium and the optic was measured in four positions: superior (12 o’clock), inferior (6 o’clock), nasal (3 o’clock in the right eye and 9 o’clock in the left eye) and temporal (9 o’clock in the right eye and 3 o’clock in the left eye) in relation to the iris (Figure 1). IOL optic tilt was measured in microns. The difference between superior and inferior distance was noted as vertical tilt. The difference between nasal and temporal distance was noted as horizontal tilt. A difference of more than 100 µm between two positions was considered as optic tilt. The haptic locations were determined by tracing the high reflection obtained from the haptic to a position closest to the eye wall. Haptic position was designated in the ciliary sulcus and ciliary process (pars plicata). The mean follow-up was 24.6 ± 14.3 months (range: 6 to 56 months).
Figure 1. Ultrasound optic tilt measurement. The optic tilt was measured by drawing a line along the hyperreflective iris pigment epithelium layer, marking the iris as the plane of reference for the optic position. The distance was measured in both vertical and horizontal axes.
Images: Agarwal A
Figure 2. UBM image showing the haptic above the ciliary process in the ciliary sulcus.
Figure 3. Clinical photograph (left) and UBM image (right) showing the optic tilt in an eye with one haptic in the sulcus and the other haptic in the pars plicata.
Figure 4. Top. Clinical photograph (left) and UBM image (right) of glued IOL in which both haptics were in the pars plicata. Bottom. Clinical photograph (left) and UBM image (right) showing iris-IOL contact (arrow) at the haptics. Note: No pigment dispersion on IOL seen.
Eight eyes (17.4%) showed optic tilt, and 38 eyes (82.6%) showed no optic tilt.
Discussion
IOL position is vital, not only for attaining potential vision but also to prevent complications. Maggie initiated the sutureless transscleral fixation of posterior chamber IOLs in eyes with inadequate capsules. Later, Gabor introduced the intrascleral haptic fixation of a standard three-piece posterior chamber IOL without sutures and showed good results. The tilt in 17.4% eyes did not show significant correlation with corrected distant vision. We also noted that the microscopic tilt was not significant enough to affect the postoperative refraction. Moreover, the ocular residual astigmatism did not differ between the eyes with and without optic tilt. Out of 92 haptics examined, 85 (92.4%) were in the sulcus (Figure 2) and seven (7.6%) were in the ciliary process of the pars plicata. Three of the seven haptics in the ciliary process had the other haptic in the sulcus and measured a UBM optic tilt of more than 100 µm (Figure 3).
In the glued IOL method, the intended position was achieved in 92.4% of the haptics. This shows that the reliability is good with the glued IOL technique as compared with sutured scleral fixation of posterior chamber IOLs. In the suture-fixated posterior chamber IOL technique, the suture needle is blindly passed through the ab externo method. However, in the glued IOL method, the haptics directly come through the sclerotomies made in the measured position on direct visualization. The exact anatomical positioning of the sclerotomy is an important step in the glued IOL method. Any difference in the two sclerotomy wounds can affect the final position of the haptic and can induce optic tilt. This has been shown in our results, in which three of seven eyes with one haptic in the ciliary sulcus and the other in the pars plicata had tilt of more than 100 µm. There were two eyes with both haptics in the pars plicata but without optic tilt (Figure 4, top). Because the position of externalization was equal on both sides, there was no significant tilt observed in UBM. Incarcerating a longer part of the haptic stabilizes the axial position of the posterior chamber IOL, leading to a decrease in the incidence of IOL tilt. However, in our series, there was no association between the optic tilt and haptic location. Out of three eyes with iris-IOL contact, one eye had iris-optic contact in the mid-periphery of the IOL, and two eyes had iris-haptic contact (Figure 4, bottom).
To summarize, from this UBM study, we were able to know that there was microscopic IOL tilt in glued transscleral-fixated IOLs. However, the incidence was less than the microscopic optic tilt as reported in sutured scleral-fixated posterior chamber IOLs.