Data were collected from a total of 245 patients which satisfied criteria for sulcus implanted intraocular lens. For the patient characteristics (see Table 1), results showed a mean age of 61 years old with more males than females. Follow up period was 6 ± 2.42 months. For the surgical characteristics, majority of the sulcus implantation occurred during phacoemulsification primarily on the same sitting setup. Anterior vitrectomy was done in 97% of the total eyes and posterior vitrectomy was done in 21% of total eyes. 97% eyes had vitreous loss. There were 20% of which had dropped nuclear fragments.
For the IOL characteristics (see Table 1), majority of the sulcus implanted IOLs were single-piece; majority of which were foldable and 10% were rigid polymethymethacrylate intraocular lenses. Intraocular lens dimensions, namely the central thickness or the optic thickness, optic diameter and overall length, the single-piece IOLs were found to be relatively thicker in the central portion of the optic as compared with three-piece IOLs. Generally, single-piece IOLs were smaller as compared to three-piece IOLs.
In Figure 1, breaking down where the different IOLs were implanted, sulcus single-piece acrylic IOLs predominates during phacoemulsification. Single-piece rigid PMMA IOLs were implanted more in ECCEs. Majority of the etiologies of the complicated surgeries were brought about by dense cataracts, followed by myopia and small pupil (see Table 2).
Best corrected distance visual acuity (BCDVA) was represented in the graph as logarithm of the minimal angle of resolution or logMAR units. Generally, the preoperative BCVA was 0.75 logMAR units or 20/100 or worse. Postoperatively, there was an improving trend of visual outcomes for both three-piece and single-piece acrylic IOLs as time passed (see Figure 2). Table 3 shows comparison between the preoperative and postoperative BCVA. There was a significant difference across all points (P = 0.04). However, comparing the outcomes of a single-piece vs three-piece IOL per period in time, single-piece and three-piece IOLs demonstrate no superiority over the other.
Correlation between the general presence of preoperative risk factors to the presence of complications showed no sufficient evidence to conclude that the presence of preoperative risk factors was associated with occurrence of postoperative complications (see Table 4).
Moving to the complications, there were more complications in single-piece acrylic IOL group (65%) versus three-piece IOL group (40%). The following complications were elevated intraocular pressure that may or may not progress to glaucoma, corneal edema, loss of centration, pigment dispersion and retinal detachments.
Although anterior chamber inflammation is expected after a surgery, we identified the presence of inflammation postoperative and which of these inflammations were only transient (occurring less than 2 weeks), or persistent (more than 2 weeks). Majority of the inflammation developing postoperatively were noted to be transient at around 92% in both groups. Around 5-7% or 16 eyes had persistent inflammation. From these 16 eyes, 13 eyes from single-piece and three-piece groups resolved after 4 weeks of topical steroids managed by the surgeon however, 3 eyes from single-piece group warranted uveitis specialist co-management. The cumulative incidences of postoperative inflammation between single-piece and three-piece IOLs showed no sufficient evidence to conclude that there is a significant difference (see Table 5).
For the elevated intraocular pressures, we noted more elevated intraocular pressure in three-piece IOLs as compared to single-piece. Of these 56 eyes which had elevated IOP, 19 eyes spontaneously resolved without treatment, and a total of 41 eyes in both groups were managed with topical medications. Twenty-eight eyes were from single-piece group; 8 eyes from three-piece group. Most common medications given to address the elevated IOP were timolol (63%), acetazolamide (21%) and brimonidine (19%). Approximately half (n=20) of the eyes were controlled with only 1 topical medication, 12 eyes required 2 medications, 2 eyes required 3 medications, and 1 eye for 4 medications. Mean IOP elevations of 23 mmHg and 21 mmHg for single-piece and three-piece, respectively. Twelve (12) eyes warranted a glaucoma specialist co-management. Ten (10) from them were from the single-piece group, 2 eyes from the three-piece group. Three (3) eyes progressed to glaucoma and all of these were from the single-piece group. Of these 3 glaucomas identified, two were open angle glaucomas, and one was a secondary angle closure glaucoma. One eye from these required trabeculectomy. Elevated IOP had a mean 30 days of duration. We categorized an elevated IOP into the following: early or defined as onset of elevated IOP within 2 weeks, late – onset is beyond 2 weeks; transient or within 4 weeks regardless of management, or chronic or more than 4 weeks. We have found that there was a significantly higher proportion of early onset increase in IOP in single-piece group than in three-piece group, and that there was higher incidence of late onset increase in IOP in three-piece group than in single-piece group (p-value = 0.02). With regards to chronicity, there were more chronically increased IOP in three-piece group than in single-piece group, but this was not significant. Among those eyes needing glaucoma co-management, we have found that the IOLs implanted have a significantly lower median optic diameter than those without need for glaucoma co-management. Central thickness and overall diameters were found to not correlate with need for glaucoma co-management.
A total of 89 eyes had corneal edema postoperatively. Fifty (57) from which were observed, and no medications were given. Thirty-two (32) eyes received sodium chloride and no patients were deteriorated to corneal decompensation. Most corneal edemas occurred transiently, operationally defined as within 2 weeks, with spontaneous resolution, mostly not needing sodium chloride treatment. Around 45% of patients from single-piece foldable group extended to persistent corneal edema, or more than 2 weeks of edema, because of either a peripheral DM detachment, or scarring progression. Some of these patients with persistent corneal edema were only focal not affecting the visual axis. There was no sufficient evidence to conclude that there is a significant difference in the cumulative incidence of postoperative corneal edema between single-piece and three-piece IOL.
There were more losses of intraocular lens centration with single-piece acrylic IOLs than three-piece IOLs. For loss of IOL centrations, we operationally classified loss of centration as decentration, subluxation and dislocation. IOL decentration is loss of centration where IOL is retained in the ciliary sulcus, but the geometric center is not in the visual axis. Subluxation is partial displacement out of the ciliary sulcus (i.e., haptic may be incarcerated in anterior chamber or iris), but is confined within the anterior segment (i.e., anterior chamber, incarcerated in the iris). Dislocation is complete displacement out of the ciliary sulcus (i.e., entire IOL in the anterior chamber, IOL dropped in the posterior segment)8,9,10. Majority of loss of IOL centration occurred in eyes implanted with single-piece acrylic IOLs. Two eyes had decentrations, 4 subluxations and 9 dislocations all of which dropped into the retina. There were 2 decentrations and 1 subluxation in three-piece group. 8.42% developed loss of IOL centration in a shorter onset of time of 7 days in single-piece group. Despite the high number of decentrations in the single-piece group, there was no sufficient evidence to conclude that this was significant. Those with loss of centration have significantly lower median overall and optic diameters than those without loss of centration (see Table 6).
A total of 15 patients had pigment dispersion: 13 from single-piece group and 2 from three-piece group. No patients were diagnosed with pigment dispersion glaucoma. Three (3) eyes noted with retinal detachment at a mean onset of 5 days in single-piece IOL group. All eyes with retinal detachment were predisposed to IOL explant prior to the retinal detachment.