Dr. Jitendra Nenumal Jethani, J09433, Dr. Monika Jethani
Authors
Dr. Jitendra Jethani
Dr. Monika Jethani
Abstract
Patients with microcornea are usually left aphakic as the routine IOLs with their large size would end up with disastrous complications such as angle closure and glaucoma. The routine size IOLs are therefore not suitable. We planned to use custom made optic and total size small IOLs for these eyes with corneas smaller than 9.0 mm diameter.
All the patients had cornea smaller than 9.0 mm as their largest diameter. All IOLs were single piece PMMA IOL with variable optic size (4 to 5 mm) and variable total size (10 to 10.5mm) depending upon the size of the cornea.
A total of 12 eyes (n=10) were implanted the small sized custom made IOL. The mean age was 11.7 +/- 12 years. The visual acuity was 20/80 or better in 10 eyes and 20/200 or better in rest of the five eyes. The mean horizontal corneal diameter was 8.83 +/- 0.3 mm and the vertical diameter was 8.54 +/- 0.4 mm.
The small sized IOLs are safe in both children and adult and are feasible option to treat aphakia with microcornea.
Cataract management in patients with small corneas is always a challenge.1-3Posterior chamber intraocular lens (PC IOL) is a well accepted procedure for children as well as adults. Yu et al and Sinskey et al have mentioned the problems with PCIOL implantation in children with microcornea. The common problems are corneal opacity, membrane formation and glaucoma. Apart from the small size of cornea the shallow anterior chamber may also contribute to the complications like Glaucoma when a normal sized IOL is implanted. Glued IOLs have also been tried successfully in patients with microcornea with or without haptic trimming.4We did a study to implant reduced size IOLs for patients with microcornea.
Materials and Methods
Preoperative examinations were conducted for bilaterality,corneal diameters, axial lengths, eye abnormalities andsystemic abnormalities.Corneal diameters of each eye were measured by using acaliper from white to white horizontally during lens surgery.
All the surgeries performed were secondary IOL implantations. All the patients had cornea smaller than 9.0 mm as their largest diameter. All IOLs were single piece PMMA IOL with variable optic size (4 to 5 mm) and variable total size (10 to 10.5mm) depending upon the size of the cornea.
Secondary PC-IOL implantations were conducted usingscleral tunnel incision superiorly. Posterior synechia of theiris were carefully separated and proliferated lens materialswere completely removed. PC-IOLs were implanted into thesulcus and the scleral wound was closed with interrupt 10-0Vicryl sutures. Polymethylmethacrylate (PMMA) one piecePC-IOLs were implanted in all eyes. Most patients received 5 mm optic with 10.5 mm haptic IOL (Aurolab, India), 3 patients received 4 mm optic and 10 mm haptic (IO care, India) and 4 patients received 4.5 mm optic and 10.5 mm haptic size. None of the IOLs was square edge.
All patients were followed up for at least 18 months aftersecondary PC-IOL implantation surgery. Postoperative resultsand complications were determined by measuring refraction,axial length, intraocular pressure with a noncontact tonometerand by using a handheld slit lamp and by indirectophthalmoscopic examinations. Vision assessment was madeusing a fixation pattern in nonverbal children and a Snellenacuity chart in the verbal group.
Results
A total of 12 eyes (n=10) were implanted the small sized custom made IOL. The mean age was 11.7 +/- 12 years. The visual acuity was 20/80 or better in 10 eyes and 20/200 or better in rest of the five eyes. The mean horizontal corneal diameter was 8.83 +/- 0.3 mm and the vertical diameter was 8.54 +/- 0.4 mm. The mean axial length was 19.5 +/- 1.2 mm. The mean IOL power was 31.92 +/- 4.1 diopters. The meanfollowup was 20 +/- 2.3 months.
None of the patients developed glaucoma although 3 patients developed optic capture. All the IOLs were placed in the sulcus on the posterior capsular support. The vertical diameter of cornea all the eyes was smaller or equal to the horizontal diameter of the cornea. All the IOLs were therefore placed horizontally.
Discussion
Small corneas present a unique challenge for implantation of IOLs of normal size especially if the corneal size is smaller than 9.0 mm. Yu et al have described complications including corneal opacity, glaucoma and membrane formation. 2, 5 A normal sized IOL may cause crowding in the angle and the resulting angle closure glaucoma when the IOL is implanted in the sulcus as secondary IOL. Agarwal et al 4 have described implanting a glued IOL where haptic externalisation may circumvent this problem. Apart from the IOL sizing another issue is the IOL power which was more than 34 in 6 eyes in our series of 12 eyes. The IOL power was calculated with SRK-T formula.
Both the sizing and the power of IOL can be managed with custom made IOLs of small size. In our case, we used both the ready made IOLs from aurolab, India and custom made IOLs from IO care, India.
The sizing is an important issue. We measured all the corneas and added 1.5 mm to the total size of IOL on the horizontal diameter considering this as the size of the sulcus. None of our patients had decentered IOLs post surgery. The Optic size was selected on the basis of the vertical diameter or the minimum diameter of the cornea. For corneas between 7.5-8.5 mm we selected 4.0 mm optic size, for cornea diameter between 8.5-8.75 mm we selected 4.5 mm optic diameter and for 9.00 mm corneal size we selected optic diameter as 5.0 mm.
Conclusion
We believe that customising the IOL size is important to prevent complications in patients undergoing secondary IOL implantation in microcornea. The reduced size IOLs are safe in microcorneas.
References
- Yu YS, Kim S, Choung H. Posterior Chamber Intraocular Lens Implantation in PediatricCataract with Microcornea and/or Microphthalmos. Korean Journal of Ophthalmology. 2006; 20: 151- 155
- Yu YS, Lee JH, Chang BL. Surgical management ofcongenital cataract associated with severe microphthalmos. J Cataract Refract Surg2000;26:1219-24.
- Sinskey RM, Amin P, Stoppel J. Intraocualr lens implantationin microphthalmic patients. J Cataract Refract Surg1992;18:480-4.
- Ashok Kumar D, Agarwal A, Sivangnanam S, Chandrasekar R, Agarwal A.Implantation of glued intraocular lenses in eyes with microcornea.J Cataract Refract Surg.2015;41:327-33.
- de Sa LCF. Lens implantation in microphthalmic eyes. JCataract Refract Surg1993;19:323.