PubMed · 15411303
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A COWAN. 1950. Aphakia.. https://pubmed.ncbi.nlm.nih.gov/15411303/
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AIM: To compare the following two methods of paediatric secondary posterior chamber intraocular lens (PCIOL) determination with the Holladay formula: (1) estimation from the aphakic refraction alone (using assumed keratometry (K) of 44 diopters); and (2) calculation based on preoperative measured biometry. METHODS: (1) Retrospective medical record review in a referral eye hospital of children with aphakia aged < or =12 years who underwent secondary PCIOL implantation with an Alcon MA60BM lens; (2) PCIOL determination for a plano refraction by the above two methods (estimation and calculation); and (3) prediction of pseudophakic refraction for the PCIOL actually implanted by the above two methods compared with the actual pseudophakic refraction. RESULTS: 50 eyes of 30 children with aphakia were studied. The estimated (mean, 95% confidence interval (CI)) secondary PCIOL values (25.81, +/-1.65 D) and the calculated secondary PCIOL values (26.35, +/-1.50 D) were not significantly different (mean absolute value of the difference 1.86 D, 95% CI +/-0.41 D) by the two-tailed paired t test at alpha = 0.05 (p = 0.11). For each eye, the pseudophakic refractions predicted by the two methods for the PCIOL that was actually implanted differed, both from each other and from the actual pseudophakic refraction (repeated-measures analysis of variance, p<0.001; Tukey test, p<0.01). CONCLUSIONS: The method of PCIOL estimation from the aphakic refraction alone provides values similar to those obtained by a standard technique and can be useful if biometry is unavailable. Targeting a pseudophakic refraction in paediatric aphakia is prone to error.
CASE REPORT: Shortly after birth, a massive enlargement of the right eye was observed in an otherwise healthy male child. The cornea of the affected eye was vascularized and completely cloudy without a sharp border between cornea and sclera. The diagnosis of a congenital glaucoma was made but an operation was not undertaken because of the difficult anatomical situation and the lost function. When the child was almost 3 years old enucleation was performed to prevent complications due to corneal exposure, and to improve the cosmetic aspect. RESULTS: The morphological investigations of the enucleated eye disclosed findings typical of what is called in the literature "congenital anterior staphyloma" or "congenital corneal staphyloma", namely a massively staphylomatous cornea with superficial neovascularization, destruction of Bowman's layer, and absence of Descemet's layer as well as corneal endothelium. Angle structures were completely absent, and the corneal back-side was lined by a pigment epithelial layer and focally by an additional inner layer of non-pigmented epithelium. There was no anterior chamber. The lens was markedly diminished in size (microphakia) and partly embedded in the corneal stroma. Pars muscularis and pars ciliaris of the ciliary body were separated. Elongated, thin ciliary processes were extended towards the small lens while the pars muscularis was fully covered by the retina. CONCLUSIONS: This rare, complex malformation syndrome which can be easily distinguished from primary congenital glaucoma should not be reduced conceptually to the corneal staphyloma because this staphyloma constitutes only a part of the whole. Taking the leading morphological aberrations into consideration we would rather propose the new term " corneal staphyloma- anterior chamber agenesia- microphakia syndrome (CSAMS). We hypothesize that CSAMS may be due to a pathological fusion of the early anterior optic cup. As the posterior eye segment is often normal in CSAMS, a staphyloma excision along with a sclero-keratoplasty might be an alternative therapeutic option to avoid enucleation and restore ambulatory vision.
BACKGROUND: The risk of glaucoma among aphakic children is as high as 32%, based primarily on intraocular pressure (IOP) measurements. Although IOP may be falsely elevated by increased central corneal thickness, central corneal thickness (CCT) values have not been reported in this population. METHODS: Patients from the practices of 2 pediatric ophthalmologists and 2 glaucoma specialists had measurements of CCT, IOP, and optic nerve cupping, with visual field analysis when possible. Normal fellow eyes of unilateral aphakes and pseudophakes were included as controls. RESULTS: In 36 aphakic and 6 pseudophakic eyes CCT averaged 660 microns compared with 576 microns for phakic fellow eyes (P < 0.0001). Glaucoma, defined by IOP at least 35 mm Hg or by IOP at least 22 mm Hg associated with optic nerve changes, occurred in 21% of 28 aphakic patients but in no pseudophakic patient. CONCLUSIONS: CCT in aphakic/pseudophakic children is substantially increased compared with control patients. These values may be important in interpreting IOP measurements in these children.