High-hyperopia database, part I: clinical characterisation including morphometric (biometric) differentiation of posterior microphthalmos from nanophthalmos

Abstract

Purpose To characterise and differentiate posterior microphthalmos (PM) and nanophthalmos (NO) using morphometric parameters. Patients and methods Consecutive case database of patients with hyperopia 4+7.00 D sphere was analysed retrospectively for clinical and biometric characterisation. Thirtyeight consecutive high-hyperopic subjects (75 eyes) with axial lengths o20.5 mm underwent uniform comprehensive ocular evaluation. Twenty-five subjects were diagnosed as PM and 13 as NO based on the horizontal corneal diameter. Parameters analysed included visual acuity, refraction, horizontal corneal diameter, anterior chamber depth, lens thickness, axial length, fundus changes, and associated ocular pathology. Primary outcome measures: ocular biometry difference between PM and NO. Secondary outcome measures: differences in associated ocular pathologies between PM and NO. Results Hyperopia ranged from +7 to +17 D and was similar in the two groups. Lens thickness was statistically more in NO than in PM group (4.53 ± 0.75 mm vs 3.82 ± 0.48 mm, P o0.001), whereas anterior chamber depth was more in the PM than in NO group (3.26 ± 0.36 mm, vs 2.59 ± 0.37 mm, Po0.001). NO had higher association with angle-closure glaucoma (66.7% vs 0%) and pigmentary retinopathy (38.5 vs 8.0%) but lesser association with macular folds (0% vs 24%) as compared with PM. NO was associated with poorer visual acuity.Conclusion PM and NO have significant differences in lens thickness, anterior chamber depth, prevalence of glaucoma, pigmentary retinopathy, macular pathology, and visual acuity while being similar in hyperopic refraction.

Nanophthalmos: A Review of the Clinical Spectrum and Genetics

“…It usually presents as a small hyperopic eye set into a deep orbit, with narrow palpebral fissures [ 15 , 16 ]. A high hypermetropic refractive error is an invariable feature, ranging from +8.00 D sphere to +25.00 or higher [ 2 , 17 ]. However, the diagnostic criteria vary widely across the literature and considering only one parameter is simplistic.…”

“…However, other groups point to the clinical and structural differences between these conditions, such as the cornea size and curvature, anterior chamber depth, lens thickness, angle characteristics, and propensity for complications [ 2 , 3 , 20 ]. Relhan et al [ 2 ] biometrically analyzed eyes of 38 patients with high hyperopia (defined in the study as greater than +7.00 D spherical equivalent on refraction), all of them with an axial length equal or less than 20.5 mm. In this study, they defined the patients with corneal diameters below 11.0 mm as nanophthalmic and those with corneal diameters greater than or equal to 11.0 mm as posterior microphthalmos.…”

“…In this study, they defined the patients with corneal diameters below 11.0 mm as nanophthalmic and those with corneal diameters greater than or equal to 11.0 mm as posterior microphthalmos. They found that nanophthalmic eyes have shallow anterior chamber depth, thicker lens, and steeper cornea, in comparison with posterior microphthalmic eyes [ 2 ]. They also reported different tendencies to complications: the incidence of angle-closure glaucoma was 69.23% in the nanophthalmos group versus 0% in the posterior microphthalmos group, while the incidence of macular folds was 0% versus 24%, respectively [ 2 ].…”

Tietz/Waardenburg type 2A syndrome associated with posterior microphthalmos in two unrelated patients with novel MITF gene mutations

“…In this clinical report, the patient's refraction showed a high hyperopic error, reduced anteroposterior axial length, normal‐sized corneas, and anterior segments indicating posterior microphthalmos [Relhan et al, ]. Only one patient (the isolated patient) had a reduced anterior chamber (OD = 1.88 mm, OS = 2.37; normal value = 3 mm), which has been described in patients with nanophthalmos but not those with posterior microphthalmos [Chalam et al, ].…”

“…Posterior microphthalmos is an uncommon developmental ocular disorder characterized by a small eye, defined as an eye with an axial length from 12.30 to 20.36 mm (average axial length in adults is 23.6 ± 0.7 mm) [Gordon and Donzis, ], high hyperopia, a normal‐sized cornea and normal anterior segment, retinal folds, and a propensity for uveal effusion [Khan, ; Relhan et al, ].…”