|Year : 2021 | Volume
| Issue : 1 | Page : 41
Nanophthalmos refractory to medical treatment: What to do?
Carolina Saldarriaga-Santos1, Hector Fernando Gómez Goyeneche2
1 Department of Ophthalmology, Doctor in Medicine, Diagnóstico Ocular del Country, Bogotá, Colombia
2 Department of Ophthalmology, Ophthalmologist, Glaucoma Specialist, Diagnóstico Ocular del Country, Colombia
|Date of Submission||24-Nov-2020|
|Date of Acceptance||10-Nov-2021|
|Date of Web Publication||23-Dec-2021|
Hector Fernando Gómez Goyeneche
Diagnóstico Ocular del Country, Carrera 16#82-95 Cons. 702, Bogotá
Source of Support: None, Conflict of Interest: None
Nanophthalmos, a congenital rare condition, is defined as a small eye characterized by hypermetropia, narrow anterior chamber, and thickened choroid and sclera. These features create an environment with high risk of developing angle-closure glaucoma (AGC) and higher risk of intraoperative and postoperative complications. This is a case of young female patient with nanophthalmos, chronic angle closure, elevated intraocular pressure (IOP) refractory to medical therapy, iridotomy, and iridoplasty, yet without glaucomatous changes. In a case of nanophthalmos refractive to medical treatment, it is challenging to decide whether lowering IOP and preventing ACG are worth the risk of vision reduction by intraocular lens miscalculation or surgical complications.
Keywords: Angle-closure glaucoma, case report, intraocular lens calculation, microphthalmos, nanophthalmos
|How to cite this article:|
Saldarriaga-Santos C, Gómez Goyeneche HF. Nanophthalmos refractory to medical treatment: What to do?. Pan Am J Ophthalmol 2021;3:41
|How to cite this URL:|
Saldarriaga-Santos C, Gómez Goyeneche HF. Nanophthalmos refractory to medical treatment: What to do?. Pan Am J Ophthalmol [serial online] 2021 [cited 2022 Jan 29];3:41. Available from: https://www.thepajo.org/text.asp?2021/3/1/41/333542
| Introduction|| |
Nanophthalmos is a congenital condition, considered part of the clinical spectrum of microphthalmos or small eye phenotype. However, its diagnostic criteria vary among the ophthalmic literature. Lappas et al. define nanophthalmos as eyes with an axis length of <21 mm and narrow anterior and posterior segments, without embryonic malformations. Yalvac et al. stablish diagnosis with an axis of <20.5 mm instead, and include moderate to severe hypermetropia, thickened choroid and sclera, and high lens-to-eye-volume ratio to the diagnosis criteria. Despite the exact diagnostic criteria, the typical nonophthalmic eye involves complex features such as moderate to high hypermetropia, small cornea diameter, shallow anterior chamber, marked iris convexity, narrow angles, and thickened choroid and sclera.,,,
Accurate prevalence of nanophthalmos is unclear, however, Stallings et al. found that the prevalence of the complete spectrum of microphthalmos in the USA was around 1.5/10,000 newborns. It is thought that nanophthalmos has strong genetic bases, considering it occurs as a consequence of arrest in development of the eye in early ocular embryogenesis.
It is well known that nanophthalmos has a high propensity for angle-closure glaucoma (ACG), which usually occurs between the fourth and the sixth decade of life., Due to the complex anatomy of these eyes and its significant risk and complications, the management of ACG in nanophthalmos can be challenging.
We present the case of a young female patient with nanophthalmos, chronic angle closure, elevated intraocular pressure (IOP) refractory to medical therapy, iridotomy, and iridoplasty, yet without glaucomatous changes.
| Case Report|| |
We present the case of a 32-year-old Colombian female with nanophthalmos in both eyes, who presented with a 1-year history of occasional ocular pain in the right eye. She had a recent ocular hypertension diagnosis in both eyes, for which she was medicated with dorzolamide 2%, timolol 0.5%, brimonidine 0.2%, and latanoprost 0.005%. She had been treated with iridotomy and iridoplasty 2 years before. Other than her diagnosis of nanophthalmos, she did not have any other important personal or family history.
At ocular examination, corrected visual acuities OD +13.25 −0.75 × 010 (20/40) and OS +13.00 −1.25 ×170 (20/30). Biomicroscopy showed clear corneas and shallow anterior chambers with severe iris convexity. Goldmann applanation tonometry was 30/32 mmHg. Gonioscopy revealed bilateral appositionally closed angles, which opened with indentation, and with peripheral anterior synechiae in superior quadrant OD [Figure 1]. Fundoscopy showed small optic nerve heads with an optic nerve cup-to-disk ratio of 0.1 in both eyes, without glaucomatous changes [Figure 2]. The rest of the ocular examination was normal.
|Figure 1: Gonioscopy by NGS-1 (NIDEK Co, Gamagori, Japan) device. A and B The circular display of right eye and left eye respectively. C. Section displayed of superior quadrant right eye which shows a peripheral anterior synechiae. I = inferior; N = nasal; S = superior; T = temporal.|
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|Figure 2: Color Fundus Photograph shows optic discs with sharp margins with cup-to-disc ratio of 0.1. The vasculature is normal in course and caliber. There are no lesions, scars of pigmentary changes|
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Biometry confirmed nanoftalmos with an axial length of 16.60/16.63 mm with anterior chamber depth of 1.72/1.61mm and phacometry of 556/555 μm. In addition, traditional formulas to calculate intraocular lens (IOL) power throw different values, which would make it difficult to choose one if cataract surgery is required [Figure 3]. Ophthalmic ultrasound biomicroscope showed narrow angles between 0.07° and 12.49°, with marked iris convexity [Figure 4]. Nonetheless, visual fields (Humprhey 24-2 VF), optical coherence tomography (SD-SLO Nidek RS-3000 Advance II OCT), and Heidelberg retinal tomography-3 within normal limits, without any glaucomatous changes [Figure 5], [Figure 6], [Figure 7], respectively).
|Figure 3: Ophthalmic Ultrasound Biomicroscope (UBM) shows narrow angles (12.49º and 6.32º) in the left eye with an anterior chamber depth of 1.53 mm.|
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|Figure 4: Visual fields: Humphrey 3 (HFA3) 24-2 SITA Standard report, are reliable for both eyes. Glaucoma hemifield test (GHT), Visual Field Index (VFI) Mean deviation (MD) are Within normal limits, and the Pattern deviation map without detectable defects for both eyes|
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|Figure 5: Optical coherence tomography (Nidek, RS-3000 Advance II) Disc Circle (A) and Disk Map (B) graphs shows retinal nerve fiber layer (RNFL) outside normal limits for both eyes. Macula Map (C) shows ganglion cell complex within normal limits in both eyes|
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|Figure 6: Heidelberg retinal tomography shows small–size optic disc, for rim area and rim volume within normal limits; with shallow excavation; the optic disc contour is difficult to define; without asymmetry|
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|Figure 7: Intraocular lens power calculation with A. Haigis and B. Hoffer Q. The difference in the calculation is from 1 to 9 Diopters.|
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| Discussion|| |
This female patient meets the clinical features and all the diagnostic criteria declared by Yalvac et al. These classic characteristics of nanophthalmos constitute a multifactorial mechanism for ACG. First, hypermetropia, a main characteristic of this condition, is a risk factor of ACG. Second, the high lens-to-eye-volume ratio leads to a crowded anterior segment in a chamber that is already small. This leads to narrow angles, formation of peripheral anterior synechiae, relative pupillary block, and elevated IOP. Third, the thickened choroid and sclera reduce venous drainage, causing uveal effusion and leading to zonular weakening. Consequently, displacement of the iris occurs by anteriorly rotated ciliary processes, allowing a ciliolenticular block., Evidently, this patient's clinical features can explain her constant elevated IOP. In a young patient without signs of glaucoma, it is crucial to low IOP to prevent the disease from developing.
In addition to the challenging management of nanophthamos, most recommendations are usually based on personal experiences. Several authors state that there is a poor respond to medical treatment, so the first line of management should be iridotomy to eliminate pupillary block, followed by argon-laser peripheral iridoplasty if the angle remains appositionally closed.,, Considering nanophthalmos has a higher intraoperative and postoperative complications rate, including choroidal detachment, nonrhegmatogenous retinal detachment, malignant glaucoma and expulsive bleeding, surgical management is recommended to be the last resource., Nonetheless, other authors consider that since the high lens-to-eye-volume ratio is the main anatomical factor that causes crowding anterior chamber and elevated IOP, cataract surgery should be performed., Lappas et al. state that filtering glaucoma surgery and cyclo-destructive interventions are considered as the last option in progressive glaucoma refractory to therapy. Yalvac et al. did a retrospective study of patients with nanophthalmos who underwent trabeculectomy + Mitomycin-C + inferior sclerotomy surgery and found that IOP control was accomplished, but uveal effusion and the need for subsequent cataract surgery were the major complications.
In this case, the patient's angles remain appositionally closed despite the iridotomy, iridoplasty, and full medical management. IOP was not within normal limits, although neither was at critical values that would indicate an urgent intervention. What makes this case stand out is the difficulty to decide whether lowering IOP and preventing ACG are worth the risk of a surgical management. Even though the OCT looks normal, we know that retinal nerve fiber layer thickness is thicker considering the size of the eye. Moreover, if phacoemulsification is chosen with her current corrected vision, it is crucial to analyze which formula to use for IOL power selection since the IOL power goes from 48 to 54 D.
| Conclusion|| |
More investigation in nanophthalmos, diagnostic methods, IOL calculation, and ACG are needed to better approach these cases. Risk/benefit ratio and potential surgical complications must be considered and clearly explained to patients.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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