Anterior megalophthalmos in a family with 3 female siblings

Calculating intraocular lens power in anterior megalophthalmos: A case report

Introduction

We report a case of a man with cataract and anterior megalophthalmos (AM), in which some myopia was retained when calculating intraocular lens (IOL) power using the Haigis formula to avoid postoperative farsightedness.

Case description

A 59-year-old Chinese man was referred to our clinic for cataract surgery in his right eye. He had strong bilateral megalocornea, and his left eye had undergone surgery four times. After complete preoperative examinations and repeated biometry, the Haigis formula was used, and a 3-piece IOL was implanted with a target power of −1.97 D. At 1-year follow-up, the patient showed the best-corrected distance vision of 20/20 with the refraction of −1.50 DC × 160°, and the IOL was stable.

Conclusion

Our patient with anterior megalophthalmos showed postoperative hyperopia drift even though the Haigis formula was used as suggested in previous studies. To prevent farsightedness after surgery, some myopia should be retained when calculating IOL power. The Kane, Holladay II with AL adjustment, and Barrett Universal II formulas may be more accurate for calculating IOL power in such patients.

Biometric and Structural Ocular Manifestations of Anterior Megalophthalmos

Objective

The aim of this study was to examine the biometric ocular manifestations and structural ocular features of anterior megalophthalmos (AM).

Methods

Fifteen patients with AM (30 eyes) from the Eye & ENT Hospital of Fudan University were included. The age-matched control group consisted of 30 participants (30 eyes) who underwent Pentacam HR and IOLMaster 700 measurements for one normal eye. Data on demographics, biometric manifestations, and genotypes were carefully compared.

Results

A total of 15 patients with AM and 30 control patients were enrolled. There were no differences in age (37.27 ± 19.1 vs. 31.43 ± 19.69 years, P = 0.249) between these two groups. AM eyes were characterized by premature cataracts (11/30, 36.67%) and zonular weakness with lens subluxation (22/30, 73.33%) compared with the control group. Notably, 20 of the 30 AM eyes (66.67%) had significant posterior iris bowing, and 16 of the 30 AM eyes (53.33%) showed an enlarged ciliary ring on ultrasound biomicroscopy (UBM). Mean corneal curvature was lower in the AM eyes (42.01 ± 2.06 D vs. 43.14 ± 1.38 D, P = 0.023). There was no significant difference in corneal pachymetry and central endothelial cell count between the AM and control groups. Significant differences were found in terms of the anterior chamber and white-to-white (WTW) among the Pentacam HR and IOLMaster 700 in patients with AM (P < 0.05). The difference was 0.53 ± 0.48 mm and 0.36 ± 0.14 mm, respectively (P < 0.001).

Conclusion

The results of this cohort study conclude the biometric and structural ocular manifestations in Chinese cohorts. Posterior iris bowing (66.67%) and lens subluxation (73.33%) are the most characteristic findings in patients with AM with anatomical abnormalities of megalocornea and a deep anterior chamber, although corneal biometric manifestations of AM included flatter cornea and lower total corneal astigmatism. The knowledge of ocular manifestations of AM is important for diagnosis and preparation for the operation in advance to avoid intraoperative and postoperative complications. Significant differences were found in the anterior chamber and WTW values between the Pentacam HR and IOLMaster 700. Thus, we suggest that various examinations should be carefully considered before determining an AM diagnosis.

Megalocornea, anterior megalophthalmos, keratoglobus and associated anterior segment disorders: A review

Megalocornea and anterior megalophthalmos (megalocornea spectrum) disorders are typically defined by corneal diameter > 12.5 mm in the absence of elevated intraocular pressure. Clinical features overlap with keratoglobus but are distinct from buphthalmos and severe (globus) keratoconus. Megalocornea spectrum disorders and keratoglobus are primarily congenital disorders, often with syndromic associations; both can present with large and thin corneas, creating difficulty in diagnosis, however, only keratoglobus is typically progressive. Molecular genetics provide significant insight into underlying aetiologies. Nonetheless, careful clinical assessment remains intrinsic to diagnosis. Surgical management can be challenging due to the enlarged ciliary ring and weakened zonules in megalocornea spectrum disorders and the extreme corneal thinning of keratoglobus. In this review, the established literature on measurement of corneal diameter, diagnosis of megalocornea, anterior megalophthalmos and keratoglobus, differentiation from severe keratoconus, recent molecular genetics research and key surgical modalities in the management of these rare disorders are outlined and discussed.

Anterior megalophthalmos: Is visual restoration possible?

We report two cases of anterior megalophthalmos with cataract. Both cases have megalocornea, cavernous anterior chamber, enlarged iris–lens diaphragm, and normal axial length. The vision was less due to cataract. To restore vision, phacoemulsification was performed in each eye in both cases. Intraoperatively, to overcome anatomical challenges, we made scleral tunnel incision, stained anterior capsule, and fixated intraocular lens (IOL) by different techniques. In thefirst case, IOL was fixated through the sclera, whereas in the second case, IOL stabilization was achieved by capturing the optic in anterior capsulorhexis margin and placing the haptics in sulcus. Successful vision was restored in both cases without pseudophacodonesis.

Small lens for a big eye: Successful management of anterior megalophthalmos

We report a case of anterior megalophthalmos and complicated cataract, with apparently smaller lens in both eyes. The right eye had spontaneous retinal detachment. The child underwent cataract surgery in both the eyes with retinal detachment surgery in the right eye. Due to small size of the lenticular bag, a downsized customized intraocular lens (IOL) was implanted. Postoperatively, the IOL was well centered with ambulatory vision till 3 years of follow-up. This case describes this rare disorder and its association with apparently small-sized lens and discusses the course of its management, highlighting the visual rehabilitation with customization of IOLs.

Surgical Management of a Patient with Anterior Megalophthalmos, Lens Subluxation, and a High Risk of Retinal Detachment

The early development of lens opacities and lens subluxation are the most common causes of vision loss in patients with anterior megalophthalmos (AM). Cataract surgery in such patients is challenging, however, because of anatomical abnormalities. Intraocular lens dislocation is the most common postoperative complication. Patients with AM also seem to be affected by a type of vitreoretinopathy that predisposes them to retinal detachment. We here present the case of a 36-year-old man with bilateral AM misdiagnosed as simple megalocornea. He had a history of amaurosis in the right eye due to retinal detachment. He presented with vision loss in the left eye due to lens subluxation. Following the removal of the subluxated lens, it was deemed necessary to perform a vitrectomy in order to prevent retinal detachment. Seven months after surgery, an Artisan^® Aphakia iris-claw lens was implanted in the anterior chamber. Fifteen months of follow-up data are provided.

Successful visual rehabilitation in a case of anterior megalophthalmos

We report a case of 40-year-old female who presented with diminution of vision in both eyes. Ocular evaluation showed presence of bilateral megalocornea with deep anterior chamber, iridodonesis, cataract, and anterior embryotoxon. She was diagnosed with bilateral anterior megalophthalmos. She underwent an uneventful cataract extraction with standard posterior chamber intraocular lens implantation of overall large diameter in the left eye. Zonular dialysis was not evident intraoperatively despite the presence of iridodonesis. Postoperatively the intraocular lens was well centered throughout follow up. This case report reviews this rare disorder and highlights successful visual rehabilitation.

Artisan aphakic lens for cataract surgery in anterior megalophthalmos

A 44-year-old man with anterior megalophthalmos arrived at the clinic presenting a cataract in the right eye. The corneal diameter was 13 mm. Iridodonesis and phacodonesis were evident during slit lamp examination. Anterior chamber depth was 5.89 mm, and the diameter of the capsular bag was approximately 14.45 mm. Due to the large capsular bag, a standard posterior chamber intraocular lens was considered inadequate because of potential instability. Phacoemulsification and an implantation of an iris-claw lens (Artisan for aphakia^®, Ophtec) in the posterior chamber were performed with good results. In the fourth postoperative month, uncorrected distance visual acuity was 20/30, and 20/20 was achieved with +0.75 −1.25 × 10°. We consider retropupillary aphakic iris-claw intraocular lenses to be a worthwhile option in these cases of megalophthalmos and cataract, since instability is avoided and the procedure is less challenging than suturing the lens.

Application of ultrasound biomicroscopy in the planning of cataract surgery in anterior megalophthalmos

Anterior megalophthalmos, a rare hereditary disorder, is macrocornea (horizontal corneal diameter more than 13 mm) in association with enlarged lens-iris diaphragm and ciliary ring. One of the major challenging issues in the cataract surgery of these patients is preventing intraocular lens (IOL) malposition, because of probable large capsular bag. Several approaches have been selected by previous surgeons, such as, custom-made anterior chamber IOLs. In this study, we show a normal capsular bag diameter despite ciliary ring enlargement, with application of ultrasound biomicroscopy (UMB). We suggest that in cases of anterior megalophthalmos without phacodonesis, UBM could measure the actual size of the capsular bag and obviate the need for further procedures.

Phacoemulsification in anterior megalophthalmos

This case outlines the phacoemulsification technique used to overcome the challenge of the hyperdeep anterior chamber, weak zonules, abnormal anterior capsule, and large capsular bag. Key steps included trypan blue staining of the anterior capsule, a large capsulorhexis, prolapse of the nucleus into the anterior chamber with phacoemulsification anterior to the capsulorhexis, and a posterior chamber-placed iris-clip intraocular lens. Successful visual rehabilitation is achievable in these anatomically challenging eyes.