Multifocal toric IOL implantation in a patient with Alport syndrome, anterior lenticonus, and intermittent exotropia: a case report

Abstract

Background

Alport syndrome is a hereditary disorder characterized by renal failure, sensorineural hearing loss, and ocular manifestations. Anterior lenticonus is the most pathognomonic ocular feature, whereas strabismus is rarely reported. Intraocular lens (IOL) implantation in such patients can be challenging due to lens capsule fragility and coexisting visual problems.

Case presentation

We report a patient with Alport syndrome presenting with anterior lenticonus and intermittent exotropia, who underwent sequential bilateral phacoemulsification with multifocal toric IOL implantation. Preoperative examination revealed high myopic astigmatism and reduced visual acuity. Strabismus evaluation showed intermittent exotropia with greater deviation at near. Surgery was performed with meticulous hydrodelineation and careful capsulorrhexis. A multifocal toric IOL was successfully implanted and oriented along the intended axis. At the 6-month postoperative follow-up, uncorrected distance visual acuity was maintained at 0.05 LogMAR (Snellen 20/22) and uncorrected near visual acuity was N5 at 40 cm in both eyes; no severe visual disturbances were detected, and no complications such as capsular contraction or IOL decentration were observed.

Conclusion

Bilateral trifocal toric intraocular lens implantation may provide satisfactory visual rehabilitation in selected patients with Alport syndrome and anterior lenticonus, even in the presence of coexisting intermittent exotropia.

Background

Alport syndrome is a hereditary disorder caused by mutations in type IV collagen genes affecting basement membranes. It is characterized by progressive renal failure, sensorineural hearing loss, and several ocular manifestations. The disease is most commonly inherited in an X-linked pattern, although autosomal recessive and autosomal dominant forms have also been described [1]. Clinical severity is generally greater in males due to the predominance of X-linked inheritance [2].

Ocular findings in Alport syndrome include anterior lenticonus, perimacular retinal flecks, posterior polymorphous corneal dystrophy, and various refractive abnormalities. Among these manifestations, anterior lenticonus is considered the most characteristic ocular feature and often leads to progressive visual deterioration due to increasing lenticular myopia and astigmatism. The conical protrusion of the anterior lens capsule produces the typical “oil droplet” reflex and may significantly impair visual quality [1]. Although ocular associations are well documented, strabismus has rarely been described in the context of Alport syndrome.

Surgical management of anterior lenticonus usually involves cataract extraction with intraocular lens (IOL) implantation. However, surgery in these patients can be technically challenging because the anterior lens capsule is structurally weakened and prone to tearing during capsulorrhexis. Careful surgical technique is therefore essential to avoid intraoperative complications [3].

The coexistence of Alport syndrome, anterior lenticonus, and strabismus is extremely rare. In addition, the use of premium intraocular lenses in such cases raises several clinical considerations. Multifocal IOLs require accurate centration and stable ocular alignment to provide optimal visual performance, while toric designs are necessary to correct high corneal astigmatism. The presence of strabismus may theoretically compromise postoperative binocular visual outcomes and therefore represents an additional challenge when selecting an appropriate IOL.

Herein, we report the surgical management and visual outcomes of a patient with Alport syndrome, anterior lenticonus, and intermittent exotropia who underwent sequential bilateral cataract surgery with implantation of a trifocal toric intraocular lens. This case highlights the importance of individualized surgical planning in complex ocular conditions and demonstrates that satisfactory visual rehabilitation can be achieved even in the presence of multiple coexisting challenges.

Case presentation

A 49-year-old male patient with a known history of Alport syndrome, who had undergone cadaveric kidney transplantation seven years earlier following seventeen years of hemodialysis, presented with progressive visual deterioration since childhood. The patient also had sensorineural hearing loss, consistent with the systemic manifestations of Alport syndrome.

Preoperative refraction was measured as − 14.50 − 5.50 × 180 in the right eye and − 17.50 − 9.00 × 180 in the left eye. Best-corrected visual acuity (BCVA) was 0.22 LogMAR (Snellen 6/10) in the right eye and 0.52 LogMAR (Snellen 20/60) in the left eye, with no significant improvement with refractive correction. Intraocular pressure measured by applanation tonometry was 17 mmHg in the right eye and 18 mmHg in the left eye.

Slit-lamp examination revealed bilateral anterior lenticonus with the characteristic oil-droplet reflex (Fig. 1). Arcus senilis and lenticular opacity were also observed in both eyes. The anterior capsule appeared intact on slit-lamp evaluation (Fig. 2).

Fig. 1.

Typical oil droplet reflex of the (a) right and (b) left eye seen in anterior lenticonus

Fig. 2.

Anterior segment optical coherence tomography showing anterior conical protrusion of lens capsule of the (a) right eye and (b) left eye

Dilated fundus examination demonstrated a cup-to-disc ratio of 0.2 in both eyes with normal macular and peripheral retinal appearance (Fig. 3). Optical coherence tomography (OCT) and OCT angiography of the macula were within normal limits (Figs. 4 and 5).

Fig. 3.

Fundus photographs appearing normal of the (a) right eye and (b) left eye

Fig. 4.

OCT examination of the (a) right eye and (b) left eye

Fig. 5.

OCT angiography examination of the right (upper) and left (lower) eye a)Superficial capillary plexus b)Deep capillary plexus c)Outer retina(avascular layer) d)choriocapillaris

Specular microscopy revealed endothelial cell densities of 2257 cells/mm² in the right eye and 2337 cells/mm² in the left eye.

Axial length measurements obtained with Lenstar 900 APS Pro were 22.72 mm in the right eye and 22.69 mm in the left eye, which were within normal limits despite the presence of high myopic refractive error. Corneal topography (Sirius, CSO, Italy) demonstrated keratometric values of K1: 43.50 × 180 and K2: 46.69 × 90 in the right eye, and K1: 43.05 × 180 and K2: 45.74 × 90 in the left eye (Fig. 6). Intraocular lens power was calculated using the Barrett Toric Calculator.

Fig. 6.

Corneal topography of the (a) right eye and (b) left eye

Strabismus evaluation demonstrated intermittent exotropia. Hirschberg testing showed approximately 10° of intermittent exotropia. Prism cover testing demonstrated 40 prism diopters (PD) of deviation at near fixation. Preoperative distance deviation could not be reliably quantified because of poor fixation secondary to severe visual impairment. Convergence was minimally impaired. Titmus stereotest revealed 800 arc-seconds of stereopsis. Ocular motility was full and head posture was normal. The patient did not report constant diplopia in daily life preoperatively, although intermittent visual discomfort during prolonged near work was reported.

The patient underwent sequential bilateral cataract surgery performed two weeks apart, with the right eye operated first followed by the left eye, and trifocal toric intraocular lenses implanted in both eyes.

Preoperative axis markings were performed at the slit lamp using an Epsilon marker (Ontario, CA, USA). Surgery was performed under sub-Tenon anesthesia. Intraoperative axis alignment was confirmed using an ASICO gauge. Two side-port incisions were created at the 2 and 10 o’clock positions, followed by injection of high-molecular-weight viscoelastic (sodium hyaluronate 1.4%) into the anterior chamber. A 2.2-mm clear corneal incision was made at the 12 o’clock position. Because the anterior capsule in Alport syndrome is fragile and prone to radial tearing, capsulorrhexis was initiated from the mid-peripheral capsule using a 26-gauge cystotome and completed with microforceps, resulting in a continuous curvilinear capsulorrhexis. Hydrodissection was intentionally avoided due to the increased risk of capsular rupture in eyes with fragile anterior capsules. Instead, careful hydrodelineation was performed, followed by low-power phacoemulsification. Residual cortical material was removed using irrigation-aspiration cannulas.

After filling the capsular bag with viscoelastic, a RayOne Trifocal Toric intraocular lens (Rayner, Worthing, UK) (SE 22.5 D, Sph + 21.0 D, Cyl + 3.0 D) was implanted in the capsular bag and aligned with the predetermined axis. Viscoelastic material was removed and corneal wounds were sealed with stromal hydration (Fig. 7).

Fig. 7.

Intraoperative images demonstrate surgical steps: a)preoperative axis marking with epsilon marker b)subtenon’s injection c)intraoperative axis marking with asico gauge d) capsule staining e)initiation of capsulorrhexis with cystotome f) propagation of capsulorrhexis with microforceps g)completed intact capsulorrhexis h)hydrodelineation i)phacoemulsification with low parameters j) cortex aspiration k) multifocal toric IOL implanted l) multifocal toric IOL centralisation

Postoperatively, the intraocular lenses were well centered and stable without rotation (Fig. 8). Residual refractive error was − 0.50 D cylinder at 30° in the right eye and − 0.25 D cylinder at 15° in the left eye. Postoperative uncorrected visual acuity was 0.05 LogMAR (Snellen 20/22) and uncorrected near visual acuity was N5 at 40 cm in both eyes. However, the patient reported improved comfort during near tasks when one eye was occluded.

Fig. 8.

Postoperative slit lamp image shows stable centered multifocal toric intraocular lens of the (a) right and (b) left eye

At the six-month postoperative follow-up, uncorrected distance visual acuity was maintained at 0.05 LogMAR (Snellen 20/22), while uncorrected near visual acuity remained N5 at 40 cm in both eyes. IOL positioning remained stable, with no evidence of capsular contraction or lens decentration.

Strabismus examination demonstrated persistent intermittent exotropia of approximately 10°, with 35 PD deviation at near and 20 PD at distance. Titmus stereotest improved to 100 arc-seconds, and Worth four-dot testing demonstrated normal fusion at distance. Postoperative ocular alignment of the two eyes is shown in Fig. 9.

Fig. 9.

Ocular alignment of the two eyes after sequential bilateral cataract surgery with near fixation. The image was cropped to preserve patient anonymity while demonstrating ocular alignment

Quality of vision was evaluated using the Quality of Vision (QoV) questionnaire, proposed by the McAlinden et al. [4], and results are summarized in Table 1.

Table 1.

Postoperative Quality of Vision questionnaire results at 3 months

	Frequency(0 = Never, 1 = Occasionally, 2 = Often, 3 = Always)	Severity(0 = None, 1 = Mild, 2 = Moderate, 3 = Severe)	Bothersome(0 = Not at all, 1 = A little, 2 = Quite, 3 = Very)
Glare	0	0	0
Halo	1	1	0
Starburst	1	1	0
Hazy vision	1	1	0
Blurred vision	1	2	2
Distortion	0	0	0
Double image	0	0	0
Fluctuation	1	1	1
Focusing difficulty	2	2	2
Depth perception	1	1	1

Discussion and conclusions

Alport syndrome is a hereditary basement membrane disorder characterized by progressive renal failure, sensorineural hearing loss, and ocular manifestations including anterior lenticonus, posterior polymorphous corneal dystrophy, and retinal flecks. Among these, anterior lenticonus is considered pathognomonic and typically leads to significant visual impairment requiring surgical intervention [1, 2]. Our patient, who had previously undergone kidney transplantation following long-term hemodialysis and presented with sensorineural hearing loss, demonstrated progressive bilateral visual loss due to anterior lenticonus associated with high myopia and astigmatism.

Cataract extraction with intraocular lens (IOL) implantation remains the treatment of choice for anterior lenticonus [3, 5]. However, surgical management is often challenging due to the increased fragility of the anterior lens capsule. Several studies have emphasized the tendency for radial extension of capsulorrhexis in these cases, highlighting the importance of careful technique and the use of microinstruments [3, 5, 6, 7]. In our patient, meticulous capsulorrhexis with a cystotome and microforceps, combined with hydrodelineation and controlled low-power phacoemulsification, allowed safe lens removal without intraoperative complications.

In recent years, advances in IOL technology have provided options not only for visual rehabilitation but also for spectacle independence. While monofocal IOLs have traditionally been used in Alport cases [3, 5], implantation of premium lenses, including multifocal and toric designs, has been rarely reported [8]. In our patient, a trifocal toric IOL was selected due to the high corneal astigmatism and the patient’s desire for spectacle independence across multiple distances.

The choice of intraocular lens material represents an important consideration, particularly in relatively young patients. Although hydrophobic acrylic lenses may offer a lower long-term risk of calcification [9], the presence of high corneal astigmatism and the patient’s expectation for spectacle independence necessitated the use of a trifocal toric design in this case. At the time of surgery, available trifocal toric options were limited, and the selected lens provided the most appropriate optical solution for simultaneous correction of presbyopia and corneal astigmatism. Nevertheless, the potential long-term risk of calcification associated with hydrophilic materials should be considered, and careful long-term follow-up is warranted.

Postoperatively, the patient achieved satisfactory uncorrected visual acuity, with stable lens positioning and minimal residual refractive error. Importantly, despite the presence of intermittent exotropia and reduced stereopsis preoperatively, binocular vision outcomes improved after surgery, with enhanced stereopsis and preserved fusion responses on Worth 4-dot testing. In our case, intermittent exotropia persisted without affecting functional distance vision. However, the patient reported improved comfort during near tasks when one eye was occluded, suggesting that binocular interaction at close distances may still influence subjective visual performance.

Restoration of visual acuity after cataract surgery may disrupt longstanding sensory adaptations and may unmask or worsen diplopia in patients with latent or intermittent strabismus [10, 11]. Therefore, careful preoperative orthoptic evaluation and detailed patient counseling are essential when considering multifocal intraocular lens implantation in patients with ocular misalignment [10,11].

Visual disturbances such as glare, halos, and starbursts are well-documented after multifocal IOL implantation [12]. In a previously reported case, a patient with amblyopia and strabismus was unable to tolerate implantation of a multifocal toric intraocular lens, which necessitated lens exchange [13]. Another study reported that exchanging a multifocal IOL for a monofocal lens improved dysphotopsia and distance vision, but resulted in worsening UNVA (uncorrected near visual acuity) and persistent dissatisfaction in most patients, underscoring the importance of maintaining near visual function [14].

In the present case, the QoV questionnaire administered at three months demonstrated minimal dysphotopsia that gradually resolved and did not cause significant discomfort. Notably, the patient tolerated the multifocal toric IOL well despite the presence of intermittent exotropia. The primary complaint involved difficulty performing fine near tasks at very close distances (approximately 20 cm), such as manipulating small objects or tightening screws. Additionally, the patient reported subtle differences in visual quality between day and night, with near visual tasks representing the main functional limitation. Despite experiencing occasional moderate blurring, the patient expressed high overall satisfaction with the visual outcome, mainly due to the significant improvement in visual acuity and the ability to perform daily activities without spectacle dependence.

One limitation of this report is the absence of preoperative QoV questionnaire data, which precluded direct comparison of visual quality before and after surgery. Preoperative QoV assessment was not feasible due to the patient’s severely reduced visual quality caused by advanced anterior lenticonus. Therefore, the QoV questionnaire was used primarily to document postoperative visual quality and dysphotopsia symptoms.

Although implantation of multifocal intraocular lenses in eyes with strabismus has traditionally been approached with caution due to potential binocular vision disturbances, several recent reports have demonstrated satisfactory visual outcomes in carefully selected patients. Furthermore, toric multifocal intraocular lenses have been shown to provide effective correction of both corneal astigmatism and presbyopia, improving spectacle independence and overall visual function. In the present case, despite the presence of intermittent exotropia, stable binocular vision and satisfactory postoperative visual quality were achieved. Because binocular fusion was relatively preserved and the patient’s primary complaint was severe visual deterioration related to anterior lenticonus, cataract surgery was prioritized over strabismus surgery. Nevertheless, the patient was counseled regarding the potential risk of postoperative diplopia and the possible future need for strabismus management.

To our knowledge, this is the first reported case describing the use of bilateral trifocal toric intraocular lens implants in a patient with Alport syndrome, anterior lenticonus, and intermittent exotropia, representing a feasible surgical option in such complex clinical scenarios. Careful patient selection and realistic expectation counseling remain essential when considering multifocal toric IOL implantation in patients with coexisting strabismus.

Author contributions

All authors contributed to the study. The first draft of the case report was written by G.B. and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Funding

This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

The datasets used during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was conducted according to the principles of the Declaration of Helsinki. Approval of the ethics committee of our hospital was not required because this was a single case report.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Competing interests

The authors declare no competing interests.