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Exam Review

Key Facts: CMO Oftalmología Exam

400 MCQs

Theory exam items (80 image cases x 5 questions), computer-based

CMO — ¿Cómo son los exámenes?

4 hours

Theory exam duration

CMO — ¿Cómo son los exámenes?

75 / 100

Minimum final grade (average of both parts)

CMO — ¿Cómo son los exámenes?

MXN 6,000

Exam fee

CMO — Requisitos

Aug / Nov 2026

Monterrey (21-22 Aug) and Mexico City (6-7 Nov) sittings

cmoregistro.com

The CMO certification is the CONACEM-recognized board exam for ophthalmology in Mexico: a practical patient exam with oral réplica plus a 400-item computer-based theory exam (80 image cases), averaged with a pass mark of 75. The fee is MXN 6,000, and 2026 sittings were in Monterrey (August) and Mexico City (November).

Sample CMO Oftalmología Practice Questions

Try these sample questions to review concepts for the CMO Oftalmología exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A 24-year-old soft contact lens wearer presents with a 2-day history of acute, intense pain, photophobia, and decreased vision in the right eye. Slit-lamp biomicroscopy reveals a 3.5 mm central corneal ulcer with a dense, yellowish-green suppurative stromal infiltrate, rapid stromal thinning (keratomalacia), and an associated 1.5 mm hypopyon. Corneal scrapings show Gram-negative rods. Which pathogen is the most likely causative agent, and what is the recommended immediate empiric therapy?
A.Pseudomonas aeruginosa; treat immediately with intensive fortified topical tobramycin (14 mg/mL) alternating with fortified cefazolin (50 mg/mL) or fluoroquinolone monotherapy
B.Staphylococcus aureus; treat immediately with topical natamycin 5% suspension and oral fluconazole
C.Acanthamoeba castellanii; treat immediately with topical polyhexamethylene biguanide (PHMB 0.02%) and oral voriconazole
D.Herpes simplex virus; treat immediately with topical trifluridine 1% drops and high-dose oral acyclovir
Explanation: Pseudomonas aeruginosa is the most common and aggressive causative organism of contact lens-related bacterial keratitis. It produces virulence factors including elastase, alkaline protease, and exotoxin A, causing rapid liquefactive necrosis (stromal melting) and hypopyon. Empiric therapy for severe central ulcers requires immediate, intensive bactericidal broad-spectrum topical therapy, either with fortified dual antibiotics (aminoglycoside like tobramycin 14 mg/mL alternating with a first-generation cephalosporin like cefazolin 50 mg/mL) or intensive fluoroquinolone monotherapy, dosed every 15–30 minutes initially.
2A 45-year-old agricultural laborer presents with ocular irritation and redness in his left eye 10 days after corneal trauma from a tree branch. Biomicroscopy reveals a grayish-white stromal infiltrate with feathery, indistinct margins, multiple discrete satellite lesions, and an endothelial plaque. Corneal scraping with potassium hydroxide (KOH) wet mount shows septate hyphae. Which topical medication is the initial first-line therapy of choice according to clinical guidelines?
A.Topical amphotericin B 0.15% drops every hour
B.Topical natamycin 5% ophthalmic suspension every 1 to 2 hours
C.Topical fortified vancomycin (50 mg/mL) monotherapy
D.Topical ganciclovir 0.15% ophthalmic gel 5 times daily
Explanation: The clinical presentation (vegetative ocular trauma, feathery infiltrate borders, satellite lesions, endothelial plaque) is classic for filamentous fungal keratitis, most commonly caused by Fusarium or Aspergillus species. The Mycotic Ulcer Treatment Trial (MUTT I) established that topical natamycin 5% suspension is significantly superior to topical voriconazole in visual acuity outcomes and reduction of corneal perforation for filamentous fungal keratitis, making natamycin the first-line drug of choice.
3A 22-year-old woman who routinely cleans her disposable contact lenses with tap water presents with excruciating right eye pain, photophobia, and blurred vision for 3 weeks. Her pain is noted to be markedly out of proportion to early examination findings. Slit-lamp biomicroscopy demonstrates radial perineural infiltrates (radial keratoneuritis) along corneal nerves and a partial stromal ring-shaped infiltrate. Which diagnostic tool provides rapid in-office confirmation, and what is the definitive medical treatment regimen?
A.Rose bengal staining showing devitalized epithelial borders; treat with topical trifluridine and oral valacyclovir
B.Giemsa staining demonstrating multinucleated giant cells; treat with oral acyclovir and topical dexamethasone
C.Confocal microscopy or Calcofluor white stain showing double-walled cysts; treat with topical biguanide (PHMB 0.02% or chlorhexidine 0.02%) combined with a diamidine (propamidine)
D.Bacterial blood agar culture demonstrating beta-hemolysis; treat with topical fortified ceftazidime and ciprofloxacin
Explanation: The clinical scenario of contact lens use exposed to tap water, extreme pain out of proportion to biomicroscopy, radial keratoneuritis, and a late ring infiltrate is pathognomonic for Acanthamoeba keratitis. Confocal microscopy or Calcofluor white fluorescent staining of corneal scrapings rapidly detects Acanthamoeba trophozoites and polygonal double-walled cysts. Medical therapy requires cysticidal agents: topical biguanides (polyhexamethylene biguanide [PHMB] 0.02% or chlorhexidine 0.02%) combined with diamidines (propamidine isethionate 0.1% or hexamidine).
4A 38-year-old man presents with unilateral ocular discomfort, watery discharge, and mild blurriness in his left eye. Slit-lamp examination demonstrates reduced corneal sensation and a branching epithelial lesion with terminal bulbs that stains positively with fluorescein in the ulcer bed and with rose bengal at the swollen margins. What is the standard first-line management, and which medication is strictly contraindicated?
A.Initiate topical ketorolac 0.5% drops; topical chloramphenicol is strictly contraindicated due to aplastic anemia risk
B.Initiate oral doxycycline and preservative-free tears; topical cyclosporine 0.05% is strictly contraindicated
C.Perform immediate superficial corneal debridement alone; oral acyclovir is strictly contraindicated in active epithelial disease
D.Initiate topical ganciclovir 0.15% ophthalmic gel or oral acyclovir; topical corticosteroids are strictly contraindicated
Explanation: The lesion is a classic dendritic epithelial ulcer caused by Herpes Simplex Virus (HSV-1) keratitis, characterized by linear branching with terminal buds and decreased corneal sensation. Standard antiviral therapy consists of topical ganciclovir 0.15% gel (or trifluridine 1%) or oral acyclovir (400 mg 5 times daily) / valacyclovir (500 mg tid). Topical corticosteroids are strictly contraindicated during active epithelial replication because they enhance viral proliferation, transform dendrites into extensive geographic ulcers, and increase corneal perforation risk.
5A 48-year-old patient with a past history of recurrent herpes simplex dendritic keratitis presents with painless visual decrease in the right eye. Slit-lamp biomicroscopy reveals a focal, central disc of stromal edema with keratic precipitates strictly localized underlying the edema zone, an intact corneal epithelium with no fluorescein staining, and mild anterior chamber flare. What is the diagnosis and the appropriate therapeutic strategy?
A.HSV immune stromal (disciform) keratitis; treat with topical corticosteroids under prophylactic antiviral cover
B.HSV necrotizing stromal keratitis; treat with aggressive surgical corneal debridement and topical moxifloxacin
C.Fungal keratitis; treat with topical amphotericin B drops and anterior chamber tap
D.Cytomegalovirus endotheliitis; treat with oral valganciclovir monotherapy without topical medications
Explanation: HSV immune stromal keratitis (disciform keratitis) is an antigen-antibody-complement-mediated delayed-type hypersensitivity reaction against retained viral antigens in the stroma/endothelium. It presents with localized disc-shaped stromal and epithelial edema, keratic precipitates localized beneath the edema, an intact epithelium, and no active necrosis. The Herpetic Eye Disease Study (HEDS) demonstrated that disciform keratitis responds effectively to topical corticosteroids (prednisolone acetate 1%) tapered gradually, always accompanied by therapeutic or prophylactic oral acyclovir (400 mg bid) to prevent viral epithelial recurrence.
6A 66-year-old man presents with painful vesicular skin eruptions strictly respecting the midline on his right forehead and scalp. Biomicroscopy shows punctate epithelial erosions and mild anterior chamber flare. On physical examination, skin vesicles are observed on the tip and side of the nose (Hutchinson sign). What is the anatomical significance of Hutchinson sign, and what is the first-line oral systemic antiviral regimen?
A.Involvement of the infraorbital nerve; treat with oral acyclovir 400 mg twice daily for 5 days
B.Involvement of the nasociliary branch of the ophthalmic division (V1); treat with oral valacyclovir 1000 mg three times daily for 7 to 10 days
C.Involvement of the zygomaticotemporal nerve; treat with oral oseltamivir 75 mg twice daily for 5 days
D.Involvement of the motor root of the facial nerve (VII); treat with oral amantadine 100 mg daily for 14 days
Explanation: In Herpes Zoster Ophthalmicus (HZO), vesicles on the tip, side, or ala of the nose constitute Hutchinson sign, indicating involvement of the external nasal branch of the nasociliary nerve (a branch of the ophthalmic division of the trigeminal nerve, V1). Because the nasociliary nerve also provides sensory innervation to the ocular globe (cornea, ciliary body, iris), Hutchinson sign correlates with a three- to four-fold increased risk of severe intraocular complications (keratitis, anterior uveitis, secondary glaucoma). First-line systemic treatment is oral valacyclovir (1000 mg tid) or oral acyclovir (800 mg 5 times daily) initiated within 72 hours of rash onset.
7A 62-year-old woman reports progressive bilateral morning blurriness and glare that gradually improves throughout the afternoon. Slit-lamp biomicroscopy reveals central endothelial guttata ('beaten bronze' or 'beaten metal' appearance on specular reflection), stromal haze, and early subepithelial bullae in both eyes. Central corneal thickness (CCT) is 645 µm in the right eye. Which surgical procedure is currently the preferred standard of care for isolated endothelial decompensation without significant stromal scarring?
A.Deep anterior lamellar keratoplasty (DALK)
B.Radial keratotomy with phototherapeutic keratectomy
C.Descemet membrane endothelial keratoplasty (DMEK)
D.Total penetrating keratoplasty (PKP) with 10-0 nylon running sutures
Explanation: The clinical picture is diagnostic of advanced Fuchs Endothelial Corneal Dystrophy (FECD) with symptomatic endothelial decompensation and diurnal morning edema (due to reduced evaporation during sleep). Modern surgical management of endothelial failure in the absence of deep anterior stromal scarring is selective endothelial keratoplasty. Descemet Membrane Endothelial Keratoplasty (DMEK) transplants solely donor Descemet membrane and endothelium, resulting in faster visual recovery, higher rates of 20/20 vision, and significantly lower allograft rejection rates (<1–2%) compared to full-thickness penetrating keratoplasty or DSAEK.
8An ophthalmology resident reviews histopathology slides of corneal stromal dystrophies. One specimen demonstrates diffuse, poorly demarcated cloudy stromal deposits that stain intensely with Alcian blue and colloidal iron, and genetic testing confirms an autosomal recessive CHST6 gene mutation. Which corneal dystrophy is represented?
A.Granular dystrophy type 1 (Groenouw type I)
B.Lattice corneal dystrophy type 1
C.Avellino corneal dystrophy (Granular type 2)
D.Macular corneal dystrophy
Explanation: Macular corneal dystrophy is the only major stromal dystrophy inherited in an autosomal recessive pattern (linked to mutations in CHST6 encoding carbohydrate sulfotransferase). Histopathologically, it features intra- and extracellular accumulations of abnormal glycosaminoglycans (mucopolysaccharides) that stain with Alcian blue and colloidal iron. Clinically, it presents with diffuse, indistinct grayish-white stromal opacities extending from limbus to limbus across the full stromal thickness. In contrast, Lattice (amyloid, Congo red) and Granular (hyaline, Masson trichrome) dystrophies are autosomal dominant TGFBI-linked conditions.
9A 34-year-old female presents with recurrent episodes of sharp, sudden right ocular pain and tearing upon awakening in the morning. Slit-lamp biomicroscopy reveals subtle intraepithelial microcysts, geographic fingerprint lines, and redundant basement membrane duplications in the central cornea. A diagnosis of epithelial basement membrane dystrophy (EBMD / Map-dot-fingerprint dystrophy) complicated by recurrent corneal erosion syndrome is made. Which initial conservative medical management is most appropriate?
A.Hypertonic sodium chloride (5%) ointment at bedtime with frequent preservative-free artificial tears during the day
B.Immediate full-thickness penetrating keratoplasty
C.Topical prednisolone acetate 1% four times daily for 6 months
D.Topical atropine 1% drops twice daily and eye patching for 4 weeks
Explanation: EBMD is the most common anterior corneal dystrophy, characterized by abnormal basement membrane extension into the epithelium, preventing normal hemidesmosomal adhesion. Upon opening the eyelids in the morning, shearing forces tear the unanchored epithelium, precipitating recurrent corneal erosion syndrome (RCES). First-line conservative medical therapy aims to promote epithelial adherence and dehydrate microcystic edema using hypertonic sodium chloride 5% ophthalmic ointment at bedtime, frequent preservative-free ocular lubricants during the day, and short-term bandage contact lenses if an acute erosion occurs.
10A 17-year-old male with a history of vigorous eye rubbing and allergic conjunctivitis presents with progressive astigmatism. Pentacam corneal tomography demonstrates an inferior paracentral steepening, thinnest pachymetry of 430 µm, maximum keratometry (Kmax) progression from 47.5 D to 49.2 D over 6 months, and abnormal posterior elevation. What is the primary therapeutic intervention indicated to halt further disease progression?
A.Topical cyclosporine 0.05% monotherapy without follow-up
B.Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A irradiation
C.Immediate penetrating keratoplasty with a 8.5 mm donor button
D.Implantation of an anterior chamber phakic intraocular lens
Explanation: The patient has progressive keratoconus, evidenced by progressive corneal steepening (increase in Kmax >1.0 D over 6 months), thinning, and asymmetric astigmatism. Corneal collagen cross-linking (CXL) using riboflavin (vitamin B2) photosensitizer and ultraviolet-A (365 nm) light induces covalent bonds between stromal collagen fibrils and proteoglycans, halting or significantly slowing the biomechanical progression of ectasia. Standard epithelial-off CXL requires a minimum de-epithelialized stromal thickness of 400 µm to safeguard the endothelial cell monolayer.

About the CMO Oftalmología Exam

Independent study practice by OpenExamPrep for the certification exam of the Consejo Mexicano de Oftalmología, A.C. (CMO), a CONACEM-recognized specialty council. The official exam has two parts of equal value: a practical patient examination with oral réplica, and a computer-based theory exam of 80 image-supported clinical cases with 5 multiple-choice questions each (400 items, 4 hours); a final average of 75 or higher passes. This bank is an independent English-language MCQ study adaptation of the theory content built on standard ophthalmic references and landmark trials; it is not an official translation or simulation of the Spanish-language CMO exam and does not cover the practical part.

Exam sponsor: Consejo Mexicano de Oftalmología, A.C. (CMO). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

The CMO certification exam has two parts of equal value. In the practical part, the candidate examines an assigned patient, records a clinical history and then defends the case in an oral réplica before 3 or 4 sinodales (about 45 minutes). The theoretical part is taken on computer: 80 clinical cases, each with a clinical vignette and images, and 5 multiple-choice questions per case (400 items), in 4 hours starting at 8:00. A final average of 75 or higher is required, and results are delivered the same day in a sealed envelope.

Time Limit

4 hours (theoretical) + 45 minutes (practical)

Passing Score

75/100

Exam / Certification Fees

MXN 6,000

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Weight not published

Córnea, Superficie Ocular y Segmento Anterior

Diagnostic evaluation and management of infectious keratitis (bacterial, fungal, viral, Acanthamoeba), corneal dystrophies and ectasias (keratoconus, CXL, keratoplasty), dry eye disease (TFOS DEWS II), chemical burns, and ocular surface reconstruction

Weight not published

Cristalino, Catarata y Cirugía Refractiva

Preoperative biometry formulas, surgical steps of phacoemulsification, management of intraoperative complications (capsular tears, zonular dialysis, vitreous loss), endophthalmitis prophylaxis and intervention, and keratorefractive surgery (LASIK, PRK, SMILE)

Weight not published

Glaucoma

Pathophysiology and staging of primary open-angle glaucoma, acute and chronic angle closure, secondary glaucomas (pseudoexfoliation, pigmentary, neovascular), gonioscopic assessment, ocular hypotensive pharmacotherapy, laser procedures, and filtration/shunt surgery

Weight not published

Retina, Vítreo y Uveítis

Diabetic retinopathy staging and anti-VEGF therapy for macular edema, retinal vascular occlusions, neovascular and non-neovascular AMD, rhegmatogenous retinal detachment repair, central serous chorioretinopathy, and infectious/autoimmune uveitis syndromes

Weight not published

Estrabismo, Neuroftalmología y Oculoplástica/Órbita

Evaluation and alignment surgery for esotropia and exotropia, amblyopia management, cranial nerve palsies (III, IV, VI), optic neuritis and ischemic optic neuropathies, pupillary abnormalities, myasthenia gravis, thyroid eye disease, and eyelid malpositions

Preparing for the CMO Oftalmología Exam

What You Need to Know

  • Passing score: 75/100
  • Assessment: The CMO certification exam has two parts of equal value. In the practical part, the candidate examines an assigned patient, records a clinical history and then defends the case in an oral réplica before 3 or 4 sinodales (about 45 minutes). The theoretical part is taken on computer: 80 clinical cases, each with a clinical vignette and images, and 5 multiple-choice questions per case (400 items), in 4 hours starting at 8:00. A final average of 75 or higher is required, and results are delivered the same day in a sealed envelope.
  • Time limit: 4 hours (theoretical) + 45 minutes (practical)
  • Exam / certification fees: MXN 6,000 Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

CMO Oftalmología: Suggested Study Strategy

1Master the differentiating clinical and biomicroscopic features of infectious keratitis: rapid stromal melting in Pseudomonas, feathery borders and satellite lesions in fungal keratitis, and perineural infiltrates with severe pain in Acanthamoeba.
2Review the ETDRS classification for diabetic retinopathy, memorizing the 4:2:1 rule for severe NPDR and the specific indications for anti-VEGF therapy versus panretinal photocoagulation in high-risk PDR.
3Understand IOP lowering mechanisms and systemic side effect profiles of all glaucoma medications, especially the cardiovascular/pulmonary risks of non-selective beta-blockers and the renal/metabolic risks of systemic carbonic anhydrase inhibitors.
4Memorize the Parks-Bielschowsky three-step test for diagnosing fourth cranial nerve (superior oblique) palsy and know how to differentiate pupil-involving (aneurysmal emergency) from pupil-sparing (microvascular) third nerve palsies.
5Be proficient in evaluating visual field defects on Humphrey perimetry (arcuate scotomas, nasal steps, homonymous hemianopias, bitemporal hemianopias) and correlating them with retinal nerve fiber layer OCT and anatomical visual pathway lesions.

Frequently Asked Questions

What is the Consejo Mexicano de Oftalmología (CMO) certification exam?

It is the board certification exam of the Consejo Mexicano de Oftalmología, A.C. (CMO), one of the specialty councils recognized by CONACEM. Certified ophthalmologists receive a diploma with the CONACEM seal about 90 days after passing.

How is the CMO exam structured?

It has two parts of equal value. In the practical part you examine an assigned patient and then defend the case in an oral réplica before 3 or 4 sinodales (about 45 minutes). The theory part is computer-based: 80 clinical cases with vignettes and images, each followed by 5 multiple-choice questions (400 items), with 4 hours to complete it.

What is the pass mark, and when are results given?

The final grade is the average of the two parts and must be 75 or higher. Results are handed out the same day, in a sealed envelope, at a results ceremony.

How do I register, and how much does it cost?

Applications are submitted on cmoregistro.com during each convocatoria, with places limited by venue. The documents include the application letter, CV, medical degree and cédula, CURP, RFC and the specialty diploma (or a letter confirming residency completion before the exam). The exam fee is MXN 6,000, and cancellations 60 days or less before the exam are not refunded. The 2026 second-semester sittings were in Monterrey (21-22 August) and Mexico City (6-7 November).

Why is this practice bank in English, and does it cover the practical exam?

The CMO exam is conducted in Spanish. This OpenExamPrep bank is an independent English-language MCQ study adaptation of the theory content; it is not an official translation or simulation of the CMO exam, and it does not replicate the practical patient examination or oral réplica.